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https://arxiv.org/abs/1204.3752
|
cs.IT
(what is this?)
# Title:GPS Information and Rate Tolerance - Clarifying Relationship between Rate Distortion and Complexity Distortion
Authors:Chenguang Lu
Abstract: I proposed rate tolerance and discussed its relation to rate distortion in my book "A Generalized Information Theory" published in 1993. Recently, I examined the structure function and the complexity distortion based on Kolmogorov's complexity theory. It is my understanding now that complexity-distortion is only a special case of rate tolerance while constraint sets change from fuzzy sets into clear sets that look like balls with the same radius. It is not true that the complexity distortion is generally equivalent to rate distortion as claimed by the researchers of complexity theory. I conclude that a rate distortion function can only be equivalent to a rate tolerance function and both of them can be described by a generalized mutual information formula where P(Y|X) is equal to P(Y|Tolerance). The paper uses GPS as an example to derive generalized information formulae and proves the above conclusions using mathematical analyses and a coding example. The similarity between the formula for measuring GPS information and the formula for rate distortion function can deepen our understanding the generalized information measure.
Comments: 6 pages, 4 figures Subjects: Information Theory (cs.IT); Computational Complexity (cs.CC) ACM classes: H.1.1; H.1.2; I.4.2; I.5.0 Cite as: arXiv:1204.3752 [cs.IT] (or arXiv:1204.3752v1 [cs.IT] for this version)
## Submission history
From: Chenguang Lu [view email]
[v1] Tue, 17 Apr 2012 10:48:14 UTC (311 KB)
|
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|
https://www.kasal.com/long-table-trellis-la-palma
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# “The Long Table” from Under the Trellis to “La Palma”
0
66
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Wedding banquets were always clarion calls for gathering kith and kin. No table was ever long enough to seat all. Hence the conjoined table boards to make one long table. The term has come to denote a nuptial feast. Where were the “long tables” spread in Grandmother’s time? Home was the traditional venue. Those cavernous elegant mga bahay na bato (stone houses) could contain the largest of social gatherings. There were armies of servants to attend the guests. To this day, in town and barrio, there’s a leafy trellis beside the bahay kubo shading the open-air long table. In the city, however, receptions at hotels and restaurants in time became fashionable. From twilight of the reign of Spain to morning of American Empire days en grande receptions were invariably at La Palma de Mallorca, a famous Spanish hostelry in Intramurous until well into the Twenties.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Source:
Alvina, C. & Sta. Maria, F. 1987. Essays on Philippine Culture.
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|
https://emacs.stackexchange.com/questions/32347/how-to-have-wrapped-text-when-exporting-from-org-to-latex
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# How to have wrapped text when exporting from org to Latex?
I have an org file which I export to LaTeX and then to a PDF document. The problem is I have some long text that exceeds the length of the page. How to wrap it so that it falls into the next line?
First example:
``````#+BEGIN_SRC c++
<code goes here> // very long comment that doesn't wrap ........
#+END_SRC
``````
The comment is very long and exceeds the length of the page, how to make it wrap?
Second example:
``````|------+------+------------------------+------|
| text | text | text | text |
|------+------+------------------------+------|
| text | text | very long texttt...... | text |
|------+------+------------------------+------|
``````
Some cells contain long text which also doesn't wrap, how to make it wrap?
From a LaTeX point of view, these are different cases.
In the first case, LaTeX isn't going to wrap -- and it shouldn't! A "verbatim" environment, which is what source-code is set in, respects lines precisely and doesn't break paragraphs, because LaTeX simply can't know where to break them. If you want to wrap the lines, you have to wrap them in the source-code itself.
In the second case, you can use `#+ATTR_LATEX` to help LaTeX format the table appropriately.
Simplest but least elegant approach: use `:align` with a `p` column to specify a width for the problematic column. LaTeX will then wrap that column to the specified width. So this specifies three columns: one aligned left, one a `p` column with a fixed width of 4cm, and another aligned left.
``````#+ATTR_LATEX: :align lp{4cm}l
``````
More elegant. Use `tabularx` and a `X` column, and LaTeX will then set the column to a length appropriate to enable a table of a fixed overall width. You need to `(add-to-list 'org-latex-packages-alist '("" "tabularx"))` I think.
``````#+ATTR_LATEX: :environment tabularx :width \textwidth :align lXl
| column | column with very very very very very overlong text which would flow over | last |
| column | shorter column | column |
| column | shorter column | column |
``````
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https://fa.braiins.com/blog/development-update-braiins-os-20-10
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We apologize but our blog is available only in English, Spanish and Russian.
# Development Update: Braiins OS+ 20.10
Full release of autotuning firmware for Antminer S17 and S17 Pro models. Plus 0% pool fees if you choose to mine with Slush Pool.
Published on Oct 26, 2020
Published on Oct 26, 2020
Today is a milestone release for Braiins OS+. It is the first full release for newer-generation ASICs, namely the Antminer S17 and S17 Pro. In addition, we have added the much anticipated beta support for the S17+, T17, and T17+ with this release.
In this update, we’ll provide an overview of features in the autotuning firmware for X17 models as well as the future of our open-source initiative as it pertains to Braiins OS and Stratum V2.
## Braiins OS+ 20.10 Overview
If you’re an existing Braiins OS+ user or you participated in our beta for S17 and S17 Pro models with the Braiins OS+ 20.09 release, then you’ll already be familiar with the core feature set of the firmware: per-chip autotuning, Dynamic Power Scaling, saved tuning profiles, pre-heating for miners in cold locations, and more. Here’s some of what’s new in the latest release.
### One install file for all S17 models
One new feature in this release is auto-detection of which hardware model in the S17 class that you’ve installed Braiins OS+ onto. In other words, there will be a single image for the S17, S17+, and S17 Pro, and BOSminer will automatically detect which machine type you’re using and dynamically set the default configuration (e.g. power limit) accordingly. (For now the S17+ is separate for the beta version.)
### New default temperature settings
Another noteworthy change from the beta release is that we’ve lowered default temperature limits to 72oC for the target temp, 85oC for the hot temp, and 92oC for the dangerous temp on X17 models. This was done because the S17 family is extra sensitive to overheating due to the manufacturer’s choice to use thermal glue as a solder material on the hashboard PCBs (Printed Circuit Boards) instead of the relatively higher-performance thermal paste that had been used in previous generations.
### NAND Flash and control board variations
In addition to machine type detection, there is also automatic detection of which control board variant your ASICs have (C49 or C52) in order to properly drive the fans. On a less positive note, there is a known issue with Macronix NAND Flash on S17 models that currently prevents the installation of Braiins OS+. We are working on a fix for this, but in the meantime only the Micron NAND Flash is supported. The vast majority of machines have Micron chips, so hopefully this issue is not relevant to you. The chips have brand names on them, so you can easily inspect your machines to determine which type they have.
### What happens if you uninstall Braiins OS+?
Finally, we’d like to clear up one point of confusion. If you use the BOS+ Toolbox to uninstall Braiins OS+, you will be installing stock firmware. For S9 models, the stock firmware is a pre-2019 version so that SSH remains unlocked. For S17 models, the stock firmware image is Antminer-S17-user-OM-201912250945-ssh.tar.gz which has unlocked SSH as well.
### Changelog 20.10
This is a major release that adds beta support for Antminer S17+
* All mining hardware types
* [feature] procd now waits up to 20s to allow proper shutdown of BOSminer
* [feature] BOSminer monitor now only spins the fans for when BOSminer has been stopped in order to cool down the machine
* [bug] stratum client no longer complains about 'Stratum: unexpected accepted solution #0'
* [bug] stratum client incorrect state bug has been fixed (i.e. you should not see "ERRO BUG: 'finish_shutdown_or_recover': unexpected state 'Starting'" anymore)
* [feature] referral program support has been made more robust to support multiple hardware types in a single referral configuration
* [feature] BOS management protocol is now relayed between devfee stratum V2 connections in case of fail over to a backup connection
* Antminer S9
* there were no hardware specific changes
* Antminer S17
* [feature] support for S17+ has been added
* [feature] default temperature limits have been lowered even further to target temp: 72 C, hot temp: 85 C, dangerous temp: 92 C as the S17 family is very sensitive to overheating due to quality of the solder material used on the hashboard PCB's
* [feature] we have added automatic detection of control board variant (C49 vs C52) to drive fans properly
* [feature] Braiins OS would refuse to install on X17 machines that have the 'Macronix' NAND flash. Currently, only the 'Micron' NAND flash is supported
* [feature] autodetection of S17, S17Pro, S17+ has been implemented and there is a single image for all of these machine types
* [feature] power limits are now dynamically calculated based on the detected machine
You can view the changelog also in our documentation.
See the full changelog
## Antminer S17+, T17, and T17+ Beta Testing
As was the case with the prior release for S17 and S17 Pro Antminers, this release is being labeled a beta for the S17+ due to the relatively limited external testing thus far. Besides getting more testing completed, another goal for the S17+ full release is to iterate on the tuning algorithms to work more effectively with high power limits (overclocking). S17 models are notorious for overheating issues, so we want to be extremely diligent about maximizing the tuner’s effectiveness when operating near peak capacity.
As mentioned in the previous development update, we’ve also been working on the T17 models in parallel with the S17 models as they are quite similar. The 20.10 build runs on both the T17 and T17+, so we plan to make it available in the nightly feed by the end of day tomorrow for anybody interested in trying it out.
Be aware that we have been more focused on the S17 models and have not yet performed thorough testing on the T17 models. If you have a larger operation, please test it on just a few machines at first before rolling it out to more machines if you are pleased with the results. We will be gathering data and feedback in the coming weeks in order to make the next update a full release for the T17 and T17+.
The best place to send us your feedback or get technical support is in our Telegram support groups, so join in if you haven’t already:
## Braiins Open-Source Initiative (BOSI) Update
With 20.10 being a milestone release in terms of the support added for new hardware, this is also a good time to provide an update on our open-source initiative in Bitcoin mining.
Due to some tooling limitations, we are not publishing sources for the Antminer S9 with this release. However, we will resolve the tooling and publish the full sources including the Stratum V2 implementation in Braiins OS 20.11, next month’s release. The most recently published sources can be found here.
As for the newer hardware we are supporting (Antminer S17, S17+, and S17 Pro now along with the T17 and T17+ in an upcoming release), our approach is going to differ from the Antminer S9.
In the case of this newer-generation hardware, we will not be publishing the full sources and instead focusing strictly on Braiins OS+ — at least for the foreseeable future. The biggest reason for this is that the autotuning firmware revenue is now a significant portion of our business, and we simply cannot afford to help our competitors by giving away the knowledge and code we’ve spent many intensive months to build. Writing BOSminer from scratch requires a comprehensive understanding of the ASIC architecture. As such, open-sourcing this code for newer-gen hardware would weaken one of our competitive advantages. In this ultra-competitive industry, it just doesn’t make sense.
Our Director of Business Development discusses changes to the mining pool industry and why we are focusing on firmware as a core part of the business.
At the same time, the incentive to continue dedicating resources to the open-source Braiins OS isn’t there. We’ve received minimal outside support and collaboration thus far on the open-source version for the S9, and even people who do build on top of our codebase haven’t been providing their code back.
That being said, we are not burying the open-source initiative. We remain open to the idea of publishing all sources for S17 models after 1 year or more has passed, if we feel that doing so will not significantly harm our business. Meanwhile, we will continue releasing Stratum V2 code for ALL hardware models, which can serve as a reference implementation for other firmwares to add V2 support.
## Development Pipeline
We will have two main focuses for the upcoming development cycle:
• Preparing full releases for the S17+, T17, and T17+ and fixing any issues that arise for all S17 and T17 models.
• Continuing to work on support for more hardware models, specifically the Whatsminer M20S and M21S.
Other hardware models on our radar include the Antminer S17e and T17e, as well as the newest generation from Bitmain and MicroBT — the S19 family and M30S family, respectively. We will be sure to inform you of our plans to support more hardware in the next development update.
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https://ps.is.tue.mpg.de/publications?publication_type%5B%5D=Miscellaneous&publication_type%5B%5D=Book&publication_type%5B%5D=Conference+Paper&year%5B%5D=2001&year%5B%5D=2005&year%5B%5D=1995&year%5B%5D=1999&year%5B%5D=1997&year%5B%5D=1996
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#### 2005
##### A quantitative evaluation of video-based 3D person tracking
Balan, A. O., Sigal, L., Black, M. J.
In The Second Joint IEEE International Workshop on Visual Surveillance and Performance Evaluation of Tracking and Surveillance, VS-PETS, pages: 349-356, October 2005 (inproceedings)
#### 2005
##### Inferring attentional state and kinematics from motor cortical firing rates
Wood, F., Prabhat, , Donoghue, J. P., Black, M. J.
In Proc. IEEE Engineering in Medicine and Biology Society, pages: 1544-1547, September 2005 (inproceedings)
##### Motor cortical decoding using an autoregressive moving average model
Fisher, J., Black, M. J.
In Proc. IEEE Engineering in Medicine and Biology Society, pages: 1469-1472, September 2005 (inproceedings)
##### Fields of Experts: A framework for learning image priors
Roth, S., Black, M. J.
In IEEE Conf. on Computer Vision and Pattern Recognition, 2, pages: 860-867, June 2005 (inproceedings)
##### On the receptive fields of Markov random fields: Predictions from a probabilistic model of scene statistics
Black, M. J., Roth, S.
COSYNE 2005, Salt Lake City, March 2005 (conference)
##### On the spatial statistics of optical flow
(Marr Prize, Honorable Mention)
Roth, S., Black, M. J.
In International Conf. on Computer Vision, International Conf. on Computer Vision, pages: 42-49, 2005 (inproceedings)
##### Modeling neural population spiking activity with Gibbs distributions
Wood, F., Roth, S., Black, M. J.
In Advances in Neural Information Processing Systems 18, pages: 1537-1544, 2005 (inproceedings)
##### Energy-based models of motor cortical population activity
Wood, F., Black, M.
Program No. 689.20. 2005 Abstract Viewer/Itinerary Planner, Society for Neuroscience, Washington, DC, 2005 (conference)
#### 2001
##### Dynamic coupled component analysis
De la Torre, F., Black, M. J.
In IEEE Proc. Computer Vision and Pattern Recognition, CVPR’01, 2, pages: 643-650, IEEE, Kauai, Hawaii, December 2001 (inproceedings)
#### 2001
##### Robust principal component analysis for computer vision
De la Torre, F., Black, M. J.
In Int. Conf. on Computer Vision, ICCV-2001, II, pages: 362-369, Vancouver, BC, USA, 2001 (inproceedings)
##### Learning image statistics for Bayesian tracking
In Int. Conf. on Computer Vision, ICCV-2001, II, pages: 709-716, Vancouver, BC, USA, 2001 (inproceedings)
##### Encoding/decoding of arm kinematics from simultaneously recorded MI neurons
Gao, Y., Bienenstock, E., Black, M., Shoham, S., Serruya, M., Donoghue, J.
Society for Neuroscience Abst. Vol. 27, Program No. 572.14, 2001 (conference)
##### Learning and tracking cyclic human motion
Ormoneit, D., Sidenbladh, H., Black, M. J., Hastie, T.
In Advances in Neural Information Processing Systems 13, NIPS, pages: 894-900, (Editors: Leen, Todd K. and Dietterich, Thomas G. and Tresp, Volker), The MIT Press, 2001 (inproceedings)
#### 1999
##### Edges as outliers: Anisotropic smoothing using local image statistics
Black, M. J., Sapiro, G.
In Scale-Space Theories in Computer Vision, Second Int. Conf., Scale-Space ’99, pages: 259-270, LNCS 1682, Springer, Corfu, Greece, September 1999 (inproceedings)
Abstract
Edges are viewed as statistical outliers with respect to local image gradient magnitudes. Within local image regions we compute a robust statistical measure of the gradient variation and use this in an anisotropic diffusion framework to determine a spatially varying "edge-stopping" parameter σ. We show how to determine this parameter for two edge-stopping functions described in the literature (Perona-Malik and the Tukey biweight). Smoothing of the image is related the local texture and in regions of low texture, small gradient values may be treated as edges whereas in regions of high texture, large gradient magnitudes are necessary before an edge is preserved. Intuitively these results have similarities with human perceptual phenomena such as masking and "popout". Results are shown on a variety of standard images.
#### 1999
##### Probabilistic detection and tracking of motion discontinuities
(Marr Prize, Honorable Mention)
Black, M. J., Fleet, D. J.
In Int. Conf. on Computer Vision, ICCV-99, pages: 551-558, ICCV, Corfu, Greece, September 1999 (inproceedings)
##### Explaining optical flow events with parameterized spatio-temporal models
In IEEE Proc. Computer Vision and Pattern Recognition, CVPR’99, pages: 326-332, IEEE, Fort Collins, CO, 1999 (inproceedings)
#### 1997
##### Robust anisotropic diffusion and sharpening of scalar and vector images
Black, M. J., Sapiro, G., Marimont, D., Heeger, D.
In Int. Conf. on Image Processing, ICIP, 1, pages: 263-266, Vol. 1, Santa Barbara, CA, October 1997 (inproceedings)
Abstract
Relations between anisotropic diffusion and robust statistics are described. We show that anisotropic diffusion can be seen as a robust estimation procedure that estimates a piecewise smooth image from a noisy input image. The "edge-stopping" function in the anisotropic diffusion equation is closely related to the error norm and influence function in the robust estimation framework. This connection leads to a new "edge-stopping" function based on Tukey's biweight robust estimator, that preserves sharper boundaries than previous formulations and improves the automatic stopping of the diffusion. The robust statistical interpretation also provides a means for detecting the boundaries (edges) between the piecewise smooth regions in the image. We extend the framework to vector-valued images and show applications to robust image sharpening.
#### 1997
##### Robust anisotropic diffusion: Connections between robust statistics, line processing, and anisotropic diffusion
Black, M. J., Sapiro, G., Marimont, D., Heeger, D.
In Scale-Space Theory in Computer Vision, Scale-Space’97, pages: 323-326, LNCS 1252, Springer Verlag, Utrecht, the Netherlands, July 1997 (inproceedings)
##### Learning parameterized models of image motion
Black, M. J., Yacoob, Y., Jepson, A. D., Fleet, D. J.
In IEEE Conf. on Computer Vision and Pattern Recognition, CVPR-97, pages: 561-567, Puerto Rico, June 1997 (inproceedings)
Abstract
A framework for learning parameterized models of optical flow from image sequences is presented. A class of motions is represented by a set of orthogonal basis flow fields that are computed from a training set using principal component analysis. Many complex image motions can be represented by a linear combination of a small number of these basis flows. The learned motion models may be used for optical flow estimation and for model-based recognition. For optical flow estimation we describe a robust, multi-resolution scheme for directly computing the parameters of the learned flow models from image derivatives. As examples we consider learning motion discontinuities, non-rigid motion of human mouths, and articulated human motion.
##### Analysis of gesture and action in technical talks for video indexing
Ju, S. X., Black, M. J., Minneman, S., Kimber, D.
In IEEE Conf. on Computer Vision and Pattern Recognition, pages: 595-601, CVPR-97, Puerto Rico, June 1997 (inproceedings)
Abstract
In this paper, we present an automatic system for analyzing and annotating video sequences of technical talks. Our method uses a robust motion estimation technique to detect key frames and segment the video sequence into subsequences containing a single overhead slide. The subsequences are stabilized to remove motion that occurs when the speaker adjusts their slides. Any changes remaining between frames in the stabilized sequences may be due to speaker gestures such as pointing or writing and we use active contours to automatically track these potential gestures. Given the constrained domain we define a simple vocabulary'' of actions which can easily be recognized based on the active contour shape and motion. The recognized actions provide a rich annotation of the sequence that can be used to access a condensed version of the talk from a web page.
##### Modeling appearance change in image sequences
Black, M. J., Yacoob, Y., Fleet, D. J.
In Advances in Visual Form Analysis, pages: 11-20, Proceedings of the Third International Workshop on Visual Form, Capri, Italy, May 1997 (inproceedings)
#### 1996
##### Cardboard people: A parameterized model of articulated motion
Ju, S. X., Black, M. J., Yacoob, Y.
In 2nd Int. Conf. on Automatic Face- and Gesture-Recognition, pages: 38-44, Killington, Vermont, October 1996 (inproceedings)
Abstract
We extend the work of Black and Yacoob on the tracking and recognition of human facial expressions using parameterized models of optical flow to deal with the articulated motion of human limbs. We define a "cardboard person model" in which a person's limbs are represented by a set of connected planar patches. The parameterized image motion of these patches is constrained to enforce articulated motion and is solved for directly using a robust estimation technique. The recovered motion parameters provide a rich and concise description of the activity that can be used for recognition. We propose a method for performing view-based recognition of human activities from the optical flow parameters that extends previous methods to cope with the cyclical nature of human motion. We illustrate the method with examples of tracking human legs over long image sequences.
#### 1996
##### Skin and Bones: Multi-layer, locally affine, optical flow and regularization with transparency
(Nominated: Best paper)
Ju, S., Black, M. J., Jepson, A. D.
In IEEE Conf. on Computer Vision and Pattern Recognition, CVPR’96, pages: 307-314, San Francisco, CA, June 1996 (inproceedings)
##### EigenTracking: Robust matching and tracking of articulated objects using a view-based representation
Black, M. J., Jepson, A.
In Proc. Fourth European Conf. on Computer Vision, ECCV’96, pages: 329-342, LNCS 1064, Springer Verlag, Cambridge, England, April 1996 (inproceedings)
#### 1995
##### Robust estimation of multiple surface shapes from occluded textures
Black, M. J., Rosenholtz, R.
In International Symposium on Computer Vision, pages: 485-490, Miami, FL, November 1995 (inproceedings)
#### 1995
##### The PLAYBOT Project
Tsotsos, J. K., Dickinson, S., Jenkin, M., Milios, E., Jepson, A., Down, B., Amdur, E., Stevenson, S., Black, M., Metaxas, D., Cooperstock, J., Culhane, S., Nuflo, F., Verghese, G., Wai, W., Wilkes, D., Ye, Y.
In Proc. IJCAI Workshop on AI Applications for Disabled People, Montreal, August 1995 (inproceedings)
##### Recognizing facial expressions under rigid and non-rigid facial motions using local parametric models of image motion
Black, M. J., Yacoob, Y.
In International Workshop on Automatic Face- and Gesture-Recognition, Zurich, July 1995 (inproceedings)
##### Tracking and recognizing rigid and non-rigid facial motions using local parametric models of image motion
Black, M. J., Yacoob, Y.
In Fifth International Conf. on Computer Vision, ICCV’95, pages: 347-381, Boston, MA, June 1995 (inproceedings)
Abstract
This paper explores the use of local parametrized models of image motion for recovering and recognizing the non-rigid and articulated motion of human faces. Parametric flow models (for example affine) are popular for estimating motion in rigid scenes. We observe that within local regions in space and time, such models not only accurately model non-rigid facial motions but also provide a concise description of the motion in terms of a small number of parameters. These parameters are intuitively related to the motion of facial features during facial expressions and we show how expressions such as anger, happiness, surprise, fear, disgust and sadness can be recognized from the local parametric motions in the presence of significant head motion. The motion tracking and expression recognition approach performs with high accuracy in extensive laboratory experiments involving 40 subjects as well as in television and movie sequences.
##### A computational model for shape from texture for multiple textures
Black, M. J., Rosenholtz, R.
Investigative Ophthalmology and Visual Science Supplement, Vol. 36, No. 4, pages: 2202, March 1995 (conference)
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http://forums.xkcd.com/viewtopic.php?f=17&t=68643
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## The Shortest String Containing all Permutations of n Symbols
For the discussion of math. Duh.
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NathanielJ
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### The Shortest String Containing all Permutations of n Symbols
Here's an interesting (to me, anyway) combinatorics problem that has a reasonably intuitive answer that I can't for the life of me prove is correct or find a proof of.
What is the length of the shortest string that contains every permutation of the digits 1,2,...,n as substrings?
For example, when n = 2 a minimal string is 121, which contains each of "12" and "21" as substrings. When n = 3, a minimal string is 123121321, which contains each of "123", "132", "213", "231", "312", and "321" as substrings. The length of the shortest such string has been conjectured to be equal to$\sum_{k=1}^n k!$See the OEIS, MathExchange, StackOverflow and this PDF for similar posts by people asking about this question. Strangely, these are the only sources that I can find that mention this problem, and they all are from last year. Those posts all go into how to construct a string that by all rights seems optimal, and all of those sources conjecture that the given string is indeed of minimal length, but not one of them actually proves it. And I can't seem to prove it either, despite the fact that it looks like it should fall to a simple induction argument.
So my question is -- is the conjecture true? Is the conjectured "optimal" string of length [imath]\sum_{k=1}^n k![/imath] actually optimal?
I believe the reason the conjecture is more difficult to prove than would be expected is because there seems to be some sort of shift in behaviour of the optimal strings around n = 5 or n = 6, at which point it becomes infeasible to brute force what the optimal strings are, and the strings are so long as to be difficult to work with.
For example, via brute-force you can show that for n = 1,2,3,4 the optimal string has length 1,3,9,33, follows the construction given in the posts linked above, and furthermore is unique (up to requiring that the string starts with "123...n"). However, when n = 5 there are two optimal strings that start with "12345", and when n = 6 there are at least 96 distinct strings of the conjectured minimal length.
So does anyone have any insights on this problem or any other references that I'm not aware of? Cheers.
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Charlie!
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### Re: The Shortest String Containing all Permutations of n Sym
Hm. What properties could we expect this minimal string to have? Should we expect it to have no repetitions of length n? It *cannot* satisfy the rule that each substring of length n has every character, since then it would just be repetitions of one template. Can we find some rule governing how many "invalid" substrings the shortst string must have?
Some people tell me I laugh too much. To them I say, "ha ha ha!"
NathanielJ
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### Re: The Shortest String Containing all Permutations of n Sym
Charlie! wrote:Hm. What properties could we expect this minimal string to have? Should we expect it to have no repetitions of length n? It *cannot* satisfy the rule that each substring of length n has every character, since then it would just be repetitions of one template. Can we find some rule governing how many "invalid" substrings the shortst string must have?
The shortest string seems to be the one obtained in this way (I will demonstrate the construction for n = 4, but it extends naturally for higher n):
Start with "1234" and notice that if we tack a "1" on the end then we have added another permutation with only one extra symbol. Then adding "2" gives another permutation at the cost of only one more symbol, and so on until we get "1234123". But now we can't add another permutation to the string by adding only one symbol -- we have to add two symbols. So we get "123412314". And now we can go back to adding just one symbol 3 times to get "123412314231", which contains three more permutations. And then again we have to add 2 more symbols to add another permutation. And so on.
If we continue in this way naively using this "greedy" algorithm where we just add as few symbols at a time as possible, we end up with the string "123412314231243121342132413214321", which is in fact known to be the unique optimal string for n = 4.
For n = 4, the number of symbols that you need to add to the string to get one more permutation are as follows:
1 1 1 2 1 1 1 2 1 1 1 3 1 1 1 2 1 1 1 2 1 1 1
There is a clear pattern here that is not difficult to generalize, but the difficulty is proving that this pattern is indeed optimal in general -- it could be the case (for large n) that if we increase one of the early numbers (i.e., we don't use the greedy algorithm but rather add some extra length early on), it allows us to decrease later numbers by a larger factor, thus shortening the overall string.
We can simplify this a bit even. Notice that the optimal string for n = 4 can be broken into chunks of length 2n-1 = 7 as follows:
Code: Select all
1234123142312431213421324132143211234123 2314231 3124312 2134213 1324132 3214321
Each chunk has the following two properties:
(1) The middle digit of each chunk is n (=4 in this case).
(2) The first n-1 symbols of the chunk are the same as the last n-1 symbols of the chuck (including order) and are a permutation of the symbols 1,2,...,n-1.
If we can prove that the optimal string can always be broken down into chunks of length 2n-1 that satisfy those properties, then we can prove many nice things (such as the length of the optimal strings, and even a formula for how many optimal strings there are).
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undecim
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### Re: The Shortest String Containing all Permutations of n Sym
Blue, blue, blue
skullturf
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### Re: The Shortest String Containing all Permutations of n Sym
undecim wrote:http://en.wikipedia.org/wiki/De_Bruijn_sequence
Note that this includes all words of specified length, including those where symbols are repeated.
NathanielJ
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### Re: The Shortest String Containing all Permutations of n Sym
How did I know that one of the first replies would be to the Wikipedia article on de Bruijn sequences?
The de Bruijn diagram approach doesn't work because there is no way to concatenate all of the permutations next to each other with overlap n-1 each. After you use n of the permutations, you run out of options for what the next symbol in the string should be.
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++\$_
Mo' Money
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### Re: The Shortest String Containing all Permutations of n Sym
The more general term for this kind of object is "universal sequence". (However, universal sequences are often forbidden from having repeats -- that is, each structure would have to appear exactly once in the sequence.) In general, not much is known about them, so any solution to this problem is probably worth publishing.
In a related problem, it has been proven that when n > 2, a universal cycle of length n! (that is, a universal sequence that eats its own tail) for permutations in [imath]S_n[/imath] must have at least n+1 distinct characters in its alphabet, and n+1 is achievable for all n.
silverhammermba
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### Re: The Shortest String Containing all Permutations of n Sym
NathanielJ wrote:There is a clear pattern here that is not difficult to generalize, but the difficulty is proving that this pattern is indeed optimal in general -- it could be the case (for large n) that if we increase one of the early numbers (i.e., we don't use the greedy algorithm but rather add some extra length early on), it allows us to decrease later numbers by a larger factor, thus shortening the overall string.
Perhaps if we think about the number of "uses" of each character i.e. the number of unique permutations it is part of in the sequence. The greedy algorithm tries to maximize the use of each character, whereas the naive algorithm (concatenating all permutations) minimizes the use of each character. Some usage assignments would be impossible and perhaps we could find a restriction on the assignments that would force the string to be of the desired length.
For your n=3 example (123121321), the uses we get are
123222321
which also implies a pattern. If we can find restrictions on the usage patterns, it could provide a way to show that the uses cannot be more efficiently packed.
Here are the simple restrictions I've come up with so far:
1. The number of a character's uses is less than or equal to the number of length n substrings it is contained in
2. The total uses of a string must sum to n*n!
With those restrictions alone, for n=3 we would hope to get a string with the following uses
12333321
which is one character shorter than optimal, so hopefully we could find more restrictions on uses that would force the string to meet the hypothesized optimal length.
jtillots
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### Re: The Shortest String Containing all Permutations of n Sym
I along with my math professor Dan Ashlock wrote a paper about this very topic back in 1993. We called the paper Construction of Small Superpermutations and Minimal Injective Superstrings. We found the length of the shortest strings to be the sum(k!) as k goes from 1 to n. Note there are also n! such strings since you can replace 1 with 2 and 2 with 1, etc. and still have a valid shortest string. We also found algorithms for deriving the shortest strings, but we couldn't prove that our strings were shortest. We used an exhaustive computer search to prove that the algorithm generated the shortest string up to 11, but that's as far as we went.
I've been trying for years to get a mathematician to take up this problem. I'm a computer scientist and cognitive scientist and don't know enough math to prove this. I've been told by many mathematicians that this problem is easy and they've generated the proof before, but no one can produce the proof. I think the problem is deceptively simple which causes mathematicians to blow it off.
I periodically check to see if anyone has done any research on this topic. Thanks for the post here! It made my day. I'd also be happy to send more information. I'm new to this forum, but ping me on here if you can or leave a message in this comment.
Jenett
NathanielJ
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### Re: The Shortest String Containing all Permutations of n Sym
jtillots wrote:I along with my math professor Dan Ashlock...
Oh wow that's weird -- what a small world, Dan is a professor at my university (U of Guelph). I had no idea that he had worked on this problem!
jtillots wrote:We also found algorithms for deriving the shortest strings, but we couldn't prove that our strings were shortest. We used an exhaustive computer search to prove that the algorithm generated the shortest string up to 11, but that's as far as we went.
I would be very interested in seeing the algorithm for searching the space, as I've only been able to prove optimality up to n = 6; by n = 11 things are quite huge.
jtillots wrote:I've been told by many mathematicians that this problem is easy and they've generated the proof before, but no one can produce the proof. I think the problem is deceptively simple which causes mathematicians to blow it off.
Yep, that's been my experience with the problem too. I even found one mathematics competition that contained the problem, and then the "solutions" just hand-waved it by showing that a string of that length always exists, but they didn't prove optimality.
Anyway, I would love to see any information about this problem that you have (including the paper that you co-authored with Dan ). You can e-mail me at njohns01(AT)uoguelph.ca if you don't want to post them here. Thanks, and all the best.
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jtillots
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### Re: The Shortest String Containing all Permutations of n Sym
I think I heard about that mathematics competition. I was talking to someone at a party about this problem and they told me about a math competition where this was one of the problems. I got super excited and asked what the proof was, he said, "Oh, I don't remember. But it was simple." *sigh*
I'm sorry it's taken me so long to reply to you. I don't frequent these forums very often - only when I'm looking for more info about super permutations.
I've sent you some email. I'd love to see this problem move forward.
Jenett
tomtom2357
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### Re: The Shortest String Containing all Permutations of n Sym
If these results are true, then you have an upper bound on the string, and you're conjecturing that the correct value is that upper bound. An easy lower bound is n!+n-1, but this can be improved slightly to n!+n for n>2, because after the first n symbols (which without loss of generality we can define them to be 123...n) one of the next n symbols must not make a new permutation. I am going to try to extend this in some way to make the lower bound something of the form n!+O((n-1)!).
Edit: I have found a better lower bound on the length of the optimal string. I can prove that at least n!+(n-1)!+n-2 symbols are needed, by using the argument that for every n permutations in the string, there is at least one symbol after them in the string which make the sub-string of all n symbols behind that one, including itself, not be a new permutation. The n-1 comes from the fact that the first n-1 symbols do not add any new permutations without the later symbols. The -1 comes from the fact the last permutation does not have any symbols after it, therefore there is no non-permutation sub-string ending in a symbol after that. This lower bound is exact only for n<=3, so I might have to change my line of reasoning from here.
Edit 2: I realized how I can improve my bound on the number of symbols needed. If the number of symbols used is exactly the lower bound, then there are exactly n permutations for every symbol that does not make a new permutation (not including the first n-1 symbols). Therefore, assuming that the string starts with 123...n, then we can generate the sequence. Setting n=4, and generating the sequence the way mentioned above gives 1234123142312431234..., which is clearly repetitive, and does not give every permutation. Therefore, there must be a corrective symbol in the string that makes the string non-repetitive, so the shortest string for n=4 is 33. I am working on generalizing this to give a lower bound of the form n!+(n-1)!+O((n-2)!). I can see that if I keep thinking, I can probably come up with bounds that contain arbitrarily many factorials in it, so all I need is an inductive proof to prove that the lower bound is the upper bound.
I have discovered a truly marvelous proof of this, which this margin is too narrow to contain.
PM 2Ring
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### Re: The Shortest String Containing all Permutations of n Sym
FWIW, Martin Gardner wrote about a closely related problem that used circular lists rather than linear ones. In his article, the puzzle was described in terms of different coloured beads on a bracelet. Sorry I can't remember any details, I read the article several decades ago.
EDIT: After a bit of Googling, it appears that the bracelet in Gardner's puzzle only used beads of two colours, and it contains all possible bit strings upto a certain length, so that's probably not very helpful. Oh well.
dudiobugtron
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### Re: The Shortest String Containing all Permutations of n Sym
NathanielJ wrote:it looks like it should fall to a simple induction argument.
I imagine the induction step would be something like:
Since there are (n+1)! permutations, there must be at least [size of min string for n] + (n+1)! characters in a minimal string for n+1, otherwise we could do some fancy trick and remove (n+1)! characters and have a minimal string for the digits 1,...,n, which would be a contradiction.
I haven't thought about it too much though but if I had more time that is the way I'd try to go about it.
dudiobugtron
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### Re: The Shortest String Containing all Permutations of n Sym
Yup. I think this is the outline of a viable proof, although I have made more than a few appeals to 'obviousness' which people are free to dispute!!! I've spoiler tagged it because it's a bit long and has a few sum symbols.:
Spoiler:
Base case: done, by others above.
Background:
Consider the permutations of the digits 1,...,n+1. There are (n+1)! of these. If you remove all of the digits 'n+1' from each permutation, you will end up with n+1 copies of each of the n! permutations of the digits of 1,...,n. (One copy for each of the n+1 positions the 'n+1' digit could occupy.)
Consider a string, S_(n+1), containing all (n+1)! permutations of the digits 1,...,n+1.
Each digit 'n+1' in the string can be a part of at most n+1 of these permutations (since the permutations are of length n+1), so the minimum number of 'n+1' digits in the string is (n+1)! / (n+1) = n!
If you remove all of the digits 'n+1', the string will then (as above) contain at least n+1 copies of each of the n! permutations of the digits 1,...,n.
It seems apparent that we can safely remove n.n! digits (corresponding to the n.n! extra copies) and still have all n! of the permutations of the digits 1,...,n contained in the string.
Removing these n.n! digits, along with the (at least) n! 'n+1' digits gives a total of n! + n.n! = (n+1).n! = (n+1)!
Therefore:
Lemma: Given a string S_(n+1) containing all permutations of the digits 1,...,n+1 as substrings, it is possible to remove (n+1)! digits and be left with a string which contains all of the permutations of the digits 1,...,n as substrings.
Induction step: Assume that for every string, S_n, containing every permutation of the digits 1,...,n as substrings, the length of S_n is at least:
$\sum_{k=1}^n k!$
Now, assume that there is a string, S(n+1), which contains every permutation of the digits 1,...,n+1 as substrings, and that the length of S_(n+1) is less than:
$\sum_{k=1}^{n+1} k! = \sum_{k=1}^n k! + (n+1)!$
Using the above Lemma, we can remove (n+1)! of the digits and still have a string which contains all of the permutations of the digits 1,...,n as substrings. But the length of this string is less than:
$\sum_{k=1}^n k!$
Which is a contradiction. Therefore any string, S(n+1), which contains every permutation of the digits 1,...,n+1 as substrings, must be of length at least:
$\sum_{k=1}^{n+1} k!$
/proof
CCC
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### Re: The Shortest String Containing all Permutations of n Sym
dudiobugtron wrote:If you remove all of the digits 'n+1', the string will then (as above) contain at least n+1 copies of each of the n! permutations of the digits 1,...,n.
I think that's not quite right. Consider the sequence of digits 41234. This contains two unique length-four sequences (4123 and 1234), but removing the 4s leaves us with only one copy of the base length-three sequence.
This only applies to the case where (n+1) is before and after the same sequence of every other digit; so the string as a whole will still contain at least n copies of each of the n! permutations.
tomtom2357
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### Re: The Shortest String Containing all Permutations of n Sym
CCC wrote:
dudiobugtron wrote:If you remove all of the digits 'n+1', the string will then (as above) contain at least n+1 copies of each of the n! permutations of the digits 1,...,n.
I think that's not quite right. Consider the sequence of digits 41234. This contains two unique length-four sequences (4123 and 1234), but removing the 4s leaves us with only one copy of the base length-three sequence.
This only applies to the case where (n+1) is before and after the same sequence of every other digit; so the string as a whole will still contain at least n copies of each of the n! permutations.
I think that given his assumption that the string contains all (n+1)! permutations of the digits 1 to n+1, then if you remove all the n+1's there is at least n+1 of each permutation of the digits from 1 to n. I agree with everything except:
dudiobugtron wrote:It seems apparent that we can safely remove n.n! digits (corresponding to the n.n! extra copies) and still have all n! of the permutations of the digits 1,...,n contained in the string.
Removing these n.n! digits, along with the (at least) n! 'n+1' digits gives a total of n! + n.n! = (n+1).n! = (n+1)!
If you could prove this, I would be happy with your proof.
I have discovered a truly marvelous proof of this, which this margin is too narrow to contain.
Deedlit
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### Re: The Shortest String Containing all Permutations of n Sym
tomtom2357 wrote:
CCC wrote:
dudiobugtron wrote:If you remove all of the digits 'n+1', the string will then (as above) contain at least n+1 copies of each of the n! permutations of the digits 1,...,n.
I think that's not quite right. Consider the sequence of digits 41234. This contains two unique length-four sequences (4123 and 1234), but removing the 4s leaves us with only one copy of the base length-three sequence.
This only applies to the case where (n+1) is before and after the same sequence of every other digit; so the string as a whole will still contain at least n copies of each of the n! permutations.
I think that given his assumption that the string contains all (n+1)! permutations of the digits 1 to n+1, then if you remove all the n+1's there is at least n+1 of each permutation of the digits from 1 to n.
But I think, because of CCC's objection, that statement remains unproven. There are n+1 permutations of length n+1 that collapse to the same permutation of length n, but as CCC said, two such permutations could be the same permutation when you remove n+1.
I agree with everything except:
dudiobugtron wrote:It seems apparent that we can safely remove n.n! digits (corresponding to the n.n! extra copies) and still have all n! of the permutations of the digits 1,...,n contained in the string.
Removing these n.n! digits, along with the (at least) n! 'n+1' digits gives a total of n! + n.n! = (n+1).n! = (n+1)!
If you could prove this, I would be happy with your proof.
I agree that this is a problem.
dudiobugtron
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### Re: The Shortest String Containing all Permutations of n Sym
Deedlit wrote:
tomtom2357 wrote:
CCC wrote:
dudiobugtron wrote:If you remove all of the digits 'n+1', the string will then (as above) contain at least n+1 copies of each of the n! permutations of the digits 1,...,n.
I think that's not quite right. Consider the sequence of digits 41234. This contains two unique length-four sequences (4123 and 1234), but removing the 4s leaves us with only one copy of the base length-three sequence.
This only applies to the case where (n+1) is before and after the same sequence of every other digit; so the string as a whole will still contain at least n copies of each of the n! permutations.
I think that given his assumption that the string contains all (n+1)! permutations of the digits 1 to n+1, then if you remove all the n+1's there is at least n+1 of each permutation of the digits from 1 to n.
But I think, because of CCC's objection, that statement remains unproven. There are n+1 permutations of length n+1 that collapse to the same permutation of length n, but as CCC said, two such permutations could be the same permutation when you remove n+1.
It's obvious that any two permutations which share the same n+1 digit will 'contract' to two distinct permutations like I want them to. I had been assuming that all the interesting cases were of this sort.
However, I also think CCC is right, that the issue is when you have two permutations that share all their digits except n+1. I'm thinking that these situations would be the result of 'excess' n+1 digits (ie: more than the 'n!' minimum I assumed in my 'proof'), which can be removed to compensate for the lost permutations. Also, you can really remove all occurrences of any digit you like (it doesn't have to be n+1, since the digits are all interchangible). If all of the digits had 'excess' occurrences like this, then the string probably isn't minimal. I know that's not a proof though!
tomtom2357 wrote:I agree with everything except:
dudiobugtron wrote:It seems apparent that we can safely remove n.n! digits (corresponding to the n.n! extra copies) and still have all n! of the permutations of the digits 1,...,n contained in the string.
Removing these n.n! digits, along with the (at least) n! 'n+1' digits gives a total of n! + n.n! = (n+1).n! = (n+1)!
If you could prove this, I would be happy with your proof.
Yeah I wasn't happy with that part either.
I realised after posting the proof that you don't actually have to prove that you can remove the digits, you merely have to prove that the *size* of a string which contains p more permutations than a 'minimum string' is atleast p greater. That's still not that easy either (even though it seems intuitively correct), so I'll think about it some more (unless someone beats me to it!)
CCC
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### Re: The Shortest String Containing all Permutations of n Sym
dudiobugtron wrote:It's obvious that any two permutations which share the same n+1 digit will 'contract' to two distinct permutations like I want them to. I had been assuming that all the interesting cases were of this sort.
However, I also think CCC is right, that the issue is when you have two permutations that share all their digits except n+1. I'm thinking that these situations would be the result of 'excess' n+1 digits (ie: more than the 'n!' minimum I assumed in my 'proof'), which can be removed to compensate for the lost permutations.
Hmmm. Let's take a look at the earlier-provided length-4 sequence:
123412314231243121342132413214321
In this case, (n+1)=4.
Now, there's no case where a pair of sequences share every number but 4 (the 4s are all spaced just a little too widely for that). And every number except 4 does indeed occur enough times to make up for the lost permutations. But let us consider briefly the consequence of removing the threes:
123412314231243121342132413214321
Note the sequence "34123" near the start. Let's look at the 412's after removing all the 3's:
1241214212412142124121421
There are only three such sequences, less than (n+1). (In fact, since there are only six fours, there's only three of each possible three-unique-digit sequence).
Hmmm. That sequence is... usefully repetitive. After the first eight digits, it simply repeats itself. Since it has the minimum possible number of 4s (i.e. six of them), I don't think there's any option; it does have to include at least n of every sequence, n=3, and the sequences 412 and 421 cannot use the same 4. (Similarly for the pairs (241; 142) and (214; 124)).
NathanielJ
Posts: 882
Joined: Sun Jan 13, 2008 9:04 pm UTC
### Re: The Shortest String Containing all Permutations of n Sym
Be careful when assuming that the optimal string *must* have a certain form based on the optimal strings in the n = 1, 2, 3, 4 cases. While there are indeed exactly (n-1)! instances of the digit n for those cases, and there is tons of symmetry to be found, that breaks down for n >= 5. When n = 5, I have two fundamentally different optimal strings: one that has 24 '5's and is symmetric like we would hope... and then one that has 27 '5's and isn't symmetric.
Homepage: http://www.njohnston.ca
Conway's Game of Life: http://www.conwaylife.com
dudiobugtron
Posts: 1098
Joined: Mon Jul 30, 2012 9:14 am UTC
Location: The Outlier
### Re: The Shortest String Containing all Permutations of n Sym
I've been thinking about this for a while (on-and-off!), and although I haven't gotten anywhere, I thought I'd at least share my approaches in case they help anyone else do something more useful.
The main idea I was trying was to look at the underlying string of *permutations* of n symbols, namely p_1, p_2, ..., p_(n!) , ordered by their first (and only?) appearance in the main string.
I was looking at the case where the underlying string could be partitioned into (n-1)! sets of n permutations, {p_(in),...,p_((i+1)n-1)}, where each p_(jn) differed from p_((j-1)n) by merely moving the starting symbol to the end (and of course similarly for each p_(in) and p_((i+1)n-1)). I was trying to prove that finding the 'best' way for ordering these sets of partitions was suitably analogous to finding the best way for ordering the permutations of (n-1) symbols. And also of course that such a process gave a best possible ordering for the partitions of n symbols.
Another related idea I tried, based on this idea as well:
NathanielJ wrote:For n = 4, the number of symbols that you need to add to the string to get one more permutation are as follows:
1 1 1 2 1 1 1 2 1 1 1 3 1 1 1 2 1 1 1 2 1 1 1
was to give a value to each of those permutations based on how many symbols needed to be added to put that permutation in the string. For the example above, this would be:
4 1 1 1 2 1 1 1 2 1 1 1 3 1 1 1 2 1 1 1 2 1 1 1
For n=4 and below, it is easily observable that the number of permutations where this number is 1 or greater is 4!, the number of permutations where it is 2 or greater is 3!, etc etc... ending up with 4! + 3! + 2! + 1! symbols needed.
So I guess if you could prove that a solution with this property would always be as short as possible, maybe by tying it in with the ideas above, then you'd be set.
(You can also see how this illustrates the above model (6 sets of 4 'nearby' permutations, each preceded by a bigger gap).)
Like I said, nothing concrete or necessarily useful, but on the chance that it may help someone I thought it was worth posting.
Jorel
Posts: 1
Joined: Wed Aug 27, 2014 5:01 pm UTC
### Re: The Shortest String Containing all Permutations of n Sym
I couldn't help noting that each of the optimal strings posted here is palindromic. That is to say, each can be read either from left to right or from right to left with the same result:
121
123121321
123412314231243121342132413214321
Many years of recreational mathematics lead me to suspect that this will be the case for all optimal strings of this type. Does anybody happen to know whether my hunch is correct?
Meanwhile, I have been working (on and off for the last fifteen years or so) on a similar problem, which is that of producing every n-digit permutation in base b. For example, there are four optimal strings in base two containing every possible two-digit permutation exactly once:
00110
11001
01100
10011
The main difference between my problem and the one being discussed here is that my optimal strings contain repeating digits. As base b increases, the number of possible optimal strings increases hyper-exponentially. In base 3 there are 216 possible solutions. In base ten, one of many, many solutions is the following 101-digit string:
00110221203323130443424140554535251506656463626160776757473727170887868584838281809989796959493929190
This string contains every single two-digit permutation from 00 to 99 in base ten, without repetition. (It is not pallindromic, of course, as no palindromic solution could possibly exist, for reasons that are not too difficult to work out.)
Moole
Posts: 93
Joined: Sun Jan 08, 2012 9:52 pm UTC
### Re: The Shortest String Containing all Permutations of n Sym
Well, I was googling about this a little, and I found out that the value conjectured in this thread (and elsewhere) is false. So, I guess that makes this problem even harder, since we don't even have a bound to try to prove.
Prior to knowing this, I spent some time thinking and came up with a novel way to look at the problem. I couldn't think of what to do next, but...
Spoiler:
What I'd do is to look at every occurrence of a given element. We will call this element n. For every permutation P of n-1, there must be at least one position where P immediately precedes n and one where n immediately precedes n. So, it makes sense to take the nth element and consider the string containing the n-1 preceding and succeeding elements. i.e. in 123121321, one has the substrings 12312 and 21321. Removing the middle "3" from each of these yields the tableaux
Code: Select all
12122121
Or, if we, in 123121321 swapped 2s and 3s
Code: Select all
1212112121
What we should note here is that, any two consecutive columns of the tableaux contain every permutation of 2, representing permutations of the form xx3, x3x, and 3xx. More generally, in any tableaux, any string of n-1 columns must contain every permutation of n-1 elements. We will refer to the right side of the tableaux as the rightmost n-1 elements (which succeeded the instance of the character n) and the left side as the leftmost n-1 elements (which preceded it).
Given the tableaux (in order), we can reconstruct the relevant string (less any elements not used in any permutation) just by reinserting the n into the middle of each row, and putting successive rows together (with as much overlap as possible), which means we can work with them instead of strings. Further, removal of any cell from the tableaux always decreases the length of the string - so every row must be necessary in an optimal solution.
We start by looking at a bit of a less trivial tableaux than the above. In particular, take the optimal string 412341243124132414231421342143214, make the tableaux
Code: Select all
123123124412312312132132142241231231213213214421321321
Since we only care about permutations of 3 appear in the tableaux, we can safely remove any references to "4" from the tableaux, along with any elements that would use the four in any substring of length 3 (i.e. the row "132142" can have the last two elements removed):
Code: Select all
12312312 123123121321321 123123121321321 21321321
Notice that, if a row ends with spaces, the next row starts with the same amount. This would be true of any tableaux reduced like so. More strongly, in fact, if the right side of a row is string A followed by k spaces, the left side of the next row is k spaces followed by A (since, for instance, the pair of rows "1231/1231" represents "123414231", so the "1" on the right of the first row is the same one as on the left of the second row).
Mathematical hangover (n.): The feeling one gets in the morning when they realize that that short, elementary proof of the Riemann hypothesis that they came up with at midnight the night before is, in fact, nonsense.
robinhouston
Posts: 3
Joined: Thu Feb 27, 2014 9:28 am UTC
### Re: The Shortest String Containing all Permutations of n Sym
Hello! Funny to see a link to my paper here while idly browsing the forum. It seems that lurkers like me are not allowed to post links, so you’ll have to Google for the things I wanted to link to.
The first interesting development since the main burst of activity on this thread was the discovery by Benjamin Chaffin of eight different length-153 superpermutations on five symbols, with a (machine) proof that there are no shorter ones. Nathaniel Johnston – the OP of this thread –has details on his blog.
That emboldened me to try to disprove the minimal-length conjecture for n=6, which I succeeded in doing.
I think in a way this makes our quest easier, since we can stop wasting effort trying to prove something that is not true; but it means the true picture is more complicated than some people had hoped.
I think the most obvious low-hanging fruit now is to prove (or disprove!) that length 872 is minimal for n=6. If anyone has access to a decent compute cluster, it should be pretty easy to hit it with Concorde (the TSP solver) till it breaks. The input file you need is 6.tsp in the list of ancillary files I included with the paper.
PM 2Ring
Posts: 3617
Joined: Mon Jan 26, 2009 3:19 pm UTC
Location: Mid north coast, NSW, Australia
### Re: The Shortest String Containing all Permutations of n Sym
Here's the link to the article on Robin Houston's blog.
Tackling the Minimal Superpermutation Problem
Last edited by PM 2Ring on Thu Sep 18, 2014 12:22 am UTC, edited 1 time in total.
Posts: 33
Joined: Wed Apr 21, 2010 8:33 pm UTC
### Re: The Shortest String Containing all Permutations of n Sym
Doesn't finding a short length-5 sequence automatically imply the existence of shorter sequences of length 6 and up?
robinhouston
Posts: 3
Joined: Thu Feb 27, 2014 9:28 am UTC
### Re: The Shortest String Containing all Permutations of n Sym
Doesn't finding a short length-5 sequence automatically imply the existence of shorter sequences of length 6 and up?
Indeed it would, but Ben Chaffin showed that there is no short superpermutation on 5 symbols: all the minimal ones have length 153, which is the same length as the recursively constructed one, i.e. 1! + 2! + 3! + 4! + 5!.
The existence of a shorter-than-conjectured superpermutation on 6 symbols implies that there are shorter-than-conjectured superpermutations for all n>6 too.
korona
Posts: 495
Joined: Sun Jul 04, 2010 8:40 pm UTC
### Re: The Shortest String Containing all Permutations of n Sym
I wrote a short conversion of the Hamiltonian path problem (see Robin Houston's paper on arXiv) to (Max-)SAT. The encoding uses roughly (n!)^2 variables, so it won't scale to large n but it may be possible to tackle the n = 6 case with this approach. However in order to do that we need to encode more domain specific knowledge. One starting point would be the following question: Can we remove edges with weight n from the graph without changing the weight of the minimal Hamiltonian path? Does any solution for n = 5 use such an edge?
robinhouston
Posts: 3
Joined: Thu Feb 27, 2014 9:28 am UTC
### Re: The Shortest String Containing all Permutations of n Sym
Interesting! It would be great if we could dispose of n=6, and going via SAT is a reasonable idea.
I haven’t proved it, but it seems plausible that it’s safe to remove edges of weight n. There are no known minimal superpermutations that use these. If removing them works, it would be worth trying to prove.
There is a minimal superpermutation at n=5 that uses an edge of weight 4, namely the “obvious” recursive one. The structure is like this (read down the columns):
Code: Select all
12345 25341 ... 31542 51243 ... 21534 51324 13254 3521423451 53412 31425 15423 ... 21345 15342 ... 32541 5214334512 ... 14253 54231 24315 13452 53421 32415 25413 ...45123 41235 42531 ... 43152 34521 ... 24153 54132 1432551234 12354 25314 ... 31524 45213 42135 41532 ... 43251... 23541 53142 31245 15243 52134 21354 15324 ... 3251423415 35412 ... 12453 52431 ... 13542 53241 32145 2514334152 54123 14235 24531 ... 13425 35421 ... 21453 5143241523 ... 42351 45312 43125 34251 54213 24135 14532 ...15234 ... 23514 53124 31254 42513 ... 41352 45321 4321552341 23145 35142 ... 12543 25134 ... 13524 53214 32154... 31452 51423 12435 25431 51342 13245 35241 ... 2154334125 14523 ... 24351 54312 ... 32451 52413 21435 1543241253 45231 42315 43512 ... 34215 24513 ... 14352 5432112534 52314 23154 35124 ... 42153 45132 41325 43521
In the middle there’s an edge from 54312 to 21345, which has weight 4.
On the other hand, the heaviest edge in the shortest-known superpermutation for n=6 has weight 3. If you could establish a bound even assuming all edges have weight ≤3, that would still be pretty interesting I think!
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http://mathoverflow.net/questions/67917/does-specification-implies-that-entropy-map-is-upper-semicontinuous
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# Does specification implies that entropy map is upper semicontinuous?
Let (X,d) be a compact metric space and f a continuous transformation on X. f has the specification if one can always find a single orbit to interpolate between different pieces of orbits, up to a pre-assigned error. We call the map \mu to h_{\mu}(f) (Kolmogorov-Sinai entropy)the entropy map . Does specification implies that entropy map is upper semicontinuous?
-
Your definition of specification sounds more like a definition of topological transitivity -- the key function of specification is to ensure that the time you spend going from one orbit segment to the next when you approximate is uniformly bounded. – Vaughn Climenhaga Jun 16 '11 at 11:36
This sounds a little bit like a homework exercise (my apologies if it's not). A natural thing to do would be to write down a couple examples of systems whose entropy map is not upper semi-continuous, and see if you can find something from that list with specification. – Vaughn Climenhaga Jun 16 '11 at 11:45
Hi, dear Climenhaga, thank you for your answers. – ljjpfx Jun 17 '11 at 3:08
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http://mathhelpforum.com/algebra/33343-solved-solving-variable-raised-itself.html
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# Math Help - [SOLVED] Solving a variable raised to itself
1. ## [SOLVED] Solving a variable raised to itself
I am trying to solve for k and i get to the step:
2^n=k^k
How do i deal with k raised to itself....its driving me nuts
2. ## Just to let you know
You are not supposed to double post...you can get in trouble for it...if you leave your question in one forum it will be answered eventually..
3. Originally Posted by JesseHackett
I am trying to solve for k and i get to the step:
2^n=k^k
How do i deal with k raised to itself....its driving me nuts
$k^2 = 2^n$
Solving for k, we take the square root of both sides:
$\sqrt{k^2} = \sqrt{2^n}$
$k = \pm 2^{n/2}$
EDIT: I just saw you had k raised to itself, and not 2. Disregard my post.
4. Originally Posted by JesseHackett
I am trying to solve for k and i get to the step:
2^n=k^k
How do i deal with k raised to itself....its driving me nuts
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https://indico.cern.ch/event/708041/contributions/3269754/
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# ACAT 2019
10-15 March 2019
Steinmatte conference center
Europe/Zurich timezone
## Excursion Set Estimation using Sequential Entropy Reduction for Efficient Searches for New Physics at the LHC
13 Mar 2019, 18:40
20m
Steinmatte Room A
#### Steinmatte Room A
Oral Track 2: Data Analysis - Algorithms and Tools
### Speaker
Lukas Alexander Heinrich (New York University (US))
### Description
A common goal in the search for new physics is the determination of sets of New Physics models, typically parametrized by a number of parameters such as masses or couplings, that are either compatible with the observed data or excluded by it, where the determination into which category a given model belong requires expensive computation of the expected signal. This problem may be abstracted into the generalized problem of finding excursion sets (or, equivalently, iso-surfaces) of scalar, multivariate functions in $n$ dimensions.
We present an iterative algorithm for choosing points within the problem domain for which the functions are evaluated in order to estimate such sets at a significantly lower computational cost. The algorithm implements a Bayesian Optimization procedure, in which a information-based acquisition function seeks to maximally reduce the uncertainty on a excursion set. Further extension of the basic algorithm to the simultaneous estimation of excursion sets of multiple functions as well as batched selection of multiple points is presented.
Finally, a python package, excursion[1], is presented, which implements the algorithm and performance benchmarks are presented comparing this active-learning approach to other strategies commonly used in the high energy physics context, such as random sampling and grid searches.
[1] https://github.com/diana-hep/excursion
### Primary authors
Lukas Alexander Heinrich (New York University (US)) Gilles Louppe (New York University (US)) Kyle Stuart Cranmer (New York University (US))
### Presentation Materials
ExcursionSet (1).pdf slides
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https://xianblog.wordpress.com/tag/subjective-probability/
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statistical illiteracy
Posted in Statistics with tags , , , , , , , , , , , on October 27, 2020 by xi'an
An opinion tribune in the Guardian today about the importance of statistical literacy in these COVIdays, entitled “Statistical illiteracy isn’t a niche problem. During a pandemic, it can be fatal“, by Carlo Rovelli (a physics professor on Luminy campus) which, while well-intended, is not particularly helping. For instance, the tribune starts with a story of a cluster of a rare disease happening in a lab along with the warning that [Poisson] clusters also occur with uniform sampling. But.. being knowledgeable about the Poisson process may help in reducing the psychological stress within the lab only if the cluster size is compatible with the prevalence of the disease in the neighbourhood. Obviously, a poor understanding of randomness and statistical tools has not help with the handling of the pandemics by politicians, decision-makers, civil servants and doctors (although I would have added the fundamental misconception about scientific models which led most people to confuse the map with the territory and later cry wolf…)
Rovelli also cites Bruno de Finetti as “the key to understanding probability”, as a representation of one’s beliefs rather than a real thing. While I agree with this Bayesian perspective, I am unsure it will percolate well enough with the Guardian audience. And bring more confidence in the statistical statements made by experts…
It is only when I finished reading the column that I realised it was adapted from a book soon to appear by the author. And felt slightly cheated. [Obviously, I did not read it so this is NOT a book review!]
Probability and Bayesian modeling [book review]
Posted in Books, Kids, R, Statistics, University life with tags , , , , , , , , , , , , , , , , , on March 26, 2020 by xi'an
Probability and Bayesian modeling is a textbook by Jim Albert [whose reply is included at the end of this entry] and Jingchen Hu that CRC Press sent me for review in CHANCE. (The book is also freely available in bookdown format.) The level of the textbook is definitely most introductory as it dedicates its first half on probability concepts (with no measure theory involved), meaning mostly focusing on counting and finite sample space models. The second half moves to Bayesian inference(s) with a strong reliance on JAGS for the processing of more realistic models. And R vignettes for the simplest cases (where I discovered R commands I ignored, like dplyr::mutate()!).
As a preliminary warning about my biases, I am always reserved at mixing introductions to probability theory and to (Bayesian) statistics in the same book, as I feel they should be separated to avoid confusion. As for instance between histograms and densities, or between (theoretical) expectation and (empirical) mean. I therefore fail to relate to the pace and tone adopted in the book which, in my opinion, seems to dally on overly simple examples [far too often concerned with food or baseball] while skipping over the concepts and background theory. For instance, introducing the concept of subjective probability as early as page 6 is laudable but I doubt it will engage fresh readers when describing it as a measurement of one’s “belief about the truth of an event”, then stressing that “make any kind of measurement, one needs a tool like a scale or ruler”. Overall, I have no particularly focused criticisms on the probability part except for the discrete vs continuous imbalance. (With the Poisson distribution not covered in the Discrete Distributions chapter. And the “bell curve” making a weird and unrigorous appearance there.) Galton’s board (no mention found of quincunx) could have been better exploited towards the physical definition of a prior, following Steve Stiegler’s analysis, by adding a second level. Or turned into an R coding exercise. In the continuous distributions chapter, I would have seen the cdf coming first to the pdf, rather than the opposite. And disliked the notion that a Normal distribution was supported by an histogram of (marathon) running times, i.e. values lower bounded by 122 (at the moment). Or later (in Chapter 8) for Roger Federer’s serving times. Incidentally, a fun typo on p.191, at least fun for LaTeX users, as
$f_{Y\ mid X}$
with an extra space between \’ and mid’! (I also noticed several occurrences of the unvoidable “the the” typo in the last chapters.) The simulation from a bivariate Normal distribution hidden behind a customised R function sim_binom() when it could have been easily described as a two-stage hierarchy. And no comment on the fact that a sample from Y-1.5X could be directly derived from the joint sample. (Too unconscious a statistician?)
When moving to Bayesian inference, a large section is spent on very simple models like estimating a proportion or a mean, covering both discrete and continuous priors. And strongly focusing on conjugate priors despite giving warnings that they do not necessarily reflect prior information or prior belief. With some debatable recommendation for “large” prior variances as weakly informative or (worse) for Exp(1) as a reference prior for sample precision in the linear model (p.415). But also covering Bayesian model checking either via prior predictive (hence Bayes factors) or posterior predictive (with no mention of using the data twice). A very marginalia in introducing a sufficient statistic for the Normal model. In the Normal model checking section, an estimate of the posterior density of the mean is used without (apparent) explanation.
“It is interesting to note the strong negative correlation in these parameters. If one assigned informative independent priors on and , these prior beliefs would be counter to the correlation between the two parameters observed in the data.”
For the same reasons of having to cut on mathematical validation and rigour, Chapter 9 on MCMC is not explaining why MCMC algorithms are converging outside of the finite state space case. The proposal in the algorithmic representation is chosen as a Uniform one, since larger dimension problems are handled by either Gibbs or JAGS. The recommendations about running MCMC do not include how many iterations one “should” run (or other common queries on Stack eXchange), albeit they do include the sensible running multiple chains and comparing simulated predictive samples with the actual data as a model check. However, the MCMC chapter very quickly and inevitably turns into commented JAGS code. Which I presume would require more from the students than just reading the available code. Like JAGS manual. Chapter 10 is mostly a series of examples of Bayesian hierarchical modeling, with illustrations of the shrinkage effect like the one on the book cover. Chapter 11 covers simple linear regression with some mentions of weakly informative priors, although in a BUGS spirit of using large [enough?!] variances: “If one has little information about the location of a regression parameter, then the choice of the prior guess is not that important and one chooses a large value for the prior standard deviation . So the regression intercept and slope are each assigned a Normal prior with a mean of 0 and standard deviation equal to the large value of 100.” (p.415). Regardless of the scale of y? Standardisation is covered later in the chapter (with the use of the R function scale()) as part of constructing more informative priors, although this sounds more like data-dependent priors to me in the sense that the scale and location are summarily estimated by empirical means from the data. The above quote also strikes me as potentially confusing to the students, as it does not spell at all how to design a joint distribution on the linear regression coefficients that translate the concentration of these coefficients along y̅=β⁰+β¹x̄. Chapter 12 expands the setting to multiple regression and generalised linear models, mostly consisting of examples. It however suggests using cross-validation for model checking and then advocates DIC (deviance information criterion) as “to approximate a model’s out-of-sample predictive performance” (p.463). If only because it is covered in JAGS, the definition of the criterion being relegated to the last page of the book. Chapter 13 concludes with two case studies, the (often used) Federalist Papers analysis and a baseball career hierarchical model. Which may sound far-reaching considering the modest prerequisites the book started with.
In conclusion of this rambling [lazy Sunday] review, this is not a textbook I would have the opportunity to use in Paris-Dauphine but I can easily conceive its adoption for students with limited maths exposure. As such it offers a decent entry to the use of Bayesian modelling, supported by a specific software (JAGS), and rightly stresses the call to model checking and comparison with pseudo-observations. Provided the course is reinforced with a fair amount of computer labs and projects, the book can indeed achieve to properly introduce students to Bayesian thinking. Hopefully leading them to seek more advanced courses on the topic.
Update: Jim Albert sent me the following precisions after this review got on-line:
[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Books Review section in CHANCE. As appropriate for a book about Chance!]
a concise introduction to statistical inference [book review]
Posted in Statistics with tags , , , , , , , , , , on February 16, 2017 by xi'an
[Just to warn readers and avoid emails about Xi’an plagiarising Christian!, this book was sent to me by CRC Press for a review. To be published in CHANCE.]
This is an introduction to statistical inference. And with 180 pages, it indeed is concise! I could actually stop the review at this point as a concise review of a concise introduction to statistical inference, as I do not find much originality in this introduction, intended for “mathematically sophisticated first-time student of statistics”. Although sophistication is in the eye of the sophist, of course, as this book has margin symbols in the guise of integrals to warn of section using “differential or integral calculus” and a remark that the book is still accessible without calculus… (Integral calculus as in Riemann integrals, not Lebesgue integrals, mind you!) It even includes appendices with the Greek alphabet, summation notations, and exponential/logarithms.
“In statistics we often bypass the probability model altogether and simply specify the random variable directly. In fact, there is a result (that we won’t cover in detail) that tells us that, for any random variable, we can find an appropriate probability model.” (p.17)
Given its limited mathematical requirements, the book does not get very far in the probabilistic background of statistics methods, which makes the corresponding chapter not particularly helpful as opposed to a prerequisite on probability basics. Since not much can be proven without “all that complicated stuff about for any ε>0” (p.29). And makes defining correctly notions like the Central Limit Theorem impossible. For instance, Chebychev’s inequality comes within a list of admitted results. There is no major mistake in the chapter, even though mentioning that two correlated Normal variables are jointly Normal (p.27) is inexact.
“The power of a test is the probability that you do not reject a null that is in fact correct.” (p.120)
Most of the book follows the same pattern as other textbooks at that level, covering inference on a mean and a probability, confidence intervals, hypothesis testing, p-values, and linear regression. With some words of caution about the interpretation of p-values. (And the unfortunate inversion of the interpretation of power above.) Even mentioning the Cult [of Significance] I reviewed a while ago.
Given all that, the final chapter comes as a surprise, being about Bayesian inference! Which should make me rejoice, obviously, but I remain skeptical of introducing the concept to readers with so little mathematical background. And hence a very shaky understanding of a notion like conditional distributions. (Which reminds me of repeated occurrences on X validated when newcomers hope to bypass textbooks and courses to grasp the meaning of posteriors and such. Like when asking why Bayes Theorem does not apply for expectations.) I can feel the enthusiasm of the author for this perspective and it may diffuse to some readers, but apart from being aware of the approach, I wonder how much they carry away from this brief (decent) exposure. The chapter borrows from Lee (2012, 4th edition) and from Berger (1985) for the decision-theoretic part. The limitations of the exercise are shown for hypothesis testing (or comparison) by the need to restrict the parameter space to two possible values. And for decision making. Similarly, introducing improper priors and the likelihood principle [distinguished there from the law of likelihood] is likely to get over the head of most readers and clashes with the level of the previous chapters. (And I do not think this is the most efficient way to argue in favour of a Bayesian approach to the problem of statistical inference: I have now dropped all references to the likelihood principle from my lectures. Not because of the controversy, but simply because the students do not get it.) By the end of the chapter, it is unclear a neophyte would be able to spell out how one could specify a prior for one of the problems processed in the earlier chapters. The appendix on de Finetti’s formalism on personal probabilities is very much unlikely to help in this regard. While it sounds so far beyond the level of the remainder of the book.
on de Finetti’s instrumentalist philosophy of probability
Posted in Books, Statistics, Travel, University life with tags , , , , , , , , on January 5, 2016 by xi'an
On Wednesday January 6, there is a conference in Paris [10:30, IHPST, 13, rue du Four, Paris 6] by Joseph Berkovitz (University of Toronto) on the philosophy of probability of Bruno de Finetti. Too bad this is during MCMSkv!
De Finetti is one of the founding fathers of the modern theory of subjective probability, where probabilities are coherent degrees of belief. De Finetti held that probabilities are inherently subjective and he argued that none of the objective interpretations of probability makes sense. While his theory has been influential in science and philosophy, it has encountered various objections. In particular, it has been argued that de Finetti’s concept of probability is too permissive, licensing degrees of belief that we would normally call imprudent. Further, de Finetti is commonly conceived as giving an operational, behaviorist definition of degrees of belief and accordingly of probability. Thus, the theory is said to inherit the difficulties embodied in operationalism and behaviorism. We argue that these and some other objections to de Finetti’s theory are unfounded as they overlook various central aspects of de Finetti’s philosophy of probability. We then propose a new interpretation of de Finetti’s theory that highlights these central aspects and explains how they are an integral part of de Finetti’s instrumentalist philosophy of probability. Building on this interpretation of de Finetti’s theory, we draw some lessons for the realist-instrumentalist controversy about the nature of science.
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https://www.techtud.com/chapter/12200/12203/25201
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##### Matrix Chain Multiplication | Dynamic Programming
Content covered:
Matrix chain multiplication is an optimization problem that can be solved using dynamic programming. Given a sequence of matrices, the goal is to find the most efficient way to multiply these matrices. The problem is not actually to perform the multiplications, but merely to decide the sequence of the matrix multiplications involved.
Here are many options because matrix multiplication is associative. In other words, no matter how the product is parenthesized, the result obtained will remain the same. For example, for four matrices A, B, C, and D, we would have:
((AB)C)D = ((A(BC))D) = (AB)(CD) = A((BC)D) = A(B(CD)).
However, the order in which the product is parenthesized affects the number of simple arithmetic operations needed to compute the product, or the efficiency.
For example,
if A is a 10 × 30 matrix, B is a 30 × 5 matrix, and C is a 5 × 60 matrix, then computing (AB)C needs (10×30×5) + (10×5×60) = 1500 + 3000 = 4500 operations, while computing A(BC) needs (30×5×60) + (10×30×60) = 9000 + 18000 = 27000 operations.
Clearly the first method is more efficient. With this information, the problem statement can be refined as "how to determine the optimal parenthesization of a product of n matrices?" Checking each possible parenthesization (brute force) would require a run-time that is exponential in the number of matrices, which is very slow and impractical for large n. A quicker solution to this problem can be achieved by breaking up the problem into a set of related subproblems. By solving subproblems once and reusing the solutions, the required run-time can drastically reduced.
The following bottom-up approach [1] computes, for each 2 ≤ k ≤ n, the minimum costs of all subsequences of length k, using the costs of smaller subsequences already computed. It has the same asymptotic runtime and requires no recursion.
Pseudocode:
// Matrix A[i] has dimension dims[i-1] x dims[i] for i = 1..n
MatrixChainOrder(int dims[])
{
// length[dims] = n + 1
n = dims.length - 1;
// m[i,j] = Minimum number of scalar multiplications (i.e., cost)
// needed to compute the matrix A[i]A[i+1]...A[j] = A[i..j]
// The cost is zero when multiplying one matrix
for (i = 1; i <= n; i++)
m[i, i] = 0;
for (len = 2; len <= n; len++) { // Subsequence lengths
for (i = 1; i <= n - len + 1; i++) {
j = i + len - 1;
m[i, j] = MAXINT;
for (k = i; k <= j - 1; k++) {
cost = m[i, k] + m[k+1, j] + dims[i-1]*dims[k]*dims[j];
if (cost < m[i, j]) {
m[i, j] = cost;
s[i, j] = k; // Index of the subsequence split that achieved minimal cost
}
}
}
}
}
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https://wwwopt.mathematik.tu-darmstadt.de/publications/?key=Pfaff2015&bib=all.bib
|
Publications
Reference:
Pfaff, Sebastian: "Optimal Control of Hyperbolic Conservation Laws on Bounded Domains with Switching Controls", Dr. Hut Verlag, 2015.
Bibtex Entry:
@Book{Pfaff2015,
Title = {{Optimal Control of Hyperbolic Conservation Laws on Bounded Domains with Switching Controls}},
Author = {Sebastian Pfaff},
Publisher = {Dr. Hut Verlag},
Year = {2015},
}
|
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http://en.wikipedia.org/wiki/Maximum_Zero-Fuel_Weight
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# Zero-fuel weight
(Redirected from Maximum Zero-Fuel Weight)
The zero fuel weight (ZFW) of an aircraft is the total weight of the airplane and all its contents, minus the total weight of the usable fuel on board (unusable fuel is included in ZFW).
For example, if an aircraft is flying at a weight of 5,000 kg and the weight of fuel on board is 500 kg, the ZFW is 4,500 kg. Some time later, after 100 kg of fuel has been used, the total weight of the airplane is 4,900 kg, the weight of fuel is 400 kg, and the ZFW is unchanged at 4,500 kg.
As a flight progresses and fuel is consumed, the total weight of the airplane reduces, but the ZFW remains constant (unless some part of the load, such as parachutists or stores, is jettisoned in flight).
For many types of airplane, the airworthiness limitations include a maximum zero fuel weight.
## Maximum zero fuel weight
The maximum zero fuel weight (MZFW) is the maximum weight allowed before usable fuel and other specified usable agents (engine injection fluid, and other consumable propulsion agents) are loaded in defined sections of the aircraft as limited by strength and airworthiness requirements. It may include usable fuel in specified tanks when carried in lieu of payload. The addition of usable and consumable items to the zero fuel weight must be in accordance with the applicable government regulations so that airplane structure and airworthiness requirements are not exceeded.
### Maximum zero fuel weight in aircraft operations
When an aircraft is being loaded with crew, passengers, baggage and freight it is most important to ensure that the ZFW does not exceed the MZFW. When an aircraft is being loaded with fuel it is most important to ensure that the takeoff weight will not exceed the maximum permissible takeoff weight.
MZFW : The maximum weight of an aircraft prior to fuel being loaded.
$ZFW + FOB = TOW$
For any aircraft with a defined MZFW, the maximum payload can be calculated as the MZFW minus the OEW (operational empty weight)
$Max Payload = MZFW - OEW$
## Wing bending relief
In fixed-wing aircraft, fuel is usually carried in the wings. Weight in the wings does not contribute as significantly to the bending moment in the wing as does weight in the fuselage. This is because the lift on the wings and the weight of the fuselage bend the wing tips upwards and the wing roots downwards; but the weight of the wing, including the weight of fuel in the wing, bend the wing tips downwards, providing relief to the bending effect on the wing.
When an airplane is being loaded, the capacity for extra weight in the wing is greater than the capacity for extra weight in the fuselage. Designers of airplanes can optimise the maximum takeoff weight and prevent overloading in the fuselage by specifying a MZFW. This is usually done for large airplanes.
Most small airplanes do not have a MZFW specified among their limitations. For these airplanes, the loading case that must be considered when determining the maximum takeoff weight is the airplane with zero fuel and all disposable load in the fuselage. With zero fuel in the wing the only wing bending relief is due to the weight of the wing.
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https://arxiv.org/abs/1105.1338
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### Current browse context:
cond-mat.mes-hall
(what is this?)
# Title: Decoherence-assisted initialization of a resident hole spin polarization in a two-dimensional hole gas
Abstract: We investigate spin dynamics of resident holes in a p-modulation-doped GaAs/Al$_{0.3}$Ga$_{0.7}$As single quantum well. Time-resolved Faraday and Kerr rotation, as well as resonant spin amplification, are utilized in our study. We observe that nonresonant or high power optical pumping leads to a resident hole spin polarization with opposite sign with respect to the optically oriented carriers, while low power resonant optical pumping only leads to a resident hole spin polarization if a sufficient in-plane magnetic field is applied. The competition between two different processes of spin orientation strongly modifies the shape of resonant spin amplification traces. Calculations of the spin dynamics in the electron--hole system are in good agreement with the experimental Kerr rotation and resonant spin amplification traces and allow us to determine the hole spin polarization within the sample after optical orientation, as well as to extract quantitative information about spin dephasing processes at various stages of the evolution.
Comments: 10 pages, 6 figures; moderate modifications, one new figure Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Journal reference: Phys. Rev. B 84, 085327 (2011) DOI: 10.1103/PhysRevB.84.085327 Cite as: arXiv:1105.1338 [cond-mat.mes-hall] (or arXiv:1105.1338v2 [cond-mat.mes-hall] for this version)
## Submission history
From: Paweł Machnikowski [view email]
[v1] Fri, 6 May 2011 17:44:06 GMT (483kb,D)
[v2] Thu, 19 Jan 2012 14:10:54 GMT (166kb)
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https://proceedings.neurips.cc/paper/2020/file/92bf5e6240737e0326ea59846a83e076-MetaReview.html
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NeurIPS 2020
### Meta Review
The four reviewers, all of whom are seasoned domain experts, consistently agree that this paper is conceptually solid, timely and relevant. I should thus be accepted. The reviewers also pointed out some issues with the presentation. I want to strongly encourage the authors to take these into account to increase the potential audience of this paper.
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http://math.stackexchange.com/questions/89563/are-there-infinitely-many-mersenne-primes
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# Are there infinitely many Mersenne primes?
known facts :
$1.$ There are infinitely many Mersenne numbers : $M_p=2^p-1$
$2.$ Every Mersenne number greater than $7$ is of the form : $6k\cdot p +1$ , where $k$ is an odd number
$3.$ There are infinitely many prime numbers of the form $6n+1$ , where $n$ is an odd number
$4.$ If $p$ is prime number of the form $4k+3$ and if $2p+1$ is prime number then $M_p$ is composite
What else one can include in this list above in order to prove (or disprove) that there are infinitely many Mersenne primes ?
-
Do you know about the LPW conjecture? – Guess who it is. Dec 8 '11 at 8:18
@J.M.,Interesting,but it isn't fact,it is conjecture... – pedja Dec 8 '11 at 8:21
As far as I know, this is still an open problem. – InterestedGuest Dec 8 '11 at 8:23
Clearly, you missed the point. There's a reason why the infinitude of Mersenne primes remains a conjecture. – Guess who it is. Dec 8 '11 at 8:30
No, he's saying we don't know. – JSchlather Dec 8 '11 at 8:41
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http://aeciosantos.com/2012/09/04/custom-latex-beamer-theme/
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# Aécio Santos
Just another personal web site.
September 4, 2012
# A simple & clean Latex Beamer theme
Beamer is a great Latex class used to create presentations. Unfortunately, most default Beamer themes are very bloated and full of stuff that waste the usefull space of the slides. Looking for simplicity, I created a custom beamer theme that is simple and clean.
If you already know latex and beamer, it’s pretty easy to use it. Just download the file style.tex and put it on the same folder of you latex document. Then, you just need to include the file using the command \input{style.tex} at the begining of your latex document. The structure of your document should look like this:
\documentclass[t,14pt,mathserif]{beamer}
\input{style.tex}
\title{Presentation Title}
\author{Author Name}
\begin{document}
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https://www.ekjo.org/journal/view.php?number=1484&viewtype=pubreader
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# Eyelid Schwannoma Mimicking Eyelid Amelanotic Nevus
## Article information
Korean J Ophthalmol. 2019;33(5):478-480
Publication date (electronic) : 2019 October 04
doi : https://doi.org/10.3341/kjo.2018.0123
1Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
2Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea
3Department of Ophthalmology, Seoul National University Boramae Hospital, Seoul, Korea
Corresponding Author: Namju Kim. Department of Ophthalmology, Seoul National University Bundang Hospital, Seongnam, Korea. [email protected]
Dear Editor,
Schwannoma is a benign peripheral nerve sheath tumor that frequently occurs in the orbit. However, an eyelid schwannoma is extremely rare [1], and only 20 cases have been reported. We report four cases of eyelid schwannoma and describe their common features.
A 47-year-old man presented with a lower eyelid mass of the left eye for two years. The mass measured 6 mm × 3 mm, and it was not cystic, was non-pigmented, and without tenderness or erythema. The cilia on the surface of the mass were preserved (Fig. 1A). Shaving excisional biopsy revealed well-circumscribed elongated spindle cells forming palisades with strong S-100 positivity, consistent with eyelid schwannoma (Fig. 1B, 1C).
### Clinical and histological appearance of eyelid schwannoma. (A) Case 1: Eyelid mass on the left lower eyelid. (B) Case 1: Well-circumscribed, elongated spindle cells formed palisades, consistent with Antoni type A tissue (hematoxylin and eosin [H&E], ×200). (C) Case 1: Strong reactivity for S-100 protein. (D) Case 2: Eyelid mass on the left lower eyelid. (E) Case 2: Spindle cells formed palisades, consistent with Antoni type A tissue (H&E, ×200). (F) Case 3: Eyelid mass on the left upper eyelid. (G) Case 3: Compact arrangements of spindle cells with Verocay bodies forming palisades, consistent with Antoni type A tissue (H&E, ×200). (H) Case 3: Intense positive staining with S-100 protein. (I) Case 4: Eyelid mass on the right upper eyelid. (J) Spindle cells with palisading pattern, consistent with Antoni type A tissue (H&E, ×200).
A 36-year-old woman was referred for evaluation of a lower eyelid mass of the left eye that had persisted for one year. Located on muco-cutaneous junction just above the cilia line, the mass measured 1.5 mm × 2.5 mm and was solid and amelanotic without inflammation (Fig. 1D). Shaving excisional biopsy demonstrated spindle cells forming a palisading pattern and a hyper/hypocellular area, consistent with eyelid schwannoma (Fig. 1E).
A 60-year-old woman presented with a lateral upper eyelid mass of the left eye. The 3 mm × 3 mm-sized mass was painless, non-pigmented and solid (Fig. 1F). A shaving excisional biopsy was performed, revealing spindle cells forming a palisading pattern and a Verocay body. Hyper/hypocellular area were also found with S-100 positivity, consistent with eyelid schwannoma (Fig. 1G, 1H). This patient has been previously reported [2].
A 45-year-old man was referred for a lateral upper eyelid mass of the right eye lasting for two years. A 5 mm × 3 mm-sized, solid, amelanotic mass without tenderness was observed (Fig. 1I). Shaving excisional biopsy revealed spindle cells with a palisading pattern and a hyper/hypocellular area, consistent with eyelid schwannoma (Fig. 1J).
We reported four cases of eyelid schwannoma, and each case demonstrated common features of this benign tumor: solid, non-pigmented mass with a smooth surface. Schwannoma similar to other benign eyelid tumors, such as the epidermal inclusion cyst, amelanotic nevus and chalazion [1]. However, the eyelid schwannoma differs from these conditions in that the epidermal inclusion cyst is cystic and often has a central pore [3] and the chalazion shows focal inflammatory signs [4].
The most distinguishing pathologic feature of schwannoma is reactivity to S-100, a protein only expressed in the central nervous system, Schwann cell and melanocyte [2].
The presence of multiple schwannomas is related to neurofibromatosis, although there is no relationship with neurofibromatosis for a solitary schwannoma [5]. All four cases in the present report had no relationship with neurofibromatosis. Although malignant transformation has not been reported, schwannomas should be biopsied and completely excised with a negative margin to prevent recurrence with more aggressive behaviors.
In conclusion, we reported four cases of eyelid schwannoma. Eyelid schwannoma should be considered as one of the differential diagnoses when a non-pigmented solid eyelid mass with a smooth surface is encountered.
## Notes
Conflict of Interest: No potential conflict of interest relevant to this article was reported.
## References
1. Siddiqui MA, Leslie T, Scott C, Mackenzie J. Eyelid schwannoma in a male adult. Clin Exp Ophthalmol 2005;33:412–413. 16033357.
2. Lee KW, Lee MJ, Kim NJ, et al. A case of eyelid schwannoma. J Korean Ophthalmol Soc 2009;50:290–293.
3. Foster JA, Carter KD, Durairaj VD, et al. Orbit, eyelids, and lacrimal system San Francisco: American Academy of Ophthalmology; 2015. p. 168.
4. Gerstenblith AT, Rabinowitz MP. The Wills eye manual: office and emergency room diagnosis and treatment of eye disease Philadelphia: Lippincott Williams & Wilkins; 2012. p. 137.
5. Lopez-Tizon E, Mencia-Gutierrez E, Gutierrez-Diaz E, Ricoy JR. Schwannoma of the eyelid: report of two cases. Dermatol Online J 2007;13:12.
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https://par.nsf.gov/biblio/10347071
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Experimental verification of the Landau–Lifshitz equation
Abstract The Landau–Lifshitz (LL) equation has been proposed as the classical equation to describe the dynamics of a charged particle in a strong electromagnetic field when influenced by radiation reaction. Until recently, there has been no clear experimental verification. However, aligned crystals have remedied the situation: here, as in Nielsen et al CERN NA63 Collaboration (2020 Phys. Rev. D 102 052004), we report on a quantitative experimental test of the LL equation by measuring the emission spectra of electrons and positrons penetrating aligned single crystals. The recorded spectra are in remarkable agreement with simulations based on the LL equation of motion with moderate quantum corrections for recoil and, in the case of electrons in axially aligned crystals, spin and reduced radiation intensity.
Authors:
; ; ; ;
Award ID(s):
Publication Date:
NSF-PAR ID:
10347071
Journal Name:
New Journal of Physics
Volume:
23
Issue:
8
Page Range or eLocation-ID:
085001
ISSN:
1367-2630
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http://vision.lbl.gov/People/qyang/qt_doc/qstring.html
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Home | All Classes | Main Classes | Annotated | Grouped Classes | Functions
# QString Class Reference
The QString class provides an abstraction of Unicode text and the classic C '\0'-terminated char array. More...
All the functions in this class are reentrant when Qt is built with thread support.
#include <qstring.h>
## Public Members
• QString ( QChar ch )
• QString ( const QString & s )
• QString ( const QByteArray & ba )
• QString ( const QChar * unicode, uint length )
• QString ( const char * str )
• QString ( const std::string & str )
• QString & operator= ( const QString & s )
• QString & operator= ( const char * str )
• QString & operator= ( const std::string & s )
• QString & operator= ( const QCString & cstr )
• QString & operator= ( QChar c )
• QString & operator= ( char c )
• bool isNull () const
• bool isEmpty () const
• uint length () const
• void truncate ( uint newLen )
• QString & fill ( QChar c, int len = -1 )
• QString copy () const (obsolete)
• QString arg ( long a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( ulong a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( Q_LLONG a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( Q_ULLONG a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( int a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( uint a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( short a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( ushort a, int fieldWidth = 0, int base = 10 ) const
• QString arg ( double a, int fieldWidth = 0, char fmt = 'g', int prec = -1 ) const
• QString arg ( char a, int fieldWidth = 0 ) const
• QString arg ( QChar a, int fieldWidth = 0 ) const
• QString arg ( const QString & a, int fieldWidth = 0 ) const
• QString arg ( const QString & a1, const QString & a2 ) const
• QString arg ( const QString & a1, const QString & a2, const QString & a3 ) const
• QString arg ( const QString & a1, const QString & a2, const QString & a3, const QString & a4 ) const
• QString & sprintf ( const char * cformat, ... )
• int find ( QChar c, int index = 0, bool cs = TRUE ) const
• int find ( char c, int index = 0, bool cs = TRUE ) const
• int find ( const QString & str, int index = 0, bool cs = TRUE ) const
• int find ( const QRegExp & rx, int index = 0 ) const
• int find ( const char * str, int index = 0 ) const
• int findRev ( QChar c, int index = -1, bool cs = TRUE ) const
• int findRev ( char c, int index = -1, bool cs = TRUE ) const
• int findRev ( const QString & str, int index = -1, bool cs = TRUE ) const
• int findRev ( const QRegExp & rx, int index = -1 ) const
• int findRev ( const char * str, int index = -1 ) const
• int contains ( QChar c, bool cs = TRUE ) const
• int contains ( char c, bool cs = TRUE ) const
• int contains ( const char * str, bool cs = TRUE ) const
• int contains ( const QString & str, bool cs = TRUE ) const
• int contains ( const QRegExp & rx ) const
• enum SectionFlags { SectionDefault = 0x00, SectionSkipEmpty = 0x01, SectionIncludeLeadingSep = 0x02, SectionIncludeTrailingSep = 0x04, SectionCaseInsensitiveSeps = 0x08 }
• QString section ( QChar sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
• QString section ( char sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
• QString section ( const char * sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
• QString section ( const QString & sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
• QString section ( const QRegExp & reg, int start, int end = 0xffffffff, int flags = SectionDefault ) const
• QString left ( uint len ) const
• QString right ( uint len ) const
• QString mid ( uint index, uint len = 0xffffffff ) const
• QString leftJustify ( uint width, QChar fill = ' ', bool truncate = FALSE ) const
• QString rightJustify ( uint width, QChar fill = ' ', bool truncate = FALSE ) const
• QString lower () const
• QString upper () const
• QString stripWhiteSpace () const
• QString simplifyWhiteSpace () const
• QString & insert ( uint index, const QString & s )
• QString & insert ( uint index, const QByteArray & s )
• QString & insert ( uint index, const char * s )
• QString & insert ( uint index, const QChar * s, uint len )
• QString & insert ( uint index, QChar c )
• QString & insert ( uint index, char c )
• QString & append ( char ch )
• QString & append ( QChar ch )
• QString & append ( const QString & str )
• QString & append ( const QByteArray & str )
• QString & append ( const char * str )
• QString & append ( const std::string & str )
• QString & prepend ( char ch )
• QString & prepend ( QChar ch )
• QString & prepend ( const QString & s )
• QString & prepend ( const QByteArray & s )
• QString & prepend ( const char * s )
• QString & prepend ( const std::string & s )
• QString & remove ( uint index, uint len )
• QString & remove ( const QString & str, bool cs = TRUE )
• QString & remove ( QChar c )
• QString & remove ( char c )
• QString & remove ( const char * str )
• QString & remove ( const QRegExp & rx )
• QString & replace ( uint index, uint len, const QString & s )
• QString & replace ( uint index, uint len, const QChar * s, uint slen )
• QString & replace ( uint index, uint len, QChar c )
• QString & replace ( uint index, uint len, char c )
• QString & replace ( QChar c, const QString & after, bool cs = TRUE )
• QString & replace ( char c, const QString & after, bool cs = TRUE )
• QString & replace ( const QString & before, const QString & after, bool cs = TRUE )
• QString & replace ( const QRegExp & rx, const QString & after )
• QString & replace ( QChar c1, QChar c2 )
• short toShort ( bool * ok = 0, int base = 10 ) const
• ushort toUShort ( bool * ok = 0, int base = 10 ) const
• int toInt ( bool * ok = 0, int base = 10 ) const
• uint toUInt ( bool * ok = 0, int base = 10 ) const
• long toLong ( bool * ok = 0, int base = 10 ) const
• ulong toULong ( bool * ok = 0, int base = 10 ) const
• Q_LLONG toLongLong ( bool * ok = 0, int base = 10 ) const
• Q_ULLONG toULongLong ( bool * ok = 0, int base = 10 ) const
• float toFloat ( bool * ok = 0 ) const
• double toDouble ( bool * ok = 0 ) const
• QString & setNum ( short n, int base = 10 )
• QString & setNum ( ushort n, int base = 10 )
• QString & setNum ( int n, int base = 10 )
• QString & setNum ( uint n, int base = 10 )
• QString & setNum ( long n, int base = 10 )
• QString & setNum ( ulong n, int base = 10 )
• QString & setNum ( Q_LLONG n, int base = 10 )
• QString & setNum ( Q_ULLONG n, int base = 10 )
• QString & setNum ( float n, char f = 'g', int prec = 6 )
• QString & setNum ( double n, char f = 'g', int prec = 6 )
• void setExpand ( uint index, QChar c ) (obsolete)
• QString & operator+= ( const QString & str )
• QString & operator+= ( const QByteArray & str )
• QString & operator+= ( const char * str )
• QString & operator+= ( const std::string & str )
• QString & operator+= ( QChar c )
• QString & operator+= ( char c )
• QChar at ( uint i ) const
• QChar operator[] ( int i ) const
• QCharRef at ( uint i )
• QCharRef operator[] ( int i )
• QChar constref ( uint i ) const
• QChar & ref ( uint i )
• const QChar * unicode () const
• const char * ascii () const
• const char * latin1 () const
• QCString utf8 () const
• QCString local8Bit () const
• bool operator! () const
• const unsigned short * ucs2 () const
• QString & setUnicode ( const QChar * unicode, uint len )
• QString & setUnicodeCodes ( const ushort * unicode_as_ushorts, uint len )
• QString & setAscii ( const char * str, int len = -1 )
• QString & setLatin1 ( const char * str, int len = -1 )
• int compare ( const QString & s ) const
• int localeAwareCompare ( const QString & s ) const
• void compose ()
• const char * data () const (obsolete)
• bool startsWith ( const QString & s, bool cs = TRUE ) const
• bool endsWith ( const QString & s, bool cs = TRUE ) const
• void setLength ( uint newLen )
• uint capacity () const
• void reserve ( uint minCapacity )
• void squeeze ()
## Static Public Members
• QString number ( long n, int base = 10 )
• QString number ( ulong n, int base = 10 )
• QString number ( Q_LLONG n, int base = 10 )
• QString number ( Q_ULLONG n, int base = 10 )
• QString number ( int n, int base = 10 )
• QString number ( uint n, int base = 10 )
• QString number ( double n, char f = 'g', int prec = 6 )
• QString fromAscii ( const char * ascii, int len = -1 )
• QString fromLatin1 ( const char * chars, int len = -1 )
• QString fromUtf8 ( const char * utf8, int len = -1 )
• QString fromLocal8Bit ( const char * local8Bit, int len = -1 )
• QString fromUcs2 ( const unsigned short * str )
• int compare ( const QString & s1, const QString & s2 )
• int localeAwareCompare ( const QString & s1, const QString & s2 )
## Related Functions
• bool operator== ( const QString & s1, const QString & s2 )
• bool operator== ( const QString & s1, const char * s2 )
• bool operator== ( const char * s1, const QString & s2 )
• bool operator!= ( const QString & s1, const QString & s2 )
• bool operator!= ( const QString & s1, const char * s2 )
• bool operator!= ( const char * s1, const QString & s2 )
• bool operator< ( const QString & s1, const char * s2 )
• bool operator< ( const char * s1, const QString & s2 )
• bool operator<= ( const QString & s1, const char * s2 )
• bool operator<= ( const char * s1, const QString & s2 )
• bool operator> ( const QString & s1, const char * s2 )
• bool operator> ( const char * s1, const QString & s2 )
• bool operator>= ( const QString & s1, const char * s2 )
• bool operator>= ( const char * s1, const QString & s2 )
• const QString operator+ ( const QString & s1, const QString & s2 )
• const QString operator+ ( const QString & s1, const char * s2 )
• const QString operator+ ( const char * s1, const QString & s2 )
• const QString operator+ ( const QString & s, char c )
• const QString operator+ ( char c, const QString & s )
• QDataStream & operator<< ( QDataStream & s, const QString & str )
• QDataStream & operator>> ( QDataStream & s, QString & str )
## Detailed Description
The QString class provides an abstraction of Unicode text and the classic C '\0'-terminated char array.
QString uses implicit sharing, which makes it very efficient and easy to use.
In all of the QString methods that take const char * parameters, the const char * is interpreted as a classic C-style '\0'-terminated ASCII string. It is legal for the const char * parameter to be 0. If the const char * is not '\0'-terminated, the results are undefined. Functions that copy classic C strings into a QString will not copy the terminating '\0' character. The QChar array of the QString (as returned by unicode()) is generally not terminated by a '\0'. If you need to pass a QString to a function that requires a C '\0'-terminated string use latin1().
A QString that has not been assigned to anything is null, i.e. both the length and data pointer is 0. A QString that references the empty string ("", a single '\0' char) is empty. Both null and empty QStrings are legal parameters to the methods. Assigning (const char *) 0 to QString gives a null QString. For convenience, QString::null is a null QString. When sorting, empty strings come first, followed by non-empty strings, followed by null strings. We recommend using if ( !str.isNull() ) to check for a non-null string rather than if ( !str ); see operator!() for an explanation.
Note that if you find that you are mixing usage of QCString, QString, and QByteArray, this causes lots of unnecessary copying and might indicate that the true nature of the data you are dealing with is uncertain. If the data is '\0'-terminated 8-bit data, use QCString; if it is unterminated (i.e. contains '\0's) 8-bit data, use QByteArray; if it is text, use QString.
Lists of strings are handled by the QStringList class. You can split a string into a list of strings using QStringList::split(), and join a list of strings into a single string with an optional separator using QStringList::join(). You can obtain a list of strings from a string list that contain a particular substring or that match a particular regex using QStringList::grep().
Note for C programmers
Due to C++'s type system and the fact that QString is implicitly shared, QStrings may be treated like ints or other simple base types. For example:
QString boolToString( bool b )
{
QString result;
if ( b )
result = "True";
else
result = "False";
return result;
}
The variable, result, is an auto variable allocated on the stack. When return is called, because we're returning by value, The copy constructor is called and a copy of the string is returned. (No actual copying takes place thanks to the implicit sharing, see below.)
Throughout Qt's source code you will encounter QString usages like this:
QString func( const QString& input )
{
QString output = input;
// process output
return output;
}
The 'copying' of input to output is almost as fast as copying a pointer because behind the scenes copying is achieved by incrementing a reference count. QString (like all Qt's implicitly shared classes) operates on a copy-on-write basis, only copying if an instance is actually changed.
If you wish to create a deep copy of a QString without losing any Unicode information then you should use QDeepCopy.
## Member Type Documentation
### QString::SectionFlags
• QString::SectionDefault - Empty fields are counted, leading and trailing separators are not included, and the separator is compared case sensitively.
• QString::SectionSkipEmpty - Treat empty fields as if they don't exist, i.e. they are not considered as far as start and end are concerned.
• QString::SectionIncludeLeadingSep - Include the leading separator (if any) in the result string.
• QString::SectionIncludeTrailingSep - Include the trailing separator (if any) in the result string.
• QString::SectionCaseInsensitiveSeps - Compare the separator case-insensitively.
Any of the last four values can be OR-ed together to form a flag.
## Member Function Documentation
### QString::QString ()
Constructs a null string, i.e. both the length and data pointer are 0.
### QString::QString ( QChar ch )
Constructs a string of length one, containing the character ch.
### QString::QString ( const QString & s )
Constructs an implicitly shared copy of s. This is very fast since it only involves incrementing a reference count.
### QString::QString ( const QByteArray & ba )
Constructs a string that is a deep copy of ba interpreted as a classic C string.
### QString::QString ( const QChar * unicode, uint length )
Constructs a string that is a deep copy of the first length characters in the QChar array.
If unicode and length are 0, then a null string is created.
If only unicode is 0, the string is empty but has length characters of space preallocated: QString expands automatically anyway, but this may speed up some cases a little. We recommend using the plain constructor and setLength() for this purpose since it will result in more readable code.
### QString::QString ( const char * str )
Constructs a string that is a deep copy of str, interpreted as a classic C string.
If str is 0, then a null string is created.
This is a cast constructor, but it is perfectly safe: converting a Latin-1 const char * to QString preserves all the information. You can disable this constructor by defining QT_NO_CAST_ASCII when you compile your applications. You can also make QString objects by using setLatin1(), fromLatin1(), fromLocal8Bit(), and fromUtf8(). Or whatever encoding is appropriate for the 8-bit data you have.
### QString::QString ( const std::string & str )
Constructs a string that is a deep copy of str.
This is the same as fromAscii(str).
### QString::~QString ()
Destroys the string and frees the string's data if this is the last reference to the string.
### QString & QString::append ( const QString & str )
Appends str to the string and returns a reference to the result.
string = "Test";
string.append( "ing" ); // string == "Testing"
Equivalent to operator+=().
Example: dirview/dirview.cpp.
### QString & QString::append ( char ch )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends character ch to the string and returns a reference to the result.
Equivalent to operator+=().
### QString & QString::append ( QChar ch )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends character ch to the string and returns a reference to the result.
Equivalent to operator+=().
### QString & QString::append ( const QByteArray & str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the result.
Equivalent to operator+=().
### QString & QString::append ( const char * str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the result.
Equivalent to operator+=().
### QString & QString::append ( const std::string & str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the result.
Equivalent to operator+=().
### QStringQString::arg ( const QString & a, int fieldWidth = 0 ) const
This function will return a string that replaces the lowest numbered occurrence of %1, %2, ..., %9 with a.
The fieldWidth value specifies the minimum amount of space that a is padded to. A positive value will produce right-aligned text, whereas a negative value will produce left-aligned text.
The following example shows how we could create a 'status' string when processing a list of files:
QString status = QString( "Processing file %1 of %2: %3" )
.arg( i ) // current file's number
.arg( total ) // number of files to process
.arg( fileName ); // current file's name
It is generally fine to use filenames and numbers as we have done in the example above. But note that using arg() to construct natural language sentences does not usually translate well into other languages because sentence structure and word order often differ between languages.
If there is no place marker (%1, %2, etc.), a warning message (qWarning()) is output and the result is undefined.
### QStringQString::arg ( long a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
The fieldWidth value specifies the minimum amount of space that a is padded to. A positive value will produce a right-aligned number, whereas a negative value will produce a left-aligned number.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
QString str;
str = QString( "Decimal 63 is %1 in hexadecimal" )
.arg( 63, 0, 16 );
// str == "Decimal 63 is 3f in hexadecimal"
### QStringQString::arg ( ulong a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( Q_LLONG a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( Q_ULLONG a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( int a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( uint a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( short a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( ushort a, int fieldWidth = 0, int base = 10 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is expressed in base base, which is 10 by default and must be between 2 and 36.
### QStringQString::arg ( double a, int fieldWidth = 0, char fmt = 'g', int prec = -1 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Argument a is formatted according to the fmt format specified, which is 'g' by default and can be any of the following:
Format Meaning
e format as [-]9.9e[+|-]999
E format as [-]9.9E[+|-]999
f format as [-]9.9
g use e or f format, whichever is the most concise
G use E or f format, whichever is the most concise
With 'e', 'E', and 'f', prec is the number of digits after the decimal point. With 'g' and 'G', prec is the maximum number of significant digits (trailing zeroes are omitted).
double d = 12.34;
QString ds = QString( "'E' format, precision 3, gives %1" )
.arg( d, 0, 'E', 3 );
// ds == "1.234E+001"
### QStringQString::arg ( char a, int fieldWidth = 0 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
a is assumed to be in the Latin-1 character set.
### QStringQString::arg ( QChar a, int fieldWidth = 0 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::arg ( const QString & a1, const QString & a2 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is the same as str.arg(a1).arg(a2), except that the strings are replaced in one pass. This can make a difference if a1 contains e.g. %1:
QString str( "%1 %2" );
str.arg( "Hello", "world" ); // returns "Hello world"
str.arg( "Hello" ).arg( "world" ); // returns "Hello world"
str.arg( "(%1)", "Hello" ); // returns "(%1) Hello"
str.arg( "(%1)" ).arg( "Hello" ); // returns "(Hello) %2"
### QStringQString::arg ( const QString & a1, const QString & a2, const QString & a3 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is the same as calling str.arg(a1).arg(a2).arg(a3), except that the strings are replaced in one pass.
### QStringQString::arg ( const QString & a1, const QString & a2, const QString & a3, const QString & a4 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is the same as calling str.arg(a1).arg(a2).arg(a3).arg(a4), except that the strings are replaced in one pass.
### const char * QString::ascii () const
Returns an 8-bit ASCII representation of the string.
If a codec has been set using QTextCodec::codecForCStrings(), it is used to convert Unicode to 8-bit char. Otherwise, this function does the same as latin1().
Example: network/networkprotocol/nntp.cpp.
### QCharQString::at ( uint i ) const
Returns the character at index i, or 0 if i is beyond the length of the string.
const QString string( "abcdefgh" );
QChar ch = string.at( 4 );
// ch == 'e'
If the QString is not const (i.e. const QString) or const& (i.e. const QString &), then the non-const overload of at() will be used instead.
### QCharRefQString::at ( uint i )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
The function returns a reference to the character at index i. The resulting reference can then be assigned to, or used immediately, but it will become invalid once further modifications are made to the original string.
If i is beyond the length of the string then the string is expanded with QChar::null.
### uint QString::capacity () const
Returns the number of characters this string can hold in the allocated memory.
### int QString::compare ( const QString & s1, const QString & s2 ) [static]
Lexically compares s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2.
The comparison is based exclusively on the numeric Unicode values of the characters and is very fast, but is not what a human would expect. Consider sorting user-interface strings with QString::localeAwareCompare().
int a = QString::compare( "def", "abc" ); // a > 0
int b = QString::compare( "abc", "def" ); // b < 0
int c = QString::compare(" abc", "abc" ); // c == 0
### int QString::compare ( const QString & s ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Lexically compares this string with s and returns an integer less than, equal to, or greater than zero if it is less than, equal to, or greater than s.
### void QString::compose ()
Warning: This function is not supported in Qt 3.x. It is provided for experimental and illustrative purposes only. It is mainly of interest to those experimenting with Arabic and other composition-rich texts.
Applies possible ligatures to a QString. Useful when composition-rich text requires rendering with glyph-poor fonts, but it also makes compositions such as QChar(0x0041) ('A') and QChar(0x0308) (Unicode accent diaresis), giving QChar(0x00c4) (German A Umlaut).
### QCharQString::constref ( uint i ) const
Returns the QChar at index i by value.
Equivalent to at(i).
### int QString::contains ( QChar c, bool cs = TRUE ) const
Returns the number of times the character c occurs in the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
QString string( "Trolltech and Qt" );
int n = string.contains( 't', FALSE );
// n == 3
Examples: fileiconview/qfileiconview.cpp and mdi/application.cpp.
### int QString::contains ( char c, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### int QString::contains ( const char * str, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns the number of times the string str occurs in the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
### int QString::contains ( const QString & str, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns the number of times str occurs in the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
This function counts overlapping strings, so in the example below, there are two instances of "ana" in "bananas".
QString str( "bananas" );
int i = str.contains( "ana" ); // i == 2
### int QString::contains ( const QRegExp & rx ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns the number of times the regexp, rx, matches in the string.
This function counts overlapping matches, so in the example below, there are four instances of "ana" or "ama".
QString str = "banana and panama";
QRegExp rxp = QRegExp( "a[nm]a", TRUE, FALSE );
int i = str.contains( rxp ); // i == 4
### QStringQString::copy () const
This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.
In Qt 2.0 and later, all calls to this function are needless. Just remove them.
### const char * QString::data () const
This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.
Returns a pointer to a '\0'-terminated classic C string.
In Qt 1.x, this returned a char* allowing direct manipulation of the string as a sequence of bytes. In Qt 2.x where QString is a Unicode string, char* conversion constructs a temporary string, and hence direct character operations are meaningless.
### bool QString::endsWith ( const QString & s, bool cs = TRUE ) const
Returns TRUE if the string ends with s; otherwise returns FALSE.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
QString str( "Bananas" );
str.endsWith( "anas" ); // returns TRUE
str.endsWith( "pple" ); // returns FALSE
Example: chart/main.cpp.
### QString & QString::fill ( QChar c, int len = -1 )
Fills the string with len characters of value c, and returns a reference to the string.
If len is negative (the default), the current string length is used.
QString str;
str.fill( 'g', 5 ); // string == "ggggg"
### int QString::find ( const QRegExp & rx, int index = 0 ) const
Finds the first match of the regular expression rx, starting from position index. If index is -1, the search starts at the last character; if -2, at the next to last character and so on. (See findRev() for searching backwards.)
Returns the position of the first match of rx or -1 if no match was found.
QString string( "bananas" );
int i = string.find( QRegExp("an"), 0 ); // i == 1
Example: network/mail/smtp.cpp.
### int QString::find ( QChar c, int index = 0, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Finds the first occurrence of the character c, starting at position index. If index is -1, the search starts at the last character; if -2, at the next to last character and so on. (See findRev() for searching backwards.)
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
Returns the position of c or -1 if c could not be found.
### int QString::find ( char c, int index = 0, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Find character c starting from position index.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
### int QString::find ( const QString & str, int index = 0, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Finds the first occurrence of the string str, starting at position index. If index is -1, the search starts at the last character, if it is -2, at the next to last character and so on. (See findRev() for searching backwards.)
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
Returns the position of str or -1 if str could not be found.
### int QString::find ( const char * str, int index = 0 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Equivalent to find(QString(str), index).
### int QString::findRev ( const char * str, int index = -1 ) const
Equivalent to findRev(QString(str), index).
### int QString::findRev ( QChar c, int index = -1, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Finds the first occurrence of the character c, starting at position index and searching backwards. If the index is -1, the search starts at the last character, if it is -2, at the next to last character and so on.
Returns the position of c or -1 if c could not be found.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
QString string( "bananas" );
int i = string.findRev( 'a' ); // i == 5
### int QString::findRev ( char c, int index = -1, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Find character c starting from position index and working backwards.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
### int QString::findRev ( const QString & str, int index = -1, bool cs = TRUE ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Finds the first occurrence of the string str, starting at position index and searching backwards. If the index is -1, the search starts at the last character, if it is -2, at the next to last character and so on.
Returns the position of str or -1 if str could not be found.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
QString string("bananas");
int i = string.findRev( "ana" ); // i == 3
### int QString::findRev ( const QRegExp & rx, int index = -1 ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Finds the first match of the regexp rx, starting at position index and searching backwards. If the index is -1, the search starts at the last character, if it is -2, at the next to last character and so on. (See findRev() for searching backwards.)
Returns the position of the match or -1 if no match was found.
QString string( "bananas" );
int i = string.findRev( QRegExp("an") ); // i == 3
### QStringQString::fromAscii ( const char * ascii, int len = -1 ) [static]
Returns the Unicode string decoded from the first len characters of ascii, ignoring the rest of ascii. If len is -1 then the length of ascii is used. If len is bigger than the length of ascii then it will use the length of ascii.
If a codec has been set using QTextCodec::codecForCStrings(), it is used to convert Unicode to 8-bit char. Otherwise, this function does the same as fromLatin1().
This is the same as the QString(const char*) constructor, but you can make that constructor invisible if you compile with the define QT_NO_CAST_ASCII, in which case you can explicitly create a QString from 8-bit ASCII text using this function.
QString str = QString::fromAscii( "123456789", 5 );
// str == "12345"
### QStringQString::fromLatin1 ( const char * chars, int len = -1 ) [static]
Returns the Unicode string decoded from the first len characters of chars, ignoring the rest of chars. If len is -1 then the length of chars is used. If len is bigger than the length of chars then it will use the length of chars.
Examples: listbox/listbox.cpp and network/mail/smtp.cpp.
### QStringQString::fromLocal8Bit ( const char * local8Bit, int len = -1 ) [static]
Returns the Unicode string decoded from the first len characters of local8Bit, ignoring the rest of local8Bit. If len is -1 then the length of local8Bit is used. If len is bigger than the length of local8Bit then it will use the length of local8Bit.
QString str = QString::fromLocal8Bit( "123456789", 5 );
// str == "12345"
local8Bit is assumed to be encoded in a locale-specific format.
See QTextCodec for more diverse coding/decoding of Unicode strings.
### QStringQString::fromUcs2 ( const unsigned short * str ) [static]
Constructs a string that is a deep copy of str, interpreted as a UCS2 encoded, zero terminated, Unicode string.
If str is 0, then a null string is created.
### QStringQString::fromUtf8 ( const char * utf8, int len = -1 ) [static]
Returns the Unicode string decoded from the first len characters of utf8, ignoring the rest of utf8. If len is -1 then the length of utf8 is used. If len is bigger than the length of utf8 then it will use the length of utf8.
QString str = QString::fromUtf8( "123456789", 5 );
// str == "12345"
See QTextCodec for more diverse coding/decoding of Unicode strings.
Example: fonts/simple-qfont-demo/viewer.cpp.
### QString & QString::insert ( uint index, const QString & s )
Inserts s into the string at position index.
If index is beyond the end of the string, the string is extended with spaces to length index and s is then appended and returns a reference to the string.
QString string( "I like fish" );
str = string.insert( 2, "don't " );
// str == "I don't like fish"
Examples: themes/themes.cpp and xform/xform.cpp.
### QString & QString::insert ( uint index, const QByteArray & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts s into the string at position index and returns a reference to the string.
### QString & QString::insert ( uint index, const char * s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts s into the string at position index and returns a reference to the string.
### QString & QString::insert ( uint index, const QChar * s, uint len )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts the first len characters in s into the string at position index and returns a reference to the string.
### QString & QString::insert ( uint index, QChar c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Insert c into the string at position index and returns a reference to the string.
If index is beyond the end of the string, the string is extended with spaces (ASCII 32) to length index and c is then appended.
### QString & QString::insert ( uint index, char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Insert character c at position index.
### bool QString::isEmpty () const
Returns TRUE if the string is empty, i.e. if length() == 0; otherwise returns FALSE. Null strings are also empty.
QString a( "" );
a.isEmpty(); // TRUE
a.isNull(); // FALSE
QString b;
b.isEmpty(); // TRUE
b.isNull(); // TRUE
### bool QString::isNull () const
Returns TRUE if the string is null; otherwise returns FALSE. A null string is always empty.
QString a; // a.unicode() == 0, a.length() == 0
a.isNull(); // TRUE, because a.unicode() == 0
a.isEmpty(); // TRUE, because a.length() == 0
Examples: i18n/main.cpp, network/ftpclient/ftpmainwindow.ui.h, and qdir/qdir.cpp.
### const char * QString::latin1 () const
Returns a Latin-1 representation of the string. The returned value is undefined if the string contains non-Latin-1 characters. If you want to convert strings into formats other than Unicode, see the QTextCodec classes.
This function is mainly useful for boot-strapping legacy code to use Unicode.
The result remains valid so long as one unmodified copy of the source string exists.
### QStringQString::left ( uint len ) const
Returns a substring that contains the len leftmost characters of the string.
The whole string is returned if len exceeds the length of the string.
QString s = "Pineapple";
QString t = s.left( 4 ); // t == "Pine"
Example: themes/themes.cpp.
### QStringQString::leftJustify ( uint width, QChar fill = ' ', bool truncate = FALSE ) const
Returns a string of length width that contains this string padded by the fill character.
If truncate is FALSE and the length of the string is more than width, then the returned string is a copy of the string.
If truncate is TRUE and the length of the string is more than width, then any characters in a copy of the string after length width are removed, and the copy is returned.
QString s( "apple" );
QString t = s.leftJustify( 8, '.' ); // t == "apple..."
### uint QString::length () const
Returns the length of the string.
Null strings and empty strings have zero length.
### QCStringQString::local8Bit () const
Returns the string encoded in a locale-specific format. On X11, this is the QTextCodec::codecForLocale(). On Windows, it is a system-defined encoding. On Mac OS X, this always uses UTF-8 as the encoding.
See QTextCodec for more diverse coding/decoding of Unicode strings.
### int QString::localeAwareCompare ( const QString & s1, const QString & s2 ) [static]
Compares s1 with s2 and returns an integer less than, equal to, or greater than zero if s1 is less than, equal to, or greater than s2.
The comparison is performed in a locale- and also platform-dependent manner. Use this function to present sorted lists of strings to the user.
### int QString::localeAwareCompare ( const QString & s ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Compares this string with s.
### QStringQString::lower () const
Returns a lowercase copy of the string.
QString string( "TROlltECH" );
str = string.lower(); // str == "trolltech"
Example: scribble/scribble.cpp.
### QStringQString::mid ( uint index, uint len = 0xffffffff ) const
Returns a string that contains the len characters of this string, starting at position index.
Returns a null string if the string is empty or index is out of range. Returns the whole string from index if index + len exceeds the length of the string.
QString s( "Five pineapples" );
QString t = s.mid( 5, 4 ); // t == "pine"
Examples: network/mail/smtp.cpp, qmag/qmag.cpp, and themes/themes.cpp.
### QStringQString::number ( long n, int base = 10 ) [static]
A convenience function that returns a string equivalent of the number n to base base, which is 10 by default and must be between 2 and 36.
long a = 63;
QString str = QString::number( a, 16 ); // str == "3f"
QString str = QString::number( a, 16 ).upper(); // str == "3F"
### QStringQString::number ( ulong n, int base = 10 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::number ( Q_LLONG n, int base = 10 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::number ( Q_ULLONG n, int base = 10 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::number ( int n, int base = 10 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::number ( uint n, int base = 10 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
A convenience factory function that returns a string representation of the number n to the base base, which is 10 by default and must be between 2 and 36.
### QStringQString::number ( double n, char f = 'g', int prec = 6 ) [static]
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Argument n is formatted according to the f format specified, which is g by default, and can be any of the following:
Format Meaning
e format as [-]9.9e[+|-]999
E format as [-]9.9E[+|-]999
f format as [-]9.9
g use e or f format, whichever is the most concise
G use E or f format, whichever is the most concise
With 'e', 'E', and 'f', prec is the number of digits after the decimal point. With 'g' and 'G', prec is the maximum number of significant digits (trailing zeroes are omitted).
double d = 12.34;
QString ds = QString( "'E' format, precision 3, gives %1" )
.arg( d, 0, 'E', 3 );
// ds == "1.234E+001"
### QString::operator const char * () const
Returns latin1(). Be sure to see the warnings documented in the latin1() function. Note that for new code which you wish to be strictly Unicode-clean, you can define the macro QT_NO_ASCII_CAST when compiling your code to hide this function so that automatic casts are not done. This has the added advantage that you catch the programming error described in operator!().
Returns ascii().
### bool QString::operator! () const
Returns TRUE if this is a null string; otherwise returns FALSE.
QString name = getName();
if ( !name )
name = "Rodney";
Note that if you say
QString name = getName();
if ( name )
doSomethingWith(name);
It will call "operator const char*()", which is inefficent; you may wish to define the macro QT_NO_ASCII_CAST when writing code which you wish to remain Unicode-clean.
When you want the above semantics, use:
QString name = getName();
if ( !name.isNull() )
doSomethingWith(name);
### QString & QString::operator+= ( const QString & str )
Appends str to the string and returns a reference to the string.
### QString & QString::operator+= ( const QByteArray & str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the string.
### QString & QString::operator+= ( const char * str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the string.
### QString & QString::operator+= ( const std::string & str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends str to the string and returns a reference to the string.
### QString & QString::operator+= ( QChar c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends c to the string and returns a reference to the string.
### QString & QString::operator+= ( char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Appends c to the string and returns a reference to the string.
### QString & QString::operator= ( QChar c )
Sets the string to contain just the single character c.
### QString & QString::operator= ( const QString & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Assigns a shallow copy of s to this string and returns a reference to this string. This is very fast because the string isn't actually copied.
### QString & QString::operator= ( const char * str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Assigns a deep copy of str, interpreted as a classic C string to this string and returns a reference to this string.
If str is 0, then a null string is created.
### QString & QString::operator= ( const std::string & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Makes a deep copy of s and returns a reference to the deep copy.
### QString & QString::operator= ( const QCString & cstr )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Assigns a deep copy of cstr, interpreted as a classic C string, to this string. Returns a reference to this string.
### QString & QString::operator= ( char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to contain just the single character c.
### QCharQString::operator[] ( int i ) const
Returns the character at index i, or QChar::null if i is beyond the length of the string.
If the QString is not const (i.e., const QString) or const& (i.e., const QString&), then the non-const overload of operator[] will be used instead.
### QCharRefQString::operator[] ( int i )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
The function returns a reference to the character at index i. The resulting reference can then be assigned to, or used immediately, but it will become invalid once further modifications are made to the original string.
If i is beyond the length of the string then the string is expanded with QChar::nulls, so that the QCharRef references a valid (null) character in the string.
The QCharRef internal class can be used much like a constant QChar, but if you assign to it, you change the original string (which will detach itself because of QString's copy-on-write semantics). You will get compilation errors if you try to use the result as anything but a QChar.
### QString & QString::prepend ( const QString & s )
Inserts s at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, s).
QString string = "42";
string.prepend( "The answer is " );
// string == "The answer is 42"
### QString & QString::prepend ( char ch )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts ch at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, ch).
### QString & QString::prepend ( QChar ch )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts ch at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, ch).
### QString & QString::prepend ( const QByteArray & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts s at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, s).
### QString & QString::prepend ( const char * s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts s at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, s).
### QString & QString::prepend ( const std::string & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Inserts s at the beginning of the string and returns a reference to the string.
Equivalent to insert(0, s).
### QChar & QString::ref ( uint i )
Returns the QChar at index i by reference, expanding the string with QChar::null if necessary. The resulting reference can be assigned to, or otherwise used immediately, but becomes invalid once furher modifications are made to the string.
QString string("ABCDEF");
QChar ch = string.ref( 3 ); // ch == 'D'
### QString & QString::remove ( uint index, uint len )
Removes len characters from the string starting at position index, and returns a reference to the string.
If index is beyond the length of the string, nothing happens. If index is within the string, but index + len is beyond the end of the string, the string is truncated at position index.
QString string( "Montreal" );
string.remove( 1, 4 ); // string == "Meal"
### QString & QString::remove ( const QString & str, bool cs = TRUE )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Removes every occurrence of str in the string. Returns a reference to the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
This is the same as replace(str, "", cs).
### QString & QString::remove ( QChar c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Removes every occurrence of the character c in the string. Returns a reference to the string.
This is the same as replace(c, "").
### QString & QString::remove ( char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Removes every occurrence of the character c in the string. Returns a reference to the string.
This is the same as replace(c, "").
### QString & QString::remove ( const char * str )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Removes every occurrence of str in the string. Returns a reference to the string.
### QString & QString::remove ( const QRegExp & rx )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Removes every occurrence of the regular expression rx in the string. Returns a reference to the string.
This is the same as replace(rx, "").
### QString & QString::replace ( uint index, uint len, const QString & s )
Replaces len characters from the string with s, starting at position index, and returns a reference to the string.
If index is beyond the length of the string, nothing is deleted and s is appended at the end of the string. If index is valid, but index + len is beyond the end of the string, the string is truncated at position index, then s is appended at the end.
QString string( "Say yes!" );
string = string.replace( 4, 3, "NO" );
// string == "Say NO!"
### QString & QString::replace ( uint index, uint len, const QChar * s, uint slen )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces len characters with slen characters of QChar data from s, starting at position index, and returns a reference to the string.
### QString & QString::replace ( uint index, uint len, QChar c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is the same as replace(index, len, QString(c)).
### QString & QString::replace ( uint index, uint len, char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This is the same as replace(index, len, QChar(c)).
### QString & QString::replace ( QChar c, const QString & after, bool cs = TRUE )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces every occurrence of the character c in the string with after. Returns a reference to the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
Example:
QString s = "a,b,c";
s.replace( QChar(','), " or " );
// s == "a or b or c"
### QString & QString::replace ( char c, const QString & after, bool cs = TRUE )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces every occurrence of the character c in the string with after. Returns a reference to the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
### QString & QString::replace ( const QString & before, const QString & after, bool cs = TRUE )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces every occurrence of the string before in the string with the string after. Returns a reference to the string.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
Example:
QString s = "Greek is Greek";
s.replace( "Greek", "English" );
// s == "English is English"
### QString & QString::replace ( const QRegExp & rx, const QString & after )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces every occurrence of the regexp rx in the string with after. Returns a reference to the string. For example:
QString s = "banana";
s.replace( QRegExp("an"), "" );
// s == "ba"
For regexps containing capturing parentheses, occurrences of \1, \2, ..., in after are replaced with rx.cap(1), cap(2), ...
QString t = "A <i>bon mot</i>.";
t.replace( QRegExp("<i>([^<]*)</i>"), "\\emph{\\1}" );
// t == "A \\emph{bon mot}."
### QString & QString::replace ( QChar c1, QChar c2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Replaces every occurrence of c1 with the char c2. Returns a reference to the string.
### void QString::reserve ( uint minCapacity )
Ensures that at least minCapacity characters are allocated to the string.
This function is useful for code that needs to build up a long string and wants to avoid repeated reallocation. In this example, we want to add to the string until some condition is true, and we're fairly sure that size is big enough:
QString result;
int len = 0;
result.reserve(maxLen);
while (...) {
result[len++] = ... // fill part of the space
}
result.squeeze();
If maxLen is an underestimate, the worst that will happen is that the loop will slow down.
If it is not possible to allocate enough memory, the string remains unchanged.
### QStringQString::right ( uint len ) const
Returns a string that contains the len rightmost characters of the string.
If len is greater than the length of the string then the whole string is returned.
QString string( "Pineapple" );
QString t = string.right( 5 ); // t == "apple"
Example: fileiconview/qfileiconview.cpp.
### QStringQString::rightJustify ( uint width, QChar fill = ' ', bool truncate = FALSE ) const
Returns a string of length width that contains the fill character followed by the string.
If truncate is FALSE and the length of the string is more than width, then the returned string is a copy of the string.
If truncate is TRUE and the length of the string is more than width, then the resulting string is truncated at position width.
QString string( "apple" );
QString t = string.rightJustify( 8, '.' ); // t == "...apple"
### QStringQString::section ( QChar sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
This function returns a section of the string.
This string is treated as a sequence of fields separated by the character, sep. The returned string consists of the fields from position start to position end inclusive. If end is not specified, all fields from position start to the end of the string are included. Fields are numbered 0, 1, 2, etc., counting from the left, and -1, -2, etc., counting from right to left.
The flags argument can be used to affect some aspects of the function's behaviour, e.g. whether to be case sensitive, whether to skip empty fields and how to deal with leading and trailing separators; see SectionFlags.
QString csv( "forename,middlename,surname,phone" );
QString s = csv.section( ',', 2, 2 ); // s == "surname"
QString path( "/usr/local/bin/myapp" ); // First field is empty
QString s = path.section( '/', 3, 4 ); // s == "bin/myapp"
QString s = path.section( '/', 3, 3, SectionSkipEmpty ); // s == "myapp"
If start or end is negative, we count fields from the right of the string, the right-most field being -1, the one from right-most field being -2, and so on.
QString csv( "forename,middlename,surname,phone" );
QString s = csv.section( ',', -3, -2 ); // s == "middlename,surname"
QString path( "/usr/local/bin/myapp" ); // First field is empty
QString s = path.section( '/', -1 ); // s == "myapp"
### QStringQString::section ( char sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::section ( const char * sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QStringQString::section ( const QString & sep, int start, int end = 0xffffffff, int flags = SectionDefault ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This function returns a section of the string.
This string is treated as a sequence of fields separated by the string, sep. The returned string consists of the fields from position start to position end inclusive. If end is not specified, all fields from position start to the end of the string are included. Fields are numbered 0, 1, 2, etc., counting from the left, and -1, -2, etc., counting from right to left.
The flags argument can be used to affect some aspects of the function's behaviour, e.g. whether to be case sensitive, whether to skip empty fields and how to deal with leading and trailing separators; see SectionFlags.
QString data( "forename**middlename**surname**phone" );
QString s = data.section( "**", 2, 2 ); // s == "surname"
If start or end is negative, we count fields from the right of the string, the right-most field being -1, the one from right-most field being -2, and so on.
QString data( "forename**middlename**surname**phone" );
QString s = data.section( "**", -3, -2 ); // s == "middlename**surname"
### QStringQString::section ( const QRegExp & reg, int start, int end = 0xffffffff, int flags = SectionDefault ) const
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
This function returns a section of the string.
This string is treated as a sequence of fields separated by the regular expression, reg. The returned string consists of the fields from position start to position end inclusive. If end is not specified, all fields from position start to the end of the string are included. Fields are numbered 0, 1, 2, etc., counting from the left, and -1, -2, etc., counting from right to left.
The flags argument can be used to affect some aspects of the function's behaviour, e.g. whether to be case sensitive, whether to skip empty fields and how to deal with leading and trailing separators; see SectionFlags.
QString line( "forename\tmiddlename surname \t \t phone" );
QRegExp sep( "\s+" );
QString s = line.section( sep, 2, 2 ); // s == "surname"
If start or end is negative, we count fields from the right of the string, the right-most field being -1, the one from right-most field being -2, and so on.
QString line( "forename\tmiddlename surname \t \t phone" );
QRegExp sep( "\\s+" );
QString s = line.section( sep, -3, -2 ); // s == "middlename surname"
Warning: Using this QRegExp version is much more expensive than the overloaded string and character versions.
### QString & QString::setAscii ( const char * str, int len = -1 )
Sets this string to str, interpreted as a classic 8-bit ASCII C string. If len is -1 (the default), then it is set to strlen(str).
If str is 0 a null string is created. If str is "", an empty string is created.
### void QString::setExpand ( uint index, QChar c )
This function is obsolete. It is provided to keep old source working. We strongly advise against using it in new code.
Sets the character at position index to c and expands the string if necessary, filling with spaces.
This method is redundant in Qt 3.x, because operator[] will expand the string as necessary.
### QString & QString::setLatin1 ( const char * str, int len = -1 )
Sets this string to str, interpreted as a classic Latin-1 C string. If len is -1 (the default), then it is set to strlen(str).
If str is 0 a null string is created. If str is "", an empty string is created.
### void QString::setLength ( uint newLen )
Ensures that at least newLen characters are allocated to the string, and sets the length of the string to newLen. Any new space allocated contains arbitrary data.
### QString & QString::setNum ( Q_LLONG n, int base = 10 )
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
QString string;
string = string.setNum( 1234 ); // string == "1234"
### QString & QString::setNum ( short n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
### QString & QString::setNum ( ushort n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
### QString & QString::setNum ( int n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
### QString & QString::setNum ( uint n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
### QString & QString::setNum ( long n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QString & QString::setNum ( ulong n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
### QString & QString::setNum ( Q_ULLONG n, int base = 10 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n in base base and returns a reference to the string.
The base is 10 by default and must be between 2 and 36.
### QString & QString::setNum ( float n, char f = 'g', int prec = 6 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n, formatted in format f with precision prec, and returns a reference to the string.
The format f can be 'f', 'F', 'e', 'E', 'g' or 'G'. See arg() for an explanation of the formats.
### QString & QString::setNum ( double n, char f = 'g', int prec = 6 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Sets the string to the printed value of n, formatted in format f with precision prec, and returns a reference to the string.
The format f can be 'f', 'F', 'e', 'E', 'g' or 'G'. See arg() for an explanation of the formats.
### QString & QString::setUnicode ( const QChar * unicode, uint len )
Resizes the string to len characters and copies unicode into the string. If unicode is 0, nothing is copied, but the string is still resized to len. If len is zero, then the string becomes a null string.
### QString & QString::setUnicodeCodes ( const ushort * unicode_as_ushorts, uint len )
Resizes the string to len characters and copies unicode_as_ushorts into the string (on some X11 client platforms this will involve a byte-swapping pass).
If unicode_as_ushorts is 0, nothing is copied, but the string is still resized to len. If len is zero, the string becomes a null string.
### QStringQString::simplifyWhiteSpace () const
Returns a string that has whitespace removed from the start and the end, and which has each sequence of internal whitespace replaced with a single space.
Whitespace means any character for which QChar::isSpace() returns TRUE. This includes Unicode characters with decimal values 9 (TAB), 10 (LF), 11 (VT), 12 (FF), 13 (CR), and 32 (Space).
QString string = " lots\t of\nwhite space ";
QString t = string.simplifyWhiteSpace();
// t == "lots of white space"
### QString & QString::sprintf ( const char * cformat, ... )
Safely builds a formatted string from the format string cformat and an arbitrary list of arguments. The format string supports all the escape sequences of printf() in the standard C library.
The %s escape sequence expects a utf8() encoded string. The format string cformat is expected to be in latin1. If you need a Unicode format string, use arg() instead. For typesafe string building, with full Unicode support, you can use QTextOStream like this:
QString str;
QString s = ...;
int x = ...;
QTextOStream( &str ) << s << " : " << x;
For translations, especially if the strings contains more than one escape sequence, you should consider using the arg() function instead. This allows the order of the replacements to be controlled by the translator, and has Unicode support.
### void QString::squeeze ()
Squeezes the string's capacity to the current content.
### bool QString::startsWith ( const QString & s, bool cs = TRUE ) const
Returns TRUE if the string starts with s; otherwise returns FALSE.
If cs is TRUE (the default), the search is case sensitive; otherwise the search is case insensitive.
QString str( "Bananas" );
str.startsWith( "Ban" ); // returns TRUE
str.startsWith( "Car" ); // returns FALSE
### QStringQString::stripWhiteSpace () const
Returns a string that has whitespace removed from the start and the end.
Whitespace means any character for which QChar::isSpace() returns TRUE. This includes Unicode characters with decimal values 9 (TAB), 10 (LF), 11 (VT), 12 (FF), 13 (CR) and 32 (Space), and may also include other Unicode characters.
QString string = " white space ";
QString s = string.stripWhiteSpace(); // s == "white space"
### double QString::toDouble ( bool * ok = 0 ) const
Returns the string converted to a double value.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
QString string( "1234.56" );
double a = string.toDouble(); // a == 1234.56
### float QString::toFloat ( bool * ok = 0 ) const
Returns the string converted to a float value.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### int QString::toInt ( bool * ok = 0, int base = 10 ) const
Returns the string converted to an int value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
QString str( "FF" );
bool ok;
int hex = str.toInt( &ok, 16 ); // hex == 255, ok == TRUE
int dec = str.toInt( &ok, 10 ); // dec == 0, ok == FALSE
### long QString::toLong ( bool * ok = 0, int base = 10 ) const
Returns the string converted to a long value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### Q_LLONG QString::toLongLong ( bool * ok = 0, int base = 10 ) const
Returns the string converted to a long long value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### short QString::toShort ( bool * ok = 0, int base = 10 ) const
Returns the string converted to a short value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### uint QString::toUInt ( bool * ok = 0, int base = 10 ) const
Returns the string converted to an unsigned int value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### ulong QString::toULong ( bool * ok = 0, int base = 10 ) const
Returns the string converted to an unsigned long value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### Q_ULLONG QString::toULongLong ( bool * ok = 0, int base = 10 ) const
Returns the string converted to an unsigned long long value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### ushort QString::toUShort ( bool * ok = 0, int base = 10 ) const
Returns the string converted to an unsigned short value to the base base, which is 10 by default and must be between 2 and 36.
If ok is not 0: if a conversion error occurs, *ok is set to FALSE; otherwise *ok is set to TRUE.
### void QString::truncate ( uint newLen )
If newLen is less than the length of the string, then the string is truncated at position newLen. Otherwise nothing happens.
QString s = "truncate me";
s.truncate( 5 ); // s == "trunc"
Example: network/mail/smtp.cpp.
### const unsigned short * QString::ucs2 () const
Returns the QString as a zero terminated array of unsigned shorts if the string is not null; otherwise returns zero.
The result remains valid so long as one unmodified copy of the source string exists.
### const QChar * QString::unicode () const
Returns the Unicode representation of the string. The result remains valid until the string is modified.
### QStringQString::upper () const
Returns an uppercase copy of the string.
QString string( "TeXt" );
str = string.upper(); // t == "TEXT"
Examples: scribble/scribble.cpp and sql/overview/custom1/main.cpp.
### QCStringQString::utf8 () const
Returns the string encoded in UTF-8 format.
See QTextCodec for more diverse coding/decoding of Unicode strings.
## Related Functions
### bool operator!= ( const QString & s1, const QString & s2 )
Returns TRUE if s1 is not equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) != 0.
### bool operator!= ( const QString & s1, const char * s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is not equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) != 0.
### bool operator!= ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is not equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) != 0.
### const QStringoperator+ ( const QString & s1, const QString & s2 )
Returns a string which is the result of concatenating the string s1 and the string s2.
Equivalent to s1.append(s2).
### const QStringoperator+ ( const QString & s1, const char * s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns a string which is the result of concatenating the string s1 and character s2.
Equivalent to s1.append(s2).
### const QStringoperator+ ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns a string which is the result of concatenating the character s1 and string s2.
### const QStringoperator+ ( const QString & s, char c )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns a string which is the result of concatenating the string s and character c.
Equivalent to s.append(c).
### const QStringoperator+ ( char c, const QString & s )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns a string which is the result of concatenating the character c and string s.
Equivalent to s.prepend(c).
### bool operator< ( const QString & s1, const char * s2 )
Returns TRUE if s1 is lexically less than s2; otherwise returns FALSE. The comparison is case sensitive.
Equivalent to compare(s1, s2) < 0.
### bool operator< ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is lexically less than s2; otherwise returns FALSE. The comparison is case sensitive.
Equivalent to compare(s1, s2) < 0.
### QDataStream & operator<< ( QDataStream & s, const QString & str )
Writes the string str to the stream s.
### bool operator<= ( const QString & s1, const char * s2 )
Returns TRUE if s1 is lexically less than or equal to s2; otherwise returns FALSE. The comparison is case sensitive. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1,s2) <= 0.
### bool operator<= ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is lexically less than or equal to s2; otherwise returns FALSE. The comparison is case sensitive. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) <= 0.
### bool operator== ( const QString & s1, const QString & s2 )
Returns TRUE if s1 is equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) != 0.
### bool operator== ( const QString & s1, const char * s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) == 0.
### bool operator== ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is equal to s2; otherwise returns FALSE. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) == 0.
### bool operator> ( const QString & s1, const char * s2 )
Returns TRUE if s1 is lexically greater than s2; otherwise returns FALSE. The comparison is case sensitive.
Equivalent to compare(s1, s2) > 0.
### bool operator> ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is lexically greater than s2; otherwise returns FALSE. The comparison is case sensitive.
Equivalent to compare(s1, s2) > 0.
### bool operator>= ( const QString & s1, const char * s2 )
Returns TRUE if s1 is lexically greater than or equal to s2; otherwise returns FALSE. The comparison is case sensitive. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) >= 0.
### bool operator>= ( const char * s1, const QString & s2 )
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
Returns TRUE if s1 is lexically greater than or equal to s2; otherwise returns FALSE. The comparison is case sensitive. Note that a null string is not equal to a not-null empty string.
Equivalent to compare(s1, s2) >= 0.
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https://www.onemathematicalcat.org/Math/Precalculus_obj/writeFctComp.htm
|
# WRITING A FUNCTION AS A COMPOSITION
• PRACTICE (online exercises and printable worksheets)
When you're given a multi-step task to perform, you may want to break it into pieces,
and assign different pieces to different people.
When you're given a function that does several things,
you may want to break it into ‘smaller’ functions that accomplish the same job!
## EXAMPLE (breaking a composite function into pieces)
Consider the function $\,h(x) = 5(x-4)^3 - 7\,$.
This function $\,h\,$ does the following:
1. subtracts $\,4\,$
2. cubes the result
3. multiplies by $\,5\,$
4. subtracts $\,7\,$
Break these four tasks into two pieces, as shown in the mapping diagram below:
• assign the first two tasks (subtract $\,4\,$, then cube) to $\,f\$: $f(x) = (x-4)^3$
• assign the last two tasks (multiply by $\,5\,$, then subtract $\,7\,$) to $\,g\$: $g(x) = 5x - 7$
With these assignments, the composite function $\,g\circ f\$ (where $\,f\,$ acts first, followed by $\,g\,$) accomplishes the same thing as $\,h\,$: $$(g\circ f\,)(x) = g(f(x)) = g\bigl((x-4)^3\bigr) = 5(x-4)^3 - 7 = h(x)$$
## You can break a task into pieces in different ways!
Of course, you can delegate the responsibilities in different ways:
• $f\,$ takes the first step (subtract $4$): $f(x) = x-4$
$g\,$ takes the other three steps (cube, multiply by $5$, subtract $7$): $g(x) = 5x^3 - 7$
• $f\,$ takes the first three steps (subtract $4$, cube, multiply by $5$): $f(x) = 5(x-4)^3$
$g\,$ takes the last (subtract $7$): $g(x) = x - 7$
In both cases, be sure to check that $\,(g\circ f\,)(x) = h(x)\,$.
## You can use more than two helpers!
Or, you can use more ‘helper’ functions.
For example:
• let $\ a\$ subtract $4$: $a(x) = x-4$
• let $\ b\$ cube: $b(x) = x^3$
• let $\ c\$ multiply by $5$ and subtract $7$: $c(x) = 5x - 7$
Then,
\displaystyle \begin{align} (c\circ b\circ a\,)(x) &= c(b(a(x)))\cr &= c(b(x-4))\cr &= c((x-4)^3)\cr &= 5(x-4)^3 - 7\cr &= h(x) \end{align}
The exercises in this lesson give you practice with this process of writing a function as a composition.
Master the ideas from this section
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https://www.gamedev.net/forums/topic/148569-extern-struct/
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• ### Popular Now
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#### Archived
This topic is now archived and is closed to further replies.
# extern Struct
This topic is 5471 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.
## Recommended Posts
I have a struct:
struct Window_s {
...
} Window;
created in one cpp file, and I want to use it in other file h/cpp, but if I do extern Window_s Window; I get: error C2146: syntax error : missing '';'' before identifier ''Window''. How to declare extern a struct?
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put the definition of your structure in a header file. then all you need to do is #include that header file in any cpp files that use that structure.
-Arek the Absolute
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You''d better declare your struct in the header file itself. #include that in your other cpp files.
Jappie
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doing that I get a linker error
fatal error LNK1169: one or more multiply defined symbols found
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Note that the definition of the struct (that is, the type, not the particular instance) must be known in each unit where it is known. Note also that the particular instance must be defined only once. Hence, in the header file, define the struct itself and declare the extern instance; define the instance in one source file.
window_s.h
struct Window_s { // ...};extern struct Window_s Window;
window_s.c
#include "window_s.h"struct Window_s Window;
... Now every other source file that #includes window_s.h will also include an extern reference to Window, which is declared exactly once.
This is really no different from declaring, say, an extern int -- it''s just that since the type is user defined, its definition must be included in every compilation unit that uses it.
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sorry for be too heavy, but I have made what miserable tells, and I get linker error unresolved external symbol ''struct Window_s Window''
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quote:
Original post by Anonymous Poster
sorry for be too heavy, but I have made what miserable tells, and I get linker error unresolved external symbol ''struct Window_s Window''
... That''s odd. Are you sure you linked the source file with the actual global variable declaration (window_s.c)? (In IDE''s such as VC++, for those who don''t already know this, this would probably just mean to include the file in the project.)
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http://mathhelpforum.com/algebra/16553-inequality.html
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1. ## inequality
(x-2)*(x+5) < 0
do you just make the < an = and solve there?
I tried expanding doing:
x^2 + 3x - 10
I know (x + 2)(x + 1) = x^2 + 3x + 2 which is similar, so then
(x + 2)(x + 1) - 8 < 0 .. but that doesn't really help me
hmm
2. Originally Posted by flash101
(x-2)*(x+5) < 0
do you just make the < an = and solve there?
I tried expanding doing:
x^2 + 3x - 10
I know (x + 2)(x + 1) = x^2 + 3x + 2 which is similar, so then
(x + 2)(x + 1) - 8 < 0 .. but that doesn't really help me
hmm
you treat the < as an equal sign, then test your results at the end
(x - 2)(x + 5) < 0
=> x - 2 < 0 or x + 5 < 0
=> x < 2 or x < -5
so now we basically think of, or draw a number line, placing the numbers -5 and 2 in there relative positions, and test what regions the original equation holds true for
3. Hello, flash!
$\displaystyle (x-2)(x+5) \:< \:0$
Leave it in factored form . . .
We have: .$\displaystyle (x - 2)(x + 5) \:<\:0$
It says: the product of two numbers is negative.
So one factor must be positive and the other must be negative.
. . There are two possible cases.
[1] .$\displaystyle (x - 2)$ is positive and $\displaystyle (x + 5)$ is negative.
So we have: .$\displaystyle \begin{array}{ccc}x - 2 \:>\:0 & \Rightarrow & x \:> \:2 \\ x+5 \:<\:0 & \Rightarrow & x \:<\:\text{-}5\end{array}$
Hence, $\displaystyle x$ is a number which greater than 2 and less than -5.
. . This is clearly impossible.
[2] .$\displaystyle (x-2)$ is negative and $\displaystyle (x+5)$ is positive.
So we have: .$\displaystyle \begin{array}{ccc}x - 2 \:<\:0 & \Rightarrow & x \:<\:2 \\ x + 5 \:>\:0 & \Rightarrow & x \:>\:\text{-}5\end{array}$
Hence, $\displaystyle x$ is a number which is less than 2 and greater than -5.
This is possible for $\displaystyle x$ between -5 and +2: .$\displaystyle \boxed{-5 \:<\:x\:<\:2}$
4. Flash, remember when you multiply with a negative number, the $\displaystyle >$ will become a $\displaystyle <$ and vice versa.
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http://peeterjoot.com/tag/cylindrical-coordinates/
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## Motivation
In a discord thread on the bivector group (a geometric algebra group chat), MoneyKills posts about trouble he has calculating the correct expression for the angular momentum bivector or it’s dual.
This blog post is a more long winded answer than my bivector response and includes this calculation using both cylindrical and spherical coordinates.
## Cylindrical coordinates.
The position vector for any point on a plane can be expressed as
\label{eqn:amomentum:20}
\Br = r \rcap,
where $$\rcap = \rcap(\phi)$$ encodes all the angular dependence of the position vector, and $$r$$ is the length along that direction to our point, as illustrated in fig. 1.
fig. 1. Cylindrical coordinates position vector.
The radial unit vector has a compact GA representation
\label{eqn:amomentum:40}
\rcap = \Be_1 e^{i\phi},
where $$i = \Be_1 \Be_2$$.
The velocity (or momentum) will have both $$\rcap$$ and $$\phicap$$ dependence. By chain rule, that velocity is
\label{eqn:amomentum:60}
\Bv = \dot{r} \rcap + r \dot{\rcap},
where
\label{eqn:amomentum:80}
\begin{aligned}
\dot{\rcap}
&= \Be_1 i e^{i\phi} \dot{\phi} \\
&= \Be_2 e^{i\phi} \dot{\phi} \\
&= \phicap \dot{\phi}.
\end{aligned}
It is left to the reader to show that the vector designated $$\phicap$$, is a unit vector and perpendicular to $$\rcap$$ (Hint: compute the grade-0 selection of the product of the two to show that they are perpendicular.)
We can now compute the momentum, which is
\label{eqn:amomentum:100}
\Bp = m \Bv = m \lr{ \dot{r} \rcap + r \dot{\phi} \phicap },
and the angular momentum bivector
\label{eqn:amomentum:120}
\begin{aligned}
L
&= \Br \wedge \Bp \\
&= m \lr{ r \rcap } \wedge \lr{ \dot{r} \rcap + r \dot{\phi} \phicap } \\
&= m r^2 \dot{\phi} \rcap \phicap.
\end{aligned}
This has the $$m r^2 \dot{\phi}$$ magnitude that the OP was seeking.
## Spherical coordinates.
In spherical coordinates, our position vector is
\label{eqn:amomentum:140}
\Br = r \lr{ \Be_1 \sin\theta \cos\phi + \Be_2 \sin\theta \sin\phi + \Be_3 \cos\theta },
as sketched in fig. 2.
fig. 2. Spherical coordinates.
We can factor this into a more compact representation
\label{eqn:amomentum:160}
\begin{aligned}
\Br
&= r \lr{ \sin\theta \Be_1 (\cos\phi + \Be_{12} \sin\phi ) + \Be_3 \cos\theta } \\
&= r \lr{ \sin\theta \Be_1 e^{\Be_{12} \phi } + \Be_3 \cos\theta } \\
&= r \Be_3 \lr{ \cos\theta + \sin\theta \Be_3 \Be_1 e^{\Be_{12} \phi } }.
\end{aligned}
It is useful to name two of the bivector terms above, first, we write $$i$$ for the azimuthal plane bivector sketched in fig. 3.
Spherical coordinates, azimuthal plane.
\label{eqn:amomentum:180}
i = \Be_{12},
and introduce a bivector $$j$$ that encodes the $$\Be_3, \rcap$$ plane as sketched in fig. 4.
Spherical coordinates, “j-plane”.
\label{eqn:amomentum:200}
j = \Be_{31} e^{i \phi}.
Having done so, we now have a compact representation for our position vector
\label{eqn:amomentum:220}
\begin{aligned}
\Br
&= r \Be_3 \lr{ \cos\theta + j \sin\theta } \\
&= r \Be_3 e^{j \theta}.
\end{aligned}
This provides us with a nice compact representation of the radial unit vector
\label{eqn:amomentum:240}
\rcap = \Be_3 e^{j \theta}.
Just as was the case in cylindrical coordinates, our azimuthal plane unit vector is
\label{eqn:amomentum:280}
\phicap = \Be_2 e^{i\phi}.
Now we want to compute the velocity vector. As was the case in cylindrical coordinates, we have
\label{eqn:amomentum:300}
\Bv = \dot{r} \rcap + r \dot{\rcap},
but now we need the spherical representation for the $$\rcap$$ derivative, which is
\label{eqn:amomentum:320}
\begin{aligned}
\dot{\rcap}
&=
\PD{\theta}{\rcap} \dot{\theta} + \PD{\phi}{\rcap} \dot{\phi} \\
&=
\Be_3 e^{j\theta} j \dot{\theta} + \Be_3 \sin\theta \PD{\phi}{j} \dot{\phi} \\
&=
\rcap j \dot{\theta} + \Be_3 \sin\theta j i \dot{\phi}.
\end{aligned}
We can reduce the second multivector term without too much work
\label{eqn:amomentum:340}
\begin{aligned}
\Be_3 j i
&=
\Be_3 \Be_{31} e^{i\phi} i \\
&=
\Be_3 \Be_{31} i e^{i\phi} \\
&=
\Be_{33112} e^{i\phi} \\
&=
\Be_{2} e^{i\phi} \\
&= \phicap,
\end{aligned}
so we have
\label{eqn:amomentum:360}
\dot{\rcap}
=
\rcap j \dot{\theta} + \sin\theta \phicap \dot{\phi}.
The velocity is
\label{eqn:amomentum:380}
\Bv = \dot{r} \rcap + r \lr{ \rcap j \dot{\theta} + \sin\theta \phicap \dot{\phi} }.
Now we can finally compute the angular momentum bivector, which is
\label{eqn:amomentum:400}
\begin{aligned}
L &=
\Br \wedge \Bp \\
&=
m r \rcap \wedge \lr{ \dot{r} \rcap + r \lr{ \rcap j \dot{\theta} + \sin\theta \phicap \dot{\phi} } } \\
&=
m r^2 \rcap \wedge \lr{ \rcap j \dot{\theta} + \sin\theta \phicap \dot{\phi} } \\
&=
m r^2 \gpgradetwo{ \rcap \lr{ \rcap j \dot{\theta} + \sin\theta \phicap \dot{\phi} } },
\end{aligned}
which is just
\label{eqn:amomentum:420}
L =
m r^2 \lr{ j \dot{\theta} + \sin\theta \rcap \phicap \dot{\phi} }.
I was slightly surprised by this result, as I naively expected the cylindrical coordinate result. We have a $$m r^2 \rcap \phicap \dot{\phi}$$ term, as was the case in cylindrical coordinates, but scaled down with a $$\sin\theta$$ factor. However, this result does make sense. Consider for example, some fixed circular motion with $$\theta = \mathrm{constant}$$, as sketched in fig. 5.
fig. 5. Circular motion for constant theta
The radius of this circle is actually $$r \sin\theta$$, so the total angular momentum for that motion is scaled down to $$m r^2 \sin\theta \dot{\phi}$$, smaller than the maximum circular angular momentum of $$m r^2 \dot{\phi}$$ which occurs in the $$\theta = \pi/2$$ azimuthal plane. Similarly, if we have circular motion in the “j-plane”, sketched in fig. 6.
fig. 6. Circular motion for constant phi.
where $$\phi = \mathrm{constant}$$, then our angular momentum is $$L = m r^2 j \dot{\theta}$$.
## Gradient, divergence, curl and Laplacian in cylindrical coordinates
In class it was suggested that the identity
\label{eqn:laplacianCylindrical:20}
can be used to compute the Laplacian in non-rectangular coordinates. Is that the easiest way to do this?
\label{eqn:laplacianCylindrical:80}
\spacegrad = \rhocap \partial_\rho + \frac{\phicap}{\rho} \partial_\phi + \zcap \partial_z,
where
\label{eqn:laplacianCylindrical:100}
\begin{aligned}
\rhocap &= \Be_1 e^{\Be_1 \Be_2 \phi} \\
\phicap &= \Be_2 e^{\Be_1 \Be_2 \phi} \\
\end{aligned}
Taking $$\phi$$ derivatives of \ref{eqn:laplacianCylindrical:100}, we have
\label{eqn:laplacianCylindrical:120}
\begin{aligned}
\partial_\phi \rhocap &= \Be_1 \Be_1 \Be_2 e^{\Be_1 \Be_2 \phi} = \Be_2 e^{\Be_1 \Be_2 \phi} = \phicap \\
\partial_\phi \phicap &= \Be_2 \Be_1 \Be_2 e^{\Be_1 \Be_2 \phi} = -\Be_1 e^{\Be_1 \Be_2 \phi} = -\rhocap.
\end{aligned}
The gradient of a vector $$\BA = \rhocap A_\rho + \phicap A_\phi + \zcap A_z$$ is
\label{eqn:laplacianCylindrical:60}
\begin{aligned}
&=
\lr{ \rhocap \partial_\rho + \frac{\phicap}{\rho} \partial_\phi + \zcap \partial_z }
\lr{ \rhocap A_\rho + \phicap A_\phi + \zcap A_z } \\
&=
\quad \rhocap \partial_\rho \lr{ \rhocap A_\rho + \phicap A_\phi + \zcap A_z } \\
&\quad + \frac{\phicap}{\rho} \partial_\phi \lr{ \rhocap A_\rho + \phicap A_\phi + \zcap A_z } \\
&\quad + \zcap \partial_z \lr{ \rhocap A_\rho + \phicap A_\phi + \zcap A_z } \\
&=
\quad \rhocap \lr{ \rhocap \partial_\rho A_\rho + \phicap \partial_\rho A_\phi + \zcap \partial_\rho A_z } \\
&\quad + \frac{\phicap}{\rho} \lr{ \partial_\phi(\rhocap A_\rho) + \partial_\phi(\phicap A_\phi) + \zcap \partial_\phi A_z } \\
&\quad + \zcap \lr{ \rhocap \partial_z A_\rho + \phicap \partial_z A_\phi + \zcap \partial_z A_z } \\
&=
\quad \partial_\rho A_\rho + \rhocap \phicap \partial_\rho A_\phi + \rhocap \zcap \partial_\rho A_z \\
&\quad +\frac{1}{\rho} \lr{ A_\rho + \phicap \rhocap \partial_\phi A_\rho – \phicap \rhocap A_\phi + \partial_\phi A_\phi + \phicap \zcap \partial_\phi A_z } \\
&\quad + \zcap \rhocap \partial_z A_\rho + \zcap \phicap \partial_z A_\phi + \partial_z A_z \\
&=
\quad \partial_\rho A_\rho + \frac{1}{\rho} \lr{ A_\rho + \partial_\phi A_\phi } + \partial_z A_z \\
\zcap \rhocap \lr{
\partial_z A_\rho
-\partial_\rho A_z
} \\
\phicap \zcap \lr{
\inv{\rho} \partial_\phi A_z
– \partial_z A_\phi
} \\
\rhocap \phicap \lr{
\partial_\rho A_\phi
– \inv{\rho} \lr{ \partial_\phi A_\rho – A_\phi }
},
\end{aligned}
As expected, we see that the gradient splits nicely into a dot and curl
\label{eqn:laplacianCylindrical:160}
\begin{aligned}
&= \spacegrad \cdot \BA + \rhocap \phicap \zcap (\spacegrad \cross \BA ),
\end{aligned}
where the cylindrical representation of the divergence is seen to be
\label{eqn:laplacianCylindrical:140}
=
\inv{\rho} \partial_\rho (\rho A_\rho) + \frac{1}{\rho} \partial_\phi A_\phi + \partial_z A_z,
and the cylindrical representation of the curl is
\label{eqn:laplacianCylindrical:180}
=
\rhocap
\lr{
\inv{\rho} \partial_\phi A_z
– \partial_z A_\phi
}
+
\phicap
\lr{
\partial_z A_\rho
-\partial_\rho A_z
}
+
\inv{\rho} \zcap \lr{
\partial_\rho ( \rho A_\phi )
– \partial_\phi A_\rho
}.
Should we want to, it is now possible to evaluate the Laplacian of $$\BA$$ using
\ref{eqn:laplacianCylindrical:20}
, which will have the following components
\label{eqn:laplacianCylindrical:220}
\begin{aligned}
\rhocap \cdot \lr{ \spacegrad^2 \BA }
&=
\partial_\rho
\lr{
\inv{\rho} \partial_\rho (\rho A_\rho) + \frac{1}{\rho} \partial_\phi A_\phi + \partial_z A_z
}
\lr{
\inv{\rho} \partial_\phi \lr{
\inv{\rho} \lr{
\partial_\rho ( \rho A_\phi ) – \partial_\phi A_\rho
}
}
– \partial_z \lr{
\partial_z A_\rho -\partial_\rho A_z
}
} \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho (\rho A_\rho)}
+ \partial_\rho \lr{ \frac{1}{\rho} \partial_\phi A_\phi}
+ \partial_{\rho z} A_z
– \inv{\rho^2}\partial_{\phi \rho} ( \rho A_\phi )
+ \inv{\rho^2}\partial_{\phi\phi} A_\rho
+ \partial_{zz} A_\rho
– \partial_{z\rho} A_z \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho (\rho A_\rho)}
+ \inv{\rho^2}\partial_{\phi\phi} A_\rho
+ \partial_{zz} A_\rho
– \frac{1}{\rho^2} \partial_\phi A_\phi
+ \frac{1}{\rho} \partial_{\rho\phi} A_\phi
– \inv{\rho^2}\partial_{\phi} A_\phi
– \inv{\rho}\partial_{\phi\rho} A_\phi \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho (\rho A_\rho)}
+ \inv{\rho^2}\partial_{\phi\phi} A_\rho
+ \partial_{zz} A_\rho
– \frac{2}{\rho^2} \partial_\phi A_\phi \\
&=
\inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\rho}
+ \inv{\rho^2}\partial_{\phi\phi} A_\rho
+ \partial_{zz} A_\rho
– \frac{A_\rho}{\rho^2}
– \frac{2}{\rho^2} \partial_\phi A_\phi,
\end{aligned}
\label{eqn:laplacianCylindrical:240}
\begin{aligned}
\phicap \cdot \lr{ \spacegrad^2 \BA }
&=
\inv{\rho} \partial_\phi
\lr{
\inv{\rho} \partial_\rho (\rho A_\rho) + \frac{1}{\rho} \partial_\phi A_\phi + \partial_z A_z
}
\lr{
\lr{
\partial_z \lr{
\inv{\rho} \partial_\phi A_z – \partial_z A_\phi
}
-\partial_\rho \lr{
\inv{\rho} \lr{ \partial_\rho ( \rho A_\phi ) – \partial_\phi A_\rho}
}
}
} \\
&=
\inv{\rho^2} \partial_{\phi\rho} (\rho A_\rho)
+ \frac{1}{\rho^2} \partial_{\phi\phi} A_\phi
+ \inv{\rho}\partial_{\phi z} A_z
– \inv{\rho} \partial_{z\phi} A_z
+ \partial_{z z} A_\phi
+\partial_\rho \lr{ \inv{\rho} \partial_\rho ( \rho A_\phi ) }
– \partial_\rho \lr{ \inv{\rho} \partial_\phi A_\rho} \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho ( \rho A_\phi ) }
+ \frac{1}{\rho^2} \partial_{\phi\phi} A_\phi
+ \partial_{z z} A_\phi
+ \inv{\rho^2} \partial_{\phi\rho} (\rho A_\rho)
+ \inv{\rho}\partial_{\phi z} A_z
– \inv{\rho} \partial_{z\phi} A_z
– \partial_\rho \lr{ \inv{\rho} \partial_\phi A_\rho} \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho ( \rho A_\phi ) }
+ \frac{1}{\rho^2} \partial_{\phi\phi} A_\phi
+ \partial_{z z} A_\phi
+ \inv{\rho^2} \partial_{\phi} A_\rho
+ \inv{\rho} \partial_{\phi\rho} A_\rho
+ \inv{\rho^2} \partial_\phi A_\rho
– \inv{\rho} \partial_{\rho\phi} A_\rho \\
&=
\partial_\rho \lr{ \inv{\rho} \partial_\rho ( \rho A_\phi ) }
+ \frac{1}{\rho^2} \partial_{\phi\phi} A_\phi
+ \partial_{z z} A_\phi
+ \frac{2}{\rho^2} \partial_{\phi} A_\rho \\
&=
\inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\phi }
+ \frac{1}{\rho^2} \partial_{\phi\phi} A_\phi
+ \partial_{z z} A_\phi
+ \frac{2}{\rho^2} \partial_{\phi} A_\rho
– \frac{A_\phi}{\rho^2},
\end{aligned}
\label{eqn:laplacianCylindrical:260}
\begin{aligned}
\zcap \cdot \lr{ \spacegrad^2 \BA }
&=
\partial_z
\lr{
\inv{\rho} \partial_\rho (\rho A_\rho) + \frac{1}{\rho} \partial_\phi A_\phi + \partial_z A_z
}
\inv{\rho} \lr{
\partial_\rho \lr{ \rho \lr{
\partial_z A_\rho -\partial_\rho A_z
}
}
– \partial_\phi \lr{
\inv{\rho} \partial_\phi A_z – \partial_z A_\phi
}
} \\
&=
\inv{\rho} \partial_{z\rho} (\rho A_\rho)
+ \frac{1}{\rho} \partial_{z\phi} A_\phi
+ \partial_{zz} A_z
– \inv{\rho}\partial_\rho \lr{ \rho \partial_z A_\rho }
+ \inv{\rho}\partial_\rho \lr{ \rho \partial_\rho A_z }
+ \inv{\rho^2} \partial_{\phi\phi} A_z
– \inv{\rho} \partial_{\phi z} A_\phi \\
&=
\inv{\rho}\partial_\rho \lr{ \rho \partial_\rho A_z }
+ \inv{\rho^2} \partial_{\phi\phi} A_z
+ \partial_{zz} A_z
+ \inv{\rho} \partial_{z} A_\rho
+\partial_{z\rho} A_\rho
+ \frac{1}{\rho} \partial_{z\phi} A_\phi
– \inv{\rho}\partial_z A_\rho
– \partial_{\rho z} A_\rho
– \inv{\rho} \partial_{\phi z} A_\phi \\
&=
\inv{\rho}\partial_\rho \lr{ \rho \partial_\rho A_z }
+ \inv{\rho^2} \partial_{\phi\phi} A_z
+ \partial_{zz} A_z
\end{aligned}
Evaluating these was a fairly tedious and mechanical job, and would have been better suited to a computer algebra system than by hand as done here.
### Explicit cylindrical Laplacian
Let’s try this a different way. The most obvious potential strategy is to just apply the Laplacian to the vector itself, but we need to include the unit vectors in such an operation
\label{eqn:laplacianCylindrical:280}
\spacegrad^2 \lr{ \rhocap A_\rho + \phicap A_\phi + \zcap A_z }.
First we need to know the explicit form of the cylindrical Laplacian. From the painful expansion, we can guess that it is
\label{eqn:laplacianCylindrical:300}
=
\inv{\rho}\partial_\rho \lr{ \rho \partial_\rho \psi }
+ \inv{\rho^2} \partial_{\phi\phi} \psi
+ \partial_{zz} \psi.
Let’s check that explicitly. Here I use the vector product where $$\rhocap^2 = \phicap^2 = \zcap^2 = 1$$, and these vectors anticommute when different
\label{eqn:laplacianCylindrical:320}
\begin{aligned}
&=
\lr{ \rhocap \partial_\rho + \frac{\phicap}{\rho} \partial_\phi + \zcap \partial_z }
\lr{ \rhocap \partial_\rho \psi + \frac{\phicap}{\rho} \partial_\phi \psi + \zcap \partial_z \psi } \\
&=
\rhocap \partial_\rho
\lr{ \rhocap \partial_\rho \psi + \frac{\phicap}{\rho} \partial_\phi \psi + \zcap \partial_z \psi }
+ \frac{\phicap}{\rho} \partial_\phi
\lr{ \rhocap \partial_\rho \psi + \frac{\phicap}{\rho} \partial_\phi \psi + \zcap \partial_z \psi }
+ \zcap \partial_z
\lr{ \rhocap \partial_\rho \psi + \frac{\phicap}{\rho} \partial_\phi \psi + \zcap \partial_z \psi } \\
&=
\partial_{\rho\rho} \psi
+ \rhocap \phicap \partial_\rho \lr{ \frac{1}{\rho} \partial_\phi \psi}
+ \rhocap \zcap \partial_{\rho z} \psi
+ \frac{\phicap}{\rho} \partial_\phi \lr{ \rhocap \partial_\rho \psi }
+ \frac{\phicap}{\rho} \partial_\phi \lr{ \frac{\phicap}{\rho} \partial_\phi \psi }
+ \frac{\phicap \zcap }{\rho} \partial_{\phi z} \psi
+ \zcap \rhocap \partial_{z\rho} \psi
+ \frac{\zcap \phicap}{\rho} \partial_{z\phi} \psi
+ \partial_{zz} \psi \\
&=
\partial_{\rho\rho} \psi
+ \inv{\rho} \partial_\rho \psi
+ \frac{1}{\rho^2} \partial_{\phi \phi} \psi
+ \partial_{zz} \psi
+ \rhocap \phicap
\lr{
-\frac{1}{\rho^2} \partial_\phi \psi
+\frac{1}{\rho} \partial_{\rho \phi} \psi
-\inv{\rho} \partial_{\phi \rho} \psi
+ \frac{1}{\rho^2} \partial_\phi \psi
}
+ \zcap \rhocap \lr{
-\partial_{\rho z} \psi
+ \partial_{z\rho} \psi
}
+ \phicap \zcap \lr{
\inv{\rho} \partial_{\phi z} \psi
– \inv{\rho} \partial_{z\phi} \psi
} \\
&=
\partial_{\rho\rho} \psi
+ \inv{\rho} \partial_\rho \psi
+ \frac{1}{\rho^2} \partial_{\phi \phi} \psi
+ \partial_{zz} \psi,
\end{aligned}
so the Laplacian operator is
\label{eqn:laplacianCylindrical:340}
\boxed{
=
\inv{\rho} \PD{\rho}{} \lr{ \rho \PD{\rho}{} }
+ \frac{1}{\rho^2} \PDSq{\phi}{}
+ \PDSq{z}{}.
}
All the bivector grades of the Laplacian operator are seen to explicitly cancel, regardless of the grade of $$\psi$$, just as if we had expanded the scalar Laplacian as a dot product
$$\spacegrad^2 \psi = \spacegrad \cdot \lr{ \spacegrad \psi}$$.
Unlike such a scalar expansion, this derivation is seen to be valid for any grade $$\psi$$. We know now that we can trust this result when $$\psi$$ is a scalar, a vector, a bivector, a trivector, or even a multivector.
### Vector Laplacian
Now that we trust that the typical scalar form of the Laplacian applies equally well to multivectors as it does to scalars, that cylindrical coordinate operator can now be applied to a
vector. Consider the projections onto each of the directions in turn
\label{eqn:laplacianCylindrical:360}
=
\rhocap \inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\rho }
+ \frac{1}{\rho^2} \partial_{\phi\phi} \lr{\rhocap A_\rho}
+ \rhocap \partial_{zz} A_\rho
\label{eqn:laplacianCylindrical:380}
\begin{aligned}
\partial_{\phi\phi} \lr{\rhocap A_\rho}
&=
\partial_\phi \lr{ \phicap A_\rho + \rhocap \partial_\phi A_\rho } \\
&=
-\rhocap A_\rho
+\phicap \partial_\phi A_\rho
+ \phicap \partial_\phi A_\rho
+ \rhocap \partial_{\phi\phi} A_\rho \\
&=
\rhocap \lr{ \partial_{\phi\phi} A_\rho -A_\rho }
+ 2 \phicap \partial_\phi A_\rho
\end{aligned}
so this component of the vector Laplacian is
\label{eqn:laplacianCylindrical:400}
\begin{aligned}
&=
\rhocap
\lr{
\inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\rho }
+ \inv{\rho^2} \partial_{\phi\phi} A_\rho
– \inv{\rho^2} A_\rho
+ \partial_{zz} A_\rho
}
+
\phicap
\lr{
2 \inv{\rho^2} \partial_\phi A_\rho
} \\
&=
\rhocap \lr{
– \inv{\rho^2} A_\rho
}
+
\phicap
\frac{2}{\rho^2} \partial_\phi A_\rho
.
\end{aligned}
The Laplacian for the projection of the vector onto the $$\phicap$$ direction is
\label{eqn:laplacianCylindrical:420}
=
\phicap \inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\phi }
+ \frac{1}{\rho^2} \partial_{\phi\phi} \lr{\phicap A_\phi}
+ \phicap \partial_{zz} A_\phi,
Again, since the unit vectors are $$\phi$$ dependent, the $$\phi$$ derivatives have to be treated carefully
\label{eqn:laplacianCylindrical:440}
\begin{aligned}
\partial_{\phi\phi} \lr{\phicap A_\phi}
&=
\partial_{\phi} \lr{-\rhocap A_\phi + \phicap \partial_\phi A_\phi} \\
&=
-\phicap A_\phi
-\rhocap \partial_\phi A_\phi
– \rhocap \partial_\phi A_\phi
+ \phicap \partial_{\phi \phi} A_\phi \\
&=
– 2 \rhocap \partial_\phi A_\phi
+
\phicap
\lr{
\partial_{\phi \phi} A_\phi
– A_\phi
},
\end{aligned}
so the Laplacian of this projection is
\label{eqn:laplacianCylindrical:460}
\begin{aligned}
&=
\phicap
\lr{
\inv{\rho} \partial_\rho \lr{ \rho \partial_\rho A_\phi }
+ \phicap \partial_{zz} A_\phi,
\inv{\rho^2} \partial_{\phi \phi} A_\phi
– \frac{A_\phi }{\rho^2}
}
– \rhocap \frac{2}{\rho^2} \partial_\phi A_\phi \\
&=
\phicap \lr{
– \frac{A_\phi}{\rho^2}
}
– \rhocap \frac{2}{\rho^2} \partial_\phi A_\phi.
\end{aligned}
Since $$\zcap$$ is fixed we have
\label{eqn:laplacianCylindrical:480}
=
Putting all the pieces together we have
\label{eqn:laplacianCylindrical:500}
\boxed{
=
\rhocap \lr{
– \inv{\rho^2} A_\rho
– \frac{2}{\rho^2} \partial_\phi A_\phi
}
+\phicap \lr{
– \frac{A_\phi}{\rho^2}
+ \frac{2}{\rho^2} \partial_\phi A_\rho
}
+
}
This matches the results of \ref{eqn:laplacianCylindrical:220}, …, from the painful expansion of
$$\spacegrad \lr{ \spacegrad \cdot \BA } – \spacegrad \cross \lr{ \spacegrad \cross \BA }$$.
## Line charge field and potential.
When computing the most general solution of the electrostatic potential in a plane, Jackson [1] mentions that $$-2 \lambda_0 \ln \rho$$ is the well known potential for an infinite line charge (up to the unit specific factor). Checking that statement, since I didn’t recall what that potential was offhand, I encountered some inconsistencies and non-convergent integrals, and thought it was worthwhile to explore those a bit more carefully. This will be done here.
### Using Gauss’s law.
For an infinite length line charge, we can find the radial field contribution using Gauss’s law, imagining a cylinder of length $$\Delta l$$ of radius $$\rho$$ surrounding this charge with the midpoint at the origin. Ignoring any non-radial field contribution, we have
\label{eqn:lineCharge:20}
\int_{-\Delta l/2}^{\Delta l/2} \ncap \cdot \BE (2 \pi \rho) dl = \frac{\lambda_0}{\epsilon_0} \Delta l,
or
\label{eqn:lineCharge:40}
\BE = \frac{\lambda_0}{2 \pi \epsilon_0} \frac{\rhocap}{\rho}.
Since
\label{eqn:lineCharge:60}
this means that the potential is
\label{eqn:lineCharge:80}
\phi = -\frac{2 \lambda_0}{4 \pi \epsilon_0} \ln \rho.
### Finite line charge potential.
Let’s try both these calculations for a finite charge distribution. Gauss’s law looses its usefulness, but we can evaluate the integrals directly. For the electric field
\label{eqn:lineCharge:100}
\BE
= \frac{\lambda_0}{4 \pi \epsilon_0} \int \frac{(\Bx – \Bx’)}{\Abs{\Bx – \Bx’}^3} dl’.
Using cylindrical coordinates with the field point $$\Bx = \rho \rhocap$$ for convience, the charge point $$\Bx’ = z’ \zcap$$, and a the charge distributed over $$[a,b]$$ this is
\label{eqn:lineCharge:120}
\BE
= \frac{\lambda_0}{4 \pi \epsilon_0} \int_a^b \frac{(\rho \rhocap – z’ \zcap)}{\lr{\rho^2 + (z’)^2}^{3/2}} dz’.
When the charge is uniformly distributed around the origin $$[a,b] = b[-1,1]$$ the $$\zcap$$ component of this field is killed because the integrand is odd. This justifies ignoring such contributions in the Gaussing cylinder analysis above. The general solution to this integral is found to be
\label{eqn:lineCharge:140}
\BE
=
\frac{\lambda_0}{4 \pi \epsilon_0}
\evalrange{
\lr{
\frac{z’ \rhocap }{\rho \sqrt{ \rho^2 + (z’)^2 } }
+\frac{\zcap}{ \sqrt{ \rho^2 + (z’)^2 } }
}
}{a}{b},
or
\label{eqn:lineCharge:240}
\boxed{
\BE
=
\frac{\lambda_0}{4 \pi \epsilon_0}
\lr{
\frac{\rhocap }{\rho}
\lr{
\frac{b}{\sqrt{ \rho^2 + b^2 } }
-\frac{a}{\sqrt{ \rho^2 + a^2 } }
}
+ \zcap
\lr{
\frac{1}{ \sqrt{ \rho^2 + b^2 } }
-\frac{1}{ \sqrt{ \rho^2 + a^2 } }
}
}.
}
When $$b = -a = \Delta l/2$$, this reduces to
\label{eqn:lineCharge:160}
\BE
=
\frac{\lambda_0}{4 \pi \epsilon_0}
\frac{\rhocap }{\rho}
\frac{\Delta l}{\sqrt{ \rho^2 + (\Delta l/2)^2 } },
which further reduces to \ref{eqn:lineCharge:40} when $$\Delta l \gg \rho$$.
### Finite line charge potential. Wrong but illuminating.
Again, putting the field point at $$z’ = 0$$, we have
\label{eqn:lineCharge:180}
\phi(\rho)
= \frac{\lambda_0}{4 \pi \epsilon_0} \int_a^b \frac{dz’}{\lr{\rho^2 + (z’)^2}^{1/2}},
which integrates to
\label{eqn:lineCharge:260}
\phi(\rho)
= \frac{\lambda_0}{4 \pi \epsilon_0 }
\ln \frac{ b + \sqrt{ \rho^2 + b^2 }}{ a + \sqrt{\rho^2 + a^2}}.
With $$b = -a = \Delta l/2$$, this approaches
\label{eqn:lineCharge:200}
\phi
\approx
\frac{\lambda_0}{4 \pi \epsilon_0 }
\ln \frac{ (\Delta l/2) }{ \rho^2/2\Abs{\Delta l/2}}
=
\frac{-2 \lambda_0}{4 \pi \epsilon_0 } \ln \rho
+
\frac{\lambda_0}{4 \pi \epsilon_0 }
\ln \lr{ (\Delta l)^2/2 }.
Before $$\Delta l$$ is allowed to tend to infinity, this is identical (up to a difference in the reference potential) to \ref{eqn:lineCharge:80} found using Gauss’s law. It is, strictly speaking, singular when $$\Delta l \rightarrow \infty$$, so it does not seem right to infinity as a reference point for the potential.
There’s another weird thing about this result. Since this has no $$z$$ dependence, it is not obvious how we would recover the non-radial portion of the electric field from this potential using $$\BE = -\spacegrad \phi$$? Let’s calculate the elecric field from \ref{eqn:lineCharge:180} explicitly
\label{eqn:lineCharge:220}
\begin{aligned}
\BE
&=
-\frac{\lambda_0}{4 \pi \epsilon_0}
\ln \frac{ b + \sqrt{ \rho^2 + b^2 }}{ a + \sqrt{\rho^2 + a^2}} \\
&=
-\frac{\lambda_0 \rhocap}{4 \pi \epsilon_0 }
\PD{\rho}{}
\ln \frac{ b + \sqrt{ \rho^2 + b^2 }}{ a + \sqrt{\rho^2 + a^2}} \\
&=
-\frac{\lambda_0 \rhocap}{4 \pi \epsilon_0}
\lr{
\inv{ b + \sqrt{ \rho^2 + b^2 }} \frac{ \rho }{\sqrt{ \rho^2 + b^2 }}
-\inv{ a + \sqrt{ \rho^2 + a^2 }} \frac{ \rho }{\sqrt{ \rho^2 + a^2 }}
} \\
&=
-\frac{\lambda_0 \rhocap}{4 \pi \epsilon_0 \rho}
\lr{
\frac{ -b + \sqrt{ \rho^2 + b^2 }}{\sqrt{ \rho^2 + b^2 }}
-\frac{ -a + \sqrt{ \rho^2 + a^2 }}{\sqrt{ \rho^2 + a^2 }}
} \\
&=
\frac{\lambda_0 \rhocap}{4 \pi \epsilon_0 \rho}
\lr{
\frac{ b }{\sqrt{ \rho^2 + b^2 }}
-\frac{ a }{\sqrt{ \rho^2 + a^2 }}
}.
\end{aligned}
This recovers the radial component of the field from \ref{eqn:lineCharge:240}, but where did the $$\zcap$$ component go? The required potential appears to be
\label{eqn:lineCharge:340}
\phi(\rho, z)
=
\frac{\lambda_0}{4 \pi \epsilon_0 }
\ln \frac{ b + \sqrt{ \rho^2 + b^2 }}{ a + \sqrt{\rho^2 + a^2}}
\frac{z \lambda_0}{4 \pi \epsilon_0 }
\lr{ \frac{1}{\sqrt{\rho^2 + b^2}}
-\frac{1}{\sqrt{\rho^2 + a^2}}
}.
When computing the electric field $$\BE(\rho, \theta, z)$$, it was convienent to pick the coordinate system so that $$z = 0$$. Doing this with the potential gives the wrong answers. The reason for this appears to be that this kills the potential term that is linear in $$z$$ before taking its gradient, and we need that term to have the $$\zcap$$ field component that is expected for a charge distribution that is non-symmetric about the origin on the z-axis!
### Finite line charge potential. Take II.
Let the point at which the potential is evaluated be
\label{eqn:lineCharge:360}
\Bx = \rho \rhocap + z \zcap,
and the charge point be
\label{eqn:lineCharge:380}
\Bx’ = z’ \zcap.
This gives
\label{eqn:lineCharge:400}
\begin{aligned}
\phi(\rho, z)
&= \frac{\lambda_0}{4\pi \epsilon_0} \int_a^b \frac{dz’}{\Abs{\rho^2 + (z – z’)^2 }} \\
&= \frac{\lambda_0}{4\pi \epsilon_0} \int_{a-z}^{b-z} \frac{du}{ \Abs{\rho^2 + u^2} } \\
&= \frac{\lambda_0}{4\pi \epsilon_0}
\evalrange{\ln \lr{ u + \sqrt{ \rho^2 + u^2 }}}{b-z}{a-z} \\
&=
\frac{\lambda_0}{4\pi \epsilon_0}
\ln \frac
{ b-z + \sqrt{ \rho^2 + (b-z)^2 }}
{ a-z + \sqrt{ \rho^2 + (a-z)^2 }}.
\end{aligned}
The limit of this potential $$a = -\Delta/2 \rightarrow -\infty, b = \Delta/2 \rightarrow \infty$$ doesn’t exist in any strict sense. If we are cavilier about the limits, as in \ref{eqn:lineCharge:200}, this can be evaluated as
\label{eqn:lineCharge:n}
\phi \approx
\frac{\lambda_0}{4\pi \epsilon_0} \lr{ -2 \ln \rho + \textrm{constant} }.
however, the constant ($$\ln \Delta^2/2$$) is infinite, so there isn’t really a good justification for using that constant as the potential reference point directly.
It seems that the “right” way to calculate the potential for the infinite distribution, is to
• Calculate the field from the potential.
• Take the PV limit of that field with the charge distribution extending to infinity.
• Compute the corresponding potential from this limiting value of the field.
Doing that doesn’t blow up. That field calculation, for the finite case, should include a $$\zcap$$ component. To verify, let’s take the respective derivatives
\label{eqn:lineCharge:420}
\begin{aligned}
-\PD{z}{} \phi
&=
-\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\frac{ -1 + \frac{z – b}{\sqrt{ \rho^2 + (b-z)^2 }} }{
b-z + \sqrt{ \rho^2 + (b-z)^2 }
}
\frac{ -1 + \frac{z – a}{\sqrt{ \rho^2 + (a-z)^2 }} }{
a-z + \sqrt{ \rho^2 + (a-z)^2 }
}
} \\
&=
\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\frac{ 1 + \frac{b – z}{\sqrt{ \rho^2 + (b-z)^2 }} }{
b-z + \sqrt{ \rho^2 + (b-z)^2 }
}
\frac{ 1 + \frac{a – z}{\sqrt{ \rho^2 + (a-z)^2 }} }{
a-z + \sqrt{ \rho^2 + (a-z)^2 }
}
} \\
&=
\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\inv{\sqrt{ \rho^2 + (b-z)^2 }}
-\inv{\sqrt{ \rho^2 + (a-z)^2 }}
},
\end{aligned}
and
\label{eqn:lineCharge:440}
\begin{aligned}
-\PD{\rho}{} \phi
&=
-\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\frac{ \frac{\rho}{\sqrt{ \rho^2 + (b-z)^2 }} }{
b-z + \sqrt{ \rho^2 + (b-z)^2 }
}
\frac{ \frac{\rho}{\sqrt{ \rho^2 + (a-z)^2 }} }{
a-z + \sqrt{ \rho^2 + (a-z)^2 }
}
} \\
&=
-\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\frac{\rho \lr{
-(b-z) + \sqrt{ \rho^2 + (b-z)^2 }
}}{ \rho^2 \sqrt{ \rho^2 + (b-z)^2 } }
\frac{\rho \lr{
-(a-z) + \sqrt{ \rho^2 + (a-z)^2 }
}}{ \rho^2 \sqrt{ \rho^2 + (a-z)^2 } }
} \\
&=
\frac{\lambda_0}{4\pi \epsilon_0 \rho}
\lr{
\frac{b-z}{\sqrt{ \rho^2 + (b-z)^2 }}
-\frac{a-z}{\sqrt{ \rho^2 + (a-z)^2 }}
}
.
\end{aligned}
Putting the pieces together, the electric field is
\label{eqn:lineCharge:460}
\BE =
\frac{\lambda_0}{4\pi \epsilon_0}
\lr{
\frac{\rhocap}{\rho} \lr{
\frac{b-z}{\sqrt{ \rho^2 + (b-z)^2 }}
-\frac{a-z}{\sqrt{ \rho^2 + (a-z)^2 }}
}
+
\zcap \lr{
\inv{\sqrt{ \rho^2 + (b-z)^2 }}
-\inv{\sqrt{ \rho^2 + (a-z)^2 }}
}
}.
For has a PV limit of \ref{eqn:lineCharge:40} at $$z = 0$$, and also for the finite case, has the $$\zcap$$ field component that was obtained when the field was obtained by direct integration.
### Conclusions
• We have to evaluate the potential at all points in space, not just on the axis that we evaluate the field on (should we choose to do so).
• In this case, we found that it was not directly meaningful to take the limit of a potential distribution. We can, however, compute the field from a potential for a finite charge distribution,
take the limit of that field, and then calculate the corresponding potential for the infinite distribution.
Is there a more robust mechanism that can be used to directly calculate the potential for an infinite charge distribution, instead of calculating the potential from the field of such an infinite distribution?
I think that were things go wrong is that the integral of \ref{eqn:lineCharge:180} does not apply to charge distributions that are not finite on the infinite range $$z \in [-\infty, \infty]$$. That solution was obtained by utilizing an all-space Green’s function, and the boundary term in that Green’s analysis was assumed to tend to zero. That isn’t the case when the charge distribution is $$\lambda_0 \delta( z )$$.
# References
[1] JD Jackson. Classical Electrodynamics. John Wiley and Sons, 2nd edition, 1975.
## Coupled wave equation in cylindrical coordinates
In [1], for a sourceless configuration, it is noted that the electric field equations $$\spacegrad^2 \BE = -\beta^2 \BE$$ have the form
\label{eqn:cylindricalFieldSolution:20}
\spacegrad^2 E_\rho – \frac{E_\rho}{\rho^2} – \frac{2}{\rho^2} \PD{\phi}{E_\phi} = -\beta^2 E_\rho
\label{eqn:cylindricalFieldSolution:60}
\spacegrad^2 E_\phi – \frac{E_\phi}{\rho^2} + \frac{2}{\rho^2} \PD{\phi}{E_\rho} = -\beta^2 E_\phi
\label{eqn:cylindricalFieldSolution:80}
where
\label{eqn:cylindricalFieldSolution:100}
\inv{\rho} \PD{\rho}{} \lr{ \rho \PD{\rho}{\psi}} + \inv{\rho^2}\PDSq{\phi}{\psi} + \PDSq{z}{\psi}.
He applies separation of variables to the last equation, ending up with the usual Bessel function solution, but the first two coupled equations are dismissed as coupled and difficult. It looks like separation of variables works for this too, but we have to prep the system slightly by writing $$\psi = E_\rho + j E_\phi$$, which gives
\label{eqn:cylindricalFieldSolution:120}
\spacegrad^2 \psi – \frac{\psi}{\rho^2} + \frac{2 j}{\rho^2} \PD{\phi}{\psi} = -\beta^2 \psi,
or
\label{eqn:cylindricalFieldSolution:140}
\inv{\rho} \PD{\rho}{} \lr{ \rho \PD{\rho}{\psi}} + \inv{\rho^2}\PDSq{\phi}{\psi} + \PDSq{z}{\psi}
– \frac{\psi}{\rho^2} + \frac{2 j}{\rho^2} \PD{\phi}{\psi} = -\beta^2 \psi.
With a separation of variables substitution $$\psi = f(\rho) g(\phi) h(z)$$ this gives
\label{eqn:cylindricalFieldSolution:160}
\inv{\rho f} \PD{\rho}{} \lr{ \rho \PD{\rho}{f}}
+ \inv{\rho^2 g}\PDSq{\phi}{g}
+ \inv{z} \PDSq{z}{h}
– \frac{1}{\rho^2} + \frac{2 j}{\rho^2 g} \PD{\phi}{g} = -\beta^2.
Assuming a solution for the function $$h$$ of
\label{eqn:cylindricalFieldSolution:180}
\inv{z} \PDSq{z}{h} = -\alpha^2,
the PDE is reduced to an equation in two functions
\label{eqn:cylindricalFieldSolution:200}
\inv{\rho f} \PD{\rho}{} \lr{ \rho \PD{\rho}{f}}
+ \inv{\rho^2 g}\PD{\phi}{} \lr{ g + 2 j g}
+ \beta^2 -\alpha^2
– \frac{1}{\rho^2}
= 0,
or
\label{eqn:cylindricalFieldSolution:220}
\frac{\rho}{f} \PD{\rho}{} \lr{ \rho \PD{\rho}{f}}
+ \inv{g}\PD{\phi}{} \lr{ g + 2 j g}
+ \lr{ \beta^2 -\alpha^2 }\rho^2
= 1.
With the term in $$g$$ having only $$\phi$$ dependence, we can assume
\label{eqn:cylindricalFieldSolution:240}
\inv{g}\PD{\phi}{} \lr{ g + 2 j g} = 1 – \gamma^2,
for
\label{eqn:cylindricalFieldSolution:260}
\frac{\rho}{f} \PD{\rho}{} \lr{ \rho \PD{\rho}{f}}
– \gamma^2
+ \lr{ \beta^2 -\alpha^2 }\rho^2
= 0.
I’m not sure off hand if these can be solved in known special functions, especially since the constants in the mix are complex.
# References
[1] Constantine A Balanis. Advanced engineering electromagnetics, volume 20. Wiley New York, 1989.
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|
https://web2.0calc.com/questions/help_74517
|
+0
Help :)
0
46
2
If x, y, and z are positive integers such that 6xyz+30xy+21xz+2yz+105x+10y+7z=812, find x+y+z.
Mar 3, 2020
#2
+111
+1
$$\displaystyle 6xyz +30xy+21xz+2yz+105x+10y+7z=812.$$
Factorise.
$$\displaystyle (3x+1)(2y+7)(z+5)=812 = 2\times 2\times7\times29.$$
The only x, y, z that fit are x =1, y = 11 and z = 2, so x + y + z = 14.
Mar 4, 2020
|
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|
https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=148&tabname=Equilateral%20Tutorial
|
### View All »Matching Part Numbers
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# Equilateral Dispersive Prisms
• High Refractive Index
• Low Abbe Vd Number for Maximum Dispersion
• Material: F2, N-SF11, CaF2, or ZnSe
PS854
PS860
PS856
PS861
Application Idea
PS855 Prism on a KM200B
Platform Mount
Related Items
Top-Down Diagram of Dispersive Prism with Two Incident Rays
Our Dispersive Equilateral Prisms, which are fabricated from N-SF11, F2, CaF2, or ZnSe are available in sizes ranging from 10 mm to 50 mm. These prisms create less stray light than diffraction gratings, thereby eliminating the higher order problems typically associated with gratings.
Dispersive prisms are typically used at the minimum angle of deviation. This is the angle for which the wavelength of interest will travel parallel to the base of the prism, and the angle of incidence is equal to the angle of refraction when measured with respect to the normal of the prism face at the respective interface (see the Equilateral Tutorial tab for more information). At the minimum angle of deviation, a maximum clear aperture is achieved and reflective loss of P-polarized light is reduced since the angle of incidence is nearly Brewster's angle. For S-polarization, a custom antireflective coating can be used to minimize surface reflections.
Please refer to the Prism Guide tab above for assistance in selecting the appropriate prism for your application, or to view Thorlabs' extensive line of prisms, please click here.
General Specifications
Material F2a N-SF11a CaF2a ZnSea
Clear Aperture 70%
Surface Quality (Scratch-Dig) 40-20 60-40
Angular Tolerance ±5 arcmin ±3 arcmin ±10 arcmin
Number of Polished Faces 2b 3c
• Click Link for Detailed Specifications on the Substrate Glass
• One face and the bases are fine ground.
• The bases are fine ground.
Item # A=B=C=H
(mm)
Material Minimum Angle
of Deviation
Vdb Surface Flatness
@ 633 nm
PS850 10 ± 0.15 F2 47.9° @ 633 nm 36.37 λ/10
PS856 15 ± 0.1
PS858 20 ± 0.1
PS852 25 ± 0.1
PS854 50 ± 0.1
PS851 10 ± 0.15 N-SF11a 65.6° @ 633 nm 25.76 λ/10
PS857 15 ± 0.1
PS859 20 ± 0.1
PS853 25 ± 0.1
PS855 40 ± 0.1
PS862 10 +0.0/-0.3 CaF2 31.6° @ 633 nm 95.00 λ/2
PS863 25 +0.0/-0.3
PS860 10 +0.0/-0.3 ZnSe N/A N/A λ/2
PS861 25 +0.0/-0.3
• N-SF11 stains easily. Clean off fingerprints quickly.
• The Abbe number, Vd, is calculated by: Vd= (nd - 1) / (nF - nC), where nd, nF, and nC are the indices of refraction for the helium D-line (587.6 nm), the hydrogen F-line (486.1 nm), and the hydrogen C-line (656.3 nm). A lower Abbe number indicates more dispersion.
Material Wavelength Range Index of Refraction Abbe Number
F2 385 nm - 2 µm 1.617 @ 633 nm 36.37
N-SF11 420 nm - 2.3 µm 1.779 @ 633 nm 25.76
CaF2 180 nm - 8 µm 1.433 @ 633 nm 95.00
ZnSe 600 nm - 16 µm 2.403 @ 10.6 µm N/Aa
• ZnSe is opaque at some or all visible wavelengths, and thus the Abbe number is undefined.
N-SF11 and F2
Both N-SF11 and F2 both offer excellent performance in the visible range. When compared to each other, F2, which is a flint glass, has superior chemical resistance and better transmission than N-SF11. For instance, at 420 nm the theoretical internal transmittance of a 10 mm thick piece of F2 is 0.995, whereas for the same thickness of N-SF11, the internal transmittance is 0.910. If the glass is increased to a thickness of 25 mm, these internal transmission values decrease to 0.987 and 0.790, respectively. With high indices of refraction and low Abbe Numbers Vd, both N-SF11 and F2 provide maximum dispersive power.
Calcium Fluoride
CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. The material exhibits a low refractive index, varying from 1.35 to 1.51 within its usage range of 180 nm to 8.0 µm, as well as an extremely high laser damage threshold. Calcium fluoride is also fairly chemically inert and offers superior hardness compared to its barium fluoride, magnesium fluoride, and lithium fluoride cousins.
Zine Selenide
Zinc Selenide is ideal for use in the 600 nm to 16 µm wavelength range. It features low absorption (including in the red visible wavelength range) and high resistance to thermal shock. ZnSe is ideal for use in CO2 laser systems operating at 10.6 µm, including those with HeNe alignment lasers. Please note that, due to its low hardness, care should be taken when handling ZnSe optics.
The index of refraction of various materials can be calculated via Sellmeier equations. Each material is empirically assigned a set of coefficients, through which the index of refraction can be calculated at any wavelengtha.
Sellmeier Equation 1:
Materialb K1 L1 K2 L2 K3 L3 λmina (µm) λmaxa (µm) Plot
F2 1.345 9.977 x 10-3 2.091 x 10-1 4.705 x 10-2 9.374 x 10-1 1.119 x 102 0.32 2.5
N-SF11 1.737 1.319 x 10-2 3.137 x 10-1 6.231 x 10-2 1.899 1.552 x 102 0.37 2.5
CaF2 5.676 x 10-1 2.526 x 10-3 4.711 x 10-1 1.008 x 10-2 3.848 1.201 x 103 0.23 9.7
ZnSe 4.298 3.689 x 10-2 6.278 x 10-1 1.435 x 10-1 2.896 2.208 x 103 0.55 18.0
• The Sellmeier equation is only accurate within the wavelength range specified by λmin and λmax.
• F2, N-SF11, CaF2, and ZnSe indices should be calculated using Sellmeier equation1.
### Angle of Minimum Deviation Through a Prism
If one were to use ray tracing techniques to determine the light propagation path due to the presence of the equilateral prism shown to the right, you would find that for most incidence angles, the angle of deviation of the transmitted ray (denoted by γ in the figure to the right) is roughly the same, regardless of the angle of incidence considered. However, although the angle of deviation is largely unchanged, there is a minimum value that is obtainable. This angle is known as the minimum angle of deviation; it occurs when the light ray passing through the prism is parallel to the prism's base (as shown to the right), and therefore, = β (i.e., the angle of the light ray entering the prism is identical to that of the light ray exiting the prism).
To illustrate the relationship between the incident, exit, and deviation angles in the triangle to the right, consider the equilateral triangle shown below, which is identical to the one shown to the right but has several more angles labeled. Using the geometric relationships that exist for vertical angles, it becomes apparent that A = - θ1 and C = β - θ2. Since the angles A, B, and C define a triangle, we know that A + B + C = 180o, and thus, B = 180o - (A + C) = 180o - [( - θ1) + (β - θ2)]. Finally, B + γ = 180o, so γ = 180o - B = [( - θ1) + (β - θ2)].
Now, consider the triangle outlined in green in the figure below. Here, (90 - θ1) + (90 - θ2) + 60o = 180o. Thus, θ1 + θ2 = 60o. Substituting this relationship into the end result derived in the previous paragraph, yields γ = + β - (θ1 + θ2) = + β - 60o.
For the angle of minimum deviation, = β, so there is a simple relationship between the angle of incidence and the angle of minimum deviation:
γ = + β - 60o = 2 - 60o
By applying Snell's Law to the interfaces of prism and using a little calculus, a general equation for the relationship between the index of refraction of the equilateral prism n and the angle of minimum deviation γ can be obtained:
At the design wavelength (633 nm), the indices of refraction for N-SF11 and F2 are 1.779 and 1.617, respectively. Solving for γ in the equation above yields 65.6o for N-SF11 and 47.9o for F2.
This equation can be used for prisms with n < 2.0; if the refractive index is higher, this geometry will cause total internal reflection at angle C above. ZnSe dispersive prisms, like the PS860 and PS861 prisms sold below, will have a beam exiting from the bottom face of the prism.
### Selection Guide for Prisms
Thorlabs offers a wide variety of prisms, which can be used to reflect, invert, rotate, disperse, steer, and collimate light. For prisms and substrates not listed below, please contact Tech Support.
### Beam Steering Prisms
Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Right Angle Prisms N-BK7, UV Fused Silica, Calcium Fluoride, or Zinc Selenide 90° 90° No
90° reflector used in optical systems such as telescopes and periscopes.
180° 180° No
180° reflector, independent of entrance beam angle.
Acts as a non-reversing mirror and can be used in binocular configurations.
TIR Retroreflectors
(Unmounted and Mounted)
and Specular Retroreflectors
(Unmounted and Mounted)
N-BK7 180° 180° No
180° reflector, independent of entrance beam angle.
Beam alignment and beam delivery. Substitute for mirror in applications where orientation is difficult to control.
Unmounted Penta Prisms
and
Mounted Penta Prisms
N-BK7 90° No No
90° reflector, without inversion or reversal of the beam profile.
Can be used for alignment and optical tooling.
Roof Prisms N-BK7 90° 90° 180o Rotation
90° reflector, inverted and rotated (deflected left to right and top to bottom).
Can be used for alignment and optical tooling.
Unmounted Dove Prisms
and
Mounted Dove Prisms
N-BK7 No 180° 2x Prism Rotation
Dove prisms may invert, reverse, or rotate an image based on which face the light is incident on.
Prism in a beam rotator orientation.
180° 180° No
Prism acts as a non-reversing mirror.
Same properties as a retroreflector or right angle (180° orientation) prism in an optical setup.
Wedge Prisms N-BK7 Models Available from 2° to 10° No No
Beam steering applications.
By rotating one wedged prism, light can be steered to trace the circle defined by 2 times the specified deviation angle.
No No
Variable beam steering applications.
When both wedges are rotated, the beam can be moved anywhere within the circle defined by 4 times the specified deviation angle.
Coupling Prisms Rutile (TiO2) or GGG Variablea No No
High index of refraction substrate used to couple light into films.
Rutile used for nfilm > 1.8
GGG used for nfilm < 1.8
• Depends on Angle of Incidence and Index of Refraction
### Dispersive Prisms
Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Equilateral Prisms F2, N-SF11, Calcium Fluoride,
or Zinc Selenide
Variablea No No
Dispersion prisms are a substitute for diffraction gratings.
Use to separate white light into visible spectrum.
Dispersion Compensating Prism Pairs Fused Silica, Calcium Fluoride, SF10, or N-SF14 Variable Vertical Offset No No
Compensate for pulse broadening effects in ultrafast laser systems.
Can be used as an optical filter, for wavelength tuning, or dispersion compensation.
Pellin Broca Prisms N-BK7,
UV Fused Silica,
or Calcium Fluoride
90° 90° No
Ideal for wavelength separation of a beam of light, output at 90°.
Used to separate harmonics of a laser or compensate for group velocity dispersion.
• Depends on Angle of Incidence and Index of Refraction
### Beam Manipulating Prisms
Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Anamorphic Prism Pairs N-KZFS8 or
N-SF11
Variable Vertical Offset No No
Variable magnification along one axis.
Collimating elliptical beams (e.g., laser diodes)
Converts an elliptical beam into a circular beam by magnifying or contracting the input beam in one axis.
Axicons UV Fused Silica
or Zinc Selenide
Variablea No No
Creates a conical, non-diverging beam with a Bessel intensity profile from a collimated source.
• Depends on Prism Physical Angle
### Polarization Altering Prisms
Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Glan-Taylor, Glan-Laser, and α-BBO Glan-Laser Polarizers Glan-Taylor:
Calcite
Glan-Laser:
α-BBO or Calcite
p-pol. - 0°
s-pol. - 112°a
No No
Double prism configuration and birefringent calcite produce extremely pure linearly polarized light.
Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Rutile Polarizers Rutile (TiO2) s-pol. - 0°
p-pol. absorbed by housing
No No
Double prism configuration and birefringent rutile (TiO2) produce extremely pure linearly polarized light.
Total Internal Reflection of p-pol. at the gap between the prisms while s-pol. is transmitted.
Double Glan-Taylor Polarizers Calcite p-pol. - 0°
s-pol. absorbed by housing
No No
Triple prism configuration and birefringent calcite produce maximum polarized field over a large half angle.
Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Glan Thompson Polarizers Calcite p-pol. - 0°
s-pol. absorbed by housing
No No
Double prism configuration and birefringent calcite produce a polarizer with the widest field of view while maintaining a high extinction ratio.
Total Internal Reflection of s-pol. at the gap between the prism while p-pol. is transmitted.
Wollaston Prisms and
Wollaston Polarizers
Quartz, Magnesium Fluoride, α-BBO, Calcite, Yttrium Orthovanadate Symmetric
p-pol. and
s-pol. deviation angle
No No
Double prism configuration and birefringent calcite produce the widest deviation angle of beam displacing polarizers.
s-pol. and p-pol. deviate symmetrically from the prism. Wollaston prisms are used in spectrometers and polarization analyzers.
Rochon Prisms Magnesium Fluoride
or
Ordinary Ray: 0°
Extraordinary Ray: deviation angle
No No
Double prism configuration and birefringent MgF2 or YVO4 produce a small deviation angle with a high extinction ratio.
Extraordinary ray deviates from the input beam's optical axis, while ordinary ray does not deviate.
Beam Displacing Prisms Calcite 2.7 or 4.0 mm Beam Displacement No No
Single prism configuration and birefringent calcite separate an input beam into two orthogonally polarized output beams.
s-pol. and p-pol. are displaced by 2.7 or 4.0 mm. Beam displacing prisms can be used as polarizing beamsplitters where 90o separation is not possible.
Fresnel Rhomb Retarders N-BK7 Linear to circular polarization
Vertical Offset
No No
λ/4 Fresnel Rhomb Retarder turns a linear input into circularly polarized output.
Uniform λ/4 retardance over a wider wavelength range compared to birefringent wave plates.
Rotates linearly polarized light 90° No No
λ/2 Fresnel Rhomb Retarder rotates linearly polarized light 90°.
Uniform λ/2 retardance over a wider wavelength range compared to birefringent wave plates.
• S-polarized light is not pure and contains some P-polarized reflections.
### Beamsplitter Prisms
Prism Material Deviation Invert Reverse or Rotate Illustration Applications
Beamsplitter Cubes N-BK7 50:50 splitting ratio, 0° and 90°
s- and p- pol. within 10% of each other
No No
Double prism configuration and dielectric coating provide 50:50 beamsplitting nearly independent of polarization.
Non-polarizing beamsplitter over the specified wavelength range.
Polarizing Beamsplitter Cubes N-BK7, UV Fused Silica, or N-SF1 p-pol. - 0°
s-pol. - 90°
No No
Double prism configuration and dielectric coating transmit p-pol. light and reflect s-pol. light.
For highest polarization use the transmitted beam.
## F2 Equilateral Dispersive Prisms (385 nm - 2 µm)
Click to Enlarge
Transmission data is for a 10 mm thick sample.
F2 is a flint glass that offers excellent performance in the visible and NIR spectral range. It offers a high refractive index and low Abbe number, making it excellent for use in an equilateral dispersive prism. Compared to N-SF11, it offers superior chemical resistance and slightly higher transmission.
Polarization Effects
For p-polarized light (blue line) incident on a dispersing prism at the angle of least deviation, the graph to the right shows that only a small percentage of the p-polarized light is reflected at the surface. Thus, for this polarization, the transmission through a prism fabricated from F2 will be excellent even though there is no AR coating on the surface.
Material Minimum Angle
of Deviation
Vdb Surface Flatness
@ 633 nm
Clear
Aperture
Surface
Quality
Angular
Tolerance
Number of
Polished Faces
Index of
Refraction Plot
F2a 47.9° @ 633 nm 36.37 λ/10 70% 40-20 Scratch-Dig ±5 arcmin 2c
• Click Link for Detailed Specifications on the Substrate Glass
• The Abbe number, Vd, is calculated by: Vd= (nd - 1) / (nF - nC), where nd, nF, and nC are the indices of refraction for the helium D-line (587.6 nm), the hydrogen F-line (486.1 nm), and the hydrogen C-line (656.3 nm). A lower Abbe number indicates more dispersion.
• One face and the bases are fine ground.
Based on your currency / country selection, your order will ship from Newton, New Jersey
+1 Qty Docs Part Number - Universal Price Available
PS850 F2 Equilateral Dispersive Prism, 10 mm
$93.61 Today PS856 F2 Equilateral Dispersive Prism, 15 mm$100.91
Today
PS858 F2 Equilateral Dispersive Prism, 20 mm
$108.21 Today PS852 F2 Equilateral Dispersive Prism, 25 mm$121.20
Today
PS854 F2 Equilateral Dispersive Prism, 50 mm
$244.56 Today ## N-SF11 Equilateral Dispersive Prisms (420 nm - 2.3 µm) Click to Enlarge Download an Excel File with Raw Transmission Data Transmission data is for a 10 mm thick sample. N-SF11 is a flint glass that offers excellent performance in the visible and NIR spectral range. It offers a high refractive index and low Abbe number, making it excellent for use in an equilateral dispersive prism. Polarization Effects For P-Polarized light (blue line) incident on a dispersing prism at the angle of least deviation, the graph to the right shows that only a small percentage of the p-polarized light is reflected at the surface. Thus, for this polarization, the transmission through a prism fabricated from N-SF11, a RoHS-compliant version of SF11, will be excellent even though there is no AR coating on the surface. Material Minimum Angle of Deviation Vdb Surface Flatness @ 633 nm Clear Aperture Surface Quality Angular Tolerance Number of Polished Faces Index of Refraction Plot N-SF11a 65.5° @ 633 nm 24.76 λ/10 70% 40-20 Scratch-Dig ±5 arcmin 2c • N-SF11 stains easily. Clean off fingerprints quickly. Click the link for detailed specifications on the substrate glass. • The Abbe number, Vd, is calculated by: Vd= (nd - 1) / (nF - nC), where nd, nF, and nC are the indices of refraction for the helium D-line (587.6 nm), the hydrogen F-line (486.1 nm), and the hydrogen C-line (656.3 nm). A lower Abbe number indicates more dispersion. • One face and the bases are fine ground. Based on your currency / country selection, your order will ship from Newton, New Jersey +1 Qty Docs Part Number - Universal Price Available PS851 N-SF11 Equilateral Dispersive Prism, 10 mm$85.49
Today
PS857 N-SF11 Equilateral Dispersive Prism, 15 mm
$85.49 Today PS859 N-SF11 Equilateral Dispersive Prism, 20 mm$91.18
Today
PS853 N-SF11 Equilateral Dispersive Prism, 25 mm
$91.18 Today PS855 N-SF11 Equilateral Dispersive Prism, 40 mm$222.91
Today
## CaF2 Equilateral Dispersive Prisms (180 nm - 8 µm)
CaF2 is commonly used for applications requiring high transmission in the infrared and ultraviolet spectral ranges. The material exhibits a low refractive index, varying from 1.35 to 1.51 within its usage range of 180 nm to 8.0 µm, as well as an extremely high laser damage threshold. Calcium fluoride is also fairly chemically inert and offers superior hardness compared to its barium fluoride, magnesium fluoride, and lithium fluoride cousins.
Material Minimum Angle
of Deviation
Vdb Surface Flatness
@ 633 nm
Clear
Aperture
Surface
Quality
Angular
Tolerance
Number of
Polished Faces
Index of
Refraction Plot
CaF2a 31.6° @ 633 nm 95.00 λ/2 70% 40-20 Scratch-Dig ±3 arcmin 2c
• Click Link for Detailed Specifications on the Substrate Glass
• The Abbe number, Vd, is calculated by: Vd= (nd - 1) / (nF - nC), where nd, nF, and nC are the indices of refraction for the helium D-line (587.6 nm), the hydrogen F-line (486.1 nm), and the hydrogen C-line (656.3 nm). A lower Abbe number indicates more dispersion.
• One face and the bases are fine ground.
Based on your currency / country selection, your order will ship from Newton, New Jersey
+1 Qty Docs Part Number - Universal Price Available
PS862 CaF2 Equilateral Dispersive Prism, Uncoated, 10 mm
$354.94 Today PS863 CaF2 Equilateral Dispersive Prism, Uncoated, 25 mm$551.88
Today
## ZnSe Equilateral Dispersive Prisms (600 nm - 16 µm)
Zinc Selenide is ideal for use in the 600 nm 16 µm range. It features low absorption (including in the red visible wavelength range) and high resistance to thermal shock. ZnSe is ideal for use in CO2 laser systems operating at 10.6 µm, including those with HeNe alignment lasers. Note that due to their high refractive index, these prisms can not be used in the traditional orienation described in the Equilateral Tutorial tab above.
When handling optics, one should always wear gloves. This is especially true when working with zinc selenide, as it is a hazardous material. For your safety, please follow all proper precautions, including wearing gloves when handling these prisms and thoroughly washing your hands afterward. Due to the low hardness of ZnSe, additional care should be taken to not damage these prisms. Click here to download a pdf of the MSDS for ZnSe.
Thorlabs will accept all ZnSe prisms back for proper disposal. Please contact Tech Support to make arrangements for this service.
Material Surface Flatness
@ 633 nm
Clear
Aperture
Surface Quality Angular Tolerance Number of Polished Faces Index of
Refraction Plot
ZnSea λ/2 70% 60-40 Scratch-Dig ±10 arcmin 3b
• Click Link for Detailed Specifications on the Substrate Glass
• The bases are fine ground.
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PS860 ZnSe Equilateral Dispersive Prism, Uncoated, 10 mm
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https://math.stackexchange.com/questions/1738696/probability-of-picking-frac13-between-the-interval-0-1/1738707
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# probability of picking $\frac{1}{3}$ between the interval $[0,1]$?
My professor told us a situation in class which i do not understand very well.
He said "what is the probability of picking $\frac{1}{3}$ between the interval $[0,1]$?" and then he proved it to be $0$. He said something like if you continue to pick subsets of $\frac{1}{3}$ it will eventually branch off to $0$.
I wanted to ask my professor to clarify but he had a meeting afterwards. Therefore, I come to you all. Does anyone think they can explain this concept to me?
• There are infinite possible numbers (between 0 and 1) which can be picked. Thus the probability of picking a specific number is zero. – callculus Apr 12 '16 at 5:28
• If your professor means for the probability distribution over $[0,1]$ to be uniform, then he is correct that the probability of getting exactly $\frac{1}{3}$ is zero. One way to explain why this is the case is that measure of the set $\{ \frac{1}{3}\}$ is zero in this case. – Justin Benfield Apr 12 '16 at 5:28
• Roughly speaking, there are infinitely many points in $[0,1]$ and $\frac 13$ is just one of them, so the probability of picking it is $\frac 1{\infty}$. – BigbearZzz Apr 12 '16 at 5:28
• @JustinBenfield, i think my professor was using your idea – yaniz rakiov Apr 12 '16 at 5:30
$1/3$ lies in the interval $[0,1/2]$, and there is probability $1/2$ of any point we choose in $[0,1]$ lying in that interval. Further, $1/3$ lies in $[1/4,1/2]$, and there is probability $1/4$ of any point we choose in $[0,1]$ lying in this interval. Likewise, $1/3$ lies in $[1/4,3/8]$, which we would land in with probability $1/8$. Continue in this manner inductively constructing a sequence of nested intervals of length $1/2^n$, each containing the point $1/3$.
This means that the probability of choosing $1/3$ out of the interval $[0,1]$ is smaller than the length of any of these nested intervals that contain the point $1/3$, and hence the probability is smaller than $1/2^n$ for any positive integer $n$, so the probability must be $0$.
I will answer this question by asking you How many number are there in the interval $$[0,1]$$ and remember it is a continuous realnumber line
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https://stacks.math.columbia.edu/tag/02KO
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Definition 35.19.1. Let $\mathcal{P}$ be a property of morphisms of schemes over a base. Let $\tau \in \{ fpqc, fppf, syntomic, smooth, {\acute{e}tale}, Zariski\}$. We say $\mathcal{P}$ is $\tau$ local on the base, or $\tau$ local on the target, or local on the base for the $\tau$-topology if for any $\tau$-covering $\{ Y_ i \to Y\} _{i \in I}$ (see Topologies, Section 34.2) and any morphism of schemes $f : X \to Y$ over $S$ we have
$f \text{ has }\mathcal{P} \Leftrightarrow \text{each }Y_ i \times _ Y X \to Y_ i\text{ has }\mathcal{P}.$
In your comment you can use Markdown and LaTeX style mathematics (enclose it like $\pi$). A preview option is available if you wish to see how it works out (just click on the eye in the toolbar).
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https://www.snapxam.com/problems/42617908/16-1x-2-10-1x
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# Solve the quadratic equation $16-x^2=10-x$
## Step-by-step Solution
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### Videos
$x=-3,\:x=2$
Got another answer? Verify it here!
## Step-by-step Solution
Problem to solve:
$16-x^2=10-x$
Specify the solving method
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Group the terms of the equation by moving the terms that have the variable $x$ to the left side, and those that do not have it to the right side
$-x^2+x=-6$
Learn how to solve quadratic equations problems step by step online.
$-x^2+x=-6$
Learn how to solve quadratic equations problems step by step online. Solve the quadratic equation 16-x^2=10-x. Group the terms of the equation by moving the terms that have the variable x to the left side, and those that do not have it to the right side. Rewrite the equation. Factor the trinomial by -1 for an easier handling. Factor the trinomial -\left(x^2+x-6\right) finding two numbers that multiply to form -6 and added form -1.
$x=-3,\:x=2$
SnapXam A2
### beta Got another answer? Verify it!
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$16-x^2=10-x$
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https://www.lmfdb.org/GaloisGroup/?n=30
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Results (displaying matches 1-50 of at least 5000) Next
Label Name Order Parity Solvable Subfields Low Degree Siblings
30T1 $C_{30}$ 30 -1 Yes $C_2$, $C_3$, $C_5$, $C_6$, $C_{10}$, $C_{15}$
30T2 $C_5\times S_3$ 30 -1 Yes $C_2$, $S_3$, $C_5$, $S_3$, $C_{10}$, $S_3 \times C_5$ 15T4
30T3 $D_{15}$ 30 -1 Yes $C_2$, $S_3$, $D_{5}$, $S_3$, $D_5$, $D_{15}$ 15T2
30T4 $C_3\times D_5$ 30 -1 Yes $C_2$, $C_3$, $D_{5}$, $C_6$, $D_5$, $D_5\times C_3$ 15T3
30T5 $C_6\times D_5$ 60 -1 Yes $C_2$, $C_3$, $D_{5}$, $C_6$, $D_{10}$, $D_5\times C_3$ 30T5
30T6 $C_3:F_5$ 60 -1 Yes $C_2$, $S_3$, $F_5$, $S_3$, $F_5$, $C_{15} : C_4$ 15T6
30T7 $C_3\times F_5$ 60 -1 Yes $C_2$, $C_3$, $F_5$, $C_6$, $F_5$, $F_5\times C_3$ 15T8
30T8 $S_3\times D_5$ 60 -1 Yes $C_2$, $S_3$, $D_{5}$, $S_3$, $D_{10}$, $D_5\times S_3$ 15T7, 30T10, 30T13
30T9 $A_5$ 60 1 No $A_5$, $\PSL(2,5)$, $A_{5}$, $A_5$ 5T4, 6T12, 10T7, 12T33, 15T5, 20T15
30T10 $S_3\times D_5$ 60 -1 Yes $C_2$, $S_3$, $D_{5}$, $D_{6}$, $D_5$, $D_5\times S_3$ 15T7, 30T8, 30T13
30T11 $C_5\times A_4$ 60 1 Yes $C_3$, $C_5$, $A_4$, $C_{15}$ 20T14
30T12 $C_{10}\times S_3$ 60 -1 Yes $C_2$, $S_3$, $C_5$, $D_{6}$, $C_{10}$, $S_3 \times C_5$ 30T12
30T13 $S_3\times D_5$ 60 -1 Yes $C_2$, $S_3$, $D_{5}$, $D_{6}$, $D_{10}$, $D_5\times S_3$ 15T7, 30T8, 30T10
30T14 $D_{30}$ 60 -1 Yes $C_2$, $S_3$, $D_{5}$, $D_{6}$, $D_{10}$, $D_{15}$ 30T14
30T15 $C_{15}\times S_3$ 90 -1 Yes $C_2$, $C_5$, $S_3\times C_3$, $C_{10}$ 45T3
30T16 $C_3\times D_{15}$ 90 -1 Yes $C_2$, $D_{5}$, $S_3\times C_3$, $D_5$ 45T5
30T17 $C_2\times C_3:F_5$ 120 -1 Yes $C_2$, $S_3$, $F_5$, $D_{6}$, $F_{5}\times C_2$, $C_{15} : C_4$ 30T17
30T18 $C_{10}\times A_4$ 120 -1 Yes $C_3$, $C_5$, $A_4\times C_2$, $C_{15}$ 40T59
30T19 $C_5:S_4$ 120 1 Yes $S_3$, $D_{5}$, $S_4$, $D_{15}$ 20T33, 30T31, 40T63
30T20 $D_5\times A_4$ 120 -1 Yes $C_3$, $D_{5}$, $A_4\times C_2$, $D_5\times C_3$ 20T37, 30T28, 40T65
30T21 $C_2\times S_3\times D_5$ 120 -1 Yes $C_2$, $S_3$, $D_{5}$, $D_{6}$, $D_{10}$, $D_5\times S_3$ 30T21 x 3
30T22 $S_5$ 120 -1 No $S_5$, $\PGL(2,5)$, $S_5$ 5T5, 6T14, 10T12, 10T13, 12T74, 15T10, 20T30, 20T32, 20T35, 24T202, 30T25, 30T27, 40T62
30T23 $S_3\times F_5$ 120 -1 Yes $C_2$, $S_3$, $F_5$, $D_{6}$, $F_{5}\times C_2$, $F_5 \times S_3$ 15T11, 30T24, 30T32
30T24 $S_3\times F_5$ 120 -1 Yes $C_2$, $S_3$, $F_5$, $D_{6}$, $F_5$, $F_5 \times S_3$ 15T11, 30T23, 30T32
30T25 $S_5$ 120 -1 No $C_2$, $S_5$, $S_5$, $S_5$ 5T5, 6T14, 10T12, 10T13, 12T74, 15T10, 20T30, 20T32, 20T35, 24T202, 30T22, 30T27, 40T62
30T26 $C_6\times F_5$ 120 -1 Yes $C_2$, $C_3$, $F_5$, $C_6$, $F_{5}\times C_2$, $F_5\times C_3$ 30T26
30T27 $S_5$ 120 1 No $S_5$, $S_5$, $S_5$ 5T5, 6T14, 10T12, 10T13, 12T74, 15T10, 20T30, 20T32, 20T35, 24T202, 30T22, 30T25, 40T62
30T28 $D_5\times A_4$ 120 1 Yes $C_3$, $D_{5}$, $A_4$, $D_5\times C_3$ 20T37, 30T20, 40T65
30T29 $C_2\times A_5$ 120 -1 No $A_5$, $A_5$ 10T11, 12T75, 12T76, 20T31, 20T36, 24T203, 30T30, 40T61
30T30 $C_2\times A_5$ 120 -1 No $C_2$, $A_5$, $A_5\times C_2$, $A_5$ 10T11, 12T75, 12T76, 20T31, 20T36, 24T203, 30T29, 40T61
30T31 $C_5:S_4$ 120 -1 Yes $S_3$, $D_{5}$, $S_4$, $D_{15}$ 20T33, 30T19, 40T63
30T32 $S_3\times F_5$ 120 -1 Yes $C_2$, $S_3$, $F_5$, $S_3$, $F_{5}\times C_2$, $F_5 \times S_3$ 15T11, 30T23, 30T24
30T33 $C_5\times S_4$ 120 1 Yes $S_3$, $C_5$, $S_4$, $S_3 \times C_5$ 20T34, 30T34, 40T64
30T34 $C_5\times S_4$ 120 -1 Yes $S_3$, $C_5$, $S_4$, $S_3 \times C_5$ 20T34, 30T33, 40T64
30T35 $C_5^2:C_6$ 150 -1 Yes $C_2$, $C_3$, $C_6$, $(C_5^2 : C_3):C_2$ 15T12 x 2, 25T15, 30T35
30T36 $C_5\times D_{15}$ 150 -1 Yes $C_2$, $S_3$, $S_3$, $D_5\times C_5$ 30T36
30T37 $C_5^2:S_3$ 150 -1 Yes $C_2$, $S_3$, $S_3$, $(C_5^2 : C_3):C_2$ 15T13, 15T14, 25T16, 30T38
30T38 $C_5^2:S_3$ 150 -1 Yes $C_2$, $S_3$, $S_3$, $(C_5^2 : C_3):C_2$ 15T13, 15T14, 25T16, 30T37
30T39 $C_{15}\times D_5$ 150 -1 Yes $C_2$, $C_3$, $C_6$, $D_5\times C_5$ 30T39
30T40 $C_2\times C_5^2:C_3$ 150 -1 Yes $C_2$, $C_3$, $C_6$, $C_5^2 : C_3$ 30T40
30T41 $C_5\times S_3^2$ 180 -1 Yes $C_2$, $C_5$, $S_3^2$, $C_{10}$ 45T15
30T42 $S_3\times D_{15}$ 180 -1 Yes $C_2$, $D_{5}$, $S_3^2$, $D_{10}$ 45T13
30T43 $D_{15}:S_3$ 180 -1 Yes $C_2$, $D_{5}$, $S_3^2$, $D_5$ 45T21
30T44 $C_3\times S_3\times D_5$ 180 -1 Yes $C_2$, $D_{5}$, $S_3\times C_3$, $D_{10}$ 45T14
30T45 $C_3\times A_5$ 180 1 No $C_3$, $A_{5}$ 15T15 x 2, 15T16, 18T90, 36T176, 45T16
30T46 $(C_3\times C_{15}):C_4$ 180 1 Yes $C_2$, $F_5$, $C_3^2:C_4$, $F_5$ 30T46, 45T27
30T47 $C_3\times C_3:F_5$ 180 -1 Yes $C_2$, $F_5$, $S_3\times C_3$, $F_5$ 45T18
30T48 $C_3^2:(C_5:C_4)$ 180 1 Yes $C_2$, $D_{5}$, $C_3^2:C_4$, $D_5$ 30T48, 45T26
30T49 $C_5\times C_3:S_3.C_2$ 180 1 Yes $C_2$, $C_5$, $C_3^2:C_4$, $C_{10}$ 30T49, 45T25
30T50 $F_{16}$ 240 1 Yes $C_3$, $C_5$, $C_{15}$ 16T447, 20T67
Next
Results are complete for degrees $\leq 23$.
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https://simple.wikipedia.org/wiki/Zeroth_law_of_thermodynamics
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# Zeroth law of thermodynamics
The Zeroth Law of Thermodynamics says that if a change to the temperature(T) from one object (for example 'A') changes the temperature of another object ('B'), and a change to the temperature of 'B' changes the temperature of 'C' (a third object), then a change to the temperature of 'A' will mean a change to the temperature of 'C'. Heat naturally flows from areas that are hot to areas that are cold.
More simply:
${\displaystyle \mathrm {if} ~T(A)=T(B)}$
${\displaystyle \mathrm {if} ~T(B)=T(C)}$
${\displaystyle \mathrm {then} ~T(A)=T(C)}$
It is called the zeroth (0th) law of thermodynamics because it was discovered after the others, but scholars thought it was more important so they wanted to give it a number before the other laws.
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https://sbseminar.wordpress.com/2007/09/28/typesetting-question/
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# Typesetting Question
Stephen Hawking’s publisher told him that, for every equation Hawking included, his readership would drop in half. I think it is fair to say that readers of the Secret Blogging Seminar are made of sterner stuff! However, including LaTeX objects in blog posts is a burden on the reader because (1) they are displayed as images and hence take longer to load (2) they can’t be cut and pasted, reducing the usefulness of the post and (3) on many browsers (particularly Safari) they can cause problems with text alignment. For this reason, I have tried to use fewer LaTeX objects writing here than I do when writing works meant to be read as PDF’s.
What I am wondering is whether or not to use LaTeX objects to display symbols that can be represented with ordinary characters. For example, which of the following is best?
We denote by $\lfloor a \rfloor$ the greatest integer less than or equal to $a$.
We denote by $\lfloor a \rfloor$ the greatest integer less than or equal to a.
We denote by $\lfloor a \rfloor$ the greatest integer less than or equal to a.
(If you can’t tell, the “a” on the second line is italicized, using the HTML tag “<i>”.)
## 28 thoughts on “Typesetting Question”
1. Richard says:
For example, Safari does not correctly display Tao’s What’s New blog. Instead of accommodating Safari with work arounds, we should be complaining to Apple that the browser is not working correctly. I use the OmniWeb browser on my Mac and it does not seem to have any problems with this.
2. Michael Kinyon says:
The first one is best. Switching from the one-story math $\latex a$ to the other type looks weird. Personally, I don’t find the problems you list to be significant enough to take pains to avoid LaTeX. At least, that’s going to be how I handle my own research blog, once I get it up and running.
3. Michael Kinyon says:
Oops! That should have been $a$. I hope it comes out this time.
4. I’d prefer the first of the three. In my browser, in the second and third versions, the variable name looks totally different in the floor than it does on its own: the one inside the floor has a large loop with a tail on the right, while the other one has a small loop with a bigger tail above it. Consistency of formatting is important because otherwise it might seem that you’re deliberately using two different types of a to mean two different things.
5. Kinda sad that you have to even think about whether to type some math, let alone poll your readers about it.
Despite the fact that I think using pictures of equations is evil (for the reasons you cite and for a bunch of others), there is one point on which you are too pessimistic.
Copy/paste is no worse with pictures than it currently is with MathML.
In Gecko-based browsers, highlight the text you want to copy, bring up the context menu (right-click), and choose “View Selection Source”. Copy that, and paste it at will
We denote by the greatest integer less than or equal to .
We denote by the greatest integer less than or equal to a.
We denote by the greatest integer less than or equal to a.
Let’s see how that worked, shall we?
6. Ah.
I see. It doesn’t work because WordPress removes &img /& tags from your comments.
Yep. I guess that is broken …
7. Not the third. The first is great — download time is minimal, especially for little pdfs — and I don’t mind the second, although the “a”s do look different.
How about doing everything in MathML instead?
8. Richard, I highly disagree. Safari is not rendering the page incorrectly. What it is doing is trying to render as much of the page as soon as possible, as opposed to other browsers which download the entire page first and then render the whole page.
9. What you might consider doing is providing a pdf version of a post. Then those who have browser problems could just download the pdf.
You can create a sed script that converts wordpress markup to LaTeX (replaces $foo$ with $foo$, html i tag with \em{} etc.). As long as you do not use complicated formatting (tables, …) this is quite feasible.
10. Scott Carnahan says:
If Safari does not reflow the text when it discovers the image sizes, then that is a bug. If this is the only problem, wordpress could work around it by including the sizes of the images in the img tags.
In my experience, Safari gives me a beach ball when rendering a wordpress page with a lot of math, and it takes a few seconds for the UI to be responsive again. I’d prefer if it took a little longer but remained somewhat responsive (assuming such a trade-off is even necessary).
11. I have not had problems with WordPress math on Safari since switching to version 3 (3.0.3, I guess). Safari still doesn’t seem to get along with the WordPress live editor, though.
12. It tries to reflow the text, but when you’ve got so many inline like that it sometimes loses track. Frankly, it’s never bothered me that much.
On the other hand, I’ve never gotten the beach ball, so maybe something’s different on your system than mine.
13. I also prefer the first of the three. With Firefox on a linuxbox, everything displays correctly.
14. carlbrannen says:
Everyone prefers the first, but the third gets the point across perfectly and is much faster to type and load. I vote for using it. And I have noticed that a lot of your pages take ages to load.
Let’s put it this way. Which does the audience prefer? Fewer posts written the first way, or more posts written the third?
15. David Speyer says:
I think that, once I get used to wordpress, the first will hardly take any longer to write. I am already used to using LaTeX enough that I will often enclose mathematical symbols in $’s in an e-mail without thinking about it. I haven’t gotten used to typing “$ latex” yet, but I assume that I will.
I am surprised that no one cares about the time to load, though. I know that, when I am using a busy wireless conection and I look at one of the longer posts on this blog or Tao’s blog, there is often a noticeable lag time. This is made more annoying because I have to refresh to deal with the above mentioned Safari bug. Judging from the comments though, this doesn’t bother many people.
16. Aaron Bergman says:
As a contrary opinion, I think (2) is vastly preferable. (1) is ugly.
17. I actually would vote for 2 or 3. The load time just isn’t worth it. I admit, I’m using Safari which is part of it. But I have found that with Safari if you just reload the page then the second time it usually displays everything correctly.
18. The difference in font for the “a” in lines 2 and 3 is kind of jarring — if not for that, line 2 would fine. Of course in your example, you could actually do the whole thing just using HTML entities, and avoid the font mismatch:
We denote by ⌊a⌋ the greatest integer less than or equal to a.
(Hopefully the comment editor does the right thing with that.) Philosophically, I feel strongly that MathML is the right way to deal with this problem, although pragmatically it looks like using images rendered from LaTeX is the way people are going. I find it disheartening that the only way I can seem to get MathML and SVG images to display simultaneously is using IE with separate plug-ins for MathML and SVG, but the hopefully next generation of browsers will make this whole issue of historical interest only.
19. David, I assure you you’ll get used to it. I just keep “$latex” in my clipboard (Command-C) at all times, just to be ready to paste it over and over again without even thinking. 20. Dima says: what about plain Unicode:⎣a⎦? (I know, it looks less than beautiful, but it loads faster than images, that’s for sure… 21. Kurt wrote: Philosophically, I feel strongly that MathML is the right way to deal with this problem, although pragmatically it looks like using images rendered from LaTeX is the way people are going. It’s just not feasible to use MathML in WordPress or, for that matter, in most hosted blogging services (Blogger, WordPress.com, Typepad, …). I find it disheartening that the only way I can seem to get MathML and SVG images to display simultaneously is using IE with separate plug-ins for MathML and SVG, but the hopefully next generation of browsers will make this whole issue of historical interest only. Browsers in the Mozilla family (Seamonkey, Firefox and Camino) support both natively. 22. Jacques wrote: It’s just not feasible to use MathML in WordPress or, for that matter, in most hosted blogging services (Blogger, WordPress.com, Typepad, …). Is this because it’s too tedious to compose using the editors provided with those platforms? Or are the host servers not handling the MathML properly for some reason? Browsers in the Mozilla family (Seamonkey, Firefox and Camino) support both natively. I guess I’m a little bit out of date here. I could never get SVG to work to my satisfaction with Firefox 1.5, but I haven’t tried it out since switching to 2.0. I suppose this also raises the question of how to best serve one’s readers–especially for people who may be reading a blog from work and not have a choice of which browser or plug-ins to use. Every browser will support inline images, but the other stuff is still kind of hit-or-miss. 23. Is this because it’s too tedious to compose using the editors provided with those platforms? Or are the host servers not handling the MathML properly for some reason? Composition is the “easy” part. You use a plugin that converts (a subset of) LaTeX to MathML. I even wrote one for WordPress. The hard part is that MathML and inline SVG must be embedded in an XHTML web page, which must be served as application/xhtml+xml (“real” XHTML), instead of text/html. Which means that your pages need to adhere to the strict well-formedness requirements of XML. It’s easy to get WordPress to spit out the desired content-type. Unfortunately, getting WordPress to reliably produce well-formed XHTML is pretty close to impossible. Most people who’ve tried have given up in frustration. MovableType is only a little better (but, clearly, possible). When SixApart releases their open-source version of MT (very soon, I hope), I’ll have to see about rolling a variant which, out of the box, does MathML. Looking beyond blogging software, I’m pretty pleased with the MathML/SVG support in Instiki. I guess I’m a little bit out of date here. I could never get SVG to work to my satisfaction with Firefox 1.5, but I haven’t tried it out since switching to 2.0. You are a bit out of date. Not only Firefox, but also Safari (3.0beta) and Opera have quite good native support for SVG. I suppose this also raises the question of how to best serve one’s readers–especially for people who may be reading a blog from work and not have a choice of which browser or plug-ins to use. Every browser will support inline images, but the other stuff is still kind of hit-or-miss. If you’re working in some setting where reading mathematical content on the Web might reasonably be considered a job-related activity, then demanding a browser upgrade (or plugin installation) would be perfectly justified. 24. First off, I’m using MathML with some success in a wordpress installation – albeit NOT, should be said, in one by a hosting site somewhere. Furthermore, one of the ideas I have been bouncing around the DMV lately has been to setup a site specifically catered to mathematics bloggers – with MathML integrated from the get go, and with everything tuned and managed to keep mathematics writing as easy as possible. So far, I simply haven’t had time to put into the project, but on the noises I’ve heard, getting hardware to set something like this up wouldn’t be hard, and neither would getting a decent domain name to back it up, and automation for constructing new blogs. 25. >First off, I’m using MathML with some success in a wordpress installation – albeit NOT, should be said, in one by a hosting site somewhere. Really? Cool! Is this on a publicly-accessible blog somewhere? (blog.mikael.johanssons.org, obviously, isn’t the one you’re talking about.) Have you released the WordPress patches/plugins required to pull it off. Furthermore, one of the ideas I have been bouncing around the DMV lately has been to setup a site specifically catered to mathematics bloggers – with MathML integrated from the get go, and with everything tuned and managed to keep mathematics writing as easy as possible. Well, at least as far as the software goes, that’s my plan for MTOS. The thing I’m still debating is whether to try to stay as close to a “stock” version of MT, adding only those things necessary to get MathML working, or to produce something with all the bells and whistles you’d find at my blog or at the n-Category Café. 26. carlbrannen says: Perhaps illustrating the difference in how physicists and mathematicians treat details like typesetting and grammar, a QFT textbook I bought over the weekend includes the memorable phrase “without loosing generality.” 27. Carl, I suggest you pick yourself up a copy of Gelfand and Manin’s “Homological Algebra” before making jokes about the proofreading behaviour of physicists. 28. t8m8r says: Dmitry, can you elaborate on the sed script a bit more? I was thinking about writing a command line tool or a Java program that converts LaTeX documents to WordPress format, transforming to$latex, \emph{} to and so on. But then things get complicated if you have used, for example \begin{split} or \begin{eqnarray} etc.
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https://operativeneurosurgery.com/doku.php?id=atmospheric_pressure
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# Operative Neurosurgery
### Site Tools
atmospheric_pressure
## Atmospheric pressure
Atmospheric pressure, sometimes also called barometric pressure, is the pressure exerted by the weight of air in the atmosphere of Earth (or that of another planet). In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Low-pressure areas have less atmospheric mass above their location, whereas high-pressure areas have more atmospheric mass above their location. Likewise, as elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. On average, a column of air one square centimeter in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kg and weight of about 10.1 N (2.27 lbf) That force over one square centimeter is a pressure of 10.1 N/cm2 or 101000 N/m2. (A column one square inch in cross-section would have a weight of about 14.7 lb, or about 65.4 N.).
The cranial cavity is a closed compartment and any breach to this confined space secondary to neurosurgery or trauma cause an imbalance between atmospheric pressure and intracranial pressure. As the altitude increases, the atmospheric pressure decreases and hypoxia with hypercarbia is a well-known fact. In children, there is an argument to suggest that hypoxia can contribute to mild increase in intracranial pressure during commercial flights 1).
Fodstad et al. also commented on the effect of atmospheric pressure acting directly on cerebral tissue during craniectomy. According to them, during an upright position intracranial pressure would equalize with the atmospheric pressure 2).
1)
Lo Presti A, Weil AG, Ragheb J. Flying with a shunt. J Neurosurg Pediatr. 2015;15(2):223-224.
2)
Fodstad H, Love JA, Ekstedt J, Fridén H, Liliequist B. Effect of cranioplasty on cerebrospinal fluid hydrodynamics in patients with the syndrome of the trephined. Acta Neurochir (Wien). 1984;70(1-2):21-30. PubMed PMID: 6741628.
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https://neuraloutlet.wordpress.com/tag/mathematics/
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# Mandelbrot: SETL & Lisp
SETL is a general-purpose programming language developed by Jack Schwartz back in the late 1960s. The language is multiparadigm – both Procedural (containing subroutines and control structures like if statements) and Set Theoretical. The latter is not often mentioned when talking about language paradigms – and is not to be confused with Logical Programming. The concept is outlined in the 1974 paper An Introduction to the Set Theoretical Language SETL. Importantly though data in SETL is of three main types: Atoms, Sets, and Sequences (also referred to as tuples or ordered sets).
A good overview of SETL can be found in the GNU SETL Om.
Pixels inside the Mandelbrot Set are marked in black, the code used to generate them (mandelbrot.setl) can be found here.
Generation of the Mandelbrot Set
On the Wikipedia page for the Mandelbrot Set you will find its formal definition, which looks like so: $M = \left\{c\in \mathbb C : \exists s\in \mathbb R, \forall n\in \mathbb N, |P_c^n(0)| \le s \right\}.$
The most fantastic thing about SETL is how powerful its Set Builder Notation is. Almost exactly as you would in the formal case (removing ‘there exists some real s’ for the practical application):
M := {c : c in image | forall num in {0..iterations} | cabs(pofc(c, num)) <= 2};
For some reason SETL doesn’t support complex numbers, but they are easily handled by writing the necessary procedures we need like cabs, ctimes, and cplus dealing with tuples in the form [x, y]. The variable ‘image’ is a sequence of these tuples. Another procedure is written, pofc, which is a more practical version of $P_c^n(0)$.
Interaction with the Lisp graphical display
The goal of the SETL program is to produce a set of points that lie inside the Mandelbrot set. To actually display the image I used Common Lisp and displayed a widget with the image using CommonQt. In a very rudimentary way I had mandelbrot.setl take arguments about the image then print the set of pixel co-ordinates. All lisp had to do was swap and ‘{}’ or ‘[]’ for ‘()’ and read it as lisp code then update the image.
(setf in-set (read-from-string (parse-line (uiop:run-program "setl mandelbrot.setl -- -250 -250 250 8" :output :string))))
(draw-mandel instance in-set)
An after-thought was to make a Mandelbrot searcher where you could zoom and move using the mouse but the SETL code is such an inefficient way of doing it that it’s not worth it. As an attempt to mimic the formal definition it was highly successful and fun. Though much quicker SETL code could be written for generating the Mandelbrot Set.
Source file for mandelbrot.setl and the Lisp/CommonQt front end can be found here.
# Accuracy of Generated Fractals
Note: I refer to the Mandelbrot set in general as the M-set for short.
When I was writing the post on Rough Mandelbrot Sets I tried out some variations on the rough set. One variation was to measure the generated M-set against a previously calculated master M-set of high precision (100000 iterations of $z = z^2 + C$). In the image below the master M-set is in white and the generated M-sets are in green (increasing in accuracy):
Here instead of approximating with tiles I measured the accuracy of the generated sets against the master set by pixel count. Where $P = \{ \text{set of all pixels} \}$ the ratio of $P_{master} / P_{generated}$ produced something that threw me, the generated sets made sudden but periodic jumps in accuracy:
Looking at the data I saw the jumps were, very roughly, at multiples of 256. The size of the image being generated was 256 by 256 pixels so I changed it to N by N for N = {120, 360, 680} and the increment was still every ~256. So I’m not really sure why, it might be obvious, if you know tell me in the comments!
I am reminded of the images generated from Fractal Binary and other Complex Bases where large geometric entities can be represented on a plane by iteration through a number system. I’d really like to know what the Mandelbrot Number System is…
Below is a table of the jumps and their iteration index:
Iterations Accuracy measure 255 256 0.241929 0.397073 510 511 0.395135 0.510806 765 766 0.510157 0.579283 1020 1021 0.578861 0.644919 1275 1276 0.644919 0.679819 1530 1531 0.679696 0.718911
# Rough Mandelbrot Sets
I’ve been reading up on Zdzisław Pawlak’s Rough Set Theory recently and wanted to play with them. They are used to address vagueness in data so fractals seem like a good subject.
Super Quick Intro to Rough Sets:
A rough set is a tuple (ordered pair) of sets $R(S) = \langle R_*, R^* \rangle$ which is used to model some target set S. The set $R_*$ has every element definitely in set $S$ and set $R^*$ has every element that is possibly in set $S$ . It’s roughness can be measured by the accuracy function $\alpha(S) = \frac{|R_*|}{|R^*|}$. So when $|R_*| = |R^*|$ then the set is known as crisp (not vague) with an accuracy of 1.
A more formal example can be found on the wiki page but we’ll move on to the Mandelbrot example because it is visually intuitive:
The tiles are 36×36 pixels, the Mandelbrot set is marked in yellow. The green and white tiles are possibly in the Mandelbrot set, but the white tiles are also definitely in it.
Here the target set $S$ contains all the pixels inside the Mandelbrot set, but we are going to construct this set in terms of tiles. Let $T_1, T_2, T_3,\dots , T_n$ be the tile sets that contain the pixels. $R^*$ is the set of all tiles $T_x$ where the set $T_x$ contains at least one pixel that is inside the Mandelbrot set, $R_*$ is the set of all tiles $T_x$ that contain only Mandelbrot pixels. So in the above example there are 28 tiles possibly in the set including the 7 tiles definitely in the set. Giving $R(S)$ an accuracy of 0.25.
Tile width: 90, 72, 60, 45, 40, 36, 30, 24, 20, 18, 15, 12, 10, 9, 8, 6, 5, 4. There seems to be a lack of symmetry but it’s probably from computational precision loss.
Obviously the smaller the tiles the better the approximation of the set. Here the largest tiles (90×90 pixels) are so big that there are no tiles definitely inside the target set and 10 tiles possibly in the set, making the accuracy 0. On the other hand, the 4×4 tiles give us $|R_*| = 1211$ and $|R^*| = 1506$ making a much nicer:
$\alpha(S)$ = $0.8 \overline{04116865869853917662682602921646746347941567065073}$
For much more useful applications of Rough Sets see this extensive paper by Pawlak covering the short history of Rough Sets, comparing them to Fuzzy Sets and showing uses in data analysis and Artificial Intelligence.
# Fractal Binary
I have previously talked about Complex Bases but I wanted to look again at Base (-1+i). It’s a really hefty number system so the length of the bit-strings increase very quickly, I’d quite like to know if there is a way to assess Radix Economy for complex and negative bases, so if there are any mathematicians out there who know – Please tell me!
Visualising Numbers
Today I wrote a little C++ program to act on Base 2 arithmetic but convert to decimal as if it was Base (-1+i), this meant I could increment through the bits in an ‘ordered’ fashion. The image to the left is the text output of the program, it doesn’t have a very obvious pattern to it – infact the pattern-order we derive from it is somewhat an imposed one. This is because complex numbers do not have a linear order (or Total Order) and I’m trying to list them in a linear manner. They can, on the other hand, be Well-Ordered in correspondence with the natural numbers like we’re doing here.
If we take the real and imaginary values of each number and use them as the x and y co-ordinates (like I did for generating the Mandlebrot Set fractal) then the fractal “Twindragon” appears:
The program I wrote runs through binary numbers starting at 0 colouring the pixel (x=r, y=i) discretely depending on number length. The result shows all Gaussian integers representable by all possible 16,12 and 8 bit complex binary strings in base (-1+i). The colour mapping relates to the position of the Most Significant Bit (essentially the bitstring length). 0 and 1 are both of length one and are the dark blue in the center of the fractal. The 12-bit and 8-bit fractal maps have been zoomed in on to emphases the self-similarity of the shape.
Colouring the fractals like this is a nice way of showing the distribution of numbers in the complex system but, going back to the math, a number system isn’t useful without arithmetic. Luckily the (-1+i) system is closed under addition, subtraction and multiplication. For addition and multiplication it is the same as normal binary with the difference being in the carry. Below is a table of all possible carry situations:
1+1 = 1100 1+1+1 = 1101 1+1+1+1 = 111010000 1+1+1+1+1 = 111010001 1+1+1+1+1+1 = 111011100 1+1+1+1+1+1+1 = 111011101 1+1+1+1+1+1+1+1 = 111000000
Division in the systems is rather complex, an explination of that and examples of addition/subtraction/multiplication can be found in a short paper called “Arithmetic in Complex Basis” by William Gilbert. The paper also talks about an equivalent to decimal which is base (-3+i) using the digits [0,1,2,3,4,5,6,7,8,9].
# Complex Bases
Bellow is Donald Knuth, his most famous work is probably The Art of Computer Programming for which the content won him a Turing Award in 1974. He also came up with the Up Arrow notation used in my posts on Large Numbers and God. Those posts were inspired by one of Knuth’s books, this post was inspired by his number system.
The Quater-Imaginary System
As a student at High School he entered into a science talent search and his submission was the Quater-Imaginary system, or Base 2i. It’s interesting because it uses the digits {0,1,2,3} for representation so it would seem at first glance to be quaternary (Base 4) – but it’s not!
It is actually an imaginary base, as the complex version is (0r±2i). Like the decimal system, quater-imaginary can finitely reperesent all positive real integers -but it can do more- it can finitely represent all positive AND negative real AND imaginary integers without signs (i.e., 3i, -8). Which can be seen in this table:
Base 10 Base 2i Base 10 Base 2i Base 10 Base 2i Base 10 Base 2i 1 1 -1 103 1i 10.2 -1i 0.2 2 2 -2 102 2i 10.0 -2i 1030.0 3 3 -3 101 3i 20.0 -3i 1030.2 4 10300 -4 100 4i 20.0 -4i 1020.0 5 10301 -5 203 5i 30.2 -5i 1020.2
The Dragon System
The Twindragon also known as the Davis-Knuth dragon!
It’s not offically called that, but the second most known complex system is Base (−1±i) which has an associated fractal shape (twindragon). It uses the numbers {0,1} for representation. It’s a very clean and eligant number system that was created by Walter F. Penney in 1965. As with quater-imaginary, this number system can be used to finitely represnt the Gaussian Integers.
Interestingly the radix starts with a negative number, but this isn’t a problem, negative bases work just aswell as positive ones. Infact in 1957 a Polish computer called BINEG was designed using negabinary!
Base 10 Base (-1±i) Base -2 Base 2 1 1 1 1 2 1100 110 10 3 1101 111 11 4 111010000 100 100 5 111010001 101 101
Base (-1±i√7)/2 and Others
Here the length of the numbers don’t increase monotonically, for example 12(11001100) and 13(11001101) are shorter than their predecessor 11(11100110011) which is the same length as 14(11100010110). It isn’t the only base to hold this attribute but it’s one of the quickest to show it. Source and explination here.
As well as whole-number radix systems it is possible to use fractions and even irrational numbers, one example I go over is Phinary (Base 1.61803…) also known as the Golden Ratio Base. On my Research Page I am looking at a series of systems, starting with the golden ratio, which I call the Metallic Series that can all be used under the same rules.
I find number systems quite interesting and I have started messing around modelling them in different ways, in a previous post (Numeral Automata) I look at them using cellular automata.
# Randolph Diagrams
This is what a genius looks like.
There is something aesthetic and elegant about Randolph diagrams, unfortunately they aren’t commonly used. I found out about them when reading Embodiments of Mind by the glorious and bearded Warren McCulloch.
The Original Proposal:
In the book he refers to them as “Venn functions” and they are briefly explained as being derived from Venn’s diagrams for sets but in McCulloch’s case they were used to express logical statements. If you draw a Venn diagram of two circles intersecting you are left with four spaces ( a/b, a&b, b/a, U ), adding a jot into a space to denote truth or leaving it blank for false gives you the 16 possible logic combinations. They are great examples of the isomorphism between logic and set theory:
He used these as tools to help teach logic to neurologists, psychiatrists and psychologists. Later he developed them into a probablistic logic which he applied to John vonn Neumann‘s logical neuron nets. Which I will discuss in the next post.
Randolph’s Diagrams:
The truth values for three statements.
McCulloch does mention that they could be used to apply more than two statements but doesn’t show how, later John F. Randolph developes the system as an alternative visualisation of set relations neatly coping with more than two sets (something Venn diagrams begin to struggle with after five). For each additional statement/set a new line is introduced in each quadrant. Four statements would be a large cross with four smaller crosses, one in each quadrant.
Wikipedia has an example of the tautological proof for the logical argument, modus ponens, which can be found here, but I thought it would be good to show how three values are handled – so we’ll use syllogism, as in “Socrates is a man, all men are mortal, therefore Socrates is mortal” being reduced in it’s logical form to tautology:
((A implies B) and (B implies C)) implies (A implies C)
# Numeral System Automata
Cellular Automata
Cellular automata Is made up of a grid of cells which sit in a finite number of states (such as on/off or blue/green/red). Cellular automaton (singular) adhear to the rules of the system and evolve over periodic time intervals. One successful application of CA is Conway’s Game of Life, the universe is an infinite 2D grid and the rules are as follows:
A single Gosper's Glider Gun creating "gliders"
1. Any live cell with fewer than two live neighbours dies, as if by needs caused by underpopulation.
2. Any live cell with more than three live neighbours dies, as if by overcrowding.
3. Any live cell with two or three live neighbours lives, unchanged, to the next generation.
4. Any dead cell with exactly three live neighbours cells will come to life.
Positional Number Systems
We use these all the time, notably the decimal system in which when a symbol exceeds 9 it “carries” one to the left and negates ten. 9+1=A, then A goes to 10.
$a_n \dots a_2a_1a_0 = (a_n {\times} b^n) + \dots + (a_2 {\times} b^2) + (a_1 {\times} b^1) + (a_0 {\times} b^0)$
Example: $1250 = (1 \times 10^3) + (2 \times 10^2) + (5 \times 10^1) + (0 \times 10^0)$
The Idea
To take the properties of a number system and create rules to govern individual cells. For our numeral universe we are going to need something different to what Conway used, ours is going to have an intrinsic property, gravity – and thus a floor to gravitate to. The center of our universe will be the radix point (decimal point), you could say the numeral universe is radixocentric. The real-life universe is made up of multiple dimensions, the numeral one is made up of infinite column dimensions.
Although initially I will only being dealing with addition and thus carry, I have put on paper negation in phinary which was quite fun. I talk about the arithmetic of phinary in my research (section 4). The Numeral Universe rules and an example are below:
1. Positional System – Each dimensional element (cell) is the value of the previous dimension’s capacity.
2. Gravity – Any cell above an empty cell moves to it.
3. Carry – When a dimension is full, it moves to the next higher one.
Example in base 3 (ternary). The green and red blocks are the two numbers being added to the universe, the grey block is the carry.
But what does this all mean?
Well, I’m not really sure – it’s nice to show number systems in a different way, it could be useful for teaching. But as for me, I’m using the rules to govern an alternative tetris game, I’ll upload it when I’m finnished.
Also if anyone is wondering how I made those fractal looking blocks, I spammed the hell out of the filters on Pixlr the free online image editor.
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https://www.physicsforums.com/threads/calculating-q-dot.278455/
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# Calculating Q (dot)
1. Dec 9, 2008
### skaboy607
Hi
Wondering if someone could help me satisfy my curiosity. Hopefully a very simple for someone who knows. I have been given values for Voltage and Current. To calculate Q (dot), I know Q(dot)=V * A. The units for this are Watts / J/s / Nm/s.. How can Voltage multiplied by a current provide these units?
Thanks
William
2. Dec 9, 2008
### tiny-tim
Welcome to PF!
Hi William! Welcome to PF!
From electric units in the PF Library
Power = voltage.current = energy/time (dim. $ML^2/T^3$):
$$\text{W}\ \equiv\ \text{watt}\ \equiv\ \frac{\text{J}}{\text{s}}\ \equiv\ \frac{\text{joule}}{\text{second}}\ \equiv\ \frac{\text{N.m}}{\text{s}}\ \equiv\ \frac{\text{newton.metre}}{\text{second}}\ \equiv\ \text{V.A}\ \equiv\ \text{volt.amp}\ \equiv\ \Omega\text{.A}^2\ \equiv\ \text{ohm.amp}^2$$
3. Dec 9, 2008
### skaboy607
Thank you very much. Good to of joined.
Thats that sorted then, thanks for clearing up.
William
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http://mathhelpforum.com/pre-calculus/186555-writing-sum-using-sigma-notation.html
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# Thread: Writing the Sum Using Sigma Notation
1. ## Writing the Sum Using Sigma Notation
Alright, it goes hand-in-hand with a previous topic titled "Summation Formulas" but yet...it's different at the same time.
This time they give me two series:
1. $1+1/2+2+5/2+...+6$
2. $[1-(1/2)^2]+[1-(1/3)^2]+[1-(1/4)^2]+...$
My first reaction was that I would have to find the formula myself, where it starts, and where it ends. Simple...except not so much.
The second one is possibly $\sum_{n=1}^{INF}([1-(1/(1+N)^2])$.
Although that would be way to simple, hehe.
The first one though, I can't seem to find a proper equation that fits the numbers given.
2. ## Re: Writing the Sum Using Sigma Notation
The answer to the second one is correct.
You could even say $\displaystyle \sum_{n=2}^{\infty}1-\frac{1}{n^2}$
Can't see a pattern in the first one yet.
3. ## Re: Writing the Sum Using Sigma Notation
Yeah, I dunno what's going on with the first one. I spent at least an hour or two going over it but it's harder then it looks...and it looked pretty hard to start with.
Oh, I also made a mistake on number one, accidently left out a number. Fixed it.
Should be:
$1+\frac{1}{2}+2+\frac{5}{2}+...+6$
4. ## Re: Writing the Sum Using Sigma Notation
Originally Posted by UnstoppableBeast
Alright, it goes hand-in-hand with a previous topic titled "Summation Formulas" but yet...it's different at the same time.
1. $1+{\color{red}1}/2+2+5/2+...+6$
I think it ought to be $1+\frac{{\color{blue}3}}{2}+2+\frac{5}{2}+\cdots+6$.
In which case it would be $\sum\limits_{k =1}^{11} {\frac{{k + 1}}{2}}$
5. ## Re: Writing the Sum Using Sigma Notation
Is it possible the second term has to be $\frac{3}{2}$ in stead of $\frac{1}{2}$?
6. ## Re: Writing the Sum Using Sigma Notation
Sadly no. It would've been easier that way but I'm sure of what the question is asking, I have the paper right in front of me.
Maybe the person who made the packet made a mistake, seems as likely as anything.
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http://mathhelpforum.com/trigonometry/105730-3-hard-trigonometry-questions.html
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# Math Help - 3 Hard Trigonometry Questions
1. ## 3 Hard Trigonometry Questions
Here are the questions (image below). Visual representations of the answers would be much appreciated!
2. Hello, yeah!
#2 took a lot of work . . . #3 is similar.
Maybe someone else can find a more direct solution.
2. The angle of elevation of the top of a tower is 38° from a point A south of it.
The angle of elevation of the top of the tower is 29° from a point B east of it.
Find the height of the tower if the distqance AB is 50m.
Code:
P
o
*| *
* | *
* | *
* |h *
* | *
* | *
* | x 29° *
* o * * * * * o B
*38° * Q *
* * y * 50
* * *
A o
The tower is: $h = PQ.$
$\angle PAQ = 38^o,\;\angle PBQ = 29^o$
$\angle AQB = 90^o,\;AB = 50\text{m}$
Let: $x = QB,\;y = QA$
In right triangle $PQA\!:\;\tan38^o \:=\:\frac{h}{y} \quad\Rightarrow\quad h \:=\:y\tan38^o$ .[1]
In right triangle $PQB\!:\;\;\tan29^o \:=\:\frac{h}{x} \quad\Rightarrow\quad h \:=\:x\tan29^o$ .[2]
Equate [1] and [2]: . $y\tan38 \:=\:x\tan29 \quad\Rightarrow\quad y \:=\:\frac{\tan29}{\tan38}\,x$ .[3]
In right triangle $AQB\!:\;\;x^2+y^2 \:=\:50^2$
Substitute [3]: . $x^2 + \left(\frac{\tan29}{\tan38}\,x\right)^2 \:=\:2500 \quad\Rightarrow\quad x^2 + \frac{\tan^229}{\tan^238}\,x^2 \:=\:2500$
. . $x^2\left(1 + \frac{\tan^229}{\tan^238}\right) \:=\:2500 \quad\Rightarrow\quad x^2\left(\frac{\tan^238 + \tan^229}{\tan^238}\right) \:=\:2500$
. . $x^2 \:=\:\frac{2500\tan^238}{\tan^238 + \tan^229} \quad\Rightarrow\quad x\;=\;\frac{50\tan38}{\sqrt{\tan^238 + \tan^229}}$
Substitute into [2]: . $h \;=\;\frac{\tan29}{\tan38}\cdot\frac{50\tan38}{\sq rt{\tan^238 + \tan^229}}$
. . Grab your calculator . . .
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https://www.scielo.br/j/mioc/a/ZYNdbFw3sY89PMfgLDSS9zP/?format=html&lang=en
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Abstract
This study describes the genetic relationships of the first human astrovirus type-8 (HAstV-8) detected in Belém-Brazil, during a public hospital-based study. This strain was compared with other HAstV-8 strains identified elsewhere which have sequences available at GeneBank. The regions ORF1a (primers Mon348/Mon340) and ORF2 (primers Mon269/Mon270) were analyzed by nucleotide sequencing and a high similarity rate was observed among the Belém strain and other HAstV-8 strains. In ORF1a, homology values of 93-100% were detected, and in ORF2 96-99%. Considering the sequence variation (7%) observed in ORF2 region, it was suggested that HAstV-8 strains could be divided in three different lineages.
astrovirus type 8; molecular characterization; Belém; Brazil
astrovirus type 8; molecular characterization; Belém; Brazil
ARTICLES
First detection of a human astrovirus type 8 in a child with diarrhea in Belém, Brazil: comparison with other strains worldwide and identification of possible three lineages
Yvone B GabbayI, + + Corresponding author: [email protected] ; Alexandre C LinharesI; Darleise S OliveiraI; Lilian S NakamuraI, ++ ++ CNPq fellowship ; Joana D'Arc P MascarenhasI; Rosa Helena P GusmãoII; Marcos B HeinemannIII; Olinda MacêdoI; José Paulo G LeiteIV
ISeção de Virologia, Instituto Evandro Chagas, Secretaria de Vigilância em Saúde, Ministério da Saúde, BR 316 Km 7, s/nº, 67030-000 Ananindeua, PA, Brasil
IIIEscola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
IVDepartmento de Virologia, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil
ABSTRACT
This study describes the genetic relationships of the first human astrovirus type-8 (HAstV-8) detected in Belém-Brazil, during a public hospital-based study. This strain was compared with other HAstV-8 strains identified elsewhere which have sequences available at GeneBank. The regions ORF1a (primers Mon348/Mon340) and ORF2 (primers Mon269/Mon270) were analyzed by nucleotide sequencing and a high similarity rate was observed among the Belém strain and other HAstV-8 strains. In ORF1a, homology values of 93-100% were detected, and in ORF2 96-99%. Considering the sequence variation (7%) observed in ORF2 region, it was suggested that HAstV-8 strains could be divided in three different lineages.
Key words: astrovirus type 8 - molecular characterization - Belém - Brazil
Human astrovirus (HAstVs) belongs to the Astroviridae family, and are classified in the genus Mam-astrovirus(Monroe et al. 2005). They are small, round non-enveloped viruses, 28 nm in diameter and composed of a single-stranded positive-sense RNA genome (ssRNA). The genome contains three open reading frames (ORFs) designated ORF1a, ORF1b, and ORF2, as well as terminal non-coding regions (NCR). ORF1a and 1b encode non-structural proteins, including a serine protease (Pro) and RNA-dependent RNA polymerase (Pol), respectively, and these regions contain highly conserved sequences. ORF2 is located at the 3' end of the genome, encodes the capsid protein precursor, and is highly variable (Matsui & Greenberg 2001, Walter et al. 2001).
HAstVs were classified into eight genotypes based on the nucleotide sequence analysis of a 348-bp region of ORF2 (Mustafa et al. 2000). These eight genotypes showed good correlation with the eight serotypes determined according to the reactivity of the capsid proteins with type-specific monoclonal antibodies (Sakamoto et al. 2000, Taylor et al. 2001).
For the eight types of HAstV already reported, the HAstV-1 is considered the most prevalent and HAstV-6, 7, and 8 as the seldom detected (Mustafa et al. 2000, Guix et al. 2002, Méndez-Toss et al. 2004). After the description of the prototype HAstV-8 (Z66541) in United Kingdom in 1995, the first reports describing the detection of this type of virus relate to the occurrence of single isolates like those occurring in Ghaza and Uganda (Monceyron et al. 1997), Pakistan (Sakamoto et al. 2000), Australia (Nadan et al. 2003) and, more recently, in the United States (acces. nos AY304469 and AY304470), Brazil (Silva et al. 2006, and acces. nos DQ381506 to DQ381508), and India (acces. nos AB116554, AB126670 to 126674, AB191789, AB194280, and AB211059). Studies conducted in Egypt, Spain, Korea, South Africa, Hungary, and Mexico demonstrated the presence of HAstV-8 in percentages that varied from 8 to 23%, considering the total of positive cases detected (Naficy et al. 2000, Guix et al. 2002, Kang et al. 2002, Nadan et al. 2003, Méndez-Toss et al. 2004, Jakab et al. 2004).
One strain of HAstV-8 (PA-NSC087-BR) was detected in Belém, North of Brazil, during a study conducted in a public hospital from November 1992 to November 1994 involving children aged 0-5 years, who were admitted with acute gastroenteritis (Gusmão et al. 1999). Such HAtV-8 isolate was obtained from a seven-month old female with acute diarrhea of four-day duration, which persisted for eight more days. Moderate dehydration was identified during the first 48 h of hospitalization. In addition, fever was recorded in the first day and acute respiratory infection was diagnosed on the second and third days of admission. A diarrheic stool sample was obtained four days after admission (March 1st, 1993), being stored at Instituto Evandro Chagas, at - 20ºC, until being processed.
This was the first time that a HAstV-8 was detected in Belém. Furthermore, this type has rarely been detected worldwide (Guix et al. 2002, Méndez-Toss et al. 2004), and up to now, only two studies described molecular analysis of the HAstV-8 strains (Méndez-Toss et al. 2000, Taylor et al. 2001). The aim of this report is therefore to describe the antigenic and genetic relationships of this HAstV-8 strain (PA-NSC087-BR), in light of comparison with other HAstV-8 strains identified elsewhere, to gathering more complete characterization data on this type. This is the first approach to compare different strains of HAstV-8 already described in relation to the ORF1a and 5' end ORF2 region of the HAstV-8.
The specimens collected in this study were screened for the presence of HAstV antigen by a commercial qualitative enzyme immunoassay (EIA) kit (IDEIATM Dako Cytomation, Ely, UK), with subsequent confirmation by reverse transcription-polymerase chain reaction (RT-PCR) using specific primers Mon 269 (4526-4545 nt) and Mon 270 (4955-4974 nt), yielding an expected product size of 449 nt in the 5' end of ORF2, as described previously by Noel et al. (1995) with few modifications (Gabbay et al. 2005). The positive samples by RT-PCR were genotyped by two methodologies: the type-specific RT-PCR using primers described by Sakamoto et al. (2000), that amplified the 3' end region of ORF2, and by the nucleotide sequencing of RT-PCR astrovirus amplicons that was carried out under the conditions described by Gabbay et al. (2005), with the primers Mon 269 / Mon 270. Another pair of primers (Mon 348 / Mon 340), directed towards the ORF1a (Belliot et al. 1997), was also used with the HAstV-8 sample, to obtain data from another region of the genome, therefore broadening the phylogenetic analysis. Sequence data obtained with sample PA-NSC087-BR with primers Mon 269 / Mon 270 were aligned and edited using BioEdit Sequence Alignment Editor (v.7.0.5.2) program and compared with the eight prototype sequences (HAstV1 [L23513], HAstV2 [L13745], HAstV3 [L38505], HAstV4 [L38506], HAstV5 [U15136], HAstV6 [L38507] and HAstV7 [L38508], Oxford reference strains and HAstV-8 [Z66541], United Kingdom reference) and with the strains Yuc-8 (AF260508), AS20 (AF292079), Melb8A (AF175261), RJ8398/BR/04 (DQ381508), Bcn8-5 (AF34880), BrG8 (DQ139832) and RJ8163/BR/04 (DQ381507) obtained from GenBank (www.ncbi.nlm.nih.gov), using the BLAST program. The sequence data obtained with sample PA-NSC087-BR with primers Mon 340 / Mon 348 were aligned with the sequences AS20 (AF290509), KS106205 (AF361030), KS106207 (AF361032), HAstV-2 (L13745), BrG5 (DQ028633), HAstV-3 (AF141381), HAstV-1 (L23513), BrG4 (DQ070852), V770/2002 (AB126670), I/V813/2002 (AB126672), Yuc-8 (AF260508), HAstV-6 (AF290507), HAstV-7 (AF290508). Phylogenetic trees were constructed by neighbor-joining method using the Mega (v. 3.1) software, supported by bootstrap using 2000 replicates. The nucleotide sequences determined in this study have been deposited in the GenBank database and assigned the accession numbers DQ990460 and DQ990461.
All the specimens of this study were tested for the presence of bacteria and parasites following the specifications of the " WHO Manual for Laboratory Investigation of Acute Enteric Infections, Programme for Control of Diarrhoeal Diseases ". Samples were also tested for rotavirus antigen using a commercial EIA (DAKO-PATTS EIA kits-Copenhagen, Denmark), and for calicivirus using the RT-PCR technique including a pair of primers p289 and p290 as described by Jiang et al. (1992).
After the detection of HAstV by both EIA and RT-PCR, the sample PA-NSC087-BR was tested by the type-specific PCR that assigned this sample as a HAstV-8. Nucleotide sequence analyses using the pair of primers Mon 269/Mon 270 and Mon 340/Mon 348 confirmed this strain as belonging to genotype 8. A good correlation between these two methodologies was also demonstrated in studies conducted in a periurban community of Mexico City and Hungary for all genotypes (Walter et al. 2001, Jakab et al. 2004).
Phylogenetic trees based on the 348-bp fragment of the ORF2 region (Fig. 1A) and on the 246-bp fragment of the ORF1a region (Fig. 1B) were constructed to assess the genetic relatedness between the PA-NSC087-BR strain and other available sequences of HAsTV-8 obtained from different countries.
Analysis of the ORF1a region showed that PA-NSC087-BR group together with the other HAstV-8 genotypes as well as with genotypes HAstV-1 to HAstV-5 in a genogroup A, as defined by Belliot et al. (1997) and Taylor et al. (2001). Comparing the strain PA-NSC087-BR with the strain Yuc-8, a 97% nt and a 100% aa similarities were observed. With the other HAstV-8 (AS20, KS106205, KS106207, and V813/2002) the similarities were 93-94% at nt level and 96-99% at aa level. In one HAstV-8 sample from India (V770/2000), the sequence described in GeneBank for ORF1a region was a little small (220 bp), and when it was compared with the strain PA-NSC087-BR a similarity of 93% in nt and of 98% in aa was seen. The comparison of the strain PA-NSC087-BR with the strain classified as HAstV-1, 2, 3, 4, and 5 showed significant homology (90-93% in nt and 96-97% in aa), in contrast with HAstV types 6 and 7 where similarity was lower (80% nt and 92-95% aa).
As previously demonstrated (Belliot et al. 1997, Taylor et al. 2001), the nucleotide sequence analysis of ORF1a region from HAstV-1 to HAstV-8 indicate that HAstVs fall into two distinct genogroups. This fact was also observed in this study however, we did not verify a high similarity between HAstV-8 and HAstV-4 strains, as reported by Taylor et al. (2001). This may be explained by the fact that HAstV-4 strain used in our analysis was different from that utilized in that research.
Considering the amino acid sequence of the ORF1a region, the strain PA-NSC087-BR demonstrated a pattern similar to that of strain Yuc-8, and a difference of one (V770/2002 and V834/2000), two (AS20 and KS106207), and three (KS106205) amino acids as compared to other strains sequenced (Fig. 2A).
Analysis of the ORF2 region indicates that PA-NSC087-BR strain has a higher pairwise similarity with the strain SXPAKAS706 (99% in nt), and with the other strains (Yuc-8, AS20, RJ8398, Bcn8-5, BrG8, Melb8A), of 96-98% in nt. A divergence of 6% in nt sequence was noted in relation to the HAstV-8 prototype, and of 7% with the HAstV-8 strain RJ8163. Based on the sequence variations observed among strains of a same type, some authors (Medina et al. 2000, Guix et al. 2002) have proposed that strains showing a sequence diversity of at least 7% could be classified as new lineages. Using this same criterion, we observed, as for the ORF2 region, HAstV-8 could be divided in three different lineages and two of these were detected in Brazil (Fig. 1A).
In relation to the amino acid sequence, a similarity of 100% was noted in the ORF2 region, when comparing the PA-NSC087-BR strain with the other HAstV-8 strains (Pakistan, Mexico, South Africa, Brazil, and Spain), except for Melb8A (97%) and RJ8163 (91%) strains. When comparing to the HAstV-8 prototype, the similarity was of 91%. The comparison between PA-NSC087-BR strain and HAstV-1 to 7 denotes a closer relationship with HAstV-4 (similarity of 90% nt and 99% aa) than with the other types (similarity 78-82% nt and 91-96% aa). This is in agreement with observations made by Taylor et al. (2001) during the characterization of the strain AS20 from South Africa, and by Mendéz-Toss et al. (2000) during an analysis of Yuc-8 strain from Mexico.
Comparing the fragment of 348-bp of the ORF2 region obtained from the HAstV-8 prototype with those from PA-NSC087-BR, PAKAS706, Yuc-8, AS20, RJ 8398, Bcn8.5, and BrG8 strain, a difference of 10 amino acids was observed (Fig. 2B). The strains Melb8A and RJ8163 showed a difference to the prototype of 9 and 19 amino acids, respectively. This clearly demonstrated the great difference between the prototype and the other type 8 strains circulating worldwide and sustains the classification of this type into three lineages. The significant correlation (97 to 99%) observed between the strain detected in Belém and other from various countries (Pakistan, Mexico, South Africa, Spain, and Brazil), suggests that a genetically similar HAstV-8 strain was circulating in these several countries.
No other enteropathogen was detected in the PA-NSC087-BR sample, suggesting that astrovirus had a role in the etiology of diarrhea. Of note, the clinical course appeared to be more severe than it has previously been appreciated (Nadan et al. 2003).
We cannot rule out the possibility of a nosocomial infection since the fecal sample of this child was obtained four days after admission; however, there is a strong evidence of community-acquired infection because we had a single HAstV-8 detection into the ward environment. It is important to mention that during this study a total of 372 specimens were tested yielding an astrovirus positivity of 8.9% (33/372), and with the detection of three HAstV-1 nosocomial infections.
In summary, we characterized the first case of HAstV-8 isolate in Belém, Brazil, emphasizing that comparison of sequences obtained from the ORF2 region allowed us to sustain the existence of three distinct lineages within HAstV-8.
ACKNOWLEDGMENTS
To the valuable technical support provided by Maria Silvia de Lucena.
Accepted 22 March 2007
Financial support: IEC/SVS/MS, IOC-Fiocruz, SECTAM/Funtec/PA, Pibic/CNPq
• Belliot G, Laveran H, Monroe SS 1997. Detection and genetic differentiation of human astroviruses: phylogenetic grouping varies by coding region. Arch Virol 142: 1323-1334.
• Gabbay YB, Luz CRNE, Costa IV, Cavalcante-Pepino EL, Sousa MS, Oliveira KK, Wanzeller ALM, Mascarenhas JDP, Leite JPG, Linhares AC 2005. Prevalence and genetic diversity of astrovirus in children with and without diarrhea in São Luís, Maranhão, Brazil. Mem Inst Oswaldo Cruz 100: 709-714.
• Guix S, Caballero S, Villena C, Bartolome R, Latorre C, Rabella N, Simo M, Bosch A, Pinto M 2002. Molecular epidemiology of astrovirus infection in Barcelona, Spain. J Clin Microbiol 40: 133-139.
• Gusmão RHP, Mascarenhas JDP, Gabbay YB, Lins-Laison ZC, Ramos FLP, Monteiro TAF, Valente SA, Fagundes-Neto U, Linhares AC 1999. Rotavirus subgroups, G serotypes, and electrophoretypes in cases of nosocomial infantile diarrhoea in Belém, Brazil. J Trop Pediat 45: 81-86.
• Jakab F, Meleg E, Bányai K, Melegh B, Tímár L, Péterfai J, Szücs G 2004. One-year survey of astrovirus infection in children with gastroenteritis in a large hospital in Hungary: occurrence and genetic analysis of astroviruses. J Med Virol 74: 71-77.
• Jiang X, Wang J, Graham DY, Estes MK 1992. Detection of Norwalk virus in stool by polimerase chain reaction. J Clin Microbiol 30: 2529-2534.
• Kang Y-H, Park Y-K, Ahn J-B, Yeun J-D, Jee Y-M 2002. Identification of human astrovirus infections from stool samples with diarrhea in Korea. Arch Virol 147: 1821-1827.
• Matsui SM, Greenberg HB 2001. Astroviruses. In DM Knipe, PM Howley (eds), Fields Virology, 4th ed., Lippincott, Williams and Wilkins, Philadelphia, p. 875-893.
• Medina SM, Guitierrez MF, Liprandi F, Ludert JE 2000. Identification and type distribution of astroviruses among children with gastroenteritis in Colombia and Venezuela. J Clin Microbiol 38: 3481-3483.
• Méndez-Toss M, Griffin DD, Calva J, Contreras JF, Puerto FI, Mota F, Guiscafre H, Cedillo R, Munoz O, Herrera I, Lopez S, Arias CF 2004. Prevalence and genetic diversity of human astroviruses in Mexican children with symptomatic and asymptomatic infections. J Clin Microbiol 42: 151-157.
• Méndez-Toss M, Romero-Guido P, Munguía ME, Méndez E 2000. Molecular analysis of a serotype 8 human astrovírus genoma. J Gen Virol 81: 2891-2897.
• Monceyron C, Grinde B, Jonassen TØ 1997. Molecular characterization of the 3'-end of the astrovirus genome. Arch Virol 142: 699-706.
• Monroe SS, Carter MJ, Herrmann JE, Mitchell DK, Sanchez-Fauquier A 2005. Family Astroviridae In CM Fauquet, MA Mayo, J Maniloff, U Desselberger, LA Ball (eds), Virus Taxonomy: Eighth Report of the International Committee on Taxonomy of Viruses, Elsevier/Academic Press, London, p. 859-864.
• Mustafa H, Palombo EA, Bishop RF 2000. Epidemiology of astro-virus infection in young children hospitalized with acute gastroenteritis in Melbourne, Australia, over a period of four consecutive years, 1995 to 1998. J Clin Microbiol 38: 1058-1062.
• Nadan S, Walter JE, Grabow WOK, Mitchell DK, Taylor MB 2003. Molecular characterization of astroviruses by reverse transcriptase PCR and sequence analysis: comparison of clinical and environmental isolates from South Africa. Appl Environ Microbiol 69: 747-753.
• Naficy AB, Rao MR, Holmes JL, Abu-Elyazeed R, Savarino SJ, Wierzba TF, Frenck RW, Monroe SS, Glass RI, Clements JD 2000. Astrovirus diarrhea in Egyptian. J Infect Dis 182: 685-690.
• Noel JS, Lee TW, Kurtz JB, Glass RI, Monroe SS 1995. Typing of human astroviruses from clinical isolates by enzyme immunoassay and nucleotide sequencing. J Clin Microbiol 33: 797-801.
• Sakamoto T, Negidhi H, Wang QH, Akihara S, Kim B, Nishimura S, Kaneshi K, Nakaya S, Ueda Y, Sugita K, Motohiro T, Nishimura T, Ushijima H 2000. Molecular epidemiology of astroviruses in Japan from 1995 to 1998 by reverse transcription-polymerase chain reaction with serotype-specific primers (1 to 8). J Med Virol 61: 326-331.
• Silva PA, Cardoso DDP, Schreier E 2006. Molecular characterization of human astroviruses isolated in Brazil, including the complete sequences of astrovirus genotypes 4 and 5. Arch Virol 151: 1405-1417.
• Taylor MB, Walter J, Berke T, Cubitt WD, Michell DK, Matson DO 2001. Characterization of a South African human astrovirus as type 8 by antigenic and genetic analyses. J Med Virol 64: 256-261.
• Walter JE, Mitchell DK, Guerreiro ML, Berke T, Madison DO, Monroe SS, Pickering LK, Ruiz-Palacios G 2001. Molecular epidemiology of human astrovirus diarrhea among children from a periurban community of Mexico city. J Infec Dis 183: 681-683.
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Corresponding author:
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CNPq fellowship
Publication Dates
• Publication in this collection
19 Apr 2007
• Date of issue
June 2007
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http://mathoverflow.net/questions/48488/how-does-the-mixing-time-of-a-geodesic-flow-on-a-surface-vary-with-the-genus
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# How does the mixing time of a geodesic flow on a surface vary with the genus?
I have been looking at the numerical behavior of a particular quantity (of no direct importance here, though if you must know the gory details start with figure 17 here) associated to the geodesic flow on a surface of constant negative curvature and genus $g$. The behavior is quantitatively similar for $g = 2,3,4$ and physical intuition based on this quantity suggests that some "intrinsic" timescale--prime candidates are the mixing or relaxation time--should therefore depend on $g$ only weakly or even not at all.
So: what is known about the behavior of the mixing and relaxation (or similar) times associated to these flows as $g$ varies?
-
There are many different metrics of curvature -1 on a surface of genus g. Do you have particular metrics in mind? For surfaces of genus 2, the mixing time can go to infinity as you vary the metric: if there are two genus-one subsurfaces separated by a long thin tube, the portion of the unit tangent bundle on one side takes a long time to mix with the portion on the other side. – Bill Thurston Dec 8 '10 at 23:58
Let's say for concreteness that the surface of constant negative curvature is given by a identifying appropriate edges of a regular $8g-4$-gon in the disk model with metric $ds^2 = dz d\bar{z}/(1-|z|^2)^2$. – Steve Huntsman Dec 9 '10 at 0:59
@Steve -- do you mean the regular $4g$-gon? The rate of mixing has to depend on $g$, because the surface that the $4g$-gon gives has injectivity radius an increasing function of $g$. (It grows like $\log(g)$.) – Sam Nead Dec 9 '10 at 10:30
@Sam--thanks. I mean $8g-4$: see imgur.com/XDADm.png for the edge identification. – Steve Huntsman Dec 9 '10 at 13:45
@Steve - Thank you for the figure. So you are using the regular, right angled, $8g−4$-gon. Let's call it $P$. If you draw $P$ in the most symmetric fashion in the disc model of $H^2$ then the center $O \in P$ will be distance $\log(g)$ (more or less) from the boundary of $P$. So for subsets of the unit tangent "close to" the point $O$ you'll have to flow for at least that long before any mixing at all happens. – Sam Nead Dec 9 '10 at 18:13
Here is another thought that struck me on the way home, that I should have realized earlier. Suppose that $S$ is a closed hyperbolic surface, of genus $g$. Then the area of $S$ is $-2\pi\chi(S) = 2\pi(2g - 2)$. Since the area of a disk in the hyperbolic plane is exponential in its radius, it follows that the diameter of $S$ is at least logarithmic in $g$. The mixing time of a space has to be at least the diameter, right? So this gives a uniform lower bound on the mixing time.
Thurston's comment is pointing out that there is no uniform upper bound. To see this: The injectivity radius is one-half the systole (the length of the shortest closed geodesic). For a hyperbolic surface, the collar lemma implies that as the injectivity radius goes to zero the diameter goes to infinity (this is the previously mentioned "long thin tube"). Thus the mixing time also has to grow, by the previous paragraph.
I roughly expect the mixing time can be estimated from the logarithm of the genus and the inverse of the injectivity radius. One reference for the geometric facts above is Peter Buser's book "Geometry and spectra of compact Riemann surfaces".
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OK, so I wanted to elaborate here on Sam's helpful comments.
Set $N = 8g-4$. An explicit description of the $N$-gon $F$ that I have in mind is $$F = D \ \backslash \ \bigcup_{j=1}^{N} \left(\sqrt{a-1} \cdot D + \sqrt{a} e^{2\pi i(j-2g)/N}\right)$$ with $a = \sec \frac{2\pi}{N}$. In particular, the nearest point to the origin is at a Euclidean distance $u := \sqrt{a} - \sqrt{a-1}$, so the hyperbolic distance is $d = \int_0^u \frac{dr}{1-r^2} = \frac{1}{2}\log\frac{1+u}{1-u}$, which evidently grows as $\log g$.
A bit more context also: I expect that $t_g f(g) \approx const$, where $t_g$ is whatever timescale and $f(g)$ is the quantity mentioned in the question. If $t_g \sim \log g$ then I'd expect that $f(g) \sim 1/\log g$, which is actually a weak enough dependence on $g$ to not be surprising based on the numerics alluded to in the question.
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http://www.airports-worldwide.com/articles/article0590.php
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Lagrangian point
By Wikipedia,
the free encyclopedia,
http://en.wikipedia.org/wiki/Lagrangian_point
A contour plot of the effective potential of a two-body system (the Sun and Earth here) due to gravity and the centrifugal force as viewed from the rotating frame of reference in which Sun and Earth remain stationary. Objects revolving with the same orbital period as the Earth will begin to move according to the contour lines showing equipotential surfaces. The arrows indicate the gradients of the potential around the five Lagrange points — downhill toward or away from them, but at the points themselves these forces are balanced.
The Lagrangian points (pronounced /ləˈɡreɪndʒiən/; also Lagrange point, L-point, or libration point), are the five positions in an orbital configuration where a small object affected only by gravity can theoretically be stationary relative to two larger objects (such as a satellite with respect to the Earth and Moon). The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to rotate with them. They are analogous to geostationary orbits in that they allow an object to be in a "fixed" position in space rather than an orbit in which its relative position changes continuously.
A more precise but technical definition is that the Lagrangian points are the stationary solutions of the circular restricted three-body problem. For example, given two massive bodies in circular orbits around their common center of mass, there are five positions in space where a third body, of comparatively negligible mass, could be placed which would then maintain its position relative to the two massive bodies. As seen in a rotating reference frame with the same period as the two co-orbiting bodies, the gravitational fields of two massive bodies combined with the centrifugal force are in balance at the Lagrangian points, allowing the third body to be stationary with respect to the first two bodies.
## History and concepts
The three collinear Lagrange points were first discovered by Euler around 1750.
In 1772, the Italian-French mathematician Joseph-Louis Lagrange was working on the famous three-body problem when he discovered an interesting quirk in the results. Originally, he had set out to discover a way to easily calculate the gravitational interaction between arbitrary numbers of bodies in a system, because Newtonian mechanics concludes that such a system results in the bodies orbiting chaotically until there is a collision, or a body is thrown out of the system so that equilibrium can be achieved. The logic behind this conclusion is that a system with one body is trivial, as it is merely static relative to itself; a system with two bodies is very simple to solve for, as the bodies orbit around their common center of mass. However, once more than two bodies are introduced, the mathematical calculations become very complicated. A situation arises where you would have to calculate every gravitational interaction between every pair of objects at every point along its trajectory.
Lagrange, however, wanted to make this simpler. He did so with a simple hypothesis: The trajectory of an object is determined by finding a path that minimizes the action over time. This is found by subtracting the potential energy from the kinetic energy. With this way of thinking, Lagrange re-formulated the classical Newtonian mechanics to give rise to Lagrangian mechanics. With his new system of calculations, Lagrange’s work led him to hypothesize how a third body of negligible mass would orbit around two larger bodies which were already in a near-circular orbit. In a frame of reference that rotates with the larger bodies, he found five specific fixed points where the third body experiences zero net force as it follows the circular orbit of its host bodies (planets). These points were named “Lagrangian points” in Lagrange's honor. It took over a hundred years before his mathematical theory was observed with the discovery of the Trojan asteroids in the 1900s at the Lagrange points of the Sun–Jupiter system.
In the more general case of elliptical orbits, there are no longer stationary points in the same sense: it becomes more of a Lagrangian “area”. The Lagrangian points constructed at each point in time, as in the circular case, form stationary elliptical orbits which are similar to the orbits of the massive bodies. This is due to Newton's second law ($\mathbf{F}=d\mathbf{p}/dt$), where p = mv (p the momentum, m the mass, and v the velocity) is invariant if force and position are scaled by the same factor. A body at a Lagrangian point orbits with the same period as the two massive bodies in the circular case, implying that it has the same ratio of gravitational force to radial distance as they do. This fact is independent of the circularity of the orbits, and it implies that the elliptical orbits traced by the Lagrangian points are solutions of the equation of motion of the third body.
## The Lagrangian points
A diagram showing the five Lagrangian points in a two-body system with one body far more massive than the other (e.g. the Sun and the Earth). In such a system, L3–L5 will appear to share the secondary's orbit, although in fact they are situated slightly outside it.
The five Lagrangian points are labeled and defined as follows:
### L1
The L1 point lies on the line defined by the two large masses M1 and M2, and between them. It is the most intuitively understood of the Lagrangian points: the one where the gravitational attraction of M2 partially cancels M1 gravitational attraction.
Example: An object which orbits the Sun more closely than the Earth would normally have a shorter orbital period than the Earth, but that ignores the effect of the Earth's own gravitational pull. If the object is directly between the Earth and the Sun, then the effect of the Earth's gravity is to weaken the force pulling the object towards the Sun, and therefore increase the orbital period of the object. The closer to Earth the object is, the greater this effect is. At the L1 point, the orbital period of the object becomes exactly equal to the Earth's orbital period.
The Sun–Earth L1 is ideal for making observations of the Sun. Objects here are never shadowed by the Earth or the Moon. The Solar and Heliospheric Observatory (SOHO) is stationed in a Halo orbit at L1, and the Advanced Composition Explorer (ACE) is in a Lissajous orbit, also at the L1 point. The Earth–Moon L1 allows easy access to lunar and earth orbits with minimal change in velocity and would be ideal for a half-way manned space station intended to help transport cargo and personnel to the Moon and back.
### L2
A diagram showing the Sun–Earth L2 point, which lies well beyond the Moon's orbit around the Earth.
The L2 point lies on the line defined by the two large masses, beyond the smaller of the two. Here, the gravitational forces of the two large masses balance the centrifugal force on the smaller mass.
Example: On the side of the Earth away from the Sun, the orbital period of an object would normally be greater than that of the Earth. The extra pull of the Earth's gravity decreases the orbital period of the object, and at the L2 point that orbital period becomes equal to the Earth's.
The Sun–Earth L2 is a good spot for space-based observatories. Because an object around L2 will maintain the same orientation with respect to the Sun and Earth, shielding and calibration are much simpler. It is, however, slightly beyond the reach of Earth's umbra, so solar radiation is not completely blocked. The Wilkinson Microwave Anisotropy Probe is already in orbit around the Sun–Earth L2. The Planck satellite, Herschel Space Observatory, Gaia probe, and James Webb Space Telescope will be placed at the Sun–Earth L2. Earth–Moon L2 would be a good location for a communications satellite covering the Moon's far side.
If the mass of the smaller object (M2) is much smaller than the mass of the larger object (M1) then L1 and L2 are at approximately equal distances r from the smaller object, equal to the radius of the Hill sphere, given by:
$r \approx R \sqrt[3]{\frac{M_2}{3 M_1}}$
where R is the distance between the two bodies.
This distance can be described as being such that the orbital period, corresponding to a circular orbit with this distance as radius around M2 in the absence of M1, is that of M2 around M1, divided by $\sqrt{3}\approx 1.73$.
Examples:
• Sun and Earth: 1,500,000 km from the Earth
• Earth and Moon: 61,500 km from the Moon
### L3
The L3 point lies on the line defined by the two large masses, beyond the larger of the two.
Example: L3 in the Sun–Earth system exists on the opposite side of the Sun, a little outside the Earth's orbit but slightly closer to the Sun than the Earth is. (This apparent contradiction is because the Sun is also affected by the Earth's gravity, and so orbits around the two bodies' barycenter, which is however well inside the body of the Sun.) At the L3 point, the combined pull of the Earth and Sun again causes the object to orbit with the same period as the Earth.
The Sun–Earth L3 point was a popular place to put a "Counter-Earth" in pulp science fiction and comic books — though of course, once space based observation was possible via satellites and probes, it was shown to hold no such object. Actually, the Sun–Earth L3 is highly unstable, because the gravitational forces of the other planets outweigh that of the Earth (Venus, for example, comes within 0.3 AU of L3 every 20 months).
### L4 and L5
Gravitational accelerations at L4.
The L4 and L5 points lie at the third corners of the two equilateral triangles in the plane of orbit whose common base is the line between the centers of the two masses, such that the point lies behind (L5) or ahead of (L4) the smaller mass with regard to its orbit around the larger mass.
The reason these points are in balance is that, at L4 and L5, the distances to the two masses are equal. Accordingly, the gravitational forces from the two massive bodies are in the same ratio as the masses of the two bodies, and so the resultant force acts through the barycenter of the system; additionally, the geometry of the triangle ensures that the resultant acceleration is to the distance from the barycenter in the same ratio as for the two massive bodies. The barycenter being both the center of mass and center of rotation of the system, this resultant force is exactly that required to keep a body at the Lagrange point in orbital equilibrium with the rest of the system. (Indeed, the third body need not have negligible mass; the general triangular configuration was discovered by Lagrange in work on the 3-body problem.)
L4 and L5 are sometimes called triangular Lagrange points or Trojan points. The name Trojan points comes from the Trojan asteroids at the Sun–Jupiter L4 and L5 points, which themselves are named after characters from Homer's Iliad (the legendary siege of Troy). Asteroids at the L4 point, which leads Jupiter, are referred to as the 'Greek camp', while at the L5 point they are referred to as the 'Trojan camp'. These asteroids are (largely) named after characters from the respective sides of the Trojan War.
Examples:
• The Sun–Earth L4 and L5 points lie 60° ahead of and 60° behind the Earth as it orbits the Sun. They contain interplanetary dust.
• The Earth–Moon L4 and L5 points lie 60° ahead of and 60° behind the Moon as it orbits the Earth. They may contain interplanetary dust in what is called Kordylewski clouds.
• The Sun–Jupiter L4 and L5 points are occupied by the Trojan asteroids.
• Neptune has Trojan Kuiper Belt Objects at its L4 and L5 points.
• Saturn's moon Tethys has two much smaller satellites at its L4 and L5 points named Telesto and Calypso, respectively.
• Saturn's moon Dione has smaller moons Helene and Polydeuces at its L4 and L5 points, respectively.
• One version of the giant impact hypothesis suggests that an object named Theia formed at L4 or L5 and crashed into the Earth after its orbit destabilized, forming the moon.
## Stability
The first three Lagrangian points are technically stable only in the plane perpendicular to the line between the two bodies. This can be seen most easily by considering the L1 point. A test mass displaced perpendicularly from the central line would feel a force pulling it back towards the equilibrium point. This is because the lateral components of the two masses' gravity would add to produce this force, whereas the components along the axis between them would balance out. However, if an object located at the L1 point drifted closer to one of the masses, the gravitational attraction it felt from that mass would be greater, and it would be pulled closer. (The pattern is very similar to that of tidal forces.)
Although the L1, L2, and L3 points are nominally unstable, it turns out that it is possible to find stable periodic orbits around these points, at least in the restricted three-body problem. These perfectly periodic orbits, referred to as "halo" orbits, do not exist in a full n-body dynamical system such as the solar system. However, quasi-periodic (i.e. bounded but not precisely repeating) orbits following Lissajous curve trajectories do exist in the n-body system. These quasi-periodic Lissajous orbits are what all Lagrangian point missions to date have used. Although they are not perfectly stable, a relatively modest effort at station keeping can allow a spacecraft to stay in a desired Lissajous orbit for an extended period of time. It also turns out that, at least in the case of Sun–Earth L1 missions, it is actually preferable to place the spacecraft in a large amplitude (100,000–200,000 km) Lissajous orbit, instead of having it sit at the Lagrangian point, because this keeps the spacecraft off the direct Sun–Earth line, thereby reducing the impact of solar interference on the Earth–spacecraft communications links. Another interesting and useful property of the collinear Lagrangian points and their associated Lissajous orbits is that they serve as "gateways" to control the chaotic trajectories of the Interplanetary Transport Network.
In contrast to the collinear Lagrangian points, the triangular points (L4 and L5) are stable equilibria (cf. attractor), provided that the ratio of M1/M2 is greater than 24.96. This is the case for the Sun–Earth and, by a smaller margin, the Earth–Moon systems. When a body at these points is perturbed, it moves away from the point, but the Coriolis effect bends the object's path into a stable, kidney bean‐shaped orbit around the point (as seen in the rotating frame of reference). However, in the Earth–Moon case, the problem of stability is greatly complicated by the appreciable solar gravitational influence.
## Intuitive explanation
This section non-mathematically (intuitively) explains the five Lagrangian points using the Earth–Moon system.
Lagrangian points L2 through L5 only exist in rotating systems, as in the monthly orbiting of the Moon about the Earth. At these points, an outward (fictitious, as explained below) centrifugal force is balanced by the attractive gravitational forces of the Moon and Earth.
Imagine a person using his hand to spin a stone at the end of a string. The string provides a tension force that continuously accelerates the stone towards the center. To an ant standing on the stone, however, it seems as if there is a force trying to fling him directly outward from the center. This apparent or fictitious force is called the centrifugal force. This same effect is present in the Earth–Moon system, where the role of the string is played by the summed (or net) effect of the two attractive gravities, and the stone is an asteroid or a spacecraft. The Earth–Moon system rotates about its combined center of mass, or barycenter. Because the Earth is much heavier than the Moon, this point is located within the Earth (about 1700 km below the surface). Any object gravitationally held by the rotating Earth–Moon system will sense a centrifugal force directed away from the barycenter, in the same way as does the ant on the stone.
Unlike the other Lagrangian points, L1 would exist even in a non-rotating (static or inertial) system. Rotation slightly pushes L1 away from the (lighter) Moon towards the (heavier) Earth. L1 is slightly unstable (see stability above) because drifting towards the Moon or Earth increases one gravitational attraction while decreasing the other, causing more drift.
At Lagrangian points L2, L3, L4, and L5, a satellite feels an outward centrifugal force, away from the barycenter, that exactly balances the attractive gravity of the Earth and Moon. L2 and L3 are slightly unstable because small changes in satellite position more strongly affect gravity than the balancing centrifugal force. Stability at L4 and L5 depends crucially on the satellite being pulled in three different directions, namely the outward centrifugal force away from the barycenter, balancing the inward gravitational forces towards the Moon and Earth.
The easiest way to understand the stability is that L1, and L2, and L3 positions are stable, but stable like a ball balanced on a pin. A soft breeze will toss it out of equilibrium. But the L4, and L5 positions are stable more like a ball at the bottom of a bowl. Small perturbations will move it out of place, but it will drift back to the bottom.
## Lagrangian point missions
The Lagrangian point orbits have unique characteristics that have made them a good choice for performing some kinds of missions. These missions generally orbit the points rather than occupy them directly.
### Past and present missions
Mission Lagrangian point Agency Status
Advanced Composition Explorer (ACE) Sun-Earth L1 NASA Operational
Solar and Heliospheric Observatory (SOHO) Sun-Earth L1 ESA, NASA Operational
WIND Sun-Earth L1 NASA Operational
Genesis Sun-Earth L1 NASA Mission ended, left L1 point
International Sun/Earth Explorer 3 (ISEE-3) Sun-Earth L1 NASA Original mission ended, left L1 point
Wilkinson Microwave Anisotropy Probe (WMAP) Sun-Earth L2 NASA Operational
SMART-1 Moon-Earth L1 (flyby) ESA Mission ended, deliberately crashed into moon
STEREO A & B Sun-Earth L4 & L5 NASA Launched 2006; passes through L4 and L5 points respectively, but does not actually orbit them.
New Horizons Sun-Neptune L5 (flyby) NASA Launched; scheduled to arrive August 1, 2014
Herschel and Planck Space Observatories Sun-Earth L2 ESA Launched 14 May 2009, ETA July 2009
### Future and proposed missions
Mission Lagrangian point Agency Status
Deep Space Climate Observatory Sun-Earth L1 NASA On hold
Solar-C Sun-Earth L1 Japan Aerospace Exploration Agency Possible mission after 2010
James Webb Space Telescope Sun-Earth L2 NASA, ESA, Canadian Space Agency Scheduled to launch in June 2013 or later
Communication satellite covering the far side of the Moon Earth–Moon L2 NASA Proposed in 1968[9]
Space colonization and manufacturing Earth-Moon L4 or L5 L5 Society Proposed in 1974
Solar shade Sun-Earth L1 - Various proposals
## Natural examples
In the Sun–Jupiter system several thousand asteroids, collectively referred to as Trojan asteroids, are in orbits around the Sun–Jupiter L4 and L5 points. Recent observations suggest that the Sun–Neptune L4 and L5 points, known as the Neptune Trojans, may be very thickly populated, containing large bodies an order of magnitude more numerous than the Jupiter Trojans. Other bodies can be found in the Sun–Mars and Saturn–Saturnian satellite systems. There are no known large bodies in the Sun–Earth system's Trojan points, but clouds of dust surrounding the L4 and L5 points were discovered in the 1950s. Clouds of dust, called Kordylewski clouds, even fainter than the notoriously weak gegenschein, may also be present in the L4 and L5 of the Earth–Moon system.
The Saturnian moon Tethys has two smaller moons in its L4 and L5 points, Telesto and Calypso. The Saturnian moon Dione also has two Lagrangian co-orbitals, Helene at its L4 point and Polydeuces at L5. The moons wander azimuthally about the Lagrangian points, with Polydeuces describing the largest deviations, moving up to 32 degrees away from the Saturn–Dione L5 point. Tethys and Dione are hundreds of times more massive than their "escorts" (see the moons' articles for exact diameter figures; masses are not known in several cases), and Saturn is far more massive still, which makes the overall system stable.
### Other co-orbitals
The Earth's companion object 3753 Cruithne is in a relationship with the Earth which is somewhat Trojan-like, but different from a true Trojan. This asteroid occupies one of two regular solar orbits, one of them slightly smaller and faster than the Earth's orbit, and the other slightly larger and slower. The asteroid periodically alternates between these two orbits due to close encounters with Earth. When the asteroid is in the smaller, faster orbit and approaches the Earth, it gains orbital energy from the Earth and moves up into the larger, slower orbit. It then falls farther and farther behind the Earth, and eventually Earth approaches it from the other direction. Then the asteroid gives up orbital energy to the Earth, and drops back into the smaller orbit, thus beginning the cycle anew. The cycle has no noticeable impact on the length of the year, because Earth's mass is over 20 billion (2 × 10) times more than 3753 Cruithne.
Epimetheus and Janus, satellites of Saturn, have a similar relationship, though they are of similar masses and so actually exchange orbits with each other periodically. (Janus is roughly 4 times more massive but still light enough for its orbit to be altered.) Another similar configuration is known as orbital resonance, in which orbiting bodies tend to have periods of a simple integer ratio, due to their interaction.
## In fiction
Lagrange points are often mentioned in science fiction (most often hard science fiction), but are rarely used as a plot device because Lagrange points are unfamiliar outside of the scientific or space-enthusiast community.
#### L1
• In Arthur Clarke and Stephen Baxter's novel Sunstorm, the L1 point plays a crucial role in the building of a shield that has the purpose of saving Earth from a storm of energy from the Sun.
• The planet on which Pitch Black is set receives continual daylight: an orrery depicts it at the apparent L1 point between one star and a pair of tightly orbiting stars, receiving periodic eclipses from a pair of gas giants occupying a wider orbit about L1 in the same plane.
• In Peter F. Hamilton's Night's Dawn Trilogy, a ZTT jump drive cannot be used in a strong gravitational field. In the first book of the trilogy, The Reality Dysfunction, the main characters cannot escape from a gas giant's gravity well before their pursuers catch up with them. Instead, they race to the Lagrange point between the gas giant and one of its moons in order to activate their drive. Successful execution of this untried and reckless maneuver gains captain Joshua Calvert the nickname "Lagrange" Calvert. In the second book The Neutronium Alchemist, a visit is paid to the supposed home planet of the Kiint, Jobis, which features three moons orbiting the Lagrange One point, rotating around a common center.
• Robert L. Forward's novel Rocheworld concerns a double planet, called Roche and Eau, close enough to share an atmosphere. At certain times water flows through the L1 point from Eau to Roche.
#### L2
• In the TV series Quatermass II, the hostile aliens live on a small asteroid "no more than half a mile across" at a "theoretical point of equilibrium" on the dark side of the Earth, although neither L2 nor Lagrange are mentioned by name (the term "Bieber Variation" is used instead).
• In the manga series Battle Angel Alita: Last Order, the ex-colony ship turned space station Leviathan 1 is at the L2 point in the Earth/Moon system.
• In John Varley's book Wizard, a religious group called the Coven set up a habitat at L2 to make themselves as remote as possible from the earth. L2 later slowly deteriorates into the space version of an unorganized shantytown as anyone with enough cash can set up a home there. "L2 became known as Sargasso Point to the pilots who carefully avoided it; those who had to travel through it called it the Pinball Machine, and they didn't smile."
• In Gundam 00 Lagrange-2 of the Earth-Moon system is the location of Veda.
#### L3
• In the third season of the TV series Lexx, the planets Fire and Water are found to reside in Earth's L3 point.
• John Norman's Gor series takes place on a counter earth.
• In Mobile Suit Gundam 00, Celestial Being have established a base at Lagrange-3 of the Earth-Moon system. Here, they can make repairs as well as introduce new units.
• In Journey to the Far Side of the Sun, astronauts from earth find a mirror-image copy of the earth exactly on the opposite side of the sun.
• In the first season episode of Space 1999 "The Last Enemy" the crew of moonbase Alpha encounter two planets "Betha" and "Delta" in a typical "Lagrange L3" orbit.
#### L4
• In Ben Bova's novel Colony, Island One is a space colony located at the Earth-Moon L4. This is because the colony's founder, Cyrus Cobb, found that L4 gave a better view of the moon than L5.
#### L5
• In William Gibson's novel Neuromancer, much of the action takes place in the L5 "archipelago", the location of many space stations.
• The space station Babylon 5 is described to be located "at the L-5 point in a binary star system between a moon and a barren, lifeless planet."
• In Dan Simmons's novel The Rise of Endymion, the headquarters of the Pax Mercantilus is located at the L5 point of the planet Pacem, where CEO Kenzo Isozaki has a splendid view of the planet.
• In the novel Nature's End by Whitley Strieber and James Kunetka, a fictional future Russian Space Agency has established a colony at the L5 point in the Earth-Moon system appropriately named the "L5 Colony".
#### Unspecified Lagrange points
• In the Starfire strategy game and the series of military science-fiction novels based on it, written by David Weber and Steve White, the warp points which allow starships to transit between solar systems without moving at faster-than-light speeds typically form at the Lagrange points.
• Lagrange points are famously mentioned in Arthur C. Clarke's novel 2010: Odyssey Two and the subsequent science fiction film 2010, where the Discovery spacecraft is located on a Lagrange point. The movie expands on this, claiming that Discovery is located at a point between Io and Jupiter, which would place it in the L1 point of the Jupiter–Io system.
• In Robert Forward's Rocheworld, the locations for Lagrange points around a binary planet are discussed in contrast to typical system.
• In the Battletech game series, a star's Nadir and Zenith are the standard hyperspace jump points for most interstellar spacecraft. Lagrange points (only the L1 point) are sometimes used to enter a system closer to planets, almost always for small-scale military or pirate operations due to the risk of catastrophic misjumps.
• In the Halo novels, the Lagrange points are the only places where a human ship can safely make a slipspace jump. In Halo, the namesake ring-world also occupies a Lagrange point between fictional planet Threshold, and its moon, Basis.
• In the PC video game Star Wars: X-Wing, Lagrange points are mentioned in the briefings of some missions that revolve around attacking objects placed at them.
• In the sci-fi series Stargate Atlantis, there was a defensive satellite located at a Lagrangian point in the solar system in which Atlantis was located.
• In 1991, Konami released a science fiction RPG for the NES in Japan called Lagrange Point.
• In the Robotech television series, an effect called an Orbital Warp Blast is created when a spaceship creates "a phenomenon known as the molecular vacuum" at a fictional "Lagrange Point 6, approximately 20,000 kilometers from Mars" (where one does not exist in the real world).
• In The Monkeys Thought 'Twas All In Fun by Orson Scott Card, a structure called the Trojan Object appears at L4 or L5.
• In a parody of the science fiction comic Freefall, a character refers to a satellite bar located in "the Lagrange point" so that it's always Happy hour there. He then heads for the bar promising to be back before sunset (which never happens).
• Ken MacLeod's novel The Star Fraction mentions a collection of human habitats at the Earth-Sun Lagrange point, with semi-permanent residents. Implicitly, it is the L1 point which is referred to.
#### Related concepts
In Larry Niven's novel Ringworld, the Puppeteers' "Fleet of Worlds" is arranged in a configuration (5 planets spaced at the points of a pentagon) called a Klemperer Rosette (misspelled "Kemplerer" in the novel). In actual fact, while it is an extension of the Lagrange concept to a special case N-body problem, and on the surface appears to be an extension of the L4 and L5 orbital mechanics, its stability is more akin to the L1, L2, and L3 positions. Considerable energy expenditure would be required to maintain it over time.
## Notes and references
Published - July 2009
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https://jp.maplesoft.com/support/help/maplesim/view.aspx?path=EssayTools/BuildScoreModel
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BuildScoreModel - Maple Help
Home : Support : Online Help : Education : EssayTools : BuildScoreModel
EssayTools
BuildScoreModel
grade essays based on training data
Score
grade essays based on training data
Calling Sequence BuildScoreModel( essays, scores ) Score( essay, model )
Parameters
essays - array of strings scores - array of numeric grades questionText - (optional) string essay - string model - module returned by BuildScoreModel
Description
• The BuildScoreModel command takes existing essays with assigned grades and returns a module that can be used by the Score command. The Score command gives a rating for a new essay based on attributes of previously scored essays stored in built scoring model.
• The reliability of the Score commands depends greatly on the amount of training data used to build the model. At least 150 scored essays are required to start getting minimum performance (on the order of a 50% - 70% correlation with human-graded essays). Larger sets on the order of 300 - 800 training essays are preferable and have been shown to score QuadraticWeightedKappa values of better than .80 compared to human grading.
• The reliability of the score also depends on many other factors including the length of the expected answer (longer is better), and the nature of the question.
• Questions can be wide-open with no set expected answer. An open-ended question like, "tell a humorous story" has no one expected answer or pattern of keywords that must be common between answers. In this case the style of writing becomes more important. The results of computer scoring of such questions has proven to have a high correlation with human scoring.
• Generally computer scoring is used in conjunction with human scoring. A set of essays will be scored by a human grader and the computer. Any essays that receive scores that disagree by more than one or two points are then re-scored by an independent human grader. Computer scoring has also been found useful for immediate feedback in homework and practice.
• The text of the question can optionally be added to the model using the questionText = option. It is recommended that this option be used.
• This function is part of the EssayTools package, so it can be used in the short form BuildScoreModel(..) only after executing the command with(EssayTools). However, it can always be accessed through the long form of the command by using EssayTools[BuildScoreModel](..).
Examples
> $\mathrm{Question}≔"What is Archimedes Principle?":$
> $\mathrm{Answers}≔\left["Archimedes\text{'} principle is a law of physics stating that the upward force \left(buoyancy\right) exerted on a body immersed in a fluid is equal to the weight of the amount of fluid the body displaces.","Archimedes\text{'} principle says that the magnitude of the buoyancy force is also equivalent to the weight of the displaced fluid.","Archimedes\text{'} principle states that a body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid.","Archemedes ran through town shouting Eureka because he noticed something about the water in his bath.","Archimedes principle says water weighs more than a block of gold.","Archimedes\text{'} principal is the law that states that a boyancy force is equal to a girlancy force.","Archimedes principle says that a block of gold will displace a matching volume of water.","Archimedes principle is a law that says a boyancy force is equal to the weight of the displaced water","Archimedes principle was discovered when King Hiero suspected that his new crown was not pure gold. Archimedes figured out how to test for a fake. He compared the weight of the crown with the weight of displaced water."\right]:$
> $\mathrm{Scores}≔\left[10,10,10,3,0,0,4,7,6\right]:$
> $\mathrm{with}\left(\mathrm{EssayTools}\right):$
> $\mathrm{model}≔\mathrm{BuildScoreModel}\left(\mathrm{Answers},\mathrm{Scores},\mathrm{questionText}=\mathrm{Question}\right):$
> $\mathrm{Score}\left("I don\text{'}t know.",\mathrm{model}\right)$
${0}$ (1)
> $\mathrm{Score}\left("Archimedes\text{'} principle is about buoyancy.",\mathrm{model}\right)$
${3}$ (2)
> $\mathrm{Score}\left("Archimedes\text{'} principle is a law that equates the force of buoyancy and the amount of displaced fluid.",\mathrm{model}\right)$
${6}$ (3)
> $\mathrm{Score}\left("Nothing happened. The fish just moved away slowly and the old man could not raise him an inch. His line was strong and made for heavy fish and he held it against his hack until it was so taut that beads of water were jumping from it. Then it began to make a slow hissing sound in the water and he still held it, bracing himself against the thwart and leaning back against the pull. The boat began to move slowly off toward the north-west.",\mathrm{model}\right)$
${1}$ (4)
References
Butcher, Philip G. and Jordan, Sally E. (2010). A comparison of human and computer marking of short free-text student responses. Computers and Education, 55(2), pp. 489-499
Kakkonen, T., Myller, N., Sutinen, E., and Timonen, J. (2008). Comparison of Dimension Reduction Methods for Automated Essay Grading. Educational Technology & Society, 11(3), 275-288
Kaplan, Randy M., Wolff, Susanne E., Burstein, Jill C., Lu, Chi, Rock, Donald A., and Kaplan, Bruce A. (1998), Scoring Essays Automatically Using Surface Features, GRE Board Professional Report No. 94-21P
Miltsakaki, Eleni and Kukich, Karen, Automated Evaluation of Coherence in Student Essays
Shermis, Mark D. and Hamner, Ben, (2012) Contrasting State-of-the-Art Automated Scoring of Essays: Analysis
Compatibility
• The EssayTools[BuildScoreModel] and EssayTools[Score] commands were introduced in Maple 17.
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http://mathonline.wikidot.com/dense-sets-in-finite-topological-products
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Dense Sets in Finite Topological Products
# Dense Sets in Finite Topological Products
Consider a finite collection of topological spaces $\{ X_1, X_2, ..., X_n \}$. If $A_i \subseteq X_i$ are dense in $X_i$ for all $i \in \{1, 2, ..., n \}$, then what can we say about the product $\displaystyle{\prod_{i=1}^{n} A_i}$?
Conversely, if $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$, what can we say about each individual set $A_i$ in $X_i$?
The following theorem gives us the desired answer. $A_i \subseteq X_i$ is dense in $X_i$ for all $i \in \{1, 2, ..., n \}$ if and only if $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$.
Theorem 1: Let $\{ X_1, X_2, ..., X_n \}$ be a finite collection of topological spaces and let $A_i \subseteq X_i$ for all $i \in \{ 1, 2, ..., n \}$. Then $A_i$ is dense in $X_i$ for all $i \in \{ 1, 2, ..., n \}$ if and only if $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$.
• Proof: $\Rightarrow$ Suppose that $A_i$ is dense in $X_i$ for all $i \in \{1, 2, ..., n \}$. Let $\displaystyle{U = \prod_{i=1}^{n} U_i}$ be any open set in $\displaystyle{\prod_{i=1}^{n} X_i}$. Then $U_i$ is open in $X_i$ for all $i \in \{ 1, 2, ..., n \}$. So since $A_i$ is dense in $X_i$ we have that for all $i$ that:
(1)
\begin{align} \quad A_i \cap U_i \neq \emptyset \end{align}
• So take $x_i \in A_i \cap U_i$. Then $\mathbf{x} = (x_1, x_2, ..., x_n)$ is such that:
(2)
\begin{align} \quad \mathbf{x} \in \left ( \prod_{i=1}^{n} A_i \right ) \cap \left ( \prod_{i=1}^{n} U_i \right ) \end{align}
• Thus $\displaystyle{\left ( \prod_{i=1}^{n} A_i \right ) \cap \left ( \prod_{i=1}^{n} U_i \right ) \neq \emptyset}$ for all open sets $\displaystyle{U = \prod_{i=1}^{n} U_i}$ in $\displaystyle{\prod_{i=1}^{n} X_i}$ which shows that $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$.
• $\Leftarrow$ Suppose that $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$.
• Consider the set $A_i$ and let $U_i$ be any open set in $X_i$. Let:
(3)
\begin{align} \quad U = X_1 \times X_2 \times ... \times X_{i-1} \times U_i \times X_{i+1}, \times ... \times X_n \end{align}
• Then $U$ is an open set in $\displaystyle{\prod_{i=1}^{n} X_i}$. Since $\displaystyle{\prod_{i=1}^{n} A_i}$ is dense in $\displaystyle{\prod_{i=1}^{n} X_i}$ we have that:
(4)
\begin{align} \quad \left ( \prod_{i=1}^{n} A_i \right ) \cap U & \neq \emptyset \\ \quad \left ( A_1 \times A_2 \times ... \times A_n \right ) \cap \left (X_1 \times X_2 \times ... \times X_{i-1} \times U_i \times X_{i+1} \times ... \times X_n \right ) & \neq \emptyset \\ \quad ( A_1 \cap X_1) \times (A_2 \cap X_2) \times ... \times (A_{i-1} \cap X_{i-1}) \times (A_i \cap U_i) \times (A_{i+1} \cap X_{i+1}) \times ... \times (A_n \cap X_n) & \neq \emptyset \\ \quad A_1 \times A_2 \times ... \times A_{i-1} \times (A_i \cap U_i) \times A_{i+1} \times ... \times A_n & \neq \emptyset \end{align}
• This shows that $A_i \cap U_i \neq \emptyset$.
• So for all $i \in \{ 1, 2, ..., n \}$ we have that $A_i$ is dense in $X_i$. $\blacksquare$
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http://www.edintone.com/catablog-items/marriott-edmund-edward-northampton/
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1966 Exhibition: Mid 19th Cent.
Philips 1853
Link to external resource: .
Return to the Clock and Watchmakers index
Sorry, the comment form is closed at this time.
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https://proofwiki.org/wiki/Definition:Beta_Function/Historical_Note
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# Definition:Beta Function/Historical Note
The beta function $\Beta \left({x, y}\right)$ was discovered by Leonhard Paul Euler.
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http://mathematica.stackexchange.com/questions/1044/how-to-write-into-multiple-files?answertab=oldest
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How to Write into multiple files?
Note: this is fixed in version 9.
I want to put expressions into multiple files simultaneously, with the following code:
tex1 = OpenWrite["test1.txt"];
tex2 = OpenWrite["test2.txt"];
Write[{tex1, tex2}, "anything"]
Close[tex1];
Close[tex2];
Why is test2.txt empty? Why does it work correctly with WriteString instead of Write? Now of course I can always Map the Write statements over streams, or just go with WriteString, but since it would be convenient to use a list as Write's first argument I did post this issue. Is it a bug?
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@ArnoudBuzing, what do you think of this? – rcollyer Jan 31 '12 at 15:42
It seems like a possible bug. I will report it. – Arnoud Buzing Feb 1 '12 at 0:37
@ArnoudBuzing István has indicated that this bug has been unfixed for at least 5 years: groups.google.com/group/comp.soft-sys.math.mathematica/… – Mike Honeychurch Feb 1 '12 at 1:30
@ArnoudBuzing: Thanks for reporting it. This raises another meta question in me... – István Zachar Feb 1 '12 at 9:33
This is a bug and fixed in the development version. Thanks for pointing it out.
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According to the docs, both Write and WriteString should accept an "output channel," which is just a list of streams. On my system (v.8 on MacOS), Write behaves the same way as on your system when outputting anything, but WriteString behaves as expected.
Similarly, this
Write[{tex1, tex2}, 3, 4];
also misbehaves in the same manner. So, the issue isn't limited to string output.
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https://en.m.wikipedia.org/wiki/Multivariate_analysis_of_variance
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# Multivariate analysis of variance
In statistics, multivariate analysis of variance (MANOVA) is a procedure for comparing multivariate sample means. As a multivariate procedure, it is used when there are two or more dependent variables,[1] and is typically followed by significance tests involving individual dependent variables separately. It helps to answer:[2]
1. Do changes in the independent variable(s) have significant effects on the dependent variables?
2. What are the relationships among the dependent variables?
3. What are the relationships among the independent variables?
## Relationship with ANOVA
MANOVA is a generalized form of univariate analysis of variance (ANOVA),[1] although, unlike univariate ANOVA, it uses the covariance between outcome variables in testing the statistical significance of the mean differences.
Where sums of squares appear in univariate analysis of variance, in multivariate analysis of variance certain positive-definite matrices appear. The diagonal entries are the same kinds of sums of squares that appear in univariate ANOVA. The off-diagonal entries are corresponding sums of products. Under normality assumptions about error distributions, the counterpart of the sum of squares due to error has a Wishart distribution.
MANOVA is based on the product of model variance matrix, ${\displaystyle \Sigma _{model}}$ and inverse of the error variance matrix, ${\displaystyle \Sigma _{res}^{-1}}$ , or ${\displaystyle A=\Sigma _{model}\times \Sigma _{res}^{-1}}$ . The hypothesis that ${\displaystyle \Sigma _{model}=\Sigma _{residual}}$ implies that the product ${\displaystyle A\sim I}$ .[3] Invariance considerations imply the MANOVA statistic should be a measure of magnitude of the singular value decomposition of this matrix product, but there is no unique choice owing to the multi-dimensional nature of the alternative hypothesis.
The most common[4][5] statistics are summaries based on the roots (or eigenvalues) ${\displaystyle \lambda _{p}}$ of the ${\displaystyle A}$ matrix:
• Samuel Stanley Wilks' ${\displaystyle \Lambda _{Wilks}=\prod _{1...p}(1/(1+\lambda _{p}))=\det(I+A)^{-1}=\det(\Sigma _{res})/\det(\Sigma _{res}+\Sigma _{model})}$ distributed as lambda (Λ)
• the Pillai-M. S. Bartlett trace, ${\displaystyle \Lambda _{Pillai}=\sum _{1...p}(\lambda _{p}/(1+\lambda _{p}))=\mathrm {tr} ((I+A)^{-1})}$ [6]
• the Lawley-Hotelling trace, ${\displaystyle \Lambda _{LH}=\sum _{1...p}(\lambda _{p})=\mathrm {tr} (A)}$
• Roy's greatest root (also called Roy's largest root), ${\displaystyle \Lambda _{Roy}=max_{p}(\lambda _{p})=\|A\|_{\infty }}$
Discussion continues over the merits of each,[1] although the greatest root leads only to a bound on significance which is not generally of practical interest. A further complication is that, except for the Roy's greatest root, the distribution of these statistics under the null hypothesis is not straightforward and can only be approximated except in a few low-dimensional cases.[7] An algorithm for the distribution of the Roy's largest root under the null hypothesis was derived in [8] while the distribution under the alternative is studied in.[9]
The best-known approximation for Wilks' lambda was derived by C. R. Rao.
In the case of two groups, all the statistics are equivalent and the test reduces to Hotelling's T-square.
## Correlation of dependent variables
MANOVA's power is affected by the correlations of the dependent variables and by the effect sizes associated with those variables. For example, when there are two groups and two dependent variables, MANOVA's power is lowest when the correlation equals the ratio of the smaller to the larger standardized effect size.[10]
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https://diabetesjournals.org/care/article/46/Supplement_1/S140/148057/9-Pharmacologic-Approaches-to-Glycemic-Treatment
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The American Diabetes Association (ADA) “Standards of Care in Diabetes” includes the ADA’s current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA’s clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.
Recommendations
• 9.1 Most individuals with type 1 diabetes should be treated with multiple daily injections of prandial and basal insulin, or continuous subcutaneous insulin infusion. A
• 9.2 Most individuals with type 1 diabetes should use rapid-acting insulin analogs to reduce hypoglycemia risk. A
• 9.3 Individuals with type 1 diabetes should receive education on how to match mealtime insulin doses to carbohydrate intake, fat and protein content, and anticipated physical activity. B
Insulin Therapy
Because the hallmark of type 1 diabetes is absent or near-absent β-cell function, insulin treatment is essential for individuals with type 1 diabetes. In addition to hyperglycemia, insulinopenia can contribute to other metabolic disturbances like hypertriglyceridemia and ketoacidosis as well as tissue catabolism that can be life threatening. Severe metabolic decompensation can be, and was, mostly prevented with once- or twice-daily injections for the six or seven decades after the discovery of insulin. However, over the past three decades, evidence has accumulated supporting more intensive insulin replacement, using multiple daily injections of insulin or continuous subcutaneous administration through an insulin pump, as providing the best combination of effectiveness and safety for people with type 1 diabetes. The Diabetes Control and Complications Trial (DCCT) demonstrated that intensive therapy with multiple daily injections or continuous subcutaneous insulin infusion (CSII) reduced A1C and was associated with improved long-term outcomes (13). The study was carried out with short-acting (regular) and intermediate-acting (NPH) human insulins. In this landmark trial, lower A1C with intensive control (7%) led to ∼50% reductions in microvascular complications over 6 years of treatment. However, intensive therapy was associated with a higher rate of severe hypoglycemia than conventional treatment (62 compared with 19 episodes per 100 patient-years of therapy). Follow-up of subjects from the DCCT more than 10 years after the active treatment component of the study demonstrated fewer macrovascular as well as fewer microvascular complications in the group that received intensive treatment (2,4).
Insulin replacement regimens typically consist of basal insulin, mealtime insulin, and correction insulin (5). Basal insulin includes NPH insulin, long-acting insulin analogs, and continuous delivery of rapid-acting insulin via an insulin pump. Basal insulin analogs have longer duration of action with flatter, more constant plasma concentrations and activity profiles than NPH insulin; rapid-acting analogs (RAA) have a quicker onset and peak and shorter duration of action than regular human insulin. In people with type 1 diabetes, treatment with analog insulins is associated with less hypoglycemia and weight gain as well as lower A1C compared with human insulins (68). More recently, two injectable insulin formulations with enhanced rapid-action profiles have been introduced. Inhaled human insulin has a rapid peak and shortened duration of action compared with RAA and may cause less hypoglycemia and weight gain (9) (see also subsection alternative insulin routes in pharmacologic therapy for adults with type 2 diabetes), and faster-acting insulin aspart and insulin lispro-aabc may reduce prandial excursions better than RAA (1012). In addition, longer-acting basal analogs (U-300 glargine or degludec) may confer a lower hypoglycemia risk compared with U-100 glargine in individuals with type 1 diabetes (13,14). Despite the advantages of insulin analogs in individuals with type 1 diabetes, for some individuals the expense and/or intensity of treatment required for their use is prohibitive. There are multiple approaches to insulin treatment, and the central precept in the management of type 1 diabetes is that some form of insulin be given in a planned regimen tailored to the individual to keep them safe and out of diabetic ketoacidosis and to avoid significant hypoglycemia, with every effort made to reach the individual’s glycemic targets.
Most studies comparing multiple daily injections with CSII have been relatively small and of short duration. However, a systematic review and meta-analysis concluded that CSII via pump therapy has modest advantages for lowering A1C (−0.30% [95% CI −0.58 to −0.02]) and for reducing severe hypoglycemia rates in children and adults (15). However, there is no consensus to guide the choice of injection or pump therapy in a given individual, and research to guide this decision-making is needed (16). The arrival of continuous glucose monitors (CGM) to clinical practice has proven beneficial in people using insulin therapy. Its use is now considered standard of care for most people with type 1 diabetes (5) (see Section 7, “Diabetes Technology”). Reduction of nocturnal hypoglycemia in individuals with type 1 diabetes using insulin pumps with CGM is improved by automatic suspension of insulin delivery at a preset glucose level (1618). When choosing among insulin delivery systems, individual preferences, cost, insulin type and dosing regimen, and self-management capabilities should be considered (see Section 7, “Diabetes Technology”).
The U.S. Food and Drug Administration (FDA) has now approved multiple hybrid closed-loop pump systems (also called automated insulin delivery [AID] systems). The safety and efficacy of hybrid closed-loop systems has been supported in the literature in adolescents and adults with type 1 diabetes (19,20), and evidence suggests that a closed-loop system is superior to sensor-augmented pump therapy for glycemic control and reduction of hypoglycemia over 3 months of comparison in children and adults with type 1 diabetes (21). In the International Diabetes Closed Loop (iDCL) trial, a 6-month trial in people with type 1 diabetes at least 14 years of age, the use of a closed-loop system was associated with a greater percentage of time spent in the target glycemic range, reduced mean glucose and A1C levels, and a lower percentage of time spent in hypoglycemia compared with use of a sensor-augmented pump (22).
Intensive insulin management using a version of CSII and continuous glucose monitoring should be considered in most individuals with type 1 diabetes. AID systems may be considered in individuals with type 1 diabetes who are capable of using the device safely (either by themselves or with a caregiver) in order to improve time in range and reduce A1C and hypoglycemia (22). See Section 7, “Diabetes Technology,” for a full discussion of insulin delivery devices.
In general, individuals with type 1 diabetes require 50% of their daily insulin as basal and 50% as prandial, but this is dependent on a number of factors, including whether the individual consumes lower or higher carbohydrate meals. Total daily insulin requirements can be estimated based on weight, with typical doses ranging from 0.4 to 1.0 units/kg/day. Higher amounts are required during puberty, pregnancy, and medical illness. The American Diabetes Association/JDRF Type 1 Diabetes Sourcebook notes 0.5 units/kg/day as a typical starting dose in individuals with type 1 diabetes who are metabolically stable, with half administered as prandial insulin given to control blood glucose after meals and the other half as basal insulin to control glycemia in the periods between meal absorption (23); this guideline provides detailed information on intensification of therapy to meet individualized needs. In addition, the American Diabetes Association (ADA) position statement “Type 1 Diabetes Management Through the Life Span” provides a thorough overview of type 1 diabetes treatment (24).
Typical multidose regimens for individuals with type 1 diabetes combine premeal use of shorter-acting insulins with a longer-acting formulation. The long-acting basal dose is titrated to regulate overnight and fasting glucose. Postprandial glucose excursions are best controlled by a well-timed injection of prandial insulin. The optimal time to administer prandial insulin varies, based on the pharmacokinetics of the formulation (regular, RAA, inhaled), the premeal blood glucose level, and carbohydrate consumption. Recommendations for prandial insulin dose administration should therefore be individualized. Physiologic insulin secretion varies with glycemia, meal size, meal composition, and tissue demands for glucose. To approach this variability in people using insulin treatment, strategies have evolved to adjust prandial doses based on predicted needs. Thus, education on how to adjust prandial insulin to account for carbohydrate intake, premeal glucose levels, and anticipated activity can be effective and should be offered to most individuals (25,26). For individuals in whom carbohydrate counting is effective, estimates of the fat and protein content of meals can be incorporated into their prandial dosing for added benefit (27) (see Section 5, “Facilitating Positive Health Behaviors and Well-being to Improve Health Outcomes”).
The 2021 ADA/European Association for the Study of Diabetes (EASD) consensus report on the management of type 1 diabetes in adults summarizes different insulin regimens and glucose monitoring strategies in individuals with type 1 diabetes (Fig. 9.1 and Table 9.1 ) (5).
Figure 9.1
Choices of insulin regimens in people with type 1 diabetes. Continuous glucose monitoring improves outcomes with injected or infused insulin and is superior to blood glucose monitoring. Inhaled insulin may be used in place of injectable prandial insulin in the U.S. 1The number of plus signs (+) is an estimate of relative association of the regimen with increased flexibility, lower risk of hypoglycemia, and higher costs between the considered regimens. LAA, long-acting insulin analog; MDI, multiple daily injections; RAA, rapid-acting insulin analog; URAA, ultra-rapid-acting insulin analog. Reprinted from Holt et al. (5).
Figure 9.1
Choices of insulin regimens in people with type 1 diabetes. Continuous glucose monitoring improves outcomes with injected or infused insulin and is superior to blood glucose monitoring. Inhaled insulin may be used in place of injectable prandial insulin in the U.S. 1The number of plus signs (+) is an estimate of relative association of the regimen with increased flexibility, lower risk of hypoglycemia, and higher costs between the considered regimens. LAA, long-acting insulin analog; MDI, multiple daily injections; RAA, rapid-acting insulin analog; URAA, ultra-rapid-acting insulin analog. Reprinted from Holt et al. (5).
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Table 9.1
Examples of subcutaneous insulin regimens
Regimens that more closely mimic normal insulin secretion
Insulin pump therapy (hybrid closed-loop, low-glucose suspend, CGM-augmented open-loop, BGM-augmented open-loop) Basal delivery of URAA or RAA; generally 40–60% of TDD.
Mealtime and correction: URAA or RAA by bolus based on ICR and/or ISF and target glucose, with pre-meal insulin ∼15 min before eating.
Can adjust basal rates for varying insulin sensitivity by time of day, for exercise and for sick days.
Flexibility in meal timing and content.
Pump can deliver insulin in increments of fractions of units.
Potential for integration with CGM for low-glucose suspend or hybrid closed-loop.
TIR % highest and TBR % lowest with: hybrid closed-loop > low-glucose suspend > CGM-augmented open-loop > BGM-augmented open-loop.
Most expensive regimen.
Must continuously wear one or more devices.
Risk of rapid development of ketosis or DKA with interruption of insulin delivery.
Potential reactions to adhesives and site infections.
Most technically complex approach (harder for people with lower numeracy or literacy skills).
Mealtime insulin: if carbohydrate counting is accurate, change ICR if glucose after meal consistently out of target.
Correction insulin: adjust ISF and/or target glucose if correction does not consistently bring glucose into range.
Basal rates: adjust based on overnight, fasting or daytime glucose outside of activity of URAA/RAA bolus.
MDI: LAA + flexible doses of URAA or RAA at meals LAA once daily (insulin detemir or insulin glargine may require twice-daily dosing); generally 50% of TDD.
Mealtime and correction: URAA or RAA based on ICR and/or ISF and target glucose.
Can use pens for all components.
Flexibility in meal timing and content.
Insulin analogs cause less hypoglycemia than human insulins.
At least four daily injections.
Most costly insulins.
Smallest increment of insulin is 1 unit (0.5 unit with some pens).
LAAs may not cover strong dawn phenomenon (rise in glucose in early morning hours) as well as pump therapy.
Mealtime insulin: if carbohydrate counting is accurate, change ICR if glucose after meal consistently out of target.
Correction insulin: adjust ISF and/or target glucose if correction does not consistently bring glucose into range.
LAA: based on overnight or fasting glucose or daytime glucose outside of activity time course, or URAA or RAA injections.
MDI regimens with less flexibility
Four injections daily with fixed doses of N and RAA Pre-breakfast: RAA ∼20% of TDD.
Pre-lunch: RAA ∼10% of TDD.
Pre-dinner: RAA ∼10% of TDD.
Bedtime: N ∼50% of TDD.
May be feasible if unable to carbohydrate count.
All meals have RAA coverage.
N is less expensive than LAAs.
Shorter duration RAA may lead to basal deficit during day; may need twice-daily N.
Greater risk of nocturnal hypoglycemia with N.
Requires relatively consistent mealtimes and carbohydrate intake.
Pre-breakfast RAA: based on BGM after breakfast or before lunch.
Pre-lunch RAA: based on BGM after lunch or before dinner.
Pre-dinner RAA: based on BGM after dinner or at bedtime.
Evening N: based on fasting or overnight BGM.
Four injections daily with fixed doses of N and R Pre-breakfast: R ∼20% of TDD.
Pre-lunch: R ∼10% of TDD.
Pre-dinner: R ∼10% of TDD.
Bedtime: N ∼50% of TDD.
May be feasible if unable to carbohydrate count.
R can be dosed based on ICR and correction.
All meals have R coverage.
Least expensive insulins.
Greater risk of nocturnal hypoglycemia with N.
Greater risk of delayed post-meal hypoglycemia with R.
Requires relatively consistent mealtimes and carbohydrate intake.
R must be injected at least 30 min before meal for better effect.
Pre-breakfast R: based on BGM after breakfast or before lunch.
Pre-lunch R: based on BGM after lunch or before dinner.
Pre-dinner R: based on BGM after dinner or at bedtime.
Evening N: based on fasting or overnight BGM.
Regimens with fewer daily injections
Three injections daily: N+R or N+RAA Pre-breakfast: ∼40% N + ∼15% R or RAA.
Pre-dinner: ∼15% R or RAA.
Bedtime: 30% N.
Morning insulins can be mixed in one syringe.
May be appropriate for those who cannot take injection in middle of day.
Morning N covers lunch to some extent.
Same advantages of RAAs over R.
Least (N+R) or less expensive insulins than MDI with analogs.
Greater risk of nocturnal hypoglycemia with N than LAAs.
Greater risk of delayed post-meal hypoglycemia with R than RAAs.
Requires relatively consistent mealtimes and carbohydrate intake.
Coverage of post-lunch glucose often suboptimal.
R must be injected at least 30 min before meal for better effect.
Morning N: based on pre-dinner BGM.
Morning R: based on pre-lunch BGM.
Morning RAA: based on post-breakfast or pre-lunch BGM.
Pre-dinner R: based on bedtime BGM.
Pre-dinner RAA: based on post-dinner or bedtime BGM.
Evening N: based on fasting BGM.
Twice-daily “split-mixed”: N+R or N+RAA Pre-breakfast: ∼40% N + ∼15% R or RAA.
Pre-dinner: ∼30% N + ∼15% R or RAA.
Least number of injections for people with strong preference for this.
Insulins can be mixed in one syringe.
Least (N+R) or less (N+RAA) expensive insulins vs analogs.
Eliminates need for doses during the day.
Risk of hypoglycemia in afternoon or middle of night from N.
Fixed mealtimes and meal content.
Coverage of post-lunch glucose often suboptimal.
Difficult to reach targets for blood glucose without hypoglycemia.
Morning N: based on pre-dinner BGM.
Morning R: based on pre-lunch BGM.
Morning RAA: based on post-breakfast or pre-lunch BGM.
Evening R: based on bedtime BGM.
Evening RAA: based on post-dinner or bedtime BGM.
Evening N: based on fasting BGM.
Regimens that more closely mimic normal insulin secretion
Insulin pump therapy (hybrid closed-loop, low-glucose suspend, CGM-augmented open-loop, BGM-augmented open-loop) Basal delivery of URAA or RAA; generally 40–60% of TDD.
Mealtime and correction: URAA or RAA by bolus based on ICR and/or ISF and target glucose, with pre-meal insulin ∼15 min before eating.
Can adjust basal rates for varying insulin sensitivity by time of day, for exercise and for sick days.
Flexibility in meal timing and content.
Pump can deliver insulin in increments of fractions of units.
Potential for integration with CGM for low-glucose suspend or hybrid closed-loop.
TIR % highest and TBR % lowest with: hybrid closed-loop > low-glucose suspend > CGM-augmented open-loop > BGM-augmented open-loop.
Most expensive regimen.
Must continuously wear one or more devices.
Risk of rapid development of ketosis or DKA with interruption of insulin delivery.
Potential reactions to adhesives and site infections.
Most technically complex approach (harder for people with lower numeracy or literacy skills).
Mealtime insulin: if carbohydrate counting is accurate, change ICR if glucose after meal consistently out of target.
Correction insulin: adjust ISF and/or target glucose if correction does not consistently bring glucose into range.
Basal rates: adjust based on overnight, fasting or daytime glucose outside of activity of URAA/RAA bolus.
MDI: LAA + flexible doses of URAA or RAA at meals LAA once daily (insulin detemir or insulin glargine may require twice-daily dosing); generally 50% of TDD.
Mealtime and correction: URAA or RAA based on ICR and/or ISF and target glucose.
Can use pens for all components.
Flexibility in meal timing and content.
Insulin analogs cause less hypoglycemia than human insulins.
At least four daily injections.
Most costly insulins.
Smallest increment of insulin is 1 unit (0.5 unit with some pens).
LAAs may not cover strong dawn phenomenon (rise in glucose in early morning hours) as well as pump therapy.
Mealtime insulin: if carbohydrate counting is accurate, change ICR if glucose after meal consistently out of target.
Correction insulin: adjust ISF and/or target glucose if correction does not consistently bring glucose into range.
LAA: based on overnight or fasting glucose or daytime glucose outside of activity time course, or URAA or RAA injections.
MDI regimens with less flexibility
Four injections daily with fixed doses of N and RAA Pre-breakfast: RAA ∼20% of TDD.
Pre-lunch: RAA ∼10% of TDD.
Pre-dinner: RAA ∼10% of TDD.
Bedtime: N ∼50% of TDD.
May be feasible if unable to carbohydrate count.
All meals have RAA coverage.
N is less expensive than LAAs.
Shorter duration RAA may lead to basal deficit during day; may need twice-daily N.
Greater risk of nocturnal hypoglycemia with N.
Requires relatively consistent mealtimes and carbohydrate intake.
Pre-breakfast RAA: based on BGM after breakfast or before lunch.
Pre-lunch RAA: based on BGM after lunch or before dinner.
Pre-dinner RAA: based on BGM after dinner or at bedtime.
Evening N: based on fasting or overnight BGM.
Four injections daily with fixed doses of N and R Pre-breakfast: R ∼20% of TDD.
Pre-lunch: R ∼10% of TDD.
Pre-dinner: R ∼10% of TDD.
Bedtime: N ∼50% of TDD.
May be feasible if unable to carbohydrate count.
R can be dosed based on ICR and correction.
All meals have R coverage.
Least expensive insulins.
Greater risk of nocturnal hypoglycemia with N.
Greater risk of delayed post-meal hypoglycemia with R.
Requires relatively consistent mealtimes and carbohydrate intake.
R must be injected at least 30 min before meal for better effect.
Pre-breakfast R: based on BGM after breakfast or before lunch.
Pre-lunch R: based on BGM after lunch or before dinner.
Pre-dinner R: based on BGM after dinner or at bedtime.
Evening N: based on fasting or overnight BGM.
Regimens with fewer daily injections
Three injections daily: N+R or N+RAA Pre-breakfast: ∼40% N + ∼15% R or RAA.
Pre-dinner: ∼15% R or RAA.
Bedtime: 30% N.
Morning insulins can be mixed in one syringe.
May be appropriate for those who cannot take injection in middle of day.
Morning N covers lunch to some extent.
Same advantages of RAAs over R.
Least (N+R) or less expensive insulins than MDI with analogs.
Greater risk of nocturnal hypoglycemia with N than LAAs.
Greater risk of delayed post-meal hypoglycemia with R than RAAs.
Requires relatively consistent mealtimes and carbohydrate intake.
Coverage of post-lunch glucose often suboptimal.
R must be injected at least 30 min before meal for better effect.
Morning N: based on pre-dinner BGM.
Morning R: based on pre-lunch BGM.
Morning RAA: based on post-breakfast or pre-lunch BGM.
Pre-dinner R: based on bedtime BGM.
Pre-dinner RAA: based on post-dinner or bedtime BGM.
Evening N: based on fasting BGM.
Twice-daily “split-mixed”: N+R or N+RAA Pre-breakfast: ∼40% N + ∼15% R or RAA.
Pre-dinner: ∼30% N + ∼15% R or RAA.
Least number of injections for people with strong preference for this.
Insulins can be mixed in one syringe.
Least (N+R) or less (N+RAA) expensive insulins vs analogs.
Eliminates need for doses during the day.
Risk of hypoglycemia in afternoon or middle of night from N.
Fixed mealtimes and meal content.
Coverage of post-lunch glucose often suboptimal.
Difficult to reach targets for blood glucose without hypoglycemia.
Morning N: based on pre-dinner BGM.
Morning R: based on pre-lunch BGM.
Morning RAA: based on post-breakfast or pre-lunch BGM.
Evening R: based on bedtime BGM.
Evening RAA: based on post-dinner or bedtime BGM.
Evening N: based on fasting BGM.
BGM, blood glucose monitoring; CGM, continuous glucose monitoring; ICR, insulin-to-carbohydrate ratio; ISF, insulin sensitivity factor; LAA, long-acting analog; MDI, multiple daily injections; N, NPH insulin; R, short-acting (regular) insulin; RAA, rapid-acting analog; TDD, total daily insulin dose; URAA, ultra-rapid-acting analog. Reprinted from Holt et al. (5).
Insulin Injection Technique
Ensuring that individuals and/or caregivers understand correct insulin injection technique is important to optimize glucose control and insulin use safety. Thus, it is important that insulin be delivered into the proper tissue in the correct way. Recommendations have been published elsewhere outlining best practices for insulin injection (28). Proper insulin injection technique includes injecting into appropriate body areas, injection site rotation, appropriate care of injection sites to avoid infection or other complications, and avoidance of intramuscular (IM) insulin delivery.
Exogenously delivered insulin should be injected into subcutaneous tissue, not intramuscularly. Recommended sites for insulin injection include the abdomen, thigh, buttock, and upper arm. Insulin absorption from IM sites differs from that in subcutaneous sites and is also influenced by the activity of the muscle. Inadvertent IM injection can lead to unpredictable insulin absorption and variable effects on glucose and is associated with frequent and unexplained hypoglycemia. Risk for IM insulin delivery is increased in younger, leaner individuals when injecting into the limbs rather than truncal sites (abdomen and buttocks) and when using longer needles. Recent evidence supports the use of short needles (e.g., 4-mm pen needles) as effective and well tolerated when compared with longer needles, including a study performed in adults with obesity (29).
Injection site rotation is additionally necessary to avoid lipohypertrophy, an accumulation of subcutaneous fat in response to the adipogenic actions of insulin at a site of multiple injections. Lipohypertrophy appears as soft, smooth raised areas several centimeters in breadth and can contribute to erratic insulin absorption, increased glycemic variability, and unexplained hypoglycemic episodes. People treated with insulin and/or caregivers should receive education about proper injection site rotation and how to recognize and avoid areas of lipohypertrophy. As noted in Table 4.1, examination of insulin injection sites for the presence of lipohypertrophy, as well as assessment of injection device use and injection technique, are key components of a comprehensive diabetes medical evaluation and treatment plan. Proper insulin injection technique may lead to more effective use of this therapy and, as such, holds the potential for improved clinical outcomes.
Noninsulin Treatments for Type 1 Diabetes
Injectable and oral glucose-lowering drugs have been studied for their efficacy as adjuncts to insulin treatment of type 1 diabetes. Pramlintide is based on the naturally occurring β-cell peptide amylin and is approved for use in adults with type 1 diabetes. Clinical trials have demonstrated a modest reduction in A1C (0.3–0.4%) and modest weight loss (∼1 kg) with pramlintide (3033). Similarly, results have been reported for several agents currently approved only for the treatment of type 2 diabetes. The addition of metformin in adults with type 1 diabetes caused small reductions in body weight and lipid levels but did not improve A1C (34,35). The largest clinical trials of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) in type 1 diabetes have been conducted with liraglutide 1.8 mg daily, showing modest A1C reductions (∼0.4%), decreases in weight (∼5 kg), and reductions in insulin doses (36,37). Similarly, sodium–glucose cotransporter 2 (SGLT2) inhibitors have been studied in clinical trials in people with type 1 diabetes, showing improvements in A1C, reduced body weight, and improved blood pressure (3840); however, SGLT2 inhibitor use in type 1 diabetes is associated with an increased rate of diabetic ketoacidosis. The risks and benefits of adjunctive agents continue to be evaluated, with consensus statements providing guidance on patient selection and precautions (41).
Pancreas and Islet Transplantation
Successful pancreas and islet transplantation can normalize glucose levels and mitigate microvascular complications of type 1 diabetes. However, people receiving these treatments require lifelong immunosuppression to prevent graft rejection and/or recurrence of autoimmune islet destruction. Given the potential adverse effects of immunosuppressive therapy, pancreas transplantation should be reserved for people with type 1 diabetes undergoing simultaneous renal transplantation, following renal transplantation, or for those with recurrent ketoacidosis or severe hypoglycemia despite intensive glycemic management (42).
The 2021 ADA/EASD consensus report on the management of type 1 diabetes in adults offers a simplified overview of indications for β-cell replacement therapy in people with type 1 diabetes (Fig. 9.2 ) (5).
Figure 9.2
Simplified overview of indications for β-cell replacement therapy in people with type 1 diabetes. The two main forms of β-cell replacement therapy are whole-pancreas transplantation or islet cell transplantation. β-Cell replacement therapy can be combined with kidney transplantation if the individual has end-stage renal disease, which may be performed simultaneously or after kidney transplantation. All decisions about transplantation must balance the surgical risk, metabolic need, and the choice of the individual with diabetes. GFR, glomerular filtration rate. Reprinted from Holt et al. (5).
Figure 9.2
Simplified overview of indications for β-cell replacement therapy in people with type 1 diabetes. The two main forms of β-cell replacement therapy are whole-pancreas transplantation or islet cell transplantation. β-Cell replacement therapy can be combined with kidney transplantation if the individual has end-stage renal disease, which may be performed simultaneously or after kidney transplantation. All decisions about transplantation must balance the surgical risk, metabolic need, and the choice of the individual with diabetes. GFR, glomerular filtration rate. Reprinted from Holt et al. (5).
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Recommendations
• 9.4a Healthy lifestyle behaviors, diabetes self-management education and support, avoidance of clinical inertia, and social determinants of health should be considered in the glucose-lowering management of type 2 diabetes. Pharmacologic therapy should be guided by person-centered treatment factors, including comorbidities and treatment goals. A
• 9.4b In adults with type 2 diabetes and established/high risk of atherosclerotic cardiovascular disease, heart failure, and/or chronic kidney disease, the treatment regimen should include agents that reduce cardiorenal risk (Fig. 9.3 and Table 9.2 ). A
• 9.4c Pharmacologic approaches that provide adequate efficacy to achieve and maintain treatment goals should be considered, such as metformin or other agents, including combination therapy (Fig. 9.3 and Table 9.2 ). A
• 9.4d Weight management is an impactful component of glucose-lowering management in type 2 diabetes. The glucose-lowering treatment regimen should consider approaches that support weight management goals (Fig. 9.3 and Table 9.2 ). A
• 9.5 Metformin should be continued upon initiation of insulin therapy (unless contraindicated or not tolerated) for ongoing glycemic and metabolic benefits. A
• 9.6 Early combination therapy can be considered in some individuals at treatment initiation to extend the time to treatment failure. A
• 9.7 The early introduction of insulin should be considered if there is evidence of ongoing catabolism (weight loss), if symptoms of hyperglycemia are present, or when A1C levels (>10% [86 mmol/mol]) or blood glucose levels (≥300 mg/dL [16.7 mmol/L]) are very high. E
• 9.8 A person-centered approach should guide the choice of pharmacologic agents. Consider the effects on cardiovascular and renal comorbidities, efficacy, hypoglycemia risk, impact on weight, cost and access, risk for side effects, and individual preferences (Fig. 9.3 and Table 9.2 ). E
• 9.9 Among individuals with type 2 diabetes who have established atherosclerotic cardiovascular disease or indicators of high cardiovascular risk, established kidney disease, or heart failure, a sodium–glucose cotransporter 2 inhibitor and/or glucagon-like peptide 1 receptor agonist with demonstrated cardiovascular disease benefit (Fig. 9.3 , Table 9.2 , Table 10.3B, and Table 10.3C) is recommended as part of the glucose-lowering regimen and comprehensive cardiovascular risk reduction, independent of A1C and in consideration of person-specific factors (Fig. 9.3 ) (see Section 10, “Cardiovascular Disease and Risk Management,” for details on cardiovascular risk reduction recommendations). A
• 9.10 In adults with type 2 diabetes, a glucagon-like peptide 1 receptor agonist is preferred to insulin when possible. A
• 9.11 If insulin is used, combination therapy with a glucagon-like peptide 1 receptor agonist is recommended for greater efficacy, durability of treatment effect, and weight and hypoglycemia benefit. A
• 9.12 Recommendation for treatment intensification for individuals not meeting treatment goals should not be delayed. A
• 9.13 Medication regimen and medication-taking behavior should be reevaluated at regular intervals (every 3–6 months) and adjusted as needed to incorporate specific factors that impact choice of treatment (Fig. 4.1 and Table 9.2 ). E
• 9.14 Clinicians should be aware of the potential for overbasalization with insulin therapy. Clinical signals that may prompt evaluation of overbasalization include basal dose more than ∼0.5 units/kg/day, high bedtime–morning or postpreprandial glucose differential, hypoglycemia (aware or unaware), and high glycemic variability. Indication of overbasalization should prompt reevaluation to further individualize therapy. E
The ADA/EASD consensus report “Management of Hyperglycemia in Type 2 Diabetes, 2022” (4345) recommends a holistic, multifactorial person-centered approach accounting for the lifelong nature of type 2 diabetes. Person-specific factors that affect choice of treatment include individualized glycemic and weight goals, impact on weight, hypoglycemia and cardiorenal protection (see Section 10, “Cardiovascular Disease and Risk Management,” and Section 11 “Chronic Kidney Disease and Risk Management”), underlying physiologic factors, side effect profiles of medications, complexity of regimen, regimen choice to optimize medication use and reduce treatment discontinuation, and access, cost, and availability of medication. Lifestyle modifications and health behaviors that improve health (see Section 5, “Facilitating Positive Health Behaviors and Well-being to Improve Health Outcomes”) should be emphasized along with any pharmacologic therapy. Section 13, “Older Adults,” and Section 14, “Children and Adolescents,” have recommendations specific for older adults and for children and adolescents with type 2 diabetes, respectively. Section 10, “Cardiovascular Disease and Risk Management,” and Section 11, “Chronic Kidney Disease and Risk Management,” have recommendations for the use of glucose-lowering drugs in the management of cardiovascular and renal disease, respectively.
Choice of Glucose-Lowering Therapy
Healthy lifestyle behaviors, diabetes self-management, education, and support, avoidance of clinical inertia, and social determinants of health should be considered in the glucose-lowering management of type 2 diabetes. Pharmacologic therapy should be guided by person-centered treatment factors, including comorbidities and treatment goals. Pharmacotherapy should be started at the time type 2 diabetes is diagnosed unless there are contraindications. Pharmacologic approaches that provide the efficacy to achieve treatment goals should be considered, such as metformin or other agents, including combination therapy, that provide adequate efficacy to achieve and maintain treatment goals (45). In adults with type 2 diabetes and established/high risk of atherosclerotic cardiovascular disease (ASCVD), heart failure (HF), and/or chronic kidney disease (CKD), the treatment regimen should include agents that reduce cardiorenal risk (see Fig. 9.3 , Table 9.2 , Section 10, “Cardiovascular Disease and Risk Management,” and Section 11, “Chronic Kidney Disease and Risk Management”). Pharmacologic approaches that provide the efficacy to achieve treatment goals should be considered, specified as metformin or agent(s), including combination therapy, that provide adequate efficacy to achieve and maintain treatment goals ( Fig. 9.3 and Table 9.2 ). In general, higher-efficacy approaches have greater likelihood of achieving glycemic goals, with the following considered to have very high efficacy for glucose lowering: the GLP-1 RAs dulaglutide (high dose) and semaglutide, the gastric inhibitory peptide (GIP) and GLP-1 RA tirzepatide, insulin, combination oral therapy, and combination injectable therapy. Weight management is an impactful component of glucose-lowering management in type 2 diabetes (45,46). The glucose-lowering treatment regimen should consider approaches that support weight management goals, with very high efficacy for weight loss seen with semaglutide and tirzepatide (Fig. 9.3 and Table 9.2 ) (45).
Figure 9.3
Use of glucose-lowering medications in the management of type 2 diabetes. ACEi, angiotensin-converting enzyme inhibitor; ACR, albumin-to-creatinine ratio; ARB, angiotensin receptor blocker; ASCVD, atherosclerotic cardiovascular disease; CGM, continuous glucose monitoring; CKD, chronic kidney disease; CV, cardiovascular; CVD, cardiovascular disease; CVOT, cardiovascular outcomes trial; DPP-4i, dipeptidyl peptidase 4 inhibitor; eGFR, estimated glomerular filtration rate; GLP-1 RA, glucagon-like peptide 1 receptor agonist; HF, heart failure; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; HHF, hospitalization for heart failure; MACE, major adverse cardiovascular events; MI, myocardial infarction; SDOH, social determinants of health; SGLT2i, sodium-glucose cotransporter 2 inhibitor; T2D, type 2 diabetes; TZD, thiazolidinedione. Adapted from Davies et al. (45).
Figure 9.3
Use of glucose-lowering medications in the management of type 2 diabetes. ACEi, angiotensin-converting enzyme inhibitor; ACR, albumin-to-creatinine ratio; ARB, angiotensin receptor blocker; ASCVD, atherosclerotic cardiovascular disease; CGM, continuous glucose monitoring; CKD, chronic kidney disease; CV, cardiovascular; CVD, cardiovascular disease; CVOT, cardiovascular outcomes trial; DPP-4i, dipeptidyl peptidase 4 inhibitor; eGFR, estimated glomerular filtration rate; GLP-1 RA, glucagon-like peptide 1 receptor agonist; HF, heart failure; HFpEF, heart failure with preserved ejection fraction; HFrEF, heart failure with reduced ejection fraction; HHF, hospitalization for heart failure; MACE, major adverse cardiovascular events; MI, myocardial infarction; SDOH, social determinants of health; SGLT2i, sodium-glucose cotransporter 2 inhibitor; T2D, type 2 diabetes; TZD, thiazolidinedione. Adapted from Davies et al. (45).
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Table 9.2
Medications for lowering glucose, summary of characteristics
CV, cardiovascular; CVOT, cardiovascular outcomes trial; DKA, diabetic ketoacidosis; DKD, diabetic kidney disease; DPP-4, dipeptidyl peptidase 4; eGFR, estimated glomerular filtration rate; FDA, U.S. Food and Drug Administration; GI, gastrointestinal; GIP, gastric inhibitory polypeptide; GLP-1 RA, glucagon-like peptide 1 receptor agonist; HF, heart failure; NASH, nonalcoholic steatohepatitis; MACE, major adverse cardiovascular events; SGLT2, sodium–glucose cotransporter 2; SQ, subcutaneous; T2DM, type 2 diabetes mellitus.
*
For agent-specific dosing recommendations, please refer to manufacturers’ prescribing information.
1
Tsapas et al. (62).
2
Metformin is effective and safe, is inexpensive, and may reduce risk of cardiovascular events and death (47). Metformin is available in an immediate-release form for twice-daily dosing or as an extended-release form that can be given once daily. Compared with sulfonylureas, metformin as first-line therapy has beneficial effects on A1C, weight, and cardiovascular mortality (48).
The principal side effects of metformin are gastrointestinal intolerance due to bloating, abdominal discomfort, and diarrhea; these can be mitigated by gradual dose titration. The drug is cleared by renal filtration, and very high circulating levels (e.g., as a result of overdose or acute renal failure) have been associated with lactic acidosis. However, the occurrence of this complication is now known to be very rare, and metformin may be safely used in people with reduced estimated glomerular filtration rates (eGFR); the FDA has revised the label for metformin to reflect its safety in people with eGFR ≥30 mL/min/1.73 m2 (49). A randomized trial confirmed previous observations that metformin use is associated with vitamin B12 deficiency and worsening of symptoms of neuropathy (50). This is compatible with a report from the Diabetes Prevention Program Outcomes Study (DPPOS) suggesting periodic testing of vitamin B12 (51) (see Section 3, “Prevention or Delay of Type 2 Diabetes and Associated Comorbidities”).
When A1C is ≥1.5% (12.5 mmol/mol) above the glycemic target (see Section 6, “Glycemic Targets,” for appropriate targets), many individuals will require dual-combination therapy or a more potent glucose-lowering agent to achieve and maintain their target A1C level (45,52) (Fig. 9.3 and Table 9.2 ). Insulin has the advantage of being effective where other agents are not and should be considered as part of any combination regimen when hyperglycemia is severe, especially if catabolic features (weight loss, hypertriglyceridemia, ketosis) are present. It is common practice to initiate insulin therapy for people who present with blood glucose levels ≥300 mg/dL (16.7 mmol/L) or A1C >10% (86 mmol/mol) or if the individual has symptoms of hyperglycemia (i.e., polyuria or polydipsia) or evidence of catabolism (weight loss) (Fig. 9.4 ). As glucose toxicity resolves, simplifying the regimen and/or changing to noninsulin agents is often possible. However, there is evidence that people with uncontrolled hyperglycemia associated with type 2 diabetes can also be effectively treated with a sulfonylurea (53).
Figure 9.4
Intensifying to injectable therapies in type 2 diabetes. DSMES, diabetes self-management education and support; FPG, fasting plasma glucose; GLP-1 RA, glucagon-like peptide 1 receptor agonist; max, maximum; PPG, postprandial glucose. Adapted from Davies et al. (43).
Figure 9.4
Intensifying to injectable therapies in type 2 diabetes. DSMES, diabetes self-management education and support; FPG, fasting plasma glucose; GLP-1 RA, glucagon-like peptide 1 receptor agonist; max, maximum; PPG, postprandial glucose. Adapted from Davies et al. (43).
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Combination Therapy
Because type 2 diabetes is a progressive disease in many individuals, maintenance of glycemic targets often requires combination therapy. Traditional recommendations have been to use stepwise addition of medications to metformin to maintain A1C at target. The advantage of this is to provide a clear assessment of the positive and negative effects of new drugs and reduce potential side effects and expense (54). However, there are data to support initial combination therapy for more rapid attainment of glycemic goals (55,56) and later combination therapy for longer durability of glycemic effect (57). The VERIFY (Vildagliptin Efficacy in combination with metfoRmln For earlY treatment of type 2 diabetes) trial demonstrated that initial combination therapy is superior to sequential addition of medications for extending primary and secondary failure (58). In the VERIFY trial, participants receiving the initial combination of metformin and the dipeptidyl peptidase 4 (DPP-4) inhibitor vildagliptin had a slower decline of glycemic control compared with metformin alone and with vildagliptin added sequentially to metformin. These results have not been generalized to oral agents other than vildagliptin, but they suggest that more intensive early treatment has some benefits and should be considered through a shared decision-making process, as appropriate. Initial combination therapy should be considered in people presenting with A1C levels 1.5–2.0% above target. Finally, incorporation of high-glycemic-efficacy therapies or therapies for cardiovascular/renal risk reduction (e.g., GLP-1 RAs, SGLT2 inhibitors) may allow for weaning of the current regimen, particularly of agents that may increase the risk of hypoglycemia. Thus, treatment intensification may not necessarily follow a pure sequential addition of therapy but instead reflect a tailoring of the regimen in alignment with person-centered treatment goals (Fig. 9.3 ).
Recommendations for treatment intensification for people not meeting treatment goals should not be delayed. Shared decision-making is important in discussions regarding treatment intensification. The choice of medication added to initial therapy is based on the clinical characteristics of the individual and their preferences. Important clinical characteristics include the presence of established ASCVD or indicators of high ASCVD risk, HF, CKD, obesity, nonalcoholic fatty liver disease or nonalcoholic steatohepatitis, and risk for specific adverse drug effects, as well as safety, tolerability, and cost. Results from comparative effectiveness meta-analyses suggest that each new class of noninsulin agents added to initial therapy with metformin generally lowers A1C approximately 0.7–1.0% (59,60) (Fig. 9.3 and Table 9.2 ).
For people with type 2 diabetes and established ASCVD or indicators of high ASCVD risk, HF, or CKD, an SGLT2 inhibitor and/or GLP-1 RA with demonstrated CVD benefit (see Table 9.2 , Table 10.3B, Table 10.3C, and Section 10, “Cardiovascular Disease and Risk Management”) is recommended as part of the glucose-lowering regimen independent of A1C, independent of metformin use and in consideration of person-specific factors (Fig. 9.3 ). For people without established ASCVD, indicators of high ASCVD risk, HF, or CKD, medication choice is guided by efficacy in support of individualized glycemic and weight management goals, avoidance of side effects (particularly hypoglycemia and weight gain), cost/access, and individual preferences (61). A systematic review and network meta-analysis suggests greatest reductions in A1C level with insulin regimens and specific GLP-1 RAs added to metformin-based background therapy (62). In all cases, treatment regimens need to be continuously reviewed for efficacy, side effects, and burden (Table 9.2 ). In some instances, the individual will require medication reduction or discontinuation. Common reasons for this include ineffectiveness, intolerable side effects, expense, or a change in glycemic goals (e.g., in response to development of comorbidities or changes in treatment goals). Section 13, “Older Adults,” has a full discussion of treatment considerations in older adults, in whom changes of glycemic goals and de-escalation of therapy are common.
The need for the greater potency of injectable medications is common, particularly in people with a longer duration of diabetes. The addition of basal insulin, either human NPH or one of the long-acting insulin analogs, to oral agent regimens is a well-established approach that is effective for many individuals. In addition, evidence supports the utility of GLP-1 RAs in people not at glycemic goal. While most GLP-1 RAs are injectable, an oral formulation of semaglutide is commercially available (63). In trials comparing the addition of an injectable GLP-1 RA or insulin in people needing further glucose lowering, glycemic efficacy of injectable GLP-1 RA was similar or greater than that of basal insulin (6470). GLP-1 RAs in these trials had a lower risk of hypoglycemia and beneficial effects on body weight compared with insulin, albeit with greater gastrointestinal side effects. Thus, trial results support GLP-1 RAs as the preferred option for individuals requiring the potency of an injectable therapy for glucose control (Fig. 9.4 ). In individuals who are intensified to insulin therapy, combination therapy with a GLP-1 RA has been shown to have greater efficacy and durability of glycemic treatment effect, as well as weight and hypoglycemia benefit, than treatment intensification with insulin alone (45). However, cost and tolerability issues are important considerations in GLP-1 RA use.
Costs for diabetes medications have increased dramatically over the past two decades, and an increasing proportion is now passed on to patients and their families (71). Table 9.3 provides cost information for currently approved noninsulin therapies. Of note, prices listed are average wholesale prices (AWP) (72) and National Average Drug Acquisition Costs (NADAC) (73), separate measures to allow for a comparison of drug prices, but do not account for discounts, rebates, or other price adjustments often involved in prescription sales that affect the actual cost incurred by the patient. Medication costs can be a major source of stress for people with diabetes and contribute to worse medication-taking behavior (74); cost-reducing strategies may improve medication-taking behavior in some cases (75).
Table 9.3
Median monthly (30-day) AWP and NADAC of maximum approved daily dose of noninsulin glucose-lowering agents in the U.S.
ClassCompound(s)Dosage strength/product (if applicable)Median AWP (min, max)Median NADAC (min, max)Maximum approved daily dose*
Biguanides • Metformin 850 mg (IR) $106 ($5, $189)$2 2,550 mg
1,000 mg (IR) $87 ($3, $144)$2 2,000 mg
1,000 mg (ER) $242 ($242, $7,214)$32 ($32,$160) 2,000 mg
Sulfonylureas (2nd generation) • Glimepiride 4 mg $74 ($71, $198)$3 8 mg
• Glipizide 10 mg (IR) $70 ($67, $91)$6 40 mg
10 mg (XL/ER) $48 ($46, $48)$11 20 mg
• Glyburide 6 mg (micronized) $52 ($48, $71)$12 12 mg
5 mg $79 ($63, $93)$9 20 mg
Thiazolidinedione • Pioglitazone 45 mg $345 ($7, $349)$4 45 mg
α-Glucosidase inhibitors • Acarbose 100 mg $106 ($104, $106)$29 300 mg
• Miglitol 100 mg $241 ($241, $346) NA 300 mg Meglitinides • Nateglinide 120 mg$155 $27 360 mg • Repaglinide 2 mg$878 ($58,$897) $31 16 mg DPP-4 inhibitors • Alogliptin 25 mg$234 $154 25 mg • Saxagliptin 5 mg$565 $452 5 mg • Linagliptin 5 mg$606 $485 5 mg • Sitagliptin 100 mg$626 $500 100 mg SGLT2 inhibitors • Ertugliflozin 15 mg$390 $312 15 mg • Dapagliflozin 10 mg$659 $527 10 mg • Canagliflozin 300 mg$684 $548 300 mg • Empagliflozin 25 mg$685 $547 25 mg GLP-1 RAs • Exenatide (extended release) 2 mg powder for suspension or pen$936 $726 2 mg** • Exenatide 10 μg pen$961 $770 20 μg • Dulaglutide 4.5 mg mL pen$1,064 $852 4.5 mg** • Semaglutide 1 mg pen$1,070 $858 2 mg** 14 mg (tablet)$1,070 $858 14 mg • Liraglutide 1.8 mg pen$1,278 $1,022 1.8 mg • Lixisenatide 20 μg pen$814 NA 20 μg
GLP-1/GIP dual agonist • Tirzepatide 15 mg pen $1,169$935 15 mg**
Bile acid sequestrant • Colesevelam 625 mg tabs $711 ($674, $712)$83 3.75 g
3.75 g suspension $674 ($673, $675)$177 3.75 g
Dopamine-2 agonist • Bromocriptine 0.8 mg $1,118$899 4.8 mg
Amylin mimetic • Pramlintide 120 μg pen $2,783 NA 120 μg/injection†† ClassCompound(s)Dosage strength/product (if applicable)Median AWP (min, max)Median NADAC (min, max)Maximum approved daily dose* Biguanides • Metformin 850 mg (IR)$106 ($5,$189) $2 2,550 mg 1,000 mg (IR)$87 ($3,$144) $2 2,000 mg 1,000 mg (ER)$242 ($242,$7,214) $32 ($32, $160) 2,000 mg Sulfonylureas (2nd generation) • Glimepiride 4 mg$74 ($71,$198) $3 8 mg • Glipizide 10 mg (IR)$70 ($67,$91) $6 40 mg 10 mg (XL/ER)$48 ($46,$48) $11 20 mg • Glyburide 6 mg (micronized)$52 ($48,$71) $12 12 mg 5 mg$79 ($63,$93) $9 20 mg Thiazolidinedione • Pioglitazone 45 mg$345 ($7,$349) $4 45 mg α-Glucosidase inhibitors • Acarbose 100 mg$106 ($104,$106) $29 300 mg • Miglitol 100 mg$241 ($241,$346) NA 300 mg
Meglitinides • Nateglinide 120 mg $155$27 360 mg
• Repaglinide 2 mg $878 ($58, $897)$31 16 mg
DPP-4 inhibitors • Alogliptin 25 mg $234$154 25 mg
• Saxagliptin 5 mg $565$452 5 mg
• Linagliptin 5 mg $606$485 5 mg
• Sitagliptin 100 mg $626$500 100 mg
SGLT2 inhibitors • Ertugliflozin 15 mg $390$312 15 mg
• Dapagliflozin 10 mg $659$527 10 mg
• Canagliflozin 300 mg $684$548 300 mg
• Empagliflozin 25 mg $685$547 25 mg
GLP-1 RAs • Exenatide (extended release) 2 mg powder for suspension or pen $936$726 2 mg**
• Exenatide 10 μg pen $961$770 20 μg
• Dulaglutide 4.5 mg mL pen $1,064$852 4.5 mg**
• Semaglutide 1 mg pen $1,070$858 2 mg**
14 mg (tablet) $1,070$858 14 mg
• Liraglutide 1.8 mg pen $1,278$1,022 1.8 mg
• Lixisenatide 20 μg pen $814 NA 20 μg GLP-1/GIP dual agonist • Tirzepatide 15 mg pen$1,169 $935 15 mg** Bile acid sequestrant • Colesevelam 625 mg tabs$711 ($674,$712) $83 3.75 g 3.75 g suspension$674 ($673,$675) $177 3.75 g Dopamine-2 agonist • Bromocriptine 0.8 mg$1,118 $899 4.8 mg Amylin mimetic • Pramlintide 120 μg pen$2,783 NA 120 μg/injection††
AWP, average wholesale price; DPP-4, dipeptidyl peptidase 4; ER and XL, extended release; GIP, glucose-dependent insulinotropic polypeptide; GLP-1 RA, glucagon-like peptide 1 receptor agonist; IR, immediate release; max, maximum; min, minimum; NA, data not available; NADAC, National Average Drug Acquisition Cost; SGLT2, sodium-glucose cotransporter 2.
Calculated for 30-day supply (AWP [72] or NADAC [73] unit price × number of doses required to provide maximum approved daily dose × 30 days); median AWP or NADAC listed alone when only one product and/or price.
*
Utilized to calculate median AWP and NADAC (min, max); generic prices used, if available commercially.
**
††
AWP and NADAC calculated based on 120 μg three times daily.
Cardiovascular Outcomes Trials
There are now multiple large randomized controlled trials reporting statistically significant reductions in cardiovascular events in adults with type 2 diabetes treated with an SGLT2 inhibitor or GLP-1 RA; see Section 10, “Cardiovascular Disease and Risk Management” for details. Participants enrolled in many of the cardiovascular outcomes trials had A1C ≥6.5%, with more than 70% taking metformin at baseline, with analyses indicating benefit with or without metformin (45). Thus, a practical extension of these results to clinical practice is to use these medications preferentially in people with type 2 diabetes and established ASCVD or indicators of high ASCVD risk. For these individuals, incorporating one of the SGLT2 inhibitors and/or GLP-1 RAs that have been demonstrated to have cardiovascular disease benefit is recommended (see Fig. 9.3 , Table 9.2 , and Section 10, “Cardiovascular Disease and Risk Management”). Emerging data suggest that use of both classes of drugs will provide additional cardiovascular and kidney outcomes benefit; thus, combination therapy with an SGLT2 inhibitor and a GLP-1 RA may be considered to provide the complementary outcomes benefits associated with these classes of medication (76). In cardiovascular outcomes trials, empagliflozin, canagliflozin, dapagliflozin, liraglutide, semaglutide, and dulaglutide all had beneficial effects on indices of CKD, while dedicated renal outcomes studies have demonstrated benefit of specific SGLT2 inhibitors. See Section 11, “Chronic Kidney Disease and Risk Management,” for discussion of how CKD may impact treatment choices. Additional large randomized trials of other agents in these classes are ongoing.
Insulin Therapy
Many adults with type 2 diabetes eventually require and benefit from insulin therapy (Fig. 9.4 ). See the section insulin injection technique, above, for guidance on how to administer insulin safely and effectively. The progressive nature of type 2 diabetes should be regularly and objectively explained to patients, and clinicians should avoid using insulin as a threat or describing it as a sign of personal failure or punishment. Rather, the utility and importance of insulin to maintain glycemic control once progression of the disease overcomes the effect of other agents should be emphasized. Educating and involving patients in insulin management is beneficial. For example, instruction of individuals with type 2 diabetes initiating insulin in self-titration of insulin doses based on glucose monitoring improves glycemic control (77). Comprehensive education regarding blood glucose monitoring, nutrition, and the avoidance and appropriate treatment of hypoglycemia are critically important in any individual using insulin.
Basal Insulin
Basal insulin alone is the most convenient initial insulin treatment and can be added to metformin and other noninsulin injectables. Starting doses can be estimated based on body weight (0.1–0.2 units/kg/day) and the degree of hyperglycemia, with individualized titration over days to weeks as needed. The principal action of basal insulin is to restrain hepatic glucose production and limit hyperglycemia overnight and between meals (78,79). Control of fasting glucose can be achieved with human NPH insulin or a long-acting insulin analog. In clinical trials, long-acting basal analogs (U-100 glargine or detemir) have been demonstrated to reduce the risk of symptomatic and nocturnal hypoglycemia compared with NPH insulin (8085), although these advantages are modest and may not persist (86). Longer-acting basal analogs (U-300 glargine or degludec) may convey a lower hypoglycemia risk compared with U-100 glargine when used in combination with oral agents (8793). Clinicians should be aware of the potential for overbasalization with insulin therapy. Clinical signals that may prompt evaluation of overbasalization include basal dose greater than ∼0.5 units/kg, high bedtime–morning or postpreprandial glucose differential (e.g., bedtime–morning glucose differential ≥50 mg/dL), hypoglycemia (aware or unaware), and high variability. Indication of overbasalization should prompt reevaluation to further individualize therapy (94).
The cost of insulin has been rising steadily over the past two decades, at a pace severalfold that of other medical expenditures (95). This expense contributes significant burden to patients as insulin has become a growing “out-of-pocket” cost for people with diabetes, and direct patient costs contribute to decrease in medication-taking behavior (95). Therefore, consideration of cost is an important component of effective management. For many individuals with type 2 diabetes (e.g., individuals with relaxed A1C goals, low rates of hypoglycemia, and prominent insulin resistance, as well as those with cost concerns), human insulin (NPH and regular) may be the appropriate choice of therapy, and clinicians should be familiar with its use (96). Human regular insulin, NPH, and 70/30 NPH/regular products can be purchased for considerably less than the AWP and NADAC prices listed in Table 9.4 at select pharmacies. Additionally, approval of follow-on biologics for insulin glargine, the first interchangeable insulin glargine product, and generic versions of analog insulins may expand cost-effective options.
Table 9.4
Median cost of insulin products in the U.S. calculated as AWP (72) and NADAC (73) per 1,000 units of specified dosage form/product
InsulinsCompoundsDosage form/productMedian AWP (min, max)*Median NADAC*
Rapid-acting • Lispro follow-on product U-100 vial $118 ($118, $157)$94
U-100 prefilled pen $151$121
• Lispro U-100 vial $99$79
U-100 cartridge $408$326
U-100 prefilled pen $127$102
U-200 prefilled pen $424$339
• Lispro-aabc U-100 vial $330$261
U-100 prefilled pen $424$339
U-200 prefilled pen $424 NA • Glulisine U-100 vial$341 $272 U-100 prefilled pen$439 $351 • Aspart U-100 vial$174 $140 U-100 cartridge$215 $172 U-100 prefilled pen$224 $180 • Aspart (“faster acting product”) U-100 vial$347 $277 U-100 cartridge$430 $344 U-100 prefilled pen$447 $357 • Inhaled insulin Inhalation cartridges$1,418 NA
Short-acting • Human regular U-100 vial $165††$132††
U-100 prefilled pen $208$166
Intermediate-acting • Human NPH U-100 vial $165††$132††
U-100 prefilled pen $208$168
Concentrated human regular insulin • U-500 human regular insulin U-500 vial $178$142
U-500 prefilled pen $230$184
Long-acting • Glargine follow-on products U-100 prefilled pen $261 ($118, $323)$209 ($209,$258)
U-100 vial $118 ($118, $323)$95
• Glargine U-100 vial; U-100 prefilled pen $136$109
U-300 prefilled pen $346$277
• Detemir U-100 vial; U-100 prefilled pen $370$296
• Degludec U-100 vial; U-100 prefilled pen; U-200 prefilled pen $407$326
Premixed insulin products • NPH/regular 70/30 U-100 vial $165††$133††
U-100 prefilled pen $208$167
• Lispro 50/50 U-100 vial $342$274
U-100 prefilled pen $424$339
• Lispro 75/25 U-100 vial $342$273
U-100 prefilled pen $127$103
• Aspart 70/30 U-100 vial $180$146
U-100 prefilled pen $224$178
Premixed insulin/GLP-1 RA products • Glargine/Lixisenatide 100/33 μg prefilled pen $646$517
• Degludec/Liraglutide 100/3.6 μg prefilled pen $944$760
InsulinsCompoundsDosage form/productMedian AWP (min, max)*Median NADAC*
Rapid-acting • Lispro follow-on product U-100 vial $118 ($118, $157)$94
U-100 prefilled pen $151$121
• Lispro U-100 vial $99$79
U-100 cartridge $408$326
U-100 prefilled pen $127$102
U-200 prefilled pen $424$339
• Lispro-aabc U-100 vial $330$261
U-100 prefilled pen $424$339
U-200 prefilled pen $424 NA • Glulisine U-100 vial$341 $272 U-100 prefilled pen$439 $351 • Aspart U-100 vial$174 $140 U-100 cartridge$215 $172 U-100 prefilled pen$224 $180 • Aspart (“faster acting product”) U-100 vial$347 $277 U-100 cartridge$430 $344 U-100 prefilled pen$447 $357 • Inhaled insulin Inhalation cartridges$1,418 NA
Short-acting • Human regular U-100 vial $165††$132††
U-100 prefilled pen $208$166
Intermediate-acting • Human NPH U-100 vial $165††$132††
U-100 prefilled pen $208$168
Concentrated human regular insulin • U-500 human regular insulin U-500 vial $178$142
U-500 prefilled pen $230$184
Long-acting • Glargine follow-on products U-100 prefilled pen $261 ($118, $323)$209 ($209,$258)
U-100 vial $118 ($118, $323)$95
• Glargine U-100 vial; U-100 prefilled pen $136$109
U-300 prefilled pen $346$277
• Detemir U-100 vial; U-100 prefilled pen $370$296
• Degludec U-100 vial; U-100 prefilled pen; U-200 prefilled pen $407$326
Premixed insulin products • NPH/regular 70/30 U-100 vial $165††$133††
U-100 prefilled pen $208$167
• Lispro 50/50 U-100 vial $342$274
U-100 prefilled pen $424$339
• Lispro 75/25 U-100 vial $342$273
U-100 prefilled pen $127$103
• Aspart 70/30 U-100 vial $180$146
U-100 prefilled pen $224$178
Premixed insulin/GLP-1 RA products • Glargine/Lixisenatide 100/33 μg prefilled pen $646$517
• Degludec/Liraglutide 100/3.6 μg prefilled pen $944$760
AWP, average wholesale price; GLP-1 RA, glucagon-like peptide 1 receptor agonist; NA, data not available; NADAC, National Average Drug Acquisition Cost.
*
AWP or NADAC calculated as in Table 9.3 .
Generic prices used when available.
††
AWP and NADAC data presented do not include vials of regular human insulin and NPH available at Walmart for approximately \$25/vial; median listed alone when only one product and/or price.
Prandial Insulin
Many individuals with type 2 diabetes require doses of insulin before meals, in addition to basal insulin, to reach glycemic targets. If the individual is not already being treated with a GLP-1 RA, a GLP-1 RA (either in free combination or fixed-ratio combination) should be considered prior to prandial insulin to further address prandial control and to minimize the risks of hypoglycemia and weight gain associated with insulin therapy (45). For individuals who advance to prandial insulin, a prandial insulin dose of 4 units or 10% of the amount of basal insulin at the largest meal or the meal with the greatest postprandial excursion is a safe estimate for initiating therapy. The prandial insulin regimen can then be intensified based on individual needs (Fig. 9.4 ). Individuals with type 2 diabetes are generally more insulin resistant than those with type 1 diabetes, require higher daily doses (∼1 unit/kg), and have lower rates of hypoglycemia (97). Titration can be based on home glucose monitoring or A1C. With significant additions to the prandial insulin dose, particularly with the evening meal, consideration should be given to decreasing basal insulin. Meta-analyses of trials comparing rapid-acting insulin analogs with human regular insulin in type 2 diabetes have not reported important differences in A1C or hypoglycemia (98,99).
Concentrated Insulins
Several concentrated insulin preparations are currently available. U-500 regular insulin is, by definition, five times more concentrated than U-100 regular insulin. U-500 regular insulin has distinct pharmacokinetics with delayed onset and longer duration of action, has characteristics more like an intermediate-acting (NPH) insulin, and can be used as two or three daily injections (100). U-300 glargine and U-200 degludec are three and two times as concentrated as their U-100 formulations, respectively, and allow higher doses of basal insulin administration per volume used. U-300 glargine has a longer duration of action than U-100 glargine but modestly lower efficacy per unit administered (101,102). The FDA has also approved a concentrated formulation of rapid-acting insulin lispro, U-200 (200 units/mL), and insulin lispro-aabc (U-200). These concentrated preparations may be more convenient and comfortable for individuals to inject and may improve treatment plan engagement in those with insulin resistance who require large doses of insulin. While U-500 regular insulin is available in both prefilled pens and vials, other concentrated insulins are available only in prefilled pens to minimize the risk of dosing errors.
Alternative Insulin Routes
Insulins with different routes of administration (inhaled, bolus-only insulin delivery patch pump) are also available (45). Inhaled insulin is available as a rapid-acting insulin; studies in individuals with type 1 diabetes suggest rapid pharmacokinetics (8). Studies comparing inhaled insulin with injectable insulin have demonstrated its faster onset and shorter duration compared with rapid-acting insulin lispro as well as clinically meaningful A1C reductions and weight reductions compared with insulin aspart over 24 weeks (103105). Use of inhaled insulin may result in a decline in lung function (reduced forced expiratory volume in 1 s [FEV1]). Inhaled insulin is contraindicated in individuals with chronic lung disease, such as asthma and chronic obstructive pulmonary disease, and is not recommended in individuals who smoke or who recently stopped smoking. All individuals require spirometry (FEV1) testing to identify potential lung disease prior to and after starting inhaled insulin therapy.
Combination Injectable Therapy
If basal insulin has been titrated to an acceptable fasting blood glucose level (or if the dose is >0.5 units/kg/day with indications of need for other therapy) and A1C remains above target, consider advancing to combination injectable therapy (Fig. 9.4 ). This approach can use a GLP-1 RA or dual GIP and GLP-1 RA added to basal insulin or multiple doses of insulin. The combination of basal insulin and GLP-1 RA has potent glucose-lowering actions and less weight gain and hypoglycemia compared with intensified insulin regimens (106111). The DUAL VIII (Durability of Insulin Degludec Plus Liraglutide Versus Insulin Glargine U100 as Initial Injectable Therapy in Type 2 Diabetes) randomized controlled trial demonstrated greater durability of glycemic treatment effect with the combination GLP-1 RA–insulin therapy compared with addition of basal insulin alone (57). In select individuals, complex insulin regimens can also be simplified with combination GLP-1 RA–insulin therapy in type 2 diabetes (112). Two different once-daily, fixed dual combination products containing basal insulin plus a GLP-1 RA are available: insulin glargine plus lixisenatide (iGlarLixi) and insulin degludec plus liraglutide (IDegLira).
Intensification of insulin treatment can be done by adding doses of prandial insulin to basal insulin. Starting with a single prandial dose with the largest meal of the day is simple and effective, and it can be advanced to a regimen with multiple prandial doses if necessary (113). Alternatively, in an individual on basal insulin in whom additional prandial coverage is desired, the regimen can be converted to two doses of a premixed insulin. Each approach has advantages and disadvantages. For example, basal-prandial regimens offer greater flexibility for individuals who eat on irregular schedules. On the other hand, two doses of premixed insulin is a simple, convenient means of spreading insulin across the day. Moreover, human insulins, separately, self-mixed, or as premixed NPH/regular (70/30) formulations, are less costly alternatives to insulin analogs. Figure 9.4 outlines these options as well as recommendations for further intensification, if needed, to achieve glycemic goals. When initiating combination injectable therapy, metformin therapy should be maintained, while sulfonylureas and DPP-4 inhibitors are typically weaned or discontinued. In individuals with suboptimal blood glucose control, especially those requiring large insulin doses, adjunctive use of a thiazolidinedione or an SGLT2 inhibitor may help to improve control and reduce the amount of insulin needed, though potential side effects should be considered. Once a basal-bolus insulin regimen is initiated, dose titration is important, with adjustments made in both mealtime and basal insulins based on the blood glucose levels and an understanding of the pharmacodynamic profile of each formulation (also known as pattern control or pattern management). As people with type 2 diabetes get older, it may become necessary to simplify complex insulin regimens because of a decline in self-management ability (see Section 13, “Older Adults”).
Disclosure information for each author is available at https://doi.org/10.2337/dc23-SDIS.
Suggested citation: ElSayed NA, Aleppo G, Aroda VR, et al., American Diabetes Association. 9. Pharmacologic approaches to glycemic treatment: Standards of Care in Diabetes—2023. Diabetes Care 2023;46(Suppl. 1):S140–S157
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https://elytraflight.com/blog/
|
Velocity Vectors: Secondary Solutions!
Hello, again! Encouraged by my sudden lack in homework and with interest in the problem at an all-time high, I decided to write a Part 2 about the idea of velocity vectors immediately! 😀
If you haven’t read the original post, I would highly suggest doing so first: https://elytraflight.com/2021/05/17/velocity-vectors-circles-and-calculus/ The main objective of this post is to go over two different approaches to the same problem, and to discuss their benefits and drawbacks. For now, however, let’s do this!
First, let’s reiterate the problem:
“A particle moves along a curve so that its position vector and velocity vector are perpendicular at all times. If the particle passes through the point (4, 3), what is the equation of the curve?”
Solution 2
In the previous post, we used a solution involving linear algebra, but who wants linear algebra? After all, linear algebra is just a bunch of funny number magic, right?
So, we decide to attack the problem an alternative way!
Consider what it means for two lines to be perpendicular. With two lines in the form of y = mx + b, the slopes have to be negative reciprocals of each other (e.g. 1/2 and -2 in the diagram below).
What does this mean for our problem? Let’s recall our position vector s(t) = (x(t), y(t)). The “slope” of our position vector, in this case, can be found with the general “rise over run” technique: m = (y-0)/(x-0) = y/x.
However, as we mentioned before, our velocity vector, v(t) = (x'(t), y'(t)), is perpendicular to the position vector! Thus, we know that the “slope” of our velocity vector, y'(t)/x'(t), is the negative reciprocal of y/x, which happens to be -x/y. So, this is what we end up with:
However, the second equality is more than just an equation; it’s a differential equation! A differential equation that we have the tools to solve, as a matter of fact!
Our first step is to separate the variables. We can move the dx to the right side and the y to the left side, to arrive at an equation as follows:
Time to integrate both sides!
Voila! We have arrived at the exact same answer as we did with the other method. Just like last time, we can plug in a specific case for x and y to find a specific case. Beautiful! 😀
Solution 3
And, last but not least, we have our final solution! Suppose we are still slightly suspicious of dot products, but we’re willing to give parametric functions (and some inefficient but cool techniques) a chance. Edit: After researching this solution a bit more, I realized that this solution gets crazy quite quickly. Buckle up!
Jumping right in, we reintroduce our vectors s(t) = (x(t), y(t)), and v(t) = (x'(t), y'(t)). However, this time we have a twist. This time, we don’t end up removing t to get a general form of the circle equation in terms of x and y. No; this time, we dig even deeper. What we intend to do today is find both x(t) and y(t) in general form.
In the above example, we see that we are taking advantage of a very important characteristic of perpendicular vectors. We take the x position, making it negative and multiplying by some constant a (as we do not want to assume that the velocity vector is the same magnitude as the position vector).
Note that we are multiplying by a constant value a. This will be important at the end.
So here’s the two equations we have so far:
x'(t) = a y(t)
y'(t) = -a x(t)
Let’s start by manipulating the first equation, moving a to the other side.
y(t) = x'(t)/a
Now, we take the derivative of both sides:
y'(t) = x”(t)/a
We now have two different formulas for y'(t). Let’s set them equal to each other!
x”(t)/a = -a x(t)
x”(t) = -a2x(t)
We now have a seemingly simple differential equation, with the second derivative in terms of the original function. However, we can’t just integrate, as that would leave us with a first derivative and some unruly antiderivative of x(t).
Our options are running out! With no options left, we have no choice but to put on our LaTeX gloves (hahaha I’m hilarious) and set out on a journey into Laplace Land.
Ahh, sunlight fills our eyes, and fresh air enters our lungs. At last, after all that pain and effort, here we are with our two final, completely general equations for x(t) and y(t):
And, you know what this means! If we find x2+y2, it will equal some constant not in terms of t, which is the radius of our new circle squared. Granted, this newly-found radius of the circle will be in terms of the given values for x(0), x'(0), and a, but that is to be expected.
Some of the incredibly astute may recall previously experimenting with piecewise functions, and how these trig functions are by no means the only two functions that can produce circles. For instance, something as simple as
can follow the path of a (semi)circle within its domain. Furthermore, parametric functions like these also satisfy the property of having position vectors and velocity vectors being perpendicular, since x2+y2=R; in the previous solutions, we demonstrated that this is enough to conclude that the velocity vector is always tangent to the position vector in such a scenario. However, our very complex-looking trigonometric formula up above is incredibly special, in that it is the only general case parametric function out there whose value for “a” stays constant everywhere. In other cases, such as x(t) = t, the two vectors are perpendicular, but the ratio in magnitudes varies wildly depending on t. In our above case, however, a stays constant. Everywhere.
If one is skeptical, we can test these formulas, and demonstrate that for any value of x(0) and x'(0) and a, the difference in magnitudes of the position and velocity vectors will indeed still be a, and by taking the derivatives of the formulas for x(t) and y(t) show that the formulas do indeed work out with what they should be. A true mathematical miracle.
This concludes the third and final solution to this amazing problem. What a crazy experience! This took me about 10 hours of work to finish, between the three different solutions. I now intend to rest for the time being.
It’s been an honor to have all of you readers along on this journey. As always, until we meet again, best wishes, and happy exploring!
– Ely
Velocity Vectors, Circles, and Calculus
Hello, everyone! While I have been drifting through my sea of homework, I came across a rather interesting problem involving circles and velocity vectors. The problem goes as follows:
“A particle moves along a curve so that its position vector and velocity vector are perpendicular at all times. If the particle passes through the point (4, 3), what is the equation of the curve?”
Building Intuition
Part of what makes the problem so interesting is our ability to come up with a general case, usable for any provided point of contact, and not just (4, 3)! First, let’s imagine what such a situation with perpendicular velocity and position vectors might look like.
One such possibility that fits the description would be a circle. As seen in the diagram, the velocity vectors v1, v2, and v3 (which happen to be tangent to the circle) are all perpendicular to their respective position vectors, r1, r2, and r3.
However, as we can soon see, there are multiple different (and rather beautiful) ways that we can prove that the only possible general curve is a circle!
Solution
Let’s do this! First things first, let’s describe our particle’s motion by describing it as a vector, where the x and y positions and x(t) and y(t) respectively, where t is time. We can write our position vector as s(t) = (x(t), y(t)).
What’s more, we can take the derivative of our position vector with respect to time to get a velocity vector! 😀 To accomplish that, all we need to do is take the derivative of the x and y positions separately. (Taking the derivative of a single-variable function f(t) results in f'(t), pronounced f prime of t. One might visualize the derivative as being the “rate of change” of a function, or how fast the function is changing at time t.)
v(t) = (x'(t), y'(t)).
From here, we can employ a neat trick from linear algebra known as the dot product. Essentially, the dot product helps us find the angle between two vectors. In this case, we know that the angle between our position vector (x(t), y(t)) and our velocity vector (x'(t), y'(t)) must be 90 degrees.
This is where the fun begins! One important aspect of the dot product, as we see on the bottom left, is that the dot product of perpendicular vectors is always 0. Thus, we can say that in all cases, s(t) · v(t) = 0.
The dot product of two vectors is calculated by summing the products of the same components of both vectors. For example, (3, 4) · (5, 6) = 3 * 5 + 4 * 6 = 15+24 = 39. However, (0, 2) · (3, 0) = 0 * 3 + 2 * 0 = 0. This makes sense, because (0, 2) and (3, 0) are perpendicular.
If we expand out s(t) · v(t) = 0, we get (x(t), y(t)) · (x'(t), y'(t)) = 0. If we expand this out using the above definition, we get that x(t) * x'(t) + y(t) * y'(t) = 0. This is cool, but how can we proceed from here? ANTIDERIVATIVES!
Indeed, if you noticed that the original functions are multiplied by their derivatives and were reminded of the chain rule, you would be onto something important. Because we have x(t) * x'(t), we are provided with a very clean antiderivative.
Now we have some math steps:
And we have it! Does the final equation look familiar? x2 + y2 = D, where D is the radius of the circle squared! In the above problem, we can plug in x(t) = 4 and y(t) = 3, and we get D = 9 + 16 = 25, meaning that the curve our particle is following is a circle with a radius of 5! 🙂
This post is running longer than I was originally intended, so I’ll make sure to write a Part 2 regarding the two other interesting ways of solving this problem if you’re interested. Until then, best wishes and happy exploring!
– Ely
Many thanks to my Calculus instructor, Ms. Nguyen, for inspiring me to write this post, as well as providing students with many different opportunities to succeed this year! For further explanation in regards to calculus and linear algebra, I would highly suggest checking out the amazing YouTube channel 3Blue1Brown for detailed and immersive visuals to help understand those sorts of topics on a deeper level! Here is his channel: https://www.youtube.com/channel/UCYO_jab_esuFRV4b17AJtAw You can also subscribe; it’s completely free, WordPress handles all of privacy concerns, and you get notified whenever something new comes out!
The Hardy-Weinberg Principle, and Mathematics within Biology
When we consider low-level biology courses, we may tend to think of more memorization-based concepts, such as the names of dozens of different organelles within a plant cell, as well as their various functions. In many cases, biology courses remain completely descriptive, removing any form of mathematics to avoid confusing the students any further than they already are. There are a few cases in biology, however, where instructors are required to introduce some mathematics to the curriculum; a welcome break from all the memorization required!
Consider a population of herbivorous moths, enjoying a sequestered life on a far-away island, with no predators to worry about and enough food to maintain a stable population of 1,000 moths. Inside the DNA of these moths resides a particular gene known as gene X. Gene X can have two different possible “variants”, capital A and lowercase a. Each moth cell has two copies of this gene, one from its mother and one from its father. As biologists, we know that the capital A variant corresponds to being a red-colored moth, and the lowercase a variant to being a blue-colored moth. The capital A variant is dominant over the other, meaning that if your father or mother gave you the red variant, you would also be a red moth. However, having two a variants results in a blue moth. These kinds of genes can be represented in a Punnett Square, as seen in the diagram below.
When two moths reproduce, one copy of the gene from each parent is contributed (at random) to create the child moth, leading to four possible equally-likely results. This concept of how genes are transmitted will help us understand the math behind the Hardy-Weinberg Principle.
Now that we understand the nature of how two individual moths reproduce, let’s zoom out to the bigger picture, considering the case of a population with 1,000 moths. Using our god-like omnipotence, we know that at this point in time there are a total of 1000 lowercase a gene variants in the population, and 1000 uppercase A variants. exactly 250 moths with two lowercase a variants, 250 moths with two uppercase A variants, and 500 with one uppercase A and one lowercase a. Following the Punnett Square logic seen above, it follows that both the 250 homozygous red moths (AA) and the 500 heterozygous moths (Aa) are red, resulting in a total of 250 + 500 = 750 red moths. Let’s unpack this information:
Awesome! We see that the totals gene variants add up correctly — There should be twice as many copies of the gene as there are moths, as every moth has 2 copies. This also highlights an important aspect of observing such populations. Although there are an equal amount of A and a variants in the population, 75% of the population is still red. Why is that?
Recall that the A variant is dominant. Any moths that have the Aa genotype are still completely red. One could say that some of the blue a variants are “wasted”, as they do not contribute to the color when the A variant is present.
Now that we have some of the background necessary, we can begin to explore the question of what the Hardy-Weinberg Principle actually tells us.
This may sound complicated, but we can break down this concept into more understandable terms. An allele is the scientific name for the different “variants” of a particular gene that we mentioned earlier. For instance, in our above example, the a and A variants are both examples of different alleles.
The term “allele frequency” refers to how many of each variant of the gene are present. For instance, the a allele’s frequency would be 50%, since 1000 of the 2000 alleles in the population are type a.
What does it mean for the allele frequencies to remain constant? Let’s consider the moth example again. Right now, we have a total of 1,000 moths, with 1,000 a alleles and 1,000 A alleles. Now, let’s say the moths have been reproducing a lot, and now there are 2,000 moths. Using the Hardy-Weinberg principle, we can also say there are now 2,000 a alleles and 2,000 A alleles. Furthermore, if there were 750 red moths and 250 blue moths, now there are 750 × 2 = 1,500 red moths, and 250 × 2 = 500 blue moths!
This may seem fairly straightforward. Twice as many moths, twice as many of each kind of moth. Simple algebra, right?
What makes Hardy-Weinberg so interesting, however, is that this neat pattern of multiplication only occurs under a specific set of circumstances — when the population is in Hardy-Weinberg Equilibrium.
There are a few requirements for a population to be in Hardy-Weinberg Equilibrium, but here are the main ones:
• Mate choice must be completely random. If Mr. Moth #295 has a particular affinity for Ms. Moth #296, tough luck. Everything must be random, otherwise we run the risk of mate selection rendering certain alleles “better” than others, which would disrupt the balance between the two alleles.
• As we mentioned above, having one allele must provide no advantage over having the other. If being blue makes it easier to survive or reproduce than being red, then over time there will be more blue moths, disrupting the balance.
• There must be no movement in or out of the population, or any other abnormal activity. That’s why our moths are on an island in the middle of nowhere; escapees or new visitors could also disrupt the balance.
• The population must be fairly large. In all cases, the Hardy-Weinberg principle deals with averages, not exact numbers. Perhaps a red moth eats a poisonous plant and dies, leaving behind 749 red moths and 250 blue moths. Although it isn’t ever exact, the ratio can still be treated as approximately 3:1. In an extreme example, if our population has a total of 4 moths, the chance of a random occurrence throwing off the balance gets to be extremely likely. This concept is known as genetic drift, an interesting topic in its own right.
Now that we understand what the Hardy-Weinberg Principle describes and under what criteria it occurs, how can we prove that this phenomenon would occur in this way? Now the math starts to get really interesting.
Let’s return again to our example of a population of 1,000 moths which we assume are in Hardy-Weinberg equilibrium. Let’s say this time, however, there are only 500 A alleles, and 1,500 a alleles. Punnett Square time!
At this point, our next step is to calculate the “expected” amount of alleles generated with a case of 16 baby moths. In math, to calculate the expected value we multiply the probability by the number of “trials”, in this case the 16 moths.
Since the Punnett Square has been reduced to one row and column, the math becomes a bit less complex. The probability of the child being AA is the probability of getting two A‘s in a row (because the population is large we can treat it as an independent event). In math, the probability of one event AND another event can be calculated by multiplying the probabilities. Since we know that 1/4 of the alleles are A in this case, the probability of getting two As is 1/4 × 1/4, or 1/16.
Likewise, the probability of being Aa is the same as getting either an A from the father and an a from the mother, OR getting an a from the father and an A from the mother. Since 1/4 of the alleles are A, and 3/4 of the alleles are a, and there are two ways of doing it, the probability is 2 × 1/4 × 3/4 = 3/8.
Finally, the probability of being aa is the probability of getting two a‘s in a row, or 3/4 × 3/4 = 9/16. From here, we can convert these probabilities to expected values, totaling the genotypes to find the expected values for each allele.
The expected value of AA genotypes will be 16 × 1/16 = 1. However, since the AA genotype contains two As, the expected value of A alleles from being AA will be 2. Next, since there is only 1 A allele in the Aa genotype, the expected value of A alleles from being Aa will be 16 × 3/8 = 6. Adding these together, we get that the total expected number of A alleles is 8! Following similar logic (that is a bit too long for the article), we get that the total expected number of a alleles is 24.
Voila! Just how the original ratio of A alleles to the total was 1:4, the expected ratio of A alleles in the 16 baby moths is also 1:4! When new moths were created, the allele ratio stayed the same. This, in essence, demonstrates the Hardy-Weinberg Principle. Complicated, but beautiful! The light at the end of the tunnel!
In summary, the Hardy-Weinberg principle states that whenever a population is in genetic equilibrium, any new organisms will always follow the same patterns as their predecessors.
Like always, there are many interesting questions left unanswered. What practical use does this concept have? What happens to a population that isn’t in genetic equilibrium? Rest assured there will be plenty of time to go over this at a future date. Until we meet again, best wishes and happy exploring!
– Ely
Many thanks to my biology instructor, Mr. Lewis, for introducing me to Hardy-Weinberg, and inspiring me to create this post! For further exploration, I would recommend checking out Khan Academy’s excellent article: https://www.khanacademy.org/science/ap-biology/natural-selection/hardy-weinberg-equilibrium/a/hardy-weinberg-mechanisms-of-evolution You can also subscribe; it’s completely free, WordPress handles all of privacy concerns, and you get notified whenever something new comes out! 🙂
Test
Hi! This is technically the first blog post on my website. I’m fairly new to WordPress, the service with which I am creating my blog, so this is only a trial run to see what happens when I create a blog post using their designated button. Have a good night, everyone! 🙂
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https://www.lessonplanet.com/teachers/points-of-intersection
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Points of Intersection
Eighth and ninth graders solve five different problems that include solving two equations. They determine the point of intersection in each of the five pairs of equations given. Pupils define point of intersection as the point where two lines cross with x and y coordinates on a graph.
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http://mathoverflow.net/questions/60957/how-to-determine-whether-an-ideal-is-prime-or-not-by-an-algorithm/60961
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# how to determine whether an ideal is prime or not by an algorithm
Given polynomials $f_{1},\cdots,f_{n}\in \mathbb{C}[x_{1},\cdots,x_{m}]$, do we have an algorithm to determine whether the ideal $I=(f_{1},\cdots,f_{n})$ is prime ideal or not? Of course, we assume the polynomials are irreducible.
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Macaulay2 has a function isPrime which tells you if an ideal is or not prime. – Mariano Suárez-Alvarez Apr 7 '11 at 15:59
Why do you assume that the polynomials are irreducible? – Qiaochu Yuan Apr 7 '11 at 16:36
to rule out the trivial case that its factors might not be in the ideal. – Jiang Apr 7 '11 at 17:28
It just doesn't seem to me that that assumption really helps. – Qiaochu Yuan Apr 8 '11 at 4:36
Let $R$ be a Noetherian ring and let $I$ be an ideal in $R[x]$. Then the following facts hold:
• $I$ is prime in $R[x]$ $\Longleftrightarrow$ $I\cap R$ is prime in $R$ and $\overline{I}$ is prime in $R/(R\cap I)$.
• If $R$ is an integral domain and $I \cap R=0$, then $I$ is prime in $R[x]$
$\Longleftrightarrow$ $I K[x]$ is prime in $K[x]$ and $I=IK[x] \cap K[x]$. Here $K$ denotes the fraction field of $R$.
Using the above to successively eliminate variables, this shows that one can reduce the problem of checking primiality to the one-variable case, where many efficient methods are known. I think this is also how the Grobner basis works, since these can algorithmically compute the elimination ideals above.
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Eliminate, eliminate, eliminate the eliminators of elimination theory... =) – Harry Gindi Apr 8 '11 at 6:05
There is such a test. Some explanation can be found in: "An introduction to Gröbner bases, By William Wells Adams, Philippe Loustaunau", or the original article (http://portal.acm.org/citation.cfm?id=65034) the above text is based on. See also the singular manual.
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Did you look into "A Singular Introduction to Commutative Algebra"?
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Buchberger's algorithm should do, Faugere's F4 is also one. However, this is generally for any ideal and not necessarily for irreducible. Is it something specific to irreducible polynomials that you are looking for?
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Irreducibility of the polynomials are not necessarily in my problem, what I need is just an algorithm to test the primality of a finite generated polynomial ideal. – Jiang Apr 8 '11 at 3:44
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https://www.lessonplanet.com/teachers/multiplying-by-zero-1st-2nd
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# Multiplying By Zero
In this multiplication by zero worksheet, students problem solve ten equations associated with multiplying by zero to equal the answer of zero.
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https://pos.sissa.it/316/013
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Volume 316 - XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects (DIS2018) - WG1: Structure Functions and Parton Densities
Determination and application of TMD parton densities using the Parton Branching method
A. Bermudez Martinez*, P.L.S. Connor, F. Hautmann, H. Jung, A.A. Lelek, V. Radescu and R. Zlebcik
Full text: pdf
Pre-published on: September 20, 2018
Published on: November 23, 2018
Abstract
We present a determination of parton densities at NLO obtained with the Parton Branching method using precision measurements of deep inelastic scattering cross sections at HERA. The two sets of parton densities shown in this work are obtained with the same angular angular ordering condition for the evolution scale and they differ in the chosen scale for the strong coupling evaluation, for which we consider two scenarios: the evolution scale, and the transverse momentum qT from the angular ordering prescription. The transverse momentum dependent densities obtained with the Parton Branching method are applied to two LHC processes: the Drell-Yan pT spectrum and the azimuthal correlation in high pT dijet events. For the Drell-Yan pT spectrum a significant effect from the strong coupling scale choice is observed.
DOI: https://doi.org/10.22323/1.316.0013
How to cite
Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.
Open Access
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http://aas.org/archives/BAAS/v26n2/aas184/abs/S2901.html
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Evidence for Homogeneous Ionization of Helium in the Local Interstellar Medium from EUVE Spectroscopy of Hot DA Stars
Session 29 -- General Interstellar Medium
Display presentation, Tuesday, 31, 1994, 9:20-6:30
## [29.01] Evidence for Homogeneous Ionization of Helium in the Local Interstellar Medium from EUVE Spectroscopy of Hot DA Stars
J.Dupuis, S.Vennes, S.Bowyer (CEA/UCB), A.K.Pradhan (OSU), P.Thejll (NBI)
We present an analysis of the Extreme Ultraviolet Explorer (EUVE) spectra of the DA stars Feige~24, MCT0455--281, HZ~43, GD~153, GD~71, and Sirius~B. This sample is selected on the basis of the stars' low interstellar hydrogen column densities and because of their widely separated Galactic coordinates. With the exception of Sirius~B, these stars all have a prominent He {\sc i} photoionization edge and a well defined Lyman continuum from which we derive reliable interstellar column densities of neutral hydrogen and neutral helium. For all the stars in the sample the measured abundance ratios of He\,{\sc i} \,:\,H\,{\sc i} differ significantly from the cosmic abundance ratio. We interpret these measurements in terms of ionization of helium in the local interstellar medium. The most striking result is that for all the Galactic lines of sight investigated, the relative ionization of helium is nearly constant with He~{\sc i}/H~{\sc i}$= 0.07 \pm 0.02$\,. This is similar to the result found for the hot DA GD~246 (Vennes et al. 1993, ApJ, 410, L119) for which a direct measurement of the He~{\sc ii} column was possible. The current sample probes various Galactic latitudes and longitudes and is indicative that helium is homogeneously ionized in the local interstellar medium.
In optical spectra all these stars exhibit a pure hydrogen atmosphere; in the EUV both Feige~24 and MCT0455--281 show a substantial number of metals. We do not find metals in the remainder of the objects reported here, and we provide stringent upper limits for He, C, N, and O in the photospheres of these stars. This work has been supported by NASA contract NAS5-30180.
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https://hsc-release.mtk.nao.ac.jp/doc/index.php/database/summary_table_usage-2/
|
# Summary Table Usage (PDR2)
## Summary Tables
Use summary tables, which we expect will satisfy most users’ need. In the summary tables, unlike other tables,
• Multiband data are available for each celestial object;
And,
• Fluxes are in [nJy] (changed from [erg cm-2 s-1 Hz-1] of PDR1); Magnitudes are also provided;
• Centroids are in (ra, dec);
• Shapes (quadrupole moments) are in arcseconds;
They are measured in the planes that contact the sky at the objects’ own positions.
These are not the case in other tables: Fluxes, for example, are not in a physical unit but are bare sums of values of pixels within objects’ areas.
There are two summary tables: meas and forced.
Contents in meas table were obtained from independent measurements of different bands. Forced table resulted from forced photometry.
The source files of meas table are “meas-###.fits”. The source files of forced tables are “forced_src-###.fits”.
We first explain the two in the following sections, and after that we show some use cases.
### meas
Contents in meas table were obtained from independent measurements of different bands. Meas table has been split into two tables (meas and meas2). This is due to a technical limit of PostgreSQL. It forbids a table more than around 1600 columns. If you want aperture fluxes or their flags, you have to join the two tables. Thus:
SELECT
object_id, i_ra, i_dec, i_apertureflux_10_mag, g_apertureflux_10_mag
FROM
pdr2_wide.meas LEFT JOIN pdr2_wide.meas3 USING (object_id)
WHERE
-- (ra, dec) = (33 deg, -3.5 deg), radius = 60 arcsec.
coneSearch(i_coord, 33, -3.5, 60)
;
If you do not need any fields in meas2 table, you can omit meas2 from the FROM-clause, but you do not have to — Unnecessary tables joined will not affect response performance.
Note:
• Meas table doesn’t have (ra,dec) fields, but it has fields of band-specific positions: (gra, gdec), (rra, rdec), (ira, idec), (zra, zdec), (yra, ydec), etc.
### forced
Forced table resulted from forced photometry. It is easier to use forced table than meas table, for everything is in one table, unlike meas table:
SELECT
object_id, ra, dec, i_apertureflux_10_mag, g_apertureflux_10_mag
FROM
pdr2_wide.forced LEFT JOIN pdr2_wide.forced3 USING (object_id)
WHERE
-- (ra, dec) = (33 deg, -3.5 deg), radius = 60 arcsec.
coneSearch(coord, 33, -3.5, 60)
;
Note:
• Forced table have (ra, dec) fields common to all bands since in forced photometry, objects’ positions were shared by measurements of different bands.
## Basic usage
Example:
SELECT
object_id, ra, dec, g_cmodel_mag, r_cmodel_mag, i_cmodel_mag
FROM
pdr2_dud.forced
WHERE
-- Equivalent to "tract = 8524", but tractSearch() is by far the faster.
tractSearch(object_id, 8524)
AND isprimary
;
• object_id is the unique ID number for each object. It is a 64-bit integer. Be careful not to ruin it by converting it to 32-bit integer or 32/64-bit float. For instance, opening a CSV file by Microsoft Excel will damage object_id. For advanced users: object_id is called simply “id” in source catalogs output by the analysis pipeline. In other tables, object_id field is named id without difference in its meanings and values.
• Multiband fields are prefixed with filter names. For example, g_cmodel_mag is “Magnitude by cmodel algorithm in g-band”
• Fields not prefixed with filter names are common to all bands.
The summary tables have the following columns that are prepared specially for display, or in other words, for use in SELECT-clause. It is not recommended that they are used in search criteria.
ra, dec; g_ra, g_dec; r_ra, r_dec; i_ra, i_dec,…
These fields are computed from coord, g_coord and so on, on the fly.
tract, patch
These fields are computed from skymap_id on the fly. Patch is an integer value that can be decomposed into patch_x and patch_y by “patch = 100*patch_x + patch_y”.
The summary tables have the following columns that are prepared specially for search criteria. They are not intended to be selected in SELECT-clauses.
coord; g_coord, r_coord, i_coord,…
These fields essentially contain the same information as (ra,dec), but are used only for search criteria. Thus:
WHERE boxSearch(coord, 33, 34, -3, -4).
This is equivalent to “WHERE (ra BETWEEN 33 AND 34) AND (dec BETWEEN -4 AND -3)”, but the former is significantly faster. “Coord” is in forced table, while “g_coord” etc. are in meas table.
There are special condition functions that accelerate queries, as shown below. It is recommended that at least one of them is included in WHERE-clauses. Otherwise, your queries will not return in the time limit.
boxSearch(coord, ra1, ra2, dec1, dec2) → boolean
This function searches for objects within the box
[ra1, ra2] × [dec1, dec2].
For the first argument coord, one of fields “coord”, “g_coord”, “r_coord”, etc., must be passed in. The other arguments are in degrees.
Example: boxSearch(coord, 33, 34, -3, -4)
conesearch(coord, ra, dec, radius) → boolean
This function searches for objects within the cone centered at (ra, dec) with its radius radius.
For the first argument coord, one of fields “coord”, “g_coord”, “r_coord”, etc., must be passed in. RA and Dec are in degrees. Radius is in arcseconds.
Example: coneSearch(i_coord, 33, -3.5, 60)
tractSearch(object_id, tract) → boolean
This function searches for objects within the tract tract. For the first argument object_id, the field “object_id” must be passed in.
Example: tractSearch(object_id, 8524)
tractSearch(object_id, tractStart, tractEnd) → boolean
This function searches for objects within the tracts from tractStart through tractEnd inclusive. For the first argument object_id, the field “object_id” must be passed in.
Example: tractSearch(object_id, 8522, 8526)
## Practical use cases
### Get clean objects from COSMOS Deep / Ultra Deep Field
SELECT
object_id, ra, dec,
-- cmodel fluxes
g_cmodel_flux, g_cmodel_fluxsigma,
r_cmodel_flux, r_cmodel_fluxsigma,
i_cmodel_flux, i_cmodel_fluxsigma,
z_cmodel_flux, z_cmodel_fluxsigma,
y_cmodel_flux, y_cmodel_fluxsigma,
-- PSF fluxes
g_psfflux_flux, g_psfflux_fluxsigma,
r_psfflux_flux, r_psfflux_fluxsigma,
i_psfflux_flux, i_psfflux_fluxsigma,
z_psfflux_flux, z_psfflux_fluxsigma,
y_psfflux_flux, y_psfflux_fluxsigma,
-- Galaxy or star?
i_extendedness_value,
-- Absorptions
a_g, a_r, a_i, a_z, a_y
FROM
pdr2_dud.forced
JOIN pdr2_dud.forced2 USING (object_id)
WHERE
-- Search 2 degrees around (ra,dec) = (150, 2)
coneSearch(coord, 150, 2, 2*3600)
-- Primary object (see below) only
AND isprimary
-- Forced-measurement was done with reference to i-band
AND merge_measurement_i
-- Centroid algorithm succeeded in all bands
AND NOT g_sdsscentroid_flag
AND NOT r_sdsscentroid_flag
AND NOT i_sdsscentroid_flag
AND NOT z_sdsscentroid_flag
AND NOT y_sdsscentroid_flag
-- CModel flux algorithm succeeded in all bands
AND NOT g_cmodel_flag
AND NOT r_cmodel_flag
AND NOT i_cmodel_flag
AND NOT z_cmodel_flag
AND NOT y_cmodel_flag
-- Not at the edges of images
AND NOT g_pixelflags_edge
AND NOT r_pixelflags_edge
AND NOT i_pixelflags_edge
AND NOT z_pixelflags_edge
AND NOT y_pixelflags_edge
-- Center 3x3 pixels are not interpolated
AND NOT g_pixelflags_interpolatedcenter
AND NOT r_pixelflags_interpolatedcenter
AND NOT i_pixelflags_interpolatedcenter
AND NOT z_pixelflags_interpolatedcenter
AND NOT y_pixelflags_interpolatedcenter
-- Center 3x3 pixels are not saturated
AND NOT g_pixelflags_saturatedcenter
AND NOT r_pixelflags_saturatedcenter
AND NOT i_pixelflags_saturatedcenter
AND NOT z_pixelflags_saturatedcenter
AND NOT y_pixelflags_saturatedcenter
-- Center 3x3 pixels are not contaminated by cosmic rays
AND NOT g_pixelflags_crcenter
AND NOT r_pixelflags_crcenter
AND NOT i_pixelflags_crcenter
AND NOT z_pixelflags_crcenter
AND NOT y_pixelflags_crcenter
-- Not on bad pixels of CCDs
-- Get first 100 records only, for preview.
-- Remove this limit to get the whole result.
LIMIT 100
;
This is a straightforward extension from the basic usage above.
If objects are primary objects (as demanded in the WHERE-clause), they are:
• Isolated objects or deblended children, and
• Within inner patches and inner tracts.
Inner patches / inner tracts:
In mosaicking, the sky was split into regions called tracts, and for each tract its sky region was projected onto a plane. The plane is called a tract, too. The plane was further split into fragments of modest size called patches. A problem here is that the tracts an patches are defined with slight overlaps with each other. Objects in the overlapping regions appears twice or more in the catalog table. “Inner patches / inner tracts” are literally inner regions within patches and tracts, and defined such that they are adjacent to each other without overlaps. You can avoid object duplication by requiring the objects are within inner patches and inner tracts.
Flags indicates failure in general. To get “clean” catalogs, you have to check them to be FALSE. You should bear in mind that logic is tristate in SQL: a flag may be TRUE, FALSE, or UNKNOWN (also called NULL).
Thus:
“TRUE = UNKNOWN” → UNKNOWN;
“UNKNOWN and TRUE” → UNKNOWN;
but “UNKNOWN or TRUE” → TRUE.
Aside from these usual logical operators, there are six postpositional operators that must be used carefully: IS TRUE, IS FALSE, IS UNKNOWN, and their negation IS NOT TRUE etc. Values of these six will never be UNKNOWN but will always be TRUE/FALSE. For example, “UNKNOWN is not false” → TRUE while “UNKNOWN != false” → UNKNOWN. Beware of the difference or you may get an unintended result.
LIMIT 100” is required before you push ‘preview’ button in the Direct SQL Search Form. If the preview times out, press the ‘preview’ button again and again until it succeeds. In the process, data will gradually be loaded from hard disks onto memory, and finally the preview will succeed in time — probably for the example above, but do not assume this is the case in general.
### Match your catalog with the summary tables
If your catalog is small (around 10,000 records), you can match it with the summary tables in this way:
WITH
-- Describe the catalog to match
my_catalog(my_id, my_ra, my_dec, my_mag) AS (VALUES
-- Specify data types here
(NULL::int8, NULL::float8, NULL::float8, NULL::float4),
-- Then list records to match
(37484559004079282, 34.9368103756283, -5.49575920878389, 25.8668),
(37484559004079399, 34.9376518156381, -5.49356595402835, 25.4748),
(37484559004079428, 34.9461145648192, -5.49299547939153, 25.2956),
(37484559004079718, 34.9377573698323, -5.48685133433986, 25.4888),
-- :
-- : (10,000 records)
-- :
(37484705032992272, 34.8390549872623, -5.23730251854975, 24.7598)
)
,
-- Create the match catalog which contain minimal required information
match AS (
SELECT
my_catalog.*,
object_id
-- No columns should be selected other than "object_id"
-- To obtain other columns, describe them in the principal clause below
FROM
my_catalog JOIN pdr2_wide.meas ON (
-- Positions within 1.0 arcseconds
coneSearch(i_coord, my_ra, my_dec, 1.0)
)
-- No WHERE-clause should exist here
)
-- The principal clause:
-- Filter the above match catalog by conditions
-- and select columns other than object_id
SELECT
match.*,
i_ra, i_dec, i_cmodel_mag
FROM
match JOIN pdr2_wide.meas USING (object_id)
WHERE
i_detect_isprimary
;
This query looks complicated and is actually complex in a grammatical sense. It is composed of two subordinate clauses, my_catalog and match, and a principal clause. Thus:
WITH my_catalog ..., match ... SELECT ...;
First, you have to create your own catalog to match: my_catalog. You can use “VALUES (a, b, c), (d, e, f),…” construct for this purpose.
Then, you create a match catalog: “match”. Matching will be done without special tricks — for each record in my_catalog, the summary table is searched for matching records. It is desirable that this process is performed quickly, and so this clause (“match AS (…)”) should be as simple as possible. You should not select columns other than object_id from the summary tables, and you should not describe a WHERE-clause here.
Finally, select wanted columns and sift out clean records in the principal clause.
You should note that the resulting matches are not one-on-one. If there are two or more objects in one catalog within the search radius from an object in another, all the pairs are included in the match catalog.
## Notes on invalid values
In the summary tables, invalid values are represented by 'NaN' (Not a Number).
For people unfamiliar to computer science, behaviors of NaN look strange at first glance, but PostgreSQL treats 'NaN' still more surprising manner. Read this section carefully even if you are familiar with NaN.
### Common knowledge on NaN
Usually (but not necessarily in PostgreSQL), NaN implies “unknown”. Therefore,
• “NaN = NaN” is false. (NaN is not equal to itself)
• “NaN != NaN” is true.
• “NaN > 1” is false, “NaN = 1” is false, and “NaN < 1” is also false.
We must emphasize again that the rules above are not necessarily the case in PostgreSQL, but once you get catalogs and you open them with C/C++ programs, python scripts, or any other tools, then NaN will behave like this.
### Peculiarities of NaN in PostgreSQL
In PostgreSQL, 'NaN' is ordered:
• “NaN = NaN” is true.
• “NaN != NaN” is false.
• “NaN > 1” is true, “NaN = 1” is false, and “NaN < 1” is false.
In fact, 'NaN' is the largest number of all, larger than 'Infinity'.
Let us consider a criterium r_kronflux_mag - i_kronflux_mag > 1:
r_kronflux_mag i_kronflux_mag r_kronflux_mag - i_kronflux_mag r_kronflux_mag - i_kronflux_mag > 1
NaN (other value) NaN True
(other values) NaN NaN True
NaN NaN NaN True
The criterium above will admit such objects that i-band magnitude is faint (NaN). It may not be your intention. Perhaps what you need is:
r_kronflux_mag - i_kronflux_mag > 1 AND i_kronflux_mag != 'NaN'.
A tricky solution is to move i_kronflux_mag to the right hand side:
r_kronflux_mag i_kronflux_mag r_kronflux_mag > i_kronflux_mag + 1
NaN (other value) True
(other values) NaN False
NaN NaN False
In astronomy, as an object gets fainter, its magnitude gets larger. If the object gets even fainter, the magnitude will finally be NaN. Fortunately this fact is consistent with PostgreSQL’s treatment of NaN that NaN is larger than any other number.
## Help() function
There is help() function in the database. You can get descriptions of tables, columns, and functions like:
SELECT * FROM help('pdr2_dud.%');
SELECT * FROM help('pdr2_dud.meas');
SELECT * FROM help('pdr2_dud.meas%.i_%shape_%');
SELECT * FROM help('%search');
‘%’ is the wildcard. It is not ‘*’. Basically all you need is this one special character, but if you want details, google “postgresql similar to”
You can further exploit help() function to find tables that contain specific columns:
SELECT * FROM help('pdr2_%.%.n921_sdssshape%');
## Appendix
### Independent measurements
The contents in meas table were the output of independent measurements.
Independent measurements were, in contrast to forced photometry, done independently in different bands. You should however note that the measurements were not totally independent. We explain it in the following paragraphs.
The measurement process began with peak detection in each band. It occurred independently.
Second, the peaks in all bands were collected to make a pan-band peak catalog. Peaks in different bands but sufficiently close in position were merged here. The flags merge_peak_g, merge_peak_r, etc. will tell you what bands a peak came from. A peak may come from two or more bands, in which case it was a merged peak.
Third, each band was measured with the use of the pan-band peak catalog. Though peak positions as initial values were common to all bands, measurements (deblend, centroid, flux, shape,…) were done independently of the other bands. Deblending did not create new children: the process only determined distribution of photon flux to existing peaks.
Independent measurements that we call here are this third stage of the measurement process. The outcome from the third stage are stored in meas table.
### Forced photometry
The contents in forced table resulted from forced photometry. Let us explain its difference from independent measurements.
After the three stages above, the measurement proces still went on.
Fourth, the catalogs from the third stage were collected to make a reference catalog with which to perform forced photometry. This merge was different from the second stage in nature: for each object, the process chose the first record that had sufficient flux S/N, among the bands from which the peak had actually come from, in the order of a pre-defined priority. The reference catalog resulted from this procedure. The flags merge_measurement_g, merge_measurement_r, etc. will tell you what band a reference record came from.
Fifth, forced photometry was performed on each band with the reference catalog. In this stage, some parameters (centroid and ellipticities) in flux measurements were not free but fixed as the reference. Note centroids and shapes were actually re-measured, but these new values were not used in flux measurements.
The outcome from the fifth stage are stored in forced table.
|
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|
https://mersenneforum.org/showthread.php?s=9e084c59c264159c360a322148d3d472&t=17969
|
mersenneforum.org Android app recommendations
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2013-03-16, 05:42 #1 Uncwilly 6809 > 6502 """"""""""""""""""" Aug 2003 101×103 Posts 918510 Posts Android app recommendations Got myself an android tablet. Looking to find some good apps. Especially a nice calculator app. What are your faves?
2013-03-16, 06:06 #2 frmky Jul 2003 So Cal 2·13·79 Posts RealCalc. Supports RPN.
2013-03-16, 13:07 #3 Mini-Geek Account Deleted "Tim Sorbera" Aug 2006 San Antonio, TX USA 17×251 Posts 250+ Solitaire Collection and Sudoku Free are good simple puzzlers, if you like that sort of thing.
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2020-08-22, 22:41 #6 ewmayer ∂2ω=0 Sep 2002 República de California 22·3·5·193 Posts As is well-known hereabouts, the only smartphones I have ever owned are some cracked-screen Android ones I installed a Linux-environment freeware app on in order to run my Mlucas code. Said Linux distro of course includes Linux bc, which one can use as a text-based calculator app ... pretty basic, decimal-math based so noticeably slow once operands get beyond a few hundred digits in length ... but allows one to write one's own code to add functionality as needed and do cool stuff. For example, below is a sample of code I simply paste into an integer-mode bc run (floating-point-emulation mode needs 'bc -l' and possibly fiddling of the 'scale' setting) to give me some useful basic number-theory functionality. Never used an Android tablet, though, and anyway, as you can see I'm either a weirdo or a Luddite when it comes to app-tech. :) Code: define abs(n) { if(n < 0) return(-n); return(n); } define trailz(n) { auto ssave, i; i = 0; while(n && !(n%2)) { i += 1; n /= 2; } /* Bizarre: (n%2 == 0) didn't work here */ return(i); } define bits(n) { auto ssave, r; ssave = scale; scale = 0; /* In case we're in floating-point mode */ r = length(n)*3321928095/1000000000; while ( 2^r > n ) { r -= 1; } scale = ssave; return(r+1); } define reverse(n,nbits) { auto ssave, tmp; ssave = scale; scale = 0; /* In case we're in floating-point mode */ tmp = 0; while(nbits) { tmp = 2*tmp + (n % 2); n /= 2; nbits -= 1; } scale = ssave; return(tmp); } /* If the input == 2^p, return lg(n), otherwise return -1. Note: We do not consider 0 as being a power of 2, since there is no number x such that 2^x = 0. No special casing is needed for 0, since bits(0) = trailz(0) = 0. */ define ispow2(n) { auto bt, tz; bt = bits(n); tz = trailz(n); if(bt == tz+1) return(tz); return(-1); } /* left-to-right binary modpow, a^b (mod n); note that special 'fast' version which assumes user knows what he is doing and eschews input corner-case checking was not faster for me in practice: */ define modpow_lr(a,b,n) { auto ssave, y,len; ssave = scale; scale = 0; /* In case we're in floating-point mode */ /* For n = 0, trigger a div-by-0 error; for n = +-1 return 0: */ if(abs(n) < 2) { scale = ssave; return 2%n; } /* For b = 0, return 1; for b < 0, return 0: */ if(b <= 0) { scale = ssave; return(b==0); } /* For a = 0, return 0; for a = +-1 return a^(b%2): */ if(abs(a) < 2) { scale = ssave; return (a!=0) * a^(b%2); } len = bits(b); b = reverse(b,len); /*print "modpow_lr: n = ",n,", #bits = ",len,", reverse = ",b,"\n";*/ y = a%n; b /= 2; while(--len) { y = (y*y)%n; if(b%2) y = (a*y)%n; /*print "len = ",len,", bit = ",b%2,": y = ",y,"\n";*/ b /= 2; } scale = ssave; return(y); } /* right-to-left-to-right binary modpow, a^b (mod n): */ define modpow_rl(a,b,n) { auto ssave, y,z; ssave = scale; scale = 0; /* In case we're in floating-point mode */ /* For n = 0, trigger a div-by-0 error; for n = +-1 return 0: */ if(abs(n) < 2) { scale = ssave; return 2%n; } /* For b = 0, return 1; for b < 0, return 0: */ if(b <= 0) { scale = ssave; return(b==0); } /* For a = 0, return 0; for a = +-1 return a^(b%2): */ if(abs(a) < 2) { scale = ssave; return (a!=0) * a^(b%2); } y = 1; z = a%n; while(b) { if(b%2) y = (y*z)%n; z = (z*z)%n; b /= 2; } scale = ssave; return(y); } /* base-2 specialized version of modpow_lr, computes 2^b (mod n): */ define modpow_lr2(b,n) { auto ssave, i,y,len; ssave = scale; scale = 0; /* In case we're in floating-point mode */ len = bits(b); i = len; while(--i) { bmap[i] = (b%2); b /= 2; } y = 2; i = 1; /* No need to mod until y >= n: */ while(i < len) { y = (y*y); if(bmap[i++]) { y += y; } if(y >= n) break; } y = y%n; while(i < len) { y = (y*y)%n; if(bmap[i++]) { y += y; if(y >= n) y -= n; } } scale = ssave; return(y); } /* Single-modpow timing test: p = 3217; n = 2^p-1; modpow_lr2(n-1,n) */ /* returns 1 if p is a base-z Fermat pseudoprime, 0 otherwise. */ define pprimef(p,base) { y = modpow_lr(base,p-1,p); return(y==1); } define isprp(p) { auto ssave; ssave = scale; scale = 0; /* In case we're in floating-point mode */ if(p == 2) { scale = ssave; return(1); } if(!(p%2)) { scale = ssave; return(0); } /* Must only use inputs > the largest pprimef-base used below ... better, use that 341 is the smallest base-2 Fermat-pseudoprime: */ if(p < 341) { scale = ssave; return(pprimef(p,2)); } scale = ssave; return(pprimef(p,2) && pprimef(p,3) && pprimef(p,5) && pprimef(p,7) && pprimef(p,11) && pprimef(p,13)); } define find_next_prp(n,up_or_down) { auto i,j,d; /* direction properly specified? */ if(abs(up_or_down) != 1) { print "Direction of search not properly specified, must = +1 (up) or -1 (down).\n"; return(0); } d = 2*up_or_down; /* n must be odd: */ if(!(n%2)) { n -= up_or_down; print "Made n odd, starting search with: ",n,"...\n"; } i = 0; j = 0; while(1) { n += d; i += 1; if(pprimef(n,2)) { j += 1; if(isprp(n)) { print "[",i," odds tried, ",j," of which were 2-PRPs] Found next PRP: ",n,"\n"; return(n); } } } } define gcd(x,y) { auto ssave, q, f; ssave = scale; scale = 0; /* In case we're in floating-point mode */ if(!y) { scale = ssave; return(x); } while(y) { q = x/y; /* Find quotient of current x/y and round toward zero: */ f = x - q*y;/* Find y' and store in temporary: */ x = y; /* Find x', i.e. move the old value of y into the slots for x: */ y = f; /* New value of y: */ } scale = ssave; return(x); }
2020-08-23, 09:57 #7 M344587487 "Composite as Heck" Oct 2017 3×5×72 Posts F Droid is a must, it's a repo for FOSS apps ( https://en.wikipedia.org/wiki/F-Droid ). Shattered Pixel Dungeon is a roguelike that works well with a touch screen. There are various ssh and terminal emulators to interact with your tablet in a Linuxy way.
2020-08-26, 21:35 #8 Mark Rose "/X\(‘-‘)/X\" Jan 2013 24×3×61 Posts Wolfram Alpha can be handy. If you're looking for a fun and simple game, check out Flow Free.
2020-08-27, 08:46 #9
kruoli
"Oliver"
Sep 2017
Porta Westfalica, DE
19616 Posts
Quote:
Originally Posted by Mark Rose Wolfram Alpha can be handy.
That would be a "Wortwitz" in German. "Handy" means "mobile phone".
It is really nice that this paid version has a lot of the features you would only get for some monthly subscription on the website, so I use it rather often. Also, the extended keyboard with a lot of mathematical symbols is handy on a "Handy".
2020-09-09, 12:04 #10 pinhodecarlos "Carlos Pinho" Oct 2011 Milton Keynes, UK 484610 Posts Hope I can use this thread to ask for a good iPhone spam call blocker.
2020-10-07, 10:54 #11 R2357 "Ruben" Oct 2020 Nederland 1001102 Posts Apps Primes, Primes between Numbers and Big Integer Calculater
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http://stats.stackexchange.com/questions/102806/does-correlation-also-mean-the-slope-in-regression-analysis
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# Does “correlation” also mean the slope in regression analysis?
I'm reading a paper and the author wrote:
The effect of A,B, C on Y was studied through the use of multiple regression analysis. A,B,C were entered into the regression equation with Y as the dependent variable. The analysis of variance is presented in Table 3. The effect of B on Y was significant, with B correlating .27 with Y.
English is not my mother tongue and I got really confused here.
First, he said he would run a regression analysis, then he showed us the analysis of variance. Why?
And then he wrote about the correlation coefficient, is that not from correlation analysis? Or this word could also be used to describe regression slope?
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First, he said he would run a regression analysis, then he showed us the analysis of variance. Why?
Analysis of variance (ANOVA) is just a technique comparing the variance explained by the model versus the variance not explained by the model. Since regression models have both the explained and unexplained component, it's natural that ANOVA can be applied to them. In many software packages, ANOVA results are routinely reported with linear regression. Regression is also a very versatile technique. In fact, both t-test and ANOVA can be expressed in regression form; they are just a special case of regression.
For example, here is a sample regression output. The outcome is miles per gallon of some cars and the independent variable is whether the car was domestic or foreign:
Source | SS df MS Number of obs = 74
-------------+------------------------------ F( 1, 72) = 13.18
Model | 378.153515 1 378.153515 Prob > F = 0.0005
Residual | 2065.30594 72 28.6848048 R-squared = 0.1548
Total | 2443.45946 73 33.4720474 Root MSE = 5.3558
------------------------------------------------------------------------------
mpg | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
1.foreign | 4.945804 1.362162 3.63 0.001 2.230384 7.661225
_cons | 19.82692 .7427186 26.70 0.000 18.34634 21.30751
------------------------------------------------------------------------------
You can see the ANOVA reported at top left. The overall F-statistics is 13.18, with a p-value of 0.0005, indicating the model being predictive. And here is the ANOVA output:
Number of obs = 74 R-squared = 0.1548
Root MSE = 5.35582 Adj R-squared = 0.1430
Source | Partial SS df MS F Prob > F
-----------+----------------------------------------------------
Model | 378.153515 1 378.153515 13.18 0.0005
|
foreign | 378.153515 1 378.153515 13.18 0.0005
|
Residual | 2065.30594 72 28.6848048
-----------+----------------------------------------------------
Total | 2443.45946 73 33.4720474
Notice that you can recover the same F-statistics and p-value there.
And then he wrote about the correlation coefficient, is that not from correlation analysis? Or this word could also be used to describe regression slope?
Assuming the analysis involved using only B and Y, technically I would not agree with the word choice. In most of the cases, slope and correlation coefficient cannot be used interchangeably. In one special case, these two are the same, that is when both the independent and dependent variables are standardized (aka in the unit of z-score.)
For example, let's correlate miles per gallon and the price of the car:
| price mpg
-------------+------------------
price | 1.0000
mpg | -0.4686 1.0000
And here is the same test, using the standardized variables, you can see the correlation coefficient remains unchanged:
| sdprice sdmpg
-------------+------------------
sdprice | 1.0000
sdmpg | -0.4686 1.0000
Now, here are the two regression models using the original variables:
. reg mpg price
Source | SS df MS Number of obs = 74
-------------+------------------------------ F( 1, 72) = 20.26
Model | 536.541807 1 536.541807 Prob > F = 0.0000
Residual | 1906.91765 72 26.4849674 R-squared = 0.2196
Total | 2443.45946 73 33.4720474 Root MSE = 5.1464
------------------------------------------------------------------------------
mpg | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
price | -.0009192 .0002042 -4.50 0.000 -.0013263 -.0005121
_cons | 26.96417 1.393952 19.34 0.000 24.18538 29.74297
------------------------------------------------------------------------------
... and here is the one with standardized variables:
. reg sdmpg sdprice
Source | SS df MS Number of obs = 74
-------------+------------------------------ F( 1, 72) = 20.26
Model | 16.0295482 1 16.0295482 Prob > F = 0.0000
Residual | 56.9704514 72 .791256269 R-squared = 0.2196
Total | 72.9999996 73 .999999994 Root MSE = .88953
------------------------------------------------------------------------------
sdmpg | Coef. Std. Err. t P>|t| [95% Conf. Interval]
-------------+----------------------------------------------------------------
sdprice | -.4685967 .1041111 -4.50 0.000 -.6761384 -.2610549
_cons | -7.22e-09 .1034053 -0.00 1.000 -.2061347 .2061347
------------------------------------------------------------------------------
As you can see, the slope of the original variables is -0.0009192, and the one with standardized variables is -0.4686, which is also the correlation coefficient.
So, unless the A, B, C, and Y are standardized, I would not agree with the article's "correlating." Instead, I'd just opt of a one unit increase in B is associated with the average of Y being 0.27 higher.
In more complicated situation, where more than one independent variable is involved, the phenomenon described above will no longer be true.
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Excellent exposition. – bdeonovic Jun 10 '14 at 13:44
First, he said he would run a regression analysis, then he showed us the analysis of variance. Why?
The analysis of variance table is a summary of part of the information you can get from regression. (What you may think of as an analysis of variance is a special case of regression. In either case you can partition the sums of squares into components that can be used to test various hypotheses, and this is called an analysis of variance table.)
And then he wrote about the correlation coefficient, is that not from correlation analysis? Or this word could also be used to describe regression slope?
The correlation is not the same thing as regression slope, but the two are related. However, unless they left a word (or perhaps several words) out, the pairwise correlation of B with Y doesn't tell you directly about the significance of the slope in the multiple regression. In a simple regression, the two are directly related, and such a relationship does hold. In multiple regression partial correlations are related to slopes in the corresponding way.
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I am providing codes in R just an example, you can just see answers if you do not have experience with R. I just want to make some cases with examples.
correlation vs regression
Simple linear correlation and regression with one Y and one X:
The model:
y = a + betaX + error (residual)
Let's say we have only two variables:
X = c(4,5,8,6,12,15)
Y = c(3,6,9,8,6, 18)
plot(X,Y, pch = 19)
On a scatter diagram, the closer the points lie to a straight line, the stronger the linear relationship between two variables.
Let's see linear correlation.
cor(X,Y)
0.7828747
Now linear regression and pull-out R squared values.
reg1 <- lm(Y~X)
summary(reg1)$r.squared 0.6128929 Thus coefficients of the model are: reg1$coefficients
(Intercept) X
2.2535971 0.7877698
The beta for X is 0.7877698. Thus out model will be:
Y = 2.2535971 + 0.7877698 * X
Square root of the R-squared value in regression is same as r in linear regression.
sqrt(summary(reg1)$r.squared) [1] 0.7828747 Let's see scale effect on regression slope and correlation using the same above example and multiply X with a constant say 12. X = c(4,5,8,6,12,15) Y = c(3,6,9,8,6, 18) X12 <- X*12 cor(X12,Y) [1] 0.7828747 The correlation remain unchanged as do R-squared. reg12 <- lm(Y~X12) summary(reg12)$r.squared
[1] 0.6128929
reg12$coefficients (Intercept) X12 0.53571429 0.07797619 You can see the regression coefficients changed but not R-square. Now another experiment lets add a constant to X and see what this will have effect. X = c(4,5,8,6,12,15) Y = c(3,6,9,8,6, 18) X5 <- X+5 cor(X5,Y) [1] 0.7828747 Correlation is still not changed after adding 5. Let's see how this will have effect on regression coefficients. reg5 <- lm(Y~X5) summary(reg5)$r.squared
[1] 0.6128929
reg5$coefficients (Intercept) X5 -4.1428571 0.9357143 The R-square and correlation do not have scale effect but intercept and slope do. So slope is not same as correlation coefficient (unless variables are standardized with mean 0 and variance 1). what is ANOVA and Why we do ANOVA ? ANOVA is technique where we compare variances to make decisions. The response variable (called Y) is quantitative variable while X can quantitative or qualitative (factor with different levels). Both X and Y can be one or more in number. Usually we say ANOVA for qualitative variables, ANOVA in regression context is less discussed. May be this may be cause of your confusion. The null hypothesis in qualitative variable (factors eg. groups) is that mean of groups is not different / equal while in regression analysis we test whether slope of line is significantly different from 0. Let's see an example where we can do both regression analysis and qualitative factor ANOVA as both X and Y are quantitative, but we can treat X as factor. X1 <- rep(1:5, each = 5) Y1 <- c(12,14,18,12,14, 21,22,23,24,18, 25,23,20,25,26, 29,29,28,30,25, 29,30,32,28,27) myd <- data.frame (X1,Y1) The data looks like follows. X1 Y1 1 1 12 2 1 14 3 1 18 4 1 12 5 1 14 6 2 21 7 2 22 8 2 23 9 2 24 10 2 18 11 3 25 12 3 23 13 3 20 14 3 25 15 3 26 16 4 29 17 4 29 18 4 28 19 4 30 20 4 25 21 5 29 22 5 30 23 5 32 24 5 28 25 5 27 Now we do both regression and ANOVA. First regression: reg <- lm(Y1~X1, data=myd) anova(reg) Analysis of Variance Table Response: Y1 Df Sum Sq Mean Sq F value Pr(>F) X1 1 684.50 684.50 101.4 6.703e-10 *** Residuals 23 155.26 6.75 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 reg$coefficients
(Intercept) X1
12.26 3.70
Now conventional ANOVA (mean ANOVA for factor/qualitative variable) by converting X1 to factor.
myd$X1f <- as.factor (myd$X1)
regf <- lm(Y1~X1f, data=myd)
anova(regf)
Analysis of Variance Table
Response: Y1
Df Sum Sq Mean Sq F value Pr(>F)
X1f 4 742.16 185.54 38.02 4.424e-09 ***
Residuals 20 97.60 4.88
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
You can see changed X1f Df which is 4 instead of 1 in above case.
In contrast to ANOVA for qualitative variables, in context of quantitative variables where we do regression analysis - Analysis of Variance (ANOVA) consists of calculations that provide information about levels of variability within a regression model and form a basis for tests of significance.
Basically ANOVA tests the null hypothesis beta = 0 (with alternative hypothesis beta is not equal to 0). Here we do F test which ratio of variability explained by the model vs error (residual variance). Model variance comes from the amount explained by the line you fit while residual comes from the value that is not explained by the model. A significant F means that beta value is not equal to zero, means that there is significant relationship between two variables.
> anova(reg1)
Analysis of Variance Table
Response: Y
Df Sum Sq Mean Sq F value Pr(>F)
X 1 81.719 81.719 6.3331 0.0656 .
Residuals 4 51.614 12.904
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
Here we can see high correlation or R-squared but still not significant result. Sometime you may get a result where low correlation still significant correlation. The reason of non significant relation in this case is that we do not have enough data (n = 6, residual df = 4), so the F should be looked at F distribution with numerator 1 df vs 4 denomerator df. So this case we could not rule out slope is not equal to 0.
Let's see another example:
X = c(4,5,8,6,2, 5,6,4,2,3, 8,2,5,6,3, 8,9,3,5,10)
Y = c(3,6,9,8,6, 8,6,8,10,5, 3,3,2,4,3, 11,12,4,2,14)
reg3 <- lm(Y~X)
anova(reg3)
Analysis of Variance Table
Response: Y
Df Sum Sq Mean Sq F value Pr(>F)
X 1 69.009 69.009 7.414 0.01396 *
Residuals 18 167.541 9.308
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
R-square value for this new data:
summary(reg3)$r.squared [1] 0.2917296 cor(X,Y) [1] 0.54012 Although the correlation is lower than previous case we got a significant slope. More data increases df and provides enough information so that we can rule out null hypothesis that slope is not equal to zero. Lets take another example where there is negate correlation: X1 = c(4,5,8,6,12,15) Y1 = c(18,16,2,4,2, 8) # correlation cor(X1,Y1) -0.5266847 # r-square using regression reg2 <- lm(Y1~X1) summary(reg2)$r.squared
0.2773967
sqrt(summary(reg2)$r.squared) [1] 0.5266847 As values were squared square root will not provide information about positive or negative relationship here. But the magnitude is the same. Multiple regression case: Multiple linear regression attempts to model the relationship between two or more explanatory variables and a response variable by fitting a linear equation to observed data. The above discussion can be extended to multiple regression case. In this case we have multiple beta in the term: y = a + beta1X1 + beta2X2 + beta2X3 + ................+ betapXp + error Example: X1 = c(4,5,8,6,2, 5,6,4,2,3, 8,2,5,6,3, 8,9,3,5,10) X2 = c(14,15,8,16,2, 15,3,2,4,7, 9,12,5,6,3, 12,19,13,15,20) Y = c(3,6,9,8,6, 8,6,8,10,5, 3,3,2,4,3, 11,12,4,2,14) reg4 <- lm(Y~X1+X2) Let's see the coefficients of the model: reg4$coefficients
(Intercept) X1 X2
2.04055116 0.72169350 0.05566427
Thus your multiple linear regression model would be:
Y = 2.04055116 + 0.72169350 * X1 + 0.05566427* X2
Now lets test if the beta for X1 and X2 are greater than 0.
anova(reg4)
Analysis of Variance Table
Response: Y
Df Sum Sq Mean Sq F value Pr(>F)
X1 1 69.009 69.009 7.0655 0.01656 *
X2 1 1.504 1.504 0.1540 0.69965
Residuals 17 166.038 9.767
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
Here we say that the slope of X1 is greater than 0 while we could not rule that the slope of X2 being greater than 0.
Please note that slope is not correlation between X1 and Y or X2 and Y.
> cor(Y, X1)
[1] 0.54012
> cor(Y,X2)
[1] 0.3361571
In multiple variate situation (where the variable are greater than two Partial correlation comes into the play. Partial correlation is the correlation of two variables while controlling for a third or more other variables.
source("http://www.yilab.gatech.edu/pcor.R")
pcor.test(X1, Y,X2)
estimate p.value statistic n gn Method Use
1 0.4567979 0.03424027 2.117231 20 1 Pearson Var-Cov matrix
pcor.test(X2, Y,X1)
estimate p.value statistic n gn Method Use
1 0.09473812 0.6947774 0.3923801 20 1 Pearson Var-Cov matrix
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Analysis of variance (ANOVA) and regression are actually very similar (some would say they are the same thing).
In Analysis of variance, typically you have some categories (groups) and a quantitative response variable. You calculate the amount of overall error, the amount of error within a group and the amount of error between groups.
In regression, you don't necessarily have groups anymore, but you can still partition the amount of error into an overall error, the amount of error explained by your regression model and error unexplained by your regression model. Regression models are often displayed using ANOVA tables and it's an easy way of seeing how much variation is explained by your model.
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http://mathhelpforum.com/number-theory/96226-help-preparing-final-exam-print.html
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# Help Preparing for Final Exam
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• Jul 27th 2009, 11:06 AM
diddledabble
Help Preparing for Final Exam
I am trying to prepare for my final exam in NT. Any help would be appreciated. These questions are just for study purposes, I messed them up on my homework, etc.
Reduced Residue System Proof
Show that if a=b(mod n) then (a,n)= (b,n)
• Jul 27th 2009, 03:54 PM
Gamma
Quote:
Originally Posted by diddledabble
I am trying to prepare for my final exam in NT. Any help would be appreciated. These questions are just for study purposes, I messed them up on my homework, etc.
Reduced Residue System Proof
Show that if a=b(mod n) then (a,n)= (b,n)
$a \equiv b$ (mod n) $\Leftrightarrow n|(b-a) \Rightarrow nk=b-a$ for some integer k
Now we show the set of divisors of a and n are the same as the set of divisors of b and n.
Let d divide a and n.
$nk=b-a \Rightarrow b=nk+a$ then d divides the RHS so it divides b as well.
Let d divide b and n.
$nk=b-a \Rightarrow b-nk=a$ then d divides the LHS so it divides a as well.
Thus the set of divisors is the same, so their greatest element is the same. so (a,n)=(b,n)
• Aug 3rd 2009, 10:13 PM
streethot
First of all, assuming that $a\equiv b \ (mod \ m)$ we have that if $d|m$ and $d|a$ then $d|b$.
Proof:
$a-b=m.k$
$m=d.u$ and $a=d.s$
then
$b=d(s-u)$
Now, let $d=(a,m)$ and $e=(b,m)$. Then $d|m$, $d|a$ so $d|b$. Hence $d|e$.
Similarly, $e|m$, $e|b$ so $e|a$. Hence $e|d$. Therefore $d=e$
• Aug 4th 2009, 11:55 AM
diddledabble
Another Proof
Show that if 2n+1 is prime, then n must be a power of 2.
• Aug 4th 2009, 12:01 PM
Gamma
Not true
Quote:
Originally Posted by diddledabble
Show that if 2n+1 is prime, then n must be a power of 2.
$2\cdot 3 + 1=7$ is prime and 3 is not a power of 2.
• Aug 4th 2009, 12:08 PM
Gamma
Maybe what you meant was $2^n+1$ being prime implies $n=2^i$ for $i\in \{0,1,2,...\}$. If so, I would check out this:Fermat number - Wikipedia, the free encyclopedia
For completeness, it should state the n could also be 0.
• Aug 4th 2009, 12:09 PM
diddledabble
Quote:
Originally Posted by Gamma
$2\cdot 3 + 1=7$ is prime and 3 is not a power of 2.
Maybe I messed it up. It is supposed to be proveable. I thought of the counterwxample issue too. Maybe it should be $2^n+1$
or $2^{n+1}$
• Aug 4th 2009, 12:12 PM
Gamma
Quote:
Originally Posted by diddledabble
Maybe I messed it up. It is supposed to be proveable. I thought of the counterwxample issue too. Maybe it should be $2^n+1$
or $2^{n+1}$
You can't prove something is true if there is a counter-example... that is the beauty of math.
$2|2^{n+1}$ so it can never be prime if n is a natural number (not including 0), so that would be a pretty dull question. Probably it is what I suggested above.
• Aug 4th 2009, 12:13 PM
streethot
Gamma,
Show that IF 2n+1 is prime, then n must be a power of 2.
• Aug 4th 2009, 12:16 PM
diddledabble
Streethot, Everytime I read it I think of a different way to go with it. I think you have it though. 2^n+1 must be a prime to start with.
• Aug 4th 2009, 12:17 PM
Gamma
Quote:
Originally Posted by streethot
Gamma,
Show that IF 2n+1 is prime, then n must be a power of 2.
Yes, if $7=2\cdot 3 + 1$ is prime... which it is for n=3, then 3 should be a power of 2. It is not, therefore this statement is not even close to being true.
need another let n=5
or n=11?
need any more?
• Aug 4th 2009, 12:23 PM
diddledabble
But if it should have been $2^n+1$ let n=2 that is not a square. I just don;t get this one and fermat seems way to tough to be on the exam.
• Aug 4th 2009, 12:30 PM
streethot
Sorry, i thought the question was about $2^{m}+1$ with $m=2^n \ \ n\in\mathbb{N}$
• Aug 4th 2009, 12:33 PM
Gamma
The statement should be
IF $2^n+1$ is prime, then n is a power of 2 or n=0.
the proof is given here Fermat number - Wikipedia, the free encyclopedia
There is nothing complicated about the proof supplied in the link. It is a proven fact, this has to be what the teacher was going for, the other possibilities are either not true or would never be asked on an exam by someone with a PhD in math.
I am not following what your problem is with this, it is a very straightforward if then statement. The proof goes by contradiction in supposing that n is not a power of two, then it has an odd prime factor. Then you show how you factor $2^n+1$ which makes it NOT prime, a contradiction.
• Aug 4th 2009, 12:35 PM
Gamma
Quote:
Originally Posted by streethot
Sorry, i thought the question was about $2^{m}+1$ with $m=2^n \ \ n\in\mathbb{N}$
It is, that is what it means to be a power of 2.
Show 40 post(s) from this thread on one page
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http://crypto.stackexchange.com/questions/2249/how-does-one-attack-a-two-time-pad-i-e-one-time-pad-with-key-reuse
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# How does one attack a two-time pad (i.e. one time pad with key reuse)?
My question might appear the same as the question Taking advantage of one-time pad key reuse?, but actually I did read all the answers and none of them helped me with the details I need.
I am new to cryptography and my problem is with two time pad attacks on OTP. The problem I had in my course was that I have 10 ciphertexts encrypted with the same key $K$. I am then given another ciphertext that I should decrypt.
I know that XOR-ing two ciphers gives me the XOR of their original messages.
My question is what is the correct thing to do after that?
I tried to take 3 ciphertexts $C_1, C_2$ and $C_3$.
Then get $S_1 = C_1 \oplus C_2 \oplus$' ', also get $S_2 = C_1 \oplus C_3 \oplus$ ' '.
After that I compared all corresponding characters in $S_1$ and $S_2$, and if $S_1[i] = S_2[i]$ then I calculate $S_1[i] \oplus C_2[i]$ to get $K[i]$.
I tried this on paper before coding and it worked, but I might be missing something.
Is this the right approach? Why does it work?
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If string1[i] == string2[i], that only means that C2[i] == C3[i] (and thus M2[i] == M3[i]). You can check that fact without doing any of those XOR operations. And XORing string1 by C2 gives you back C1 XOR "space", which, at a glance, doesn't seem to be related to key[i]. I haven't looked at that EC assignment for the class in any detail yet, but I think you're supposed to use the fact that XORing by "space" only changes the case of the original character. You might use that fact to analyze the XOR or two plaintext messages, which you obtain by XORing their two respective ciphertexts. – B-Con Apr 1 '12 at 1:35
Yes, your totally right. I was mistaken with that part, but it is my very first trial in cryptography. I got it now – Samer Meggaly Apr 1 '12 at 20:21
Does "the class" include a disclaimer that the method needs to have $m_1 \neq m_2$ in order for the method to work? – Dilip Sarwate Jun 16 '12 at 11:35
@DilipSarwate: If $m_1=m_2$ then the key has still only been used once. Therefore it is implicitly clear that $m_1\neq m_2$ – Maeher Jun 16 '12 at 11:56
Well, the classical answer to "what is the correct thing to do after you have the XOR of the two original messages" is crib-dragging.
That is, you take a guess of a common phrase that may appear in one of the plaintexts (the classical example against ASCII english is the 5 letter " the "), and exclusive-or that against the XOR of the two original messages in various locations. If one of the plaintexts had the text of the crib (" the " in our example), then the result of the exclusive-or is what the other plaintext had in that position; if neither plaintext had that, it's likely that the result of the exclusive-or is just gibberish. And, once you have a plausible short section, you can extend it (for example, if you know that one of the plaintexts is " na**", you can go through the dictionary of all words that start with "na", use those as cribs, and see which makes the other plaintext make sense).
In addition, you can often deduce things directly from the bit pattern. For example, if the messages are in ASCII, then one thing to note that bit 6 of letters is set, but bit 6 of spaces, numbers and (most) punctuation is clear; because spaces are far more common than numbers and punctuation, then that will give you a good guess of where spaces occur in the texts (albeit without telling you which message a specific space appears in).
Now, if you have 11 messages all encrypted with the same pad (an "11-time pad"), things get even easier. Obviously, you can grab a crib across one message, and check it against the other 10; if it makes all 10 make sense, then it is almost certainly accurate. Even better, by using the observation that you can distinguish spaces from letters (again, by comparing bit 6), you can find where all the spaces appear in the messages; these all act like 1 character cribs, probably revealing virtually all the text of all the messages.
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Thanks, a lot i solved the problem. I started with ' the ' as you said and got 'robab' which i guessed would be 'probably'. I kept doing this with some guesses until i solved the whole message. Thanks again. – Samer Meggaly Apr 1 '12 at 20:23
Furthermore, consider contents of more common files - sometimes a bunch of binary files are XORd with the same OTP. Some header patterns make determining the key super easy if you know the type, for example some image type has a long string of null bytes. – deed02392 Mar 13 at 8:22
In general, knowledge of $m_1 \oplus m_2$ is not enough to uniquely determine $m_1$ and $m_2$, even if both are known to be, say, English text. For a simple example, $$\text{"one one"} \oplus \text{"two two"} = \text{"one two"} \oplus \text{"two one"}.$$
However, in practice it may be possible to obtain fairly good guesses for $m_1$ and $m_2$; the typical methods are similar to those used for breaking classical ciphers, and rely on the fact that there's a lot of redundancy in English text (and in many other types of data).
For example, one might start by guessing that at least one of the messages is likely to contain the word "the", probably surrounded by spaces. So one can take the five-character string " the ", XOR it with every five-character substring of $m_1 \oplus m_2$ and look for results that look like English (either by eye or by computer using statistical analysis).
Now, let's say that one of the five-character substrings thus obtained is, say, "messa". Now we (or a computer) could guess that the next two characters are likely to be "ge" (or perhaps "gi"). We can now XOR that with the next two characters of $m_1 \oplus m_2$ and see if the result fits naturally after " the "; if the result is, say, "la", we might tentatively assume our guess to have been right; if it's "q%", we probably guessed wrong. We can proceed in this manner to confirm and extend our guess further, and perhaps eventually to connect separate guessed fragments together until we have a reasonable guess of all, or at least most, of the content of the two messages.
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https://testbook.com/question-answer/in-a-row-of-students-a-is-8th-from-the-left-and-b--5ecd2fbdf60d5d024b9cd1c5
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# In a row of students, A is 8th from the left and B is 15th form the right. If they interchange their positions. A becomes 42th form the left. How many students are in the row?
Free Practice With Testbook Mock Tests
## Options:
1. 57
2. 55
3. 58
4. 56
### Correct Answer: Option 4 (Solution Below)
This question was previously asked in
LMRC Assistant Manager Electrical : 2019 Paper
LMRC Assistant Manager Electrical : 2018 Paper
## Solution:
Position of A from the left end = 8th
Position of B from the right end = 15th
After interchanging positions, the new position of A = 42nd
Total number of students in the row = (42 + 15) – 1
= 57 – 1
= 56
Hence, ‘56’ is the correct answer.
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https://physics.stackexchange.com/questions/222400/why-shouldnt-we-shine-laser-light-back-into-the-laser/222427
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# Why shouldn't we shine laser light back into the laser?
After every laser there is an optical isolator that ensures the laser light cannot re-enter the laser, if reflected and sent back.
What would actually happen if this were to happen? Would the laser break because of too much power?
• You can get further amplification, intensity-driven focusing effects, and bad things happen to the gain medium. Blowing up your expensive YAG crystal is a bummer... – Jon Custer Dec 5 '15 at 17:13
• would it blow up because too much power is delivered to it? – SuperCiocia Dec 5 '15 at 17:13
• An amplifier is designed for a certain input power. If the back reflection exceeds that level, than yes, it becomes too powerful for the gain medium. – Jon Custer Dec 5 '15 at 19:47
Its not true that feedback is detrimental to all laser systems. In fact, some laser systems rely on it heavily for frequency control. Specifically, diode laser systems in the Littrow Configuration use feedback from a diffraction grating in order to stimulate emission in the laser cavity at the wavelength specific to the first order of diffraction. Tuning the angle of the grating with a piezo electric device allows for precise frequency control of the laser. Other diode lasers, such as AR coated diode lasers rely on optical feedback in order to have enough light in the cavity to lase.
With that being said, optical isolators are still a good idea after the laser head output because back reflections from the optics downstream can cause optical feedback that cause the laser to lase in a mode that you don't want. This can produce laser frequency noise and mode hops which will ruin the operation of the laser, but won't necessarily cause physical damage. However, some diode chips have a maximum power threshold, and too much feed back (perhaps direct feedback with a mirror and the laser at full current) can damage the chip.
If the beam is amplified which is the the beam that emerges a laser amplifier then it is intense enough to damage the optics inside the system. Isolators are usually used for amplifiers then.
But for an oscillator, usually it is not a big issue for short-time period. However since you are sending back the beam it acts like noise for the laser's active material, specially for pulsed lasers.
As in the other answers, the reasons for preventing feedback can be 1) to avoid spurious amplification and possible damage, and 2) to avoid intensity instabilities
The second point is especially important in applications where low intensity noise is required. Dynamically, having feedback means that your system is formed by two coupled cavities, one active, the other passive. In the differential equation for the electric field $\dot{E}(t)=$ (...), feedback can be model as a term $+E(t-\tau)$, where $\tau$ is the roundtrip of the external cavity (the one that gives feedback). This makes the field at $t$ dependent on the field at $t-\tau$, and the dimension of the system goes to infinite (the field at $t-\tau$ depends on the field at $t-2\tau$ and so on). This allows all kind of dynamical instabilities to happen, including hopping, chaos, and excitability. You can find more info looking for Lang Kobayashi (for semiconductor lasers I guess). While all these behaviors are very interesting for people in non linear dynamics, for engineers and most of the users it is often a phenomenology to avoid.
Since the laser beam is focused on the spot of generating unit...it will produce more heat and will cause the crystal to damage..
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http://farside.ph.utexas.edu/teaching/315/Waveshtml/node92.html
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Next: Wavefunction Collapse Up: Wave Mechanics Previous: Wave Packets
# Heisenberg's Uncertainty Principle
According to the analysis contained in the previous section, a particle wave packet that is initially localized in -space, with characteristic width , is also localized in -space, with characteristic width . However, as time progresses, the width of the wave packet in -space increases [see Equation (1133)], while that of the packet in -space stays the same [because is given by Equation (1123) at all times]. Hence, in general, we can say that
(1134)
Furthermore, we can interpret and as characterizing our uncertainty regarding the values of the particle's position and wavenumber, respectively.
A measurement of a particle's wavenumber, , is equivalent to a measurement of its momentum, , because . Hence, an uncertainty in of order translates to an uncertainty in of order . It follows, from the previous inequality, that
(1135)
This is the famous Heisenberg uncertainty principle, first proposed by Werner Heisenberg in 1927 (Dirac 1982). According to this principle, it is impossible to simultaneously measure the position and momentum of a particle (exactly). Indeed, a good knowledge of the particle's position implies a poor knowledge of its momentum, and vice versa. The uncertainty principle is a direct consequence of representing particles as waves.
It is apparent, from Equation (1133), that a particle wave packet of initial spatial extent spreads out in such a manner that its spatial extent becomes
(1136)
at large . It is readily demonstrated that this spreading of the wave packet is a consequence of the uncertainty principle. Indeed, because the initial uncertainty in the particle's position is , it follows that the uncertainty in its momentum is of order . This translates to an uncertainty in velocity of . Thus, if we imagine that part of the wave packet propagates at , and another part at , where is the mean propagation velocity, then it follows that the wave packet will spread out as time progresses. Indeed, at large , we expect the width of the wave packet to be
(1137)
which is identical to Equation (1136). Evidently, the spreading of a particle wave packet, as time progresses, should be interpreted as representing an increase in our uncertainty regarding the particle's position, rather than an increase in the spatial extent of the particle itself.
Next: Wavefunction Collapse Up: Wave Mechanics Previous: Wave Packets
Richard Fitzpatrick 2013-04-08
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https://rd.springer.com/chapter/10.1007/978-0-8176-8152-4_6
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# The Tent Method in Finite-Dimensional Spaces
Part of the Systems & Control: Foundations & Applications book series (SCFA)
## Abstract
The Tent Method is shown to be a general tool for solving a wide spectrum of extremal problems. First, we show its workability in finite-dimensional spaces. Then topology is applied for the justification of some results in variational calculus. A short historical remark on the Tent Method is made and the idea of the proof of the Maximum Principle is explained in detail, paying special attention to the necessary topological tools. The finite-dimensional version of the Tent Method allows one to establish the Maximum Principle and to obtain a generalization of the Kuhn–Tucker Theorem in Euclidean spaces.
## Keywords
Maximum Principle Extremal Problem Variational Calculus Conditional Extremum Tucker Theorem
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
## References
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16. Polyak, B.T. (1987), Introduction to Optimization, Optimization Software Publication Division, New York. Google Scholar
17. Pontryagin, L.S., Boltyansky, V.G., Gamkrelidze, R.V., & Mishenko, E.F. (1969), Mathematical Theory of Optimal Processes, Nauka, Moscow (in Russian). Google Scholar
18. Poznyak, A.S. (2008), Advanced Mathematical Tools for Automatic Control Engineers, Vol. 1: Deterministic Technique, Elsevier, Amsterdam. Google Scholar
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https://www.lessonplanet.com/teachers/fill-in-the-missing-numbers-5th-6th
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# Fill in the Missing Numbers
In this math learning exercise, students complete a 36 square math puzzle. Students examine the 6 numbers on a diagonal and figure out the pattern before filling out the grid.
Concepts
Resource Details
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https://proofwiki.org/wiki/Mathematician:Mathematicians/Sorted_By_Nation/Italy
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# Mathematician:Mathematicians/Sorted By Nation/Italy
For more comprehensive information on the lives and works of mathematicians through the ages, see the MacTutor History of Mathematics archive, created by John J. O'Connor and Edmund F. Robertson.
The army of those who have made at least one definite contribution to mathematics as we know it soon becomes a mob as we look back over history; 6,000 or 8,000 names press forward for some word from us to preserve them from oblivion, and once the bolder leaders have been recognised it becomes largely a matter of arbitrary, illogical legislation to judge who of the clamouring multitude shall be permitted to survive and who be condemned to be forgotten.'
-- Eric Temple Bell: Men of Mathematics, 1937, Victor Gollancz, London
## Italy
##### Gerard of Cremona (c. 1114 – 1187)
Italian scholar whose calling was to translate Arabic scientific and mathematical papers into Latin, many of which themselves were translations of works originally written in Greek.
Some sources credit him for the mistranslation that led to the word sine, but this may be more reliably attributed to Robert of Chester, who appears to be earlier.
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##### Leonardo Fibonacci (c. 1170 – c. 1250)
Italian mathematician.
One of the most important figures in the history of the development of mathematics.
Wrote the highly influential and important Liber Abaci in which he discussed the Hindu-Arabic number system and its practical applications.
Most famous for the Fibonacci numbers. The number sequence itself was known to Indian mathematicians as early as the 6th century, but it was Fibonacci's Liber Abaci which made them well-known throughout Europe.
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##### Campanus of Novara (c. 1220 – 1296)
Italian mathematician, astronomer, astrologer, and physician who is best known for his work on Euclid's The Elements.
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##### Antonio Maria del Fiore (15th century – 16th century)
Italian Renaissance mathematician, sometimes rendered as Antonio Fior.
A student of Scipione del Ferro, learned from him the formula for the resolution of the particular cubic equation $x^3 + px = q$, and boasted that he was the only one who could solve such equations.
Challenged Niccolò Fontana Tartaglia to a contest in 1535 to solve cubics, but was outclassed.
Some sources suggest that it was del Fiore who revealed to Gerolamo Cardano that the solution originated from del Ferro and not Tartaglia.
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##### Piero Della Francesca (1412 – 1492)
Italian painter and mathematician.
Recognized as one of the most important Renaissance painters, but was also a creditable mathematician.
His surviving mathematical works concern such subjects as: the abacus; the five Platonic solids, and perspective in painting.
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##### Luca Bartolomeo de Pacioli (1447 – 1517)
Italian mathematician and Franciscan friar who was a pioneer in the field of accounting.
Sometimes referred to as "The Father of Accounting and Bookkeeping".
The first person to publish a work on the double-entry system of book-keeping.
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##### Leonardo da Vinci (1452 – 1519)
Italian polymath whose areas of interest included invention, painting, sculpting, architecture, science, music, mathematics, engineering, literature, anatomy, geology, astronomy, botany, writing, history, and cartography.
Variously called the father of palaeontology, ichnology, and architecture.
Widely considered one of the greatest painters of all time.
Sometimes credited with the inventions of the parachute, helicopter and tank.
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##### Scipione del Ferro (1465 – 1525)
Italian mathematician.
First one to come up with a solution to the general cubic equation, which was later published by Cardano and is now known as Cardano's Formula.
Contributed towards the rationalization of fractions.
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##### Francesco Maurolico (1494 – 1575)
Mathematician and astronomer from Sicily, notable for being the first on record to use the Principle of Mathematical Induction.
Contributed to the fields of geometry, optics, conics, mechanics, music, and astronomy.
Edited the works of classical authors including Archimedes, Apollonius, Autolycus, Theodosius and Serenus.
Composed treatises of his own on mathematics and mathematical science.
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##### Niccolò Fontana Tartaglia (1499/1500 – 1557)
Italian mathematician, engineer and surveyor.
##### Gerolamo Cardano (1501 – 1576)
Italian mathematician, physician, inventor, astrologer and gambler.
##### Lodovico Ferrari (1522 – 1565)
Lodovico (or Ludovico) Ferrari was an Italian mathematician.
Student of Gerolamo Cardano.
First one to devise a solution to the general quartic equation, which was later published by Cardano and is now known as Ferrari's Method.
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##### Rafael Bombelli (1526 – 1572)
Italian mathematician whose influence may have been greater than is currently recognised.
##### Pietro Antonio Cataldi (1548 – 1626)
Italian mathematician and philanthropist who taught mathematics and astronomy.
Worked on the development of perfect numbers and continued fractions.
Attempted in vain (as so many before and since) to prove Euclid's fifth postulate.
Supposed to have discovered the $6$th and $7$th Mersenne primes $M_{17}$ and $M_{19}$ in $1588$.
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##### Galileo Galilei (1564 – 1642)
Italian mathematician and scientist usually known as just Galileo.
At the forefront of a revolution in the understanding of physics. One of the most influential thinkers in history.
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##### Bonaventura Cavalieri (1598 – 1647)
Italian mathematician who worked on optics and motion.
His approach to geometry was a precursor to integral calculus.
Introduced the logarithm to Italy.
A disciple of Galileo.
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##### Evangelista Torricelli (1608 – 1647)
Italian physicist and mathematician, best known for inventing the barometer.
Disciple of Galileo.
Gave his name to Torricelli's Law.
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##### Giovanni Domenico Cassini (1625 – 1712)
Italian/French mathematician, astronomer, engineer, and astrologer.
Most of his important discoveries were in the field of astronomy.
Also known as Giandomenico Cassini or Jean-Dominique Cassini.
Not to be confused with his son, also called Jean-Dominique Cassini.
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##### Pietro Mengoli (1626 – 1686)
Italian mathematician who spent most of his working life as a professor at the University of Bologna.
Also ordained into the Priesthood.
Occupies the philosophical transitional ground between the work of Bonaventura Cavalieri and that of Isaac Newton and Gottfried von Leibniz.
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##### Giovanni Ceva (1647 – 1734)
Italian mathematician best known for Ceva's Theorem, a result in geometry.
Also rediscovered and published Menelaus's Theorem.
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##### Luigi Guido Grandi (1671 – 1742)
Guido Grandi was an Italian mathematician, engineer, priest and philosopher, best known for his study of the rose curve.
Contributed to Note on the Treatise of Galileo Concerning Natural Motion in the first Florentine edition of Galileo Galilei's works.
Helped introduce Gottfried Leibniz's ideas on calculus to Italy.
Also known for Grandi's Series.
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##### Jacopo Francesco Riccati (1676 – 1754)
Count Jacopo Francesco Riccati was an aristocratic Italian mathematician and jurist from Venice.
Chiefly responsible for introducing Isaac Newton's ideas to Italy.
Best known for having founded the equation which bears his name.
Contributed towards Maria Gaëtana Agnesi's 1748 work Instituzioni analitiche ad uso della gioventù italiana.
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##### Maria Gaëtana Agnesi (1718 – 1799)
Italian mathematician, linguist and philosopher famed for writing the first book discussing both integral and differential calculus.
The curve in analytic geometry called the Witch of Agnesi is named for her.
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##### Joseph Louis Lagrange (1736 – 1813)
Italian-born French mathematician who made big advances in the fields of the calculus of variations and analytical mechanics.
Contributed to number theory and algebra.
Extended a lot of the fields established by Euler, and in turn laid down the groundwork for later explorations by Gauss and Abel.
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##### Lorenzo Mascheroni (1750 – 1800)
Professor of mathematics at Pavia.
Wrote Geometria del Compasso, published in 1797, in which he showed that any geometrical construction that can be made with compasses and straightedge can also be achieved by using only compasses. This had, however, already been demonstrated by Georg Mohr in 1672.
Published in his 1790 work Adnotationes ad Calculum Integrale Euleri a calculation to 32 places of the value of what is now known as the Euler-Mascheroni Constant. However, only the first 19 places were accurate. The rest were corrected in 1809 by Johann von Soldner.
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##### Paolo Ruffini (1765 – 1822)
Italian mathematician and philosopher.
Most famous for his incomplete proof of what is now known as the Abel-Ruffini Theorem proving the insolubility of the general quintic with radicals.
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##### Giuliano Frullani (1795 – 1834)
Italian mathematician interested in definite integrals and infinite series.
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##### Angelo Genocchi (1817 – 1889)
Italian mathematician who specialized in number theory.
Worked with Giuseppe Peano.
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##### Francesco Faà di Bruno (1825 – 1888)
Italian mathematician and priest, most famous (in mathematics) for Faà di Bruno's Formula on derivatives of composite functions.
Also notable for his beatification on 25th September 1988 by Pope John Paul II.
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##### Giuseppe Battaglini (1826 – 1894)
Italian mathematician best known for being the founder of Giornale di Matematiche, later known as Giornale di Matematiche di Battaglini.
Also did considerable work in the field of non-Euclidean geometry.
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##### Felice Casorati (1835 – 1890)
Italian mathematician best known for the Casorati-Weierstrass Theorem in complex analysis.
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##### Ulisse Dini (1845 – 1918)
Italian mathematician and politician, best known for his contributions to real analysis.
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##### Vilfredo Federico Damaso Pareto (1848 – 1923)
Italian engineer, sociologist, economist, political scientist, and philosopher.
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##### B. Nicolò I. Paganini (c. 1850 – ?)
Italian amateur mathematician known now only for his discovery of the $2$nd amicable pair $1184$ and $1210$.
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##### Giovanni Frattini (1852 – 1927)
Italian mathematician noted for his contributions to group theory.
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##### Alfredo Capelli (1855 – 1910)
Italian mathematician best known for Capelli's Identity.
Also pioneered the notation $x^{\overline k}$ and $x^{\underline k}$ for rising factorial and falling factorial respectively.
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##### Giacinto Morera (1856 – 1909)
Italian mathematician and engineer best remembered for his work in complex analysis and the theory of linear elasticity.
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##### Giuseppe Peano (1858 – 1932)
Italian mathematician who contributed significantly to the founding of the fields of mathematical logic and set theory.
Invented many of the symbols used today in these fields.
Worked on the axiomatization of mathematics, and contributed greatly towards the method of mathematical induction.
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##### Ernesto Cesàro (1859 – 1906)
Italian mathematician who worked mainly in the fields of differential geometry and number theory.
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##### Cesare Burali-Forti (1861 – 1931)
Italian mathematician best known for discovering what is now known as the Burali-Forti Paradox.
Disbelieved in the Theory of Relativity, and even went so far as to write a book attempting to refute it.
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##### Gino Benedetto Loria (1862 – 1954)
Italian mathematician and historian of mathematics.
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##### Gino Fano (1871 – 1952)
Italian mathematician best known as the founder of the finite geometry.
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##### Beppo Levi (1875 – 1961)
Italian mathematician best known for his work on algebraic curves and Lebesgue integration.
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##### Giuseppe Vitali (1875 – 1932)
Italian mathematician who worked in several branches of analysis.
Best known for the Vitali set: a subset of the real numbers which is not Lebesgue measurable.
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##### Francesco Paolo Cantelli (1875 – 1966)
Italian mathematician best known for his work in probability theory, and for the Borel-Cantelli Lemma.
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##### Guido Fubini (1879 – 1943)
Italian mathematician best known for Fubini's Theorem and the Fubini-Study metric.
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##### Ruggiero Torelli (1884 – 1915)
Italian mathematician whose work was mainly in algebraic geometry and the non-rational functions of the points of a Riemann surface.
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##### Leonida Tonelli (1885 – 1946)
Italian mathematician, noted for creating Tonelli's Theorem.
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##### Enrico Bombieri (b. 1940 )
Italian mathematician known for his work in analytic number theory, algebraic geometry, univalent functions, theory of several complex variables, partial differential equations of minimal surfaces, and the theory of finite groups
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##### Mariano Giaquinta (b. 1947 )
Italian mathematician mainly known for his contributions to the fields of calculus of variations and regularity theory of partial differential equation.
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https://crypto.stackexchange.com/questions/20268/secure-symmetric-encryption-algorithm-for-any-size-base62-data/24818
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# Secure symmetric encryption algorithm for any-size base62 data
I am searching for a secure algorithm to encrypt base62 (or any other base) data for ids in urls.
It should feature:
• No blocksize etc, limiting the length of the message to a factor of n
• If you have the decryted and the encrypted message you should not be able to guess the key
• An avalanche effect
• Any size of charset, not only 256 like in AES, DES etc.
• High performance on modern CPUs
This is not required:
• Streaming, it is only for small data
Is this possible?
• I have a few ciphers like that, BUT they each have a very specific block size (35, 40, 42, 48 bits) and have i/o in 5 or 6-bit character sets, their purpose to be a secure permutation for URL generation from a counter – Richie Frame Nov 16 '14 at 11:23
• Pastebin uses 8 base62 characters for his IDs. Does Pastebin uses random IDs which are also stored in the database? – user18296 Nov 16 '14 at 11:32
• are you looking for format preserving encryption ? – sashank Nov 16 '14 at 14:52
• they probably do not store the counter used to generate it, it is not a necessity. i do not know the precise method that pastebin and imgur use, or if it is cryptographically secure – Richie Frame Nov 17 '14 at 2:49
• So, important question: is it required that the result remains the same size or is the ciphertext allowed to be larger than the encoded URL? – Maarten Bodewes Jun 6 '15 at 14:38
If you define your encryption to be $C=E_{62}(E_k(D_{62}(P)))$ and your decryption to be $P=E_{62}(D_k(D_{62}({C})))$ where $P$ is your encoded URL then you've brought back your problem to finding an encryption function for $l$ bits, where $l$ is the size of $D_{62}(P)$. After that you can "just" look for a Format Preserving Encryption primitive for those $l$ bits. If the encrypted URL is allowed to be larger than the unencrypted URL then you could use CTR mode with a nonce of 8 random bytes.
• An 8-byte random nonce has a birthday bound of only $2^{32}$, which doesn't offer a lot of margin unless encrypting very few items. I would be more comfortable with either a counter value or a 128-bit nonce. – otus Jul 7 '15 at 11:37
• Also, would you mind defining your operators? – otus Jul 7 '15 at 11:38
• $E_{62}$ is encoding of data, $D_{62}$ is decoding, while $E_k$ is the encryption transformation using the FPE or the CTR cipher. I thought these functions would be clear. The 8 byte IV is the absolute minimum which indeed carries a risk. This risk could be worth it if the amount of data is small ("it is only for small data" can either be read as small packets or a minimal amount of data). Of course if there are many packets then the IV/nonce should be larger as the chance of a collision of the counter rises with the amount of blocks due to the birthday "paradox". Thanks for the warning @otus. – Maarten Bodewes Jul 7 '15 at 17:55
If I'm understanding things right you want something that can encrypt data at abritrary size with high speed. You have several options here:
• CTR mode. This turns any block cipher into a stream cipher allowing you to encrypt arbitrary amounts of data at high speeds. (cipher would be AES-128)
• a dedicated streamcipher like Salsa20 or ChaCha. They are high-speed and can encrypt arbitrary amounts of data
The only thing you'd need is an unique IV
• CTR mode with truncated output has collisions – Richie Frame Jun 6 '15 at 3:38
• @RichieFrame, Indeed if you truncate the output of the encryption of the counter it has indeed collisions after $2^{64}$ blocks and without the truncations collisions will occur after $2^{128}$ blocks. But the OP stated that's only for small amounts of data and hence collisions shouldn't be a problem if CTR is used as a proper stream cipher. – SEJPM Jun 6 '15 at 10:15
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https://wattsupwiththat.com/2018/04/24/did-official-climatology-know-its-predictions-were-nonsense/
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# Did official climatology know its predictions were nonsense?
Guest opinion by Christopher Monckton of Brenchley
In this series, we have demonstrated beyond reasonable doubt, that after correction of the giant error of physics by which official climatology defined feedbacks in such a way as to exclude or misallocate the large feedback response to emission temperature, global warming in response to doubled CO2 will not be 2-4.5 K with a mid-range estimate of 3.3 K, as the modelers would have us believe, but not much more than 1.2 K.
The question arises: did They know of Their grave error?
They were and are utterly unable to provide a convincing answer to the following question:
How do the inanimate water vapor, albedo and other feedback processes in the climate know that they must respond little, if at all, to the 255 K emission temperature, but that they must suddenly respond with as much as 22-24 K of feedback-driven warming triggered by the extra 9-11 K of temperature directly forced by the presence of the non-condensing greenhouse gases?
Will official climatology now climb down and fess up? Will the IPCC, the UNFCCC, and the alphabet-soup of national, international and global profiteers of doom be shut up, shut out and shut down? Will the Paris climate treaty be torn up? Will the war on coal cease? Will the countryside no longer be trashed by bird-blending, bat-blatting windmills?
Windmills, for heaven’s sake – 14th-century technology to solve a 21st-century non-problem. Will the subsidies stop and power prices fall by two-thirds, as they should?
The answer, of course, is No. For They are in denial. They are the denialists now.
University of Untruthfulness
Some months ago, an outline of our result was sent – behind our backs – to a university long known for its unswerving adherence to the totalitarian Party Line on the climate question, and, indeed, on all questions. There is no Conservative Association on campus, not because there are no supporters of HM Government there, but because the “societies officer” at the students’ union has the right to decide what political societies may and may not be represented on campus, and he has deemed the nation’s governing party to be insufficiently totalitarian to provide a “safe space” for snowflake students. He has banned its supporters at the university from forming any association, holding meetings on or off campus or distributing party materials.
Freedom of speech, thought and political association, once guaranteed by Magna Carta, have been silently, stealthily taken away. How the snowflakes will blub when they learn of our result.
The vice-chancellor, on hearing of our result and on realizing that, when it is eventually published, it will cost the university hundreds of millions a year, summoned a meeting of the entire environmental-sciences faculty and yelled at them: “Monckton’s paper is a catastrophe for us.” He hollered at them that they should drop everything else they were doing and work full-time on trying to refute our result. Some weeks later, postgraduate students went on strike because the faculty were so busy trying to please the vice-chancellor by refuting the irrefutable that they were no longer providing the personal supervision that the postgrads were contractually entitled to expect.
One of those who heard the vice-chancellor feared that the university would expose itself to fraud charges if it failed to admit that the Party Line had been wrong all along and instead went on applying for hundreds of millions of dollars a year in taxpayer funding for research on global warming that its senior members knew was not and is not going to happen at anything like the predicted rate. He broke ranks. There is goodness even in the grim, concrete camps of the Forces of Darkness. That is how we learned of the vice-chancellor’s meeting.
We were also told that one of the faculty, furious that we had rather easily and rather completely demolished the nonsense he and his colleagues had been peddling for decades, decided to respond to our scientific argument in the fashion of totalitarian extremists everywhere. He stood outside his lecture-hall and handed out copies of a personal attack on me that had been published some years previously in a totalitarian daily propaganda-sheet in London. There was not a single scientific statement in the entire article. It was pure hate speech of the sort we are all used to. Its educational value to students of environmental sciences was nil.
On obtaining irrefutable evidence of the vice-chancellor’s remarks to the faculty, and of the lecturer’s consequent circulation of childish libels against me as though they constituted scientific evidence of anything, an overseas journalist telephoned the university’s head of publicity and asked for a comment. The head of publicity unwisely denied that the meeting of which we had received a direct report had taken place, and also denied that any lecturer had handed out propaganda to my detriment to his students.
However, the university’s website is notoriously insecure. We were able to download an image of the hate-speech document in question. We got it from the lecturer’s own area of the website, where he had prominently (if unwisely) displayed it. The university’s head of publicity had lied, and we were and are in a position to prove it, definitively.
The university now finds itself in a difficult position entirely of its own making. It now knows with a chilling certainty that manmade global warming will be small, slow, harmless and beneficial. Yet despite that knowledge – knowledge that we can prove the entire faculty of environmental sciences now possesses – it is continuing to preach the Party Line to its students.
And that constitutes fraud. It is fraud against the Government, which heavily subsidizes the university and expects it to produce sound science, not totalitarian propaganda. It is fraud against the students, who pay good money to be taught what is true and are now being lied to. It is fraud against every taxpayer and user of gasoline or electricity, for all of us pay through the nose to subsidize the deeply unpleasant coalition of canting vested interests profiteering from the climate scam at great and damaging expense to the general public.
It is, as Professor Nils-Axel Mörner has rightly said, the greatest lie ever told. When I recover from a recent illness, reports of the university’s frauds will be sent to the public authorities, which will at first try to get away with doing what they do best: nothing. However, Britain is still in one or two respects a free country. It is open to us, if we wish, to institute a private prosecution. In due course, not only the university but any public authority that should have acted upon being given evidence of its fraud but did not act will face prosecution.
How long has official climatology known of its grave error? In truth, the vast majority of the pietistic preachers of doom and gloom have never had the slightest idea what they were talking about. They can – and, in due course, will – plead ignorance. And they will find to their horror, as the cell door slams behind them, that, in English criminal law, to intend to profit by proclaiming that something false is true when one does not know whether it is true or false is no less a deception than to proclaim that something one knows to be false is true.
But the university, which, being unspeakable, shall be nameless (though you can have fun trying to work out which it is from the not particularly informative illustrations) can no longer plead ignorance. It knows the truth, and it knows we know it knows the truth. I wrote to the vice-chancellor, on hearing of the meeting at which he had summoned the entire faculty and had yelled at them, and suggested that he should let me present our scientific results at a faculty lecture. He was unwise enough not to reply.
The extraordinary reactions of the vice-chancellor and of the lecturer are evidence in themselves that those driving the global warming scam, as opposed to the army of useful idiots who unthinkingly and rebarbatively regurgitate the Party pabulum, have known for some time that the very high climate sensitivities they have been luridly predicting cannot and will not occur, and that the true rate of manmade warming will be far too small to matter.
There is plenty more evidence that the Forces of Darkness knew They were making stuff up. I shall now rather breathlessly summarize this series. It will become apparent to anyone with an open mind that the debate is now indeed over, and that the result is not at all what the usual suspects had expected, and that our result is so obvious that They – or the brighter ones among Them, at any rate – must have known the truth.
IPCC’s official definition of a “climate feedback” is as follows (with my italics):
“Climate feedback An interaction in which a perturbation in one climate quantity causes a change in a second, and the change in the second quantity ultimately leads to an additional change in the first. A negative feedback is one in which the initial perturbation is weakened by the changes it causes; a positive feedback is one in which the initial perturbation is enhanced. In this Assessment Report, a somewhat narrower definition is often used in which the climate quantity that is perturbed is the global mean surface temperature, which in turn causes changes in the global radiation budget. In either case, the initial perturbation can either be externally forced or arise as part of internal variability.”
This definition very deliberately excludes the feedback response to the input signal. I say “very deliberately” because the word “perturbation” or its variants appears five times. Whoever drafted it knew perfectly well that the large feedback response to the large emission temperature must be taken no less into account than the small feedback response to any small perturbation of it driven by a radiative forcing. But IPCC’s author was most energetic in trying to mislead readers into overlooking the feedback response to emission temperature and concentrating only on the perturbation.
The corrected definition is as follows:
“Climate feedback, external or inherent, modifies an output signal by returning part of it to the input. Negative feedback attenuates the output; positive feedback amplifies it. A temperature feedback, in W m–2 K–1 of the output (equilibrium temperature), induces a feedback response in Kelvin that modifies the output even where the input (emission temperature) was unamplified.”
IPCC’s definition is 114 words: mine is half that length. Unlike IPCC, I am not ducking and diving and circumnavigating the truth without ever landing upon it. The standard, textbook feedback loop diagram makes it quite clear that even an unamplified input signal, which in the absence of amplification is also the output signal before accounting for feedback, must induce a feedback response if a nonzero feedback process is present:
The feedback loop diagram for the standard zero-dimensional-model equation
Teq = Tref μ / (1 – μβ)
In this standard feedback loop (see Bode 1945, ch. 3), the reference system that will operate whether or not a feedback is present comprises the input signal Tref and the μ gain block. The β feedback loop returns some fraction of the output signal from node P2 to the input node P1.
The mathematics of feedback applies to every dynamical system (i.e., a system that changes its state over time) in which feedback processes are present. It is not optional. Therefore, it is blindingly obvious – once it is pointed out, at any rate – that IPCC’s official definition of a “climate feedback” is plumb wrong, and that even with a unit μ direct-gain or open-loop-gain factor, indicating no amplification at all from any forcing, any nonzero value of the feedback fraction β must induce a feedback response that modifies the output signal.
A remarkable benefit of using the correct definition of a “temperature feedback” is that it becomes possible, for the first time, to solve the biggest problem in climate-sensitivity studies, which is to discover how big (or, as we shall see, how small) the feedback fraction is.
This matters, because at present the official feedback fraction is little better than guesswork, and IPCC et hoc genus omne use feedbacks as the excuse to triple – and, in several extreme papers, to multiply up to tenfold – the small direct warming from doubled CO2. Without big feedbacks, there is no big warming.
We know that at today’s insolation and albedo the emission temperature that would obtain at the Earth’s surface in the absence of any forcing and before accounting for feedback is about 255 K. Actually it is probably 10-20 K higher than that, but that is a story for another time.
We know that the radiative forcing from the presence of the naturally-occurring CO2 in the air in 1850 was about 30 Watts per square meter, which, when multiplied by 0.3 to allow for the Planck parameter at that time, was 9 K of CO2-driven warming.
We know that IPCC currently imagines that the CO2-driven warming should be increased by 35% to allow for all other anthropogenic forcings, so that the directly-forced warming from all natural sources was about 12 K.
We know that the temperature in 1850, at the beginning of the global temperature record and before any appreciable anthropogenic influence, was about 287 K. And we know that that 287 K was an equilibrium, for we had not yet noticeably perturbed the climate.
Armed with just these three generally accepted round numbers – emission temperature 255 K, directly-forced natural greenhouse-gas warming 12 K and equilibrium temperature 287 K in 1850 – we can obtain the feedback fraction without further ado. It is 1 – (255 + 12) / 287, or 0.07. James Bond would be delighted.
We know that the CMIP5 models predict 1.1 K directly-forced warming from doubled CO2, and that their mid-range estimate of equilibrium sensitivity after accounting for feedback is 3.3 K. So official climatology imagines that the feedback fraction is 1 – 1.1 / 3.3, or 0.67. But our feedback fraction is a proven result. Official climatology’s feedback fraction is ten times too big. Corrected Charney sensitivity, which is equilibrium sensitivity to doubled CO2 with all else held fixed, is then 1.1 / (1 – 0.07), which is not 3.3 K. It is 1.2 K. End of climate problem.
So, how much global warming do we say should have happened since 1850? IPCC says net anthropogenic forcing in the industrial era to 2011 was 2.3 Watts per square meter (IPCC 2013, fig. SMP.5, lower panel). Divide that by 3.2, today’s value of the Planck parameter, to get the equivalent directly-forced warming before accounting for feedback. It is 0.7 K.
So, using our feedback fraction 0.07, equilibrium warming since 1850 should have been 0.7 / (1 – 0.07), which is 0.75 K. And how much warming was measured, according to the HadCRUT4 dataset for 1850-2011? It was (wait for it) 0.75 K. Our result matches observed reality. Official climatology’s result, not so much: 0.7 / (1 – 0.67) = 2.1 K, almost three times observation.
But wait, say the naysayers. What about the Earth’s radiative imbalance of 0.6 Watts per square meter? This implies that anthropogenic warming has radiated 2.3 – 0.6 = 1.7 W m–2 to space. Accordingly, equilibrium warming attributable to the period from 1850-2011 may eventually prove to be 0.75 K x 2.3 / 1.7 = 1.0 K.
Right. Even after allowing for the energy imbalance, official climatology’s grossly excessive feedback fraction still gives a mid-range prediction more than twice the 1 K that may eventually be observed, whereas our result remains close to reality, Indeed, if just a quarter of the 1 K equilibrium warming from 1850- 2011 was natural, as it may well have been, for the official “consensus” proposition says no more than that recent warming was mostly manmade (and only 0.3% of published papers say even that much: Legates et al., 2013), our result remains bang on target.
But wait, say the naysayers. What about nonlinearity in feedbacks? The atmospheric burden of water vapor increases exponentially at around 7% per Kelvin of warming. Yes, it does, but the radiative feedback response to that additional water vapor is logarithmic, just like the direct forcing from CO2, so the overall effect of the water vapor feedback is linear. Other feedbacks are not as nonlinear as column water vapor, and are too small to make much difference.
Besides, the models assume only 1-2% growth in column water vapor per Kelvin, because the evaporative cooling from 7%-per-Kelvin exponential growth in water vapor would reduce Charney sensitivity to below 1 K per CO2 doubling (Kininmonth 2010). The formidable Professor Lindzen has made the same point.
Nevertheless, let us assume, just for the sake of accommodating the New Denialists, that the linear growth in the feedback fraction would give a value double the 0.07 we have calculated. Then Charney sensitivity would rise from 1.1 / (1 – 0.07) = 1.2 K to 1.1 / (1 – 0.14) = 1.3 K. At triple the real value, Charney sensitivity would be 1.1 / (1 – 0.21) = 1.4 K.
So let us near-quadruple it to 1 – 0.75 / 1.00 = 0.25, the value that would obtain if one believed that the energy imbalance is as big as 0.6 W m–2 and if one believed that the net anthropogenic forcing (greatly diminished by the aerosol fudge-factor hastily introduced some years ago by IPCC when it realized that without the fudge-factor equilibrium sensitivity would necessarily be very low: you should just hear Dick Lindzen on that subject) is as little as 2.3 W m–2. Let’s pretend.
In that event, Charney sensitivity would still be less than 1.5 K and, therefore, below the lower bound of IPCC’s official 1.5-4.5 K range, and half a Kelvin below the CMIP3 and CMIP5 models’ 2 K minimum. To get to the models’ minimum, one would have to assume a feedback fraction almost seven times the 0.07 we have calculated.
Nonlinear? Schmoninear.
But, say the naysayers (now desperate), how do you know that the models don’t take the feedback response to emission temperature fully into account when deriving their value of the feedback fraction? It is questions like this that reveal that there are plenty of climate fanatics who know perfectly well that official climatology is fatally in error.
Look at it this way. The directly-forced warming from the presence of the naturally-occurring, non-condensing greenhouse gases is about 12 K. The difference between equilibrium temperature in 1850 and emission temperature is 32 K. So, using official climatology’s method, carefully omitting the feedback response to emission temperature, its feedback fraction is 1 – 12 / 32, or 0.63. Actually, the CMIP5 models, like the CMIP3 models, assume 0.67, and Lacis (2010) assumes 0.75. So we know They are getting it wrong, and we know where and why They are getting it wrong, even without reading Their cheesily dishonest definition of a “climate feedback”.
What is more, Lacis says the pre-industrial and current values of the feedback fraction are the same: 0.75. Not much nonlinearity there, then.
If official climatology were using our method, it would have had to include the emission temperature in the calculation, thus: 1 – (255 + 12) / 287 = 0.07, or something pretty close to that.
Now you know why that hapless, red-faced, sweating vice-chancellor yelled at his faculty that our result is “a catastrophe” for the profiteers of doom. So it is.
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Gus
April 24, 2018 1:22 pm
Your Highness, or however you are meant to be addressed in this strange British aristocratic system of yours, which we here in the US are bound (by law) to disrespect… I’d like to see your paper properly published. There are many journals, not necessarily American or British, that will accept the paper. Try Japanese or Chinese journals, for example, of physics journals, or geophysics journals.
There have been insightful papers published recently on related issues. For example, Lewis & Curry argue, based on the actual physical data, for much lower climate response values than the ones returned by CMIP5 models [1]. Christy et al., find that the warming trend is much lower than that simulated by CMIP5 models too [2], which suggests much lower sensitivity as well.
[1] https://doi.org/10.1175/JCLI-D-17-0667.1
[2] https://doi.org/10.1080/01431161.2018.1444293
Chimp
April 24, 2018 2:12 pm
IMO Chris has already been published in a Chinese journal, or his team has submitted its work to the premier scientific periodical there.
As for terms of spoken address in the UK peerage, it goes like this (for Baronesses, etc, Lady instead of Lord):
Baron: My Lord or Your Lordship or Lord (Name)
Viscount: My Lord or Your Lordship or Lord (Monckton in Chris’ case)
Earl: My Lord or Your Lordship or Lord (Name)
Marquess: My Lord or Your Lordship or Lord (Name)
Royal Family Members: Your Royal Highness.
Tom Schaefer
April 25, 2018 8:57 am
There is simply something wrong with anyone who would not be embarrassed by being addressed in such a way. Sic Semper Tyrannis.
Monckton of Brenchley
April 26, 2018 4:09 am
Mr Schaefer, being a colonial, is not as steeped in a thousand years of history, as we are in the Old Country. We like a little of the old-fashioned ways. However, many of our friends do not even know that I am Lord Monckton, for it is traditional not to stand too heavily on ceremony, and it is not done to introduce oneself as “Lord Monckton”, merely as “Monckton of Brenchley”. So, if Mr Schaefer does not wish to bow and scrape, he does not need to do so.
If we get a Communist government at the next election – and that is now a real possibility, for only the second time – I expect that a lot of this colorful but harmless and inexpensive flim-flam will be swept away. Will Britain be better for its passing? Probably not.
Monckton of Brenchley
April 24, 2018 2:55 pm
Most grateful to Chimp for his answer to Gus. I am the Queen’s seventh cousin twice removed (on the wrong side of the blanket, on my mother’s father’s side, via the Second Duke of Portland). So I am about 18 millionth in line to the Throne.
And yes, we are working on publication. There have been two previous papers working towards our current idea. The first was published in the Science Bulletin of the Chinese Academy of Sciences; the second was published in Energy & Environment. In due course we hope to get our result published in a leading journal of climatology. We do not underestimate the difficulties in overthrowing the Party Line by drawing attention to a very large error of physics, but we shall keep plugging away at it until either we are published or we are given good reason to apprehend that we are wrong.
Gus
April 25, 2018 4:13 am
I think, the party line is beginning to crumble already. Papers critical of it, in various ways, are being published even in Nature, Scientific Reports (a Nature publication), and Journal of Climate, the veritable party strongholds heretofore. On the other hand, geophysics and physics journals have always been more flexible here and have a history of publishing papers that openly pointed at errors in the party line, see, e.g., the two classic papers by Gerlich and Tscheuschner published in the International Journal of Modern Physics.
Regarding your idea of how to handle feedbacks, I recall a gentleman from Western Australia who worked on and published something quite similar a couple of years back. Also, there are papers by Ferenc M. Miskolczi, who analysed greenhouse in semi-transparent planetary atmospheres [1] that are well worth perusing.
[1] See, e.g., his paper on this in the Quarterly Journal of the Hungarian Meteorological Service, Vol. 111, No. 1, January-March 2007, pp. 1-40.
Monckton of Brenchley
April 26, 2018 4:04 am
Gus makes a very good point about the trend in equilibrium-sensitivity estimates in the learned journals. It is generally downward, and seems to be bottoming out at around 1 to 1.2 K per CO2 doubling.
However, I should be cautious before accepting the paper by Gerlich and Tscheuschner, which contains many errors and was published after inadequate review in a vanity-publishing predatory journal.
Miiskolczi’s paper is of more interest, but is just sufficiently complicated to have made very little general impression.
In my submission, our demonstration of a large, simple error – if no genuine fault is found with it – will have a more decisive effect in bringing official climatology to heel and moderating its current extravagant predictions.
April 28, 2018 11:19 am
Are we talking sensitivity to climate or titles?
HotScot
April 24, 2018 4:05 pm
Gus
your attempt at sarcasm by referring to Mr. Monckton as “Your Highness” is rude and disrespectful. Your constitution may be bound to disrespect the Aristocracy, but there is no need to wallow in your own righteousness.
I am a Brit, I respect the work Queen Elizabeth has done over the decades, through changing times, but I think the Royal family should be wound up and titles disposed of now. That does not mean I consider it clever to be spiteful.
So I refer to Mr. Monckton as, variously, Mr. Monckton, Christopher, or Chris.
Irrespective of how I refer to him, possibly much to his chagrin, I respect his decades long efforts to challenge alarmist science in it’s futile attempt to demonstrate that the future holds little but dystopia for us all.
If we were all as positive about the future as Chris Monckton, the world would be a better place. Fortunately he has the intelligence and education to present the science, to demonstrate that, logically.
He also has the courage to risk his reputation to do so.
I believe, that as a Scot, I am entitled to resent the Aristocracy at least as much as any other country in the world. It doesn’t, however, entitle me to be rude.
Monckton of Brenchley
April 24, 2018 4:19 pm
Most grateful to HotScot for his kind words. Of course he can call me “Mr Monckton” if he wants. That is a lot more polite than the epithets directed in my direction by the usual suspects. And of course HotScot does not really resent me, because it is not my fault I was born the grandson of a future Peer of the Realm.
But he has understood that we have proven that official climatology has been gravely in error for a century, and that after correction of that error it is not possible to make a credible case any longer for attempting to mitigate global warming, There will not be enough warming to matter.
HotScot
April 24, 2018 4:34 pm
Chris
“And of course HotScot does not really resent me, because it is not my fault I was born the grandson of a future Peer of the Realm.”
Quite true.
You long ago absolved yourself of that burden by your scientific endeavour.
🙂
Chimp
April 24, 2018 4:31 pm
I’m OK with granting titles in recognition of accomplishments, but agree that the coming Schleswig-Holstein-Sonderburg-Glucksburg dynasty is likely to be dreadful, starting with that irredeemable, insufferable twit Jug Ears. So retain titles but lose the reigning royal family.
Alfred the Great saw off the Danes from Wessex, but now a whole new Great Heathen Army threatens the realm. At least Elizabeth is half British and her Germanic dad was a loyal Briton, unlike his Teutonophilic older brother.
I’m not however a thorough-going republican. The UK could still be technically a monarchy rather than a presidential republic. Just extend the merit principle from Life Peers to the monarch. Let Parliament elect the most distinguished Briton of his or her generation (and who wants the job) to a lifetime tenure as king or queen and head of state of many Commonwealth nations, if they still want to go that route. Australia might finally balk at having Chuck the Cluck as its head of state.
Since most Britons are descended from Alfred the Great, King of Wessex, why not open up the position to talent rather than primogeniture?
HotScot
April 24, 2018 4:43 pm
Chimp
Sounds reasonable, but I maintain that any type of Monarchy in the UK is followed slavishly, and incorrectly, by despots across the globe announcing themselves King/Queen, dressing up in royal regalia and ‘ruling’ their countries as they imagine cartoon representations of our royal family do, by subjugation.
And now the ‘environmentalist’ and ‘architect’ Charles is being lined up as next king.
God help us, it’ll be wind turbines adorned with royal regalia next.
Chimp
April 24, 2018 4:46 pm
HotScot,
There really aren’t too many monarchies left, and many if not most of those have their own traditions, independent from Britain, the oldest being Japan’s.
HotScot
April 24, 2018 4:54 pm
Chimp
despots don’t do official monarchies, they just dress up, hold parades and beat people.
Is Kim Jong whatsit a monarchy? No, but the little despot dresses up (albeit in black) holds parades and beats people.
I could cite more starting with, perhaps, Idi Amine, the last king of Scotland. He dressed up, held parades and beat people.
That’s the perception of our royal family in some places, wrong of course. but it suites their purposes.
Chimp
April 24, 2018 5:06 pm
It has been a while since the British or English royal family behaved like Idi Amin, although conspiracy theorists think they bumped off Princess Diana.
But the family, if that it be, does have a long, sad, sorry, brutal history of treason, tyranny, greed, idiocy and lunacy, only partly redeemed by its few standouts. A chocking number of British monarchs couldn’t speak English. I don’t have enough time or space to say bad things about the Normans and Plantagenets. The Tudors were all terrible. police statists, except for the boy who died too young to burn his religious opponents alive, as he surely would have done. Three of the Stuarts were traitors. Charles I’s sons should both have been beheaded, too. The German-speaking Hanoverians depopulated the Highlands of your country.
I don’t think that even Edward I, Hammer of the Welsh and Scots, possibly the most competent English monarch after the House of Wessex, however was a cannibal.
MarkW
April 24, 2018 5:13 pm
Chimp, the problem there is that you might be condemning the country’s most talented mind to a ceremonial position with no real influence on anything.
Chimp
April 24, 2018 5:22 pm
Mark,
It would be a retirement job.
Somebody like BG Tony Wilson, CO of 5th Infantry Brigade in the Falklands War. He’s now 82, but would have been available at a younger, sprier age. He mostly did volunteer work after retirement.
His Royal Marines comrade MG Julian Thompson (3 Commando Brigade) is still writing at 83, however.
Chimp
April 24, 2018 5:26 pm
PS: The monarch is not totally without influence under the British constitution.
eddie willers
April 24, 2018 9:35 pm
Being an American I don’t really understand any of this Royalty biz, but I must say the current princess is popping out the cutest babies in Christendom.
Chimp
April 24, 2018 10:37 pm
Eddie,
The dynasty has belatedly awoken to the fact that they need to quit marrying inbred German aristos and strengthen the bloodline with common Brits.
Elizabeth by pure chance had a Scottish mum, because her dad wasn’t expected to be king. But his brother, the N@zi eldest son of a German dad, George V, and German mom, May of Teck, not surprisingly was pro-German rather than pro-British.
George Lawson
April 25, 2018 1:29 am
Chimp
. “Let Parliament elect the most distinguished Briton of his or her generation.to a lifetime tenure of king or queen”
So you think a political appointment would be better than what we have now? I can’t think of anything worse. While the current succession principal might leave a lot to be desired, a political appointment with multiple nominees and split votes in parliament just would not work, or have any purpose whatsoever. A political appointment would not be recognised by countries across the World as our current head of state does, and could quite easily result in the break up of the Commonwealth leading to unknown consequences, whereas our current system of a non-political royal head of state has served the country well over the years, and continues to attract respect and admiration from millions of supporters from across the World. It also attracts tens of millions of tourists to Britain to witness our royal pageantry, earning the country £billions to help our economy. Do you think someone like Branson or Lord Sugar, or some university boffin would do a better Job if they were elected? So don’t let short sighted ideals replace a system, which, for all its faults, has served us well as a nation state for many years..
HotScot
April 25, 2018 3:02 am
George
I don’t imagine for a moment the Commonwealth is held together by the royal family. It’s held together by trade.
And if the royal family is such a successful tourist attraction, make them a business and have them pay their own way. Of course, some competition might be healthy, but no doubt that would ruin the image of a royal head of the country, with unlimited wealth, paid by her vassals for her benevolence.
They might also want to hand back all the land and properties they earn income from, largely taken by force in the dim and distant past, whilst contributing their fair share of their tourism profits to the Treasury by conventional taxation.
Gus
April 25, 2018 4:32 am
Sorry, no sarcasm was intended. I genuinely didn’t know how to refer to Mr Monckton, knowing only that it’s quite complicated and varies depending on the title. Many thanks to Mr Chimp for the clarification. And, yes, there are constitutional provisions in the US about these things [1], though a particular 1810 amendment that threatened to strip Americans of their US citizenship if they dared accept a title of nobility from a foreign government has never been ratified and… is still pending, since no time limit for its ratification was ever set.
Nobody would remember about it, and nobody would care nowadays, were it not for the issue of emoluments that is tied to the same Article I, Section 9, Clause 8 of the US Constitution, and that has been dug out from the grave recently by some US politicians wishing to entangle President Trump in it.
[1] See, e.g., https://en.wikipedia.org/wiki/Title_of_Nobility_Clause
Chimp
April 26, 2018 12:18 pm
George Lawson April 25, 2018 at 1:29 am
An elected monarch would still allow all the pomp and ceremony which currently attracts tourists.
However it’s not clear to me that whatever revenue the monarchy generates covers the costs to the taxpayers of supporting this dysfunctional, often treasonous family.
Trevor
April 29, 2018 9:02 am
Och Aye !
James the 6th of Scotland became James ( the first ) of Great Britain ( England , Ireland and Scotland ).
So……………wi’ oot the Scots ( Stuarts ) there would nae ha been the Union !
So the Scots should show deference to what is the continuation of THEIR MONARCHY after all !
Anyway , that’s my story and I’m sticking to it !
M Courtney
April 24, 2018 1:23 pm
I fear this is the inverse of Exxon Knew.
Of course the evidence has been there all along. Every university has to teach that CO2 cannot cause a runaway feedback or it would have done with the first forest fire.
But that doesn’t mean they have to emphasise that commonly known fact. New calculations or not.
John Harmsworth
April 24, 2018 7:57 pm
Yes!
Clime-con knew?
Alan Tomalty
April 24, 2018 9:38 pm
It has been pointed out before that 97% of Antarctica never sees a positive temperature above freezing. In that 97%, there are 10 weather stations that have never seen any warming in their ~60 year history. Any greenie I ask How could Antarctica ever melt from global warming if the temperature never has gotten above freezing in 97% of the land mass? The other 3% is actually an island because the West Antarctica peninsula is actually an island. So mainland Antactica itself has never seen above freezing temperatures since Antarctica moved to the South Pole in the continental drift that took 100’s of millions of years. A secondary fact is that someone calculated in a WUWT article that it would take 105000 years to melt all the ice even if you had automated blowtorches. The greenies have no answer to this.
thomasjk
April 25, 2018 11:23 am
kim
April 24, 2018 1:23 pm
Yup, else why the narrative, the ’cause’.
=====================
Amber
April 24, 2018 1:28 pm
Thank you Mr. Monckton ! The “Exxon knew” .. slight of hand is a amateur distraction tactic to avoid exactly what you have outlined but there is no hiding any longer . Using and creating false information to defraud tax payers and other members of society is a crime long overdue to be prosecuted .
Tens of thousands of premature deaths from fuel poverty and $trillions blown on the biggest fraud in history . Justice will be served . Monckton of Brenchley Reply to Amber April 24, 2018 2:58 pm I agree with Amber. Mr Courtney, who says the CO2 cannot cause a runaway feedback, is addressing a point other than our point, which is that the non-runaway feedback imagined by official climatology is an order of magnitude too large, and we say we have proved that. If we have, then climate sensitivity cannot by any stretch of the most fevered totalitarian imagination exceed about 1.5 K, and is more likely to be around 1.2 K. The university in question now knows that this is true, but is continuing to gather grants on the basis of hoping that our result can be hushed up. Well, in the long run it can’t. Thanks to WattsUpWithThat, the truth is now available, and is slowly but surely making its way through the climatological community. M Courtney Reply to Monckton of Brenchley April 24, 2018 3:33 pm Yes. I acknowledge that the point I raise is not the point that you raise. But the implication is the same. Therefore the response would be the same. Thus the precedent has been set. They need to acknowledge the inconvenient facts (yours and those already known). But they don’t need to emphasise those facts. They have the right to say that some things are more important than other things. Even if we disagree. Monckton of Brenchley Reply to Monckton of Brenchley April 24, 2018 3:49 pm In reply to Mr Courtney, the university in question is entitled to its own opinions, but it is not entitled to its own facts. We say we have proven that official climatology has been overstating the feedback factor by an order of magnitude. If we have proven that, then it will no longer be open to any university to continue preaching the global warming nonsense, any more than it would be open to any university to preach that on the Euclidean or on the hyperbolic plane the square on the hypotenuse is not equal to the sum of the squares on the two catheti. Recall also that a jury, looking at the university’s conduct, would in my submission be readily satisfied of two facts: first, that the university knew perfectly well that we are right but chose to try to continue the scam; and secondly, that in practicing what it now knows to be a deception it is intending to enrich itself through hundreds of millions of dollars a year in global-warming funding, and to impoverish users of gasoline and electrical power through crippling taxation. The double-intent test having been satisfied, the jury would send the relevant personnel to the calabozo. It may yet come to that. Craig Reply to Monckton of Brenchley April 24, 2018 5:58 pm Serious question, are you concerned about these people coming after you physically? Do you have a security detail, body guards to protect against the threat of harm to you? Take this to it’s logical conclusion, you are threatening to bring down an industry worth trillions of dollars. Alan Tomalty Reply to Monckton of Brenchley April 24, 2018 9:44 pm Because there is so much money involved no one can trust any government agency on this. It has already been proven that GISS and NOAA have fudged and faked the data. I wonder why those agencies cant be prosecuted. We are living in a world of OZ. Monckton of Brenchley Reply to Monckton of Brenchley April 25, 2018 12:21 am Craig asks whether I am worried for my personal safety. No, for two reasons. First, thanks to WattsUpWithThat and its genial host and its competent mods I have now given enough detail about our result to ensure that, even if I were made a martyr for light and truth, the genie cannot now be forced back into the bottle. Secondly, though most climate fanatics know remarkably little science and are mere drones faithfully shrieking out the Party Line, the few who are driving this scam are cynical and experienced propagandists. They know that it is in their interest to keep me alive, for the danger in making martyrs is that it is usually the martyrs’ cause that prevails. Their answer, of course, is that I’m not a real Lord, I’m not a real scientist, I’m not a serious contributor to the debate, there’s no debate anyway, the science is settled, so I don’t matter, so why should they waste a bullet? Y. Knott Reply to Monckton of Brenchley April 25, 2018 7:10 am Take this to it’s logical conclusion, you are threatening to bring down an industry worth trillions of dollars. Yes – delightful isn’t it, especially when the dollars in question come out of our pockets at gunpoint? And the value to humanity of the “industry” being negative – Bastiat’s candlemakers’ petition illustrating – we the outsiders are all the better-off therefore, I hope. It’s not like there aren’t many other ‘interested motives’ tugging-at the pursestrings, or won’t be lots more after this one, or that the Gummint will responsibly use any savings that result… Sometimes I despair of our Race. Well Done, Lord Monckton! – and if you’re in my neck o’ the woods and need a bit o’ muscle at your back, I imagine I could rustle-up a friend or two to help keep the forces of darkness at bay… { – and yes Craig, I know you meant it positively! – } Monckton of Brenchley Reply to Monckton of Brenchley April 25, 2018 10:44 am Many thanks to Mr Knott for his kind words. It is people like him, who are generous enough to let me know they are grateful, who help to offset the rancorous poison of the climate fanatics. Roger April 24, 2018 1:33 pm I’ve read several of these feedback posts from Christopher Monckton of Brenchley and still lack any real understanding of what is being said. I am not an electrical engineer (Chem Eng) and am unfamiliar with electrical engineering feedback. Maybe that is my problem. But my understanding of feedback in the climate models is that they postulate that the initial CO2 caused increase in temperature increases the water vapor which further increases the temperature. Missing hot spot says this is debatable. But is this the same feedback that Christopher is talking about where the feed back response is directly caused by the input variable (Temp) and not by a follow on effect? Latitude Reply to Roger April 24, 2018 1:43 pm woops…….. Reply to Latitude April 24, 2018 3:02 pm What matters is absolute humidity. According to NASA/RSS satellite measurements, global average WV has been increasing 1.5% per decade for at least as long as it has been measured (since Jan 1988). Rational extrapolation indicates 8% since 1960. Both WV and UAH temperature are now (thru Mar 2018) below their trend lines. D. J. Hawkins Reply to Latitude April 24, 2018 3:10 pm The proper measure is absolute humidity. If I have a parcel of air at 70F and 50% relative humidity and raise the temperature to 85F with 45% relative humidity, the line between those points for RH will show a negative slope. However, the actual water content for the former is 55.7 grains of H2O per pound of dry air and the later will be 82.8 grains per pound. The total water content of the air has increased. It may come to the same thing in the end, depending on the actual temperatures at those elevations for the period of interest, but we should always be careful to talk about what really matters. Latitude Reply to Latitude April 24, 2018 3:20 pm how about specific humidity….. Josh C Reply to Latitude April 24, 2018 5:36 pm Ah…. IIRC, what matters is humidity at the 300mb level, where the increased CO2 is supposed to ‘gather’ and retain the most heat? If there is to be a ‘Santer’ style fingerprint, it would be an increase of Water Vapor at 300mb, increasing the CO2 forcing. Please, correct me if I am wrong. Latitude Reply to Latitude April 24, 2018 6:57 pm how about specific humidity at 300mb……………..grrrrrrrrrrrrrrrrrrrrr!! Latitude Reply to Latitude April 24, 2018 7:03 pm Latitude Reply to Latitude April 24, 2018 7:04 pm Alan Tomalty Reply to Latitude April 24, 2018 9:54 pm Mr Pangburn where do you get that water vapour info. That is completely false. NASA had a project to measure it for 20 years and couldnt prove any increase so Hansen shut the project down in 2009. Alan Tomalty Reply to Latitude April 24, 2018 10:05 pm The following is from an article by Ken Gregory that was published on WUWT “NASA satellite data shows a decline in water vapor Guest Blogger / March 6, 2013 Global water vapor Global water vapor (Photo credit: oakridgelabnews) Guest post submitted by Ken Gregory, Friends of Science.org An analysis of NASA satellite data shows that water vapor, the most important greenhouse gas, has declined in the upper atmosphere causing a cooling effect that is 16 times greater than the warming effect from man-made greenhouse gas emissions during the period 1990 to 2001. The world has spent over$ 1 trillion on climate change mitigation based on climate models that don’t work. They are notoriously poor at simulating the 20th century warming because they do not include natural causes of climate change – mainly due to the changing sun – and they grossly exaggerate the feedback effects of greenhouse gas emissions.
Most scientists agree that doubling the amount of carbon dioxide (CO2) in the atmosphere, which takes about 150 years, would theoretically warm the earth by one degree Celsius if there were no change in evaporation, the amount or distribution of water vapor and clouds. Climate models amplify the initial CO2 effect by a factor of three by assuming positive feedbacks from water vapor and clouds, for which there is little direct evidence. Most of the amplification by the climate models is due to an increase in upper atmosphere water vapor.
The Satellite Data
The NASA water vapor project (NVAP) uses multiple satellite sensors to create a standard climate dataset to measure long-term variability of global water vapor.
NASA recently released the Heritage NVAP data which gives water vapor measurement from 1988 to 2001 on a 1 degree by 1 degree grid, in three vertical layers.1 The NVAP-M project, which is not yet available, extends the analysis to 2009 and gives five vertical layers.
From the NVAP project page:
The NASA MEaSUREs program began in 2008 and has the goal of creating stable, community accepted Earth System Data Records (ESDRs) for a variety of geophysical time series. A reanalysis and extension of the NASA Water Vapor Project (NVAP), called NVAP-M is being performed as part of this program. When processing is complete, NVAP-M will span 1987-2010. Read about changes in the new version.
Water vapor content of an atmospheric layer is represented by the height in millimeters (mm) that would result from precipitating all the water vapor in a vertical column to liquid water. The near-surface layer is from the surface to where the atmospheric pressure is 700 millibar (mb), or about 3 km altitude. The middle layer is from 700 mb to 500 mb air pressure, or from 3 km to 6 km attitude. The upper layer is from 500 mb to 300 mb air pressure, or from 6 km to 10 km altitude.
The global annual average precipitable water vapor by atmospheric layer and by hemisphere from 1988 to 2001 is shown in Figure 1.
The graph is presented on a logarithmic scale so the vertical change of the curves approximately represents the forcing effect of the change. For a steady earth temperature, the amount of incoming solar energy absorbed by the climate system must be balanced by an equal amount of outgoing longwave radiation (OLR) at the top of the atmosphere. An increase of water vapor in the upper atmosphere would temporarily reduce the OLR, creating a forcing of more incoming than outgoing energy, which raises the temperature of the atmosphere until the balance is restored.
NVAP_pwv
Figure 1. Precipitable water vapor by layer, global and by hemisphere.
The graph shows a significant percentage decline in upper and middle layer water vapor from 1995 to 2001. The near-surface layer shows a smaller percentage increase, but a larger absolute increase in water vapor than the other layers. The upper and middle layer water vapor decreases are greater in the Southern Hemisphere than in the Northern Hemisphere.”
The graphs didnt show up but you can read the article here
https://wattsupwiththat.com/2013/03/06/nasa-satellite-data-shows-a-decline-in-water-vapor/
Monckton of Brenchley
April 25, 2018 12:44 am
I am most grateful to Latitude for his series of water vapor plots, and to Mr Tomalty for pointing out that the upper troposphere, where 90% of the feedback-amplifying effect of water vapor is supposed to occur, is not showing any increase in specific humidity – one important reason to suspect that the water vapor feedback has been overvalued by official climatology.
April 25, 2018 10:07 am
AT – Numerical data of the NASA/RSS satellite measurements is reported at http://data.remss.com/vapor/monthly_1deg/tpw_v07r01_198801_201803.time_series.txt
The data is graphed at Figure 3 in my blog/analysis.
April 25, 2018 11:19 am
AT – On reading your longer post above, I see we are very much on the ‘same page’. Because most of the WV is below about 10 km (above 265 mb) where TPW is increasing perhaps these two NASA reports are not in significant disagreement.
I differ with your (and IPCC) assumption that CO2 has a significant influence on temperature; especially the assumption that warming was initiated by CO2. I list at least six examples of compelling evidence that CO2 has no significant effect on temperature (or any other aspect of climate). My assessment is that warming was initiated by solar change and the change is signaled by the proxy of sunspot numbers.
I would like to pursue this further but a cursory search revealed nothing on NVAP after 2009. Do you have a link to anything more recent? The NASA/RSS data is current.
Gary Pearse
April 24, 2018 2:14 pm
It’s both the input and the add on. By ignoring the former (The big one: 255K (what we would have with no GHG) ), the total feedback is attributed only to the GHG giving rise to the 288C present global average T. Therefore climate folks are attributing a value 10x too large to increasing CO2’s effect on temperature.
ggm
April 24, 2018 3:00 pm
I’m struggling to follow this. Is my simple explanation below accurate :
The Earth would be -18 degrees C (255 K) if it had no atmosphere. But Earth’s atmosphere raises the temperature to +15 degrees C (288 K) average via the natural greenhouse effect. This 33 degree C/K increase is why Earth isn’t frozen solid.
NOW we have AGW theory which says that increasing CO2 will cause a 1 degree increase in temperate from the CO2. This 1 degree increase will cause a massive feedback with water vapor which will then add another 4+ degrees for every degree of CO2 warming.
If this feedback were true, then the same feedback MUST exist with the original 33 degree increase – in which case the world would be 132 degrees warmer than it is. The “feedback” does not have intelligence to know that it should only happen for human produced CO2 – it’s either a real physical process, or it’s not.
The fact that the Earth is not boiling, means there is no massive H2O feedback.
The fact that these crooks knowingly ONLY apply this feedback to the CO2 warming, but NOT to the original 33 degree warming means that they KNOW they are committing fraud (or that they are incredibly incompetent)
Did I get that right ?
April 24, 2018 4:00 pm
ggm…”did I get that right?”
I hope you got it right because that is also my understanding. If increased water vapor is linearly proportional to increased temperature, it matters not what caused the increase in temperature (e.g. Milankovitch cycle). Although the above analysis began at the end of the little ice age in the mid 1800s, the analysis could have begun at the end of the ice age 10,000 years ago and the result would be similar although CO2 would not be significantly involved.
Monckton of Brenchley
April 24, 2018 4:11 pm
Gary Pearse has got it right, but ggm not quite. The argument is that if 12 K of warming induces a feedback response, then the original 255.4 K emission temperature must also induce a feedback response. Thus, official climatology says that the feedback fraction is 1 – 12 / 32 = 0.63, while we say, in line with established control theory, that 1 – (255.4 +12) / 287.5 = 0.07. The emission temperature is the input temperature in the feedback circuit, and, even if there were no mu amplification to allow for the presence of the naturally-occurring, non-condensing greenhouse gases, there would be a feedback response to emission temperature, so that the output signal – i.e., equilibrium temperature, would be higher than the emission temperature.
And nobody here need apologize for finding all of this is hard to follow. Feedback math is notoriously counter-intuitive, which is one reason why official climatology’s grave error of physics has gone undetected until now.
April 24, 2018 4:50 pm
Since natural variability is poorly understood, many things can and do effect equilibrium temperature, and CO2 is nowhere to be found in the loop equation, how do we know that CO2 is causing temperature and not just correlating with temperature. I keep running into the problem that all the proxy data I have seen shows temperature leading CO2 or they are uncorrolated ( example). Couldn’t you run the same analysis using albedo for example.
ggm
April 24, 2018 4:58 pm
Another thing to note is that in Earth’s geologic history, temperatures have never correlated with CO2 levels.
For example :
Cretaceous : 145–66 million years ago
https://en.wikipedia.org/wiki/Cretaceous
CO2 = 1700ppm (6 times pre-industrial level)
Temperature = 18C (4 degrees above today)
Jurassic : 201.3–145 million years ago
https://en.wikipedia.org/wiki/Jurassic
CO2 = 1950ppm (7 times pre-industrial level)
Temperature = 16.5C (3 degrees above today)
Permian : 298.9–251.902 million years ago
https://en.wikipedia.org/wiki/Permian
CO2 = 900ppm (3 times pre-industrial level)
Temperature = 16C (2 degrees above today)
Carboniferous : 358.9–298.9 million years ago
https://en.wikipedia.org/wiki/Carboniferous
CO2 = 800ppm (3 times pre-industrial level)
Temperature = 14C (0 degrees above today)
Silurian : 443.8–419.2 million years ago
https://en.wikipedia.org/wiki/Silurian
CO2 = 4500ppm (16 times pre-industrial level)
Temperature = 17C (3 degrees above today)
Chimp
April 24, 2018 5:12 pm
Cambrian: over 17 times present level, but only seven degrees warmer (maybe a lot less on average).
Ordovician: 10.5 times current CO2, but at most only 2 °C above modern temperature on average. But it ended with an ice age.
mynaturaldiary
April 25, 2018 12:11 am
In reply to ggm and his excellent points, I would recommend if you have a spare 45 mins (sic) you watch this episode ‘The Big Freeze’ from the ‘Earth Story – Aubrey Manning’ series on geology.
This details climate change over geological time, and includes the effects of tectonic drift, the long term carbon cycle and Milankovic cycles and their separate effects.
The program ends with the statement that ‘climate change is an inevitable consequence of the way the Earth works. The climate has been changing one way or another throughout the history of the planet, and will continue to do so.’
http://www.dailymotion.com/video/x1d52hx
WXcycles
April 25, 2018 6:45 am
@ Chimp
Such comparisions will be highly altered by geodynamic ocean and land geography configurations, plus by high mountain ranges affecting both moisture and global circulation.
.
Monckton of Brenchley
April 24, 2018 3:01 pm
In reply to Roger, the models indeed assume that the non-condensing greenhouse gases induce a warming that in turn induces a feedback response. However, the models have not been trained to take account of the fact that the pre-existing emssion temperature also induces a feedback response, via just the same feedback processes as drive the feedback response to the small warming caused by the non-condensing greenhouse gases. And what that means is that the feedback factor is an order of magnitude smaller than official climatology thinks. And what that means is that doubling CO2 will cause about 1.2 K warming – at most around 1.5 K. Not the 3.3 K that is the models’ current central estimate. Certainly not the 10 or 11 K on the basis of which scientifically illiterate governments currently make climate policies.
HotScot
April 24, 2018 4:30 pm
Chris
in my utter ignorance, as a layman, all I know is that CO2 has risen from an almost catastrophically low 180ppm some time ago (about 30ppm away from the extinction of meaningful life) to 400pp now.
I find it astonishing that sometime during that period, mankind happened along, discovered fire, then the means to extract and utilise fossil fuels (which were naturally, but accidentally sequestered) which in turn, gradually helped to restore the atmospheric balance to something approaching normal, and coincidentally, helped mankind progress to the point that we can tap on our computers and communicate almost instantly across the globe.
That’s a miracle by any standards, not that I’m religious.
Personally, I would like to see CO2 levels at around 1,500ppm, allowing us a little wriggle room. If that has the consequence of raising temperatures, perhaps it might liberate the billions of acres of unusable land lost to permafrost across Siberia and Canada.
As it is, NASA tells us that the only observable manifestation of increased atmospheric CO2 is that the planet has greened by 14% in 30 years, including equatorial deserts.
Sorry if this is cutting across you Chris, but I’m a layman, and I like things presented in practical terms, as valuable as your science is.
My belief is also that you and your fellow academic colleagues could do well by transmitting the practical benefits of increased CO2 in layman’s terms. There’s a lot more of us ignorant prole’s out there with votes than there are scientists with votes.
Thank you for your work. It’s much appreciated by this prole.
Monckton of Brenchley
April 24, 2018 4:48 pm
Most grateful to HotScot for his further thoughtful reply. I agree that the oil, coal and gas corporations ought to have found the courage to point out the benefits of their product. The greening of the planet, as seen from space, is quite spectacular.
However, our approach in the present study is to demonstrate conclusively that the entire concern about runaway, catastrophic global warming was based on a fundamental error of physics and that, when the error is corrected, the global warming problem vanishes.
The value of this approach is that, once our paper is published, official climatology will be compelled to respond. It will not be able to ignore our result. IPCC will have to take account of it in its next assessment report. And that, really, will be the end of the scare.
Our program of study thus concentrates not on propaganda for CO2 – that is the business of the oil, coal and gas corporations, though they have been shockingly lackadaisical about it – but on nailing down the science so that there is absolutely no wriggle-room for the Forces of Darkness. We are close to achieving that objective. If we succeed, the news of our result will have a far more powerful effect than any mere propaganda campaign.
April 24, 2018 5:56 pm
The IPCC included the emission temperature feedback (Planck feedback it is described as) as one of the feedbacks in its latest report.
But it is NOT included in the theory or the climate models.
Just show the page where this is shown and ask climate scientists how it changes the math and why it cannot possibly be included.
mynaturaldiary
April 25, 2018 12:31 am
Monckton of Brenchley – as a fellow Brit, you may be interested in this – a rigorous multiple regression model for the Central England Temperature, which looks at a number of factors.
https://mynaturaldiary.wordpress.com/2018/03/03/whither-the-weather-2/
This would suggest that a CO2 rise of 285ppm would give 1.71 K temperature rise, which again is far less than formal climate science is predicting.
The model presented suggests unsurprisingly that the monthly CET depends mostly on last month’s solar insolation, followed by influences on the Jet Stream and it’s position over the UK as influenced by teleconnections such as the Arctic Oscillation etc, and finally by a faint CO2 trend.
I am also very happy to swear allegiance to Her Majesty, her heirs and descendants.
Monckton of Brenchley
April 25, 2018 12:49 am
In reply to Mynaturaldiary, it is interesting that most empirical derivations of equilibrium sensitivity find it to be of order 1.5 K, so the 1.7 K result is in line with these derivations. Unfortunately, there are a lot of uncertainties in the empirical approach, which is why we have taken a theoretical approach, proving that climate sensitivity is low. The Central England temperature record is particularly prone to uncertainty, particularly before 1950.
mynaturaldiary
April 25, 2018 1:45 am
Monckton of Brenchley – The monthly model presented only uses the data from 1950 onwards for the reasons you highlighted. I agree empirical regression models have a limit, but they contain all the data. As more becomes available, the process is simply repeated to confirm the trends highlighted. repeating this approach at points around the earth where robust data is available would serve to act a bit like thermocouples inside a chemical reactor – point source measurements that any global theoretical model must explain.
A robust theoretical scientific model is of course gold standard, but as you have highlighted, the current ‘gold standard models’ have a fatal flaw in them. It remains to be seen whether the scientific community accept your argument and then incorporates it into its own models. It strikes me we are at a stage of Kuhn’s structure of scientific revolutions viz.
‘Normal scientific progress can be viewed as “development-by-accumulation” of accepted facts and theories. Kuhn argued for an episodic model in which periods of continuity in normal science were interrupted by periods of revolutionary science, leading to new paradigms.’
So your work may lead to a new paradigm. I expect that it would take the incorporation of your work into a climate science model, and ten extra years of observation to confirm to begin to change the minds of the scientific-political machine in motion.
I personally agree whether by regression or climate feedback there is less to worry about than the current ‘gold standard models’ suggest. In answer to your question ‘Did official climatology know its predictions were nonsense?’ if it didn’t before, it does now.
Kristi Silber
April 25, 2018 3:39 pm
HotScot,
“As it is, NASA tells us that the only observable manifestation of increased atmospheric CO2 is that the planet has greened by 14% in 30 years, including equatorial deserts.
Do they?
https://climate.nasa.gov/evidence/
lewispbuckingham
April 24, 2018 3:03 pm
For my non mathematical mind, the ‘fixed’ amount of heat, which delivers a temperature before anthropogenic CO2 is added, is of itself, the product of feed back, so, therefore also itself varies, dampening increase in temperature negative feedback , as further CO2 is added to the atmosphere .
Monckton of Brenchley
April 24, 2018 3:17 pm
Lewis Buckingham is right. The emission temperature of 255.4 K is dependent only upon insolation and albedo, so it has been affected by the melting of the great ice sheets, which is of course a feedback process. But once the temperature reaches 255.4 K, even if there are no non-condensing greenhouse gases it continues to be affected by the water vapor feedback, which is currently thought to be the largest of all the feedbacks.
jorgekafkazar
April 24, 2018 9:02 pm
My understanding has been that the trougherati assume that there is no global warming from water vapor until CO2 is accounted for, that water vapor heating is then solely the result of CO2.
Monckton of Brenchley
April 25, 2018 12:50 am
jorgekafkazar is correct: official climatology imagines, in effect, that there was no water vapor in the atmosphere and no ice to melt in the oceans until CO2 came along. That’s why it has ignored the actually quite large feedback response to emission temperature.
April 25, 2018 1:59 am
official climatology imagines, in effect, that there was no water vapor in the atmosphere and no ice to melt in the oceans until CO2 came along.
Imagine the mental contortions in which one has to engage in to draw such an inference from mainstream statements like the following 2010 Lacis et al. paper’s comment about the effect that the loss of noncondensing greenhouse gases:
A direct consequence of this combination of
feedback by the condensable and forcing by the
noncondensable constituents of the atmospheric
greenhouse is that the terrestrial greenhouse effect
would collapse were it not for the presence of
these noncondensing GHGs. If the global atmospheric
temperatures were to fall to as low as TS =
TE, the Clausius-Clapeyron relation would imply
that the sustainable amount of atmospheric water
vapor would become less than 10% of the current
atmospheric value. This would result in (radiative)
forcing reduced by ~30W/m2, causing much
of the remaining water vapor to precipitate, thus
enhancing the snow/ice albedo to further diminish
the absorbed solar radiation. Such a condition
would inevitably lead to runaway glaciation,
producing an ice ball Earth.
Monckton of Brenchley
April 25, 2018 10:50 am
The Born Liar, in his desperation to land a blow on our result regardless of considerations such as the mere objective truth, purports to jib at my statement that official climatology imagines, in effect, that there was no water vapor in the atmosphere and no ice to melt in the oceans until CO2 came along. The ineluctable consequence of official climatology’s definition of a “climate feedback” as a response only to a perturbation in global temperature is that its models take insufficient (or, in many instances, no) account of the feedback response to emission temperature. That refusal to take due account of that large feedback response is tantamount to a declaration that the feedback processes – notably the water vapor feedback – do not exist in the absence of the non-condensing greenhouse gases. Do the math.
April 25, 2018 11:32 am
The ineluctable consequence of official climatology’s definition of a “climate feedback” as a response only to a perturbation in global temperature is that its models take insufficient (or, in many instances, no) account of the feedback response to emission temperature.
Note that Lord Monckton has again trimmed his sails; he now allows that models may actually have taken feedback to emission temperature into account; he merely thinks their doing so was “insufficient” in his view. But how would he know?
Also, Lord Monckton continues to conflate small-signal quantities with large-signal ones. He refers to definitions that deal with linearized, small-signal quantities and thinks the modelers apply them to (highly nonlinear) large-signal behavior.
When the literature speaks of “perturbations,” it’s referring to small departures from a nearby reference state. Lord Monckton has produced no evidence for the proposition that the reference state was arrived at by ignoring feedback to the reference-state temperature. For all he knows, in fact, the reference-state values may have been obtained by observation of actual-climate-system-results at which the Great Modeler arrived by including such feedback in His calculations.
Monckton of Brenchley
April 25, 2018 3:14 pm
The Born Liar continues to snipe spitefully, and to disregard the truth, which is that right from the start I cited Lacis (2010), who, without specifically mentioning the feedback response to emission temperature, nevertheless seemed to allowed for an unrealistically small one.
It is, however, quite clear that the definition of a “climate feedback” given by official climatology excludes the possibility of any feedback response to emission temperature. It is still clearer from our calibration of the zero-dimensional-model equation that one can reproduce official climatology’s interval of Charney sensitivities solely by assuming a feedback fraction that takes no account whatsoever of the feedback response to emission temperature. That is one of the reasons why we carried out the calibration: precisely to discover to what extent, if any, allowance had been made for the feedback response to emission temperature.
And we know from the university’s consternation on first hearing of our result that it is by no means as easy to dismiss as the Born Liar so dearly wishes.
April 26, 2018 8:46 am
From Lacis 2010:
” Thus, while the non-condensing greenhouse gases account for only 25% of the total greenhouse effect, it is these non-condensing GHGs that actually control the strength of the terrestrial greenhouse effect since the water vapor and cloud feedback contributions are not self-sustaining and as such, only provide amplification.”
“only provide amplification”
I’m sorry, this is just plain wrong. Photons travel at the speed of light, and they just don’t care whether they come from a “fast acting” condensing gas or a (by implication) slower acting noncondensing gas. Water in the atmosphere is not solely dependent on CO2 back radiation.
Thank you Mr.Born for bringing up Lacis 2010, so as to remind us that the objection raised by Monckton is by no means the ONLY failing of the models. Treatment of atmospheric water as feedback only, failure to account for the low emissivity of CO2, et al mean that the true sensitivity to doubling is much closer to 1 degree, and values below 1 degree can not be ruled out.
Sweet Old Bob
April 24, 2018 1:40 pm
Time for more e-mails to fly ….
and to be released ……. 8>))
April 24, 2018 1:41 pm
I conclude that the estimates of ECS are a worst case model, as it assumes the sole influence on temperature are greenhouse gases. If there is some other factor influencing historic temperature changes, the sensitivity to changes in CO2 would be less to the degree those other factors have an influence.
As variations in CO2 did not correlate to the LIA, or the 1945-1975 dip in temperature, there is some other factor in play. The problem is determining what those other phenomena are.
Monckton of Brenchley
April 24, 2018 3:03 pm
In reply to Mr Halla, official climatology’s estimates of equilibrium climate sensitivity cover a wide interval, and are designed to represent all possibilities, not just the extreme case. We have demonstrated that the two-thirds to nine-tenths of the officially estimated equilibrium sensitivities that are supposedly accounted for by feedback processes have been very greatly exaggerated. So there will not be up to 11 K warming per doubling of CO2: there will be about 1.2 K.
April 24, 2018 1:44 pm
Interesting. The illustrations are Goebbels’ Propaganda Ministry in Berlin and Kim Il Sung Square in Pyongyang 😉
April 24, 2018 1:48 pm
So what was the uni’s technical result of so much professorial work the grad students went on strike? If your leak is as good as it appears, you should be able to get it. Unless you have been set up …….
Monckton of Brenchley
April 24, 2018 3:04 pm
In reply to Mr Proctor, the university is still scratching its collective noddle.
HotScot
April 24, 2018 4:45 pm
Chris
that’s incredibly polite of you. I imagine their scratching is about a meter lower than their noddle.
April 24, 2018 2:01 pm
“How long has official climatology known of its grave error? In truth, the vast majority of the pietistic preachers of doom and gloom have never had the slightest idea what they were talking about.”
It is interesting that on the same day, WUWT publishes this rant and a much more scientific (and published) analysis by Nic Lewis, who takes no notice of this claim of “grave error”.
[Well Nick, see here’s the thing. We don’t care what you think is “interesting” -Anthony]
J
April 24, 2018 2:22 pm
While they don’t mention the “grave error” their published results based on data agree with the message from Lord Monckton, the climate sensitivity is lower than the alarmists of IPCC have promulgated.
April 24, 2018 2:34 pm
“While they don’t mention the “grave error””
The “grave error” is presumably not including a feedback to emission temperature. They don’t do that. So it isn’t just that they don’t mention it. They “commit” it.
But of course, L&C are not in “grave error”. They just do sensible energy budget study, get a result at the low end of the IPCC range, but with big error ranges (which is the cost of the budget approach).
Latitude
April 24, 2018 3:09 pm
“The “grave error” is presumably not including a feedback to emission temperature.”
Then what is it Nick?
kim
April 24, 2018 2:27 pm
I would celebrate the day Nick Stokes accepts a non-alarmist value for sensitivity.
==================================
Monckton of Brenchley
April 24, 2018 3:10 pm
By now Mr Stokes knows full well that official climatology, on which he has hitherto hung his hat, has perpetrated a grave error, and that without that error there would not be enough globakl warming to be worth worrying about. But he is, of course, right that the very large uncertainties inherent in any attempt to derive equilibrium sensitivities empirically will result in absurdly wide error margins unless one does what Lewis & Curry have not done and derives equilibrium sensitivity theoretically from three less uncertain numbers: the emission temperature 255.4 K, the directly-forced warming of about 12 K from the presence of the naturally-occurring, non-condensing greenhouse gases, and the natural surface temperature of 287.5 K in 1850. The feedback factor is then 1 – (255.4 + 12) / 287.5, or about 0.07. Even if it were four times that, Charney sensitivity would be only 1.4 K.
Serge Wright
April 24, 2018 3:27 pm
The Lewis paper is only concerned with plotting temperature and CO2 changes since 1850 and calculating an ECS derived from observations. Their much lower ECS compared to that provided by the IPCC is not considered in their paper. Some grave error must exist to explain this large disrepancy.
Monckton of Brenchley
April 24, 2018 3:52 pm
Mr Wright is right. It has become increasingly difficult to justify IPCC’s high-sensitivity case as evidence of the continuing failure of the world to warm at anything like the predicted rate. But what we submit we have done is to find the central reason for the models’ extravagant over-predictions: namely, the elementary error of physics by which the feedback response to emission temperature has been overlooked and undervalued.
April 24, 2018 4:32 pm
“The Lewis paper is only concerned with plotting temperature and CO2 changes since 1850 and calculating an ECS derived from observations. Their much lower ECS compared to that provided by the IPCC is not considered in their paper. “
They use the full range of radiative forcings. Their abstract begins
“Energy budget estimates of equilibrium climate sensitivity (ECS) and transient climate response (TCR) are derived based on the best estimates and uncertainty ranges for forcing provided in the IPCC Fifth Assessment Scientific Report (AR5).”
But critically, they include an estimate for heat flux into the ocean, which gives them an effective sensitivity.
Their ECS is not “much lower” than that provided by the IPCC. The AR5 range was from 1.5 to 4.5 °C/doubling. They get 1.5, 1.66 or 1.76, depending on dataset used and allowance for varying feedback. But even the lowest estimate has 2.45 as the upper end of its uncertainty range.
The key thing is that they do not use the “emissivity temperature” feedback, which Lord M says it is a grave error to omit.
Monckton of Brenchley
April 25, 2018 12:54 am
As Mr Stokes will recall from earlier threads in this series, one can derive estimates of equilibrium sensitivity empirically without knowing what the feedback sum is. So Lewis & Curry, taking an empirical approach, committed no error in neglecting the feedback response to emission temperature. Their mid-range estimate of Charney sensitivity does not differ greatly from ours, but their upper bound of 2.45 K, considerably below the 9.2 K in their earlier paper, is an important new constraint. I am looking forward to studying their paper to learn more.
HotScot
April 24, 2018 4:47 pm
Nick
how about, Chris Monckton speaks his mind.
Gerald Machnee
April 24, 2018 8:27 pm
Stokes:
**WUWT publishes this rant**
What is a rant, Nick?
April 24, 2018 10:49 pm
Nick would know – he is an expert ranter.
April 25, 2018 6:17 am
A rant is most closely aligned to what I typically post. Nick on the other hand just babbles sciencey sounding nonsense not founded in reality
commieBob
April 24, 2018 2:03 pm
This looks like it could eclipse climagegate.
As Bill Clinton and Martha Stewart and others discovered, the punishment for trying to cover something up is much greater than the punishment for the original incident.
I’m putting in a supply of popcorn and beverages. This could be highly entertaining.
Monckton of Brenchley
April 24, 2018 3:12 pm
Hurrah for Commiebob. This is indeed going to be worth watching. At the moment, we are taking the cautious approach of checking everything many times. But once we are sure we are right we shall publish, and once we have published there will no longer subsist even the vestige of a pretext for suggesting that global warming will be a global crisis. If we’re right, it’s all over bar the shouting. There will be quite a lot of that, as the totalitarians come to terms with the magnitude of the error of physics right at the heart of their case. But the word is already inexorably spreading. The end is in sight.
Chimp
April 24, 2018 3:23 pm
While awaiting publication and appearances on Fox News and coverage from Breitbart, how about preparing a YouTube video for mass consumption, explaining your discovery simply and graphically?
commieBob
April 24, 2018 3:39 pm
Godspeed.
April 24, 2018 3:42 pm
Dear Mr. Monckton,
I want to address you as Lord, as that was my initial knowledge, yet I still don’t understand why that is no longer applicable. Regardless, thank you.
I have a question regarding your certainty that this curtain will fall, most specifically because of the worldwide push for collectivism, totalitarianism, cessation of free speech and thought, etc. This is the foundation these new high priests set up to control the population though energy, especially the internet of things and how that interacts with smart technology, and how that is the foundation of agenda 21/ 2030.
I mention this context because the very loud, very red suspects (slate, guardian, intercept, CNN, MSNBC, VOx, BBC, etc) have been very effective with the propaganda. The universities, doing their part have crippled the minds of the youth. While I appreciate your positive assurances, I’m left wondering what can someone like myself do, or those of us also not suffering from group think… What can we do to actually combat this and ensure you are correct?
I’ve seen only sparsely populated efforts from anyone left of center to break away from said group think, topically at great cost to those livelihood. If what you say is indeed true and this will crumble, what measures can be taken to ensure you are correct?
I talk about this with everyone. I’m that guy. I mention this topic daily to strangers, to get a pulse, and what I see is blind Faith based on ignorance that rivals even the best ancient religions.
Additionally, facts don’t matter to neo-Marxist part modernist acolytes. A personal acquaintance after been thoroughly educated about the lack of truth regarding CO2 then moved the goal post saying “why should I care? I agree with all the measures they want to implement.”
This isn’t atypical behavior; this is the standard.
Granted, I won’t be there least surprised if you respond with dismissal assuming I’m just a negative cynic (which, admittedly, I sway greatly to that mentality), but I should also say I’m genuinely continuing to hold out hope in these dark times and want to actively assist in breaking down these inhuman falsehoods. I’m currently at a loss as to how or whether my efforts actually contribute.
I welcome criticism and suggestions
Alan Tomalty
April 24, 2018 10:28 pm
Chris Could you please explain this sentence.
“We know that IPCC currently imagines that the CO2-driven warming should be increased by 35% to allow for all other anthropogenic forcings, so that the directly-forced warming from all natural sources was about 12 K.”
I was following your analysis up to there but got lost at this point. In that sentence arent you still talking about 1850? As another aside could you please add (CO2….etc) at the end of the words “non condensing greenhouse gases” wherever they may appear in any future report.
Monckton of Brenchley
April 25, 2018 12:58 am
I should certainly not dismiss honestliberty as a cynic. It is realistic to expect that the usual suspects will snap and snarl and wriggle and duck and dive. But what we have found is a formal demonstration that official climatology has been in error for more than a century; that the error is elementary and grave; and that after correction no one would worry about dangerous manmade global warming. If we are wrong, then our paper will vanish or, if published, be trumped by later papers. If we are right, however, then official climatology is going to have to change its view. It cannot deliberately pretend that it can get away without taking due account of the feedback response to emission temperature once the world knows that in fact it must take due account of it. That is the value of a mathematical demonstration. No one would now dare to argue that on the Euclidean or on the hyperbolic plane the square on the hypotenuse of a right triangle is not equal to the sum of the squares on the two catheti.
Monckton of Brenchley
April 25, 2018 10:54 am
Mr Tomalty asks the sensible question how I arrived at the notion that official climatology currently imagines that the CO2 forcing should be uplifted by about 35% to account for the forcing from the other non-condensing greenhouse gases (notably methane). IPCC (2013, fig. SPM.5) shows that the mid-range estimate of the CO2 forcing to 2011 was 1.68 W/m^2, while the mid-range estimate for the net anthropogenic forcing from all sources was 2.29 W/m^2, and 2.29 is about 36% greater than 1.68. And he makes a fair point that I should explain which the non-condensers are.
TRM
April 24, 2018 2:08 pm
Love it. Thank you for your continued efforts. The information war is being won.
Not that I suspect lord Monckton has a mischievous “Calvin & Hobbes” side to his personality but could he have been the one who “leaked” it to them just for kicks and giggles? My mind works that way 🙂
Monckton of Brenchley
April 24, 2018 3:14 pm
TRM credits me with a Machiavellian cunning that I, a simple bumpkin, do not possess. Somehow a copy of our result found its way to the university, whose vice-chancellor’s panicky, hysterical reaction, followed by his refusal to let me face his faculty to defend our result and his head of publicity’s lies to a foreign journalist, tells any disinterested observer that They know the game is up.
TRM
April 24, 2018 6:15 pm
You are many things sir but a “simple bumpkin” you assuredly are not. Cheers and keep up the great work.
richard
April 24, 2018 2:14 pm
UEA
Monckton of Brenchley
April 24, 2018 3:18 pm
You might think that, but I couldn’t possibly comment.
timbrom
April 24, 2018 4:52 pm
Bwahaha!
jorgekafkazar
April 24, 2018 9:37 pm
Quite so.
richard
April 25, 2018 12:52 am
hmm, that is along the lines of ” i saw all the planes take off and I saw all the planes return”
Steve Ta
April 25, 2018 2:33 am
Can’t be UEA – which does have a Conservative Association on campus
richard
April 24, 2018 2:14 pm
UAE
April 25, 2018 3:48 am
united arab emirates?
richard
April 24, 2018 2:18 pm
oops thought it didn’t go through and then letters went haywire.
Chimp
April 24, 2018 2:26 pm
Dunno if that’s UEA or not, but the bottom image is of Kim Il Sung Square, Pyongyang.
commieBob
April 24, 2018 2:48 pm
Bingo. link The caption provided by CM was: “Not a blade of grass to gladden the students’ eyes in the eco-fraudsters’ paradise” Okay then …
Monckton of Brenchley
April 24, 2018 4:20 pm
You can have fun trying to work out what the first of the two illustrations is.
Chimp
April 24, 2018 4:38 pm
Looks to me like the German Ministry of Finance building, except for the grass and trees. But maybe they’re on the side away from the street.
It doesn’t look anything at all like most UEA structures, which are ziggurat-like stepped semi-pyramids of a type usually found in urban seaside resorts, like those above Playa Larga in Reñaca, Chile, between Viña del Mar and Concón.
April 24, 2018 4:49 pm
It’s not UEA. Seven storey ashlar building? not too many of those on UK campuses. And I don’t think anything in the UK was designed by Albert Speer either 🙂
Chimp
April 24, 2018 4:56 pm
Here’s an overhead shot, which makes me think even more that it’s the German Finance Ministry building, a relic of N@zi architecture (but not Speer’s), originally the Third Reich’s Air Ministry.
https://en.wikipedia.org/wiki/Detlev-Rohwedder-Haus
If I’m right, then Chris has connected National Socialist with monarchical Communist architecture, hence with CACA totalitarian ideals.
Chimp
April 24, 2018 4:58 pm
PS: Also East German, since the DDR Commies used it.
April 24, 2018 4:59 pm
The first picture is Goebbels’ Propaganda Ministry
Chimp
April 24, 2018 7:28 pm
Kevin,
OK. Similar architectural style.
ggm
April 24, 2018 7:55 pm
Wrong. It isn’t the building in Germany. Just do a google for “Detlev-Rohwedder-Haus” and go to the Google Maps street view of the building, and you will see that this is definitely not the German building.
Chimp
April 24, 2018 8:04 pm
Ggm,
If it were the German finance ministry building, the view posted by Chris would be of an interior courtyard, not the street level view.
Nigel S
April 25, 2018 4:27 am
The courtyard in the centre of the picture matches pretty well, including the narrow windows each side.
April 24, 2018 2:23 pm
“A temperature feedback, in W m–2 K–1 of the output (equilibrium temperature), induces a feedback response in Kelvin that modifies the output even where the input (emission temperature) was unamplified.”
This is totally inconsistent with the diagram below it, which shows nothing marked in Wm⁻². It’s all T. The feedback shown is β Teq, where β is dimensionless.
But the last caveat “even where the input (emission temperature) was unamplified” makes no sense. The device has an amplifier which applies a gain to the inout. Feedback modifies the input to the amplifier, applying a gain to the modification too. If the input is unchanged (emission temperature), there is no change it can apply that gain too. So no feedback loop.
Monckton of Brenchley
April 24, 2018 3:25 pm
In reply to Mr Stokes, official climatology defines a temperature feedback as a temperature-dependent forcing denominated in Watts per square meter per Kelvin. Taking the product of the feedback sum and the Planck parameter gives the unitless feedback factor, represented by mu * beta in the diagram. The feedback response beta * equilibrium temperature is of course in Kelvin, because, though beta is unitless, the equilibrium temperature is in Kelvin.
Mr Stokes appears unfamiliar with the scientific method. If one wants to establish whether the input signal in a feedback amplifier circuit is itself responsible for engendering a feedback response in the presence of a non-zero feedback fraction beta, a powerful method is to set the direct-gain or open-loop gain factor mu to unity (i.e., no amplification), and then to run the circuit. If the output signal differs from the input signal, then even the unamplified input signal is generating a feedback response.
We built not one but two test rigs, both of which – as one of the many tests we ran – were set to have an input signal and a nonzero feedback fraction. And both of them produced output signals greater than the input signal, just as theory would lead us to expect. One realizes that feedback theory is notoriously counter-intuitive, which is why we built test rigs and played with them till we gained some feel for how feedback works.
Serge Wright
April 24, 2018 3:47 pm
LM, I’ve been following your posts and can see that many people are not realising that 255K is an output driven by an input that is part of the same feedback loop equation. To clarify your point, would it be fair to suggest that the current IPCC inteprepation of the feedback loop equation would only hold true at 0K, where no output signal exists ?.
Monckton of Brenchley
April 24, 2018 4:02 pm
In response to Mr Wright, the 255.4 K emission temperature is the input signal. In the absence of any mu amplification or beta feedback fraction it would also be the output temperature: in other words, with no non-condensing greenhouse gases and no feedback processes (such as the ice-albedo and water-vapor feedbacks) the Earth’s surface temperature would be 255.4 K. Now, set the beta feedback fraction to 0.07. Then, even with no mu amplification (i.e., with mu := 1), the output signal would be 274.6 K, an increase of 19.2 K. Now add 12 K warming by putting in the naturally-occurring, non-condensing greenhouse gases. Now the mu amplification factor becomes 1 + 12 / 255.4 = 1.047, and the output becomes 255.4 x 1.047 / (1 – 0.07) = 287.5 K, from which one can deduce that the feedback response to the presence of the non-condensing greenhouse gases is not about 20 K, as the current erroneous method suggests, but just 0.9 K.
April 24, 2018 4:10 pm
“official climatology defines a temperature feedback as a temperature-dependent forcing denominated in Watts per square meter per Kelvin”
It certainly doesn’t define feedback as a forcing. It takes great pains to distinguish between forcing and feedback. But yes, it can make sense to treat the feedback as a temperature dependent flux. It makes more sense than your treatment of the “standard zero-dimensional-model equation” in the figure, which shows no fluxes (Wm⁻²) at all. But it requires that the input is a flux, and “emission temperature” does not qualify.
This is why it is useless making these airy statements about “official climatology” without quoting what they actually say. Not only do you get it wrong, but it is hopelessly inconsistent.
Monckton of Brenchley
April 24, 2018 5:21 pm
Mr Stokes continues to have difficulty with elementary concepts in control theory as applied to the climate. Ordinary radiative forcings are denominated in Watts per square meter. Feedback forcings are radiative forcings denominated in Watts per square meter of the temperature to which they induce a response. The distinction between the two types of forcing is that the amplitude of the feedback forcing is temperature-dependent.
Contrary to Mr Stokes’ assertion that I have not cited my sources, in previous postings I have listed the climate-relevant feedbacks, denominated – whether he likes it or not – in Watts per square meter per Kelvin, and I have stated that my source (admittedly not peer-reviewed in any recognizable sense) is IPCC. Since the feedbacks are denominated in Watts per square meter per Kelvin, they are responding to temperature and temperature change in Kelvin, and not directly to a radiative flux.
Mr Stokes would perhaps gain a better understanding of these elementary concepts if he were to read a pedagogical paper such as Roe (2009). Roe, of course, perpetrates the same error as the rest of official climatology, but at least he explains that feedbacks are denominated in Watts per square meter per Kelvin.
Let me again recapitulate the terminology I am using. There seems to be no standard terminology, so I take a “temperature feedback” or “feedback” or “feedback forcing” to be denominated in Watts per square meter per Kelvin; I take the “feedback fraction” beta to be the unitless fraction of the output signal returned from the output node via the feedback loop to the input node; I take the “feedback factor”, f in official climatology, mu x beta in control theory, to be the product of the mu direct-gain or open-loop gain factor and the beta feedback fraction; and I take the “feedback response” to be the temperature response in Kelvin to a temperature feedback.
Mr Stokes says he would prefer the feedback loop to be denominated in Watts per square meter (which he calls a “flux”, though one supposes he means a “flux density”). Well, the point is that feedbacks are denominated in Watts per square meter per Kelvin of the temperature to which they respond. Therefore, it makes sense to do what official climatology usually (though not always) does and denominate the input and output temperatures in Kelvin.
Mr Stokes wonders where the feedbacks in Watts per square meter per Kelvin are in the feedback loop. As I have already explained, if one takes the product of the feedback sum in Watts per Kelvin and the Planck reference-sensitivity parameter in Kelvin per Watt per square meter one obtains the feedback factor mu x beta, which is official climatology’s f. In earlier pieces in this series, this was made plain in the table of feedbacks.
Therefore, our approach is rigorously consistent with that of official climatology, except where we have demonstrated that official climatology is in error.
April 24, 2018 6:36 pm
“Contrary to Mr Stokes’ assertion that I have not cited my sources”
No, I said you have not quoted what they say. You never do. We only hear your version.
Monckton of Brenchley
April 25, 2018 1:00 am
Mr Stokes says I have not cited the sources I have mentioned, in particular on the question whether official climatology denominates temperature feedbacks in Watts per square meter per Kelvin. In not one but two earlier postings, I reproduced IPCC’s own table of temperature feedbacks thus denominated, and I explained exactly where in the Fifth Assessment Report that table appeared.
April 25, 2018 3:10 am
“Mr Stokes says I have not cited the sources I have mentioned”
Wearily, again, no, I said you don’t quote them. And this is typical
“In not one but two earlier postings, I reproduced IPCC’s own table of temperature feedbacks thus denominated”
No, you didn’t reproduce their table. You put together this table
That is not a reproduction. It does incorporate the totals and ranges of feedbacks from the AR5 table. That table did not have the timescale descriptors. But more importantly, you have added the feedbacks and their bound limits. The AR5 did not do that.
Now adding the mean values is reasonable. But adding the bounds is certainly not. The upper bound of cloud, say, is 1.0 Wm⁻²/K (you said 1.1). That means there is a 95% chance that the true value is less than 1.0. And so for the bounds of wv, etc. But for the sum to be less than the sum of the bounds, each would have to be in the high end of the range, and the chance of that is far less than 5%.
And then you criticised them for the excesses of the range. In fact, if the uncertainties are independent, the uncertainties should be added in quadrature.
OK, that’s just an error. But it isn’t the AR5’s error, and we have no way of knowing that. The reason is that you don’t quote what they say.
And so it is with this “grave error”. You never say who is actually making it in estimating ECS. You say that Nic Lewis’ result is immune. So what about all the other studies?
Monckton of Brenchley
April 25, 2018 10:59 am
Mr Stokes now concedes, in effect, that contrary to his earlier assertion I had indeed cited IPCC as my source for the denomination of feedbacks in Watts per square meter per Kelvin. But he complains that I have displayed the stated bounds explicitly. That is purely a matter of layout. He also complains that I have added the IPCC’s timescales for each feedback. So what? Finally, he complains that one should not simply add the upper bounds to obtain an upper bound for the feedback sum and for the feedback fraction. Let him tell that to the climate fanatics who have been doing just that, and have been telling us that, therefore, runaway feedback is possible.
April 25, 2018 1:05 pm
“Let him tell that to the climate fanatics who have been doing just that”
And yet again, no quotes. Scientists do not add error bounds to get the error bound of a summed quantity. That is an elementary error. A Monckton special.
Monckton of Brenchley
April 25, 2018 4:19 pm
Let us look at some of the errors perpetrated by the determinedly ignorant Mr Stokes in this thread alone:
Item: Mr Stokes says that the mid-range estimate of 1.5-1.76 K Charney sensitivity in Lewis & Curry (2018) is not much lower than that of IPCC. Actually, IPCC made no mid-range estimate in its Fifth Assessment Report, but previous reports had found the mid-range estimate to be 2.5-3.5 K, and the CMIP3 and CMIP5 models take a mid-range estimate of 3.3 K.
Item: Mr Stokes says that the feedback response shown in the circuit diagram in the head posting is in Kelvin, while feedback processes are denominated in Watts per square meter per Kelvin. He is unaware that the feedback factor mu x beta is also the unitless product of the Planck parameter (denominated in Kelvin per Watt per square meter) and the feedback sum (denominated in Watts per square meter per Kelvin). As Mr Stokes so often and so unpleasantly does, he alleged that I had erred and, in doing so, merely exposed the depth and breadth of his own ignorance.
Item: Mr Stokes says Watts per square meter do not appear anywhere in the feedback loop diagram. Of course they don’t, because temperature feedbacks are – er – feedbacks responding to temperature, not to fluxes. That is why official climatology denominates feedbacks not in Watts per square meter per Watt per square meter but in Watts per square meter per Kelvin.
Item: Mr Stokes says there is no feedback loop if there is no mu amplification. There is. We tested it. It is inherent in the correct form of the zero-dimensional-model equation.
Item: Mr Stokes imagines that if the emission temperature, the input signal to the feedback loop, is unchanged there is no feedback response. There is. We tested it. It is inherent in the correct form of the zero-dimensional-model equation.
Item: Mr Stokes says official climatology does not define feedback as a forcing. Yet it does: it is a forcing denominated not in Watts per square meter, as direct forcing are, but in Watts per square meter of the temperature that induces it.
Item: Mr Stokes whines that I had not cited my source for the fact that feedbacks are denominated in Watts per square meter per Kelvin. When I pointed out that I had done so, and that it was IPCC, he protested that IPCC’s table does not have timescales mentioned on it. But IPCC had given timescales for the feedbacks in a separate table, and I had combined the two.
Item: Mr Stokes did not like my summing the upper bounds of IPCC’s estimates of the principal climate-relevant feedbacks to show that they summed to unity, which would imply runaway feedback. When I said that climate fanatics frequently say that runaway feedback will arise, he said I had not cited any climate fanatics. Let him do a little work of his own, for a change, instead of trying to be pathetically negative. Let him look up “runaway climate feedback” on the internet and he will see just how often this absurd notion is stated by climate fanatics.
Item: Mr Stokes cited IPCC on the supposed “consistently important feedback” from water vapor, but without mentioning that nine-tenths of the water-vapor feedback in the models is supposed to occur in the mid to upper troposphere, where nearly all datasets, both satellite and radiosonde, do not show the repeatedly model-predicted doubling or tripling in the tropical mid-troposphere of the surface warming rate.
Item: Mr Stokes says it does not make sense to speak of feedback to an unchanging property (in the climate, that is emission temperature, which is not quite an umchanging property, but never mind). Like it or not, feedback response to emission temperature can and does occur, but is largely – if not entirely – overlooked by official climatology.
And the accident-prone Mr Stokes whines that I have made an “error”. Bah! Pshaw!
April 25, 2018 5:31 pm
“Item: Mr Stokes says that the mid-range estimate of 1.5-1.76 K Charney sensitivity in Lewis & Curry (2018) is not much lower than that of IPCC.”
Aha! A quote. Well, almost, but lacking quotes. What I said was
“Their ECS is not “much lower” than that provided by the IPCC. The AR5 range was from 1.5 to 4.5 °C/doubling. They get 1.5, 1.66 or 1.76…”
Clearly true. L&C are within the IPCC range.
“Item: Mr Stokes says that the feedback response shown in the circuit diagram in the head posting is in Kelvin, while feedback processes are denominated in Watts per square meter per Kelvin.”
Yes. And it’s true! And I noted that the diagram immediately followed Lord M’s definition that said it should be so. There is no mention of any flux-denominated quantity in the diagram. The definition of μ as 1+ΔTref/Tref is clearly unitless, and β likewise.
“Item: Mr Stokes says Watts per square meter do not appear anywhere in the feedback loop diagram.”
Indeed so.
“Item: Mr Stokes says there is no feedback loop if there is no mu amplification. “
Again, quote needed. I did not say that. I said that an essential requirement of a feedback loop is that the output can modify the input. Which it can’t if the input quantity is unchanging.
“Item: Mr Stokes says official climatology does not define feedback as a forcing. “
I pointed out (with quote) that OC takes pains to distinguish between forcing and feedback. To refute that, a quote of OC actually defining feedback as a forcing is needed. Having units of Wm⁻² does not make something a forcing.
Speeding up a bit, I’ll just say that “runaway feedback” is in no way equivalent to adding bounds; the issue of whether specific humidity is rising is contentious, but in no way contradicts the proposition that wv is a “consistently important feedback” ; and the last is just relitigating the posts.
Monckton of Brenchley
April 26, 2018 3:58 am
Mr Stokes wriggles, but unavailingly. His errors are errors, and some of them are strikingly elementary.
Item: As other commenters here have pointed out, if Lewis & Curry are right that the mid-range estimate of Charney sensitivity is of order 1.5 K, then the models’ current mid-range sensitivity of 3.3 K is very much too high. Of course Lewis & Curry’s mid-range estimate is lower than that of IPCC. To point out that it is still (just) within IPCC’s interval of possible sensitivities is a mark of desperation.
Item: Mr Stokes now knows perfectly well that the feedback factor f in official climatology (like mu x beta in all other dynamical systems) is the product of the Planck parameter, denominated in Kelvin per Watt per square meter, and the feedback sum, denominated in Watts per square meter per Kelvin. It is, therefore, perfectly viable to do the entire calculation based on the unitless feedback fraction, without having to convert it to a feedback sum. Mr Stokes errs by quibbling pointlessly.
Item: Mr Stokes says Watts per square meter do not appear anywhere in the feedback loop diagram, implying that this is somehow reprehensible. Well, it isn’t. Official climatology’s version of the zero-dimensional-model equation uses temperature changes in Kelvin as as its input and output, because feedbacks are denominated in Watts per square meter per Kelvin. Since the produce of the feedback sum thus denominated and the Planck parameter in Kelvin per Watt per square meter is unitless, the equation does not require any of its quantities to be denominated in Watts per square meter or Watts per square meter per Kelvin. And Mr Stokes knows this perfectly well. This is one of many instances of wilful but unsuccessful misdirection on his part.
Item: Mr Stokes says that an essential requirement of a feedback loop is that the output can modify the input, which it cannot if the input quantity is unchanging. Dear, oh dear. If a mu amplification amplifies the input, the input is unchanged but the output differs from the input. If a beta feedback fraction modifies the output, the modified output is fed back to the input node, thence via the mu gain block to the output node. But, when we talk of a mu amplification or a beta feedback fraction modifying the input, the modification is manifested as a change not in the input but in the output. Follow the direction of the arrows.
Item: Mr Stokes says official climatology does not define feedback as a forcing. Let him look up the definition of a radiative forcing. It is an exogenous change in the net down-minus-up radiative flux density at the top of the atmosphere. It is denominated in Watts per square meter. Let him look up the definition of a temperature feedback. It is denominated in Watts per square meter per Kelvin. It is thus a forcing: just like a direct forcing, it is an exogenous change in the net down-minus-up radiative flux density at the top of the atmosphere. But, unlike a direct forcing, it is scaled to the temperature that induced it. Don’t be silly.
Item: Mr Stokes says the issue of whether specific humidity is rising is contentious but in no way contradicts the proposition that water vapor is a “consistently important feedback”. Again, don’t be silly. Nine-tenths of the water vapor feedback is supposed to arise in the mid- to upper troposphere, where, particularly in the tropics, the resultant warming is supposed to be twice or thrice the surface warming. Yet NOAA’s specific humidity record, like nearly all such records, shows no increase in specific humidity in the upper or mid-troposphere. On this evidence, nine-tenths of the imagined water-vapor feedback is non-existent, making it an unimportant feedback
hunter
April 24, 2018 2:36 pm
When is the study expected to be published?
Monckton of Brenchley
April 24, 2018 3:27 pm
How long is a piece of string? We are expecting a very great deal of scrutiny, and probably a lot of sneering from official climatology. But we shall pay no attention to that. Instead, we shall look very carefully at any points that the reviewers make, and we shall respond constructively. If the reviewers discover a fatal flaw in our result, then that will be that. If not, then in due course we hope that one or other of the major climate journals will have the courage and intellectual honesty to publish our paper.
NorwegianSceptic
April 25, 2018 6:49 am
” If the reviewers discover a fatal flaw in our result, then that will be that.”
And You call this ‘Climate Science’?! 😉
As a layman I will not pretend to understand all the underlying physics in the article, but i gives me a better hope of exposing the AGW sc@m.
All the best m’lud !
Roger Knights
April 26, 2018 10:41 am
CMoB: “in due course we hope that one or other of the major climate journals will have the courage and intellectual honesty to publish our paper.”
If one of them doesn’t, that would look bad. It would retroactively taint all of “settled science.”
I suspect what they’ll do is line up several “refutation” papers to be published in the same issue. If they don’t they’ll be badly berated by the establishment’s mind guards.
Monckton of Brenchley
April 26, 2018 2:07 pm
In response to Mr Knights, we already know that the dirty-tricks department is at work, because a copy of our paper found its way to the university whose Vice-Chancellor, instead of asking the question, “Is this true?”, instead ordered his entire enviromental-sciences faculty to refute it, for our result, he said, was “a catastrophe”. And so it will prove to be, for that university is one of many that receives huge subsidies from various sources for researching what the vice-chancellor and his faculty now know full well is a non-problem.
You can bet that the midnight oil is being burned as the Forces of Darkness try to find a strategy for containing what, to the rest of the world, is excellent news, but what, to them, is, as the vice-chancellor said it was, a catastrophe for the unholy coalescence of financial vested interests that has profiteered for decades by peddling this pointless scam.
But the truth is now public, thanks to our kind host here, and the genie cannot be put back in the bottle. We have revealed enough of our result to allow any honest enquirer to see what we have done and to understand why and how we have done it. The truth can initially be denied: but, in the long run, it cannot be prevented. Magna est veritas, et praevalet.
Jeff Cagle
April 24, 2018 2:49 pm
@ Nick, anyone with specific EE experience.
The issue as I understand it is this. Any positive feedback in an audio amplifier (my frame of reference for these things) very quickly causes squeals. That’s because positive feedback is modeled by diffEQ whose eigenvalues have positive real parts, and are thus unstable. The slightest noise leads to asymptotic growth in output.
Now, if the climate system has positive feedback in the same sense as an audio amplifier (and here, I plead ignorance), then we would already be living on Venus II. The slightest temp rise should lead to ever-greater temps, leading to exponential temp growth.
The fact that this does not happen leads inevitably to the conclusion that our climate system is modeled by diffEQ whose eigenvalues have nonpositive real parts.
But my reasoning may be faulty because I might be misunderstanding positive feedback in this context. Correction is welcome.
April 24, 2018 3:18 pm
“Any positive feedback in an audio amplifier … very quickly causes squeals.”
No, you need enough positive feedback. There is a threshold, depending on gain. Any PA system has positive feedback at some frequency ranges (speaker to microphone), but it can function quite well. It’s only when you turn up the gain beyond a certain level that you get squeals.
commieBob
April 24, 2018 4:22 pm
True. It’s very common to do some kind of stability analysis on systems that have feedback. An example is root locus analysis for control systems. A similar analysis is done for high frequency amplifiers where the feedback path is an unavoidable result of device parameters.
It is possible to design a system to deliberately use positive feedback. eg. regenerative receiver The thing is that electronic circuits can have carefully controlled parameters. The climate … not so much. If positive feedback actually existed in the climate system, as proposed by Hansen et al, it is inevitable that the parameters would, from time to time, line up in such a manner as to induce instability. We would notice that.
It has been my observation that folks experienced in working with practical feedback systems usually find Hansen’s analysis objectionable. CM’s brilliant coup is to accept, assuming arguendo, the analysis as given and demonstrate its fatal flaw.
Monckton of Brenchley
April 25, 2018 1:02 am
Most grateful to Commiebob for his exceptionally kind comment. We have indeed accepted the case advanced by the Forces of Darkness ad argumentum, and have then pointed out a startling illogicality in it. One cannot lpgically get away with assuming that 255.4 K of emission temperature induces no feedback, but that a mere 12 K of additional temperature suddenly induces a very large feedback.
Monckton of Brenchley
April 24, 2018 3:32 pm
In reply to Mr Cagle, process engineers designing electronic feedback-amplifier circuits to avoid runaway feedback in the presence of componentry of variable quality and uncertain operating conditions will often try to ensure that the feedback fraction is <0.1, and often less than 0.01.
The feedback fraction assumed by official climatology is of order 0.67-0.76. This is far too high a value to guarantee stability, because at that region of the rectangular-hyperbolic response curve the temperature rapidly heads in the direction of infinity. It was that observation that first led me to look at how official climatology was handling feedbacks.
The value of the feedback fraction that we have deduced – around 0.07 – has a much better chance of allowing relatively stable conditions to continue, and it removes the supposed risk of reaching a "tipping point" in global temperature.
Monckton of Brenchley
April 24, 2018 3:43 pm
In response to Jeff Cagle, process engineers designing feedback amplifier circuits to operate stably with componentry of variable quality and in uncertain operating conditions will often design in a feedback fraction of not exceeding 0.1, or even 0.01 if they can manage that, precisely to avoid problems of instability arising from runaway feedback. Sure enough, the Great Designer has built the world on similar lines, with a natural feedback factor of 0.07.
April 24, 2018 3:46 pm
Nonpositive real eigenvalues are not inconsistent with positive feedback in this case. We have inner and outer loops
The inner loop is like this:
$C\dot{y}=x-y/\lambda_0,$
whose eigenvalue is obviously nonpositive for $\lambda_0>0$. But we’re dealing with equilibrium conditions, for which $\dot{y}=0$, so $y=\lambda_0x$ in the inner loop. Then we add an outer loop resulting in $y=\lambda_0(x+fy)$ for the equilibrium equation. Even if feedback is positive, i.e., even if $f>0$, the system is stable so long as $1-\lambda_0f$ is positive.
Alan Tomalty
April 24, 2018 10:52 pm
If y dot = 0 then x-y = lambda * 0 Therefore x = y in your inner loop. I stopped reading at that point.
April 25, 2018 2:40 am
If y dot = 0 then x-y = lambda * 0 Therefore x = y in your inner loop.
$\dot{y}=0$ implies $0=x-y/\lambda_0$
Adding $y/\lambda_0$ to both sides gives you:
$y/\lambda_0= x$
Now here’s the tricky part. You have to multiply both sides by $\lambda_0$. That’s what results in:
$y=\lambda_0x$
Sorry if I was obscure. I know math isn’t everyone’s cup of tea.
Monckton of Brenchley
April 26, 2018 3:35 am
If the product of the Planck parameter 0.3125 Kelvin per Watt per square meter and the feedback sum 3.2 Watts per square meter per Kelvin is unity, the system will be very unstable. If the feedback sum approaches 3.2, or if the feedback factor approaches unity, transient instabilities could fling the system into disorder. However, our result indicates that feedback factors anything like as high as the 0.75 imagined in Lacis (2010), or the 0.67 implicit in the CMIP5 models’ mid-range estimate of 3.3 K Charney sensitivity, are not going to arise.
s-t
April 24, 2018 6:04 pm
I was quite convinced by the “science” of climate (as in, I don’t have time to recheck it, I don’t go to the restaurant to cock myself) … and then I became aware that they used a big positive feedback in their model.
It isn’t something they used to advertise a lot 15 years ago.
s-t
April 24, 2018 7:14 pm
@mod
You can remove this one!
s-t
April 24, 2018 6:04 pm
I was quite convinced by the “science” of climate (as in, I don’t have time to recheck it, I don’t go to the restaurant to cook myself) … and then I became aware that they used a big positive feedback in their model.
It isn’t something they used to advertise a lot 15 years ago.
April 24, 2018 8:29 pm
They don’t “use” a big positive feedback in their model. GCMs solve the system of flow and heat transfer. You can interpret what that produces as a positive feedback, but that is an outcome, not an input.
As to what they said 15 years ago, here is the AR3, 2001, 7.2.1.1:
“Water vapour feedback continues to be the most consistently important feedback accounting for the large warming predicted by general circulation models in response to a doubling of CO2. Water vapour feedback acting alone approximately doubles the warming from what it would be for fixed water vapour (Cess et al., 1990; Hall and Manabe, 1999; Schneider et al., 1999; Held and Soden, 2000). Furthermore, water vapour feedback acts to amplify other feedbacks in models, such as cloud feedback and ice albedo feedback. “
Alan Tomalty
April 24, 2018 11:40 pm
Well Nick it had better result in a huge positive feedback in the models or else you couldnt get enough of a temperature increase from increased CO2 alone. Dont forget the man made industrial change in net CO2 is only 410ppm-300ppm(the year 1950 amount) = 110ppm Even if all of that 110 ppm was dumped in the atmosphere at once it all wouldnt stay as witnessed by since 1980 fossil fuels have increased 75% and net CO2 in atmosphere has increased only 21 %. This is assuming of course that the infrared way of calculating average CO2 is correct versus the original wet chemical technique which all chemists say is superior to the infrared method used at Mauna Loa. So indeed hidden in every computer climate model code is a sensitivity fudge that does model runs based on CO2 doubling. They didnt have that fudge code in the early days but they soon discovered that they couldnt either hindcast or forward cast and get results that were not meaningless. Every modeller will tell you that their code is based on Navier- Stokes flow dynamics but you also need radiative heat transfer equations to solve it, Because their cloud modelling is so useless they dont even try to use radiative heat transfer equations but just use fudge factors. A good thing too because even if they were able to model clouds perfectly the radiative heat transfer equations are even more complicated than the Navier Stokes equations. I will quote from the world’s authority on Radiative heat transfer Michael Modest. In the following quote he is is only talking about 1 aspect ie; emissivity.
” It is apparent that the calculation of total emissivities is far from an exact science and carries a good deal of uncertainty. The reader should understand that accurate emissivity values are difficult to measure and that too many parameters are involved …….”
In the case of considering collisions of gaseous molecules one is led to the Voight profile equation on page 319 of Modest’s book. In it he states “No closed form solution exists for the Voight profile.
So Nick the models are left with having to fudge.
And we base the taxation of CO2 on this????????????
Alan Tomalty
April 24, 2018 11:50 pm
It seems the 1950 figure for CO2 is 310ppm.
April 25, 2018 12:04 am
“So indeed hidden in every computer climate model code is a sensitivity fudge that does model runs based on CO2 doubling.”
There is nothing hidden in the code. Many of them are available to see and download. Here is CAM. You can register, download, compile and run it, as many have. For GISS Model E, no registration is needed, and they will even give you today’s version.
“Every modeller will tell you that their code is based on Navier- Stokes flow dynamics but you also need radiative heat transfer equations to solve it, Because their cloud modelling is so useless they dont even try to use radiative heat transfer equations but just use fudge factors.”
No, they solve radiative transfer (they have to). Here is the CAM 3.0 documentation of how it is done.
Monckton of Brenchley
April 25, 2018 1:26 am
Mr Tomalty is, of course, correct. Neither the Lorentzian nor the Voigt partial-differential equation has a closed-form solution. Both equations are notoriously intractable: and yet they are simplifications, assuming as they do that collisions between photons and molecules occur instantaneously, when in truth there is a detectable delay, which – in the opinion of Professor Happer – is insufficiently accounted for by modelers, leading to a 40% overstatement of the CO2 forcing.
Though Mr Stokes is correct that models do not explicitly incorporate the Bode feedback formulism, it is used in official climatology to derive the equilibrium sensitivities that models might be expected to predict. Our calibration of the zero-dimensional model, which is an attempt to embody that formulism, shows that it does indeed reproduce faithfully the official interval of Charney sensitivities provided that it is informed with the official values of the reference sensitivity and the feedback fraction that are derived from the models in, for instance, Vial et al. (2013). It is clear from that and many suchlike papers that the processes in the models have the effect of implying a feedback fraction that is about an order of magnitude larger than it would be if proper account had been taken of the feedback response to emission temperature.
bit chilly
April 25, 2018 4:56 pm
if that is the case nick ,where is the hot spot in the troposphere ?
Roger Knights
April 26, 2018 10:48 am
I was quite convinced by the “science” of climate … and then I became aware that they used a big positive feedback in their model.
It isn’t something they used to advertise a lot 15 years ago.
“the supposed positive feedback from water vapor [is] a weak link in their chain of evidence ….” IOW, it’s the key to the whole climate controversy:
2/20/13, David Evans 12 minute video: “The skeptics’ case”— 484,000 views.
https://youtu.be/0gDErDwXqhc
“Every serious skeptical climate scientist has been consistently saying essentially the same thing for over 20 years, yet most people have never heard the message. … The government climate scientists and the media often tell us about the direct effect of tt CO2, but rarely tell us that two-thirds of their projected temperature increases are due to amplification by feedbacks.
…………….
“The climate debate is all about the feedbacks; everything else is merely a sideshow. Yet hardly anyone knows that. The government climate scientists and the media have framed the debate in terms of the direct effect of CO2 and sideshows such as arctic ice, bad weather, or psychology. They almost never mention the feedbacks.”
Bill Gray argues similarly:
https://wattsupwiththat.com/2018/01/18/flaws-in-applying-greenhouse-warming-to-climate-variability-a-post-mortem-paper-by-dr-bill-gray/
As does Willis Eschenbach:
https://wattsupwiththat.com/2018/02/05/a-hard-rains-gonna-chill/
Kristi Silber says:
Probably no discussion of the amount of carbon dioxide contributed to the atmosphere from the burning of Amazonian rainforest, …
OTC, that’s just the sort of alarmist sideshow that they might well include.
Monckton of Brenchley
April 26, 2018 2:02 pm
Mr Knights makes an excellent point. it is the supposedly large water vapor feedback that official climatology uses as its chief pretext for two-thirds to nine-tenths of the equilibrium sensitivity that models predict. There is little theoretical justification and no empirical justification for a water vapor feedback as large as that which official climatology imagines, and I am reasonably confident that there would have been no attempt to put forward so large a water vapor feedback if official climatology had not been misled by its elementary error of physics.
Geo
April 24, 2018 2:53 pm
Not tooting my own horn here, but I did a much more primitive version of this calculation back in 2012. Carbon dioxide concentrations have increased since 1950 from 270 ppm to 400 ppm, or 130 ppm, which is a 48% of the first doubling. Ergo, assuming everything is proportional, the temperature increase to date should be 48%*1.3 degrees = 0.62 degrees. Using the positive feedback loops proposed by climate scientists this should be 1.25 to 3.72 degrees.
Okay, so how much actual warming had we observed since 1950? 0.50 degrees. This is actually indicates there are no multiplier effects occurring, at least no positive effects (there may even be a weak negative multiplier). Thinking a bit more about this – it seems unlikely that the earth, which has been around for a long time, and habitable by plants and animals, is dominated by a positive climate feedback. Systems dominated by positive feedback don’t tend to be very stable for long periods of time.
So based on just that simple math, I decided to stop worrying about climate change.
Monckton of Brenchley
April 24, 2018 3:36 pm
Geo’s reasoning is sound. Jouzel et al. (2007) found that, after allowing for polar amplification, global mean surface temperature has varied by only 3 degrees above or below the 810,000-year mean. That is a powerful indication that feedback is small.
Bellman
April 25, 2018 6:04 am
Geo,
“Okay, so how much actual warming had we observed since 1950? 0.50 degrees.”
Where do you get the 0.5°C warming since 1950. Monckton’s original article pointed out the rate of warming has been 1.2°C / century. Over 68 years that would mean 0.82°C warming.
“Carbon dioxide concentrations have increased since 1950 from 270 ppm to 400 ppm, or 130 ppm, which is a 48% of the first doubling.”
CO2 was not 270 ppm in 1950 it was 311. The rise in CO2 since 1950 has been more like 30%, or slightly less than 40% of a doubling when taking logarithms into account.
Bellman
April 25, 2018 8:17 am
This reminds me, I’m not sure if Monckton of Brenchley ever justified his Test 3 from the original article, where he claimed a rate of warming of 1.2°C / century since 1950 verified the sensitivity value of 1.2K.
Monckton of Brenchley
April 25, 2018 11:03 am
In response to Bellman, IPCC originally predicted warming at a rate of 3.3 K/century, and the CMIP5 models predict warming of 3.3 K in response to doubled CO2. Many other such examples could be cited.
Bellman
April 25, 2018 11:42 am
“In response to Bellman, IPCC originally predicted warming at a rate of 3.3 K/century…”
But that’s over the 21st century. CO2 did not double over the 20th century – it has only increased by ~ 30% in the 68 years since 1950. How could that lead to a warming rate equal to climate sensitivity over a century?
Monckton of Brenchley
April 26, 2018 3:31 am
In response to Bellman, IPCC predicted, on p. xxiv of the 1990 report, that there would be 1.8 K warming by 2030, compared with pre-industrial. From 1850-1990 there was 0.45 K warming. So IPCC was predicting warming over the medium term would be 1.35 K over four decades, or 3.3 K per century equivalent. The CMIP3 and CMIP5 models predict 3.3 K warming per CO2 doubling.
How does this approximate equivalence arise? CO2 is expected to reach about 620 ppmv in 2100 compared with the 368 ppmv in 2000: thus, the radiative forcing from CO2 this century will be 2.6 Watts per square meter. Increase this by 229/168, the ratio of net anthropogenic forcing from all sources to the forcing from CO2 up to 2011 (IPCC, 2013, Fig. SPM.5) and one gets 3.5 Watts per square meter, which is the current models’ estimate of the radiative forcing response to doubled CO2.
Bellman
April 26, 2018 5:38 am
In response to Bellman, IPCC predicted, on p. xxiv of the 1990 report, that there would be 1.8 K warming by 2030, compared with pre-industrial. From 1850-1990 there was 0.45 K warming. So IPCC was predicting warming over the medium term would be 1.35 K over four decades, or 3.3 K per century equivalent. The CMIP3 and CMIP5 models predict 3.3 K warming per CO2 doubling.
I’ll repeat what I’ve already said, the first IPCC report did not predict a medium term warming rate of 3.3 °C / century. You said only a couple of years ago that they predicted “2.8 [1.9, 4.2] C°/century” up to 2025.
You quote the CMIP3 and CMIP5 models predicting 3.3 K sensitivity, but as you’ve previously pointed out the second IPCC models predicted sensitivity of 3.8°C.
To me it seems like you are just plucking out any figure that can be used to get this coincidence of centennial warming rate and sensitivity.
How does this approximate equivalence arise? CO2 is expected to reach about 620 ppmv in 2100 compared with the 368 ppmv in 2000: thus, the radiative forcing from CO2 this century will be 2.6 Watts per square meter. Increase this by 229/168, the ratio of net anthropogenic forcing from all sources to the forcing from CO2 up to 2011 (IPCC, 2013, Fig. SPM.5) and one gets 3.5 Watts per square meter, which is the current models’ estimate of the radiative forcing response to doubled CO2.
I don’t have time at the moment to look at this in more detail, but as I understand it you are saying you need to increase any warming from CO2 increases by around 1.36 to allow for non-CO2 increased forcings. But the way you are doing it seems too simplistic to be realistic. Surely the ratio will change over time, and if you are right about halving the sensitivity, the ratio will have to increase.C.
Monckton of Brenchley
April 26, 2018 1:59 pm
In response to Bellman, the first IPCC report predicted 1 K warming by 2025, but it separately predicted 1.8 K by 2030, compared with pre-industrial. I provided Bellman with the reference: p. xxiv of IPCC (1990). Warming from pre-industrial to 1990 was 0.45 K: therefore, IPCC was predicting warming of 1.35 K over 40 years, or about 3.3 K as a centennial equivalent.
However, Bellman does not seem to appreciate that our result does not depend upon any empirical calculations. We performed those merely to make sure that our quite robust theoretically-derived result was reasonable. Our theoretically-derived result depends upon only three quantities upon which all or almost all are ready to agree: the emission temperature of 255 K, the warming from the presence of the non-condensing greenhouse gases, which is about 12 K, and the equilibrium temperature in 1850, before any significant anthropogenic perturbation, which was 287 K. From these three quite well constrained quantities, one can derive the feedback factor 1 – (255 + 12) / 287, or 0.07. That value, however, assumes that the feedback factor is constant, when it in fact rises near-linearly and rather slowly with temperature. Accordingly, one can try various higher values of the feedback factor. Even if, per impossibile, one imagined that the feedback factor was four times 0.07, the Charney sensitivity would be only 1.5 K.
The question of the approximate equivalence of the 21st-century anthropogenic forcing and the CO2 forcing is not, therefore, in any way essential to our argument. It is a convenient approximation and no more.
Bellman
April 27, 2018 7:47 am
“The question of the approximate equivalence of the 21st-century anthropogenic forcing and the CO2 forcing is not, therefore, in any way essential to our argument. It is a convenient approximation and no more.”
I find this argument contrasts with what you said in the original article and brief. There you said:
“They verified it by obtaining near-identical results via two empirical methods, and compared these results with the centennial-equivalent global warming rates measured from 1950-2017 and from 2001-2017.”
It’s difficult to reconcile “verified” and “near-identical” with “convenient approximation”.
Monckton of Brenchley
April 27, 2018 3:22 pm
It is very difficult trying to communicate uncertainties to non-scientists such as “Bellman”. As has been made repeatedly clear in this series, our argument depends crucially on the position before any appreciable anthropogenic influence was detectable. There, the relevant quantities – the emission temperature at today’s insolation and albedo, the warming caused by the presence of the non-condensing greenhouse gases, and the surface temperature at the 1850 equilibrium, are reasonably well established and generally agreed numbers. There is little uncertainty in them. From these, we can derive theoretically a definitive value 0.07 for the feedback factor, under the assumption that it is constant. It is not constant, so one might double it or even quadruple it to allow over-generously for the rate at which it might increase with temperature: but that still gives an equilibrium sensitivity of only 1.5 K at most.
We then verified this theoretically-obtained result by numerous empirical methods. These verifications were intended not as primary calculations of Charney sensitivity, for there are far too many uncertainties in the underlying quantities. We do not know how much net anthropogenic forcing there has been; we do not know how much global warming there has been; we do not know what fraction of global warming was anthropogenic; we do not know what the planetary imbalance is. All of these quantities are subject to wide error margins. The best we can do, therefore, is take mid-range estimates. And that is where the approximate equivalence of the 21st-century anthropogenic forcing and the CO2 forcing comes in. It is based on mid-range estimates, and it gives a respectable idea of what is going on.
And if Bellman cannot detect any similarity between “near-identical” and “approximation”, then let him take a course in elementary mathematics, with particular reference to the handling of uncertainties, error margins and confidence intervals.
Bellman
April 27, 2018 6:26 pm
Lord Monckton, you are correct I am not a scientist, but I do have experience in testing, and no the meaning of the word verification.
“These verifications were intended not as primary calculations of Charney sensitivity, for there are far too many uncertainties in the underlying quantities. We do not know how much net anthropogenic forcing there has been; we do not know how much global warming there has been; we do not know what fraction of global warming was anthropogenic; we do not know what the planetary imbalance is. All of these quantities are subject to wide error margins.”
Yet you used them to verify a theoretical sensitivity given to within 0.15°C. In your brief you said they all cohered in finding sensitivity to be between 1.2 and 1.3 K, and said there was an equivalence between sensitivity and a warming rate per century. Now you are saying there are too many uncertainties to know if the rate of change is equivalent to Charney sensitivity. This implies to me that any similarity between the rate of change over carefully selected time periods and your theoretical result could just be coincidence. How big a difference would you have to see before your test failed?
“And if Bellman cannot detect any similarity between “near-identical” and “approximation”, then let him take a course in elementary mathematics…”
Thanks for the advice, but I do have some elementary mathematical education, and I didn’t say there were no similarities in between the words, I said it was difficult to reconcile the concepts. However re-reading the relevant section it seems I owe you an apology. The word “near-identical” was not referring to the observational tests, but to two other empirical methods. The results from global temperatures were only described as cohering to the theoretical result.
Monckton of Brenchley
April 28, 2018 11:02 am
Bellman continues to have grave difficulty in elementary comprehension. Our derivation of the corrected feedback factor does not, repeat not, repeat not, repeat not depend upon empirical methods. It is a theoretical derivation, based on the known temperature equilibrium in 1850, before Man significantly perturbed the climate. The uncertainty in that derivation is very small.
The uncertainties in any empirical attempt to derive equilibrium sensitivities are far larger, for the reason i have explained. Yet, on the assumptions stated in the head postings, even the empirical uncertainty is small. Other assumptions might be adopted: see e.g. Lewis & Curry, 2018, who have managed to bring down the upper bound of Charney sensitivity from 9 K to 2.4 K. With us, even if one used absurdly extreme values, the upper bound is 1.5 K; but, on any realistic values, the upper bound is not much above 1.3 K.
Bellman
April 28, 2018 6:30 pm
“Bellman continues to have grave difficulty in elementary comprehension. Our derivation of the corrected feedback factor does not, repeat not, repeat not, repeat not depend upon empirical methods.”
Bellman completely understands that. That’s why Bellman repeated you claims that the empirical methods were being used for verification.
“It is a theoretical derivation, based on the known temperature equilibrium in 1850, before Man significantly perturbed the climate. The uncertainty in that derivation is very small. ”
Yet you said you thought the actual sensitivity was less than half of your theoretically derived value, that’s not a small uncertainty.
Monckton of Brenchley
April 29, 2018 5:38 am
Bellman continues to be ever more hopelessly confused. One hopes the confusion is not deliberate.
For the nth time, for the sake of argument we have adopted all of official climatology except what we can prove to be false. Therefore, for the sake of argument we have accepted, inter alia, that reference sensitivity is 1.1 K before taking any account of feedback, and that the net effect of feedbacks is to increase that sensitivity. Our best estimate of equilibrium sensitivity is 1.2 K, based on the feedback factor 0.07 we have derived from the temperature equilibrium in 1850 before any significant anthropogenic perturbation.
We have shown in the head posting that, if one makes allowance for the Earth’s energy imbalance, the implication of our result when applied to observed warming since 1850 is that about a quarter of that warming was natural. This conclusion is, of course, consistent with the supposed (but not real) “consensus” position that recent warming was mostly anthropogenic.
However, we have pushed the argument as far towards official climatology’ position as we can. We have borne in mind what would be the case if all of the warming since 1850 was anthropogenic. In that event, the implicit value of the feedback factor would be about 0.3, which would imply a Charney sensitivity of 1.55, not the 1.2 that we had earlier derived. With the best will in the world, one cannot plausibly allege, as the mathematically-challenged Bellman is trying to allege, that 1.55 K is twice 1.2 K.
Going in the other direction, it is possible to allow for the results of Happer (2015) and Harde (2015). Using different and non-overlapping methods, they determined that reference sensitivity had been overstated by 40% and 30% respectively, or 82% combined. In that event, reference sensitivity would be 1.1 / 1.82, or 0.6 K, and equilibrium sensitivity, for f = 0.07, would be 0.6 / (1 – 0.07), or 0.65 K.
However, we cannot prove that Happer and Harde are correct. Therefore, our best estimate is that Charney sensitivity, theoretically derived from the position at the pre-anthropogenic temperature equilibrium in 1850, is 1.2 K, and our empirical verification in the industrial era demonstrates that this result is consistent with the assumptions a) that global warming of 0.76 K occurred from 1850-2011; b) that there was 2.3 Watts per square meter net anthropogenic forcing over the same period; c) that there was a radiative imbalance of 0.6 Watts per square meter to 2010; and d) that three-quarters of the equilibrium warming from 1850-2011, after taking account of the energy imbalance, was anthropogenic.
Bellman
April 29, 2018 9:56 am
“With the best will in the world, one cannot plausibly allege, as the mathematically-challenged Bellman is trying to allege, that 1.55 K is twice 1.2 K.”
I was alluding to you previous statement that “I suspect that Charney sensitivity is not much above 0.5 K”, when I said that your 1.2 K figure could be out by a factor of 2.
Yes, you have said repeatedly that all you calculations are based on the assumption that everything you cannot prove to be false is true, but when you first introduced your new result you presented it with a high degree of confidence, 1.2 ± 0.15 K, and that this value was “verify by multiple empirical methods”.
Since then we’ve been going round in circles trying to decide if this value is true in the real world, or just a hypothetical figure based on what you cannot prove to be false. I would assume the former if you accept the “numerous” tests, all cohering to the same value. But then, when questioned about one of these tests you describe it as a “convenient approximation and no more”.
You claim at the start was that in order to refute 1.2 sensitivity value, people would have to demonstrate why the rate of warming since 1950 was irrelevant. Now you are arguing that it is irrelevant.
Bellman
April 30, 2018 4:06 am
Increase this by 229/168, the ratio of net anthropogenic forcing from all sources to the forcing from CO2 up to 2011 (IPCC, 2013, Fig. SPM.5)
I think there may be a mistake in that ratio. IPCC give forcing from emitted CO2 as 1.68, compared with all anthropogenic forcing of 2.29. But that doesn’t include CO2 produced from CH4 etc. The IPCC state that the forcing from all anthropogenic CO2 as 1.82. Therefore the ratio should be 229/182 = 1.26, and not 1.36.
Of course this ignores the huge uncertainties int he IPCC report. Total anthropogenic forcing go from [1.13 to 3.33], CO [1.46 to 2.18].
Monckton of Brenchley
April 30, 2018 5:47 am
Bellman is becoming more than a little tedious. I repeat that our result was obtained by theoretical means and then verified by empirical means. The theoretical result is subject to very few of the uncertainties that attend any attempt at empirical verification. It depends on the emission temperature 255 K, the 8-12 K contribution from non-condensing greenhouse gases and the equilibrium surface temperature of 287 K in 1850. The only uncertainty is in the rate of change of the feedback fraction with temperature: but even if one were to assume, absurdly, that the feedback fraction is four times the 0.07 we have derived theoretically, Charney sensitivity is still only 1.5 K, the value that is also derivable empirically if one assumes, per impossiblie, that all global warming since 1850 was manmade (see Lewis & Curry, 2018).
And if Bellman would like to imagine that the ratio of net anthropogenic forcing to the forcing from CO2 is smaller than we have thought, well, that is one of the many uncertainties attendant upon an empirical derivation of Charney sensitivity. However, using the published mid-range estimates and assuming that just one-quarter of the 1 K global warming since 1850 (including the contribution from the energy imbalance) was anthropogenic, the feedback fraction remains at 0.07 and the Charney sensitivity is 1.2 K.
The more that Bellman quibbles about whether Charney sensitivity is 1.2 K or 1.3 K or 1.5 K, the more he underlines the robustness of our result, which demonstrates that, even on the most extreme assumptions, it is hard to posit a Charney sensitivity above IPCC’s long-standing minimum estimate, once the calculation is corrected for the large error we have identified. If Charney sensitivity is anywhere in that ballpark, then that is the end of the climate scare, and no amount of quibbling will revive it.
Bellman
April 30, 2018 7:29 am
“I repeat that our result was obtained by theoretical means and then verified by empirical means.”
Yes, you keep repeating that, and I don’t know why as I’ve never denied that you obtained the result by theoretical means. I’m just trying to find out what you mean by “verified”.
“The theoretical result is subject to very few of the uncertainties that attend any attempt at empirical verification.”
Any model is subject to a huge range of uncertainties depending on the assumptions in that model. As evidence I repeat your assertion that the actual sensitivity might be only 0.5 K, far outside the declared theoretical uncertainty of 1.2±0.15 K.
“And if Bellman would like to imagine that the ratio of net anthropogenic forcing to the forcing from CO2 is smaller than we have thought, well, that is one of the many uncertainties attendant upon an empirical derivation of Charney sensitivity.”
We were talking about your claim that the rate of warming since 1950 of 1.2°C / century was agreeing with your sensitivity of 1.2 K. It seemed you were suggesting that the two values being the same verified the sensitivity value. You did this as far as I can see without any calculations, just the assumption that sensitivity was equivalent to a centennial warming rate.
But then you say, correctly, that there are many uncertainties in using empirical methods, so the question remains how much uncertainty is there in your verification? How big a difference between the trend since 1950 and the sensitivity would be required to fail the test?
“The more that Bellman quibbles about whether Charney sensitivity is 1.2 K or 1.3 K or 1.5 K, the more he underlines the robustness of our result,”
I’ve made no claims about the the actual value of sensitivity. I’ve been trying to determine what you think the sensitivity is. I’m not a scientist, I couldn’t argue if your claim of identifying an error in the IPCC calculations are correct or not, and I’m not suggesting 1.5K is an upper limit on any possible sensitivity value.
“it is hard to posit a Charney sensitivity above IPCC’s long-standing minimum estimate”
The IPCC’s minimum estimate is 1 K, but likely to be above 1.5 K. You’ve already posited a sensitivity of 1.6 K.
April 24, 2018 3:00 pm
How do the inanimate water vapor, albedo and other feedback processes in the climate know that they must respond little, if at all, to the 255 K emission temperature, but that they must suddenly respond with as much as 22-24 K of feedback-driven warming triggered by the extra 9-11 K of temperature directly forced by the presence of the non-condensing greenhouse gases?
How does an inanimate gram of ice know that it must raise its temperature from -10° C. to 0° C. in response to the first 25 J. of heat absorption but that it must suddenly resist any further temperature change at all in response to the next 25 J.?
How does an inanimate tunnel diode know that it must increase its current in response to the first 100 mV but that it mus suddenly decrease its current in response to the next 100 mV?
Some of the universe’s many mysteries.
Monckton of Brenchley
April 24, 2018 3:39 pm
Anyone familiar with applied control theory would realize that, in a circuit such as that depicted in the head posting, there is no way in which the feedback processes represented by the beta feedback fraction can decide not to respond to emission temperature of 255.4 K but then decide to respond aggressively to the next 12 K of temperature. Elementary control theory, as well as empirical verification on two test rigs, one of them at a government laboratory, shows that the feedback processes cannot draw any such artificial distinction.
April 24, 2018 7:27 pm
“there is no way in which the feedback processes represented by the beta feedback fraction can decide not to respond to emission temperature of 255.4 K but then decide to respond aggressively to the next 12 K of temperature”
It does not make sense to speak of feedback to an unchanging property. But if you insist, yes, there is a way. Because it has already responded to the 255.4 K long ago. Or if you insist it should respond again, then why only now? Why not again in a few minutes, then again etc. As said, it just makes no sense.
Alan Tomalty
April 24, 2018 11:53 pm
Well the initial date should be 4.6 billion years ago to satisfy Nick. Chris you should use the date of 4.6 billion years ago as your 1st feedback date.
Monckton of Brenchley
April 25, 2018 1:33 am
Mr Stokes says, “It does not make sense to speak of feedback to an unchanging property.” Welcome to the counter-intuitive mathematics of feedback. One of the reasons why official climatology’s error in not accounting properly (if at all) for the feedback response to emission temperature has gone unnoticed until now is that the mathematics is counterintuitive.
One way to look at it is simply to set the mu amplification to unity and run the equation represented by the diagram in the head posting, with an input value and a nonzero beta feedback fraction. The output value will differ from the input value.
Another way to look at it is to imagine that the emission temperature plus the additional temperature from the non-condensing greenhouse gases are both present, before accounting for feedback. Assume that in 1850 there was a radiative equilibrium (for our influence at that stage was very small). Now, was the temperature in 1850 255.4+12 = 267.4 K, or was it 287.5 K? It was, of course, the latter. And yet there had been no perturbation of the climate, which was in radiative equilibrium. Now, in that scenario, how can the feedback processes, such as water vapor, distinguish between the emission temperature and the additional 12 K from the presence of the non-condensers? Well, they can’t. They respond to both. So the feedback fraction is simply 1 – (255.4 +12) / 287.5, or 0.07, and not 1 – 12 / 32 = 0.63.
April 25, 2018 6:00 am
True, I can’t be absolutely sure about a “test rig” I haven’t seen. But my experience with guys similarly afraid to show their cards tells me this will prove to be vaporware. My guess is that the “test rig” will turn out to be nothing more than a straight linear feedback circuit whose mu and beta are simply set with potentiometers, i.e., do not depend, as the chimerical head-post circuit does, on the input and output voltages.
Monckton of Brenchley
April 25, 2018 11:07 am
The Born [politely pruned] resorts to mere spite, again. Since he has absolutely zero knowledge of elementary control theory, let me explain that the circuit illustrated in the diagram in the head posting does not require the mu direct-gain factor to be dependent upon the input signal, any more than the directly-forced warming from the presence of the naturally-occurring, non-condensing greenhouse gases is dependent upon the emission temperature. Likewise, the feedback fraction can be set separately.
April 26, 2018 6:08 am
he has absolutely zero knowledge of elementary control theory
This is rich coming from someone who repeatedly and intransigently makes the most-fundamental of errors in that discipline.
The central equation of his “Irreducibly Simple Climate Model” paper perpetrated the howler that a linear system’s response is well approximated by merely multiplying the stimulus by the system’s step response. To control-systems types, that’s like saying you can get two operands’ product by adding them: it occasionally works, but you’d be a fool to count on it.
Despite my having demonstrated otherwise, Lord Monckton for years insisted that feedback theory consisted of “rogue equations” inapplicable to climate. He only recently (but tacitly) repented of that position. That’s progress, I suppose, but he does seem to be a slow learner.
Even though he has repented, it appears that he still misinterprets the gain-versus-feedback-factor hyperbola, now thinking it indicates that $f>1$ implies global cooling. It doesn’t. In connection with Figs. 12 and 13 of the post at https://wattsupwiththat.com/2015/03/12/reflections-on-monckton-et-al-s-transience-fraction/, moreover, I years ago instructed him that the corresponding behavior is not true of the electrical analog, either.
Now, it’s true that I’m no controls-systems expert. However, I did make it my business several decades ago to study the subject in depth; for clients I familiarized myself with control systems vastly more complicated than the rudimentary arrangements that Lord Monckton is struggling unsuccessfully to treat here. On one occasion I saved a client from a seriously bad investment by pointing out a control-systems mistake made by a PhD at one of my country’s premiere science institutions. So, no, I can’t say I’m an expert. But this isn’t my first rodeo, either.
April 26, 2018 6:56 am
[T]he diagram in the head posting does not require the mu direct-gain factor to be dependent upon the input signal. . . . Likewise, the feedback fraction can be set separately.
Note that Lord Monckton has not denied how trivial his “test rig” is. Note also that his use of the word input shows how far his weird contortions such as the head-post equations have taken him from the question at hand.
He claims he’s “proven that the large estimates of the feedback factor arise from an elementary error of physics,” namely, that climatologists have “made the grave error of not realizing that emission temperature $T_E$ (= 255 K) itself induces a substantial feedback.” Their models’ small-signal behavior is said to match a feedback relationship $\Delta T=\lambda_0(\Delta F+k\Delta T)$. Here the input is obviously the forcing perturbation $\Delta F$, and algebraically isolating the output $\Delta T$ results in $\Delta T=\frac{\lambda_0}{1-\lambda_0k}\Delta F$.
Lord Monckton has hopelessly obscured the issue and apparently confused himself in the process by (1) opaquely transforming the input forcing perturbation $\Delta F$ into a temperature change $\Delta T_{\mathrm{ref}}$ and (2) not applying that input properly to the summing junction but instead using it to control the value of the ostensible open-loop gain $\mu$. Specifically, he assigns that parameter the value $1+\frac{\Delta T_{\mathrm{ref}}}{T_{\mathrm{ref}}}$. So, contrary to Lord Monckton’s contention, $\mu$ depends on the input $\Delta T_{\mathrm{ref}}$.
Of course, if you (not unreasonably) look at the input as the whole quantity $T_{\mathrm{in}}\equiv T_{\mathrm{ref}}+\Delta T_{\mathrm{ref}}$ in which the small-signal input $\Delta T_{\mathrm{ref}}$ is a perturbation, then the actual open-loop gain is unity ($T_\mathrm{eq}=\mu T_{\mathrm{ref}}=(1+\Delta T_{\mathrm{ref}}/T_{\mathrm{ref}})T_{\mathrm{ref}}=T_{\mathrm{ref}}+\Delta T_{\mathrm{ref}}=T_{\mathrm{in}}$), independently of $\Delta T_{\mathrm{ref}}$. But there remains the fact that setting the feedback fraction $\beta$ “separately” would mean that the closed-loop gain $\dfrac{1}{1-\beta T_{\mathrm{in}}/T_{\mathrm{ref}}}$ depends on the input $T_{\mathrm{in}}$.
He can contend the circuit “does not require the mu direct-gain factor to be dependent upon the input signal.” only by taking $T_{\mathrm{ref}}$ by itself as the input and taking the true small-signal input $\Delta F$ (somehow transformed to $\Delta T_{\mathrm{ref}}$) as a parameter. And probably that is all his “test rig” does, in which case it proves nothing of consequence.
Lord Monckton continues incoherently to conflate small-signal with large-signal, input with parameter, linear with non-linear. What a mess.
Monckton of Brenchley
April 26, 2018 11:54 am
If only Mr Born would look at this matter dispassionately and in the pursuit of objective truth, he would not continue to make elementary errors of arithmetic and of control theory, of which he has remarkably little knowledge.
He makes the remarkably bonkers assertion that, where the emission temperature is Te, and the mu direct-gain factor is 1 + delta-Te / Te, the gain factor is dependent upon Te. Of course it isn’t. Suppose that the directly-forced warming delta-Te from the presence of the naturally-occurring, non-condensing greenhouse gases is, say, 12 K. Suppose that the emission temperature is 255 K. Then the direct-gain factor is 1 + 12 / 255 = 1.0471. Suppose, on the other hand, that Lacis 2010 is right to imply it is 9 K. then the direct-gain factor is 1 + 9 / 255 = 1.035. Yet the emission temperature Te is the same in both cases.
Mr Born continues to correspond here in his habitually spiteful, sneering tone. He should recall that sneering at me won’t make the slightest difference. Everyone can tell from his tone that he is not a seeker after truth but a partisan. Our research team does not consist of only me. There is a professor of control theory, who considers that the description of the feedback loop that I have given is correct.
Since Mr Born appears to think that personalities, rather than science, are important, then he should know that a professor of control theory is more likely to be heeded than Mr Born. He is entitled to his opinion, but it is the opinion of a retired lawyer, whereas our opinion is the opinion of, inter alios, not one but three control theorists, supported by an independent external reviewer who is both a control theorist and a climatologist.
April 26, 2018 12:22 pm
[O}ur opinion is the opinion of, inter alios, not one but three control theorists, supported by an independent external reviewer who is both a control theorist and a climatologist
Yet not one of has shown up here, given his identity, affiliation, and credentials, and staked his reputation on backing up in his own words the silly things Lord Monckton says. Let Lord Monckton bring them on. Let’s see how they stand up. If they’re what Lord Monckton says, they should have no trouble with a retired lawyer.
As I say, though, this isn’t my first rodeo. And to me Lord Monckton looks like all hat and no cattle.
Monckton of Brenchley
April 27, 2018 6:41 am
As usual, the Born Liar cannot resist being petty, and, as usual, fails to advance anything recognizable as a credible scientific point.
He says none of my co-authors has “shown up here, given his identity, affiliation, and credentials, and staked his reputation on backing up in his own words the silly things Lord Monckton says.” O, how ineffably childish is the Born Liar’s spite. My co-authors have neither the time nor the inclination to subject themselves to the pathetic hatred and snide comments of the totalitarian true-believers such as the Born Liar, whose every comment here betrays his utter lack of interest in the objective truth.
My distinguished co-authors have lent their name and their expertise to our draft paper, which, we hope, will in due course pass successfully through peer review. That is their role, and it is an appropriate one for practising scientists. Why should they waste their time dealing with confused, half-recalled drivel from a clapped-out shyster?
The process of peer review will not be a rapid process, for our result – if correct – is a mortal blow to official climatology and to all who, like the Born Liar, prefer to imagine that The Science Is Settled and The Debate Is Over and Now We Must Act. We are expecting a degree of scrutiny a great deal more rigorous, and a great deal tougher, and a great deal more intellectually honest, than the generally feeble points that have been made by the hate generation here. My co-authors are rightly conserving their strength for dealing with the reviewers, and they see no reason to endure the hate speech that is the common currency of the totalitarian supporters of the Party Line on climate, such as the Born Liar.
April 27, 2018 4:04 pm
My co-authors have neither the time nor the inclination to subject themselves to the pathetic hatred and snide comments of the totalitarian true-believers such as the Born Liar
Translation: They’re all third-raters afraid to go on record to dispute what a superannuated lawyer specified in explicit math for all to see. Got it.
Monckton of Brenchley
April 28, 2018 10:58 am
The Born Liar again betrays his ignorance of the scientific method and his totalitarian proclivity in sneering at my co-authors. No doubt he, as a threadbare shyster of no particular distinction, considers his wisdom on scientific questions vastly superior to theirs, because he adheres to the Party Line and they, in the respect we have identified, do not. Few here would agree with him. His malice, his prejudice, his spite and his wilful disregard of objective truth are visible to all.
Our result is simple. Official climatology has overegged the pudding, climate-sensitivity-wise. Warming in response to doubled CO2 will not be 3.3 K or 4.5 K or 10 K or 11 K: it will be not much above 1 K. Get over it, and enjoy the sunshine.
April 24, 2018 3:28 pm
Rule of Chinese martial arts: leave your opponents only one graceful way out.
Give them that and we can have our economies back now.
Monckton of Brenchley
April 24, 2018 3:40 pm
Ladylifegrows makes a very fair point. How would she construct a rat-hole for the Forces of Darkness to scurry away? It’s not easy, because They have nailed Their totalitarian colors to the mast of the sinking ship global warming.
WXcycles
April 25, 2018 7:23 am
Build a time machine, then send all alarmism fans to the Carboniferous to confront their carbonphobia delusions. It would do them good to see the Earth at its most healthy and productive ever, with huge seasonless wet forrests, all produced by high CO2 and humidity. Which said giant trees and micro plants produced the highest oxygen levels in all of geological history (~35%). Which made for gigantic lively animals with many teeth and stings. Which would also do them a lot of good.
4 Eyes
April 24, 2018 3:51 pm
May I suggest MoB that you make sure you have a rock solid team of well qualified helpers and energetic supporters backing you up. I suspect you will have to endure some very serious reactions from the new deniers given the stakes. You’ve prompted me to brush up on auto control theory which I haven’t revisited from over 40 years ago – I wish I’d paid more attention in lectures!
Monckton of Brenchley
April 24, 2018 5:29 pm
In response to 4-Eyes, my co-authors are Dr Willie Soon, an award-winning astrophysicist at the Harvard-Smithsonian Center for Astrophysics; Dr David Legates, Professor of Climatology at the University of Delaware; Dr Matt Briggs, Professor Emeritus of statistics at Cornell University; Professor Dietrich Jeschke, an associate professor of applied control theory in the Flensburg University of Applied Sciences; Dipl.-Ing. Michael Limburg, an electronics engineer; Mr John Whitfield, an electronics engineer (who built our in-house test rig); Mr Alex Henney, an expert in the electricity supply industry; and Mr James Morrison, who was recently able to forewarn a California senator of his acquaintance that an unusually strong atmospheric river was about to hit the State. His warning was several days ahead of any official warning.
These, then, are a powerful team of experts in all the relevant fields. I am proud to be working with them. And it is owing to their patience and determination that we have achieved what we have achieved so far.
richard
April 25, 2018 1:13 am
If only all your work had been filmed for a documentary. It would have been interesting seeing all this thrashed out.
Monckton of Brenchley
April 25, 2018 11:08 am
In response to Richard, I suspect the proposed documentary would be rather dull, consisting of a series of emails over several years, together with meetings at scientific conferences in various parts of the world. It would not be an exciting watch. But the end product, if we are right, will have been worth the wait.
April 24, 2018 4:24 pm
I still do not accept the very basic idea that an atmosphere causes Earth to be “warmer than it would otherwise be”.
I am under the impression that the day side of an Earth with no atmosphere would be ABOVE boiling by over 20 degrees Celsius, and the night side of an Earth with no atmosphere would be BELOW freezing by well over 100 degrees Celsius. Yes, if we want to obliterate this reality with a ridiculous “average”, the Earth would have a temperature lower than a TOTALLY DIFFERENT derived ATMOSPHERIC TEMPERATURE, but to say that the atmosphere warms the surface “on average” is ridiculous. The atmosphere REGULATES temperature within a habitable range.
Using this temperature difference between a theoretical black-body temperature derived by ideal calculation, and then comparing it to a measured-and-statistically contrived average ATMOSPHERIC temperature seems, not only confused, but ignorant of day and night.
Monckton of Brenchley
April 24, 2018 4:41 pm
Mr Kernodle’s dispute is not with me but with official climatology. The approach we have taken is to accept ad argumentum all of official climatology except what we can prove to be false. We can prove that official climatology’s feedback factor 0.7 is an order of magnitude too big.
And the head posting makes it plain that we are not necessarily content with official climatology’s estimate of the emission temperature that would obtain in the absence of the non-condensing greenhouse gases. We have, however, accepted it for the sake of argument. Mr Kernodle should express his concerns about official climatology to [email protected].
Chimp
April 24, 2018 4:43 pm
IMO it’s fair to say that the net effect of having an atmosphere is to warm Earth, since air warms the night side more than it cools the sunny side. But it works in tandem with the oceans, and a bit with the land.
HotScot
April 24, 2018 5:02 pm
Chimp
I’m so thick, I never thought of that before. Every day’s a school-day at WUWT.
Thank you. Genuinely.
Chimp
April 24, 2018 5:07 pm
You’re welcome, although I’m not absolutely sure I’m right.
April 24, 2018 4:52 pm
@ Christopher Monckton – I hope I didn’t miss this point in the articles you’ve posted here, but what I’m wondering is if you are taking account of the low amounts of water vapor in very cold atmospheres. I expect that at cold temperatures, almost all the water vapor freezes out. It is said that the water vapor feedback is non-linear, but I would guess that an even stronger statement might be true, that at low temperatures, the water vapor feedback is zero or so close to zero as to be effectively zero. So how much water vapor is expected to be in air at 255K, which is 18 degrees Celsius below freezing or -1degF? And how much temperature rise would be expected due to just the feedbacks to the emission temperature of 255K, i.e. not including CO2 etc? If no significant water evaporates at that temperature then I would expect no significant feedback.
On the other hand, I’m with you in that it is perplexing to me that others don’t think they should take into account as a feedback, whatever warming does occur from the water vaporized by that 255K (or other effects like ice albedo or clouds). Sure, they can pick an oddly narrow definition of “feedback”, but it seems that they should still have to include the effects in their equations, whether they are called feedbacks or not. Maybe you should end the debate about whether they are feedbacks by just coming up with a new name for them, like Emission Temp Boost Effects, and then challenge them to justify why they should leave the ETBEs out of their equations if they do.
Also, how does one get an average radiation surface temperature like 255K? The equator would surely be warmer than the poles, and the radiation is related to the fourth power of the temperature, so does one take a weighted average of the polar, equatorial, and night side temperatures or something? You would even have to take account of the temperatures changing through the day and night as the surface heats and cools. That seems like a tricky calculation. It also seems like it would be tough to estimate the albedo with much accuracy, not knowing an accurate distribution of surface ice.
Monckton of Brenchley
April 24, 2018 5:41 pm
Mr Day raises a most intelligent and interesting question about whether there would be much in the way of water-vapor feedback at an emission temperature of 255 K. The first point to make is that, since there are non-condensing greenhouse gases in the atmosphere, the temperature to which the feedback processes such as the water vapor feedback respond is actually 255.4 + 12 = 267.4 K, which means that the tropics, which are the real engine-room of the climate, would be ice-free and the water-vapor feedback would be quite powerful, though not quite as powerful as today.
Mr Day’s point about the attempts by some commenters here to pretend that feedbacks won’t respond to 255 K of emission temperature but will respond to the additional 12 K of temperature forced by the presence of the non-condensing greenhouse gases is well made. One could give the feedback response to emission temperature a different name: but it is a feedback response, and I prefer to call things what they are rather than introducing any additional confusion into what is already the counter-intuitive subject of feedback theory. Besides, those here who are trying to say that feedbacks can somehow tell the difference between emission temperature and the amplification of it caused by the presence of the naturally-occurring greenhouse gases know perfectly well that feedback processes can make no such distinction. Because feedbacks increase near-linearly with temperature, there will be a little more feedback response pro rata to the temperature caused by the presence of the non-condensing greenhouse gases than to the emission temperature, but not much.
In answer to Mr Day’s third point, the mean surface emission temperature of 255 K in the absence of any greenhouse gases or feedbacks is, in effect, a function of only two quantities: the insolation and the albedo. It can be calculated using the fundamental equation of radiative transfer. However, I have my doubts about doing such a calculation, because one should really do the calculation individually for each latitude and then integrate. Doing that, one finds that the temperature on the dayside of the planet in the absence of the non-condensing greenhouse gases is 288.9 K. The situation is more complicated on the nightside, because one must take into account the formidable heat capacity of the ocean and the limited rate of heat loss from the ocean at night. Merlis et al. (2010) attempted to do this for an Earthlike aqsuaplanet with albedo 0.38, considerably higher than today’s 0.29, and they still found that on the nightside the temperature was 250 K. Taking the mean of 288.9 and 250 K gives a global emission temperature of 269.5 K. We are not yet in a position to prove that result, owing to uncertainties as to the leakage of temperature from the dayside to the nightside and as to the overall nightside temperature, so for the time being we are using the 255.4 K value that appears all through the literature of official climatology.
joe
April 24, 2018 5:55 pm
we can blindly say the CO2 is the driver and water vapor is a feedback effect, as an argument can be made that water vapor has the stronger effect, and that warming from water vapor based greenhouse effect causes CO2 to rise, hence CO2 is the feedback. Could it be argued that water vapor and CO2 are coupled? I have seen no evidence the water vapor is constant unless driven by CO2 driven warming, as opposed to other warming sources.
ThinkingScientist
April 25, 2018 6:52 am
This question of the average emission temperature of the planet with no atmosphere intrigues me very much and I don’t think the average value of 255 K can be correct. Even without an ocean, the rockwould retain heat when the sub is not shining – there will be inertia. The obvious place to test such a calculation is the moon. I think it does require an integration with latitude and I have found a published dataset with the necessary temperature profiles with latitude and time of day. Unfortunately I am having to digitise them, its nearly done, but then I will be able to perform that integration and see what number comes out for the moon. Of course, rotational speed plays a role, but it will be an interesting exercise nonetheless.
Monckton of Brenchley
April 25, 2018 11:11 am
Thinkingscientist will find, when he has completed his lunar experiment, that the actual lunar mean surface temperature is very considerably below the 271 K that use of the fundamental equation of radiative transfer on a global scale would lead us to expect, given the lunar Bond albedo of 0.11.
On Earth, however, the position is the other way about owing to the formidable heat capacity of the ocean, which prevents loss of significant accumulated heat on the nightside. On the dayside, the temperature would be about 288.9 K on Earth, based on integration of latitudinal values; on the nightside, probably not less than 250 K. The true emission temperature of the Earth, then, is probably around 269.5 K.
joe
April 24, 2018 5:06 pm
I believe Prof. Lindzen made another argument why the runaway strong feedback amplification of CO2 induced warming is total rubbish. The feedback mechanism proposed does not operate on global average temperature with a response time scale of months or years, which is relatively stable, but rather on a regional scale with a response time of weeks if not days. In other words, any source of temperate rise on a regional scale over a period of weeks will induce a strong feedback. Yet temperature does have strong rises in these conditions without any run away effects. This cannot be averaged out with low temperatures elsewhere because the response is nonlinear, hence low temperatures has little feedback which high temperatures have strong feedback amplification.
Chimp
April 24, 2018 5:15 pm
Yes, and the Arctic is supposedly where the effect of CO2 is most pronounced, yet it hasn’t warmed enough there greatly to increase water vapor in the cold, dry air, especially of winter.
H2O varies enormously geographically, from at most a few molecules per million air molecules over Antarctica, to 40,000 per million in the hot, moist tropics. There has been no warming at the South Pole.
Monckton of Brenchley
April 24, 2018 5:49 pm
In response to Joe, there is indeed no basis whatsoever for assuming that a runaway feedback can occur, particularly if the feedback fraction is, as we have proven it to be, one-tenth of the official estimates. The feedback processes relevant to the climate are indeed quite quick-acting. IPCC itself now admits that the timescale for operation of the water-vapor feedback is hours, not days, months, years, decades or centuries.
Also, though the rate of change in specific humidity or column water vapor with temperature is exponential at 6 to 7% per Kelvin, the absorption occurs only at the far wings of the spectrum (as with CO2), so that the net absorption response is logarithmic, making the water vapor feedback increase linearly, and very slowly, with temperature. The Planck “feedback” also has a linear increase with temperature (a very small increase). The other feedbacks are too small to make very much difference. So our result, a feedback fraction of just 0.07, is actually plausible. Official climatology has only chosen larger values for the feedback fraction because its grave error of physics has led it to assume that it must somehow account for the 20 K of feedback response to the 12 K directly-forced warming from the non-condensing greenhouse gases. In fact, 19 K of this 20 K of feedback response is a response to emission temperature, and less than 1 K is a response to the 12 K of warming from the non-condensers.
joe
April 25, 2018 5:56 am
So, the IPCC makes assumptions that support their interpretation, only retracting when confronted with evidence? which was their job to find in the first place?
Monckton of Brenchley
April 25, 2018 4:15 pm
In response to Joe, IPCC does not always retract, even when confronted by evidence of its errors. The Swiss Bureau de l’Escroquerie is building up quite a file on it and, were it not for the fact that IPCC is worth billions a year to the Swiss economy, it would have been shut down years ago.
Juan
April 24, 2018 5:52 pm
We have had periods in history with 3-4x higher CO2 levels than today. If the high-sensitivity approach of IPCC is correct, I just cannot figure out how humans or animals would have been able to evolve or survive because the warming would have increased to a level where most of the living creatures cannot exist.
Chimp
April 24, 2018 6:03 pm
It appears that during the Cambrian Period, first of the Paleozoic Era and ongoing Phanerozoic Eon, CO2 has been estimated at ~7000 ppm, vs. ~400 ppm today. That’s more than four doublings of CO2, and, guess what!, global average temperature wasn’t more than 13 degrees C higher than now (as would be the case at IPCC’s ludicrous central value of 3.3 degrees C per doubling). Granted, the sun was about five percent weaker then, but still, observations don’t compute with “theory”. I wouldn’t dignify the CACA hypothesis with such a grand term, however.
During the following Ordovician Period, CO2 was still more than 11 times higher than now, but there was an ice age! Even average temperature during the period was only about two degrees C higher than now, despite 3.5 doublings.
willhaas
April 24, 2018 6:24 pm
The AGW conjecture is notorious for being based on only partial science. The improper feedback calculation is only one problem.
The radiametric calculations that I am familiar with come up with a climate sensitivity for CO2 of 1.2 degrees C which in itself tells us that the climate effects of adding CO2 to the atmosphere are not very significant. To make it more significant the AGW conjecture adds the concept of amplification by means of H2O feedback. The idea is that CO2 based warming causes more H2O to enter the atmosphere which causes more warming because H2O is also a so called greenhouse gas with LWIR absorption bands. They like to assume a positive feedback that results in an amplification factor of roughly 3 but admittedly they do not know exactly what that amplification factor really is. The idea is that CO2 based warming causes more H2O to enter the atmosphere which causes even more warming because H2O is also a greenhouse gas. In fact if you believe in the radiant greenhouse effect, H2O is the primary greenhouse gas and molecule per molecule, H2O is a stronger absorber of IR than is CO2. Christopher Monckton of Brenchly is apparently saying that, given that one accepts the “Official Climatology”, the amplification calculation is in error and must be significantly reduced. In the IPCC’s first report, they published a very wide range of possible values for the climate sensitivity of CO2. In the last report that I read of their’s they published the exact same values. So after more than two decades of effort they still do not really know what the amplification factor really is, they do not really know what the climate sensitivity of CO2 really is, and they have been unable to narrow the range of their guesses one iota. So’ in all that time they have learned nothing which would more accurately determine what the climate related danger of adding CO2 to the atmosphere really is. The climate simulation models supported by the IPCC have all predicted much more warming than has actually taken place which would lend credence to the idea that the lower feedback amplification feedback factor that Christopher Monckton of Brenchley has calculated is a much better number than what the IPCC has been using.
A researcher from Japan has pointed out that the radiometric calculations that were made totally ignore the fact that a doubling of CO2 will cause a slight drop in the dry lapse rate in the troposphere which is a cooling effect. When one includes this cooling effect, the climate sensitivity of CO2 is reduced by a factor of more than 20, So instead of 1.2 degrees C we have less than .06 degrees C for the climate sensitivity of CO2.
The AGW conjecture ignores the fact that besides being the primary greenhouse gas, CO2 is a major coolant in the Earth’s atmosphere, moving heat energy from the Earth’s surface to where clouds form where the energy is more readily radiated out to space. The over all cooling effect of H2O is evidenced by fact that the wet lapse rate is significantly less than the dry lapse rate. This means that the H2O feedback is negative and would operate to reduce any warming caused by CO2 How much H2O reduces the climate sensitivity of CO2 has not been determined by me but a climate sensitivity of less than .06 degrees C is already trivial. Negative feedback systems are inherently stable as has been the Earth’s climate for more than the past 500 million years..
A real greenhouse does not stay warm because of the action of heat trapping gases with LWIR absorption bands. A real greenhouse stays warm because the glass reduces cooling by convection. It is a convective greenhouse effect. So to on earth. The surface of the Earth is not kept warm because of the action of some trace gases with LWIR absorption bands. The surface of the Earth is as warm as it is because gravity limits cooling by convection. In the troposphere, heat energy transfer by conduction, convection, and phase change dominate over heat transfer by LWIR absorption band radiation. It is a convective effect that is a function of the heat capacity of the atmosphere, the pressure gradient, and the depth oft the troposphere that causes the insulation effects of the Earth’s atmosphere. All gases in the atmosphere play a part and no gasses in the Earth’s atmosphere are thermally inert as the AGW conjecture would have us believe. As derived from first principals the Earth’s convective greenhouse effect results in an average temperature at the Earth’s surface of 33 degrees C higher than it would otherwise be. 33 degrees C is the derived amount and 33 degrees C is what has been observed. Additional warming caused by a radiant greenhouse effect has not been observed in a real greenhouse, on Earth, or anywhere else in the solar system for that matter, The radiant greenhouse effect is science fiction so hence the AGW conjecture is science fiction.
If CO2 really affected climate by causing warming then one would expect that the increase in CO2 over the past 30 years would have caused at least a measurable increase in the dry lapse rate in the troposphere but that has not happened. There is no real evidence in the paleoclimate record that CO2 has any effect on climate. There is evidence that warming causes more H2O to enter the atmosphere as it is well known that warm water cannot hold as much CO2 as cooler water but there is no real evidence the added CO2 has caused any warming. It iis all conjecture.
My conclusion has been that there is not real evidence that CO2 has any effect on climate and plenty of scientific rational to support the idea that the climate sensitivity is essentially zero.
Dan DaSilva
April 25, 2018 1:30 am
What do you think is causing the warming, if not CO2?
willhaas
April 25, 2018 1:57 am
The sun and the oceans.
Monckton of Brenchley
April 25, 2018 1:57 am
In reply to Will Haas, experiments in the laboratory show that introducing CO2 to an atmosphere without it will intercept some of the near-infrared radiation passing through it, causing it to warm. The quantum physics of how a molecule of a greenhouse gas causes warming is quite well understood. The question, therefore, is not whether CO2 or other greenhouse gases cause warming, but how much warming they cause. Our answer is that they cause very little warming, because the feedback response, which official climatology had thought was large, is actually small. And we have proven that the large estimates of the feedback factor arise from an elementary error of physics, Correct that error and the global warming problem vanishes.
willhaas
April 25, 2018 9:32 am
I really appreciate your taking the time to respond to so many of our comments. That is a fundamental problem with climate science in that one cannot set up definitive experiments with the Earth’s climate system. One may be able to show that in the laboratory, adding CO2 to a volume of air may cause that block of air to warm more quickly when irradiated with LWIR radiation than that same block of air without the CO2 added to it, but that block of air in the laboratory is not the same as the Earth’s climate system. In the past it was believed that a greenhouse was kept warm because the glass blocked the passage of IR radiation but experiments were performed and showed that blocking the passage of IR radiation had nothing to do with it. I believe that you are right in that the feedback effects have been miscalculated but, as I have explained, there is a lot more wrong with the AGW conjecture then just the calculation of feedbacks.
Monckton of Brenchley
April 26, 2018 3:20 am
In response to Mr Haas, indeed there is a lot more wrong with official climatology than its definition of feedback. However, since feedbacks contribute two-thirds to nine-tenths of all imagined anthropogenic warming, correcting the definition of feedback removes almost two-thirds to nine-tenths of the imagined warming, leaving equilibrium sensitivity at not much more than 1.2 K.
Dan DaSilva
April 25, 2018 2:05 am
“A researcher from Japan has pointed out that the radiometric calculations that were made totally ignore the fact that a doubling of CO2 will cause a slight drop in the dry lapse rate in the troposphere which is a cooling effect”.
Could provide link or name of the researcher?
willhaas
April 25, 2018 9:57 am
Look at the Hockey Schtick.com Wednesday, November 11, 2015
Basic Global Warming Hypothesis is Wrong
by Kyoji Kimoto.
ScottM
April 26, 2018 1:38 pm
“The improper feedback calculation is only one problem.” If you consider that feedback isn’t a parameter that is dialed in arbitrarily, but emerges from the actual system itself (or in simulations thereof) due to the underlying physics, you’ll begin to see that this statement is nonsense. There isn’t a “feedback calculation” coded in climate models (except in extremely simple ones such as Monckton is using).
willhaas
April 26, 2018 4:18 pm
I believe that feedback is used to compute the climate sensitivity of CO2 and the warming that they think that adding CO2 to the atmosphere causes is hard coded into their simulations. The IPCC has published a wide range of guesses as to the climate sensitivity of CO2 and largely due to the uncertainty of the climate sensitivity of CO2 they have sponsored a plethora of climate models, really simulations. All of their models have failed to adequately predict today’s global temperatures. They have predicted global warming that has not happened. If there is any truth to the climate simulations, then one can conclude that the IPCC’s entire range of guesses as to the climate sensitivity is all wrong and that the actual is lower than the IPCC’s published range of guesses. For me a climate sensitivity of less than .06 degrees C is more defensible than anything the IPCC has published. Of course if one concludes that the climate sensitivity of CO2 is actually less than .06 degrees C then one must conclude that the climate effects of adding CO2 to the atmosphere by the burning of fossil fuels is negligible and hence the IPCC no longer needs to be funded.
Monckton of Brenchley
April 27, 2018 6:32 am
Will Haas’ point is interesting. Some years ago a specialist in forecasting techniques calculated that if one had predicted zero global warming in 1990 one would have been considerably closer to the truth than IPCC’s prediction at that time. Our result explains why IPCC has been over-predicting: it is using far too large a feedback factor.
Bob K
April 24, 2018 6:31 pm
The first picture is the building of the Ministry of Propaganda, 1934-1938, Hitler’s Germany. Found here: https://jaywaytravel.com/blog/berlin-nazi-architecture/
ggm
April 24, 2018 8:01 pm
Wrong. It isn’t the building in Germany. Just do a google for “Detlev-Rohwedder-Haus” and go to the Google Maps street view of the building, and you will see that this is definitely not the German building. Similar, but definitely not the same building
April 24, 2018 8:14 pm
It’s a view from the inside of the South-East quadrangle, not from the street.
Check the relative heights of the left and right rooflines.
John Hardy
April 24, 2018 10:53 pm
April 24, 2018 6:31 pm
“Did official climatology know its predictions were nonsense?”
A pertinent question but the most irrelevant question at the same time.
A better question, “Does official climatology care that its predictions were nonsense?”
knr
April 25, 2018 2:03 am
no because this brings in their ‘daily bread ‘ and where else could third rate academics get such an easy life.
Kristi Silber
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https://chemistryhelpforum.com/threads/phase-equilibria-physical-chemistry.147151/
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# Phase equilibria, Physical Chemistry
#### Sayantan
Aug 2019
3
0
Kolkata
The transition
Sn(s, gray) ⇌ Sn(s, white)
is in equilibrium at 18 °C and 1 atm pressure. If ∆S = 8.8 11K mol for the transition at 18 °C
and if the densities are 5.75 g/cm3 for gray tin and 7.28 g/cm3 for white tin, calculate the transi-
tion temperature under 100 atm pressure .
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http://perfectpuddle.blogspot.com/2015/11/kias-cfhep-workshop-liveblog-day-five.html
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## Friday, 13 November 2015
### KIAS-CFHEP Workshop Liveblog: Day Five Session Two
The last day of the conference, and the day after the banquet. As seems to be traditional, I overslept and missed the first session. Oh well. I missed two ILC talks that would probably have been interesting, but so be it.
11:20 am: Physics at a 100-TeV Collider, Tao Han
I'm guessing this talk will be similar to the seminar I saw Tao give recently.
HEP is at an extremely exciting time. The completion of the SM means that for the first time we have a complete and consistent relativistic quantum theory. Indeed, our theory seems valid up to the Planck scale (possibly). But we've thought this kind of thing before (19th century).
Indeed, the central questions today are not about details, but fundamental: origin of spacetime, UV/IR connection, real underlying theory. In this line, let us consider three questions.
1. The Nature of EWSB? All we really know is the Higgs potential in a tiny region about the vacuum. What does the full potential really look like? The first and most important question here is the nature of the Higgs triple coupling. This can consistently vary by order-1 factors relative to the SM! This would have huge effects on the cosmology, by allowing a 1st-order phase transition.
2. Naturalness. Possible theoretically nice explanations: true naturalness and NP at the TeV scale; a fundamental and deep connection between UV and IR physics; some kind of multiverse/anthropic selection effect.
3. Dark Sector. In particular, Higgs portal will be probed in the next generation of detectors. Additionally, these can be probed using measurements of Higgs physics at colliders.
The immediate collider future is, of course, the LHC. Looking further, and ignoring linear colliders, two rough ideas. First is possible US/European electron-positron collider of few hundred GeV. But real interest here is, of course, a next generation hadron collider running at 100 TeV. The Chinese proposal recently confirmed is the one.
Possible Europe timeline: LHC till 2020, VH-LHC till 2030. Hope to have maybe TLEP ready then for another decade, followed by ...?
Chinese machine recent announcement a surprise to scientists!
100 TeV leads to qualitatively new physics. Note that top quark at these energies is as massless as the bottom quark was at the Tevatron! So all SM particles are partons, and really working in unbroken EW phase. Even pure QCD events will be studied in completely new regimes; e.g. dijet invariant masses of 50 TeV, one event per iab. Guage boson FSR will be like radiation in QCD jets. Probe of LHC self-coupling can be resolved to order 10%. Also tests compositeness of Higgs (as a function of scale).
SUSY mass reach improved typically be a factor of 7. More generally, fine-tuning can be pushed to 10-4, which more or less answers that question.
Dark matter searches good in regions where DD fails: very light particles, or very pure winos/Higgsinos.
Finally, there's the potential to find something unexpected. Standard resonance searches give us some idea of reach. Tens of TeV in some channels.
Question
No interesting question, but Tao got provoked into the most animated speech I've ever seen from him. The crux is that we don't need to find something to justify this kind of experiment; simply understanding nature at a better scale than anyone else ever before is enough, at least it should be for scientists.
12:00 pm: Higgs Physics and Detector Design at CEPC, Manqi Ruan
Plans to run China first as electron-positron tunnel, then upgrade to hadron collider.
Detector goals: high precision vertex tracker, close to IP, for bottom, charm and tau tagging. High precision tracking to measure transverse momentum for TeV tracks at 10% level. Calorimeter suitable for jet substructure etc. Calorimeter benefit from development of microelectronics allowing ultra high granularity. Improve by ~ 1000 over LHC, gain 3D granularity.
Goal: identify every detector hit. Substantial pile up.
Measurement of Higgs width using production cross section (shape as function of energy) to resolve the coupling ambiguity. Also direct measurement of line width (3%) and tag of recoil to measure invisible width (better than 10%?). Leads to model independent measurements of Higgs couplings.
Hadron machine run benefits from luminosity, lots of tops, and energy to measure top Yukawa.
And we finish 20 minutes late.
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https://export.arxiv.org/abs/1912.01815
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math.AP
(what is this?)
# Title: Extremal case of parabolic differential equations having discontinuous unbounded coefficients. Existence of fundamental solution for an initial Cauchy problem. Parametrix method
Abstract: We prove in this short report the existence of a fundamental solution (F.S.) for the Cauchy initial boundary problem on the whole space for the parabolic differential equation having at origin the point of non-integrable unbounded discontinuity for coefficient before a first order derivative.
We give also the non-asymptotic rapidly decreasing at infinity estimate for these function.
We extend the classical parametrix method offered by E.E.Levi.
Subjects: Analysis of PDEs (math.AP) Cite as: arXiv:1912.01815 [math.AP] (or arXiv:1912.01815v1 [math.AP] for this version)
## Submission history
From: Leonid Sirota [view email]
[v1] Wed, 4 Dec 2019 06:18:05 GMT (13kb)
Link back to: arXiv, form interface, contact.
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https://pennstate.pure.elsevier.com/en/publications/data-driven-estimation-of-the-invisible-energy-of-cosmic-ray-show
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# Data-driven estimation of the invisible energy of cosmic ray showers with the Pierre Auger Observatory
The Pierre Auger Collaboration
Research output: Contribution to journalArticlepeer-review
11 Scopus citations
## Abstract
The determination of the primary energy of extensive air showers using the fluorescence detection technique requires an estimation of the energy carried away by particles that do not deposit all their energy in the atmosphere. This estimation is typically made using Monte Carlo simulations and thus depends on the assumed primary particle mass and on model predictions for neutrino and muon production. In this work we present a new method to obtain the invisible energy from events detected by the Pierre Auger Observatory. The method uses measurements of the muon number at ground level, and it allows us to significantly reduce the systematic uncertainties related to the mass composition and the high energy hadronic interaction models, and consequently to improve the estimation of the energy scale of the Pierre Auger Observatory.
Original language English (US) 082003 Physical Review D 100 8 https://doi.org/10.1103/PhysRevD.100.082003 Published - Oct 25 2019
## All Science Journal Classification (ASJC) codes
• Physics and Astronomy (miscellaneous)
## Fingerprint
Dive into the research topics of 'Data-driven estimation of the invisible energy of cosmic ray showers with the Pierre Auger Observatory'. Together they form a unique fingerprint.
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https://homework.cpm.org/category/CCI_CT/textbook/apcalc/chapter/7/lesson/7.2.3/problem/7-77
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### Home > APCALC > Chapter 7 > Lesson 7.2.3 > Problem7-77
7-77.
Differentiate each of the following functions.
1. $y = \tan^{-1}(2x)$
1. $y = \tan(2x)$
1. $y = \cot(2x)$
Compare and contrast the functions in parts (a), (b), and (c).
Match the answers with the problems, they are in no particular order:
$\frac{dy}{dx}=-2\csc^{2}(2x)$
$\frac{dy}{dx}=2\sec^{2}(2x)$
$\frac{dy}{dx}=\frac{2}{1+4x^{2}}$
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http://proofsfromthebook.com/2013/01/19/proof-that-vertical-angles-are-congruent/
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Proof that Vertical Angles Are Congruent
A pair of angles whose sides form two lines is called vertical angles. In the figure below, angles 1 and 3 are vertical angles since their sides form lines l and m. Similarly, angles 2 and 4 are vertical angles for the same reason.
Vertical angles are congruent and it is easy to prove. We just use the fact that a linear pair of angles are supplementary; that is their measures add up to $180^\circ$. In the figure above, to prove that vertical angles are congruent, we have to show that $\angle 1$ and $\angle 3$ are congruent or $\angle 2$ and $\angle 4$ are congruent.
Theorem
Vertical angles are congruent.
Proof
We show that $\angle 1 \cong \angle 3$.
$m \angle 1 + m \angle 2 = 180^\circ$ ** Linear pair of angles are supplementary.
$m \angle 2 + m\angle 3 = 180^\circ$ **Linear pair of angles are supplementary.
$m \angle 1 + m \angle 2 = m \angle 2 + m \angle 3$ ** Substitution property of equality; that is $180^\circ = 180^\circ$.
Substracting $\angle 2$ from both sides, we have
$m \angle 1 = m \angle 3$.
Therefore, vertical angles are congruent. $\blacksquare$
As an exercise, show that $m \angle 2 = m \angle 4$.
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https://math.stackexchange.com/questions/2208995/notation-for-delta-distribution
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Notation For Delta Distribution
I've encountered two different notations for the delta distribution: $$\delta(x,y)$$ and $$\delta(x-y)$$ What is the difference between these two notations. Do they depend on context or should I prefer one over the other?
• The first one is not sufficiently standard for me to even know the intended meaning. The second one is quite standard (if the variable of integration is $x$, then this can be understood as a point mass of $1$ at $y$). – Ian Mar 29 '17 at 17:33
• If the domain / space isn't additive, then $x-y$ makes no sense. But usually one writes $\delta_y$ if the mass is centered at $y$. – user251257 Mar 29 '17 at 17:38
The second describes a delta function acting along the line $x=y$:
The first notation is more convenient when working in high dimensions, since it naturally generalizes to $n$ dimensions: e.g., $\delta (x,y,z,w, ...)$. You can do this with the second notation $\delta(x) \delta(y), ...$
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http://math.stackexchange.com/questions/216391/how-to-show-that-frac-sinnn-is-1-as-n-rightarrow-0/216407
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# How to show that $\frac{\sin(n)}{n}$ is $1$ as $n \rightarrow 0$? [duplicate]
Possible Duplicate:
How to prove that $\lim\limits_{x\to0}\frac{\sin x}x=1$?
How to show that $\frac{\sin(n)}{n}$
is $1$ as $n \rightarrow 0$? just hint.
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## marked as duplicate by Martin Sleziak, AD., rschwieb, Norbert, Jason DeVitoOct 19 '12 at 1:27
Show that $\cos{x}<\frac{\sin{x}}{x}<1,x\in(-\frac{\pi}{2},\frac{\pi}{2})$ – Golbez Oct 18 '12 at 15:52
As an alternative, you can consider that limit as a derivative. – T. Verron Oct 18 '12 at 15:56
T.Verron, that may be a bit circular. You can consider the limit as a derivative, but if you can't prove this limit you can't prove the derivative. – Isaac Solomon Oct 18 '12 at 15:57
By the way how to formulate arbitrary complex trigonometric polynom? I know that in real form it is $\sum_{n=1}^{k}cos(nx)+isin(nx)$ – alvoutila Oct 18 '12 at 16:02
It is a little confusing to use the notation '$n \rightarrow 0$'. We usually reserve $n$ for natural numbers and $x$ for real numbers. Hence, for reasons of pedagogy, it is better to write '$x \rightarrow 0$'. :) – Haskell Curry Oct 18 '12 at 16:09
Maclaurin series expansion of $\sin(n)$ is,
$$\sin(n) = n - \frac{n^3}{3!} +\frac{n^5}{5!}+...$$
Hence,
$$\frac{\sin(n)}{n} = 1-\frac{n^2}{3!} + \frac{n^4}{5!}+...$$
$$\lim_{n\to 0}\frac{\sin(n)}{n} = 1$$
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This reasoning is a bit circular (unless we take the series expansion as the definition of the sine function). The Maclaurin expansion depends on the derivative of the sine function, which depends on the limit we're trying to compute. – Hans Lundmark Oct 18 '12 at 16:17
First, Prove that $\sin{x}<x<\tan{x}$, when $x\in (0,\frac{\pi}{2})$ By means of drawing a circle, take an arbitary point on the circle with coordinate $A:(\cos{x},\sin{x})$, take $B:(0,1),O:(0,0),C:(\cos{x},0),D:(\sec{x},0)$
Obviously We have $\sin{x}=S_{\Delta OAC }$, $x=S_{ OAB}$ where $S_{OAB}$ denotes the area of the circular sector, $\tan{x}=S_{\Delta OAD}$
Also, it's obvious(By drawing this circle) that $S_{\Delta OAC }<S_{ OAB}<S_{\Delta OAD}$, thus\begin{align}\sin{x}<x<\tan{x},\quad(x\in(0,\frac{\pi}{2}))\end{align}
By multiplying $-1$ on each side \begin{align}\sin{x}>x>\tan{x},\quad(x\in(-\frac{\pi}{2},0))\end{align}
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https://gitlab.mpcdf.mpg.de/ift/nifty/-/commit/4e67193280166255e63e1b6b9dd774b9ecb1dd5e
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Commit 4e671932 by Martin Reinecke
### Merge remote-tracking branch 'upstream/NIFTy_5' into simplify_for_const
parents 0fd92060 eba1fd40
image: $CONTAINER_TEST_IMAGE variables: CONTAINER_TEST_IMAGE: gitlab-registry.mpcdf.mpg.de/ift/nifty-dev:$CI_BUILD_REF_NAME CONTAINER_TEST_IMAGE: gitlab-registry.mpcdf.mpg.de/$CI_PROJECT_PATH:$CI_BUILD_REF_NAME OMP_NUM_THREADS: 1 stages: ... ... @@ -39,9 +39,9 @@ test_serial: script: - pytest-3 -q --cov=nifty5 test - > python3 -m coverage report --omit "*plot*,*distributed_do*" python3 -m coverage report --omit "*plot*,*distributed_do*" | tee coverage.txt - > python3 -m coverage report --omit "*plot*,*distributed_do*" | grep TOTAL | awk '{ print "TOTAL: "$4; }' grep TOTAL coverage.txt | awk '{ print "TOTAL: "$4; }' test_mpi: stage: test ... ... @@ -52,17 +52,15 @@ test_mpi: pages: stage: release before_script: - ls script: - python3 setup.py install --user -f - sh docs/generate.sh - mv docs/build/ public/ artifacts: paths: - public only: - NIFTy_4 - NIFTy_5 before_script: - python3 setup.py install --user -f ... ...
... ... @@ -6,7 +6,7 @@ RUN apt-get update && apt-get install -y \ # Packages needed for NIFTy python3-scipy \ # Documentation build dependencies python3-sphinx-rtd-theme \ python3-sphinx-rtd-theme dvipng texlive-latex-base texlive-latex-extra \ # Testing dependencies python3-pytest-cov jupyter \ # Optional NIFTy dependencies ... ...
... ... @@ -41,7 +41,6 @@ Abstract base class One of the fundamental building blocks of the NIFTy5 framework is the *domain*. Its required capabilities are expressed by the abstract :py:class:Domain class. A domain must be able to answer the following queries: m - its total number of data entries (pixels), which is accessible via the :attr:~Domain.size property ... ... @@ -129,7 +128,7 @@ specify full field domains. In principle, a :class:~domain_tuple.DomainTuple can even be empty, which implies that the field living on it is a scalar. A :class:~domain_tuple.DomainTuple supports iteration and indexing, and also provides the properties :attr:~domain_tuple.DomainTuple.shape, provides the properties :attr:~domain_tuple.DomainTuple.shape and :attr:~domain_tuple.DomainTuple.size in analogy to the elementary :class:~domains.domain.Domain. ... ... @@ -159,10 +158,11 @@ Contractions (like summation, integration, minimum/maximum, computation of statistical moments) can be carried out either over an entire field (producing a scalar result) or over sub-domains (resulting in a field defined on a smaller domain). Scalar products of two fields can also be computed easily. See the documentation of :class:~field.Field for details. There is also a set of convenience functions to generate fields with constant values or fields filled with random numbers according to a user-specified distribution. distribution: :attr:~sugar.full, :attr:~sugar.from_random. Like almost all NIFTy objects, fields are immutable: their value or any other attribute cannot be modified after construction. To manipulate a field in ways ... ... @@ -311,11 +311,15 @@ and f1 and f2 are of type :class:~field.Field, writing:: will perform the operation suggested intuitively by the notation, checking domain compatibility while building the composed operator. The combined operator infers its domain and target from its constituents, as well as the set of operations it can support. The properties :attr:~LinearOperator.adjoint and :attr:~LinearOperator.inverse return a new operator which behaves as if it were the original operator's adjoint or inverse, respectively. The combined operator infers its domain and target from its constituents, as well as the set of operations it can support. Instantiating operator adjoints or inverses by :attr:~LinearOperator.adjoint and similar methods is to be distinguished from the instant application of operators performed by :attr:~LinearOperator.adjoint_times and similar methods. .. _minimization: ... ... @@ -368,8 +372,8 @@ failure. Sensible stopping criteria can vary significantly with the problem being solved; NIFTy provides one concrete sub-class of :class:IterationController called :class:GradientNormController, which should be appropriate in many circumstances, but users have complete freedom to implement custom sub-classes for their specific applications. circumstances, but users have complete freedom to implement custom :class:IterationController sub-classes for their specific applications. Minimization algorithms ... ... @@ -398,7 +402,7 @@ Many minimizers for nonlinear problems can be characterized as This family of algorithms is encapsulated in NIFTy's :class:~descent_minimizers.DescentMinimizer class, which currently has three concrete implementations: :class:~descent_minimizers.SteepestDescent, generally usable concrete implementations: :class:~descent_minimizers.NewtonCG, :class:~descent_minimizers.L_BFGS and :class:~descent_minimizers.VL_BFGS. Of these algorithms, only :class:~descent_minimizers.NewtonCG requires the energy object to provide ... ... @@ -424,11 +428,13 @@ the information propagator whose inverse is defined as: :math:D^{-1} = \left(R^\dagger N^{-1} R + S^{-1}\right). It needs to be applied in forward direction in order to calculate the Wiener filter solution. Only its inverse application is straightforward; to use it in forward direction, we make use of NIFTy's filter solution, but only its inverse application is straightforward. To use it in forward direction, we make use of NIFTy's :class:~operators.inversion_enabler.InversionEnabler class, which internally performs a minimization of a :class:~minimization.quadratic_energy.QuadraticEnergy by means of the :class:~minimization.conjugate_gradient.ConjugateGradient algorithm. An example is provided in applies the (approximate) inverse of the given operator :math:x = Op^{-1} (y) by solving the equation :math:y = Op (x) for :math:x. This is accomplished by minimizing a suitable :class:~minimization.quadratic_energy.QuadraticEnergy with the :class:~minimization.conjugate_gradient.ConjugateGradient algorithm. An example is provided in :func:~library.wiener_filter_curvature.WienerFilterCurvature.
... ... @@ -4,8 +4,7 @@ IFT -- Information Field Theory Theoretical Background ---------------------- Information Field Theory _ [1]_ (IFT) is information theory, the logic of reasoning under uncertainty, applied to fields. Information Field Theory _ [1]_ (IFT) is information theory, the logic of reasoning under uncertainty, applied to fields. A field can be any quantity defined over some space, e.g. the air temperature over Europe, the magnetic field strength in the Milky Way, or the matter density in the Universe. IFT describes how data and knowledge can be used to infer field properties. Mathematically it is a statistical field theory and exploits many of the tools developed for such. ... ... @@ -22,89 +21,18 @@ NIFTy comes with reimplemented MAP and VI estimators. .. tip:: *In-a-nutshell introductions to information field theory* can be found in [2]_, [3]_, [4]_, and [5]_, with the latter probably being the most didactical. .. [1] T.A. Enßlin et al. (2009), "Information field theory for cosmological perturbation reconstruction and nonlinear signal analysis", PhysRevD.80.105005, 09/2009; [arXiv:0806.3474] _ .. [1] T.A. Enßlin et al. (2009), "Information field theory for cosmological perturbation reconstruction and nonlinear signal analysis", PhysRevD.80.105005, 09/2009; [arXiv:0806.3474] _ .. [2] T.A. Enßlin (2013), "Information field theory", proceedings of MaxEnt 2012 -- the 32nd International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Engineering; AIP Conference Proceedings, Volume 1553, Issue 1, p.184; [arXiv:1301.2556] _ .. [2] T.A. Enßlin (2013), "Information field theory", proceedings of MaxEnt 2012 -- the 32nd International Workshop on Bayesian Inference and Maximum Entropy Methods in Science and Engineering; AIP Conference Proceedings, Volume 1553, Issue 1, p.184; [arXiv:1301.2556] _ .. [3] T.A. Enßlin (2014), "Astrophysical data analysis with information field theory", AIP Conference Proceedings, Volume 1636, Issue 1, p.49; [arXiv:1405.7701] _ .. [3] T.A. Enßlin (2014), "Astrophysical data analysis with information field theory", AIP Conference Proceedings, Volume 1636, Issue 1, p.49; [arXiv:1405.7701] _ .. [4] Wikipedia contributors (2018), "Information field theory" _, Wikipedia, The Free Encyclopedia. .. [5] T.A. Enßlin (2019), "Information theory for fields", accepted by Annalen der Physik; [DOI] _, [arXiv:1804.03350] _ Discretized continuum --------------------- The representation of fields that are mathematically defined on a continuous space in a finite computer environment is a common necessity. The goal hereby is to preserve the continuum limit in the calculus in order to ensure a resolution independent discretization. +-----------------------------+-----------------------------+ | .. image:: images/42vs6.png | .. image:: images/42vs9.png | | :width: 100 % | :width: 100 % | +-----------------------------+-----------------------------+ Any partition of the continuous position space :math:\Omega (with volume :math:V) into a set of :math:Q disjoint, proper subsets :math:\Omega_q (with volumes :math:V_q) defines a pixelization, .. math:: \Omega &\quad=\quad \dot{\bigcup_q} \; \Omega_q \qquad \mathrm{with} \qquad q \in \{1,\dots,Q\} \subset \mathbb{N} , \\ V &\quad=\quad \int_\Omega \mathrm{d}x \quad=\quad \sum_{q=1}^Q \int_{\Omega_q} \mathrm{d}x \quad=\quad \sum_{q=1}^Q V_q . Here the number :math:Q characterizes the resolution of the pixelization and the continuum limit is described by :math:Q \rightarrow \infty and :math:V_q \rightarrow 0 for all :math:q \in \{1,\dots,Q\} simultaneously. Moreover, the above equation defines a discretization of continuous integrals, :math:\int_\Omega \mathrm{d}x \mapsto \sum_q V_q. Any valid discretization scheme for a field :math:{s} can be described by a mapping, .. math:: s(x \in \Omega_q) \quad\mapsto\quad s_q \quad=\quad \int_{\Omega_q} \mathrm{d}x \; w_q(x) \; s(x) , if the weighting function :math:w_q(x) is chosen appropriately. In order for the discretized version of the field to converge to the actual field in the continuum limit, the weighting functions need to be normalized in each subset; i.e., :math:\forall q: \int_{\Omega_q} \mathrm{d}x \; w_q(x) = 1. Choosing such a weighting function that is constant with respect to :math:x yields .. [5] T.A. Enßlin (2019), "Information theory for fields", accepted by Annalen der Physik; [DOI] _, [arXiv:1804.03350] _ .. math:: s_q = \frac{\int_{\Omega_q} \mathrm{d}x \; s(x)}{\int_{\Omega_q} \mathrm{d}x} = \left< s(x) \right>_{\Omega_q} , which corresponds to a discretization of the field by spatial averaging. Another common and equally valid choice is :math:w_q(x) = \delta(x-x_q), which distinguishes some position :math:x_q \in \Omega_q, and evaluates the continuous field at this position, .. math:: s_q \quad=\quad \int_{\Omega_q} \mathrm{d}x \; \delta(x-x_q) \; s(x) \quad=\quad s(x_q) . In practice, one often makes use of the spatially averaged pixel position, :math:x_q = \left< x \right>_{\Omega_q}. If the resolution is high enough to resolve all features of the signal field :math:{s}, both of these discretization schemes approximate each other, :math:\left< s(x) \right>_{\Omega_q} \approx s(\left< x \right>_{\Omega_q}), since they approximate the continuum limit by construction. (The approximation of :math:\left< s(x) \right>_{\Omega_q} \approx s(x_q \in \Omega_q) marks a resolution threshold beyond which further refinement of the discretization reveals no new features; i.e., no new information content of the field :math:{s}.) All operations involving position integrals can be normalized in accordance with the above definitions. For example, the scalar product between two fields :math:{s} and :math:{u} is defined as .. math:: {s}^\dagger {u} \quad=\quad \int_\Omega \mathrm{d}x \; s^*(x) \; u(x) \quad\approx\quad \sum_{q=1}^Q V_q^{\phantom{*}} \; s_q^* \; u_q^{\phantom{*}} , where :math:\dagger denotes adjunction and :math:* complex conjugation. Since the above approximation becomes an equality in the continuum limit, the scalar product is independent of the pixelization scheme and resolution, if the latter is sufficiently high. The above line of argumentation analogously applies to the discretization of operators. For a linear operator :math:{A} acting on some field :math:{s} as :math:{A} {s} = \int_\Omega \mathrm{d}y \; A(x,y) \; s(y), a matrix representation discretized with constant weighting functions is given by .. math:: A(x \in \Omega_p, y \in \Omega_q) \quad\mapsto\quad A_{pq} \quad=\quad \frac{\iint_{\Omega_p \Omega_q} \mathrm{d}x \, \mathrm{d}y \; A(x,y)}{\iint_{\Omega_p \Omega_q} \mathrm{d}x \, \mathrm{d}y} \quad=\quad \big< \big< A(x,y) \big>_{\Omega_p} \big>_{\Omega_q} . The proper discretization of spaces, fields, and operators, as well as the normalization of position integrals, is essential for the conservation of the continuum limit. Their consistent implementation in NIFTy allows a pixelization independent coding of algorithms. Free Theory & Implicit Operators -------------------------------- ... ... @@ -205,11 +133,11 @@ NIFTy takes advantage of this formulation in several ways: 3) The response can be non-linear, e.g. :math:{R'(s)=R \exp(A\,\xi)}, see demos/getting_started_2.py. 4) The amplitude operator may dependent on further parameters, e.g. :math:A=A(\tau)= F\, \widehat{e^\tau} represents an amplitude operator with a positive definite, unknown spectrum defined in the Fourier domain. 4) The amplitude operator may depend on further parameters, e.g. :math:A=A(\tau)= F\, \widehat{e^\tau} represents an amplitude operator with a positive definite, unknown spectrum defined in the Fourier domain. The amplitude field :math:{\tau} would get its own amplitude operator, with a cepstrum (spectrum of a log spectrum) defined in quefrency space (harmonic space of a logarithmically binned harmonic space) to regularize its degrees of freedom by imposing some (user-defined degree of) spectral smoothness. 5) NIFTy calculates the gradient of the information Hamiltonian and the Fisher information metric with respect to all unknown parameters, here :math:{\xi} and :math:{\tau}, by automatic differentiation. The gradients are used for MAP and HMCF estimates, and the Fisher matrix is required in addition to the gradient by Metric Gaussian Variational Inference (MGVI), which is available in NIFTy as well. The gradients are used for MAP estimates, and the Fisher matrix is required in addition to the gradient by Metric Gaussian Variational Inference (MGVI), which is available in NIFTy as well. MGVI is an implicit operator extension of Automatic Differentiation Variational Inference (ADVI). The reconstruction of a non-Gaussian signal with unknown covariance from a non-trivial (tomographic) response is demonstrated in demos/getting_started_3.py. ... ... @@ -296,7 +224,7 @@ Thus, only the gradient of the KL is needed with respect to this, which can be e We stochastically estimate the KL-divergence and gradients with a set of samples drawn from the approximate posterior distribution. The particular structure of the covariance allows us to draw independent samples solving a certain system of equations. This KL-divergence for MGVI is implemented in the class MetricGaussianKL within NIFTy5. This KL-divergence for MGVI is implemented in the class :class:~minimization.metric_gaussian_kl.MetricGaussianKL within NIFTy5. The demo getting_started_3.py for example not only infers a field this way, but also the power spectrum of the process that has generated the field. ... ...
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https://www.gradesaver.com/textbooks/math/algebra/algebra-2-1st-edition/chapter-10-counting-methods-and-probability-chapter-review-page-735/18
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Algebra 2 (1st Edition)
Since there are 10 numbers between 1 and 30 that are prime, it follows: $$=\frac{10}{30}=\frac{1}{3}$$
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https://enjeeneer.io/talks/2021-06-03-jesusmcrgreen/
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Abstract
Recent advances in the field of Reinforcement Learning, a subfield of Artificial Intelligence, have shown computers can achieve superhuman performance at complex games like Go, Starcraft and the Atari Suite without human knowledge. What if, instead of playing Space Invaders, we play the game of climate change mitigation? More specifically, how can we design games where the goal is to minimise carbon emissions in some setting, and learn to play them optimally? In this talk, we’ll first establish the importance of using less energy and material to limit planet-cooking, then we’ll take the first steps toward formulating a game whose solution could help to mitigate climate change.
Code
Slides
# 0. Outline
1. Space Invasion: the footprint of climate chang e mitigation
2. Space Invaders: learning to control complex systems optimally
3. An Emission-minimisation Game
# 1. Space Invasion
Climate change mitigation is fundamentally an energy problem; society requires energy of all forms to function, and this energy still comes largely from sources that emit greenhouse gases that cause global warming. With that in mind, we can think of energy as the calories of our economies, and we can frame climate change mitigation as a diet that we must embark on. Like any diet, there are three things we can do to lose weight. Firstly, we can eat healthier meals, or get our energy from cleaner sources. We can think of this as analogous to generating energy from renewable energy resources like wind or solar. Secondly, we can eat less food, or use less energy in our lives. In our research group we call this Resource Efficiency, or maintaining the same final service for less energy input. And finally, we can keep eat the same rubbish food in similar amounts, and just exercise a few hours a day to try and burn off the calories. This is analogous to carbon capture and storage, where we continue to emit carbon dioxide by burning fossil fuels, but attach a hoover to the exhaust of the power station or industrial process and bury the gases in the same oilfield you just plucked the fossil fuels from.
So these are our climate change mitigation options. The UK has focussed largely on option 1 (renewable energy) to-date, and all of their projections rely on option 3 (carbon capture), little attention is given to motivating resource efficiency; in much the same way people prefer not to tell you to eat less when dieting. I’m going to talk initially about the problems associated with the UK’s plans, and how my research looks to address it.
## Low Carb(on) Diet
To do that, I need to introduce you to our unit of measurement for this diet. Instead of using the calorie, we’ll use the kilowatt-hour (kWh), the SI unit for measuring energy. To give you a sense of scale, here’s our current energy diet, and the number of kWhs associated with some everyday activities.
Leaving one 40W lightbulb on for 24 hours will use about 1kWh of energy. An aluminium can of coke requires about 0.6kWh of energy to be produced. A hot bath will cost you 5kWh. And burning 1 litre of petrol in your car by driving 5 or 6 miles will use 10kWh of energy. If we sum all activities you do daily, we find that the average person in the UK uses about 125kWh/day. Instead of quantifying energy use on a daily basis, we can convert this volume of energy to a flow rate of energy that we call power, measured in watts rather than watt-hours. So 125kWh/day of energy is equivalent to a 5kW power source consuming power for the whole day, similar to two cookers being left on at 200 degrees all day.
So this is your life, two cookers on all the time, one for the left hemisphere of your brain and one for the right. So to continue to live your life as you do today, you need to go out in the world and find a 5kW power source and have it on all day, offsetting the energy you are using elsewhere in your life. So let’s think about doing that; if you’re going to go out and find a source of power, your going to need a piece of land to put in on. How much land would you like? Well let’s give everyone in the country a fair share of land.
## Our Energy Diet
💡 → 1kWh
🥤 → 0.6kWh
🛁 → 5kWh
🚗 → 10kWh
💁♀️ → 125kWh/day or 5kW → 🎛🎛
after MacKay (2008)
The population of the UK is 66.65 million apparently, and the total area of land in the UK is 242,495 square kilometres. If we divide the top one by the bottom one, we find that each person in the UK gets about 3600 square metres of space to store their energy generating devices, which is about equivalent to half a football pitch. We can do one more calculation to find the power density of your life: by taking the power rating of your life (5kW) and dividing it by your allotment size (3600m2) we find that your life costs 2.5 W/m2.
Now, this is a useful figure to obtain, because each of those energy generating devices you’re about to go and source are also quantified in this way, so we see how likely it is for each of the technologies to power your life.
## Your Allotment for Energy Generation
• UK population: 66.65 million
• UK land area: 242,495 km²
• Your allotment: 3600m² ~ half a football pitch
• Your life: ~2.5 W/m$^2$
after MacKay (2008)
Here’s a table of the most common energy generating technologies. The middle column is their power density, or power output per unit land area, and the final column is an indication of whether they are zero-emission or otherwise. (The pinnochio face is reserved for technologies that are often said to be renewable, but are, in fact, not). So, remember your life requires 2.5 W/m2, what the first entry in the table is telling us is that to power your life using solely wind power we need to cover your entire allotment (and everyone else’s allotment) in wind turbines. If we wanted to use solar power, we’d need to cover about half of your football pitch in solar panels. If we wanted to use nuclear power, we would only need to use about 1% of your football pitch. And so on. So let’s try and visualise some of these interventions.
## Space Requirements of Energy Generating Devices
Your life: ~2.5 W/m$^2$
Technology ~ Power Per Unit Land Area Zero Operational Emissions
Wind 2.7 W/m$^2$ 💚
Biomass 1 W/m$^2$ 🤥
Solar 6 W/m$^2$ 💚
Hydropower 0.9 W/m$^2$ 🤥
Geothermal 3 W/m$^2$ 💚
Natural Gas 1300 W/m$^2$ ⛔️
Coal 125 W/m$^2$ ⛔️
Oil 180 W/m$^2$ ⛔️
Nuclear 300 W/m$^2$ 💚
Data: van Zalk & Behrens (2018)
If you want to reserve some space for living your life, rather than just producing energy, you’ll want to cordan that off. Here’s is 40% of your land blocked off, which represents the area of UK land currently used for cities and for countryside Bossard & Otahel (2000).
But we’ll find later on that we might need some of that land to avoid turning the UK into a desert, so it’s back on the table for now:
Let’s take a look at how this land has been used through the years. This was (very) roughly the UK between the beginning of the industrial revolution and the 1980s. Most electricity coming from coal, and oil used for transportation and some heating.
Then Mrs Thatcher came to power in the 1980s, closed most of the coal mines and replaced them with natural gas power plants of higher power density and lower emission intensity, and the energy mix looked something like this. Note: energy generation is using approximately 1% of land area here, plenty of room to continue live out the glorious 80s whilst the planet slowly begins to simmer.
Here’s (very) roughly where we are today, we have a mix of natural gas, biomass, wind, solar and nuclear; with the area of land they cover flattered by the fact that 40% of our energy is sourced from natural gas. The important takeaway from this diagram is the arbitrarily sized chequered box representing imported energy. Much of the goods and services that contribute to your 125kWh per day energy usage are imported; the aluminium in your coke can, the steel in your car. To fund our lifestyles in the UK, we are effectively outsourcing a large amount of energy production (and associated emissions), moving the energy generating devices from our land to somebody else’s land. This may be okay today, when the energy generating devices elsewhere are natural gas or coal and don’t take up much land. But when these countries attempt to decarbonise and find they are being asked or required to build solar panels on their countryside, I suspect they are going to come back to the UK and say ‘wait a minute, you deal with these emissions, you’re causing them’. This gives us a false sense of how much land the energy required to fuel our lifestyles is taking up.
So, to me, it seems only fair that we consider scenarios where we generate an amount of energy proportional to our lifestyles. And that is what we will consider now.
%">
If we were to generate energy using only wind and solar, we would use approximately 70% of UK land area, remember cities and countryside account for 40% of land area so we are eating into our leisure area now.
There are various ways to stop this space invasion, and one of them is to shrink the size of the energy pie; to use less energy in our society; to be more resource efficient. That is the focus of our research group’s work, and that is one of the goals of my research. So, if we want to reduce our energy demand, what are our options, and where should our prioritises lie.
## Reducing energy demand: what are our options?
Cullen & Allwood (2010)
Above is work done by my supervisor, Jon Cullen, in 2010, mapping the relationship between energy sources and final services, via the devices that produce this transformation. I’d like to first focus your attention on the middle slice of the five illustrated. You’ll see that approximately half of global energy supply is used to produce or extract heat (red); the most obvious example of this being in the heating and cooling of homes, other examples include powering furnaces in manufacturing facilities, or in heating water. Just over a third of our energy is used to produce motion (cyan), be it powering cars, trucks or planes, or in moving heavy machinery in manufacturing. And just over 15% of energy remains for what Jon describes as ‘Other’ (black) which involves lighting, communication, and myriad of less energy-intensive services.
My research looks to affect a few parts of this diagram:
I’m interested in how the small cyan line in the bottom left hand corner: renewable energy, integrates with the energy conversion devices, and final services. Although small on this diagram, this was the global energy mix in 2005, by 2050 we expect renewable energy to supply approximately 70% of world energy. Unlike fossil fuel power stations, we cannot control when renewable energy resources will produce electricity because their ability to do so is weather dependent. For example, solar panels will produce energy during the daytime when the sun has risen, but not at night when the sun has set. We therefore say renewable energy technologies are intermittent. I’ll explain the intermittency problem visually:
Let’s consider the problem of trying to power a flat on Park Street for one day using a 10kW array of solar panels on the roof. The orange line here traces power output of the panels throughout the day, when the sun rises in the morning it begins to produce energy, it’s power output peaks at some point in the early afternoon and then drops to 0 after the sun has set. In contrast the energy demand of the flat occupants is lumpy, there’s a peak around 7am when people get in the shower and put the kettle on for a coffee; if they go out to work for the day the power demand drops in the morning and afternoon, then when they come home and putting the heating, oven and tv in there’s another spike.
## The Intermittency Problem
This creates scenarios throughout the day where there are deficits and surplusses in energy. In green, energy generation exceeds demand, so we meet our energy requirements renewably, but in the absence of a battery waste chunks of zero-emission energy. In red, demand outstrips what the panels supply. In these scenarios today, these peaks of excess supply are met by firing up natural gas plants at short notice to provide the energy, creating further emissions.
What we would prefer is a scenario like this one. Here we’ve done two things: we flattened and broadened the demand curve, so there are no peaks to meet with natural gas; and we’ve introduced a storage medium - potentially a battery. During the hours of peak production we store energy (represented by orange) and we discharge this energy when needed, represented in blue. Here, we’ve reduced our total energy demand by flattening the peak, and we’ve stopped the mitigated the problem of peak matching with natural gas - saving emissions in two ways.
This is of course an idealised representation of what we’d like to do at both a household and national scale, and it makes it look simpler that it is. In reality, both the the supply curve and the demand curve are stochastic, and matching them is a highly complex optimisation problem.
To do so we need to accurately predict renewable energy supply at various time horizons; in the next 5 minutes and in the next 5 hours, and everywhere in between. Equally we need to predict energy demand, which, depending on the situation can be affected by countless variables. In the household setting, the energy demand is largely affected by weather conditions (i.e. if it’s cold outside heating demand increases) and time of day (if it’s 7am somebody probably wants a shower). In the industrial setting, perhaps a car manufacturing plant, the energy demand of the plant may be affected by sales forecasts, and raw material delivery schedules.
Attempting to solve this problem requires some sophisticated techniques, and my research centres on a subfield of artificial intelligence called Reinforcement Learning (RL). Which I’ll take about now, in section 2: space invaders.
## Intermittency: A non-trivial optimisation problem
• Stochastic supply:
• Weather-dependent
• Need accurate predictions of supply at varied time horizons: 5mins; 5 hours; 5 days
• Stochastic demand:
• Depending on scenario, affected by countless variables
• Household setting: outdoor temperature; time of day; day of week
• Industrial setting: sales forecasts; raw material delivery schedules
Reinforcement learning is the eminent paradigm for allowing computers to learn from experience. In RL, we consider an agent (represented by the brain) interacting with an environment (represented by the globe). The agent can take actions in an environment, and at each timestep step it receives feedback on how the state of the environment has changed given that action, and a reward for taking that action. The goal of the RL agent is to maximise the sum of cumulative rewards throughout its lifetime. When an RL agent is instantiated, it has no understanding of its environment or valuable actions to take in the environment, but learns by taking actions in the environment, in a trial and error fashion, observing the reward it accrues, and updating it’s understanding of the state-space. It’s hypothesised that this is much the same way we as humans learn intelligently. Consider the example of learning to ride a bike; we don’t necessarily understand the physics of bike-riding, instead we get on the bike, try to balance and cycle and see what works for us. We find, through trial and error, the optimal way to position our body to balance the bike.
Although this appears a simple paradigm, it elicits extremely powerful behaviour from computers.
## Reinforcement Learning
Silver (2015)
Some of the best examples of this powerful behaviour come from the gaming domain. Here’s an RL agent, created by DeepMind in 2013, that learns to play the Atari game breakout with no prior knowledge or human input. The agent is fed minimal data; it’s fed the raw pixels of the screen as a representation of the state; it’s knows it can take three actions: move left, move right, or stay still, and it’s fed the score at the top of the screen as a reward signal.
You can see initially it struggles to hit the ball, but slowly it learns first to connect with the ball. Then by episode 600 it exhibits some pretty intelligent behaviour; it discovers that the optimally strategy is to burrow holes in the channels of the bricks and ping the ball behind the bricks.
To give you a little more intuition about what is happening under the hood of an RL agent, let’s return quickly to the breakout example.
There are various ways in which the agent can represent its understanding of the system, but one is by assigning each part of the state-space (the environment) a value, and iterating it’s formulation of that value as it receives rewards from the environment.
Here we see a plot of the agent’s value estimate for the current state of the environment over time. We see a spiky pattern in the value estimate; just before the ball hits it bricks it has learned that it will receive reward shortly and estimates high value, then the value estimate drops as it knows it would receive more reward until some time into the future.
# 3. An Emission-Minimising Game
So I’ve introduced RL, and discussed how agents can learn to play extremely complex games with no prior knowledge to a superhuman level. I’ve also motivated the need to reduce energy-use as a climate change mitigation technique. I’m going to conclude by combining these two sections together, and discuss formulating an emission-minimising game and how we can go about finding a solution.
The game we’re going to play is controlling the energy-intensive equipment in an industrial-sized coldstorage facility in Canada. I work with a US company called Emerson Electric who own 10,000 or so of these facilities across North America; they act as a middle-ground between food manufacturers and supermarkets, that is to say, food manufacturers delivery fresh food here, the food is held for some period of time before it is picked up and delivered to supermarkets. It’s a big facility, a few football pitches in size, and consumes a lot of energy - approximately XX amount. We want to build an RL agent that can learn to control the equipment in this facility, and smooth demand in much the same way that I described earlier on with the solar PV example.
## 3.1 Formulating the Game
• Moves:
• Chiller control: $\sum_{n=1}^6 a_t^n \in \mathcal{A}$, with $\mathcal{A} = [0\text{kW}, 5\text{kW}]$
• Goal:
• Minimise energy-use: $\min{E_t}$, while
• Maintain temperature: $T_t \leq 3^0C$
• Environment dynamics (transition function):
• ???
• $\mathbb{P}(s_{t+1}, r_{t} | s_t, a_t)$
So let’s build the game. Each game has three aspects, the moves we can take, its goal and the environment dynamics or transition function.
Our available moves are related to the 6 chiller units in the facility, these are what use energy and regulate the temperature. We can actuate each of these 6 chillers in the continuous region between 0kW and 5kW, where 0kW is the chiller off and 5kW is the chiller at full power.
Our goal is twofold: minimise energy-use in the facility whilst maintaining the temperature below 3 degrees celcius which is the safe temperature range for the food inside.
Finally the environment dynamics or transition function - something I haven’t yet discussed. The is a mapping that represents how the state of the environment evolves given our actions from some state. In the Atari example, it’s straightforward: I move the joystick right and the paddle moves to the right; in our example it’s more complex and not obvious. How the temperature in the room changes given the agents actions is complex and non-linear. We need to learn this so that we can setup a simulator of the environment that the agent can play in and learn to control.
The details of how this is done is the topic for another talk, but in summary we use other supervised machine learning techniques to do this.
## Learning the Environment Dynamics/Transition Function
Here’s a representation of the transition function, estimated using a Gaussian Process. In red, is how the temperature of the coldstorage facility varied over a few day last July given the actions of the existing controller. In green, is our transition function’s prediction of what happened in that same time period, and you can see it’s pretty accurately characterised the dynamics of the system given chiller actuation.
## 3.2 Playing the Game
Now that we’ve set up the game let’s play. We play it for 200, one month episodes in simulation, this is the same as practicing controlling the facility for about 15 years. The y-axis here is cumulative reward per episode; you can see it starts out poorly, with no idea how to control the system, but quickly learns which actions are good ones. After about 50 episodes we’re at near-optimal behaviour.
## 3.3. Winning the Game
Let’s now compare our agent with the existing controller by running it through the same scenarios it was required to. Here’s one day’s plot from last September. In blue is the combined power output of the chillers, and in dashed purple is the average temperature in the facility. You can see quite stochastic behaviour, and the temperature is not regulated particularly well.
Let’s now run our RL agent in the same setting and see what happens. So the first thing to note is the green-dotted line. Our agent has learned to control the facility at just below 3 degrees Celsius and used much less power as a result. It also smooths the spiky nature of demand. I should point out, that this sort of behaviour is unlikely in the real world, because unforeseen stochasticities will inevitably push the temperature beyond 3 degrees, so we would likely set the agent to control for, say 2.7 degrees to account for this.
## Limitations
• Sample inefficiency
• Robustness to out of distribution events
• No online learning
## Next Steps
• Incorporate grid stochasticity
• Incorporating uncertainty
• Improve data-efficiency
• Consider multi-agent systems
I’ll end with some limitations and next steps. Firstly the limitations, you’ll note that I said this agent trained on 15 years of simulation, this is completely unrealistic for real settings. The agent may not be robust to out of distribution, unforeseen events and we need to address that. And there is no online learning, these models were trained using data from the facility, again to scale this approach to every energy-intensive building around the world we need to stick a box to the side of a building and learn with no prior knowledge.
Next steps for me and to incorporate the grid stochasticity that I discussed in the toy example; try and incorporate uncertainty into the agent’s action selection to improve robustness; use or adapt new algorithms to improve data-efficiency; and consider multi-agent systems where many agents are trying to draw power from the grid simultaneously.
# Thanks!
## References
Bossard, M., Feranec, J., & Otahel, J. (2000). CORINE land cover technical guide: Addendum 2000.
Cullen, J. M., & Allwood, J. M. (2010). The efficient use of energy: Tracing the global flow of energy from fuel to service. Energy Policy, 38(1), 75-81.
MacKay, D. (2008). Sustainable Energy-without the hot air. UIT cambridge.
Mnih, V., Kavukcuoglu, K., Silver, D., Graves, A., Antonoglou, I., Wierstra, D., & Riedmiller, M. (2013). Playing atari with deep reinforcement learning. arXiv preprint arXiv:1312.5602.
Silver, D., Schrittwieser, J., Simonyan, K., Antonoglou, I., Huang, A., Guez, A., … & Hassabis, D. (2017). Mastering the game of go without human knowledge. nature, 550(7676), 354-359.
Silver, D. (2015). Lecture 1: Introduction to reinforcement learning. Google DeepMind, 1, 1-10.
van Zalk, J., & Behrens, P. (2018). The spatial extent of renewable and non-renewable power generation: A review and meta-analysis of power densities and their application in the US. Energy Policy, 123, 83-91.
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http://biostat.mc.vanderbilt.edu/wiki/Main/DocProcess
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# General Information about LaTeX and other Document Processing Tools
\usepackage{sinput} % User must define \scom to specify how S comments are typeset
\newcommand{\scom}[1]{{\rm\scriptsize \# #1}}
\begin{document}
\sinput{mysprog.s} % myprog.s is an ordinary S script
\end{document}
Thanks to Terry Cox for showing me how to do this.
-- FrankHarrell - 08 Apr 2004, modified 13 May 2004, 20 Jun, 5 Sep, 12 Sep, 3 Oct, 11 Oct 2004, 1 Jan, 23 Feb, 11 May 2005, 6 Apr, 21 Oct 2006, 15 Mar, 19 Jul, 5 Aug, 21 Aug, 17 Sep 2007, 17 Jan, 28 May 2009, 1 Mar, 16 Mar, 27, 31 May 2010, 16 Feb, 2 Oct 2012, 2014-07-19
Topic attachments
I Attachment Action Size Date Who Comment
ps Measures.ps manage 320.4 K 06 Dec 2004 - 13:37 JonathanSchildcrout
tex Measures.tex manage 37.1 K 06 Dec 2004 - 13:46 JonathanSchildcrout
EXT getlatex manage 0.5 K 01 Mar 2014 - 08:36 FrankHarrell Authors: Hans Ekbrand & Frank Harrell
EXT getlatexfrom manage 0.2 K 01 Mar 2014 - 08:38 FrankHarrell Get LaTeX package from a specific locatiion
q plots.q manage 2.6 K 06 Dec 2004 - 13:46 JonathanSchildcrout
Topic revision: r42 - 06 Jun 2015, FrankHarrell
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https://lessonplanet.com/teachers/evaluating-informaton-quality
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# Evaluating Informaton Quality
Sixth graders investigate the concept of the quality of information that is used to conduct research. They begin to conceive the differences between information that is fact or fiction. Students write a critique of an information source and identify its point of view.
Resource Details
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http://eprint.iacr.org/2004/294
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## Cryptology ePrint Archive: Report 2004/294
Solving Systems of Differential Equations of Addition and Cryptanalysis of the Helix Cipher
Souradyuti Paul and Bart Preneel
Abstract: Mixing addition modulo 2^n (+) and exclusive-or has a host of applications in symmetric cryptography as the operations are fast and nonlinear over GF(2). We deal with a frequently encountered equation (x+y)XOR((x XOR a)+(y XOR b))=c$. The difficulty of solving an arbitrary system of such equations -- named differential equations of addition (DEA) -- is an important consideration in the evaluation of the security of many ciphers against differential attacks. This paper shows that the satisfiability of an arbitrary set of DEA -- which has so far been assumed \emph{hard} for large$n$-- is in the complexity class P. We also design an efficient algorithm to obtain all solutions to an arbitrary system of DEA with running time linear in the number of solutions. Our second contribution is solving DEA in an adaptive query model where an equation is formed by a query (a,b) and oracle output c. The challenge is to optimize the number of queries to solve (x+y)XOR((x XOR a)+(y XOR b))=c. Our algorithm solves this equation with only 3 queries in the worst case. Another algorithm solves the equation (x+y)XOR(x+(y XOR b))=c$ with (n-t-1) queries in the worst case (t is the position of the least significant `1' of x), and thus, outperforms the previous best known algorithm by Muller -- presented at FSE~'04 -- which required 3(n-1) queries. Most importantly, we show that the upper bounds, for our algorithms, on the number of queries match worst case lower bounds. This, essentially, closes further research in this direction as our lower bounds are optimal.
We used our results to cryptanalyze a recently proposed cipher Helix, which was a candidate for consideration in the 802.11i standard. We are successful in reducing the data complexity of a DC attack on the cipher by a factor of 3 in the worst case (a factor of 46.5 in the best case).
Category / Keywords: Differential Cryptanalysis, Helix cipher, P, NP
Publication Info: An Extended Abstract of this Paper will be published in the proceedings of ACISP 2005
Date: received 7 Nov 2004, last revised 7 Nov 2012
Contact author: Souradyuti Paul at esat kuleuven ac be
Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | PDF | BibTeX Citation
Note: A proper subset of the results of this report under the title "Optimal Lower Bounds on the Number of Queries for Solving Differential Equations of Addition" had resided here till April 20, 2005.
[ Cryptology ePrint archive ]
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https://www.physicsforums.com/threads/superposition-waves.198866/
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# Superposition waves
1. Nov 17, 2007
### Nghi
1. The problem statement, all variables and given/known data
Two wave pulses on a string approach one another at the time t = 0, as shown in the figure below, except that pulse 2 is inverted so that it is a downward deflection of the string rather than an upward deflection. Each pulse moves with a speed of 1.0 m/s. Assume that the superposition principle holds for these waves, and that the absolute value of the height of each pulse is 1 mm in the figure below. Determine the value of the resultant wave at x = 4.1 m at t = 1.0 s, 2.0 s, 2.5 s, 3.0 s, and 4.0 s.
2. Relevant equations
None? o_o
3. The attempt at a solution
Sorry to bother everyone on the same day again, but everyone is just so helpful on this forum! :) This one makes my heart sad because I don't know how to find the slope of pulse 2, which is essentially a straight line. :(
The only solutions I didn't get were t = 2.0 s and 2.5 s. But I think if I understood how to do 2.0 s, then 2.5 would be manageable.
I understand the idea of superposition, but I don't know how to apply it, I guess. Ha ha. :'( My friend mentioned something about finding the slope of pulse 2 first, but I don't know how to do that. I think it's because I'm underthinking.
2. Nov 18, 2007
### chaoseverlasting
The slope of pulse two may be found using the graph. You know the height and the width of the pulse.
Similar Discussions: Superposition waves
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http://ito.wias-berlin.de/publications/wias-publ/run.jsp?template=abstract&type=Preprint&year=1999&number=502
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WIAS Preprint No. 502, (1999)
# Simulation of Rare Events by the Stochastic Weighted Particle Method for the Boltzmann Equation
Authors
• Rjasanow, Sergej
• Wagner, Wolfgang
2010 Mathematics Subject Classification
• 65C05 76P05 82C80
Keywords
• Boltzmann equation, stochastic particle method, rare events, variance reduction, numerical experiments
DOI
10.20347/WIAS.PREPRINT.502
Abstract
An extension of the stochastic weighted particle method for the numerical treatment of the Boltzmann equation is presented. A new procedure for modelling the inflow boundary condition is introduced and its performance is tested in a two-dimensional example with strong density gradients. A gain factor in computing time of several orders of magnitude is achieved in specific situations.
Appeared in
• Math.Comput. Modelling 33 (2001), no. 8-9, pp. 907-926
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https://tex.stackexchange.com/questions/501780/longtable-vertical-line-not-complete
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# Longtable: Vertical Line not complete
I am using the longtable LaTeX package to create a multi-page table with three columns, one of which contains only images. However, the vertical line between the middle and right column does not complete up to the top \hline as seen in the screenshot.
This is the code I'm using to create the table. I removed most of the lines to make it viable easier because it's basically the same line repeated over.
\begin{longtable}{m{0.5\textwidth}|m{0.25\textwidth}|m{0.15\textwidth}}
Thumbnail & Description & Number of Images \\
\hline \\
\includegraphics[width=0.45\textwidth]{img/data/some_img1.png} & Description 1 & 2 \\
\includegraphics[width=0.45\textwidth]{img/data/some_img2.png} & Description 2 & 10 \\
\caption{Gathered Data}
\label{tbl:some_data_table}\\
\end{longtable}
Thanks!
• Welcome to TeX.SE! Remove \\ after first \hline. – Zarko Jul 28 at 1:13
As Zarko already mentioned in the comments, you can get rid of the undesired gap in the vertical line by removing the \\ after \hline:
\documentclass{article}
\usepackage{longtable}
\usepackage{graphicx}
\usepackage{array}
\begin{document}
\begin{longtable}{m{0.5\textwidth}|m{0.25\textwidth}|m{0.15\textwidth}}
Thumbnail & Description & Number of Images \\
\hline
\includegraphics[width=0.45\textwidth]{example-image} & Description 1 & 2 \\
\includegraphics[width=0.45\textwidth]{example-image} & Description 2 & 10 \\
\caption{Gathered Data}
\label{tbl:some_data_table}\\
\end{longtable}
\end{document}
As you can see, removing the \\ also removed the small vertical whie space between the \hline and the first image. If you want to keep such a space around the images, I'd sugggest the usage of the cellspace package. In teh following MWE, I have also used the xltabular package in order to make the table as wide as the textwidth without the need to calculate the required column widths manually. I have also added the adjustbox package in order to use the valing option. Lastly, I have also moved the \caption to the top of the table as it might be a good idea to inform the reader what the table is about before starting the actual table. Especially if your table is longer than one page.
\documentclass{article}
\usepackage{xltabular}
\usepackage{graphicx}
\usepackage{array}
\usepackage{cellspace}
\setlength\cellspacetoplimit{\tabcolsep}
\setlength\cellspacebottomlimit{\tabcolsep}
\usepackage{makecell}
\begin{document}
\begin{xltabular}{\textwidth}{Sc|X|l}
\caption{Gathered Data}\label{tbl:some_data_table}\\
\makecell[l]{Thumbnail} & Description & \makecell[l]{Number of\\ Images} \\
\hline
\includegraphics[width=0.45\textwidth,valign=c]{example-image} & Description 1 & 2 \\
\includegraphics[width=0.45\textwidth,valign=c]{example-image} & Description 2 & 10 \\
\end{xltabular}
\end{document}
Personally, I'd also remove the vertical lines entirely and use horizontal lines from the booktabs package. I would also top align the contents of the cells:
\documentclass{article}
\usepackage{xltabular}
\usepackage{graphicx}
\usepackage{array}
\usepackage{cellspace}
\setlength\cellspacetoplimit{\tabcolsep}
\setlength\cellspacebottomlimit{\tabcolsep}
\usepackage{makecell}
\usepackage{booktabs}
\begin{document}
\begin{xltabular}{\textwidth}{@{}ScXl}
\caption{Gathered Data}\label{tbl:some_data_table}\\
\toprule
\multicolumn{1}{l}{Thumbnail} & Description & \makecell[l]{Number of\\ Images} \\
\midrule
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http://www.techspot.com/community/topics/dos-help-in-xp-pro.121851/
|
# DOS help in XP pro
By gbhall
Feb 8, 2009
1. MS has really got me confused ! There is no actual Dos under XP as we all well know, but the implementation of a command window gets more extensive with every issue of Windows - as witness the ROBOCOPY command in Vista !!
Now my problem is - where the heck is the PATH property specified ?
When I open a command window which is running cmd.exe in System32, there is a long path name there already, with things added by certain installed programs, like (would you believe) quicktime. In addition to which I have found there is an AUTOEXEC.NT file in SYSTEM32 and an AUTOEXEC.DOS in C:\ Neither of those has a PATH line in them.
If I open Control panel / system advanced tab and click the 'environment variables' button, there is a Path variable there, but by experiment, all it does is it ADDS to the path already present in any command windows EXCEPT a window which runs command.com instead of cmd.exe
More and more confusing - two command language processors, and at least three places where a Path can appear, one of which - the most important - I cannot even find !
I would at this point say I need both of the command processors, because there are certain 16-bit programms I like to run occasionally which will work fine under command.com, but do nothing under cmd.exe....
I would love it if someone could point me to a tutorial on 'dos in windows XP'
2. ### rickohTS Rookie
gbhall
hold down win key...(between ctrl and alt) and hit r
type cmd in the box
oops...saw that you did that....sorry.
3. ### LookinAroundTechSpot ChancellorPosts: 8,373 +167
The Windows PATH system variable (as defined via Windows system variables) should appear exactly as you define it in all command windows you open AFTER you've changed the PATH system variable. Not anything currently open. New command windows inherit CURRENT value of the Windows PATH. You can append, change, delete whatever you please to the system PATH variable
If you open a command window, remember that path is just a shell variable
=> From command prompt just type path to see your currrent Path variable
=> From command prompt, type path=yyyy to set the path variable in THAT current shell to yyyy
/* EDIT */
And don't forget the importance of enclosing things in quotes as otherwise you can get DOS command prompt very confused when it sees spaces or * or other special characters. e.g. PATH="C:\Windows\Program Files" is right, PATH=C:\Windows\Program Files will never work
4. ### gbhallTechSpot ChancellorTopic StarterPosts: 2,348 +50
What I am asking is where is the extensive PATH defined ? The one that is there already when a command shell is opened. try it, what do you get ? I get this....
PATH=C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\Program Files\QuickTime\QTSystem\;C:\Program Files\Pinnacle\Shared Files\InstantCDDVD\;C:\
where the last C:\ is the only thing in my windows path system variable.
5. ### rickohTS Rookie
gbhall
have you tried 'doskey'? as a command?
6. ### LookinAroundTechSpot ChancellorPosts: 8,373 +167
AHH.... Now i think i know what you are asking. Check out this:
When you look at your Environment Variables in Windows, note there are two sets of variables
• User variables for your logon (in upper window pane)
• System variables (in lower window pane)
Check to see if you have a PATH variable defined as each! both as a user and a system variable. The command window shell PATH is then the concatenation of both!
7. ### Bernie157TS Rookie
The path is set in the System Environment variables. You get to them by right-clicking on My Computer, then Properties (at the bottom), then the Advanced tab, then the Environment Variables button near the bottom.
To answer what I thought you were asking originally, you change directories from within the command prompt window with the CD command, e.g. CD \directory1\direcotry2 etc. You can use * as a wildcard, as in CD \dir* or CD \*ory1.
And I think you also asked: "Where is the PATH command?" Back in the days of real DOS, many commands were imbedded in the file COMMAND.COM and maybe that's the case with Windows DOS.
Bernie
8. ### gbhallTechSpot ChancellorTopic StarterPosts: 2,348 +50
Bernie, sorry to confuse, I meant the Path variable or parameter specification, not the command, which is indeed in command.com or cmd.exe
LookinAround has the correct answer to my question - there are two PATH parameters in Systen environment properties - one for user and one for 'all users' or system if you will. The latter is the one installs write to if they insist on having a path extension to work properly. Those packages were written for Win98 or thereabouts
Topic Status:
Not open for further replies.
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http://science.sciencemag.org/content/144/3623/1240
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Reports
# Circadian Leaf Movements: Persistence in Bean Plants Grown in Continuous High-Intensity Light
See allHide authors and affiliations
Science 05 Jun 1964:
Vol. 144, Issue 3623, pp. 1240-1241
DOI: 10.1126/science.144.3623.1240
## Abstract
A circadian leaf movement has been found in Phaseolus vulgaris var. Pinto that will persist under constant temperature and continuous fluorescent light. The period of leaf movement was approximately 26 hours in length, and the amplitude did not diminish for at least 4 weeks. Leaf movements were similar for plants grown in either 1100, 4950, 7700, or 10,450 lumens per square meter. This is the first clearly defined persistent circadian rhythm reported for leaves of higher plants.
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https://mapleprimes.com/users/Parham2016/replies
|
## 60 Reputation
5 years, 156 days
## @Preben Alsholm There is ...
There is a physical meaning for the relation between C1 nad B in Mechanics. I do know that 'dsolve' works for differential equations, however, the desire result could be derived by it!
## @tomleslie I meant why it was ok ...
I meant why it was ok and done in your computer but not in my laptop. How did you edit the file? For example: alpha1 was changed to alpha[1]...
Did you write the whole file again?
## @tomleslie Hello, yes it&...
Hello, yes it's ok now. It's ambiguous yet.. What have happened?
## @Kitonum Thanks. But it d...
Thanks. But it doesn't work for me.... It drove me crazy!!! It workes correctly last week. I had to get some results by the file today...
## @tomleslie Great, God ble...
Great, God bless you and happy new year.
## @tomleslie What a simple ...
What a simple solution!
Thanks.
## @_Maxim_ The integral term in F2(r)...
@_Maxim_
The integral term in F2(r) must be a value necessarily as long as those two Nu are close toghether. Indeed in the loop I want this expression " Error= (Nu_final- Nu_guess)<1e-3" to be satisfied and then the loop is going to be interrupted.
The program is correct in the first iteration for \phi= 0.06 and "initial guess Nu=3.6941" and the "final calculated Nu= 3.6942". I already know the Final Nu for \phi= 0.06!!!! But for other values of \phi I could not get any solution precisely.
## @_Maxim_ By the way, it does no...
@_Maxim_
By the way, it does not matter whether or not k is zero @ initial guess "For The First Time", the first iteration in a potential loop. As you know the initial guess for Nu is just for calculation of the integral and after that I removed it by this command: Nu:= 'Nu'.
The only important thing is this fact that the final calculated for Nu, in the end of the loop, must be equal to the initial guess.
## @_Maxim_ Hello, thanks for yo...
Hello, thanks for your consideration dear.
Yes, I want to find the Nu if the determinat is equal zero. And the problem is exactly here that the at the initial guess the determinant, k, might be any number, not necessarily zero. That is why I want to correct the Nu by replacing the initial guess with the final calculated Nu. It assumed to be difficult for me.
## @vv Thanks. But r is not equa...
Thanks. I must change the domain then! That's 3.195986267 if
0.2 <r< 1
Thanks again.
## @Markiyan Hirnyk Thanks dear,...
Thanks dear,
Yes you're right. I solve that system in Matlab (written below) and those solutions are the same.
[ 1.6759649064951345004378236436225, 0.7729562969870007822477027324705, 1.9940322524732747423780039106827]
By the way, I wrote some indices wrongly in my question!!! Now I corrected it and we can see this is true as well.
(1)
(2)
Best.
## How solve this PDE...
@tomleslie
Unfortunately I didn't write the fourth boundary conditions for you.
The four boundary conditions are in here:
V(r1,z)= V(r2,z)=0
V(r,0)= V(r,b)=0
and this point that the coordinates are
r1 < r <r2 & 0< z < b
And I want to tell you I don't have the Matlab Code I just olnly the final solution attached in the Maple primes websie.
## @Carl Love Thanks a lot Mr....
Thanks a lot Mr. Carl.
God bless you
## @tomleslie Ok, thanks. But ...
Ok, thanks. But I thought Maple could give the right answer instead of F_1(x+t)+ F_2(t-x)+ cos(x).
|
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https://mathstoshare.com/2020/03/23/why-is-the-fundamental-theorem-of-arithmetic-a-theorem/
|
# Why is the fundamental theorem of arithmetic a theorem?
The fundamental theorem of arithmetic states that every natural number can be factorized uniquely as a product of prime numbers. The word “uniquely” here means unique up to rearranging. The theorem means that if you and I take the same number $n$ and I write $n = p_1p_2\ldots p_k$ and you write $n = q_1q_2\ldots q_l$ where each $p_i$ and $q_i$ is a prime number, then in fact $k=l$ and we wrote the same prime numbers (but maybe in a different order).
Most people happily accept this theorem as self evident and believe it without proof. Indeed some people take it to be so self evident they feel it doesn’t really deserve the name “theorem” – hence the title of this blog post. In this post I want to highlight two situations where an analogous theorem fails.
## Situation One: The Even Numbers
Imagine a world where everything comes in twos. In this world nobody knows of the number one or indeed any odd number. Their counting numbers are the even numbers $\mathbb{E} = \{2,4,6,8,\ldots\}$. People in this world can add numbers and multiply numbers just like we can. They can even talk about divisibility, for example $2$ divides $8$ since $8 = 4\cdot 2$. Note that things are already getting a bit strange in this world. Since there is no number one, numbers in this world do not divide themselves.
Once people can talk about divisibility, they can talk about prime numbers. A number is prime in this world if it is not divisible by any other number. For example $2$ is prime but as we saw $8$ is not prime. Surprisingly the number $6$ is also prime in this world. This is because there are no two even numbers that multiply together to make $6$.
If a number is not prime in this world, we can reduce it to a product of primes. This is because if $n$ is not prime, then there are two number $a$ and $b$ such that $n = ab$. Since $a$ and $b$ are both smaller than $n$, we can apply the same argument and recursively write $n$ as a product of primes.
Now we can ask whether or not the fundamental theorem of arthimetic holds in this world. Namely we want to know if their is a unique way to factorize each number in this world. To get an idea we can start with some small even numbers.
• $2$ is prime.
• $4 = 2 \cdot 2$ can be factorized uniquely.
• $6$ is prime.
• $8 = 2\cdot 2 \cdot 2$ can be factorized uniquely.
• $10$ is prime.
• $12 = 2 \cdot 6$ can be factorized uniquely.
• $14$ is prime.
• $16 = 2\cdot 2 \cdot 2 \cdot 2$ can be factorized uniquely.
• $18$ is prime.
• $20 = 2 \cdot 10$ can be factorized uniquely.
Thus it seems as though there might be some hope for this theorem. It at least holds for the first handful of numbers. Unfortunately we eventually get to $36$ and we have:
$36 = 2 \cdot 18$ and $36 = 6 \cdot 6$.
Thus there are two distinct ways of writing $36$ as a product of primes in this world and thus the fundamental theorem of arithmetic does not hold.
## Situtation Two: A Number Ring
While the first example is fun and interesting, it is somewhat artificial. We are unlikely to encounter a situation where we only have the even numbers. It is however common and natural for mathematicians to be lead into certain worlds called number rings. We will see one example here and see what an effect the fundamental theorem of arithmetic can have.
Consider wanting to solve the equation $x^2+19=y^3$ where $x$ and $y$ are both integers. One way to try to solve this is by rewriting the equation as $(x+\sqrt{-19})(x-\sqrt{-19}) = y^3$. With this rewriting we have left the familiar world of the whole numbers and entered the number ring $\mathbb{Z}[\sqrt{-19}]$.
In $\mathbb{Z}[\sqrt{-19}]$ all numbers have the form $a + b \sqrt{-19}$, where $a$ and $b$ are integers. Addition of two such numbers is defined like so
$(a+b\sqrt{-19}) + (c + d \sqrt{-19}) = (a+c) + (b+d)\sqrt{-19}$.
Multiplication is define by using the distributive law and the fact that $\sqrt{-19}^2 = -19$. Thus
$(a+b\sqrt{-19})(c+d\sqrt{-19}) = (ac-19bd) + (ad+bc)\sqrt{-19}$.
Since we have multiplication we can talk about when a number in $\mathbb{Z}[\sqrt{-19}]$ divides another and hence define primes in $\mathbb{Z}[\sqrt{-19}]$. One can show that if $x^2 + 19 = y^3$, then $x+\sqrt{-19}$ and $x-\sqrt{-19}$ are coprime in $\mathbb{Z}[\sqrt{-19}]$ (see the references at the end of this post).
This means that there are no primes in $\mathbb{Z}[\sqrt{-19}]$ that divides both $x+\sqrt{-19}$ and $x-\sqrt{-19}$. If we assume that the fundamental theorem of arthimetic holds in $\mathbb{Z}[\sqrt{-19}]$, then this implies that $x+\sqrt{-19}$ must itself be a cube. This is because $(x+\sqrt{-19})(x-\sqrt{-19})=y^3$ is a cube and if two coprime numbers multiply to be a cube, then both of those coprime numbers must be cubes.
Thus we can conclude that there are integers $a$ and $b$ such that $x+\sqrt{-19} = (a+b\sqrt{-19})^3$. If we expand out this cube we can conclude that
$x+\sqrt{-19} = (a^3-57ab^2)+(3a^2b-19b^3)\sqrt{-19}$.
Thus in particular we have $1=3a^2b-19b^3=(3a^2-19b^2)b$. This implies that $b = \pm 1$ and $3a^2-19b^2=\pm 1$. Hence $b^2=1$ and $3a^2-19 = \pm 1$. Now if $3a^2 -19 =-1$, then $a^2=6$ – a contradiction. Similarly if $3a^2-19=1$, then $3a^2=20$ – another contradiction. Thus we can conclude there are no integer solutions to the equation $x^2+19=y^3$!
Unfortunately however, a bit of searching reveals that $18^2+19=343=7^3$. Thus simply assuming that that the ring $\mathbb{Z}[\sqrt{-19}]$ has unique factorization led us to incorrectly conclude that an equation had no solutions. The question of unique factorization in number rings such as $\mathbb{Z}[\sqrt{-19}]$ is a subtle and important one. Some of the flawed proofs of Fermat’s Last Theorem incorrectly assume that certain number rings have unique factorization – like we did above.
## References
The lecturer David Smyth showed us that the even integers do not have unique factorization during a lecture of the great course MATH2222.
The example of $\mathbb{Z}[\sqrt{-19}]$ failing to have unique factorization and the consequences of this was shown in a lecture for a course on algebraic number theory by James Borger. In this class we followed the (freely available) textbook “Number Rings” by P. Stevenhagen. Problem 1.4 on page 8 is the example I used in this post. By viewing the textbook you can see a complete solution to the problem.
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http://umj.imath.kiev.ua/article/?lang=en&article=9988
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2018
Том 70
№ 8
# Investigation of the solutions of a system of $n + m$ nonlineai differential equations in the vicinity of an integral manifold
Lykova O. B.
Abstract
For a system of $n + m$ equations $$\frac{dx}{dt} = X(y)x + \varepsilon X*(t, x, y),$$ $$\frac{dy}{dt} = \varepsilon Y(t, x, y),$$ where $x, X*, y, Y$ are respectively $n$ and $m$ vectors, $X — n \times n$ is the matrix, $\varepsilon$ is a small parameter, the author proves the theorem of the existence and properties of a two-dimensional local integral manifold in the neighbourhood of family of periodic solutions $$x = 0,\; y = y^0(\psi, a)$$ oi the lollowing auxiliary system $$\frac{dx}{dt} = X(y)x,$$ $$\frac{dy}{dt} = \varepsilon Y_0(x, y),$$ where $$Y_0(x, y) = \lim_{T\rightarrow 0}\int_0^T Y(t, x,y)dt.$$
Citation Example: Lykova O. B. Investigation of the solutions of a system of $n + m$ nonlineai differential equations in the vicinity of an integral manifold // Ukr. Mat. Zh. - 1964. - 16, № 1. - pp. 13-30.
Full text
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https://worldwidescience.org/topicpages/s/surface+assigning+digital.html
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#### Sample records for surface assigning digital
1. Using a digital storytelling assignment to teach public health advocacy.
Science.gov (United States)
de Castro, A B; Levesque, Salem
2018-03-01
2. The (digital) natives are restless: designing and implementing an interactive digital media assignment.
Science.gov (United States)
Voge, Catherine; Hirvela, Kari; Jarzemsky, Paula
2012-01-01
To create an opportunity for students to connect with the Quality and Safety Education for Nurses competencies and demonstrate learning via knowledge transference, the authors piloted a digital media assignment. Students worked in small groups to create an unfolding patient care scenario with embedded decision points, using presentation software. The authors discuss the assignment and its outcomes.
3. Digital Modeling Phenomenon Of Surface Ground Movement
Directory of Open Access Journals (Sweden)
Ioan Voina
2016-11-01
Full Text Available With the development of specialized software applications it was possible to approach and resolve complex problems concerning automating and process optimization for which are being used field data. Computerized representation of the shape and dimensions of the Earth requires a detailed mathematical modeling, known as "digital terrain model". The paper aims to present the digital terrain model of Vulcan mining, Hunedoara County, Romania. Modeling consists of a set of mathematical equations that define in detail the surface of Earth and has an approximate surface rigorously and mathematical, that calculated the land area. Therefore, the digital terrain model means a digital representation of the earth's surface through a mathematical model that approximates the land surface modeling, which can be used in various civil and industrial applications in. To achieve the digital terrain model of data recorded using linear and nonlinear interpolation method based on point survey which highlights the natural surface studied. Given the complexity of this work it is absolutely necessary to know in detail of all topographic elements of work area, without the actions to be undertaken to project and manipulate would not be possible. To achieve digital terrain model, within a specialized software were set appropriate parameters required to achieve this case study. After performing all steps we obtained digital terrain model of Vulcan Mine. Digital terrain model is the complex product, which has characteristics that are equivalent to the specialists that use satellite images and information stored in a digital model, this is easier to use.
4. Incorporating breeding abundance into spatial assignments on continuous surfaces.
Science.gov (United States)
Rushing, Clark S; Marra, Peter P; Studds, Colin E
2017-06-01
Determining the geographic connections between breeding and nonbreeding populations, termed migratory connectivity, is critical to advancing our understanding of the ecology and conservation of migratory species. Assignment models based on stable isotopes historically have been an important tool for studying migratory connectivity of small-bodied species, but the low resolution of these assignments has generated interest into combining isotopes with other sources in information. Abundance is one of the most appealing data sources to include in isotope-based assignments, but there are currently no statistical methods or guidelines for optimizing the contribution of stable isotopes and abundance for inferring migratory connectivity. Using known-origin stable-hydrogen isotope samples of six Neotropical migratory bird species, we rigorously assessed the performance of assignment models that differentially weight the contribution of the isotope and abundance data. For two species with adequate sample sizes, we used Pareto optimality to determine the set of models that simultaneously minimized both assignment error rate and assignment area. We then assessed the ability of the top models from these two species to improve assignments of the remaining four species compared to assignments based on isotopes alone. We show that the increased precision of models that include abundance is often offset by a large increase in assignment error. However, models that optimally weigh the abundance data relative to the isotope data can result in higher precision and, in some cases, lower error than models based on isotopes alone. The top models, however, depended on the distribution of relative breeding abundance, with patchier distributions requiring stronger downweighting of abundance, and we present general guidelines for future studies. These results confirm that breeding abundance can be an important source of information for studies investigating broad-scale movements of
5. Developing an integrated digitizing and display surface
Science.gov (United States)
Hipple, James D.; Wedding, Daniel K.; Wedding, Donald K., Sr.
1995-04-01
The development of an integrated digitizing and display surface, which utilizes touch entry and flat panel display (FPD) technology, is a significant hardware advance in the field of geographic information systems (GIS). Inherent qualities of the FPD, notably the ac gas plasma display, makes such a marriage inevitable. Large diagonal sizes, high resolution color, screen flatness, and monitor thickness are desirable features of an integrated digitizing and display surface. Recently, the GIS literature has addressed a need for such an innovation. The development of graphics displays based on sophisticated technologies include photorealistic' (or high definition) imaging at resolutions of 2048 X 2048 or greater, palates of 16.7 million colors, formats greater than 30 inches diagonal, and integrated touch entry. In this paper, there is an evaluation of FPDs and data input technologies in the development of such a product.
6. Digital Video as a Personalized Learning Assignment: A Qualitative Study of Student Authored Video Using the ICSDR Model
Science.gov (United States)
Campbell, Laurie O.; Cox, Thomas D.
2018-01-01
Students within this study followed the ICSDR (Identify, Conceptualize/Connect, Storyboard, Develop, Review/Reflect/Revise) development model to create digital video, as a personalized and active learning assignment. The participants, graduate students in education, indicated that following the ICSDR framework for student-authored video guided…
7. Empowering vocational math teachers by using digital learning material (DLM) with workplace assignments
NARCIS (Netherlands)
Zwart, D.P.; van Luit, J.E.H.; Goei, S. L.
2016-01-01
Digital Learning Material (DLM) are fast becoming a key instrument in teaching. The focus on E-learning systems with Digital Learning Material (DLM) is mostly on the medium and resources, instead of on the role of teachers. But like students, teachers also need to professionalize their digital
8. Accuracy Assessment of Different Digital Surface Models
Directory of Open Access Journals (Sweden)
Ugur Alganci
2018-03-01
Full Text Available Digital elevation models (DEMs, which can occur in the form of digital surface models (DSMs or digital terrain models (DTMs, are widely used as important geospatial information sources for various remote sensing applications, including the precise orthorectification of high-resolution satellite images, 3D spatial analyses, multi-criteria decision support systems, and deformation monitoring. The accuracy of DEMs has direct impacts on specific calculations and process chains; therefore, it is important to select the most appropriate DEM by considering the aim, accuracy requirement, and scale of each study. In this research, DSMs obtained from a variety of satellite sensors were compared to analyze their accuracy and performance. For this purpose, freely available Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER 30 m, Shuttle Radar Topography Mission (SRTM 30 m, and Advanced Land Observing Satellite (ALOS 30 m resolution DSM data were obtained. Additionally, 3 m and 1 m resolution DSMs were produced from tri-stereo images from the SPOT 6 and Pleiades high-resolution (PHR 1A satellites, respectively. Elevation reference data provided by the General Command of Mapping, the national mapping agency of Turkey—produced from 30 cm spatial resolution stereo aerial photos, with a 5 m grid spacing and ±3 m or better overall vertical accuracy at the 90% confidence interval (CI—were used to perform accuracy assessments. Gross errors and water surfaces were removed from the reference DSM. The relative accuracies of the different DSMs were tested using a different number of checkpoints determined by different methods. In the first method, 25 checkpoints were selected from bare lands to evaluate the accuracies of the DSMs on terrain surfaces. In the second method, 1000 randomly selected checkpoints were used to evaluate the methods’ accuracies for the whole study area. In addition to the control point approach, vertical cross
9. Cyber security level assignment for research reactor digital instrumentation and control system architecture using concept of defense in depth
International Nuclear Information System (INIS)
Shin, Jin Soo; Heo, Gyun Young; Son, Han Seong; Kim, Young Ki; Park, Jaek Wan
2012-01-01
Due to recent aging of the analog instrumentation of many nuclear power plants (NPPs) and research reactors, the system reliability decreases while maintenance and testing costs increase. In addition, it is difficult to find the substitutable analog equipment s due to obsolescence. Therefore, the instrumentation and control (I and C) systems have changed from analog system to digital system due to these facts. With the introduction of digital systems, research reactors are forced to care for the problem of cyber attacks because I and C systems have been digitalized using networks or communication systems. Especially, it is more issued at research reactors due to the accessibility of human resources. In the real world, an IBM researcher has been successful in controlling the software by penetrating a NPPs network in U.S. on July 2008 and acquiring the control right of nuclear facilities after one week. Moreover, the malignant code called 'stuxnet' impaired the nearly 1,000 centrifugal separators in Iran according to an IAEA report. The problem of cyber attacks highlights the important of cyber security, which should be emphasized. Defense.in.depth (DID) is a significant concept for the cyber security to work properly. DID institutes and maintains a hardy program for critical digital asset (CDA) by implementing multiple security boundaries. In this work, we assign cyber security levels to a typical digital I and C system using DID concept. This work is very useful in applying the concept of DID to nuclear industry with respect to cyber security
10. Cyber security level assignment for research reactor digital instrumentation and control system architecture using concept of defense in depth
Energy Technology Data Exchange (ETDEWEB)
Shin, Jin Soo; Heo, Gyun Young [Kyung Hee University, Seoul (Korea, Republic of); Son, Han Seong [Joongbu Univ., Chungnam (Korea, Republic of); Kim, Young Ki; Park, Jaek Wan [KAERI, Daejeon (Korea, Republic of)
2012-10-15
Due to recent aging of the analog instrumentation of many nuclear power plants (NPPs) and research reactors, the system reliability decreases while maintenance and testing costs increase. In addition, it is difficult to find the substitutable analog equipment s due to obsolescence. Therefore, the instrumentation and control (I and C) systems have changed from analog system to digital system due to these facts. With the introduction of digital systems, research reactors are forced to care for the problem of cyber attacks because I and C systems have been digitalized using networks or communication systems. Especially, it is more issued at research reactors due to the accessibility of human resources. In the real world, an IBM researcher has been successful in controlling the software by penetrating a NPPs network in U.S. on July 2008 and acquiring the control right of nuclear facilities after one week. Moreover, the malignant code called 'stuxnet' impaired the nearly 1,000 centrifugal separators in Iran according to an IAEA report. The problem of cyber attacks highlights the important of cyber security, which should be emphasized. Defense.in.depth (DID) is a significant concept for the cyber security to work properly. DID institutes and maintains a hardy program for critical digital asset (CDA) by implementing multiple security boundaries. In this work, we assign cyber security levels to a typical digital I and C system using DID concept. This work is very useful in applying the concept of DID to nuclear industry with respect to cyber security.
11. INTEGRATION OF HETEROGENOUS DIGITAL SURFACE MODELS
Directory of Open Access Journals (Sweden)
R. Boesch
2012-08-01
Full Text Available The application of extended digital surface models often reveals, that despite an acceptable global accuracy for a given dataset, the local accuracy of the model can vary in a wide range. For high resolution applications which cover the spatial extent of a whole country, this can be a major drawback. Within the Swiss National Forest Inventory (NFI, two digital surface models are available, one derived from LiDAR point data and the other from aerial images. Automatic photogrammetric image matching with ADS80 aerial infrared images with 25cm and 50cm resolution is used to generate a surface model (ADS-DSM with 1m resolution covering whole switzerland (approx. 41000 km2. The spatially corresponding LiDAR dataset has a global point density of 0.5 points per m2 and is mainly used in applications as interpolated grid with 2m resolution (LiDAR-DSM. Although both surface models seem to offer a comparable accuracy from a global view, local analysis shows significant differences. Both datasets have been acquired over several years. Concerning LiDAR-DSM, different flight patterns and inconsistent quality control result in a significantly varying point density. The image acquisition of the ADS-DSM is also stretched over several years and the model generation is hampered by clouds, varying illumination and shadow effects. Nevertheless many classification and feature extraction applications requiring high resolution data depend on the local accuracy of the used surface model, therefore precise knowledge of the local data quality is essential. The commercial photogrammetric software NGATE (part of SOCET SET generates the image based surface model (ADS-DSM and delivers also a map with figures of merit (FOM of the matching process for each calculated height pixel. The FOM-map contains matching codes like high slope, excessive shift or low correlation. For the generation of the LiDAR-DSM only first- and last-pulse data was available. Therefore only the point
12. Digital Modeling Phenomenon Of Surface Ground Movement
OpenAIRE
Ioan Voina; Maricel Palamariu; Iohan Neuner; Tudor Salagean; Dumitru Onose; Mircea Ortelecan; Anca Maria Moscovici; Mariana Calin
2016-01-01
With the development of specialized software applications it was possible to approach and resolve complex problems concerning automating and process optimization for which are being used field data. Computerized representation of the shape and dimensions of the Earth requires a detailed mathematical modeling, known as "digital terrain model". The paper aims to present the digital terrain model of Vulcan mining, Hunedoara County, Romania. Modeling consists of a set of mathematical equations th...
13. Stereological estimation of surface area from digital images
DEFF Research Database (Denmark)
Ziegel, Johanna; Kiderlen, Markus
2010-01-01
A sampling design of local stereology is combined with a method from digital stereology to yield a novel estimator of surface area based on counts of configurations observed in a digitization of an isotropic 2- dimensional slice with thickness s. As a tool, a result of the second author and J....... Rataj on infinitesimal increase of volumes of morphological transforms is refined and used. The proposed surface area estimator is asymptotically unbiased in the case of sets contained in the ball centred at the origin with radius s and in the case of balls centred at the origin with unknown radius...
14. SurfaceSlide: a multitouch digital pathology platform.
Directory of Open Access Journals (Sweden)
Yinhai Wang
Full Text Available BACKGROUND: Digital pathology provides a digital environment for the management and interpretation of pathological images and associated data. It is becoming increasing popular to use modern computer based tools and applications in pathological education, tissue based research and clinical diagnosis. Uptake of this new technology is stymied by its single user orientation and its prerequisite and cumbersome combination of mouse and keyboard for navigation and annotation. METHODOLOGY: In this study we developed SurfaceSlide, a dedicated viewing platform which enables the navigation and annotation of gigapixel digitised pathological images using fingertip touch. SurfaceSlide was developed using the Microsoft Surface, a 30 inch multitouch tabletop computing platform. SurfaceSlide users can perform direct panning and zooming operations on digitised slide images. These images are downloaded onto the Microsoft Surface platform from a remote server on-demand. Users can also draw annotations and key in texts using an on-screen virtual keyboard. We also developed a smart caching protocol which caches the surrounding regions of a field of view in multi-resolutions thus providing a smooth and vivid user experience and reducing the delay for image downloading from the internet. We compared the usability of SurfaceSlide against Aperio ImageScope and PathXL online viewer. CONCLUSION: SurfaceSlide is intuitive, fast and easy to use. SurfaceSlide represents the most direct, effective and intimate human-digital slide interaction experience. It is expected that SurfaceSlide will significantly enhance digital pathology tools and applications in education and clinical practice.
15. Merging Digital Surface Models Implementing Bayesian Approaches
Science.gov (United States)
Sadeq, H.; Drummond, J.; Li, Z.
2016-06-01
In this research different DSMs from different sources have been merged. The merging is based on a probabilistic model using a Bayesian Approach. The implemented data have been sourced from very high resolution satellite imagery sensors (e.g. WorldView-1 and Pleiades). It is deemed preferable to use a Bayesian Approach when the data obtained from the sensors are limited and it is difficult to obtain many measurements or it would be very costly, thus the problem of the lack of data can be solved by introducing a priori estimations of data. To infer the prior data, it is assumed that the roofs of the buildings are specified as smooth, and for that purpose local entropy has been implemented. In addition to the a priori estimations, GNSS RTK measurements have been collected in the field which are used as check points to assess the quality of the DSMs and to validate the merging result. The model has been applied in the West-End of Glasgow containing different kinds of buildings, such as flat roofed and hipped roofed buildings. Both quantitative and qualitative methods have been employed to validate the merged DSM. The validation results have shown that the model was successfully able to improve the quality of the DSMs and improving some characteristics such as the roof surfaces, which consequently led to better representations. In addition to that, the developed model has been compared with the well established Maximum Likelihood model and showed similar quantitative statistical results and better qualitative results. Although the proposed model has been applied on DSMs that were derived from satellite imagery, it can be applied to any other sourced DSMs.
16. MERGING DIGITAL SURFACE MODELS IMPLEMENTING BAYESIAN APPROACHES
Directory of Open Access Journals (Sweden)
2016-06-01
Full Text Available In this research different DSMs from different sources have been merged. The merging is based on a probabilistic model using a Bayesian Approach. The implemented data have been sourced from very high resolution satellite imagery sensors (e.g. WorldView-1 and Pleiades. It is deemed preferable to use a Bayesian Approach when the data obtained from the sensors are limited and it is difficult to obtain many measurements or it would be very costly, thus the problem of the lack of data can be solved by introducing a priori estimations of data. To infer the prior data, it is assumed that the roofs of the buildings are specified as smooth, and for that purpose local entropy has been implemented. In addition to the a priori estimations, GNSS RTK measurements have been collected in the field which are used as check points to assess the quality of the DSMs and to validate the merging result. The model has been applied in the West-End of Glasgow containing different kinds of buildings, such as flat roofed and hipped roofed buildings. Both quantitative and qualitative methods have been employed to validate the merged DSM. The validation results have shown that the model was successfully able to improve the quality of the DSMs and improving some characteristics such as the roof surfaces, which consequently led to better representations. In addition to that, the developed model has been compared with the well established Maximum Likelihood model and showed similar quantitative statistical results and better qualitative results. Although the proposed model has been applied on DSMs that were derived from satellite imagery, it can be applied to any other sourced DSMs.
17. STEREOLOGICAL ESTIMATION OF SURFACE AREA FROM DIGITAL IMAGES
Directory of Open Access Journals (Sweden)
Johanna Ziegel
2011-05-01
Full Text Available A sampling design of local stereology is combined with a method from digital stereology to yield a novel estimator of surface area based on counts of configurations observed in a digitization of an isotropic 2- dimensional slice with thickness s. As a tool, a result of the second author and J. Rataj on infinitesimal increase of volumes of morphological transforms is refined and used. The proposed surface area estimator is asymptotically unbiased in the case of sets contained in the ball centred at the origin with radius s and in the case of balls centred at the origin with unknown radius. For general shapes bounds for the asymptotic expected relative worst case error are given. A simulation example is discussed for surface area estimation based on 2×2×2-configurations.
18. ArcGIS Digitization of Apollo Surface Traverses
Science.gov (United States)
Petro, N. E.; Bleacher, J. E.; Gladdis, L. R.; Garry, W. B.; Lam, F.; Mest, S. C.
2012-01-01
The Apollo surface activities were documented in extraordinary detail, with every action performed by the astronauts while on the surface recorded either in photo, audio, film, or by written testimony [1]. The samples and in situ measurements the astronauts collected while on the lunar surface have shaped our understanding of the geologic history of the Moon, and the earliest history and evolution of the inner Solar System. As part of an ongoing LASERfunded effort, we are digitizing and georeferencing data from astronaut traverses and spatially associating them to available, co-registered remote sensing data. Here we introduce the products produced so far for Apollo 15, 16, and 17 missions.
19. PECULIARITIES OF ASSIGNMENT OF ROLLING BEARING MOUNTING AND PARAMETERS OF GEOMETRIC ACCURACY OF MOUNTING SURFACES OF SHAFTS AND FRAMES
Directory of Open Access Journals (Sweden)
2017-04-01
Full Text Available The standards and methods concerning assignment of rolling bearing fit with shafts and frames via example of bearing 6-208 are analyzed. We set certain differences of recommendations according to GOST 3325-85, "Rolling bearings. Tolerance zones and technical requirements to mounting surfaces of shafts and frames. Attachment" and by reference of rolling bearing manufacturers. The following factors should be taken into consideration when assigning the mounting with the tension the internal ring of the bearing with shaft and mounting with a gap in the outer ring with a housing bore. The methods of achieving accuracy of mounting surfaces of shafts and frames via form tolerance assignment: roundness tolerance, profile of longitudinal cut, cross section, cylindricity and others. It is possible to limit the bearing rings in different ways, for example appointing the cylindrical mounting surfaces and bead end surfaces the appropriate tolerances, namely: coaxiality tolerance or full radial beat of mounting surfaces, and also perpendicularity tolerance, butt beats and full butt beats of mounting end surfaces. We suggest to expand methods of achieving the accuracy of shafts and frames depending on seriation of production and production operations metrology support.
20. A NEW APPROACH OF DIGITAL BRIDGE SURFACE MODEL GENERATION
Directory of Open Access Journals (Sweden)
H. Ju
2012-07-01
Full Text Available Bridge areas present difficulties for orthophotos generation and to avoid “collapsed” bridges in the orthoimage, operator assistance is required to create the precise DBM (Digital Bridge Model, which is, subsequently, used for the orthoimage generation. In this paper, a new approach of DBM generation, based on fusing LiDAR (Light Detection And Ranging data and aerial imagery, is proposed. The no precise exterior orientation of the aerial image is required for the DBM generation. First, a coarse DBM is produced from LiDAR data. Then, a robust co-registration between LiDAR intensity and aerial image using the orientation constraint is performed. The from-coarse-to-fine hybrid co-registration approach includes LPFFT (Log-Polar Fast Fourier Transform, Harris Corners, PDF (Probability Density Function feature descriptor mean-shift matching, and RANSAC (RANdom Sample Consensus as main components. After that, bridge ROI (Region Of Interest from LiDAR data domain is projected to the aerial image domain as the ROI in the aerial image. Hough transform linear features are extracted in the aerial image ROI. For the straight bridge, the 1st order polynomial function is used; whereas, for the curved bridge, 2nd order polynomial function is used to fit those endpoints of Hough linear features. The last step is the transformation of the smooth bridge boundaries from aerial image back to LiDAR data domain and merge them with the coarse DBM. Based on our experiments, this new approach is capable of providing precise DBM which can be further merged with DTM (Digital Terrain Model derived from LiDAR data to obtain the precise DSM (Digital Surface Model. Such a precise DSM can be used to improve the orthophoto product quality.
1. A Method to Identify Flight Obstacles on Digital Surface Model
Institute of Scientific and Technical Information of China (English)
ZHAO Min; LIN Xinggang; SUN Shouyu; WANG Youzhi
2005-01-01
In modern low-altitude terrain-following guidance, a constructing method of the digital surface model (DSM) is presented in the paper to reduce the threat to flying vehicles of tall surface features for safe flight. The relationship between an isolated obstacle size and the intervals of vertical- and cross-section in the DSM model is established. The definition and classification of isolated obstacles are proposed, and a method for determining such isolated obstacles in the DSM model is given. The simulation of a typical urban district shows that when the vertical- and cross-section DSM intervals are between 3 m and 25 m, the threat to terrain-following flight at low-altitude is reduced greatly, and the amount of data required by the DSM model for monitoring in real time a flying vehicle is also smaller. Experiments show that the optimal results are for an interval of 12.5 m in the vertical- and cross-sections in the DSM model, with a 1:10 000 DSM scale grade.
2. Surface Distresses Detection of Pavement Based on Digital Image Processing
OpenAIRE
Ouyang , Aiguo; Luo , Chagen; Zhou , Chao
2010-01-01
International audience; Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and automatic detection. The applications of digital image processing in pavement crack detection, distresses classificati...
3. BUILDING DETECTION USING AERIAL IMAGES AND DIGITAL SURFACE MODELS
Directory of Open Access Journals (Sweden)
J. Mu
2017-05-01
Full Text Available In this paper a method for building detection in aerial images based on variational inference of logistic regression is proposed. It consists of three steps. In order to characterize the appearances of buildings in aerial images, an effective bag-of-Words (BoW method is applied for feature extraction in the first step. In the second step, a classifier of logistic regression is learned using these local features. The logistic regression can be trained using different methods. In this paper we adopt a fully Bayesian treatment for learning the classifier, which has a number of obvious advantages over other learning methods. Due to the presence of hyper prior in the probabilistic model of logistic regression, approximate inference methods have to be applied for prediction. In order to speed up the inference, a variational inference method based on mean field instead of stochastic approximation such as Markov Chain Monte Carlo is applied. After the prediction, a probabilistic map is obtained. In the third step, a fully connected conditional random field model is formulated and the probabilistic map is used as the data term in the model. A mean field inference is utilized in order to obtain a binary building mask. A benchmark data set consisting of aerial images and digital surfaced model (DSM released by ISPRS for 2D semantic labeling is used for performance evaluation. The results demonstrate the effectiveness of the proposed method.
4. Graphene Dendrimer-stabilized silver nanoparticles for detection of methimazole using Surface-enhanced Raman scattering with computational assignment
Science.gov (United States)
Saleh, Tawfik A.; Al-Shalalfeh, Mutasem M.; Al-Saadi, Abdulaziz A.
2016-08-01
Graphene functionalized with polyamidoamine dendrimer, decorated with silver nanoparticles (G-D-Ag), was synthesized and evaluated as a substrate with surface-enhanced Raman scattering (SERS) for methimazole (MTZ) detection. Sodium borohydride was used as a reducing agent to cultivate silver nanoparticles on the dendrimer. The obtained G-D-Ag was characterized by using UV-vis spectroscopy, scanning electron microscope (SEM), high-resolution transmission electron microscope (TEM), Fourier-transformed infrared (FT-IR) and Raman spectroscopy. The SEM image indicated the successful formation of the G-D-Ag. The behavior of MTZ on the G-D-Ag as a reliable and robust substrate was investigated by SERS, which indicated mostly a chemical interaction between G-D-Ag and MTZ. The bands of the MTZ normal spectra at 1538, 1463, 1342, 1278, 1156, 1092, 1016, 600, 525 and 410 cm-1 were enhanced due to the SERS effect. Correlations between the logarithmical scale of MTZ concentrations and SERS signal intensities were established, and a low detection limit of 1.43 × 10-12 M was successfully obtained. The density functional theory (DFT) approach was utilized to provide reliable assignment of the key Raman bands.
5. Digitization
DEFF Research Database (Denmark)
Finnemann, Niels Ole
2014-01-01
what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...
6. Reproducibility of crop surface maps extracted from Unmanned Aerial Vehicle (UAV) derived digital surface maps
KAUST Repository
Parkes, Stephen
2016-10-25
Crop height measured from UAVs fitted with commercially available RGB cameras provide an affordable alternative to retrieve field scale high resolution estimates. The study presents an assessment of between flight reproducibility of Crop Surface Maps (CSM) extracted from Digital Surface Maps (DSM) generated by Structure from Motion (SfM) algorithms. Flights were conducted over a centre pivot irrigation system covered with an alfalfa crop. An important step in calculating the absolute crop height from the UAV derived DSM is determining the height of the underlying terrain. Here we use automatic thresholding techniques applied to RGB vegetation index maps to classify vegetated and soil pixels. From interpolation of classified soil pixels, a terrain map is calculated and subtracted from the DSM. The influence of three different thresholding techniques on CSMs are investigated. Median Alfalfa crop heights determined with the different thresholding methods varied from 18cm for K means thresholding to 13cm for Otsu thresholding methods. Otsu thresholding also gave the smallest range of crop heights and K means thresholding the largest. Reproducibility of median crop heights between flight surveys was 4-6cm for all thresholding techniques. For the flight conducted later in the afternoon shadowing caused soil pixels to be classified as vegetation in key locations around the domain, leading to lower crop height estimates. The range of crop heights was similar for both flights using K means thresholding (35-36cm), local minimum thresholding depended on whether raw or normalised RGB intensities were used to calculate vegetation indices (30-35cm), while Otsu thresholding had a smaller range of heights and varied most between flights (26-30cm). This study showed that crop heights from multiple survey flights are comparable, however, they were dependent on the thresholding method applied to classify soil pixels and the time of day the flight was conducted.
7. Reproducibility of crop surface maps extracted from Unmanned Aerial Vehicle (UAV) derived digital surface maps
KAUST Repository
Parkes, Stephen; McCabe, Matthew; Al-Mashhawari, Samir K.; Rosas, Jorge
2016-01-01
Crop height measured from UAVs fitted with commercially available RGB cameras provide an affordable alternative to retrieve field scale high resolution estimates. The study presents an assessment of between flight reproducibility of Crop Surface Maps (CSM) extracted from Digital Surface Maps (DSM) generated by Structure from Motion (SfM) algorithms. Flights were conducted over a centre pivot irrigation system covered with an alfalfa crop. An important step in calculating the absolute crop height from the UAV derived DSM is determining the height of the underlying terrain. Here we use automatic thresholding techniques applied to RGB vegetation index maps to classify vegetated and soil pixels. From interpolation of classified soil pixels, a terrain map is calculated and subtracted from the DSM. The influence of three different thresholding techniques on CSMs are investigated. Median Alfalfa crop heights determined with the different thresholding methods varied from 18cm for K means thresholding to 13cm for Otsu thresholding methods. Otsu thresholding also gave the smallest range of crop heights and K means thresholding the largest. Reproducibility of median crop heights between flight surveys was 4-6cm for all thresholding techniques. For the flight conducted later in the afternoon shadowing caused soil pixels to be classified as vegetation in key locations around the domain, leading to lower crop height estimates. The range of crop heights was similar for both flights using K means thresholding (35-36cm), local minimum thresholding depended on whether raw or normalised RGB intensities were used to calculate vegetation indices (30-35cm), while Otsu thresholding had a smaller range of heights and varied most between flights (26-30cm). This study showed that crop heights from multiple survey flights are comparable, however, they were dependent on the thresholding method applied to classify soil pixels and the time of day the flight was conducted.
8. Determining Surface Infiltration Rate of Permeable Pavements with Digital Imaging
Directory of Open Access Journals (Sweden)
Caterina Valeo
2018-01-01
Full Text Available Cell phone images of pervious pavement surfaces were used to explore relationships between surface infiltration rates (SIR measured using the ASTM C1701 standard test and using a simple falling head test. A fiber-reinforced porous asphalt surface and a highly permeable material comprised of stone, rubber and a polymer binder (Porous Pave were tested. Images taken with a high-resolution cellphone camera were acquired as JPEG files and converted to gray scale images in Matlab® for analysis. The distribution of gray levels was compared to the surface infiltration rates obtained for both pavements with attention given to the mean of the distribution. Investigation into the relationships between mean SIR and parameters determined from the gray level distribution produced in the image analysis revealed that mean SIR measured in both pavements were proportional to the inverse of the mean of the distribution. The relationships produced a coefficient of determination over 85% using both the ASTM and the falling head test in the porous asphalt surface. SIR measurements determined with the ASTM method were highly correlated with the inverse mean of the distribution of gray levels in the Porous Pave material as well, producing coefficients of determination of over 90% and Kendall’s tau-b of roughly 70% for nonparametric data.
9. Comparison of digital surface displacements of maxillary dentures based on noninvasive anatomic landmarks.
Science.gov (United States)
Norvell, Nicholas G; Korioth, Tom V; Cagna, David R; Versluis, Antheunis
2018-02-08
Artificial markers called fiducials are commonly used to orient digitized surfaces for analysis. However, when these markers are tangible and placed in the region of interest, they may alter surface topography and influence data analysis. The purpose of this in vitro study was to apply a modified digital surface fitting method based on anatomic landmarks to evaluate denture accuracy and to use 2 different denture processing techniques to evaluate the method. The goal was to noninvasively measure and describe any surface differences in denture processing techniques at the intaglio and denture tooth levels. Twenty standardized maxillary complete dentures were waxed on standardized edentulous casts and processed by using acrylic resin compression (COM, n=10) and injection molding (INJ, n=10) methods. Digital scans were recorded of the anatomic surface of the cast, the intaglio and cameo surfaces of the acrylic resin dentures, and the cameo surface of the wax dentures. Three anatomic fiducials were identified on denture intaglio and cast scans and 4 on the cameo surfaces of waxed and acrylic resin denture scans. These fiducials were then used to digitally align the anatomic with the processed intaglio surfaces and the waxed with the processed cameo surfaces. Surface displacements were compared among processed dentures expressed at specific points (9 tissue landmarks and 8 tooth landmarks). The accuracy of surface displacements was assessed by changes in the number and location of anatomic fiducials. The scanning precision and the intraobserver repeatability in the selection of dental landmarks were also determined. For each landmark, the spatial (x, y, and z) mean differences between the 2 processing techniques were calculated for the intaglio and the cameo surfaces and presented on each orthogonal plane. Statistical nonparametric comparison of these means was analyzed with the Mann-Whitney U test (α=.05). Benjamini-Hochberg corrections for multiple comparisons were
10. Digital Moiré based transient interferometry and its application in optical surface measurement
Science.gov (United States)
Hao, Qun; Tan, Yifeng; Wang, Shaopu; Hu, Yao
2017-10-01
Digital Moiré based transient interferometry (DMTI) is an effective non-contact testing methods for optical surfaces. In DMTI system, only one frame of real interferogram is experimentally captured for the transient measurement of the surface under test (SUT). When combined with partial compensation interferometry (PCI), DMTI is especially appropriate for the measurement of aspheres with large apertures, large asphericity or different surface parameters. Residual wavefront is allowed in PCI, so the same partial compensator can be applied to the detection of multiple SUTs. Excessive residual wavefront aberration results in spectrum aliasing, and the dynamic range of DMTI is limited. In order to solve this problem, a method based on wavelet transform is proposed to extract phase from the fringe pattern with spectrum aliasing. Results of simulation demonstrate the validity of this method. The dynamic range of Digital Moiré technology is effectively expanded, which makes DMTI prospective in surface figure error measurement for intelligent fabrication of aspheric surfaces.
11. DIGITAL
Data.gov (United States)
Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...
12. Quantitative Evaluation of Surface Color of Tomato Fruits Cultivated in Remote Farm Using Digital Camera Images
Science.gov (United States)
Hashimoto, Atsushi; Suehara, Ken-Ichiro; Kameoka, Takaharu
To measure the quantitative surface color information of agricultural products with the ambient information during cultivation, a color calibration method for digital camera images and a remote monitoring system of color imaging using the Web were developed. Single-lens reflex and web digital cameras were used for the image acquisitions. The tomato images through the post-ripening process were taken by the digital camera in both the standard image acquisition system and in the field conditions from the morning to evening. Several kinds of images were acquired with the standard RGB color chart set up just behind the tomato fruit on a black matte, and a color calibration was carried out. The influence of the sunlight could be experimentally eliminated, and the calibrated color information consistently agreed with the standard ones acquired in the system through the post-ripening process. Furthermore, the surface color change of the tomato on the tree in a greenhouse was remotely monitored during maturation using the digital cameras equipped with the Field Server. The acquired digital color images were sent from the Farm Station to the BIFE Laboratory of Mie University via VPN. The time behavior of the tomato surface color change during the maturing process could be measured using the color parameter calculated based on the obtained and calibrated color images along with the ambient atmospheric record. This study is a very important step in developing the surface color analysis for both the simple and rapid evaluation of the crop vigor in the field and to construct an ambient and networked remote monitoring system for food security, precision agriculture, and agricultural research.
13. Influence of the surface roughness of coated and uncoated papers on the digital print mottle
Directory of Open Access Journals (Sweden)
Ivana Jurič
2014-07-01
Full Text Available Many factors influence the occurrence of print mottle in prints. In printing process three main components are involved: printing press, substrate and toner. They can be considered as separate components, but in most cases their interaction influences the quality of the print. The goal of this work was to examine the influence of surface roughness of different types of paper (coated and uncoated on print mottle of electrophotographic digital prints. We set up a hypothesis that print mottle will be more apparent on rougher surfaces. In the experimental part we printed four different substrates with different surface properties on electrophotographic printing press. Morphology of the papers surface was analysed using atomic force microscopy (AFM from which surface properties were calculated. For print mottle characterization Gray level co-occurrence matrix (GLCM method was used. Based on the measurements and results we can conclude, contrary to the initial hypothesis, that uncoated papers with rougher surfaces produce smaller print mottle values.
14. Precise measurement of cat patellofemoral joint surface geometry with multistation digital photogrammetry.
Science.gov (United States)
Ronsky, J L; Boyd, S K; Lichti, D D; Chapman, M A; Salkauskas, K
1999-04-01
Three-dimensional joint models are important tools for investigating mechanisms related to normal and pathological joints. Often these models necessitate accurate three-dimensional joint surface geometric data so that reliable model results can be obtained; however, in models based on small joints, this is often problematic due to limitations of the present techniques. These limitations include insufficient measurement precision the requirement of contact for the measurement process, and lack of entire joint description. This study presents a new non-contact method for precise determination of entire joint surfaces using multistation digital photogrammetry (MDPG) and is demonstrated by determining the cartilage and subchondral bone surfaces of the cat patellofemoral (PF) joint. The digital camera-lens setup was precisely calibrated using 16 photographs arranged to achieve highly convergent geometry to estimate interior and distortion parameters of the camera-lens setup. Subsequently, six photographs of each joint surface were then acquired for surface measurement. The digital images were directly imported to a computer and newly introduced semi-automatic computer algorithms were used to precisely determine the image coordinates. Finally, a rigorous mathematical procedure named the bundle adjustment was used to determine the three-dimensional coordinates of the joint surfaces and to estimate the precision of the coordinates. These estimations were validated by comparing the MDPG measurements of a cylinder and plane to an analytical model. The joint surfaces were successfully measured using the MDPG method with mean precision estimates in the least favorable coordinate direction being 10.3 microns for subchondral bone and 17.9 microns for cartilage. The difference in measurement precision for bone and cartilage primarily reflects differences in the translucent properties of the surfaces.
15. Macro-carriers of plastic deformation of steel surface layers detected by digital image correlation
Energy Technology Data Exchange (ETDEWEB)
Kopanitsa, D. G., E-mail: [email protected]; Ustinov, A. M., E-mail: [email protected] [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); Potekaev, A. I., E-mail: [email protected] [National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Klopotov, A. A., E-mail: [email protected] [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Kopanitsa, G. D., E-mail: [email protected] [National Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)
2016-01-15
This paper presents a study of characteristics of an evolution of deformation fields in surface layers of medium-carbon low-alloy specimens under compression. The experiments were performed on the “Universal Testing Machine 4500” using a digital stereoscopic image processing system Vic-3D. A transition between stages is reflected as deformation redistribution on the near-surface layers. Electronic microscopy shows that the structure of the steel is a mixture of pearlite and ferrite grains. A proportion of pearlite is 40% and ferrite is 60%.
16. Automatic centroid detection and surface measurement with a digital Shack–Hartmann wavefront sensor
International Nuclear Information System (INIS)
Yin, Xiaoming; Zhao, Liping; Li, Xiang; Fang, Zhongping
2010-01-01
With the breakthrough of manufacturing technologies, the measurement of surface profiles is becoming a big issue. A Shack–Hartmann wavefront sensor (SHWS) provides a promising technology for non-contact surface measurement with a number of advantages over interferometry. The SHWS splits the incident wavefront into many subsections and transfers the distorted wavefront detection into the centroid measurement. So the accuracy of the centroid measurement determines the accuracy of the SHWS. In this paper, we have presented a new centroid measurement algorithm based on an adaptive thresholding and dynamic windowing method by utilizing image-processing techniques. Based on this centroid detection method, we have developed a digital SHWS system which can automatically detect centroids of focal spots, reconstruct the wavefront and measure the 3D profile of the surface. The system has been tested with various simulated and real surfaces such as flat surfaces, spherical and aspherical surfaces as well as deformable surfaces. The experimental results demonstrate that the system has good accuracy, repeatability and immunity to optical misalignment. The system is also suitable for on-line applications of surface measurement
17. Massachusetts Bay - Internal wave packets digitized from SAR imagery and intersected with a bathymetrically derived slope surface
Data.gov (United States)
National Oceanic and Atmospheric Administration, Department of Commerce — This feature class contains internal wave packets digitized from SAR imagery and intersected with a bathymetrically derived slope surface for Massachusetts Bay. The...
18. Digital mineral logging system
International Nuclear Information System (INIS)
West, J.B.
1980-01-01
A digital mineral logging system acquires data from a mineral logging tool passing through a borehole and transmits the data uphole to an electronic digital signal processor. A predetermined combination of sensors, including a deviometer, is located in a logging tool for the acquisition of the desired data as the logging tool is raised from the borehole. Sensor data in analog format is converted in the logging tool to a digital format and periodically batch transmitted to the surface at a predetermined sampling rate. An identification code is provided for each mineral logging tool, and the code is transmitted to the surface along with the sensor data. The self-identifying tool code is transmitted to the digital signal processor to identify the code against a stored list of the range of numbers assigned to that type of tool. The data is transmitted up the d-c power lines of the tool by a frequency shift key transmission technique. At the surface, a frequency shift key demodulation unit transmits the decoupled data to an asynchronous receiver interfaced to the electronic digital signal processor. During a recording phase, the signals from the logging tool are read by the electronic digital signal processor and stored for later processing. During a calculating phase, the stored data is processed by the digital signal processor and the results are outputted to a printer or plotter, or both
19. Digital map and situation surface: a team-oriented multidisplay workspace for network enabled situation analysis
Science.gov (United States)
Peinsipp-Byma, E.; Geisler, Jürgen; Bader, Thomas
2009-05-01
System concepts for network enabled image-based ISR (intelligence, surveillance, reconnaissance) is the major mission of Fraunhofer IITB's applied research in the area of defence and security solutions. For the TechDemo08 as part of the NATO CNAD POW Defence against terrorism Fraunhofer IITB advanced a new multi display concept to handle the shear amount and high complexity of ISR data acquired by networked, distributed surveillance systems with the objective to support the generation of a common situation picture. Amount and Complexity of ISR data demands an innovative man-machine interface concept for humans to deal with it. The IITB's concept is the Digital Map & Situation Surface. This concept offers to the user a coherent multi display environment combining a horizontal surface for the situation overview from the bird's eye view, an attached vertical display for collateral information and so-called foveatablets as personalized magic lenses in order to obtain high resolved and role-specific information about a focused areaof- interest and to interact with it. In the context of TechDemo08 the Digital Map & Situation Surface served as workspace for team-based situation visualization and analysis. Multiple sea- and landside surveillance components were connected to the system.
20. Digital detection system of surface defects for large aperture optical elements
International Nuclear Information System (INIS)
Fan Yong; Chen Niannian; Gao Lingling; Jia Yuan; Wang Junbo; Cheng Xiaofeng
2009-01-01
Based on the light defect images against the dark background in a scattering imaging system, a digital detection system of surface defects for large aperture optical elements has been presented. In the system, the image is segmented by a multi-area self-adaptive threshold segmentation method, then a pixel labeling method based on replacing arrays is adopted to extract defect features quickly, and at last the defects are classified through back-propagation neural networks. Experiment results show that the system can achieve real-time detection and classification. (authors)
1. Skin surface and sub-surface strain and deformation imaging using optical coherence tomography and digital image correlation
Science.gov (United States)
Hu, X.; Maiti, R.; Liu, X.; Gerhardt, L. C.; Lee, Z. S.; Byers, R.; Franklin, S. E.; Lewis, R.; Matcher, S. J.; Carré, M. J.
2016-03-01
Bio-mechanical properties of the human skin deformed by external forces at difference skin/material interfaces attract much attention in medical research. For instance, such properties are important design factors when one designs a healthcare device, i.e., the device might be applied directly at skin/device interfaces. In this paper, we investigated the bio-mechanical properties, i.e., surface strain, morphological changes of the skin layers, etc., of the human finger-pad and forearm skin as a function of applied pressure by utilizing two non-invasive techniques, i.e., optical coherence tomography (OCT) and digital image correlation (DIC). Skin deformation results of the human finger-pad and forearm skin were obtained while pressed against a transparent optical glass plate under the action of 0.5-24 N force and stretching naturally from 90° flexion to 180° full extension respectively. The obtained OCT images showed the deformation results beneath the skin surface, however, DIC images gave overall information of strain at the surface.
2. Taking advantage of reduced droplet-surface interaction to optimize transport of bioanalytes in digital microfluidics.
Science.gov (United States)
Freire, Sergio L S; Thorne, Nathaniel; Wutkowski, Michael; Dao, Selina
2014-11-10
Digital microfluidics (DMF), a technique for manipulation of droplets, is a promising alternative for the development of "lab-on-a-chip" platforms. Often, droplet motion relies on the wetting of a surface, directly associated with the application of an electric field; surface interactions, however, make motion dependent on droplet contents, limiting the breadth of applications of the technique. Some alternatives have been presented to minimize this dependence. However, they rely on the addition of extra chemical species to the droplet or its surroundings, which could potentially interact with droplet moieties. Addressing this challenge, our group recently developed Field-DW devices to allow the transport of cells and proteins in DMF, without extra additives. Here, the protocol for device fabrication and operation is provided, including the electronic interface for motion control. We also continue the studies with the devices, showing that multicellular, relatively large, model organisms can also be transported, arguably unaffected by the electric fields required for device operation.
3. Detecting Plagiarism in MS Access Assignments
Science.gov (United States)
Singh, Anil
2013-01-01
Assurance of individual effort from students in computer-based assignments is a challenge. Due to digitization, students can easily use a copy of their friend's work and submit it as their own. Plagiarism in assignments puts students who cheat at par with those who work honestly and this compromises the learning evaluation process. Using a…
4. Error rate of automated calculation for wound surface area using a digital photography.
Science.gov (United States)
Yang, S; Park, J; Lee, H; Lee, J B; Lee, B U; Oh, B H
2018-02-01
Although measuring would size using digital photography is a quick and simple method to evaluate the skin wound, the possible compatibility of it has not been fully validated. To investigate the error rate of our newly developed wound surface area calculation using digital photography. Using a smartphone and a digital single lens reflex (DSLR) camera, four photographs of various sized wounds (diameter: 0.5-3.5 cm) were taken from the facial skin model in company with color patches. The quantitative values of wound areas were automatically calculated. The relative error (RE) of this method with regard to wound sizes and types of camera was analyzed. RE of individual calculated area was from 0.0329% (DSLR, diameter 1.0 cm) to 23.7166% (smartphone, diameter 2.0 cm). In spite of the correction of lens curvature, smartphone has significantly higher error rate than DSLR camera (3.9431±2.9772 vs 8.1303±4.8236). However, in cases of wound diameter below than 3 cm, REs of average values of four photographs were below than 5%. In addition, there was no difference in the average value of wound area taken by smartphone and DSLR camera in those cases. For the follow-up of small skin defect (diameter: <3 cm), our newly developed automated wound area calculation method is able to be applied to the plenty of photographs, and the average values of them are a relatively useful index of wound healing with acceptable error rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
5. A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation
Directory of Open Access Journals (Sweden)
Khoo Sze-Wei
2016-09-01
Full Text Available Among the full-field optical measurement methods, the Digital Image Correlation (DIC is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.
6. COMPARISON OF DIGITAL SURFACE MODELS FOR SNOW DEPTH MAPPING WITH UAV AND AERIAL CAMERAS
Directory of Open Access Journals (Sweden)
R. Boesch
2016-06-01
Full Text Available Photogrammetric workflows for aerial images have improved over the last years in a typically black-box fashion. Most parameters for building dense point cloud are either excessive or not explained and often the progress between software releases is poorly documented. On the other hand, development of better camera sensors and positional accuracy of image acquisition is significant by comparing product specifications. This study shows, that hardware evolutions over the last years have a much stronger impact on height measurements than photogrammetric software releases. Snow height measurements with airborne sensors like the ADS100 and UAV-based DSLR cameras can achieve accuracies close to GSD * 2 in comparison with ground-based GNSS reference measurements. Using a custom notch filter on the UAV camera sensor during image acquisition does not yield better height accuracies. UAV based digital surface models are very robust. Different workflow parameter variations for ADS100 and UAV camera workflows seem to have only random effects.
7. Micro patterned surfaces: an effective tool for long term digital holographic microscopy cell imaging
Science.gov (United States)
Mues, Sarah; Lilge, Inga; Schönherr, Holger; Kemper, Björn; Schnekenburger, Jürgen
2017-02-01
The major problem of Digital Holographic Microscopy (DHM) long term live cell imaging is that over time most of the tracked cells move out of the image area and other ones move in. Therefore, most of the cells are lost for the evaluation of individual cellular processes. Here, we present an effective solution for this crucial problem of long-term microscopic live cell analysis. We have generated functionalized slides containing areas of 250 μm per 200 μm. These micropatterned biointerfaces consist of passivating polyaclrylamide brushes (PAAm). Inner areas are backfilled with octadecanthiol (ODT), which allows cell attachment. The fouling properties of these surfaces are highly controllable and therefore the defined areas designed for the size our microscopic image areas were effective in keeping all cells inside the rectangles over the selected imaging period.
8. Digitally Milled Metal Framework for Fixed Complete Denture with Metal Occlusal Surfaces: A Design Concept.
Science.gov (United States)
Implant-supported fixed complete dentures, often referred to as hybrid prostheses, have been associated with high implant survival rates but also with a high incidence of mechanical prosthetic complications. The most frequent of these complications have been fracture and wear of the veneering material. The proposed design concept incorporates the occlusal surfaces of the posterior teeth as part of a digital milled metal framework by designing the posterior first molars in full contour as part of the framework. The framework can be designed, scanned, and milled from a titanium blank using a milling machine. Acrylic resin teeth can then be placed on the framework by conventional protocol. The metal occlusal surfaces of the titanium-countered molars will be at centric occlusion. It is hypothesized that metal occlusal surfaces in the posterior region may reduce occlusal wear in these types of prostheses. When the proposed design protocol is followed, the connection between the metal frame and the cantilever part of the prosthesis is reinforced, which may lead to fewer fractures of the metal framework.
9. FULLY AUTOMATED GENERATION OF ACCURATE DIGITAL SURFACE MODELS WITH SUB-METER RESOLUTION FROM SATELLITE IMAGERY
Directory of Open Access Journals (Sweden)
J. Wohlfeil
2012-07-01
Full Text Available Modern pixel-wise image matching algorithms like Semi-Global Matching (SGM are able to compute high resolution digital surface models from airborne and spaceborne stereo imagery. Although image matching itself can be performed automatically, there are prerequisites, like high geometric accuracy, which are essential for ensuring the high quality of resulting surface models. Especially for line cameras, these prerequisites currently require laborious manual interaction using standard tools, which is a growing problem due to continually increasing demand for such surface models. The tedious work includes partly or fully manual selection of tie- and/or ground control points for ensuring the required accuracy of the relative orientation of images for stereo matching. It also includes masking of large water areas that seriously reduce the quality of the results. Furthermore, a good estimate of the depth range is required, since accurate estimates can seriously reduce the processing time for stereo matching. In this paper an approach is presented that allows performing all these steps fully automated. It includes very robust and precise tie point selection, enabling the accurate calculation of the images’ relative orientation via bundle adjustment. It is also shown how water masking and elevation range estimation can be performed automatically on the base of freely available SRTM data. Extensive tests with a large number of different satellite images from QuickBird and WorldView are presented as proof of the robustness and reliability of the proposed method.
10. Automated analysis of art object surfaces using time-averaged digital speckle pattern interferometry
Science.gov (United States)
Lukomski, Michal; Krzemien, Leszek
2013-05-01
Technical development and practical evaluation of a laboratory built, out-of-plane digital speckle pattern interferometer (DSPI) are reported. The instrument was used for non-invasive, non-contact detection and characterization of early-stage damage, like fracturing and layer separation, of painted objects of art. A fully automated algorithm was developed for recording and analysis of vibrating objects utilizing continuous-wave laser light. The algorithm uses direct, numerical fitting or Hilbert transformation for an independent, quantitative evaluation of the Bessel function at every point of the investigated surface. The procedure does not require phase modulation and thus can be implemented within any, even the simplest, DSPI apparatus. The proposed deformation analysis is fast and computationally inexpensive. Diagnosis of physical state of the surface of a panel painting attributed to Nicolaus Haberschrack (a late-mediaeval painter active in Krakow) from the collection of the National Museum in Krakow is presented as an example of an in situ application of the developed methodology. It has allowed the effectiveness of the deformation analysis to be evaluated for the surface of a real painting (heterogeneous colour and texture) in a conservation studio where vibration level was considerably higher than in the laboratory. It has been established that the methodology, which offers automatic analysis of the interferometric fringe patterns, has a considerable potential to facilitate and render more precise the condition surveys of works of art.
11. Accuracy Assessment of Digital Surface Models from Unmanned Aerial Vehicles’ Imagery on Glaciers
Directory of Open Access Journals (Sweden)
2017-02-01
Full Text Available The use of Unmanned Aerial Vehicles (UAV for photogrammetric surveying has recently gained enormous popularity. Images taken from UAVs are used for generating Digital Surface Models (DSMs and orthorectified images. In the glaciological context, these can serve for quantifying ice volume change or glacier motion. This study focuses on the accuracy of UAV-derived DSMs. In particular, we analyze the influence of the number and disposition of Ground Control Points (GCPs needed for georeferencing the derived products. A total of 1321 different DSMs were generated from eight surveys distributed on three glaciers in the Swiss Alps during winter, summer and autumn. The vertical and horizontal accuracy was assessed by cross-validation with thousands of validation points measured with a Global Positioning System. Our results show that the accuracy increases asymptotically with increasing number of GCPs until a certain density of GCPs is reached. We call this the optimal GCP density. The results indicate that DSMs built with this optimal GCP density have a vertical (horizontal accuracy ranging between 0.10 and 0.25 m (0.03 and 0.09 m across all datasets. In addition, the impact of the GCP distribution on the DSM accuracy was investigated. The local accuracy of a DSM decreases when increasing the distance to the closest GCP, typically at a rate of 0.09 m per 100-m distance. The impact of the glacier’s surface texture (ice or snow was also addressed. The results show that besides cases with a surface covered by fresh snow, the surface texture does not significantly influence the DSM accuracy.
12. "Scratch"ing below the Surface: Mathematics through an Alternative Digital Lens?
Science.gov (United States)
Calder, Nigel; Taylor, Merilyn
2010-01-01
A key element in the examination of how students process mathematics through digital technologies is considering the ways that digital pedagogical media might influence the learning process. How might students' understanding emerge through engagement in a digital-learning environment? Interactive software that has cross-curricula implications and…
13. Automatic Seamline Network Generation for Urban Orthophoto Mosaicking with the Use of a Digital Surface Model
Directory of Open Access Journals (Sweden)
Qi Chen
2014-12-01
Full Text Available Intelligent seamline selection for image mosaicking is an area of active research in the fields of massive data processing, computer vision, photogrammetry and remote sensing. In mosaicking applications for digital orthophoto maps (DOMs, the visual transition in mosaics is mainly caused by differences in positioning accuracy, image tone and relief displacement of high ground objects between overlapping DOMs. Among these three factors, relief displacement, which prevents the seamless mosaicking of images, is relatively more difficult to address. To minimize visual discontinuities, many optimization algorithms have been studied for the automatic selection of seamlines to avoid high ground objects. Thus, a new automatic seamline selection algorithm using a digital surface model (DSM is proposed. The main idea of this algorithm is to guide a seamline toward a low area on the basis of the elevation information in a DSM. Given that the elevation of a DSM is not completely synchronous with a DOM, a new model, called the orthoimage elevation synchronous model (OESM, is derived and introduced. OESM can accurately reflect the elevation information for each DOM unit. Through the morphological processing of the OESM data in the overlapping area, an initial path network is obtained for seamline selection. Subsequently, a cost function is defined on the basis of several measurements, and Dijkstra’s algorithm is adopted to determine the least-cost path from the initial network. Finally, the proposed algorithm is employed for automatic seamline network construction; the effective mosaic polygon of each image is determined, and a seamless mosaic is generated. The experiments with three different datasets indicate that the proposed method meets the requirements for seamline network construction. In comparative trials, the generated seamlines pass through fewer ground objects with low time consumption.
14. Persistent and automatic intraoperative 3D digitization of surfaces under dynamic magnifications of an operating microscope.
Science.gov (United States)
Kumar, Ankur N; Miga, Michael I; Pheiffer, Thomas S; Chambless, Lola B; Thompson, Reid C; Dawant, Benoit M
2015-01-01
errors (surface-to-surface distance) in the 0.28-0.81 mm range on the phantom object and in the 0.54-1.35 mm range on 4 clinical cases. The digitization accuracy of the presented stereovision methods indicate that the operating microscope can be used to deliver the persistent intraoperative input required by computational biomechanical models to update the patient's preoperative images and facilitate active surgical guidance. Copyright © 2014 Elsevier B.V. All rights reserved.
15. Persistent and automatic intraoperative 3D digitization of surfaces under dynamic magnifications of an operating microscope
Science.gov (United States)
Kumar, Ankur N.; Miga, Michael I.; Pheiffer, Thomas S.; Chambless, Lola B.; Thompson, Reid C.; Dawant, Benoit M.
2014-01-01
errors (surface-to-surface distance) in the 0.28-0.81mm range on the phantom object and in the 0.54-1.35mm range on 4 clinical cases. The digitization accuracy of the presented stereovision methods indicate that the operating microscope can be used to deliver the persistent intraoperative input required by computational biomechanical models to update the patient’s preoperative images and facilitate active surgical guidance. PMID:25189364
16. Optical Injection Locking of Vertical Cavity Surface-Emitting Lasers: Digital and Analog Applications
Science.gov (United States)
Parekh, Devang
With the rise of mobile (cellphones, tablets, notebooks, etc.) and broadband wireline communications (Fiber to the Home), there are increasing demands being placed on transmitters for moving data from device to device and around the world. Digital and analog fiber-optic communications have been the key technology to meet this challenge, ushering in ubiquitous Internet and cable TV over the past 20 years. At the physical layer, high-volume low-cost manufacturing of semiconductor optoelectronic devices has played an integral role in allowing for deployment of high-speed communication links. In particular, vertical cavity surface emitting lasers (VCSEL) have revolutionized short reach communications and are poised to enter more markets due to their low cost, small size, and performance. However, VCSELs have disadvantages such as limited modulation performance and large frequency chirp which limits fiber transmission speed and distance, key parameters for many fiber-optic communication systems. Optical injection locking is one method to overcome these limitations without re-engineering the VCSEL at the device level. By locking the frequency and phase of the VCSEL by the direct injection of light from another laser oscillator, improved device performance is achieved in a post-fabrication method. In this dissertation, optical injection locking of VCSELs is investigated from an applications perspective. Optical injection locking of VCSELs can be used as a pathway to reduce complexity, cost, and size of both digital and analog fiber-optic communications. On the digital front, reduction of frequency chirp via bit pattern inversion for large-signal modulation is experimentally demonstrated showing up to 10 times reduction in frequency chirp and over 90 times increase in fiber transmission distance. Based on these results, a new reflection-based interferometric model for optical injection locking was established to explain this phenomenon. On the analog side, the resonance
17. Object based classification of high resolution data in urban areas considering digital surface models
OpenAIRE
Oczipka, Martin Eckhard
2010-01-01
Over the last couple of years more and more analogue airborne cameras were replaced by digital cameras. Digitally recorded image data have significant advantages to film based data. Digital aerial photographs have a much better radiometric resolution. Image information can be acquired in shaded areas too. This information is essential for a stable and continuous classification, because no data or unclassified areas should be as small as possible. Considering this technological progress, on...
18. Develop of ceramic effects: surface finishes, through digital inject technology; Desarrollo de efectos ceramicos como acabados superficiales, mediante tecnologia de inyeccion digital
Energy Technology Data Exchange (ETDEWEB)
NONE
2012-07-01
Ferro Spain SA has tackled the practical viability of tile surfaces decoration by means of applying layers of reduced thickness by means of the use of digital injection technology by ink jet and, specifically, relating to effects and superficial finishes different from colouring. It has been studied several mechanisms which allow to get those effects and the influence of the main variables. It has also been assessed the obtained results dealing with the current regulations as in the case of non-slip effect. (Author)
19. Digital fringe projection for hand surface coordinate variation analysis caused by osteoarthritis
Science.gov (United States)
Nor Haimi, Wan Mokhdzani Wan; Hau Tan, Cheek; Retnasamy, Vithyacharan; Vairavan, Rajendaran; Sauli, Zaliman; Roshidah Yusof, Nor; Hambali, Nor Azura Malini Ahmad; Aziz, Muhammad Hafiz Ab; Bakhit, Ahmad Syahir Ahmad
2017-11-01
Hand osteoarthritis is one of the most common forms of arthritis which impact millions of people worldwide. The disabling problem occurs when the protective cartilage on the boundaries of bones wear off over time. Currently, in order to identify hand osteoarthritis, special instruments namely X-ray scanning and MRI are used for the detection but it also has its limitations such as radiation exposure and can be quite costly. In this work, an optical metrology system based on digital fringe projection which comprises of an LCD projector, CCD camera and a personal computer has been developed to anticipate abnormal growth or deformation on the joints of the hand which are common symptoms of osteoarthritis. The main concept of this optical metrology system is to apply structured light as imaging source for surface change detection. The imaging source utilizes fringe patterns generated by C++ programming and is shifted by 3 phase shifts based on the 3 steps 2 shifts method. Phase wrapping technique and analysis were applied in order to detect the deformation of live subjects. The result has demonstrated a successful method of hand deformation detection based on the pixel tracking differences of a normal and deformed state.
20. A Hierarchical Building Segmentation in Digital Surface Models for 3D Reconstruction
Directory of Open Access Journals (Sweden)
Yiming Yan
2017-01-01
Full Text Available In this study, a hierarchical method for segmenting buildings in a digital surface model (DSM, which is used in a novel framework for 3D reconstruction, is proposed. Most 3D reconstructions of buildings are model-based. However, the limitations of these methods are overreliance on completeness of the offline-constructed models of buildings, and the completeness is not easily guaranteed since in modern cities buildings can be of a variety of types. Therefore, a model-free framework using high precision DSM and texture-images buildings was introduced. There are two key problems with this framework. The first one is how to accurately extract the buildings from the DSM. Most segmentation methods are limited by either the terrain factors or the difficult choice of parameter-settings. A level-set method are employed to roughly find the building regions in the DSM, and then a recently proposed ‘occlusions of random textures model’ are used to enhance the local segmentation of the buildings. The second problem is how to generate the facades of buildings. Synergizing with the corresponding texture-images, we propose a roof-contour guided interpolation of building facades. The 3D reconstruction results achieved by airborne-like images and satellites are compared. Experiments show that the segmentation method has good performance, and 3D reconstruction is easily performed by our framework, and better visualization results can be obtained by airborne-like images, which can be further replaced by UAV images.
1. VERTICAL ACCURACY ASSESSMENT OF ZY-3 DIGITAL SURFACE MODEL USING ICESAT/GLAS LASER ALTIMETER DATA
Directory of Open Access Journals (Sweden)
G. Li
2017-05-01
Full Text Available The Ziyuan-3 (ZY-3 satellite, as the first civilian high resolution surveying and mapping satellite in China, has a very important role in national 1 : 50,000 stereo mapping project. High accuracy digital surface Model (DSMs can be generated from the three line-array images of ZY-3, and ZY-3 DSMs of China can be produced without using any ground control points (GCPs by selecting SRTM (Shuttle Radar Topography Mission and ICESat/GLAS (Ice, Cloud, and land Elevation Satellite, Geo-science Laser Altimeter System as the datum reference in the Satellite Surveying and Mapping Application Center, which is the key institute that manages and distributes ZY-3 products. To conduct the vertical accuracy evaluation of ZY-3 DSMs of China, three representative regions were chosen and the results were compared to ICESat/GLAS data. The experimental results demonstrated that the root mean square error (RMSE elevation accuracy of the ZY-3 DSMs was better than 5.0 m, and it even reached to less than 2.5 m in the second region of eastern China. While this work presents preliminary results, it is an important reference for expanding the application of ZY-3 satellite imagery to widespread regions. And the satellite laser altimetry data can be used as referenced data for wide-area DSM evaluation.
2. Analysis of overdeepened valleys using the digital elevation model of the bedrock surface of Northern Switzerland
Energy Technology Data Exchange (ETDEWEB)
Jordan, P.
2010-11-15
Based on surface and borehole information, together with pre-existing regional and local interpretations, a 7,150 square kilometre Raster Digital Elevation Model (DEM) of the bedrock surface of northern Switzerland was constructed using a 25 m cell size. This model represents a further important step in the understanding of Quaternary sediment distribution and is open to a broad field of application and analysis, including hydrogeological, geotechnical and geophysical studies as well as research in the field of Pleistocene landscape evolution. An analysis of the overdeepened valleys in the whole model area and, more specifically in the Reuss area, shows that, in most cases, overdeepening is restricted to the areas covered by the Last Glaciation Maximum (LGM). However, at various locations relatively narrow overdeepened valleys outreach the tongue basins and the LGM ice shield limits. Therefore, an earlier and further-reaching glacial event has probably contributed significantly to the overdeepening of these valleys. No significant overdeepening has been identified downstream of Boettstein (Aare) and Kaiserstuhl (Rhine), although the ice extended considerably further downstream, at least during the most extensive glaciation. Except for the bedrock between Brugg and Boettstein, no overdeepened valleys are found significantly north of the outcrop of Mesozoic limestone of the Folded and Tabular Jura. A detailed analysis of the Reuss area shows that the Lake and Suhre valleys are separated from the Emmen-Gisikon Reuss valley basin by a significant bedrock barrier. The individual bedrock valleys are divided into several sub-basins, indicating a multiphase evolution of the valleys. Some of the swells or barriers separating the sub-basins coincide with known late LGM retreat stages. In the Suhre valley, an old fluvial valley floor with restricted overdeepened sections is documented. (author)
3. Airborne hyperspectral observations of surface and cloud directional reflectivity using a commercial digital camera
Directory of Open Access Journals (Sweden)
A. Ehrlich
2012-04-01
Full Text Available Spectral radiance measurements by a digital single-lens reflex camera were used to derive the directional reflectivity of clouds and different surfaces in the Arctic. The camera has been calibrated radiometrically and spectrally to provide accurate radiance measurements with high angular resolution. A comparison with spectral radiance measurements with the Spectral Modular Airborne Radiation measurement sysTem (SMART-Albedometer showed an agreement within the uncertainties of both instruments (6% for both. The directional reflectivity in terms of the hemispherical directional reflectance factor (HDRF was obtained for sea ice, ice-free ocean and clouds. The sea ice, with an albedo of ρ = 0.96 (at 530 nm wavelength, showed an almost isotropic HDRF, while sun glint was observed for the ocean HDRF (ρ = 0.12. For the cloud observations with ρ = 0.62, the cloudbow – a backscatter feature typically for scattering by liquid water droplets – was covered by the camera. For measurements above heterogeneous stratocumulus clouds, the required number of images to obtain a mean HDRF that clearly exhibits the cloudbow has been estimated at about 50 images (10 min flight time. A representation of the HDRF as a function of the scattering angle only reduces the image number to about 10 (2 min flight time.
The measured cloud and ocean HDRF have been compared to radiative transfer simulations. The ocean HDRF simulated with the observed surface wind speed of 9 m s−1 agreed best with the measurements. For the cloud HDRF, the best agreement was obtained by a broad and weak cloudbow simulated with a cloud droplet effective radius of Reff = 4 μm. This value agrees with the particle sizes derived from in situ measurements and retrieved from the spectral radiance of the SMART-Albedometer.
4. Planialtimetric Accuracy Evaluation of Digital Surface Model (dsm) and Digital Terrain Model (dtm) Obtained from Aerial Survey with LIDAR
Science.gov (United States)
Cruz, C. B. M.; Barros, R. S.; Rabaco, L. M. L.
2012-07-01
It's noticed a significant increase in the development of orbital and airborne sensors that enable the extraction of three-dimensional data. Consequently, it's important the increment of studies about the quality of altimetric values derived from these sensors to verify if the improvements implemented in the acquisition of data may influence the results. In this context, as part of a larger project that aims to evaluate the accuracy of various sensors, this work aims to analysis the planialtimetric accuracy of DSM and DTM generated from an aerial survey with LIDAR, using as reference for the planimetric analysis of the orthophotos obtained. The project was developed for an area of São Sebastião city, located in the basin of the North Coast of São Paulo state. The area's relief is very steep, with a predominance of dense forest vegetation, typical of the Atlantic Forest. All points have been established in the field, with the use of GNSS of one frequency (L1) through static relative positioning, acquiring a minimum of 1,500 epochs, for a distance less than 20 km to the base. In this work it's considered the Brazilian standard specifications for classification of cartographic bases (PEC). The Brazilian company responsible for the aerial survey (LACTEC) gave the following products for analysis: point clouds in raw format (x, y, z) using orthometric heights; point clouds (first and last pulse) for each range of flight to verify systematic errors; DTM uniformly spaced, filtering small natural obstacles, buildings and vegetation, in Geotiff format; DSM also uniformly spaced, in Geotiff format; and the mosaic of georeferenced digital images. The analysis realized on products from the LIDAR indicated their adoption to the scales 1:2,000 (Class A for the orthophotos and Class B for the DTM) and 1:5,000 (class C for the DSM). There were no indications of trends in the results. The average error was 0.01 m. It's important that new areas with different topographic
5. Digital dental surface registration with laser scanner for orthodontics set-up planning
Science.gov (United States)
Alcaniz-Raya, Mariano L.; Albalat, Salvador E.; Grau Colomer, Vincente; Monserrat, Carlos A.
1997-05-01
We present an optical measuring system based on laser structured light suitable for its diary use in orthodontics clinics that fit four main requirements: (1) to avoid use of stone models, (2) to automatically discriminate geometric points belonging to teeth and gum, (3) to automatically calculate diagnostic parameters used by orthodontists, (4) to make use of low cost and easy to use technology for future commercial use. Proposed technique is based in the use of hydrocolloids mould used by orthodontists for stone model obtention. These mould of the inside of patient's mouth are composed of very fluent materials like alginate or hydrocolloids that reveal fine details of dental anatomy. Alginate mould are both very easy to obtain and very low costly. Once captured, alginate moulds are digitized by mean of a newly developed and patented 3D dental scanner. Developed scanner is based in the optical triangulation method based in the projection of a laser line on the alginate mould surface. Line deformation gives uncalibrated shape information. Relative linear movements of the mould with respect to the sensor head gives more sections thus obtaining a full 3D uncalibrated dentition model. Developed device makes use of redundant CCD in the sensor head and servocontrolled linear axis for mould movement. Last step is calibration to get a real and precise X, Y, Z image. All the process is done automatically. The scanner has been specially adapted for 3D dental anatomy capturing in order to fulfill specific requirements such as: scanning time, accuracy, security and correct acquisition of 'hidden points' in alginate mould. Measurement realized on phantoms with known geometry quite similar to dental anatomy present errors less than 0,1 mm. Scanning of global dental anatomy is 2 minutes, and generation of 3D graphics of dental cast takes approximately 30 seconds in a Pentium-based PC.
6. Exploring Digital Surface Models from Nine Different Sensors for Forest Monitoring and Change Detection
Directory of Open Access Journals (Sweden)
Jiaojiao Tian
2017-03-01
Full Text Available Digital surface models (DSMs derived from spaceborne and airborne sensors enable the monitoring of the vertical structures for forests in large areas. Nevertheless, due to the lack of an objective performance assessment for this task, it is difficult to select the most appropriate data source for DSM generation. In order to fill this gap, this paper performs change detection analysis including forest decrease and tree growth. The accuracy of the DSMs is evaluated by comparison with measured tree heights from inventory plots (field data. In addition, the DSMs are compared with LiDAR data to perform a pixel-wise quality assessment. DSMs from four different satellite stereo sensors (ALOS/PRISM, Cartosat-1, RapidEye and WorldView-2, one satellite InSAR sensor (TanDEM-X, two aerial stereo camera systems (HRSC and UltraCam and two airborne laser scanning datasets with different point densities are adopted for the comparison. The case study is a complex central European temperate forest close to Traunstein in Bavaria, Germany. As a major experimental result, the quality of the DSM is found to be robust to variations in image resolution, especially when the forest density is high. The forest decrease results confirm that besides aerial photogrammetry data, very high resolution satellite data, such as WorldView-2, can deliver results with comparable quality as the ones derived from LiDAR, followed by TanDEM-X and Cartosat DSMs. The quality of the DSMs derived from ALOS and Rapid-Eye data is lower, but the main changes are still correctly highlighted. Moreover, the vertical tree growth and their relationship with tree height are analyzed. The major tree height in the study site is between 15 and 30 m and the periodic annual increments (PAIs are in the range of 0.30–0.50 m.
7. Detection of hidden stationary deformations of vibrating surfaces by use of time-averaged digital holographic interferometry.
Science.gov (United States)
Demoli, Nazif; Vukicevic, Dalibor
2004-10-15
A method of detecting displacements of a surface from its steady-state position to its equilibrium position while it is vibrating has been developed by use of time-average digital holographic interferometry. This method permits extraction of such a hidden deformation by creating two separated systems of interferogram fringes: one corresponding to a time-varying resonantly oscillating optical phase, the other to the stationary phase modification. A mathematical description of the method and illustrative results of experimental verification are presented.
8. UAV based 3D digital surface model to estimate paleolandscape in high mountainous environment
Science.gov (United States)
Mészáros, János; Árvai, Mátyás; Kohán, Balázs; Deák, Márton; Nagy, Balázs
2016-04-01
Our method to present current state of a peat bog was focused on the possible use of a UAV-system and later Structure-from-motion algorithms as processing technique. The peat bog site is located on the Vinderel Plateau, Farcǎu Massif, Maramures Mountains (Romania). The peat bog (1530 m a.s.l., N47°54'11", E24°26'37") lies below Rugasu ridge (c. 1820 m a.s.l.) and the locality serves as a conservation area for fallen down coniferous trees. Peat deposits were formed in a landslide concavity on the western slope of Farcǎu Massif. Nowadays the site is surrounded by a completely deforested landscape, and Farcǎu Massif lies above the depressed treeline. The peat bog has an extraordinary geomorphological situation, because a gully reached the bog and drained the water. In the recent past sedimentological and dendrochronological researches have been initiated. However, an accurate 3D digital surface model also needed for a complex paleoenvironmental research. Last autumn the bog and its surroundings were finally surveyed by a multirotor UAV developed in-house based on an open-source flight management unit and its firmware. During this survey a lightweight action camera (mainly to decrease payload weight) was used to take aerial photographs. While our quadcopter is capable to fly automatically on a predefined flight route, several over- and sidelapping flight lines were generated prior to the actual survey on the ground using a control software running on a notebook. Despite those precautions, limited number of batteries and severe weather affected our final flights, resulting a reduced surveyed area around peat bog. Later, during the processing we looked for a reliable tool which powerful enough to process more than 500 photos taken during flights. After testing several software Agisoft PhotoScan was used to create 3D point cloud and mesh about bog and its environment. Due to large number of photographs PhotoScan had to be configured for network processing to get
9. Plagiarism-Proofing Assignments
Science.gov (United States)
Johnson, Doug
2004-01-01
Mr. Johnson has discovered that the higher the level of student engagement and creativity, the lower the probability of plagiarism. For teachers who would like to see such desirable results, he describes the characteristics of assignments that are most likely to produce them. Two scenarios of types of assignments that avoid plagiarism are…
10. The surfacing of past assessment strategies within interdisciplinary teams when encountering an open-ended assignment in an undergraduate sustainability course
Science.gov (United States)
Hartman, K.; Dzulkifli, D. D. B.; Moynihan, M. A.; Salman, R.; Goodkin, N.
2017-12-01
11. Double resonance capacitance spectroscopy (DORCAS): A new experimental technique for assignment of X-ray absorption peaks to surface sites of semiconductor
CERN Document Server
Ishii, M
2003-01-01
As a new microspectroscopy for semiconductor surface analysis using an X-ray beam, double resonance capacitance spectroscopy (DORCAS) is proposed. For a microscopic X-ray absorption measurement, a local capacitance change owing to X-ray induced emission of localized electrons is detected by a microprobe. The applied bias voltage V sub b dependence of the capacitance also provides information on the surface density of state. The resonance of the Fermi energy with a surface level by V sub b control makes possible the selection of the observable surface site in the X-ray absorption measurements, i.e. site-specific spectroscopy. The double resonance of the surface site selection (V sub b resonance) and the resonant X-ray absorption of the selected site (photon energy h nu resonance) enhances the capacitance signal. The DORCAS measurement of the GaAs surface shows correlation peaks at h nu=10.402 keV and V sub b =-0.4 V and h nu=10.429 keV and V sub b =+0.1 V, indicating that these resonant X-ray absorption peaks ...
12. RADARGRAMMETRIC DIGITAL SURFACE MODELS GENERATION FROM TERRASAR-X IMAGERY: CASE STUDIES, PROBLEMS AND POTENTIALITIES
Directory of Open Access Journals (Sweden)
P. Capaldo
2012-07-01
Full Text Available The interest for the radargrammetric approach to Digital Surface Models (DSMs generation has been growing in last years thanks to the availability of very high resolution imagery acquired by new SAR (Synthetic Aperture Radar sensors, as COSMO-SkyMed, Radarsat-2 and TerraSAR-X, which are able to supply imagery up to 1 m ground resolution. DSMs radargrammetric generation approach consists of two basic steps, as for the standard photogrammetry applied to optical imagery: the imagery (at least a stereo pair orientation and the image matching for the generation of the points cloud. The steps of the radargrammetric DSMs generation have been implemented into SISAR (Software per Immagini Satellitari ad Alta Risoluzione, a scientific software developed at Geodesy and Geomatics Institute of the University of Rome “La Sapienza”. Moreover, starting from the radargrammetric orientation model, a tool for the Rational Polynomial Coefficients (RPCs for SAR images have been implemented. The possibility to generate RPCs, re-parametrizing a rigorous orientation model through a standardized set of coefficients which can be managed by a Rational Polynomial Coefficients (RPFs model (similarly to optical high resolution imagery sounds of particular interest since, at present, the most part of SAR imagery (except from Radarsat-2 is not supplied with RPCs, although the corresponding RPFs model is available in several commercial software. In particular the RPCs model has been used in the matching process and in the stereo restitution for the DSMs generation, with the advantage of shorter computational time. This paper discusses the application and the results of the implemented algorithm for radargrammetric DSMs generation from TerraSAR-X SpotLight imagery, acquired in Spotlight mode over Trento (Northern Italy. Urban and extra-urban (forested, cultivated areas were considered in two different tiles, and a final overall accuracy ranging from 4.5 to 6 meters was
13. Fair Package Assignment
Science.gov (United States)
Lahaie, Sébastien; Parkes, David C.
We consider the problem of fair allocation in the package assignment model, where a set of indivisible items, held by single seller, must be efficiently allocated to agents with quasi-linear utilities. A fair assignment is one that is efficient and envy-free. We consider a model where bidders have superadditive valuations, meaning that items are pure complements. Our central result is that core outcomes are fair and even coalition-fair over this domain, while fair distributions may not even exist for general valuations. Of relevance to auction design, we also establish that the core is equivalent to the set of anonymous-price competitive equilibria, and that superadditive valuations are a maximal domain that guarantees the existence of anonymous-price competitive equilibrium. Our results are analogs of core equivalence results for linear prices in the standard assignment model, and for nonlinear, non-anonymous prices in the package assignment model with general valuations.
14. My Favorite Assignment.
Science.gov (United States)
ABCA Bulletin, 1983
1983-01-01
Describes three assignments for enticing business communication students to undertake library research: an analysis of a Fortune 500 company, a career choice report, and a report on an organization that offers potential employment. (AEA)
15. Historical WBAN ID Assignments
Data.gov (United States)
National Oceanic and Atmospheric Administration, Department of Commerce — 4"x6" index cards represent the first written assignments of Weather Bureau Army Navy (WBAN) station identifier numbers by the National Climatic Data Center....
16. Dynamic Sequence Assignment.
Science.gov (United States)
1983-12-01
D-136 548 DYNAMIIC SEQUENCE ASSIGNMENT(U) ADVANCED INFORMATION AND 1/2 DECISION SYSTEMS MOUNTAIN YIELW CA C A 0 REILLY ET AL. UNCLSSIIED DEC 83 AI/DS...I ADVANCED INFORMATION & DECISION SYSTEMS Mountain View. CA 94040 84 u ,53 V,..’. Unclassified _____ SCURITY CLASSIFICATION OF THIS PAGE REPORT...reviews some important heuristic algorithms developed for fas- ter solution of the sequence assignment problem. 3.1. DINAMIC MOGRAMUNIG FORMULATION FOR
17. Digital processing of SEM images for the assessment of evaluation indexes of cleaning interventions on Pentelic marble surfaces
International Nuclear Information System (INIS)
Moropoulou, A.; Delegou, E.T.; Vlahakis, V.; Karaviti, E.
2007-01-01
In this work, digital processing of scanning-electron-microscopy images utilized to assess cleaning interventions applied on the Pentelic marble surfaces of the National Archaeological Museum and National Library in Athens, Greece. Beside mineralogical and chemical characterization that took place by scanning-electron-microscopy with Energy Dispersive X-ray Spectroscopy, the image-analysis program EDGE was applied for estimating three evaluation indexes of the marble micro-structure. The EDGE program was developed by the U.S. Geological Survey for the evaluation of cleaning interventions applied on Philadelphia City Hall. This computer program analyzes scanning-electron-microscopy images of stone specimens cut in cross-section for measuring the fractal dimension of the exposed surfaces, the stone near-surface fracture density, the shape factor (a surface roughness factor) and the friability index which represents the physico-chemical and physico-mechanical stability of the stone surface. The results indicated that the evaluation of the marble surface micro-structure before and after cleaning is achieved by the suggested indexes, while the performance of cleaning interventions on the marble surfaces can be assessed
18. Surface Water & Surface Drainage
Data.gov (United States)
Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...
19. FLEET ASSIGNMENT MODELLING
Directory of Open Access Journals (Sweden)
2016-01-01
Full Text Available The article is devoted to the airline scheduling process and methods of its modeling. This article describes the main stages of airline scheduling process (scheduling, fleet assignment, revenue management, operations, their features and interactions. The main part of scheduling process is fleet assignment. The optimal solution of the fleet assignment problem enables airlines to increase their incomes up to 3 % due to quality improving of connections and execution of the planned number of flights operated by less number of aircraft than usual or planned earlier. Fleet assignment of scheduling process is examined and Conventional Leg-Based Fleet Assignment Model is analyzed. Finally strong and weak aspects of the model (SWOT are released and applied. The article gives a critical analysis of FAM model, with the purpose of identi- fying possible options and constraints of its use (for example, in cases of short-term and long-term planning, changing the schedule or replacing the aircraft, as well as possible ways to improve the model.
20. Digital assessment of preliminary impression accuracy for edentulous jaws: Comparisons of 3-dimensional surfaces between study and working casts.
Science.gov (United States)
Matsuda, Takashi; Goto, Takaharu; Kurahashi, Kosuke; Kashiwabara, Toshiya; Watanabe, Megumi; Tomotake, Yoritoki; Nagao, Kan; Ichikawa, Tetsuo
2016-07-01
The aim of this study was to compare 3-dimensional surfaces of study and working casts for edentulous jaws and to evaluate the accuracy of preliminary impressions with a view to the future application of digital dentistry for edentulous jaws. Forty edentulous volunteers were serially recruited. Nine dentists took preliminary and final impressions in a routine clinical work-up. The study and working casts were digitized using a dental 3-dimensional scanner. The two surface images were superimposed through a least-square algorithm using imaging software and compared qualitatively. Furthermore, the surface of each jaw was divided into 6 sections, and the difference between the 2 images was quantitatively evaluated. Overall inspection showed that the difference around residual ridges was small and that around borders were large. The mean differences in the upper and lower jaws were 0.26mm and 0.45mm, respectively. The maximum values of the differences showed that the upward change mainly occurred in the anterior residual ridge, and the downward change mainly in the posterior border seal, and the labial and buccal vestibules, whereas every border of final impression was shortened in the lower jaw. The accuracy in all areas except the border, which forms the foundation, was estimated to be less than 0.25mm. Using digital technology, we here showed the overall and sectional accuracy of the preliminary impression for edentulous jaws. In our clinic, preliminary impressions have been made using an alginate material while ensuring that the requisite impression area was covered. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.
1. Effect of uncertainty in Digital Surface Models on the boundary of inundated areas
Science.gov (United States)
Nalbantis, I.; Papageorgaki, I.; Sioras, P.; Ioannidis, Ch.
2012-04-01
The planning, design and operation of flood damage reduction works or non-structural measures require the construction of maps that indicate zones to be potentially inundated during floods. Referring to floods due to heavy rainfall, the common procedure for flood mapping consists of the following five computational steps: (1) Frequency analysis of extreme rainfall; (2) construction of design hyetographs for various return periods; (3) construction of the related direct runoff hydrographs; (4) routing of these hydrographs through the hydrographic network; (5) mapping of the inundated area that corresponds to the temporally maximum depth for each location in the flood plain. Steps 3 through 5 require the use of spatial information which can be easily obtained from a Digital Surface Model (DSM). The DSM contains grid-based elevations of the ground or overlying objects that influence the propagation of flood waves. In this work, the SCS-CN method is used in step 3 in combination with a synthetic Unit Hydrograph based on the SCS dimensionless Unit Hydrograph. In step 4, the full one-dimensional Saint Venant equations for non-uniform unsteady flow on fixed bed are used, which are numerically solved. The impact of uncertainty in the DSM on the inundated area boundary is investigated. For this the Monte Carlo simulation method is employed to produce a large number of erroneous DSMs through introducing errors in elevation with a standard deviation equal to σ. These DSMs are then used for delineating potentially flooded areas. The standard deviation of the distance (from the riverbed axis) of the boundary of these areas, herein denoted as σF, is used as the measure of the resulting uncertainty. The link between σ and σF is examined for a spectrum of large return periods (100 to 10000). A computer experiment was set up based on data from two drainage basins. The first basin is located in East Attica and is drained by a branch of the Erasinos Torrent named the South
2. Use of digital image analysis combined with fractal theory to determine particle morphology and surface texture of quartz sands
Directory of Open Access Journals (Sweden)
Georgia S. Araujo
2017-12-01
Full Text Available The particle morphology and surface texture play a major role in influencing mechanical and hydraulic behaviors of sandy soils. This paper presents the use of digital image analysis combined with fractal theory as a tool to quantify the particle morphology and surface texture of two types of quartz sands widely used in the region of Vitória, Espírito Santo, southeast of Brazil. The two investigated sands are sampled from different locations. The purpose of this paper is to present a simple, straightforward, reliable and reproducible methodology that can identify representative sandy soil texture parameters. The test results of the soil samples of the two sands separated by sieving into six size fractions are presented and discussed. The main advantages of the adopted methodology are its simplicity, reliability of the results, and relatively low cost. The results show that sands from the coastal spit (BS have a greater degree of roundness and a smoother surface texture than river sands (RS. The values obtained in the test are statistically analyzed, and again it is confirmed that the BS sand has a slightly greater degree of sphericity than that of the RS sand. Moreover, the RS sand with rough surface texture has larger specific surface area values than the similar BS sand, which agree with the obtained roughness fractal dimensions. The consistent experimental results demonstrate that image analysis combined with fractal theory is an accurate and efficient method to quantify the differences in particle morphology and surface texture of quartz sands.
3. Digital asset management.
Science.gov (United States)
Humphrey, Clinton D; Tollefson, Travis T; Kriet, J David
2010-05-01
Facial plastic surgeons are accumulating massive digital image databases with the evolution of photodocumentation and widespread adoption of digital photography. Managing and maximizing the utility of these vast data repositories, or digital asset management (DAM), is a persistent challenge. Developing a DAM workflow that incorporates a file naming algorithm and metadata assignment will increase the utility of a surgeon's digital images. Copyright 2010 Elsevier Inc. All rights reserved.
NARCIS (Netherlands)
Dominguez-Martinez, S.
2009-01-01
An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching
5. The Translucent Cadaver: An Evaluation of the Use of Full Body Digital X-Ray Images and Drawings in Surface Anatomy Education
Science.gov (United States)
Kotze, Sanet Henriet; Mole, Calvin Gerald; Greyling, Linda Magdalena
2012-01-01
It has been noted by staff at the Faculty of Health Sciences, Stellenbosch University that medical students neglect the study of surface anatomy during dissection. This study reports on the novel use of Lodox[R] Statscan[R] images in anatomical education, particularly the teaching of surface anatomy. Full body digital X-ray images (Lodox Statscan)…
6. An autonomous surface discontinuity detection and quantification method by digital image correlation and phase congruency
Science.gov (United States)
Cinar, A. F.; Barhli, S. M.; Hollis, D.; Flansbjer, M.; Tomlinson, R. A.; Marrow, T. J.; Mostafavi, M.
2017-09-01
Digital image correlation has been routinely used to measure full-field displacements in many areas of solid mechanics, including fracture mechanics. Accurate segmentation of the crack path is needed to study its interaction with the microstructure and stress fields, and studies of crack behaviour, such as the effect of closure or residual stress in fatigue, require data on its opening displacement. Such information can be obtained from any digital image correlation analysis of cracked components, but it collection by manual methods is quite onerous, particularly for massive amounts of data. We introduce the novel application of Phase Congruency to detect and quantify cracks and their opening. Unlike other crack detection techniques, Phase Congruency does not rely on adjustable threshold values that require user interaction, and so allows large datasets to be treated autonomously. The accuracy of the Phase Congruency based algorithm in detecting cracks is evaluated and compared with conventional methods such as Heaviside function fitting. As Phase Congruency is a displacement-based method, it does not suffer from the noise intensification to which gradient-based methods (e.g. strain thresholding) are susceptible. Its application is demonstrated to experimental data for cracks in quasi-brittle (Granitic rock) and ductile (Aluminium alloy) materials.
7. Generalized configurations of the reconstruction and hologram surface in digital holography
International Nuclear Information System (INIS)
Frere, C.
1988-01-01
Approximations are introduced for calculating the complex amplitude in holography, so that diffraction effects from curved lines and from the hologram surface are negligible. These effects are estimated. In the one-dimensional case, the calculation was made by the steady-phase method, with a weaker condition than the Fresnel condition. The one-dimensional transparency is exemplarily on straight, sinusoidal and elliptic lines while plane and cylindrical surfaces are chosen for the hologram surface. In the two-dimensional case, a numerical calculation is carried out using the fast Fourier transformation algorithm, and with a condition similar to the Fresnel condition. Compared with the transparency distribution, this method yields slightly disturbed reconstruction distributions. Inclined planes and cylindrical surfaces were chosen as hologram surfaces. The calculated complex amplitudes were encoded and materialized in a computer-supported hologram. (orig./DG) [de
8. Personnel dose assignment practices
International Nuclear Information System (INIS)
Fix, J.J.
1993-04-01
Implementation of DOE N 5480.6 Radiological Control Manual Article 511(3) requirements, to minimize the assignment of personnel dosimeters, should be done only under a broader context ensuring that capabilities are in place to monitor and record personnel exposure both for compliance and for potential litigation. As noted in NCRP Report No. 114, personnel dosimetry programs are conducted to meet four major objectives: radiation safety program control and evaluation; regulatory compliance; epidemiological research; and litigation. A change to Article 511(3) is proposed that would require that minimizing the assignment of personnel dosimeters take place only following full evaluation of overall capabilities (e.g., access control, area dosimetry, etc.) to meet the NCRP objectives
9. Scaffolding students’ assignments
DEFF Research Database (Denmark)
Slot, Marie Falkesgaard
2013-01-01
This article discusses scaffolding in typical student assignments in mother tongue learning materials in upper secondary education in Denmark and the United Kingdom. It has been determined that assignments do not have sufficient scaffolding end features to help pupils understand concepts and build...... objects. The article presents the results of empirical research on tasks given in Danish and British learning materials. This work is based on a further development of my PhD thesis: “Learning materials in the subject of Danish” (Slot 2010). The main focus is how cognitive models (and subsidiary explicit...... learning goals) can help students structure their argumentative and communica-tive learning processes, and how various multimodal representations can give more open-ended learning possibilities for collaboration. The article presents a short introduction of the skills for 21st century learning and defines...
OpenAIRE
Dominguez-Martinez, S.
2009-01-01
An important task of a manager is to motivate her subordinates. One way in which a manager can give incentives to junior employees is through the assignment of tasks. How a manager allocates tasks in an organization, provides information to the junior employees about his ability. Without coaching from a manager, the junior employee only has information about his past performance. Based on his past performance, a talented junior who has performed a difficult task sometimes decides to leave the...
11. Digital image processing: Cylindrical surface plane development of CAREM fuel pellets
International Nuclear Information System (INIS)
Caccavelli, J; Cativa Tolosa, S; Gommes, C
2012-01-01
As part of the development of fuel pellets (FPs) for nuclear reactor CAREM-25, is necessary to systematize the analysis of the mechanical integrity of the FPs that is now done manually by a human operator. Following specifications and standards of reference for this purpose, the FPs should be inspected visually for detecting material discontinuities in the FPs surfaces to minimize any deterioration, loss of material and excessive breakage during operation and load of fuel bars. The material discontinuities are classified into two defects: surface cracks and chips. For each of these surface defects exist acceptance criteria that determine if the fuel pellet (FP) as a whole is accepted or rejected. One criteria for surface cracks is that they do not exceed one third (1/3) of the circumferential surface of the FP. The FP has cylindrical shape, so some of these acceptance criteria make difficult to analyze the FP in a single photographic image. Depending on the axial rotation of the FP, the crack could not be entirely visualized on the picture frame. Even a single crack that appears in different parts of the FP rotated images may appear to be different cracks in the FP when it is actually one. For this reason it is necessary, for the automatic detection and measurement of surface defects, obtain the circumferential surface of the FP into a single image in order to decide the acceptance or reject of the FP. As the FP shape is cylindrical, it is possible to obtain the flat development of the cylindrical surface (surface unrolling) of the FPs into a single image combining the image set of the axial rotation of the FP. In this work, we expose the procedure to implement the flat development of the cylindrical surface (surface unrolling). Starting from a photographic image of the FP surface, which represents the projection of a cylinder in the plane, we obtain three-dimensional information of each point on the cylindrical surface of the FP (3D-mapping). Then, we can
12. Surface enhancement Raman scattering of tautomeric thiobarbituric acid. Natural bond orbitals and B3LYP/6-311+G (d, p) assignments of the Fourier Infrared and Fourier Raman Spectra.
Science.gov (United States)
Soto, C A Téllez; Ramos, J M; Costa Junior, A C; Vieira, Laís S; Rangel, João L; Raniero, L; Fávero, Priscila P; Lemma, Tibebe; Ondar, Grisset F; Versiane, Otavio; Martin, A A
2013-10-01
Surface enhancement Raman scattering (SERS) of two tautomer of thiobarbituric acid was obtained using silver and gold nanoparticles. Large band enhancement in the region of the ν(C=S), ν(C=C), δ(CH2), and δ(CNH) vibrational modes was found. Natural bond analysis of the tautomer species revealed expressive values of charge transfer, principally from lone pair electron orbitals of the S, N, and O atoms. Complete vibrational assignment was done for the two tautomers using the B3LYP/6-311+G (d, p) procedure, band deconvolution analysis, and from a rigorous interpretation of the normal modes matrix. The calculated spectra agree well with the experimental ones. Copyright © 2013 Elsevier B.V. All rights reserved.
13. Digital printing
Science.gov (United States)
Sobotka, Werner K.
1997-02-01
Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.
14. Digital photography and transparency-based methods for measuring wound surface area.
Science.gov (United States)
Bhedi, Amul; Saxena, Atul K; Gadani, Ravi; Patel, Ritesh
2013-04-01
To compare and determine a credible method of measurement of wound surface area by linear, transparency, and photographic methods for monitoring progress of wound healing accurately and ascertaining whether these methods are significantly different. From April 2005 to December 2006, 40 patients (30 men, 5 women, 5 children) admitted to the surgical ward of Shree Sayaji General Hospital, Baroda, had clean as well as infected wound following trauma, debridement, pressure sore, venous ulcer, and incision and drainage. Wound surface areas were measured by these three methods (linear, transparency, and photographic methods) simultaneously on alternate days. The linear method is statistically and significantly different from transparency and photographic methods (P value transparency and photographic methods (P value >0.05). Photographic and transparency methods provided measurements of wound surface area with equivalent result and there was no statistically significant difference between these two methods.
15. Single-exposure two-dimensional superresolution in digital holography using a vertical cavity surface-emitting laser source array.
Science.gov (United States)
Granero, Luis; Zalevsky, Zeev; Micó, Vicente
2011-04-01
We present a new implementation capable of producing two-dimensional (2D) superresolution (SR) imaging in a single exposure by aperture synthesis in digital lensless Fourier holography when using angular multiplexing provided by a vertical cavity surface-emitting laser source array. The system performs the recording in a single CCD snapshot of a multiplexed hologram coming from the incoherent addition of multiple subholograms, where each contains information about a different 2D spatial frequency band of the object's spectrum. Thus, a set of nonoverlapping bandpass images of the input object can be recovered by Fourier transformation (FT) of the multiplexed hologram. The SR is obtained by coherent addition of the information contained in each bandpass image while generating an enlarged synthetic aperture. Experimental results demonstrate improvement in resolution and image quality.
16. Surface relief and refractive index gratings patterned in chalcogenide glasses and studied by off-axis digital holography.
Science.gov (United States)
Cazac, V; Meshalkin, A; Achimova, E; Abashkin, V; Katkovnik, V; Shevkunov, I; Claus, D; Pedrini, G
2018-01-20
Surface relief gratings and refractive index gratings are formed by direct holographic recording in amorphous chalcogenide nanomultilayer structures As 2 S 3 -Se and thin films As 2 S 3 . The evolution of the grating parameters, such as the modulation of refractive index and relief depth in dependence of the holographic exposure, is investigated. Off-axis digital holographic microscopy is applied for the measurement of the photoinduced phase gratings. For the high-accuracy reconstruction of the wavefront (amplitude and phase) transmitted by the fabricated gratings, we used a computational technique based on the sparse modeling of phase and amplitude. Both topography and refractive index maps of recorded gratings are revealed. Their separated contribution in diffraction efficiency is estimated.
17. Potential solar radiation and land cover contributions to digital climate surface modeling
Science.gov (United States)
Puig, Pol; Batalla, Meritxell; Pesquer, Lluís; Ninyerola, Miquel
2016-04-01
18. An interactive local flattening operator to support digital investigations on artwork surfaces.
Science.gov (United States)
Pietroni, Nico; Massimiliano, Corsini; Cignoni, Paolo; Scopigno, Roberto
2011-12-01
Analyzing either high-frequency shape detail or any other 2D fields (scalar or vector) embedded over a 3D geometry is a complex task, since detaching the detail from the overall shape can be tricky. An alternative approach is to move to the 2D space, resolving shape reasoning to easier image processing techniques. In this paper we propose a novel framework for the analysis of 2D information distributed over 3D geometry, based on a locally smooth parametrization technique that allows us to treat local 3D data in terms of image content. The proposed approach has been implemented as a sketch-based system that allows to design with a few gestures a set of (possibly overlapping) parameterizations of rectangular portions of the surface. We demonstrate that, due to the locality of the parametrization, the distortion is under an acceptable threshold, while discontinuities can be avoided since the parametrized geometry is always homeomorphic to a disk. We show the effectiveness of the proposed technique to solve specific Cultural Heritage (CH) tasks: the analysis of chisel marks over the surface of a unfinished sculpture and the local comparison of multiple photographs mapped over the surface of an artwork. For this very difficult task, we believe that our framework and the corresponding tool are the first steps toward a computer-based shape reasoning system, able to support CH scholars with a medium they are more used to. © 2011 IEEE
19. Local digital control of power electronic converters in a dc microgrid based on a-priori derivation of switching surfaces
Science.gov (United States)
Banerjee, Bibaswan
In power electronic basedmicrogrids, the computational requirements needed to implement an optimized online control strategy can be prohibitive. The work presented in this dissertation proposes a generalized method of derivation of geometric manifolds in a dc microgrid that is based on the a-priori computation of the optimal reactions and trajectories for classes of events in a dc microgrid. The proposed states are the stored energies in all the energy storage elements of the dc microgrid and power flowing into them. It is anticipated that calculating a large enough set of dissimilar transient scenarios will also span many scenarios not specifically used to develop the surface. These geometric manifolds will then be used as reference surfaces in any type of controller, such as a sliding mode hysteretic controller. The presence of switched power converters in microgrids involve different control actions for different system events. The control of the switch states of the converters is essential for steady state and transient operations. A digital memory look-up based controller that uses a hysteretic sliding mode control strategy is an effective technique to generate the proper switch states for the converters. An example dcmicrogrid with three dc-dc boost converters and resistive loads is considered for this work. The geometric manifolds are successfully generated for transient events, such as step changes in the loads and the sources. The surfaces corresponding to a specific case of step change in the loads are then used as reference surfaces in an EEPROM for experimentally validating the control strategy. The required switch states corresponding to this specific transient scenario are programmed in the EEPROM as a memory table. This controls the switching of the dc-dc boost converters and drives the system states to the reference manifold. In this work, it is shown that this strategy effectively controls the system for a transient condition such as step changes
20. Method of processing results of tests of heating surfaces of a steam generator on a digital computer
Energy Technology Data Exchange (ETDEWEB)
Glusker, B.N.
1975-03-01
At present, processing of information obtained by testing steam generators in high-capacity generating units is carried out manually. This takes a long time and does not always permit one to process all the information obtained, which impoverishes the results of experimental work. In addition, this kind of processing of experimental results is as a rule done after completion of a considerable part of the tests, and occasionally after completion of all the tests. In this case, it is impossible to conduct a better directed, corrected experiment, and this leads to duplication of experiments and to increasing the period of adjusting and exploratory work on industrial plants. An algorithm was developed for automated processing of the hydraulic and temperature conditions of the heating surfaces in steam generators on digital computers, which is a part of the general algorithm of processing of results of thermal tests of steam generators. It includes calculation of all characteristics determining the thermal and hydraulic conditions of the heating surfaces. The program of processing includes a subprogram: determination of the thermophysical and thermodynamic properties of the water and steam.
1. Surface defect detection in tiling Industries using digital image processing methods: analysis and evaluation.
Science.gov (United States)
2014-05-01
2. Where’s the Ground Surface? – Elevation Bias in LIDAR-derived Digital Elevation Models Due to Dense Vegetation in Oregon Tidal Marshes
Science.gov (United States)
Light Detection and Ranging (LIDAR) is a powerful resource for coastal and wetland managers and its use is increasing. Vegetation density and other land cover characteristics influence the accuracy of LIDAR-derived ground surface digital elevation models; however the degree to wh...
3. Job Assignments under Moral Hazard
DEFF Research Database (Denmark)
Koch, Alexander; Nafziger, Julia
Inefficient job assignments are usually explained with incomplete information about employees' abilities or contractual imperfections. We show that inefficient assignments arise even without uncertainty about the employee's ability and with complete contracts. Building on this result we provide...
4. PROCESSING OF DIGITAL IMAGES OF INDUSTRIAL OBJECT SURFACES DURING NON-DESTRUCTIVE TESTING
Directory of Open Access Journals (Sweden)
A. A. Hundzin
2016-01-01
Full Text Available The paper presents modern approaches to processing of images obtained with the help of industrial equipment. Usage of pixel modification in small neighborhoods, application of uniform image processing while changing brightness level, possibilities for combination of several images, threshold image processing have been described in the paper. While processing a number of images on a metal structure containing micro-cracks and being under strain difference between two such images have been determined in the paper. The metal structure represents a contour specifying the difference in images. An analysis of the contour makes it possible to determine initial direction of crack propagation in the metal. A threshold binarization value has been determined while processing the image having a field of medium intensity which are disappearing in the process of simple binarization and merging with the background due to rather small drop between the edges. In this regard an algorithm of a balanced threshold histogram clipping has been selected and it is based on the following approach: two different histogram fractions are “weighed” and if one of the fractions “outweighs” then last column of the histogram fraction is removed and the procedure is repeated again. When there is rather high threshold value a contour break (disappearance of informative pixels may occur, and when there is a low threshold value – a noise (non-informative pixels may appear. The paper shows implementation of an algorithm for location of contact pads on image of semiconductor crystal. Algorithms for morphological processing of production prototype images have been obtained in the paper and these algorithms permit to detect defects on the surface of semiconductors, to carry out filtration, threshold binarization that presupposes application of an algorithm of a balanced threshold histogram clipping. The developed approaches can be used to highlight contours on the surface
5. Accuracy Assessment of Digital Surface Models Based on WorldView-2 and ADS80 Stereo Remote Sensing Data
Directory of Open Access Journals (Sweden)
Christian Ginzler
2012-05-01
Full Text Available Digital surface models (DSMs are widely used in forest science to model the forest canopy. Stereo pairs of very high resolution satellite and digital aerial images are relatively new and their absolute accuracy for DSM generation is largely unknown. For an assessment of these input data two DSMs based on a WorldView-2 stereo pair and a ADS80 DSM were generated with photogrammetric instruments. Rational polynomial coefficients (RPCs are defining the orientation of the WorldView-2 satellite images, which can be enhanced with ground control points (GCPs. Thus two WorldView-2 DSMs were distinguished: a WorldView-2 RPCs-only DSM and a WorldView-2 GCP-enhanced RPCs DSM. The accuracy of the three DSMs was estimated with GPS measurements, manual stereo-measurements, and airborne laser scanning data (ALS. With GCP-enhanced RPCs the WorldView-2 image orientation could be optimised to a root mean square error (RMSE of 0.56 m in planimetry and 0.32 m in height. This improvement in orientation allowed for a vertical median error of −0.24 m for the WorldView-2 GCP-enhanced RPCs DSM in flat terrain. Overall, the DSM based on ADS80 images showed the highest accuracy of the three models with a median error of 0.08 m over bare ground. As the accuracy of a DSM varies with land cover three classes were distinguished: herb and grass, forests, and artificial areas. The study suggested the ADS80 DSM to best model actual surface height in all three land cover classes, with median errors < 1.1 m. The WorldView-2 GCP-enhanced RPCs model achieved good accuracy, too, with median errors of −0.43 m for the herb and grass vegetation and −0.26 m for artificial areas. Forested areas emerged as the most difficult land cover type for height modelling; still, with median errors of −1.85 m for the WorldView-2 GCP-enhanced RPCs model and −1.12 m for the ADS80 model, the input data sets evaluated here are quite promising for forest canopy modelling.
6. Specular and diffuse object extraction from a LiDAR derived Digital Surface Model (DSM)
International Nuclear Information System (INIS)
Saraf, N M; Hamid, J R A; Kamaruddin, M H
2014-01-01
This paper intents to investigate the indifferent behaviour quantitatively of target objects of interest due to specular and diffuse reflectivity based on generated LiDAR DSM of the study site in Ampang, Kuala Lumpur. The LiDAR data to be used was initially checked for its reliability and accuracy. The point cloud LiDAR data was converted to raster to allow grid analysis of the next process of generating the DSM and DTM. Filtering and masking were made removing the features of interest (i.e. building and tree) and other unwanted above surface features. A normalised DSM and object segmentation approach were conducted on the trees and buildings separately. Error assessment and findings attained were highlighted and documented. The result of LiDAR verification certified that the data is reliable and useable. The RMSE obtained is within the tolerance value of horizontal and vertical accuracy (x, y, z) i.e. 0.159 m, 0.211 m 0.091 m respectively. Building extraction inclusive of roof top based on slope and contour analysis undertaken indicate the capability of the approach while single tree extraction through aspect analysis appears to preserve the accuracy of the extraction accordingly. The paper has evaluated the suitable methods of extracting non-ground features and the effective segmentation of the LiDAR data
7. Sensitivity-Based Modeling of Evaluating Surface Runoff and Sediment Load using Digital and Analog Mechanisms
Directory of Open Access Journals (Sweden)
Olotu Yahaya
2014-07-01
Full Text Available Analyses of runoff- sediment measurement and evaluation using automated and convectional runoff-meters was carried out at Meteorological and Hydrological Station of Auchi Polytechnic, Auchi using two runoff plots (ABCDa and EFGHm of area 2m 2 each, depth 0.26 m and driven into the soil to the depth of 0.13m. Runoff depths and intensities were measured from each of the positioned runoff plot. Automated runoff-meter has a measuring accuracy of ±0.001l/±0.025 mm and rainfall depth-intensity was measured using tipping-bucket rainguage during the period of 14-month of experimentation. Minimum and maximum rainfall depths of 1.2 and 190.3 mm correspond to measured runoff depths (MRo of 0.0 mm for both measurement approaches and 60.4 mm and 48.9 mm respectively. Automated runoffmeter provides precise, accurate and instantaneous result over the convectional measurement of surface runoff. Runoff measuring accuracy for automated runoff-meter from the plot (ABCDa produces R 2 = 0.99; while R 2 = 0.96 for manual evaluation in plot (EFGHm. WEPP and SWAT models were used to simulate the obtained hydrological variables from the applied measurement mechanisms. The outputs of sensitivity simulation analysis indicate that data from automated measuring systems gives a better modelling index and such could be used for running robust runoff-sediment predictive modelling technique under different reservoir sedimentation and water management scenarios.
8. Digital fabrication
CERN Document Server
2012-01-01
The Winter 2012 (vol. 14 no. 3) issue of the Nexus Network Journal features seven original papers dedicated to the theme “Digital Fabrication”. Digital fabrication is changing architecture in fundamental ways in every phase, from concept to artifact. Projects growing out of research in digital fabrication are dependent on software that is entirely surface-oriented in its underlying mathematics. Decisions made during design, prototyping, fabrication and assembly rely on codes, scripts, parameters, operating systems and software, creating the need for teams with multidisciplinary expertise and different skills, from IT to architecture, design, material engineering, and mathematics, among others The papers grew out of a Lisbon symposium hosted by the ISCTE-Instituto Universitario de Lisboa entitled “Digital Fabrication – A State of the Art”. The issue is completed with four other research papers which address different mathematical instruments applied to architecture, including geometric tracing system...
9. Generation of Digital Surface Models from satellite photogrammetry: the DSM-OPT service of the ESA Geohazards Exploitation Platform (GEP)
Science.gov (United States)
Stumpf, André; Michéa, David; Malet, Jean-Philippe
2017-04-01
The continuously increasing fleet of agile stereo-capable very-high resolution (VHR) optical satellites has facilitated the acquisition of multi-view images of the earth surface. Theoretical revisit times have been reduced to less than one day and the highest spatial resolution which is commercially available amounts now to 30 cm/pixel. Digital Surface Models (DSM) and point clouds computed from such satellite stereo-acquisitions can provide valuable input for studies in geomorphology, tectonics, glaciology, hydrology and urban remote sensing The photogrammetric processing, however, still requires significant expertise, computational resources and costly commercial software. To enable a large Earth Science community (researcher and end-users) to process easily and rapidly VHR multi-view images, the work targets the implementation of a fully automatic satellite-photogrammetry pipeline (i.e DSM-OPT) on the ESA Geohazards Exploitation Platform (GEP). The implemented pipeline is based on the open-source photogrammetry library MicMac [1] and is designed for distributed processing on a cloud-based infrastructure. The service can be employed in pre-defined processing modes (i.e. urban, plain, hilly, and mountainous environments) or in an advanced processing mode (i.e. in which expert-users have the possibility to adapt the processing parameters to their specific applications). Four representative use cases are presented to illustrate the accuracy of the resulting surface models and ortho-images as well as the overall processing time. These use cases consisted of the construction of surface models from series of Pléiades images for four applications: urban analysis (Strasbourg, France), landslide detection in mountainous environments (South French Alps), co-seismic deformation in mountain environments (Central Italy earthquake sequence of 2016) and fault recognition for paleo-tectonic analysis (North-East India). Comparisons of the satellite-derived topography to airborne
10. COMPARATIVE ACCURACY EVALUATION OF FINE-SCALE GLOBAL AND LOCAL DIGITAL SURFACE MODELS: THE TSHWANE CASE STUDY I
Directory of Open Access Journals (Sweden)
A. Breytenbach
2016-10-01
Full Text Available Conducted in the City of Tshwane, South Africa, this study set about to test the accuracy of DSMs derived from different remotely sensed data locally. VHR digital mapping camera stereo-pairs, tri-stereo imagery collected by a Pléiades satellite and data detected from the Tandem-X InSAR satellite configuration were fundamental in the construction of seamless DSM products at different postings, namely 2 m, 4 m and 12 m. The three DSMs were sampled against independent control points originating from validated airborne LiDAR data. The reference surfaces were derived from the same dense point cloud at grid resolutions corresponding to those of the samples. The absolute and relative positional accuracies were computed using well-known DEM error metrics and accuracy statistics. Overall vertical accuracies were also assessed and compared across seven slope classes and nine primary land cover classes. Although all three DSMs displayed significantly more vertical errors where solid waterbodies, dense natural and/or alien woody vegetation and, in a lesser degree, urban residential areas with significant canopy cover were encountered, all three surpassed their expected positional accuracies overall.
11. Influence of track surface on the equine superficial digital flexor tendon loading in two horses at high speed trot.
Science.gov (United States)
Crevier-Denoix, N; Pourcelot, P; Ravary, B; Robin, D; Falala, S; Uzel, S; Grison, A C; Valette, J P; Denoix, J M; Chateau, H
2009-03-01
12. Quantification of morphological properties of terrace surface using digital elevation model and its application to stratigraphic correlation of terraces
International Nuclear Information System (INIS)
Yamamoto, Shinya; Hataya, Ryuta; Hamada, Takaomi
2008-01-01
Uplift estimation during late Quaternary is required for site selection of geological disposal facility of high level radioactive waste (NUMO, 2004). Terrace level and/or difference in elevation of terraces are good indicators of uplift. Therefore, a reliable method of terrace correlation and chronology is a key issues. Air-photograph interpretation is generally carried out in the early stage of a terrace investigation. However, a terrace classification often depends on the observer's qualitative interpretation. In order to improve objectivity of geomorphic investigation with air-photograph interpretation, we examine to quantify the morphological properties of terrace surface by some morphometric variables that are computed from Digital Elevation Model (DEM). In this study, four morphometric variables (average slope, average laplacian, remaining ratio of a terrace surface, and average depth of erosion) were calculated using data sets of terraces of which chronological data are clearly described. The relationship between these variables and terrace ages shows constant tendencies respond to the geomorphological process caused by the erosion. To examine capability of morphometric variables as an index of terrace correlation, regression analyses were carried out. The regression age estimated from morphometric variables allows to classify terraces in correct sequence, and the error with the observed age falls up to 100,000 years. In addition, to discuss appropriate quantities of DEM for terrace correlation, we used three different elevation data to create DEM: 1) aerial photogrammetry data; 2) airborne laser scanner data; 3) 1:25000-scale contour map. By comparing analysis results of each DEMs, we show suitable qualities of elevation data and DEM grid size to represent the degree of erosion correctly. (author)
International Nuclear Information System (INIS)
Park, Ji Hyeong
1999-06-01
14. Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system in Florida and parts of Georgia, Alabama, and South Carolina
Science.gov (United States)
Williams, Lester J.; Dixon, Joann F.
2015-01-01
Digital surfaces and thicknesses of selected hydrogeologic units of the Floridan aquifer system were developed to define an updated hydrogeologic framework as part of the U.S. Geological Survey Groundwater Resources Program. The dataset contains structural surfaces depicting the top and base of the aquifer system, its major and minor hydrogeologic units and zones, geophysical marker horizons, and the altitude of the 10,000-milligram-per-liter total dissolved solids boundary that defines the approximate fresh and saline parts of the aquifer system. The thicknesses of selected major and minor units or zones were determined by interpolating points of known thickness or from raster surface subtraction of the structural surfaces. Additional data contained include clipping polygons; regional polygon features that represent geologic or hydrogeologic aspects of the aquifers and the minor units or zones; data points used in the interpolation; and polygon and line features that represent faults, boundaries, and other features in the aquifer system.
15. Game theory and traffic assignment.
Science.gov (United States)
2013-09-01
Traffic assignment is used to determine the number of users on roadway links in a network. While this problem has : been widely studied in transportation literature, its use of the concept of equilibrium has attracted considerable interest : in the f...
16. UOP LDR 300 All Assignments New
OpenAIRE
2018-01-01
UOP LDR 300 All Assignments New Check this A+ tutorial guideline at http://www.ldr300assignment.com/ldr-300-uop/ldr-300-all-assignments-latest For more classes visit http://www.ldr300assignment.com LDR 300 Week 1 Assignment Leadership Assessment (2 Papers) LDR 300 Week 2 Assignment Leadership Theories Matrix (2 Set) LDR 300 Week 2 Assignment Formulating Leadership Part I (2 Papers) LDR 300 Week 3 Assignment Interaction and Influence Amo...
17. Comparative accuracy evaluation of fine-scale global and local digital surface models: The Tshwane Case Study I
CSIR Research Space (South Africa)
Breytenbach, Andre
2016-10-01
Full Text Available Conducted in the City of Tshwane, South Africa, this study set about to test the accuracy of DSMs derived from different remotely sensed data locally. VHR digital mapping camera stereo-pairs, tri-stereo imagery collected by a Pléiades satellite...
18. Comparison of Surface Flow Features from Lidar-Derived Digital Elevation Models with Historical Elevation and Hydrography Data for Minnehaha County, South Dakota
Science.gov (United States)
Poppenga, Sandra K.; Worstell, Bruce B.; Stoker, Jason M.; Greenlee, Susan K.
2009-01-01
The U.S. Geological Survey (USGS) has taken the lead in the creation of a valuable remote sensing product by incorporating digital elevation models (DEMs) derived from Light Detection and Ranging (lidar) into the National Elevation Dataset (NED), the elevation layer of 'The National Map'. High-resolution lidar-derived DEMs provide the accuracy needed to systematically quantify and fully integrate surface flow including flow direction, flow accumulation, sinks, slope, and a dense drainage network. In 2008, 1-meter resolution lidar data were acquired in Minnehaha County, South Dakota. The acquisition was a collaborative effort between Minnehaha County, the city of Sioux Falls, and the USGS Earth Resources Observation and Science (EROS) Center. With the newly acquired lidar data, USGS scientists generated high-resolution DEMs and surface flow features. This report compares lidar-derived surface flow features in Minnehaha County to 30- and 10-meter elevation data previously incorporated in the NED and ancillary hydrography datasets. Surface flow features generated from lidar-derived DEMs are consistently integrated with elevation and are important in understanding surface-water movement to better detect surface-water runoff, flood inundation, and erosion. Many topographic and hydrologic applications will benefit from the increased availability of accurate, high-quality, and high-resolution surface-water data. The remotely sensed data provide topographic information and data integration capabilities needed for meeting current and future human and environmental needs.
19. Effective Homework Assignments. Research Brief
Science.gov (United States)
Cooper, Harris
2008-01-01
Perhaps more than any question other than "How much time should students spend doing homework?" parents and educators want to know, "What kinds of homework assignments are most effective?" Clearly, the answers to this question vary according to many factors, especially the developmental level of students and the topic area. Generally, answers are…
20. Assigning agents to a line
DEFF Research Database (Denmark)
Hougaard, Jens Leth; Moreno-Ternero, Juan D.; Østerdal, Lars Peter Raahave
2014-01-01
minimizing modification of the classic random priority method to solve this class of problems. We also provide some logical relations in our setting among standard axioms in the literature on assignment problems, and explore the robustness of our results to several extensions of our setting....
1. A "Journey in Feminist Theory Together": The "Doing Feminist Theory through Digital Video" Project
Science.gov (United States)
Hurst, Rachel Alpha Johnston
2014-01-01
"Doing Feminist Theory Through Digital Video" is an assignment I designed for my undergraduate feminist theory course, where students created a short digital video on a concept in feminist theory. I outline the assignment and the pedagogical and epistemological frameworks that structured the assignment (digital storytelling,…
2. Digital holographic profilometry of the inner surface of a pipe using a current-induced wavelength change of a laser diode.
Science.gov (United States)
2011-07-20
Phase-shifting digital holography is applied to the measurement of the surface profile of the inner surface of a pipe for the detection of a hole in its wall. For surface contouring of the inner wall, a two-wavelength method involving an injection-current-induced wavelength change of a laser diode is used. To illuminate and obtain information on the inner surface, a cone-shaped mirror is set inside the pipe and moved along in a longitudinal direction. The distribution of a calculated optical path length in an experimental alignment is used to compensate for the distortion due to the misalignment of the mirror in the pipe. Using the proposed method, two pieces of metal sheet pasted on the inner wall of the pipe and a hole in the wall are detected. This shows that the three-dimensional profile of a metal plate on the inner wall of a pipe can be measured using simple image processing. © 2011 Optical Society of America
3. Three-dimensional quantification of cardiac surface motion: a newly developed three-dimensional digital motion-capture and reconstruction system for beating heart surgery.
Science.gov (United States)
Watanabe, Toshiki; Omata, Sadao; Odamura, Motoki; Okada, Masahumi; Nakamura, Yoshihiko; Yokoyama, Hitoshi
2006-11-01
This study aimed to evaluate our newly developed 3-dimensional digital motion-capture and reconstruction system in an animal experiment setting and to characterize quantitatively the three regional cardiac surface motions, in the left anterior descending artery, right coronary artery, and left circumflex artery, before and after stabilization using a stabilizer. Six pigs underwent a full sternotomy. Three tiny metallic markers (diameter 2 mm) coated with a reflective material were attached on three regional cardiac surfaces (left anterior descending, right coronary, and left circumflex coronary artery regions). These markers were captured by two high-speed digital video cameras (955 frames per second) as 2-dimensional coordinates and reconstructed to 3-dimensional data points (about 480 xyz-position data per second) by a newly developed computer program. The remaining motion after stabilization ranged from 0.4 to 1.01 mm at the left anterior descending, 0.91 to 1.52 mm at the right coronary artery, and 0.53 to 1.14 mm at the left circumflex regions. Significant differences before and after stabilization were evaluated in maximum moving velocity (left anterior descending 456.7 +/- 178.7 vs 306.5 +/- 207.4 mm/s; right coronary artery 574.9 +/- 161.7 vs 446.9 +/- 170.7 mm/s; left circumflex 578.7 +/- 226.7 vs 398.9 +/- 192.6 mm/s; P heart surface movement. This helps us better understand the complexity of the heart, its motion, and the need for developing a better stabilizer for beating heart surgery.
4. Generating 3D and 3D-like animations of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs.
Science.gov (United States)
Hortolà, Policarp
2010-01-01
When dealing with microscopic still images of some kinds of samples, the out-of-focus problem represents a particularly serious limiting factor for the subsequent generation of fully sharp 3D animations. In order to produce fully-focused 3D animations of strongly uneven surface microareas, a vertical stack of six digital secondary-electron SEM micrographs of a human bloodstain microarea was acquired. Afterwards, single combined images were generated using a macrophotography and light microscope image post-processing software. Subsequently, 3D animations of texture and topography were obtained in different formats using a combination of software tools. Finally, a 3D-like animation of a texture-topography composite was obtained in different formats using another combination of software tools. By one hand, results indicate that the use of image post-processing software not concerned primarily with electron micrographs allows to obtain, in an easy way, fully-focused images of strongly uneven surface microareas of bloodstains from small series of partially out-of-focus digital SEM micrographs. On the other hand, results also indicate that such small series of electron micrographs can be utilized for generating 3D and 3D-like animations that can subsequently be converted into different formats, by using certain user-friendly software facilities not originally designed for use in SEM, that are easily available from Internet. Although the focus of this study was on bloodstains, the methods used in it well probably are also of relevance for studying the surface microstructures of other organic or inorganic materials whose sharp displaying is difficult of obtaining from a single SEM micrograph.
5. A Statistical Programme Assignment Model
DEFF Research Database (Denmark)
Rosholm, Michael; Staghøj, Jonas; Svarer, Michael
When treatment effects of active labour market programmes are heterogeneous in an observable way across the population, the allocation of the unemployed into different programmes becomes a particularly important issue. In this paper, we present a statistical model designed to improve the present...... duration of unemployment spells may result if a statistical programme assignment model is introduced. We discuss several issues regarding the plementation of such a system, especially the interplay between the statistical model and case workers....
6. Accuracy assessment of digital surface models based on a small format action camera in a North-East Hungarian sample area
Directory of Open Access Journals (Sweden)
Barkóczi Norbert
2017-01-01
Full Text Available The use of the small format digital action cameras has been increased in the past few years in various applications, due to their low budget cost, flexibility and reliability. We can mount these small cameras on several devices, like unmanned air vehicles (UAV and create 3D models with photogrammetric technique. Either creating or receiving these kind of databases, one of the most important questions will always be that how accurate these systems are, what the accuracy that can be achieved is. We gathered the overlapping images, created point clouds, and then we generated 21 different digital surface models (DSM. The differences based on the number of images we used in each model, and on the flight height. We repeated the flights three times, to compare the same models with each other. Besides, we measured 129 reference points with RTK-GPS, to compare the height differences with the extracted cell values from each DSM. The results showed that higher flight height has lower errors, and the optimal air base distance is one fourth of the flying height in both cases. The lowest median was 0.08 meter, at the 180 meter flight, 50 meter air base distance model. Raising the number of images does not increase the overall accuracy. The connection between the amount of error and distance from the nearest GCP is not linear in every case.
7. A note on ranking assignments using reoptimization
DEFF Research Database (Denmark)
Pedersen, Christian Roed; Nielsen, L.R.; Andersen, K.A.
2005-01-01
We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...
8. An algorithm for ranking assignments using reoptimization
DEFF Research Database (Denmark)
Pedersen, Christian Roed; Nielsen, Lars Relund; Andersen, Kim Allan
2008-01-01
We consider the problem of ranking assignments according to cost in the classical linear assignment problem. An algorithm partitioning the set of possible assignments, as suggested by Murty, is presented where, for each partition, the optimal assignment is calculated using a new reoptimization...... technique. Computational results for the new algorithm are presented...
9. Global digital data sets of soil type, soil texture, surface slope and other properties: Documentation of archived data tape
Science.gov (United States)
Staub, B.; Rosenzweig, C.; Rind, D.
1987-01-01
The file structure and coding of four soils data sets derived from the Zobler (1986) world soil file is described. The data were digitized on a one-degree square grid. They are suitable for large-area studies such as climate research with general circulation models, as well as in forestry, agriculture, soils, and hydrology. The first file is a data set of codes for soil unit, land-ice, or water, for all the one-degree square cells on Earth. The second file is a data set of codes for texture, land-ice, or water, for the same soil units. The third file is a data set of codes for slope, land-ice, or water for the same units. The fourth file is the SOILWRLD data set, containing information on soil properties of land cells of both Matthews' and Food and Agriculture Organization (FAO) sources. The fourth file reconciles land-classification differences between the two and has missing data filled in.
10. Using HL7 in hospital staff assignments.
Science.gov (United States)
Unluturk, Mehmet S
2014-02-01
11. Integrated assignment and path planning
Science.gov (United States)
Murphey, Robert A.
2005-11-01
A surge of interest in unmanned systems has exposed many new and challenging research problems across many fields of engineering and mathematics. These systems have the potential of transforming our society by replacing dangerous and dirty jobs with networks of moving machines. This vision is fundamentally separate from the modern view of robotics in that sophisticated behavior is realizable not by increasing individual vehicle complexity, but instead through collaborative teaming that relies on collective perception, abstraction, decision making, and manipulation. Obvious examples where collective robotics will make an impact include planetary exploration, space structure assembly, remote and undersea mining, hazardous material handling and clean-up, and search and rescue. Nonetheless, the phenomenon driving this technology trend is the increasing reliance of the US military on unmanned vehicles, specifically, aircraft. Only a few years ago, following years of resistance to the use of unmanned systems, the military and civilian leadership in the United States reversed itself and have recently demonstrated surprisingly broad acceptance of increasingly pervasive use of unmanned platforms in defense surveillance, and even attack. However, as rapidly as unmanned systems have gained acceptance, the defense research community has discovered the technical pitfalls that lie ahead, especially for operating collective groups of unmanned platforms. A great deal of talent and energy has been devoted to solving these technical problems, which tend to fall into two categories: resource allocation of vehicles to objectives, and path planning of vehicle trajectories. An extensive amount of research has been conducted in each direction, yet, surprisingly, very little work has considered the integrated problem of assignment and path planning. This dissertation presents a framework for studying integrated assignment and path planning and then moves on to suggest an exact
12. Managing voluntary turnover through challenging assignments
NARCIS (Netherlands)
Preenen, P.T.Y.; de Pater, I.E.; van Vianen, A.E.M.; Keijzer, L.
2011-01-01
This study examines employees’ challenging assignments as manageable means to reduce turnover intentions, job search behaviors, and voluntary turnover. Results indicate that challenging assignments are negatively related to turnover intentions and job search behaviors and that these relationships
13. Managing voluntary turnover through challenging assignments
NARCIS (Netherlands)
Preenen, P.T.Y.; Pater, I.E. de; Vianen, A.E.M. van; Keijzer, L.
2011-01-01
This study examines employees' challenging assignments as manageable means to reduce turnover intentions, job search behaviors, and voluntary turnover. Results indicate that challenging assignments are negatively related to turnover intentions and job search behaviors and that these relationships
14. A feedback model of figure-ground assignment.
Science.gov (United States)
Domijan, Drazen; Setić, Mia
2008-05-30
A computational model is proposed in order to explain how bottom-up and top-down signals are combined into a unified perception of figure and background. The model is based on the interaction between the ventral and the dorsal stream. The dorsal stream computes saliency based on boundary signals provided by the simple and the complex cortical cells. Output from the dorsal stream is projected to the surface network which serves as a blackboard on which the surface representation is formed. The surface network is a recurrent network which segregates different surfaces by assigning different firing rates to them. The figure is labeled by the maximal firing rate. Computer simulations showed that the model correctly assigns figural status to the surface with a smaller size, a greater contrast, convexity, surroundedness, horizontal-vertical orientation and a higher spatial frequency content. The simple gradient of activity in the dorsal stream enables the simulation of the new principles of the lower region and the top-bottom polarity. The model also explains how the exogenous attention and the endogenous attention may reverse the figural assignment. Due to the local excitation in the surface network, neural activity at the cued region will spread over the whole surface representation. Therefore, the model implements the object-based attentional selection.
Science.gov (United States)
Nickenig, Hans-Joachim; Wichmann, Manfred; Schlegel, Karl Andreas; Nkenke, Emeka; Eitner, Stephan
2009-06-01
16. Heteronuclear 2D NMR studies on an engineered insulin monomer: Assignments and characterization of the receptor-binding surface by selective 2H and 13C labeling with application to protein design
International Nuclear Information System (INIS)
Weiss, M.A.; Hua, Qingxin; Lynch, C.S.; Shoelson, S.E.; Frank, B.H.
1991-01-01
Insulin provides an important model for the application of genetic engineering to rational protein design and has been well characterized in the crystal state. However, self-association of insulin in solution has precluded complementary 2D NMR study under physiological conditions. The authors demonstrate here that such limitations may be circumvented by the use of a monomeric analogue that contains three amino acid substitutions on the protein surface (HisB10 → Asp, ProB28 → Lys, and LysB29 → Pro); this analogue (designated DKP-insulin) retains native receptor-binding potency. Comparative 1 H NMR studies of native human insulin and a series of three related analogues-(i) the singly substituted analogue [HisB10→Asp], (ii) the doubly substituted analogue [ProB28→Lys; LysB29→Pro], and (iii) DKP-insulin-demonstrate progressive reduction in concentration-dependent line-broadening in accord with the results of analytical ultracentrifugation. Extensive nonlocal interactions are observed in the NOESY spectrum of DKP-insulin, indicating that this analogue adopts a compact and stably folded structure as a monomer in overall accord with crystal models. Site-specific 2 H and 13 C isotopic labels are introduced by semisynthesis as probes for the structure and dynamics of the receptor-binding surface. These studies confirm and extend under physiological conditions the results of a previous 2D NMR analysis of native insulin in 20% acetic acid. Implications for the role of protein flexibility in receptor recognition are discussed with application to the design of novel insulin analogues
17. 24 CFR 221.255 - Assignment option.
Science.gov (United States)
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.255 Section... Assignment option. (a) A mortgagee holding a mortgage insured pursuant to a conditional or firm commitment issued on or before November 30, 1983 has the option to assign, transfer and deliver to the Commissioner...
18. 24 CFR 221.770 - Assignment option.
Science.gov (United States)
2010-04-01
... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Assignment option. 221.770 Section... § 221.770 Assignment option. A mortgagee holding a conditional or firm commitment issued on or before... mortgagee's approved underwriter on or before November 30, 1983) has the option to assign, transfer and...
19. Solving the rectangular assignment problem and applications
NARCIS (Netherlands)
Bijsterbosch, J.; Volgenant, A.
2010-01-01
The rectangular assignment problem is a generalization of the linear assignment problem (LAP): one wants to assign a number of persons to a smaller number of jobs, minimizing the total corresponding costs. Applications are, e.g., in the fields of object recognition and scheduling. Further, we show
International Nuclear Information System (INIS)
Brody, W.R.
1984-01-01
Digital Radiography begins with an orderly introduction to the fundamental concepts of digital imaging. The entire X-ray digital imagining system is described, from an overall characterization of image quality to specific components required for a digital radiographic system. Because subtraction is central to digital radiographic systems, the author details the use of various subtraction methods for image enhancement. Complex concepts are illustrated with numerous examples and presented in terms that can readily be understood by physicians without an advanced mathematics background. The second part of the book discusses implementations and applications of digital imagining systems based on area and scanned detector technologies. This section includes thorough coverage of digital fluoroscopy, scanned projection radiography, and film-based digital imaging systems, and features a state-of-the-art synopsis of the applications of digital subtraction angiography. The book concludes with a timely assessment of anticipated technological advances
1. Symmetric reconfigurable capacity assignment in a bidirectional DWDM access network.
Science.gov (United States)
Ortega, Beatriz; Mora, José; Puerto, Gustavo; Capmany, José
2007-12-10
This paper presents a novel architecture for DWDM bidirectional access networks providing symmetric dynamic capacity allocation for both downlink and uplink signals. A foldback arrayed waveguide grating incorporating an optical switch enables the experimental demonstration of flexible assignment of multiservice capacity. Different analog and digital services, such as CATV, 10 GHz-tone, 155Mb/s PRBS and UMTS signals have been transmitted in order to successfully test the system performance under different scenarios of total capacity distribution from the Central Station to different Base Stations with two reconfigurable extra channels for each down and upstream direction.
2. Digital Culture and Digital Library
Directory of Open Access Journals (Sweden)
Yalçın Yalçınkaya
2016-12-01
Full Text Available In this study; digital culture and digital library which have a vital connection with each other are examined together. The content of the research consists of the interaction of culture, information, digital culture, intellectual technologies, and digital library concepts. The study is an entry work to integrity of digital culture and digital library theories and aims to expand the symmetry. The purpose of the study is to emphasize the relation between the digital culture and digital library theories acting intersection of the subjects that are examined. Also the perspective of the study is based on examining the literature and analytical evaluation in both studies (digital culture and digital library. Within this context, the methodology of the study is essentially descriptive and has an attribute for the transmission and synthesis of distributed findings produced in the field of the research. According to the findings of the study results, digital culture is an inclusive term that describes the effects of intellectual technologies in the field of information and communication. Information becomes energy and the spectrum of the information is expanding in the vertical rise through the digital culture. In this context, the digital library appears as a new living space of a new environment. In essence, the digital library is information-oriented; has intellectual technology support and digital platform; is in a digital format; combines information resources and tools in relationship/communication/cooperation by connectedness, and also it is the dynamic face of the digital culture in time and space independence. Resolved with the study is that the digital libraries are active and effective in the formation of global knowing and/or mass wisdom in the process of digital culture.
3. SENTINEL-2 GLOBAL REFERENCE IMAGE VALIDATION AND APPLICATION TO MULTITEMPORAL PERFORMANCES AND HIGH LATITUDE DIGITAL SURFACE MODEL
Directory of Open Access Journals (Sweden)
A. Gaudel
2017-05-01
Full Text Available In the frame of the Copernicus program of the European Commission, Sentinel-2 is a constellation of 2 satellites with a revisit time of 5 days in order to have temporal images stacks and a global coverage over terrestrial surfaces. Satellite 2A was launched in June 2015, and satellite 2B will be launched in March 2017. In cooperation with the European Space Agency (ESA, the French space agency (CNES is in charge of the image quality of the project, and so ensures the CAL/VAL commissioning phase during the months following the launch. This cooperation is also extended to routine phase as CNES supports European Space Research Institute (ESRIN and the Sentinel-2 Mission performance Centre (MPC for validation in geometric and radiometric image quality aspects, and in Sentinel-2 GRI geolocation performance assessment whose results will be presented in this paper. The GRI is a set of S2A images at 10m resolution covering the whole world with a good and consistent geolocation. This ground reference enables accurate multi-temporal registration of refined Sentinel-2 products. While not primarily intended for the generation of DSM, Sentinel-2 swaths overlap between orbits would also allow for the generation of a complete DSM of land and ices over 60° of northern latitudes (expected accuracy: few S2 pixels in altimetry. This DSM would benefit from the very frequent revisit times of Sentinel-2, to monitor ice or snow level in area of frequent changes, or to increase measurement accuracy in areas of little changes.
4. SENTINEL-2 Global Reference Image Validation and Application to Multitemporal Performances and High Latitude Digital Surface Model
Science.gov (United States)
Gaudel, A.; Languille, F.; Delvit, J. M.; Michel, J.; Cournet, M.; Poulain, V.; Youssefi, D.
2017-05-01
In the frame of the Copernicus program of the European Commission, Sentinel-2 is a constellation of 2 satellites with a revisit time of 5 days in order to have temporal images stacks and a global coverage over terrestrial surfaces. Satellite 2A was launched in June 2015, and satellite 2B will be launched in March 2017. In cooperation with the European Space Agency (ESA), the French space agency (CNES) is in charge of the image quality of the project, and so ensures the CAL/VAL commissioning phase during the months following the launch. This cooperation is also extended to routine phase as CNES supports European Space Research Institute (ESRIN) and the Sentinel-2 Mission performance Centre (MPC) for validation in geometric and radiometric image quality aspects, and in Sentinel-2 GRI geolocation performance assessment whose results will be presented in this paper. The GRI is a set of S2A images at 10m resolution covering the whole world with a good and consistent geolocation. This ground reference enables accurate multi-temporal registration of refined Sentinel-2 products. While not primarily intended for the generation of DSM, Sentinel-2 swaths overlap between orbits would also allow for the generation of a complete DSM of land and ices over 60° of northern latitudes (expected accuracy: few S2 pixels in altimetry). This DSM would benefit from the very frequent revisit times of Sentinel-2, to monitor ice or snow level in area of frequent changes, or to increase measurement accuracy in areas of little changes.
5. Digital mammography; Mamografia digital
Energy Technology Data Exchange (ETDEWEB)
Chevalier, M.; Torres, R.
2010-07-01
Mammography represents one of the most demanding radiographic applications, simultaneously requiring excellent contrast sensitivity, high spatial resolution, and wide dynamic range. Film/screen is the most widely extended image receptor in mammography due to both its high spatial resolution and contrast. The film/screen limitations are related with its narrow latitude, structural noise and that is at the same time the medium for the image acquisition, storage and presentation. Several digital detector made with different technologies can overcome these difficulties. Here, these technologies as well as their main advantages and disadvantages are analyzed. Also it is discussed its impact on the mammography examinations, mainly on the breast screening programs. (Author).
6. Integration of thermal digital 3D model and a MASW (Multichannel Analysis of Surface Wave) as a means of improving monitoring of spoil tip stability
Science.gov (United States)
Lewińska, Paulina; Matuła, Rafał; Dyczko, Artur
2018-01-01
Spoil tips are anthropogenic terrain structures built of leftover (coal) mining materials. They consist mostly of slate and sandstone or mudstone but also include coal and highly explosive coal dust. Coal soil tip fires cause an irreversible degradation to the environment. Government organizations notice the potential problem of spoil tip hazard and are looking for ways of fast monitoring of their temperature and inside structure. In order to test new monitoring methods an experimental was performed in the area of spoil tip of Lubelski Węgiel "Bogdanka" S.A. A survey consisted of creating a 3D discreet thermal model. This was done in order to look for potential fire areas. MASW (Multichannel analysis of surface wave) was done in order to find potential voids within the body of a tip. Existing data was digitalized and a 3D model of object's outside and inside was produced. This article provides results of this survey and informs about advantages of such an approach.
7. Estimation of mean tree stand volume using high-resolution aerial RGB imagery and digital surface model, obtained from sUAV and Trestima mobile application
Directory of Open Access Journals (Sweden)
G. K. Rybakov
2017-06-01
Full Text Available This study considers a remote sensing technique for mean volume estimation based on a very high-resolution (VHR aerial RGB imagery obtained using a small-sized unmanned aerial vehicle (sUAV and a high-resolution photogrammetric digital surface model (DSM as well as an innovative technology for field measurements (Trestima. The study area covers approx. 220 ha of forestland in Finland. The work concerns the entire process from remote sensing and field data acquisition to statistical analysis and forest volume wall-to-wall mapping. The study showed that the VHR aerial imagery and the high-resolution DSM produced based on the application of the sUAV have good prospects for forest inventory. For the sUAV based estimation of forest variables such as Height, Basal Area and mean Volume, Root Mean Square Error constituted 6.6 %, 22.6 % and 26.7 %, respectively. Application of Trestima for estimation of the mean volume of the standing forest showed minor difference over the existing Forest Management Plan at all the selected forest compartments. Simultaneously, the results of the study confirmed that the technologies and the tools applied at this work could be a reliable and potentially cost-effective means of forest data acquisition with high potential of operational use.
8. Integration of thermal digital 3D model and a MASW (Multichannel Analysis of Surface Wave as a means of improving monitoring of spoil tip stability
Directory of Open Access Journals (Sweden)
Lewińska Paulina
2018-01-01
Full Text Available Spoil tips are anthropogenic terrain structures built of leftover (coal mining materials. They consist mostly of slate and sandstone or mudstone but also include coal and highly explosive coal dust. Coal soil tip fires cause an irreversible degradation to the environment. Government organizations notice the potential problem of spoil tip hazard and are looking for ways of fast monitoring of their temperature and inside structure. In order to test new monitoring methods an experimental was performed in the area of spoil tip of Lubelski Węgiel „Bogdanka” S.A. A survey consisted of creating a 3D discreet thermal model. This was done in order to look for potential fire areas. MASW (Multichannel analysis of surface wave was done in order to find potential voids within the body of a tip. Existing data was digitalized and a 3D model of object’s outside and inside was produced. This article provides results of this survey and informs about advantages of such an approach.
9. Digital Tectonics
DEFF Research Database (Denmark)
Christiansen, Karl; Borup, Ruben; Søndergaard, Asbjørn
2014-01-01
Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated.......Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated....
10. Digital squares
DEFF Research Database (Denmark)
Forchhammer, Søren; Kim, Chul E
1988-01-01
Digital squares are defined and their geometric properties characterized. A linear time algorithm is presented that considers a convex digital region and determines whether or not it is a digital square. The algorithm also determines the range of the values of the parameter set of its preimages....... The analysis involves transforming the boundary of a digital region into parameter space of slope and y-intercept...
11. Digital skrivedidaktik
DEFF Research Database (Denmark)
Digital skrivedidaktik består af to dele. Første del præsenterer teori om skrivekompetence og digital skrivning. Digital skrivning er karakteriseret ved at tekster skrives på computer og med digitale værktøjer, hvilket ændrer skrivningens traditionelle praksis, produkt og processer. Hvad er digital...... om elevens skriveproces) og Blogskrivning (der styrker eleverne i at bruge blogs i undervisningen)....
12. Digital Citizenship
Science.gov (United States)
Isman, Aytekin; Canan Gungoren, Ozlem
2014-01-01
Era in which we live is known and referred as digital age.In this age technology is rapidly changed and developed. In light of these technological advances in 21st century, schools have the responsibility of training "digital citizen" as well as a good citizen. Digital citizens must have extensive skills, knowledge, Internet and …
13. Work Term Assignment Spring 2017
Science.gov (United States)
Sico, Mallory
2017-01-01
My tour in the Engineering Robotics directorate exceeded my expectations. I learned lessons about Creo, manufacturing and assembly, collaboration, and troubleshooting. During my first tour, last spring, I used Creo on a smaller project, but had limited experience with it before starting in the Dynamic Systems Test branch this spring. I gained valuable experience learning assembly design, sheet metal design and designing with intent for manufacturing and assembly. These skills came from working both on the hatch and the floor. I also learned to understand the intent of other designers on models I worked with. While redesigning the floor, I was modifying an existing part and worked to understand what the previous designer had done to make it fit with the new model. Through working with the machine shop and in the mock-up, I learned much more about manufacturing and assembly. I used a Dremel, rivet gun, belt sander, and countersink for the first time. Through taking multiple safety training for different machine shops, I learned new machine shop safety skills specific to each one. This semester also gave me new collaborative opportunities. I collaborated with engineers within my branch as well as with Human Factors and the building 10 machine shop. This experience helped me learn how to design for functionality and assembly, not only for what would be easiest in my designs. In addition to these experiences, I learned many lessons in troubleshooting. I was the first person in my office to use a Windows 10 computer. This caused unexpected issues with NASA services and programs, such as the Digital Data Management Server (DDMS). Because of this, I gained experience finding solutions to lockout and freeze issues as well as Creo specific settings. These will be useful skills to have in the future and will be implemented in future rotations. This co-op tour has motivated me more to finish my degree and pursue my academic goals. I intend to take a machining Career Gateway
14. Digital subtraktion
DEFF Research Database (Denmark)
Mussmann, Bo Redder
2004-01-01
Digital subtraktion er en metode til at fjerne uønskede oplysninger i et røntgenbillede. Subtraktionsteknikken bruges primært i forbindelse med angiografi hvor man kun er interesseret i at se selve karret. Derfor er digital subtraktion i daglig tale synonymt med DSA eller DVI – hhv. Digital...... Subtraction Angiography eller Digital Vascular Imaging. Benævnelserne er to røntgenfirmaers navn for den samme teknik. Digital subtraktion kræver speciel software, samt at apparaturet kan eksponere i serier....
15. Digital preservation
CERN Document Server
Deegan, Marilyn
2013-01-01
Digital preservation is an issue of huge importance to the library and information profession right now. With the widescale adoption of the internet and the rise of the world wide web, the world has been overwhelmed by digital information. Digital data is being produced on a massive scale by individuals and institutions: some of it is born, lives and dies only in digital form, and it is the potential death of this data, with its impact on the preservation of culture, that is the concern of this book. So how can information professionals try to remedy this? Digital preservation is a complex iss
16. Digital Natives or Digital Tribes?
Science.gov (United States)
Watson, Ian Robert
2013-01-01
This research builds upon the discourse surrounding digital natives. A literature review into the digital native phenomena was undertaken and found that researchers are beginning to identify the digital native as not one cohesive group but of individuals influenced by other factors. Primary research by means of questionnaire survey of technologies…
17. A tri-objective, dynamic weapon assignment model for surface ...
African Journals Online (AJOL)
2015-05-11
May 11, 2015 ... metaheuristic for solving the vehicle routing problem with time .... them the dynamic programming formulation by Bradford [3] in 1961, the nonlinear pro- ..... The concept of multi-objective optimisation naturally gives rise to the ...
18. Assessing the Accuracy of High Resolution Digital Surface Models Computed by PhotoScan® and MicMac® in Sub-Optimal Survey Conditions
Directory of Open Access Journals (Sweden)
Marion Jaud
2016-06-01
Full Text Available For monitoring purposes and in the context of geomorphological research, Unmanned Aerial Vehicles (UAV appear to be a promising solution to provide multi-temporal Digital Surface Models (DSMs and orthophotographs. There are a variety of photogrammetric software tools available for UAV-based data. The objective of this study is to investigate the level of accuracy that can be achieved using two of these software tools: Agisoft PhotoScan® Pro and an open-source alternative, IGN© MicMac®, in sub-optimal survey conditions (rugged terrain, with a large variety of morphological features covering a range of roughness sizes, poor GPS reception. A set of UAV images has been taken by a hexacopter drone above the Rivière des Remparts, a river on Reunion Island. This site was chosen for its challenging survey conditions: the topography of the study area (i involved constraints on the flight plan; (ii implied errors on some GPS measurements; (iii prevented an optimal distribution of the Ground Control Points (GCPs and; (iv was very complex to reconstruct. Several image processing tests are performed with different scenarios in order to analyze the sensitivity of each software package to different parameters (image quality, numbers of GCPs, etc.. When computing the horizontal and vertical errors within a control region on a set of ground reference targets, both methods provide rather similar results. A precision up to 3–4 cm is achievable with these software packages. The DSM quality is also assessed over the entire study area comparing PhotoScan DSM and MicMac DSM with a Terrestrial Laser Scanner (TLS point cloud. PhotoScan and MicMac DSM are also compared at the scale of particular features. Both software packages provide satisfying results: PhotoScan is more straightforward to use but its source code is not open; MicMac is recommended for experimented users as it is more flexible.
19. 32 CFR 884.2 - Assigned responsibilities.
Science.gov (United States)
2010-07-01
... OF PERSONNEL TO UNITED STATES CIVILIAN AUTHORITIES FOR TRIAL § 884.2 Assigned responsibilities. (a... 32 National Defense 6 2010-07-01 2010-07-01 false Assigned responsibilities. 884.2 Section 884.2... requests for return of members to the United States for delivery to civilian authorities when the request...
20. 12 CFR 563e.28 - Assigned ratings.
Science.gov (United States)
2010-01-01
... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Assigned ratings. 563e.28 Section 563e.28 Banks... for Assessing Performance § 563e.28 Assigned ratings. (a) Ratings in general. Subject to paragraphs (b... performance under the lending, investment and service tests, the community development test, the small savings...
1. Stress Assignment in Reading Italian Polysyllabic Pseudowords
Science.gov (United States)
Sulpizio, Simone; Arduino, Lisa S.; Paizi, Despina; Burani, Cristina
2013-01-01
In 4 naming experiments we investigated how Italian readers assign stress to pseudowords. We assessed whether participants assign stress following distributional information such as stress neighborhood (the proportion and number of existent words sharing orthographic ending and stress pattern) and whether such distributional information affects…
2. Assignment of element and isotope factors
International Nuclear Information System (INIS)
Schneider, R.A.
1984-01-01
Element and isotope factors are assigned in the NICS internal accounting system at the Exxon Fuel Fabrication Facility on the basis of coded information included on the material transfer documents. This paper explains more fully the manner in which NICS assigns these factors
3. Real life working shift assignment problem
Science.gov (United States)
Sze, San-Nah; Kwek, Yeek-Ling; Tiong, Wei-King; Chiew, Kang-Leng
2017-07-01
This study concerns about the working shift assignment in an outlet of Supermarket X in Eastern Mall, Kuching. The working shift assignment needs to be solved at least once in every month. Current approval process of working shifts is too troublesome and time-consuming. Furthermore, the management staff cannot have an overview of manpower and working shift schedule. Thus, the aim of this study is to develop working shift assignment simulation and propose a working shift assignment solution. The main objective for this study is to fulfill manpower demand at minimum operation cost. Besides, the day off and meal break policy should be fulfilled accordingly. Demand based heuristic is proposed to assign working shift and the quality of the solution is evaluated by using the real data.
4. Mars - robust automatic backbone assignment of proteins
International Nuclear Information System (INIS)
Jung, Young-Sang; Zweckstetter, Markus
2004-01-01
MARS a program for robust automatic backbone assignment of 13 C/ 15 N labeled proteins is presented. MARS does not require tight thresholds for establishing sequential connectivity or detailed adjustment of these thresholds and it can work with a wide variety of NMR experiments. Using only 13 C α / 13 C β connectivity information, MARS allows automatic, error-free assignment of 96% of the 370-residue maltose-binding protein. MARS can successfully be used when data are missing for a substantial portion of residues or for proteins with very high chemical shift degeneracy such as partially or fully unfolded proteins. Other sources of information, such as residue specific information or known assignments from a homologues protein, can be included into the assignment process. MARS exports its result in SPARKY format. This allows visual validation and integration of automated and manual assignment
5. Digital mammography
International Nuclear Information System (INIS)
Bick, Ulrich; Diekmann, Felix
2010-01-01
This state-of-the-art reference book provides in-depth coverage of all aspects of digital mammography, including detector technology, image processing, computer-aided diagnosis, soft-copy reading, digital workflow, and PACS. Specific advantages and disadvantages of digital mammography in comparison to screen-film mammography are thoroughly discussed. By including authors from both North America and Europe, the book is able to outline variations in the use, acceptance, and quality assurance of digital mammography between the different countries and screening programs. Advanced imaging techniques and future developments such as contrast mammography and digital breast tomosynthesis are also covered in detail. All of the chapters are written by internationally recognized experts and contain numerous high-quality illustrations. This book will be of great interest both to clinicians who already use or are transitioning to digital mammography and to basic scientists working in the field. (orig.)
6. Digital Insights
DEFF Research Database (Denmark)
Knudsen, Gry Høngsmark
, by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research...... and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising......This dissertation forwards the theory of digital consumer-response as a perspective to examine how digital media practices influence consumers’ response to advertising. Digital consumer-response is a development of advertising theory that encompasses how consumers employ their knowledge...
7. Digital Signage
OpenAIRE
Fischer, Karl Peter
2011-01-01
Digital Signage for in-store advertising at gas stations/retail stores in Germany: A field study Digital Signage networks provide a novel means of advertising with the advantage of easily changeable and highly customizable animated content. Despite the potential and increasing use of these media empirical research is scarce. In a field study at 8 gas stations (with integrated convenience stores) we studied the effect of digital signage advertising on sales for different products and servi...
8. Sports Digitalization
DEFF Research Database (Denmark)
Xiao, Xiao; Hedman, Jonas; Tan, Felix Ter Chian
2017-01-01
evolution, as digital technologies are increasingly entrenched in a wide range of sporting activities and for applications beyond mere performance enhancement. Despite such trends, research on sports digitalization in the IS discipline is surprisingly still nascent. This paper aims at establishing...... a discourse on sports digitalization within the discipline. Toward this, we first provide an understanding of the institutional characteristics of the sports industry, establishing its theoretical importance and relevance in our discipline; second, we reveal the latest trends of digitalization in the sports...
9. Digital native advertising: Practitioner perspectives and a research agenda
OpenAIRE
Harms, Bianca; Bijmolt, Tammo; Hoekstra, Janita
2018-01-01
Digital native advertising is a subtle form of digital advertising that is integrated closely with its context. Practitioners are increasingly assigning budgets to this advertising strategy. On the basis of 22 in-depth expert interviews with senior executives of advertising brands, publishing companies, and media agencies, this study provides new insights into the effectiveness of digital native advertising. We also shed light on factors in the field of content and context of digital native a...
10. Brown County, Wisconsin Digital Orthophotography
Data.gov (United States)
Federal Emergency Management Agency, Department of Homeland Security — Digital orthographic imagery datasets contain georeferenced images of the Earth's surface, collected by a sensor in which object displacement has been removed for...
11. Digital Audiobooks
DEFF Research Database (Denmark)
Have, Iben; Pedersen, Birgitte Stougaard
Audiobooks are rapidly gaining popularity with widely accessible digital downloading and streaming services. The paper is framing how the digital audiobook expands and changes the target groups for book publications and how it as an everyday activity is creating new reading experiences, places...
12. Digital TMI
Science.gov (United States)
Rios, Joseph
2012-01-01
Presenting the current status of the Digital TMI project to visiting members of the FAA Command Center. Digital TMI is an effort to store national-level traffic management initiatives in a standards-compliant manner. Work is funded by the FAA.
13. Digital displacements
DEFF Research Database (Denmark)
Pors, Anja Svejgaard
2014-01-01
In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co......-service, is a new task in public administration, where street level bureaucrats assist citizens in using the new digital solutions. The paper is based on a case study conducted primarily in a citizen service centre in Copenhagen, Denmark. Based on ethnography the paper gives an empirical account of the ongoing...
14. Digitized mammograms
International Nuclear Information System (INIS)
Bruneton, J.N.; Balu-Maestro, C.; Rogopoulos, A.; Chauvel, C.; Geoffray, A.
1988-01-01
Two observers conducted a blind evaluation of 100 mammography files, including 47 malignant cases. Films were read both before and after image digitization at 50 μm and 100 μm with the FilmDRSII. Digitization permitted better analysis of the normal anatomic structures and moderately improved diagnostic sensitivity. Searches for microcalcifications before and after digitization at 100 μm and 50 μm showed better analysis of anatomic structures after digitization (especially for solitary microcalcifications). The diagnostic benefit, with discovery of clustered microcalcifications, was more limited (one case at 100 μm, nine cases at 50 μm). Recognition of microcalcifications was clearly improved in dense breasts, which can benefit from reinterpretation after digitization at 50 μm rather 100μm
15. Postgraduate diploma collaborative assignment: Implications for ...
African Journals Online (AJOL)
Postgraduate diploma collaborative assignment: Implications for ESL students ... and collaborative teaching/learning model involving the major course convenors. ... The quality of the work and mood of all concerned improved tremendously.
16. Inferential backbone assignment for sparse data
International Nuclear Information System (INIS)
Vitek, Olga; Bailey-Kellogg, Chris; Craig, Bruce; Vitek, Jan
2006-01-01
This paper develops an approach to protein backbone NMR assignment that effectively assigns large proteins while using limited sets of triple-resonance experiments. Our approach handles proteins with large fractions of missing data and many ambiguous pairs of pseudoresidues, and provides a statistical assessment of confidence in global and position-specific assignments. The approach is tested on an extensive set of experimental and synthetic data of up to 723 residues, with match tolerances of up to 0.5 ppm for C α and C β resonance types. The tests show that the approach is particularly helpful when data contain experimental noise and require large match tolerances. The keys to the approach are an empirical Bayesian probability model that rigorously accounts for uncertainty in the data at all stages in the analysis, and a hybrid stochastic tree-based search algorithm that effectively explores the large space of possible assignments
17. Dynamic traffic assignment : genetic algorithms approach
Science.gov (United States)
1997-01-01
Real-time route guidance is a promising approach to alleviating congestion on the nations highways. A dynamic traffic assignment model is central to the development of guidance strategies. The artificial intelligence technique of genetic algorithm...
18. Statistical aspects of optimal treatment assignment
OpenAIRE
van der Linden, Willem J.
1980-01-01
The issues of treatment assignment is ordinarily dealt with within the framework of testing aptitude treatment interaction (ATI) hypothesis. ATI research mostly uses linear regression techniques, and an ATI exists when the aptitude treatment (AT) regression lines cross each other within the relevant interval of the aptitude variable. Consistent with this approach is the use of the points of interaction of AT regression lines as treatment-assignment rule. The replacement of such rules by monot...
19. On pole structure assignment in linear systems
Czech Academy of Sciences Publication Activity Database
Loiseau, J.-J.; Zagalak, Petr
2009-01-01
Roč. 82, č. 7 (2009), s. 1179-1192 ISSN 0020-7179 R&D Projects: GA ČR(CZ) GA102/07/1596 Institutional research plan: CEZ:AV0Z10750506 Keywords : linear systems * linear state feedback * pole structure assignment Subject RIV: BC - Control Systems Theory Impact factor: 1.124, year: 2009 http://library.utia.cas.cz/separaty/2009/AS/zagalak-on pole structure assignment in linear systems.pdf
20. Competitive Traffic Assignment in Road Networks
Directory of Open Access Journals (Sweden)
Krylatov Alexander Y.
2016-09-01
Full Text Available Recently in-vehicle route guidance and information systems are rapidly developing. Such systems are expected to reduce congestion in an urban traffic area. This social benefit is believed to be reached by imposing the route choices on the network users that lead to the system optimum traffic assignment. However, guidance service could be offered by different competitive business companies. Then route choices of different mutually independent groups of users may reject traffic assignment from the system optimum state. In this paper, a game theoretic approach is shown to be very efficient to formalize competitive traffic assignment problem with various groups of users in the form of non-cooperative network game with the Nash equilibrium search. The relationships between the Wardrop’s system optimum associated with the traffic assignment problem and the Nash equilibrium associated with the competitive traffic assignment problem are investigated. Moreover, some related aspects of the Nash equilibrium and the Wardrop’s user equilibrium assignments are also discussed.
1. Digital Surface and Terrain Models (DSM,DTM), The DTM associated with the Base Mapping Program consists of mass points and breaklines used primarily for ortho rectification. The DTM specifications included all breaklines for all hydro and transportation features and are the source for the TIPS (Tenn, Published in 2007, 1:4800 (1in=400ft) scale, Tennessee, OIR-GIS.
Data.gov (United States)
NSGIC State | GIS Inventory — Digital Surface and Terrain Models (DSM,DTM) dataset current as of 2007. The DTM associated with the Base Mapping Program consists of mass points and breaklines used...
2. Digital Ethics/Going Digital.
Science.gov (United States)
1996-01-01
Finds that the recent National Press Photographers Association code of ethics can serve as a model for any photography staff. Discusses how digital imaging is becoming commonplace in classrooms, due to decreasing costs and easier software. Explains digital terminology. Concludes that time saved in the darkroom and at the printer is now spent on…
International Nuclear Information System (INIS)
Coulomb, M.; Dal Soglio, S.; Pittet-Barbier, L.; Ranchoup, Y.; Thony, F.; Ferretti, G.; Robert, F.
1992-01-01
4. Becoming digital
DEFF Research Database (Denmark)
Pors, Anja Svejgaard
2015-01-01
. An ethnographic account of how digital reforms are implemented in practice shows how street-level bureaucrat’s classic tasks such as specialized casework are being reconfigured into educational tasks that promote the idea of “becoming digital”. In the paper, the author argues that the work of “becoming digital....... Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...
5. Digital Humanities
DEFF Research Database (Denmark)
Brügger, Niels
2016-01-01
, and preserving material to study, as an object of study in its own right, as an analytical tool, or for collaborating, and for disseminating results. The term "digital humanities" was coined around 2001, and gained currency within academia in the following years. However, computers had been used within......Digital humanities is an umbrella term for theories, methodologies, and practices related to humanities scholarship that use the digital computer as an integrated and essential part of its research and teaching activities. The computer can be used for establishing, finding, collecting...
6. Digital Snaps
DEFF Research Database (Denmark)
Sandbye, Mette; Larsen, Jonas
. Distance as the New Punctum / Mikko Villi -- pt. II. FAMILY ALBUMS IN TRANSITION -- ch. 4. How Digital Technologies Do Family Snaps, Only Better / Gillian Rose -- ch. 5. Friendship Photography: Memory, Mobility and Social Networking / Joanne Garde-Hansen -- ch. 6. Play, Process and Materiality in Japanese...... -- ch. 9. Retouch Yourself: The Pleasures and Politics of Digital Cosmetic Surgery / Tanya Sheehan -- ch. 10. Virtual Selves: Art and Digital Autobiography / Louise Wolthers -- ch. 11. Mobile-Media Photography: New Modes of Engagement / Michael Shanks and Connie Svabo....
7. Digital electronics
CERN Document Server
Morris, John
2013-01-01
An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th
DEFF Research Database (Denmark)
Zupancic, Tadeja; Verbeke, Johan; Achten, Henri
2016-01-01
Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media....... With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills....
International Nuclear Information System (INIS)
Zani, M.L.
2002-01-01
X-ray radiography is a very common technique used to check the homogeneity of a material or the inside of a mechanical part. Generally the radiation that goes through the material to check, produced an image on a sensitized film. This method requires time because the film needs to be developed, digital radiography has no longer this inconvenient. In digital radiography the film is replaced by digital data and can be processed as any computer file. This new technique is promising but its main inconvenient is that today its resolution is not so good as that of film radiography. (A.C.)
International Nuclear Information System (INIS)
Kusano, Shoichi
1993-01-01
Firstly, from an historic point of view, fundamental concepts on digital imaging were reviewed to provide a foundation for discussion of digital radiography. Secondly, this review summarized the results of ongoing research in computed radiography that replaces the conventional film-screen system with a photo-stimulable phosphor plate; and thirdly, image quality, radiation protection, and image processing techniques were discussed with emphasis on picture archiving and communication system environment as our final goal. Finally, future expansion of digital radiography was described based on the present utilization of computed tomography at the National Defense Medical College Hospital. (author) 60 refs
11. Flexible taxonomic assignment of ambiguous sequencing reads
Directory of Open Access Journals (Sweden)
Jansson Jesper
2011-01-01
Full Text Available Abstract Background To characterize the diversity of bacterial populations in metagenomic studies, sequencing reads need to be accurately assigned to taxonomic units in a given reference taxonomy. Reads that cannot be reliably assigned to a unique leaf in the taxonomy (ambiguous reads are typically assigned to the lowest common ancestor of the set of species that match it. This introduces a potentially severe error in the estimation of bacteria present in the sample due to false positives, since all species in the subtree rooted at the ancestor are implicitly assigned to the read even though many of them may not match it. Results We present a method that maps each read to a node in the taxonomy that minimizes a penalty score while balancing the relevance of precision and recall in the assignment through a parameter q. This mapping can be obtained in time linear in the number of matching sequences, because LCA queries to the reference taxonomy take constant time. When applied to six different metagenomic datasets, our algorithm produces different taxonomic distributions depending on whether coverage or precision is maximized. Including information on the quality of the reads reduces the number of unassigned reads but increases the number of ambiguous reads, stressing the relevance of our method. Finally, two measures of performance are described and results with a set of artificially generated datasets are discussed. Conclusions The assignment strategy of sequencing reads introduced in this paper is a versatile and a quick method to study bacterial communities. The bacterial composition of the analyzed samples can vary significantly depending on how ambiguous reads are assigned depending on the value of the q parameter. Validation of our results in an artificial dataset confirm that a combination of values of q produces the most accurate results.
12. Digital surfaces and hydrogeologic data for the Floridan aquifer system in Florida and in parts of Georgia, Alabama, and South Carolina
Science.gov (United States)
Bellino, Jason C.
2011-01-01
A digital dataset for the Floridan aquifer system in Florida and in parts of Georgia, Alabama, and South Carolina was developed from selected reports published as part of the Regional Aquifer-System Analysis (RASA) Program of the U.S. Geological Survey (USGS) in the 1980s. These reports contain maps and data depicting the extent and elevation of both time-stratigraphic and hydrogeologic units of which the aquifer system is composed, as well as data on hydrology, meteorology, and aquifer properties. The three primary reports used for this dataset compilation were USGS Professional Paper 1403-B (Miller, 1986), Professional Paper 1403-C (Bush and Johnston, 1988), and USGS Open-File Report 88-86 (Miller, 1988). Paper maps from Professional Papers 1403-B and 1403-C were scanned and georeferenced to the North American Datum of 1927 (NAD27) using the Lambert Conformal Conic projection (standard parallels 33 and 45 degrees, central longitude -96 degrees, central latitude 39 degrees). Once georeferenced, tracing of pertinent line features contained in each image (for example, contours and faults) was facilitated by specialized software using algorithms that automated much of the process. Resulting digital line features were then processed using standard geographic information system (GIS) software to remove artifacts from the digitization process and to verify and update attribute tables. The digitization process for polygonal features (for example, outcrop areas and unit extents) was completed by hand using GIS software.
13. First Trimester Fetal Gender Assignment by Ultrasound
Directory of Open Access Journals (Sweden)
Sabahattin Altunyurt
2010-03-01
Full Text Available Objective: To investigate the efficiency of genital tubercule angle on detecting fetal gender in first trimester by ultrasonography. Material-Method: Fetal sex assignment by ultrasound was carried out in 172 pregnancies at 11-13+6 weeks between 2007 June and 2007 December. Gestational age was determined by the measurement of crown-rump length (CRL. The ultrasound predictions were compared with actual sex at birth. Mid-sagittal planes of a section of the fetal genital tubercle were performed to identify the gender. Results: 155 of 172 patients’ data were achieved. The overall success rate was 92.3 % in sonographic assignment of fetal sex. The correct assignment rate in female fetuses was significantly higher than males (95.9 % - 88.8 % [p=0,001]. The correct identification of fetal sex improved with advancing gestational age from 89.3 % between 11-11+6 weeks, 92.5 % between 12-12+6 weeks and 93.4 % between 13-13+6 weeks (p=0,96. Conclusion: The fetal sex assignment by ultrasonography between 11-13+6 weeks had high success rate. The sensitivity of fetal sex assignment was not affected with fetus position and gestational age.
14. Digital Relationships
DEFF Research Database (Denmark)
Ledborg Hansen, Richard
-rich information and highly interesting communication are sky-high and rising. With a continuous increase in digitized communication follows a decrease in face-to-face encounters and our ability to engage in inter-personal relationships are suffering for it (Davis, 2013). The behavior described in this paper......-‐Jones, 2011) for increases in effectiveness and efficiency we indiscriminately embrace digital communication and digitized information dissemination with enthusiasm – at the risk of ignoring the potentially dark side of technology. However, technology also holds a promise for better understanding precisely...... for the same reasons – that the growing amount of digitized communication “out there” represents data waiting to be sifted, analyzed and decoded. In this paper “Facebook behavior” refers to a particular behavior characterized by presenting your self and representations of selected self in the hope of getting...
15. Digital Discretion
DEFF Research Database (Denmark)
Busch, Peter Andre; Zinner Henriksen, Helle
2018-01-01
discretion is suggested to reduce this footprint by influencing or replacing their discretionary practices using ICT. What is less researched is whether digital discretion can cause changes in public policy outcomes, and under what conditions such changes can occur. Using the concept of public service values......This study reviews 44 peer-reviewed articles on digital discretion published in the period from 1998 to January 2017. Street-level bureaucrats have traditionally had a wide ability to exercise discretion stirring debate since they can add their personal footprint on public policies. Digital......, we suggest that digital discretion can strengthen ethical and democratic values but weaken professional and relational values. Furthermore, we conclude that contextual factors such as considerations made by policy makers on the macro-level and the degree of professionalization of street...
16. Hydrography-driven coarsening of grid digital elevation models
Science.gov (United States)
Moretti, G.; Orlandini, S.
2017-12-01
A new grid coarsening strategy, denoted as hydrography-driven (HD) coarsening, is developed in the present study. The HD coarsening strategy is designed to retain the essential hydrographic features of surface flow paths observed in high-resolution digital elevation models (DEMs): (1) depressions are filled in the considered high-resolution DEM, (2) the obtained topographic data are used to extract a reference grid network composed of all surface flow paths, (3) the Horton order is assigned to each link of the reference grid network, and (4) within each coarse grid cell, the elevation of the point lying along the highest-order path of the reference grid network and displaying the minimum distance to the cell center is assigned to this coarse grid cell center. The capabilities of the HD coarsening strategy to provide consistent surface flow paths with respect to those observed in high-resolution DEMs are evaluated over a synthetic valley and two real drainage basins located in the Italian Alps and in the Italian Apennines. The HD coarsening is found to yield significantly more accurate surface flow path profiles than the standard nearest neighbor (NN) coarsening. In addition, the proposed strategy is found to reduce drastically the impact of depression-filling procedures in coarsened topographic data. The HD coarsening strategy is therefore advocated for all those cases in which the relief of the extracted drainage network is an important hydrographic feature. The figure below reports DEMs of a synthetic valley and extracted surface flow paths. (a) 10-m grid DEM displaying no depressions and extracted surface flow path (gray line). (b) 1-km grid DEM obtained from NN coarsening. (c) 1-km grid DEM obtained from NN coarsening plus depression-filling and extracted surface flow path (light blue line). (d) 1-km grid DEM obtained from HD coarsening and extracted surface flow path (magenta line).
17. Protein secondary structure assignment revisited: a detailed analysis of different assignment methods
Directory of Open Access Journals (Sweden)
de Brevern Alexandre G
2005-09-01
Full Text Available Abstract Background A number of methods are now available to perform automatic assignment of periodic secondary structures from atomic coordinates, based on different characteristics of the secondary structures. In general these methods exhibit a broad consensus as to the location of most helix and strand core segments in protein structures. However the termini of the segments are often ill-defined and it is difficult to decide unambiguously which residues at the edge of the segments have to be included. In addition, there is a "twilight zone" where secondary structure segments depart significantly from the idealized models of Pauling and Corey. For these segments, one has to decide whether the observed structural variations are merely distorsions or whether they constitute a break in the secondary structure. Methods To address these problems, we have developed a method for secondary structure assignment, called KAKSI. Assignments made by KAKSI are compared with assignments given by DSSP, STRIDE, XTLSSTR, PSEA and SECSTR, as well as secondary structures found in PDB files, on 4 datasets (X-ray structures with different resolution range, NMR structures. Results A detailed comparison of KAKSI assignments with those of STRIDE and PSEA reveals that KAKSI assigns slightly longer helices and strands than STRIDE in case of one-to-one correspondence between the segments. However, KAKSI tends also to favor the assignment of several short helices when STRIDE and PSEA assign longer, kinked, helices. Helices assigned by KAKSI have geometrical characteristics close to those described in the PDB. They are more linear than helices assigned by other methods. The same tendency to split long segments is observed for strands, although less systematically. We present a number of cases of secondary structure assignments that illustrate this behavior. Conclusion Our method provides valuable assignments which favor the regularity of secondary structure segments.
18. Writing Assignments that Promote Active Learning
Science.gov (United States)
Narayanan, M.
2014-12-01
Encourage students to write a detailed, analytical report correlating classroom discussions to an important historical event or a current event. Motivate students interview an expert from industry on a topic that was discussed in class. Ask the students to submit a report with supporting sketches, drawings, circuit diagrams and graphs. Propose that the students generate a complete a set of reading responses pertaining to an assigned topic. Require each student to bring in one comment or one question about an assigned reading. The assignment should be a recent publication in an appropriate journal. Have the students conduct a web search on an assigned topic. Ask them to generate a set of ideas that can relate to classroom discussions. Provide the students with a study guide. The study guide should provide about 10 or 15 short topics. Quiz the students on one or two of the topics. Encourage the students to design or develop some creative real-world examples based on a chapter discussed or a topic of interest. Require that students originate, develop, support and defend a viewpoint using a specifically assigned material. Make the students practice using or utilizing a set of new technical terms they have encountered in an assigned chapter. Have students develop original examples explaining the different terms. Ask the students to select one important terminology from the previous classroom discussions. Encourage the students to explain why they selected that particular word. Ask them to talk about the importance of the terminology from the point of view of their educational objectives and future career. Angelo, T. A. (1991). Ten easy pieces: Assessing higher learning in four dimensions. In T. A. Angelo (Ed.), Classroom research: Early lessons from success (pp. 17-31). New Directions for Teaching and Learning, No. 46. San Francisco: Jossey-Bass.
19. Grouping puts figure-ground assignment in context by constraining propagation of edge assignment.
Science.gov (United States)
Brooks, Joseph L; Brook, Joseph L; Driver, Jon
2010-05-01
Figure-ground organization involves the assignment of edges to a figural shape on one or the other side of each dividing edge. Established visual cues for edge assignment primarily concern relatively local rather than contextual factors. In the present article, we show that an assignment for a locally unbiased edge can be affected by an assignment of a remote contextual edge that has its own locally biased assignment. We find that such propagation of edge assignment from the biased remote context occurs only when the biased and unbiased edges are grouped. This new principle, whereby grouping constrains the propagation of figural edge assignment, emerges from both subjective reports and an objective short-term edge-matching task. It generalizes from moving displays involving grouping by common fate and collinearity, to static displays with grouping by similarity of edge-contrast polarity, or apparent occlusion. Our results identify a new contextual influence on edge assignment. They also identify a new mechanistic relation between grouping and figure-ground processes, whereby grouping between remote elements can constrain the propagation of edge assignment between those elements. Supplemental materials for this article may be downloaded from http://app.psychonomic-journals.org/content/supplemental.
20. Digital Collections, Digital Libraries & the Digitization of Cultural Heritage Information.
Science.gov (United States)
Lynch, Clifford
2002-01-01
Discusses digital collections and digital libraries. Topics include broadband availability; digital rights protection; content, both non-profit and commercial; digitization of cultural content; sustainability; metadata harvesting protocol; infrastructure; authorship; linking multiple resources; data mining; digitization of reference works;…
1. digital natives and digital immigrants
OpenAIRE
Cardina, Bruno; Francisco, Jerónimo; Reis, Pedro; trad. Silva, Fátima
2011-01-01
This article focuses on the generational gaps in school learning. Initially, we have tried to provide the framework in relation to the term digital native in order to understand the key aspects of the generation born after the advent and the global use of the Internet. They were found to be “multitasking” people, linked to technology and connectivity, as opposed to digital immigrants, born in an earlier period and seeking to adapt to the technological world. We also present some r...
2. Semi-infinite assignment and transportation games
NARCIS (Netherlands)
Timmer, Judith B.; Sánchez-Soriano, Joaqu´ın; Llorca, Navidad; Tijs, Stef; Goberna, Miguel A.; López, Marco A.
2001-01-01
Games corresponding to semi-infinite transportation and related assignment situations are studied. In a semi-infinite transportation situation, one aims at maximizing the profit from the transportation of a certain good from a finite number of suppliers to an infinite number of demanders. An
3. Capacity constrained assignment in spatial databases
DEFF Research Database (Denmark)
U, Leong Hou; Yiu, Man Lung; Mouratidis, Kyriakos
2008-01-01
large to fit in main memory. Motivated by this fact, we propose efficient algorithms for optimal assignment that employ novel edge-pruning strategies, based on the spatial properties of the problem. Additionally, we develop approximate (i.e., suboptimal) CCA solutions that provide a trade-off between...
4. Statistical aspects of optimal treatment assignment
NARCIS (Netherlands)
van der Linden, Willem J.
The issues of treatment assignment is ordinarily dealt with within the framework of testing aptitude treatment interaction (ATI) hypothesis. ATI research mostly uses linear regression techniques, and an ATI exists when the aptitude treatment (AT) regression lines cross each other within the relevant
5. Tabu search for target-radar assignment
DEFF Research Database (Denmark)
Hindsberger, Magnus; Vidal, Rene Victor Valqui
2000-01-01
In the paper the problem of assigning air-defense illumination radars to enemy targets is presented. A tabu search metaheuristic solution is described and the results achieved are compared to those of other heuristic approaches, implementation and experimental aspects are discussed. It is argued ...
6. Strategy-Proof Assignment Of Multiple Resources
DEFF Research Database (Denmark)
Erlanson, Albin; Szwagrzak, Karol
2015-01-01
We examine the strategy-proof allocation of multiple resources; an application is the assignment of packages of tasks, workloads, and compensations among the members of an organization. In the domain of multidimensional single-peaked preferences, we find that any allocation mechanism obtained by ...
7. Optimal Processor Assignment for Pipeline Computations
Science.gov (United States)
1991-10-01
the use of ratios: initially each task is assigned a procesbuor2 the remaining proceborb are distributed in proportion to the quantities f,(1), 1 < i...algorithmns. IEEE Trans. onl Parallel and Distributed Systemns, 1 (4):470-499, October 1990. [26] P. Al. Kogge. The Architeture of Pipelined Comnputers
8. Incentivized optimal advert assignment via utility decomposition
NARCIS (Netherlands)
Kelly, F.; Key, P.; Walton, N.
2014-01-01
We consider a large-scale Ad-auction where adverts are assigned over a potentially infinite number of searches. We capture the intrinsic asymmetries in information between advertisers, the advert platform and the space of searches: advertisers know and can optimize the average performance of their
9. A game theoretic approach to assignment problems
NARCIS (Netherlands)
Klijn, F.
2000-01-01
Game theory deals with the mathematical modeling and analysis of conflict and cooperation in the interaction of multiple decision makers. This thesis adopts two game theoretic methods to analyze a range of assignment problems that arise in various economic situations. The first method has as
10. Generalised Assignment Matrix Methodology in Linear Programming
Science.gov (United States)
Jerome, Lawrence
2012-01-01
Discrete Mathematics instructors and students have long been struggling with various labelling and scanning algorithms for solving many important problems. This paper shows how to solve a wide variety of Discrete Mathematics and OR problems using assignment matrices and linear programming, specifically using Excel Solvers although the same…
11. 7 CFR 1437.104 - Assigned production.
Science.gov (United States)
2010-01-01
...) Irrigation equipment is not capable of supplying adequate water to sustain the expected production of a... practice is not used. (7) For normal irrigated annual and biennial crops, the supply of available water at... determining losses under this section, assigned production will be used to offset the loss of production when...
12. Accounting for Sustainability: An Active Learning Assignment
Science.gov (United States)
Gusc, Joanna; van Veen-Dirks, Paula
2017-01-01
Purpose: Sustainability is one of the newer topics in the accounting courses taught in university teaching programs. The active learning assignment as described in this paper was developed for use in an accounting course in an undergraduate program. The aim was to enhance teaching about sustainability within such a course. The purpose of this…
13. Digital evidence
Directory of Open Access Journals (Sweden)
Lukić Tatjana
2012-01-01
Full Text Available Although computer makes human activities faster and easier, innovating and creating new forms of work and other kinds of activities, it also influenced the criminal activity. The development of information technology directly affects the development of computer forensics without which, it can not even imagine the discovering and proving the computer offences and apprehending the perpetrator. Information technology and computer forensic allows us to detect and prove the crimes committed by computer and capture the perpetrators. Computer forensics is a type of forensics which can be defined as a process of collecting, preserving, analyzing and presenting digital evidence in court proceedings. Bearing in mind, that combat against crime, in which computers appear as an asset or object of the offense, requires knowledge of digital evidence as well as specific rules and procedures, the author in this article specifically addresses the issues of digital evidence, forensic (computer investigation, specific rules and procedures for detecting, fixing and collecting digital evidence and use of this type of evidence in criminal proceedings. The author also delas with international standards regarding digital evidence and cyber-space investigation.
14. Digital watermark
Directory of Open Access Journals (Sweden)
Jasna Maver
2000-01-01
Full Text Available The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to different criteria. A digital watermark can be categorised as visible or invisible and as robust or fragile. In contrast to the visible watermark where a visible pattern or image is embedded into the original image, the invisible watermark does not change the visual appearance of the image. The existence of such a watermark can be determined only through a watermark ex¬traction or detection algorithm. The robust watermark is used for copyright protection, while the fragile watermark is designed for authentication and integrity verification of multimedia content. A watermark must be detectable or extractable to be useful. In some watermarking schemes, a watermark can be extracted in its exact form, in other cases, we can detect only whether a specific given watermarking signal is present in an image. Digital libraries, through which cultural institutions will make multimedia contents available, should support a wide range of service models for intellectual property protection, where digital watermarking may play an important role.
15. 47 CFR 74.602 - Frequency assignment.
Science.gov (United States)
2010-10-01
... transition to digital television in their market (DTV Transition), as set forth in §§ 73.622 through 73.625... CARS pickup stations inside a 50 km radius of the 100 television markets delineated in § 76.51 of this chapter. Outside a 50 km radius of the 100 television markets delineated in § 76.51 of this chapter...
16. Digital Creativity
DEFF Research Database (Denmark)
Petersson Brooks, Eva; Brooks, Anthony Lewis
2014-01-01
This paper reports on a study exploring the outcomes from children’s play with technology in early childhood learning practices. The paper addresses questions related to how digital technology can foster creativity in early childhood learning environments. It consists of an analysis of children......’s interaction with the KidSmart furniture focusing on digital creativity potentials and play values suggested by the technology. The study applied a qualitative approach and included125 children (aged three to five), 10 pedagogues, and two librarians. The results suggests that educators should sensitively...... consider intervening when children are interacting with technology, and rather put emphasize into the integration of the technology into the environment and to the curriculum in order to shape playful structures for children’s digital creativity....
International Nuclear Information System (INIS)
Rath, M.; Lissner, J.; Rienmueller, R.; Haendle, J.; Siemens A.G., Erlangen
1984-01-01
Using a prototype of an electronic, universal examination unit equipped with a special X-ray TV installation, spotfilm exposures and digital angiographies with high spatial resolution and wide-range contrast could be made in the clinic for the first time. With transvenous contrast medium injection, the clinical results of digital angiography show excellent image quality in the region of the carotids and renal arteries as well as the arteries of the extremities. The electronic series exposures have an image quality almost comparable to the quality obtained with cutfilm changers in conventional angiography. There are certain limitations due to the input field of 25 cm X-ray image intensified used. In respect of the digital angiography imaging technique, the electronic universal unit is fully suitable for clinical application. (orig.) [de
18. Digital photogrammetry
CERN Document Server
Egels, Yves
2003-01-01
Photogrammetry is the use of photography for surveying primarily and is used for the production of maps from aerial photographs. Along with remote sensing, it represents the primary means of generating data for Geographic Information Systems (GIS). As technology develops, it is becoming easier to gain access to it. The cost of digital photogrammetric workstations are falling quickly and these new tools are therefore becoming accessible to more and more users. Digital Photogrammetry is particularly useful as a text for graduate students in geomantic and is also suitable for people with a good basic scientific knowledge who need to understand photogrammetry, and who wish to use the book as a reference.
19. Digital Marketing
OpenAIRE
Jerry Wind; Vijay Mahajan
2002-01-01
The digital revolution has shaken marketing to its core with consumers being offered greater price transparency and often even the chance to dictate the price. What does pricing mean in a world in which customers propose their own prices (as at priceline.com) or buyers and sellers haggle independently in auctions (as at e-Bay)? The most significant changes in the digital marketing show the emergence of 'cyber consumers', the cyber business-to-business world and the changing reality of an incr...
20. Digital "X"
DEFF Research Database (Denmark)
Baiyere, Abayomi; Grover, Varun; Gupta, Alok
2017-01-01
Interest in using digital before existing research concepts seem to be on the rise in the IS field. This panel is positioned to explore what value lies in labelling our research as digital “x” as opposed to the well established IT “x” (where “x” can be strategy, infrastructure, innovation, artifa...... between this stream of research and existing research. Central among the expected output of the panel is the advancement of suggestions for future research and the critical pitfalls to avoid in doing so....
Science.gov (United States)
1986-01-01
System One, a digital radiography system, incorporates a reusable image medium (RIM) which retains an image. No film is needed; the RIM is read with a laser scanner, and the information is used to produce a digital image on an image processor. The image is stored on an optical disc. System allows the radiologist to "dial away" unwanted images to compare views on three screens. It is compatible with existing equipment and cost efficient. It was commercialized by a Stanford researcher from energy selective technology developed under a NASA grant.
2. Digital filters
CERN Document Server
Hamming, Richard W
1997-01-01
Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s
3. Digital voltmeter
International Nuclear Information System (INIS)
1976-01-01
The electrical voltage measuring equipment with digital display has been made. This equipment uses four digits display with single polarity measurement and integrating system. Pulses from the oscillator will be counted and converted to the staircase voltages, and compared to the voltage measured. When the balance is already achieved, the pulse will appear at the comparator circuit. This pulse will be used to trigger univibrator circuit. The univibrator output is used as signal for stopping the counting, and when reading time T already stops, the counting system will be reset. (authors)
4. Digital communication
CERN Document Server
Das, Apurba
2010-01-01
""Digital Communications"" presents the theory and application of the philosophy of Digital Communication systems in a unique but lucid form. This book inserts equal importance to the theory and application aspect of the subject whereby the authors selected a wide class of problems. The Salient features of the book are: the foundation of Fourier series, Transform and wavelets are introduces in a unique way but in lucid language; the application area is rich and resemblance to the present trend of research, as we are attached with those areas professionally; a CD is included which contains code
5. Digital literacies
CERN Document Server
Hockly, Nicky; Pegrum, Mark
2014-01-01
Dramatic shifts in our communication landscape have made it crucial for language teaching to go beyond print literacy and encompass the digital literacies which are increasingly central to learners' personal, social, educational and professional lives. By situating these digital literacies within a clear theoretical framework, this book provides educators and students alike with not just the background for a deeper understanding of these key 21st-century skills, but also the rationale for integrating these skills into classroom practice. This is the first methodology book to address not jus
6. Digital chest radiography system with amorphous selenium flat-panel detectors: qualitative and dosimetric comparison with a dedicated film-screen system
International Nuclear Information System (INIS)
Prato, Antonio; Fava Cesare; Ropolo, Roberto
2005-01-01
Purpose. To compare the quality and radiation dose of a conventional film-screen system and a digital system with amorphous selenium detectors in the study of the chest, by verifying overall performance and exposure levels for the main chest structures in patients of different sizes. Materials and methods. An analogic system (Chest Changer, Dupont, Day-light model 1000) and a digital system (Directray Rad 1000C, Hologic) were tested on a total of 1000 patients randomly assigned to one of two groups of 500 subjects.The patients were further subdivided according to BMI (Body Mass Index). Image quality was determined by two chest radiologists who evaluated eight anatomical structures. The entrance surface dose (skin-dose), calculated based on the exposure parameters, was taken as the patient dose. Results. Mean dose delivered was very similar for both techniques in the PA view (0.28 mGy), but it was greater in the LL projections obtained with the digital system (1.20 rnGy versus 0.83 mGy). The highest overall scores were assigned to 43% and 23.2% analogic radiograms and 64% and 70.2% digital radiograms, for the PA and LL projections respectively. The scores assigned to the various anatomical structures confirmed the better performance of the digital system in almost all of the regions considered. Conclusions. The mean quality of radiograms is definitely higher with the digital system, in particular in the LL projections, where the higher patient doses are counterbalanced by fewer repeated scans. The greater level of exposure in the digital system appears nonetheless tolerable on account of the greater informativeness and therefore diagnostic gain and also considering the possibilities for improving the system [it
7. Digital native advertising : Practitioner perspectives and a research agenda
NARCIS (Netherlands)
Harms, Bianca; Bijmolt, Tammo; Hoekstra, Janita
2017-01-01
Digital native advertising is a subtle form of digital advertising that is integrated closely with its context. Practitioners are increasingly assigning budgets to this advertising strategy. On the basis of 22 in-depth expert interviews with senior executives of advertising brands, publishing
8. Digital native advertising : Practitioner perspectives and a research agenda
NARCIS (Netherlands)
Harms, Bianca; Bijmolt, Tammo; Hoekstra, Janita
2018-01-01
Digital native advertising is a subtle form of digital advertising that is integrated closely with its context. Practitioners are increasingly assigning budgets to this advertising strategy. On the basis of 22 in-depth expert interviews with senior executives of advertising brands, publishing
9. Digital delicacies
OpenAIRE
Holley, Rose
2001-01-01
This presentation outlines the purpose and work of the newly appointed Digital Projects Librarian at the University of Auckland. It gives a brief overview of what digitisation is, the benefits, the stages of a digitisation project and also samples of interesting international digitisation projects and new University of Auckland Library Digitisation projects.
10. Digital Forensics
Science.gov (United States)
Harron, Jason; Langdon, John; Gonzalez, Jennifer; Cater, Scott
2017-01-01
The term forensic science may evoke thoughts of blood-spatter analysis, DNA testing, and identifying molds, spores, and larvae. A growing part of this field, however, is that of digital forensics, involving techniques with clear connections to math and physics. This article describes a five-part project involving smartphones and the investigation…
11. Digital Disruption
DEFF Research Database (Denmark)
Rosenstand, Claus Andreas Foss
det digitale domæne ud over det niveau, der kendetegner den nuværende debat, så præsenteres der ny viden om digital disruption. Som noget nyt udlægges Clayton Christens teori om disruptiv innovation med et særligt fokus på små organisationers mulighed for eksponentiel vækst. Specielt udfoldes...... forholdet mellem disruption og den stadig accelererende digitale udvikling i konturerne til ny teoridannelse om digital disruption. Bogens undertitel ”faretruende og fascinerende forandringer” peger på, at der er behov for en nuanceret debat om digital disruption i modsætning til den tone, der er slået an i...... videre kalder et ”disruption-råd”. Faktisk er rådet skrevet ind i 2016 regeringsgrundlaget for VLK-regeringen. Disruption af organisationer er ikke et nyt fænomen; men hastigheden, hvormed det sker, er stadig accelererende. Årsagen er den globale mega-trend: Digitalisering. Og derfor er specielt digital...
12. Digital books.
Science.gov (United States)
Wink, Diane M
2011-01-01
In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes digital books.
13. Digital forvaltning
DEFF Research Database (Denmark)
Remmen, Arne; Larsen, Torben; Mosgaard, Mette
2004-01-01
Større effektivitet, bedre service og mere demokrai er blot nogle af forventningerne til indførelse af digital forveltning i kommunerne. Kapitlet giver bland andet svar på spørgsmålene : Hvordan lever kommunerne op hertil i dagligdagen? hvilke virkemidler anvender de? Hvilke barrierer har der været...
14. Digital Methods
NARCIS (Netherlands)
Rogers, R.
2013-01-01
In Digital Methods, Richard Rogers proposes a methodological outlook for social and cultural scholarly research on the Web that seeks to move Internet research beyond the study of online culture. It is not a toolkit for Internet research, or operating instructions for a software package; it deals
15. Careerism, Committee Assignments and the Electoral Connection
OpenAIRE
Katz, Jonathan N.; Sala, Brian R.
1996-01-01
Most scholars agree that members of Congress are strongly motivated by their desire for reelection. This assumption implies that members of Congress adopt institutions, rules, and norms of behavior in part to serve their electoral interests. Direct tests of the electoral connection are rare, however, because significant, exogenous changes in the electoral environment are difficult to identify. We develop and test an electoral rationale for the norm of committee assignment "property rights...
16. Contact replacement for NMR resonance assignment.
Science.gov (United States)
Xiong, Fei; Pandurangan, Gopal; Bailey-Kellogg, Chris
2008-07-01
Complementing its traditional role in structural studies of proteins, nuclear magnetic resonance (NMR) spectroscopy is playing an increasingly important role in functional studies. NMR dynamics experiments characterize motions involved in target recognition, ligand binding, etc., while NMR chemical shift perturbation experiments identify and localize protein-protein and protein-ligand interactions. The key bottleneck in these studies is to determine the backbone resonance assignment, which allows spectral peaks to be mapped to specific atoms. This article develops a novel approach to address that bottleneck, exploiting an available X-ray structure or homology model to assign the entire backbone from a set of relatively fast and cheap NMR experiments. We formulate contact replacement for resonance assignment as the problem of computing correspondences between a contact graph representing the structure and an NMR graph representing the data; the NMR graph is a significantly corrupted, ambiguous version of the contact graph. We first show that by combining connectivity and amino acid type information, and exploiting the random structure of the noise, one can provably determine unique correspondences in polynomial time with high probability, even in the presence of significant noise (a constant number of noisy edges per vertex). We then detail an efficient randomized algorithm and show that, over a variety of experimental and synthetic datasets, it is robust to typical levels of structural variation (1-2 AA), noise (250-600%) and missings (10-40%). Our algorithm achieves very good overall assignment accuracy, above 80% in alpha-helices, 70% in beta-sheets and 60% in loop regions. Our contact replacement algorithm is implemented in platform-independent Python code. The software can be freely obtained for academic use by request from the authors.
17. An Ultimatum Game Approach to Billet Assignments
Science.gov (United States)
2015-09-01
time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed , and completing and reviewing this...treatments are needed for this investigation. To conserve the subject pool and meet the budget, we elected to pursue treatments that covered salient...across billets can be partially offset through compensating wages ( hedonic wages) and/or the potential of future superior assignments. In the
18. Protein secondary structure: category assignment and predictability
DEFF Research Database (Denmark)
Andersen, Claus A.; Bohr, Henrik; Brunak, Søren
2001-01-01
In the last decade, the prediction of protein secondary structure has been optimized using essentially one and the same assignment scheme known as DSSP. We present here a different scheme, which is more predictable. This scheme predicts directly the hydrogen bonds, which stabilize the secondary......-forward neural network with one hidden layer on a data set identical to the one used in earlier work....
19. Assignment and Correspondence Tracking System - Tactical / Operational Reporting
Data.gov (United States)
Social Security Administration — Reporting data store for the Assignment and Correspondence Tracking System (ACT). ACT automates the assignment and tracking of correspondence processing within the...
20. Tendencies of the digital newspapers in Peru
Directory of Open Access Journals (Sweden)
Dra. Lyudmyla Yezers´ka
2008-01-01
Full Text Available This article analyzes some of the tendencies of the development of the digital media in Peru. The results that are presented were obtained by means of a survey carried out to responsible people of the digital redactions of the national generalist newspapers that, when concluding the first decade of the existence of the online journalism in the country (1995-2005, had digital editions. From historical perspective, different stages of evolution and consolidation of the Peruvian daily editions in the Global Network have not had temporary clear definition. The media progressed at their own pace, depending among other factors –at the time of entry into the network, the staff assigned to the publication, and especially on the strength of the journalistic company and its policy regarding digital editing. With regard to the presence on the Internet, digital newspapers have shown a steady and numerous growth, over the first decade (1995-2005.
1. Comparison of the spatial landmark scatter of various 3D digitalization methods.
Science.gov (United States)
Boldt, Florian; Weinzierl, Christian; Hertrich, Klaus; Hirschfelder, Ursula
2009-05-01
The aim of this study was to compare four different three-dimensional digitalization methods on the basis of the complex anatomical surface of a cleft lip and palate plaster cast, and to ascertain their accuracy when positioning 3D landmarks. A cleft lip and palate plaster cast was digitalized with the SCAN3D photo-optical scanner, the OPTIX 400S laser-optical scanner, the Somatom Sensation 64 computed tomography system and the MicroScribe MLX 3-axis articulated-arm digitizer. First, four examiners appraised by individual visual inspection the surface detail reproduction of the three non-tactile digitalization methods in comparison to the reference plaster cast. The four examiners then localized the landmarks five times at intervals of 2 weeks. This involved simply copying, or spatially tracing, the landmarks from a reference plaster cast to each model digitally reproduced by each digitalization method. Statistical analysis of the landmark distribution specific to each method was performed based on the 3D coordinates of the positioned landmarks. Visual evaluation of surface detail conformity assigned the photo-optical digitalization method an average score of 1.5, the highest subjectively-determined conformity (surpassing computer tomographic and laser-optical methods). The tactile scanning method revealed the lowest degree of 3D landmark scatter, 0.12 mm, and at 1.01 mm the lowest maximum 3D landmark scatter; this was followed by the computer tomographic, photo-optical and laser-optical methods (in that order). This study demonstrates that the landmarks' precision and reproducibility are determined by the complexity of the reference-model surface as well as the digital surface quality and individual ability of each evaluator to capture 3D spatial relationships. The differences in the 3D-landmark scatter values and lowest maximum 3D-landmark scatter between the best and the worst methods showed minor differences. The measurement results in this study reveal that it
2. Creating a panorama of the heart with digital images.
Science.gov (United States)
Rosebrock, L
2000-01-01
Digital imaging offers new opportunities still being discovered by users. This article describes a technique that was created using a digital camera to photograph the entire surface of a rat heart. The technique may have other applications as well.
3. Digital Humanities and networked digital media
DEFF Research Database (Denmark)
Finnemann, Niels Ole
2014-01-01
This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...
4. Digital Materia
OpenAIRE
Lindgren, Marcus; Richey, Emma
2014-01-01
Med tankar från pedagogen Montessori och filosoferna Platon och Baudrillard har detta arbete behandlat frågor om datorn och dess betydelse för en grafiker. Frågeställningen formulerades efter hand och lydde tillslut: ”Hur kan materia te sig i digital form?” Forskningen resulterade i en hypotes för hur digital materia skulle födas i datorn: genom att blanda två uppsättningar av data, såsom två genuppsättningar tillsammans skapar en ny organism. Under produktionen utvecklades därmed en metod fö...
5. Becoming digital
DEFF Research Database (Denmark)
Pors, Anja Svejgaard
2015-01-01
government, and draws on empirical material generated through observations, field notes, interviews and policy documents. The material is documenting how service is performed by frontline agents in the ‘bureaucratic encounter’ with citizens, who needs assistance to use digital self-service in order to apply...... online for a public benefit. Findings: The paper shows that e-government technology changes the mode of professionalism in citizen service from service to support. The paper gives an empirical account of recent Danish digital reforms and shows how the reforms both enable and constrain the work...... of ‘becoming digital’ by frontline agents. Overall the street-level bureaucrat’s classical tasks such as specialized casework are being displaced into promoting and educational tasks. An implication of this is blurred distinctions between professional skills and personal competences of the frontline agent...
6. Digital resources
Directory of Open Access Journals (Sweden)
Redazione Reti Medievali (a cura di
2005-12-01
Full Text Available Bibliotheca Latinitatis Mediaevalis (circa VII sec. - XIV sec. IntraText Digital Library [01/06] Corpus Scriptorum Latinorum. A digital library of Latin literature by David Camden [01/06] Fonti disponibili online concernenti la vita religiosa medievale Rete Vitae Religiosae Mediaevalis Studia Conectens [01/06] Fuentes del Medievo Hispanico Instituto de Historia, Consejo Superior de Investigaciones Científicas [01/06] Latin Literature Forum Romanum [01/06] Ludovico Antonio Muratori, Dissertazioni sopra le antichità italiane, 1751 Biblioteca dei Classici Italiani di Giuseppe Bonghi [01/06] Medieval Latin The Latin Library [01/06] Médiévales Presses Universitaires de Vincennes - Revues.org [01/06] Regesta imperii Deutsche Kommission für die Bearbeitung der Regesta Imperii e.V. [01/06] Suda On Line Byzantine Lexicography [01/06
7. Digital teenagers
Directory of Open Access Journals (Sweden)
Rafael Conde Melguizo
2011-12-01
Full Text Available Espín, Manuel (Coord.(2011 Adolescentes Digitales. Revista Estudios de Juventud, Nº 92. Marzo 2011. INJUVE, Madrid."Adolescentes digitales" se nos muestra como una obra que pretende explorar desde distintos puntos de vista la realidad de la generación conocida como “nativos digitales” (Prensky, la generación actual de adolescentes que ha crecido con internet y el mundo digital como su entorno normal de socialización.
8. Digital Flora
OpenAIRE
Bunnell, Katie
2007-01-01
This research is concerned with developing a new business model for flexible small scale ceramic production that exploits the customisation capabilities of digital manufacturing technologies and the market potential and global connectivity of the world wide web. It is arguably of particular relevance to regional economic development in remote areas (Amin, Tomaney, Sabel) such as Cornwall where there is a culture of high quality small scale production, limited market and manufacturing opportun...
9. Symmetric Logic Synthesis with Phase Assignment
OpenAIRE
Benschop, N. F.
2001-01-01
Decomposition of any Boolean Function BF_n of n binary inputs into an optimal inverter coupled network of Symmetric Boolean functions SF_k (k \\leq n) is described. Each SF component is implemented by Threshold Logic Cells, forming a complete and compact T-Cell Library. Optimal phase assignment of input polarities maximizes local symmetries. The "rank spectrum" is a new BF_n description independent of input ordering, obtained by mapping its minterms onto an othogonal n \\times n grid of (transi...
10. 48 CFR 42.602 - Assignment and location.
Science.gov (United States)
2010-10-01
... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Assignment and location... Assignment and location. (a) A CACO may be assigned only when (1) the contractor has at least two locations..., or a full-time CACO may be assigned. In determining the location of the CACO, the responsible agency...
11. Testing the Effectiveness of Online Assignments in Theory of Finance
Science.gov (United States)
Batu, Michael; Bower, Nancy; Lun, Esmond; Sadanand, Asha
2018-01-01
The authors investigated the effectiveness of online versus paper assignments using final examination scores in three cohorts of theory of finance. In particular, two cohorts were exposed to online assignments while another cohort was exposed to traditional assignments. The central result is that exposure to online assignments robustly leads to…
12. The digital Emily project: achieving a photorealistic digital actor.
Science.gov (United States)
Alexander, Oleg; Rogers, Mike; Lambeth, William; Chiang, Jen-Yuan; Ma, Wan-Chun; Wang, Chuan-Chang; Debevec, Paul
2010-01-01
The Digital Emily Project uses advanced face scanning, character rigging, performance capture, and compositing to achieve one of the world's first photorealistic digital facial performances. The project scanned the geometry and reflectance of actress Emily O'Brien's face in 33 poses, showing different emotions, gaze directions, and lip formations in a light stage. These high-resolution scans-accurate to skin pores and fine wrinkles-became the basis for building a blendshape-based facial-animation rig whose expressions closely matched the scans. The blendshape rig drove displacement maps to add dynamic surface detail. A video-based facial animation system animated the face according to the performance in a reference video, and the digital face was tracked onto the video's motion and rendered under the same illumination. The result was a realistic 3D digital facial performance credited as one of the first to cross the "uncanny valley" between animated and fully human performances.
13. Assigned value improves memory of proper names.
Science.gov (United States)
Festini, Sara B; Hartley, Alan A; Tauber, Sarah K; Rhodes, Matthew G
2013-01-01
Names are more difficult to remember than other personal information such as occupations. The current research examined the influence of assigned point value on memory and metamemory judgements for names and occupations to determine whether incentive can improve recall of proper names. In Experiment 1 participants studied face-name and face-occupation pairs assigned 1 or 10 points, made judgements of learning, and were given a cued recall test. High-value names were recalled more often than low-value names. However, recall of occupations was not influenced by value. In Experiment 2 meaningless nonwords were used for both names and occupations. The name difficulty disappeared, and value influenced recall of both names and occupations. Thus value similarly influenced names and occupations when meaningfulness was held constant. In Experiment 3 participants were required to use overt rote rehearsal for all items. Value did not boost recall of high-value names, suggesting that differential processing could not be implemented to improve memory. Thus incentives may improve memory for proper names by motivating people to engage in selective rehearsal and effortful elaborative processing.
14. Digital citizens Digital nations: the next agenda
NARCIS (Netherlands)
A.W. (Bert) Mulder; M.W. (Martijn) Hartog
2015-01-01
DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and
15. METHOD FOR SOLVING FUZZY ASSIGNMENT PROBLEM USING MAGNITUDE RANKING TECHNIQUE
OpenAIRE
D. Selvi; R. Queen Mary; G. Velammal
2017-01-01
Assignment problems have various applications in the real world because of their wide applicability in industry, commerce, management science, etc. Traditional classical assignment problems cannot be successfully used for real life problem, hence the use of fuzzy assignment problems is more appropriate. In this paper, the fuzzy assignment problem is formulated to crisp assignment problem using Magnitude Ranking technique and Hungarian method has been applied to find an optimal solution. The N...
16. Digital fluorimeter
International Nuclear Information System (INIS)
Mello, H.A. de.
1980-11-01
The specifications of a digital fluorimeter. That with adequated analytical techniques permits to determine trace amounts of fluorescents materials in samples, are described. The fluorimeter is of the reflection type, and uses fluorescents lamps for the excitation and an optical system which is connected to a photomultiplyer machine and permits the measurement of the light intensity. In the case of IEN (Instituto de Engenharia Nuclear) the equipment is used for to determine the uranium content in sample materials to be exported. The precision of the instrument is about + - 1% in the scale of 0.1 which is the normally one used in the current researchs. (E.G.) [pt
17. Digital entrepreneurship
DEFF Research Database (Denmark)
Brem, Alexander; Richter, Chris; Kraus, Sascha
2017-01-01
comprising guided interviews with 14 companies from Germany, Austria and Switzerland provides detailed insights into different aspects of the sharing economy phenomenon. Our results make a direct contribution to sharing economy research, especially regarding the new business models of start-ups. Here, we...... find a clear difference between the relevance of economic and social orientation. The latter appears to be in higher demand among customers than entrepreneurs. The increasingly digitalized environment has led to a changed living situation characterized by urbanity, openness to new solutions, changed...
18. Focus: Digital
DEFF Research Database (Denmark)
Technology has been an all-important and defining element within the arts throughout the 20th century, and it has fundamentally changed the ways in which we produce and consume music. With this Focus we investigate the latest developments in the digital domain – and their pervasiveness and rapid...... production and reception of contemporary music and sound art. With ‘Digital’ we present four composers' very different answers to how technology impact their work. To Juliana Hodkinson it has become an integral part of her sonic writing. Rudiger Meyer analyses the relationships between art and design and how...
19. Structural Encoding of Static Single Assignment Form
DEFF Research Database (Denmark)
Gal, Andreas; Probst, Christian; Franz, Michael
2005-01-01
Static Single Assignment (SSA) form is often used as an intermediate representation during code optimization in Java Virtual Machines. Recently, SSA has successfully been used for bytecode verification. However, constructing SSA at the code consumer is costly. SSAbased mobile code transport formats...... Java bytecode. While the resulting bytecode sequence can still be directly executed by traditional Virtual Machines, our novel VM can infer SSA form and confirm its safety with virtually no overhead....... have been shown to eliminate this cost by shifting SSA creation to the code producer. These new formats, however, are not backward compatible with the established Java class-file format. We propose a novel approach to transport SSA information implicitly through structural code properties of standard...
20. Rationalization of some genetic anticodonic assignments
Science.gov (United States)
Lacey, J. C., Jr.; Hall, L. M.; Mullins, D. W., Jr.
1985-01-01
The hydrophobicity of most amino acids correlates well with that of their anticodon nucleotides, with Trp, Tyr, Ile, and Ser being the exceptions to this rule. Using previous data on hydrophobicity and binding constants, and new data on rates of esterification of polyadenylic acid with several N-acetylaminoacyl imidazolides, several of the anticodon assignments are rationalized. Chemical reasons are shown supporting the idea of the inclusion of the Ile in the catalog of biological amino acids late in the evolution, through a mutation of the existing tRNA and its aminoacyl-tRNA-synthetase. It was found that an addition of hexane increases the incorporation of hydrophobic Ac-Phe into poly-A, in support of the Fox (1965) and Oparin (1965) emphasis on the biogenetic importance of phase-separated systems.
1. Assignment of uncertainties to scientific data
International Nuclear Information System (INIS)
Froehner, F.H.
1994-01-01
Long-standing problems of uncertainty assignment to scientific data came into a sharp focus in recent years when uncertainty information ('covariance files') had to be added to application-oriented large libraries of evaluated nuclear data such as ENDF and JEF. Question arouse about the best way to express uncertainties, the meaning of statistical and systematic errors, the origin of correlation and construction of covariance matrices, the combination of uncertain data from different sources, the general usefulness of results that are strictly valid only for Gaussian or only for linear statistical models, etc. Conventional statistical theory is often unable to give unambiguous answers, and tends to fail when statistics is bad so that prior information becomes crucial. Modern probability theory, on the other hand, incorporating decision information becomes group-theoretic results, is shown to provide straight and unique answers to such questions, and to deal easily with prior information and small samples. (author). 10 refs
2. Automated digital magnetofluidics
Energy Technology Data Exchange (ETDEWEB)
Schneider, J; Garcia, A A; Marquez, M [Harrington Department of Bioengineering Arizona State University, Tempe AZ 85287-9709 (United States)], E-mail: [email protected]
2008-08-15
Drops can be moved in complex patterns on superhydrophobic surfaces using a reconfigured computer-controlled x-y metrology stage with a high degree of accuracy, flexibility, and reconfigurability. The stage employs a DMC-4030 controller which has a RISC-based, clock multiplying processor with DSP functions, accepting encoder inputs up to 22 MHz, provides servo update rates as high as 32 kHz, and processes commands at rates as fast as 40 milliseconds. A 6.35 mm diameter cylindrical NdFeB magnet is translated by the stage causing water drops to move by the action of induced magnetization of coated iron microspheres that remain in the drop and are attracted to the rare earth magnet through digital magnetofluidics. Water drops are easily moved in complex patterns in automated digital magnetofluidics at an average speed of 2.8 cm/s over a superhydrophobic polyethylene surface created by solvent casting. With additional components, some potential uses for this automated microfluidic system include characterization of superhydrophobic surfaces, water quality analysis, and medical diagnostics.
3. Automated digital magnetofluidics
Science.gov (United States)
Schneider, J.; Garcia, A. A.; Marquez, M.
2008-08-01
Drops can be moved in complex patterns on superhydrophobic surfaces using a reconfigured computer-controlled x-y metrology stage with a high degree of accuracy, flexibility, and reconfigurability. The stage employs a DMC-4030 controller which has a RISC-based, clock multiplying processor with DSP functions, accepting encoder inputs up to 22 MHz, provides servo update rates as high as 32 kHz, and processes commands at rates as fast as 40 milliseconds. A 6.35 mm diameter cylindrical NdFeB magnet is translated by the stage causing water drops to move by the action of induced magnetization of coated iron microspheres that remain in the drop and are attracted to the rare earth magnet through digital magnetofluidics. Water drops are easily moved in complex patterns in automated digital magnetofluidics at an average speed of 2.8 cm/s over a superhydrophobic polyethylene surface created by solvent casting. With additional components, some potential uses for this automated microfluidic system include characterization of superhydrophobic surfaces, water quality analysis, and medical diagnostics.
4. Solving multiconstraint assignment problems using learning automata.
Science.gov (United States)
Horn, Geir; Oommen, B John
2010-02-01
This paper considers the NP-hard problem of object assignment with respect to multiple constraints: assigning a set of elements (or objects) into mutually exclusive classes (or groups), where the elements which are "similar" to each other are hopefully located in the same class. The literature reports solutions in which the similarity constraint consists of a single index that is inappropriate for the type of multiconstraint problems considered here and where the constraints could simultaneously be contradictory. This feature, where we permit possibly contradictory constraints, distinguishes this paper from the state of the art. Indeed, we are aware of no learning automata (or other heuristic) solutions which solve this problem in its most general setting. Such a scenario is illustrated with the static mapping problem, which consists of distributing the processes of a parallel application onto a set of computing nodes. This is a classical and yet very important problem within the areas of parallel computing, grid computing, and cloud computing. We have developed four learning-automata (LA)-based algorithms to solve this problem: First, a fixed-structure stochastic automata algorithm is presented, where the processes try to form pairs to go onto the same node. This algorithm solves the problem, although it requires some centralized coordination. As it is desirable to avoid centralized control, we subsequently present three different variable-structure stochastic automata (VSSA) algorithms, which have superior partitioning properties in certain settings, although they forfeit some of the scalability features of the fixed-structure algorithm. All three VSSA algorithms model the processes as automata having first the hosting nodes as possible actions; second, the processes as possible actions; and, third, attempting to estimate the process communication digraph prior to probabilistically mapping the processes. This paper, which, we believe, comprehensively reports the
5. Digital Humanities
DEFF Research Database (Denmark)
Nielsen, Hans Jørn
2015-01-01
overgangen fra trykkekultur til digital kultur. For det første problemstillingen omkring digitalisering af litterær kulturarv med fokus på kodning og tagging af teksten samt organisering i hypertekststrukturer. For det andet reorganiseringen af det digitale dokument i dataelementer og database. For det......Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH......, der betragter DH som forbundet med "making" og "building" af digitale objekter og former. Dette kan også karakteriseres som DH som praktisk-produktiv vending. Artiklen har valgt tre typer af digitalisering. De er valgt ud fra, at de skal repræsentere forskellige måder at håndtere digitaliseringen på...
6. USDA-FSA-APFO Digital Ortho Mosaic
Data.gov (United States)
Federal Emergency Management Agency, Department of Homeland Security — Digital orthographic imagery datasets contain georeferenced images of the Earth's surface, collected by a sensor in which object displacement has been removed for...
DEFF Research Database (Denmark)
Precht, H; Gerke, O; Rosendahl, K
2012-01-01
BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults....... OBJECTIVE: To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. MATERIALS AND METHODS: A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR...... with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. RESULTS: Optimal image-quality was maintained at a dose...
8. Fokus: Digital
DEFF Research Database (Denmark)
2014-01-01
i det digitale domæne – udviklinger, der foregår hastigt og er gennemgribende, og som derfor kræver et nærmere blik på forholdet mellem kunsten og teknologien. Komponistens forståelse af sin metier udfordres – samtidig med at befæstede ideer om kunstværket møder modstand fra nye mediemæssige...... sammenhænge og fra forandrede distributionsformer. Dette betyder ændrede betingelser for både produktion og reception af kunstmusik og lydkunst. Med Digital tager vi udgangspunkt i fire komponisters meget forskellige bud på hvordan teknologien spiller en rolle i arbejdet. Juliana Hodkinson beskriver hvordan...
9. Dual earners’ willingness to accept an international assignment.
NARCIS (Netherlands)
van der Velde, E.G.; Bossink, C.J.H.; Jansen, P.G.W.
2005-01-01
Multinational organisations experience difficulties in finding managers willing to accept international assignments. This study has therefore focused on factors that can predict males' and females' willingness to accept international assignments, or to follow their partners on international
10. Efficient Mechanisms to Allocate Assignment Incentives in the Navy
National Research Council Canada - National Science Library
Nimon, R. W; Hall, Ricky D; Zaki, Hossam
2005-01-01
.... All assignments, however, may not necessarily be voluntary. These assignments (jobs) have been labeled as "hard to fill" by Navy leadership, and the Navy has implemented market-based, cash stipends to attract Sailors to these jobs...
11. Comparing Examples: WebAssign versus Textbook
Science.gov (United States)
Richards, Evan; Polak, Jeff; Hardin, Ashley; Risley, John, , Dr.
2005-11-01
Research shows students can learn from worked examples.^1 This pilot study compared two groups of students' performance (10 each) in solving physics problems. One group had access to interactive examples^2 released in WebAssign^3, while the other group had access to the counterpart textbook examples. Verbal data from students in problem solving sessions was collected using a think aloud protocol^4 and the data was analyzed using Chi's procedures.^5 An explanation of the methodology and results will be presented. Future phases of this pilot study based upon these results will also be discussed. ^1Atkinson, R.K., Derry, S.J., Renkl A., Wortham, D. (2000). Learning from Examples: Instructional Principles from the Worked Examples Research'', Review of Educational Research, vol. 70, n. 2, pp. 181-214. ^2Serway, R.A. & Faughn, J.S. (2006). College Physics (7^th ed.). Belmont, CA: Thomson Brooks/Cole. ^3 see www.webassign.net ^4 Ericsson, K.A. & Simon, H.A. (1984). Protocol Analysis: Verbal Reports as Data. Cambridge, Massachusetts: The MIT Press. ^5 Chi, Michelene T.H. (1997). `Quantifying Qualitative Analyses of Verbal Data: A Practical Guide,'' The Journal of the Learning Sciences, vol. 6, n. 3, pp. 271-315.
12. SCRAED - Simple and Complex Random Assignment in Experimental Designs
OpenAIRE
Alferes, Valentim R.
2009-01-01
SCRAED is a package of 37 self-contained SPSS syntax files that performs simple and complex random assignment in experimental designs. For between-subjects designs, SCRAED includes simple random assignment (no restrictions, forced equal sizes, forced unequal sizes, and unequal probabilities), block random assignment (simple and generalized blocks), and stratified random assignment (no restrictions, forced equal sizes, forced unequal sizes, and unequal probabilities). For within-subject...
13. Digital work in a digitally challenged organization
NARCIS (Netherlands)
Davison, R.M.; Ou, Carol
Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the
14. Optimal assignment of incoming flights to baggage carousels at airports
DEFF Research Database (Denmark)
Barth, Torben C.
The problem considered in this report is an assignment problem occurring at airports. This problem concerns the assignment of baggage carousels in baggage claim halls to arriving aircraft (baggage carousel assignment problem). This is a highly dynamic problem since disruptions frequently occur du...... and in general is a substantial support in decision making....
15. Computational Aspects of Assigning Agents to a Line
DEFF Research Database (Denmark)
Aziz, Haris; Hougaard, Jens Leth; Moreno-Ternero, Juan D.
2017-01-01
-egalitarian assignments. The approach relies on an algorithm which is shown to be faster than general purpose algorithms for the assignment problem. We also extend the approach to probabilistic assignments and explore the computational features of existing, as well as new, methods for this setting....
16. Computational aspects of assigning agents to a line
DEFF Research Database (Denmark)
Aziz, Haris; Hougaard, Jens Leth; Moreno-Ternero, Juan D.
2017-01-01
-egalitarian assignments. The approach relies on an algorithm which is shown to be faster than general purpose algorithms for the assignment problem. We also extend the approach to probabilistic assignments and explore the computational features of existing, as well as new, methods for this setting....
17. The Presentation Assignment: Creating Learning Opportunities for Diverse Student Populations.
Science.gov (United States)
Spencer, Brenda H.; Bartle-Angus, Kathryn
2000-01-01
Finds the presentation assignment to be an effective method of providing students with the opportunity to apply the literacy skills they are learning in ways that are personally meaningful. Describes the presentation assignment framework and provides an example of an assignment that required students to analyze and interpret works of literature…
18. Assignment Procedures in the Air Force Procurement Management Information System.
Science.gov (United States)
Ward, Joe H., Jr.; And Others
An overview is presented of the procedure for offering jobs in the Air Force Procurement Management Information System (PROMIS), an assignment system which makes possible the use of human resources research findings to improve individual personnel assignments. A general framework for viewing personnel assignment systems is presented; then job…
19. 75 FR 55354 - Delegation of Authority and Assignment of Responsibilities
Science.gov (United States)
2010-09-10
... DEPARTMENT OF LABOR Office of the Secretary Delegation of Authority and Assignment of Responsibilities Secretary's Order 3-2010 Subject: Delegation of Authority and Assignment of Responsibilities to... Secretary to enforce sections 18A and 18B of the FLSA. 4. Delegation of Authority and Assignment of...
20. 75 FR 55355 - Delegation of Authority and Assignment of Responsibility
Science.gov (United States)
2010-09-10
... DEPARTMENT OF LABOR Office of the Secretary Delegation of Authority and Assignment of Responsibility Secretary's Order 4-2010 Subject: Delegation of Authority and Assignment of Responsibility to the... delegations and assignments in full force and effect, except as expressly modified herein. 4. Delegation of...
1. A Computerized Approach to Trickle-Process, Random Assignment.
Science.gov (United States)
Braucht, G. Nicholas; Reichardt, Charles S.
1993-01-01
Procedures for implementing random assignment with trickle processing and ways they can be corrupted are described. A computerized method for implementing random assignment with trickle processing is presented as a desirable alternative in many situations and a way of protecting against threats to assignment validity. (SLD)
2. 7 CFR 900.106 - Assignment of mediator.
Science.gov (United States)
2010-01-01
... 7 Agriculture 8 2010-01-01 2010-01-01 false Assignment of mediator. 900.106 Section 900.106 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing... Assignment of mediator. The Director of the Division shall assign a mediator, from the group designated by...
3. A property of assignment type mixed integer linear programming problems
NARCIS (Netherlands)
Benders, J.F.; van Nunen, J.A.E.E.
1982-01-01
In this paper we will proof that rather tight upper bounds can be given for the number of non-unique assignments that are achieved after solving the linear programming relaxation of some types of mixed integer linear assignment problems. Since in these cases the number of splitted assignments is
4. One of My Favorite Assignments: Automated Teller Machine Simulation.
Science.gov (United States)
Oberman, Paul S.
2001-01-01
Describes an assignment for an introductory computer science class that requires the student to write a software program that simulates an automated teller machine. Highlights include an algorithm for the assignment; sample file contents; language features used; assignment variations; and discussion points. (LRW)
5. Student generated assignments about electrical circuits in a computer simulation
NARCIS (Netherlands)
Vreman-de Olde, Cornelise; de Jong, Anthonius J.M.
2004-01-01
In this study we investigated the design of assignments by students as a knowledge-generating activity. Students were required to design assignments for 'other students' in a computer simulation environment about electrical circuits. Assignments consisted of a question, alternatives, and feedback on
6. Evaluation of flexural strength and surface properties of prepolymerized CAD/CAM PMMA-based polymers used for digital 3D complete dentures.
Science.gov (United States)
Arslan, Mustafa; Murat, Sema; Alp, Gulce; Zaimoglu, Ali
2018-01-01
7. A Pilot Study on the Influence of Facial Expression on Measurements in Three-Dimensional Digital Surfaces of the Face in Infants With Cleft Lip and Palate
DEFF Research Database (Denmark)
Hermann, Nuno Vibe; Darvann, Tron Andre; Larsen, P.
2016-01-01
of deformation in three selected regions were determined: nose (mean, 1 mm; maximum = 3 mm); cleft region (mean, 2 mm; maximum = 5 mm); chin region (mean, 5 mm; maximum = 12 mm). Analysis indicated that introduction of a formalized review of images could reduce these errors by a factor of 2. Conclusions......Objective Three-dimensional surface imaging is an increasingly popular modality for face measurements in infants with cleft lip and palate. Infants are noncompliant toward producing specific facial expressions, and selecting the appropriate moment of acquisition is challenging. The objective...... was to estimate amount and spatial distribution of deformation of the face due to facial expression in infants with cleft lip and palate and provide recommendations for an improved acquisition protocol, including a method of quality control in terms of obtaining images with true neutral expression. Material...
8. USNA DIGITAL FORENSICS LAB
Data.gov (United States)
Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab MissionEstablish and maintain a Digital...
9. Can We Teach Digital Natives Digital Literacy?
Science.gov (United States)
Ng, Wan
2012-01-01
In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…
10. Vibration measurements by pulsed digital holographic endoscopy
Science.gov (United States)
Schedin, Staffan; Pedrini, Giancarlo; Perez-Lopez, Carlos; Mendoza Santoyo, Fernando
2005-02-01
Digital holographic interferometry in combination with a flexible fiber endoscope allows high precision measurements of deformations on hidden objects surfaces, inside cavities and objects with small access apertures. A digital holographic endoscopy system is described with a frequency-doubled, twin oscillator Q-switched pulsed Nd:YAG laser as light source. A sequence of digital hologram pairs are recorded with a maximum repetition rate of 260 ms. Each digital hologram is captured at separate video frames of a CCD-camera. The time separation between the laser pulses from each cavity can be set in the range from 50 to 500 μs. The digital holograms are transferred to a PC via a frame grabber and evaluated quantitatively by the Fourier transform method. The resulting phase fringe pattern has the information needed to evaluate quantitatively the amount of the deformation. Experimental results of vibration measurements of hidden mechanical and biological object surfaces are presented. The quality of the results obtained by mechanical object surfaces is usually higher than for biological surfaces. This can be explained easily by the fact that a biological surface is much more complex than a mechanical surface in the sense that some parts of the surface may reflect the light well whereas other parts may absorb the light. Also, biological surfaces are translucent, which means that part of the light may enter inside the sample where it may be absorbed or reflected.
11. Batch metadata assignment to archival photograph collections using facial recognition software
Directory of Open Access Journals (Sweden)
Kyle Banerjee
2013-07-01
Full Text Available Useful metadata is essential to giving individual meaning and value within the context of a greater image collection as well as making them more discoverable. However, often little information is available about the photos themselves, so adding consistent metadata to large collections of digital and digitized photographs is a time consuming process requiring highly experienced staff. By using facial recognition software, staff can identify individuals more quickly and reliably. Knowledge of individuals in photos helps staff determine when and where photos are taken and also improves understanding of the subject matter. This article demonstrates simple techniques for using facial recognition software and command line tools to assign, modify, and read metadata for large archival photograph collections.
12. Automation of block assignment planning using a diagram-based scenario modeling method
Directory of Open Access Journals (Sweden)
Hwang In Hyuck
2014-03-01
Full Text Available Most shipbuilding scheduling research so far has focused on the load level on the dock plan. This is be¬cause the dock is the least extendable resource in shipyards, and its overloading is difficult to resolve. However, once dock scheduling is completed, making a plan that makes the best use of the rest of the resources in the shipyard to minimize any additional cost is also important. Block assignment planning is one of the midterm planning tasks; it assigns a block to the facility (factory/shop or surface plate that will actually manufacture the block according to the block characteristics and current situation of the facility. It is one of the most heavily loaded midterm planning tasks and is carried out manu¬ally by experienced workers. In this study, a method of representing the block assignment rules using a diagram was su¬ggested through analysis of the existing manual process. A block allocation program was developed which automated the block assignment process according to the rules represented by the diagram. The planning scenario was validated through a case study that compared the manual assignment and two automated block assignment results.
13. Automation of block assignment planning using a diagram-based scenario modeling method
Directory of Open Access Journals (Sweden)
In Hyuck Hwang
2014-03-01
Full Text Available Most shipbuilding scheduling research so far has focused on the load level on the dock plan. This is because the dock is the least extendable resource in shipyards, and its overloading is difficult to resolve. However, once dock scheduling is completed, making a plan that makes the best use of the rest of the resources in the shipyard to minimize any additional cost is also important. Block assignment planning is one of the midterm planning tasks; it assigns a block to the facility (factory/shop or surface plate that will actually manufacture the block according to the block characteristics and current situation of the facility. It is one of the most heavily loaded midterm planning tasks and is carried out manually by experienced workers. In this study, a method of representing the block assignment rules using a diagram was suggested through analysis of the existing manual process. A block allocation program was developed which automated the block assignment process according to the rules represented by the diagram. The planning scenario was validated through a case study that compared the manual assignment and two automated block assignment results.
14. WDM Optical Access Network for Full-Duplex and Reconfigurable Capacity Assignment Based on PolMUX Technique
Directory of Open Access Journals (Sweden)
Jose Mora
2014-12-01
Full Text Available We present a novel bidirectional WDM-based optical access network featuring reconfigurable capacity assignment. The architecture relies on the PolMUX technique allowing a compact, flexible, and bandwidth-efficient router in addition to source-free ONUs and color-less ONUs for cost/complexity minimization. Moreover, the centralized architecture contemplates remote management and control of polarization. High-quality transmission of digital signals is demonstrated through different routing scenarios where all channels are dynamically assigned in both downlink and uplink directions.
15. Investigation of body and udder skin surface temperature differentials as an early indicator of mastitis in Holstein Friesian crossbred cows using digital infrared thermography technique
Directory of Open Access Journals (Sweden)
M. Sathiyabarathi
2016-12-01
Full Text Available Aim: The objective of this study was to investigate the ability of infrared thermography (IRT technique and its interrelationship with conventional mastitis indicators for the early detection of mastitis in Holstein Friesian (HF crossbred cows. Materials and Methods: A total of 76 quarters of lactating HF crossbred (Bos indicus × Bos taurus cows (n=19 were monitored for body temperature (i.e., eye temperature and udder skin surface temperature (USST before milking using forward-looking infrared (FLIR i5 camera. Milk samples were collected from each quarter and screened for mastitis using Somatic Cell Count (SCC, Electrical Conductivity (EC, and California mastitis test. Thermographic images were analyzed using FLIR Quick Report 1.2 image analysis software. Data on body and USST were compiled and analyzed statistically using SPSS 16.0 and Sigmaplot 11. Results: The mean±standard deviation (SD body (37.23±0.08°C and USST (37.22±0.04°C of non-mastitic cow did not differ significantly; however, the mean USST of the mastitis-affected quarters were significantly higher than the body temperature and USST of unaffected quarters (p37.61°C. Conclusion: It is concluded that infrared thermal imaging technique could be used as a potential noninvasive, quick cowside diagnostic technique for screening and early detection of SCM and clinical mastitis in crossbred cows.
16. Digital produktion
DEFF Research Database (Denmark)
Bogen sætter fokus på digital produktion, som er en stærk læringsform, der faciliterer elevernes læreprocesser og kvalificerer elevernes faglige læringsresultater. Det sker når lærerne udarbejder didaktiske rammedesign, hvor eleverne arbejder selvstændigt inden for dette rammedesign, og hvor mål og...... procesevaluering stilladserer elevernes faglige proces. I digitale produktionsprocesser arbejder eleverne iterativt, de udvikler ejerskab til produktionen og fastholder selv deres læreprocesser. It’s multimodalitet, elevernes kollaborative tilgange, videndeling mellem eleverne og elevernes uformelle lege- og...... elevernes digitale produktion er lærernes didaktiske rammesætning og stilladserende tilgange. Her lægger lærerne op til, at eleverne som didaktiske designere i relation til rammesætningen skal organisere og planlægge deres læreprocesser, inddrages i målsætning, evaluering og valg af digitale ressourcer...
17. Digital dannelse
DEFF Research Database (Denmark)
Bundsgaard, Jeppe
2012-01-01
I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et dannelsesspørgs......I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et...... dannelsesspørgsmål knyttet til it. Hvad er egentlig digital dannelse? Og hvad betyder det for danskfaget?...
18. Digital forensics digital evidence in criminal investigations
CERN Document Server
Marshall, Angus McKenzie
2009-01-01
The vast majority of modern criminal investigations involve some element of digital evidence, from mobile phones, computers, CCTV and other devices. Digital Forensics: Digital Evidence in Criminal Investigations provides the reader with a better understanding of how digital evidence complements "traditional" scientific evidence and examines how it can be used more effectively and efficiently in a range of investigations. Taking a new approach to the topic, this book presents digital evidence as an adjunct to other types of evidence and discusses how it can be deployed effectively in s
19. Thermophysical modeling for high-resolution digital terrain models
Science.gov (United States)
Pelivan, I.
2018-04-01
A method is presented for efficiently calculating surface temperatures for highly resolved celestial body shapes. A thorough investigation of the necessary conditions leading to reach model convergence shows that the speed of surface temperature convergence depends on factors such as the quality of initial boundary conditions, thermal inertia, illumination conditions, and resolution of the numerical depth grid. The optimization process to shorten the simulation time while increasing or maintaining the accuracy of model results includes the introduction of facet-specific boundary conditions such as pre-computed temperature estimates and pre-evaluated simulation times. The individual facet treatment also allows for assigning other facet-specific properties such as local thermal inertia. The approach outlined in this paper is particularly useful for very detailed digital terrain models in combination with unfavorable illumination conditions such as little to no sunlight at all for a period of time as experienced locally on comet 67P/Churyumov-Gerasimenko. Possible science applications include thermal analysis of highly resolved local (landing) sites experiencing seasonal, environment and lander shadowing. In combination with an appropriate roughness model, the method is very suitable for application to disk-integrated and disk-resolved data. Further applications are seen where the complexity of the task has led to severe shape or thermophysical model simplifications such as in studying surface activity or thermal cracking.
20. Digital platforms as enablers for digital transformation
DEFF Research Database (Denmark)
Hossain, Mokter; Lassen, Astrid Heidemann
transformation is crucial. This study aims at exploring how organizations are driven towards transformation in various ways to embrace digital platforms for ideas, technologies, and knowledge. It shows the opportunities and challenges digital platforms bring in organizations. It also highlights underlying......Digital platforms offer new ways for organizations to collaborate with the external environment for ideas, technologies, and knowledge. They provide new possibilities and competence but they also bring new challenges for organizations. Understanding the role of these platforms in digital...... mechanisms and potential outcomes of various digital platforms. The contribution of the submission is valuable for scholars to understand and further explore this area. It provides insight for practitioners to capture value through digital platforms and accelerate the pace of organizations’ digital...
1. Iowa Bedrock Surface Elevation
Data.gov (United States)
Iowa State University GIS Support and Research Facility — This Digital Elevation Model (DEM) of the bedrock surface elevation in Iowa was compiled using all available data, principally information from GEOSAM, supplemented...
2. Digital readout alpha survey instrument
International Nuclear Information System (INIS)
Jacobs, M.E.
1976-01-01
A prototype solid-state digital readout alpha particle survey instrument has been designed and constructed. The meter incorporates a Ludlum alpha scintillator as a detector, digital logic circuits for control and timing, and a Digilin counting module with reflective liquid crystal display. The device is used to monitor alpha radiation from a surface. Sample counts are totalized over 10-second intervals and displayed digitally in counts per minute up to 19,999. Tests over source samples with counts to 15,600 cpm have shown the device to be rapid, versatile and accurate. The instrument can be fabricated in one man-week and requires about \$835 in material costs. A complete set of drawings is included
3. H. Sapiens Digital: From Digital Immigrants and Digital Natives to Digital Wisdom
Science.gov (United States)
Prensky, Marc
2009-01-01
As we move further into the 21st century, the digital native/digital immigrant paradigm created by Marc Prensky in 2001 is becoming less relevant. In this article, Prensky suggests that we should focus instead on the development of what he calls "digital wisdom." Arguing that digital technology can make us not just smarter but truly wiser, Prensky…
4. Dual beam vidicon digitizer
International Nuclear Information System (INIS)
Evans, T.L.
1976-01-01
A vidicon waveform digitizer which can simultaneously digitize two independent signals has been developed. Either transient or repetitive waveforms can be digitized with this system. A dual beam oscilloscope is used as the signal input device. The light from the oscilloscope traces is optically coupled to a television camera, where the signals are temporarily stored prior to digitizing
5. Raman spectroscopy of adsorbed water in clays: first attempt at band assignment
Energy Technology Data Exchange (ETDEWEB)
Ligny, Dominique de; Guillaud, Emmanuel [Institut Lumiere Matiere, CNRS, Universite Lyon 1, 12 rue Ada Byron, 69622 Villeurbanne (France); Gailhanou, Helene; Blanc, Philippe [BRGM, Service D3E, 3 avenue Claude Guillemin, 45000 Orleans (France)
2013-07-01
Raman spectroscopy can be a useful tool to determine water content within clays, or even in highly saturated solutions. The following assignment is proposed for the OH region of SAz-2: the two large bands at 3260 and 3475 cm{sup -1} are assigned to water in pores, the first one to water molecules coordinated to the interlayer cations, and the second one to structural Al-OH groups The band at 3600 cm{sup -1} is therefore more likely related to adsorbed water on the clay surface. Simple intensity ratios of these different bands give good estimates of water content. (authors)
6. Enabling Digital Literacy
DEFF Research Database (Denmark)
Ryberg, Thomas; Georgsen, Marianne
2010-01-01
There are some tensions between high-level policy definitions of “digital literacy” and actual teaching practice. We need to find workable definitions of digital literacy; obtain a better understanding of what digital literacy might look like in practice; and identify pedagogical approaches, which...... support teachers in designing digital literacy learning. We suggest that frameworks such as Problem Based Learning (PBL) are approaches that enable digital literacy learning because they provide good settings for engaging with digital literacy. We illustrate this through analysis of a case. Furthermore......, these operate on a meso-level mediating between high-level concepts of digital literacy and classroom practice....
International Nuclear Information System (INIS)
Cappelle, A.
2016-01-01
8. Digital Sensor Technology
Energy Technology Data Exchange (ETDEWEB)
Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas
2013-07-01
The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.
9. Digital preservation for heritages
CERN Document Server
Lu, Dongming
2011-01-01
""Digital Preservation for Heritages: Technologies and Applications"" provides a comprehensive and up-to-date coverage of digital technologies in the area of cultural heritage preservation, including digitalization, research aiding, conservation aiding, digital exhibition, and digital utilization. Processes, technical frameworks, key technologies, as well as typical systems and applications are discussed in the book. It is intended for researchers and students in the fields of computer science and technology, museology, and archaeology. Dr. Dongming Lu is a professor at College of Computer Sci
10. WebAssign: Assessing Your Students' Understanding Continuously
Science.gov (United States)
Risley, John S.
1999-11-01
Motivating students to learn is a constant challenge for faculty. Technology can play a significant role. One such solution is WebAssign — a web-based homework system that offers new teaching and learning opportunities for educators and their students. WebAssign delivers, collects, grades, and records customized homework assignments over the Internet. Students get immediate feedback with credit and instructors can implement "Just-in-Time" teaching. In this talk, I will describe how assignments can be generated with different numerical values for each question, giving each student a unique problem to solve. This feature encourages independent thinking with the benefit of collaborative learning. Example assignments taken from textbook questions and intellectually engaging Java applet simulations will be shown. Studies and first-hand experience on the educational impact of using WebAssign will also be discussed.
11. A new digital land mobile satellite system
Science.gov (United States)
Schneider, Philip
A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.
12. A probabilistic approach for validating protein NMR chemical shift assignments
International Nuclear Information System (INIS)
Wang Bowei; Wang, Yunjun; Wishart, David S.
2010-01-01
It has been estimated that more than 20% of the proteins in the BMRB are improperly referenced and that about 1% of all chemical shift assignments are mis-assigned. These statistics also reflect the likelihood that any newly assigned protein will have shift assignment or shift referencing errors. The relatively high frequency of these errors continues to be a concern for the biomolecular NMR community. While several programs do exist to detect and/or correct chemical shift mis-referencing or chemical shift mis-assignments, most can only do one, or the other. The one program (SHIFTCOR) that is capable of handling both chemical shift mis-referencing and mis-assignments, requires the 3D structure coordinates of the target protein. Given that chemical shift mis-assignments and chemical shift re-referencing issues should ideally be addressed prior to 3D structure determination, there is a clear need to develop a structure-independent approach. Here, we present a new structure-independent protocol, which is based on using residue-specific and secondary structure-specific chemical shift distributions calculated over small (3-6 residue) fragments to identify mis-assigned resonances. The method is also able to identify and re-reference mis-referenced chemical shift assignments. Comparisons against existing re-referencing or mis-assignment detection programs show that the method is as good or superior to existing approaches. The protocol described here has been implemented into a freely available Java program called 'Probabilistic Approach for protein Nmr Assignment Validation (PANAV)' and as a web server (http://redpoll.pharmacy.ualberta.ca/PANAVhttp://redpoll.pharmacy.ualberta.ca/PANAV) which can be used to validate and/or correct as well as re-reference assigned protein chemical shifts.
13. Ant Colony Algorithm and Simulation for Robust Airport Gate Assignment
Directory of Open Access Journals (Sweden)
Hui Zhao
2014-01-01
Full Text Available Airport gate assignment is core task for airport ground operations. Due to the fact that the departure and arrival time of flights may be influenced by many random factors, the airport gate assignment scheme may encounter gate conflict and many other problems. This paper aims at finding a robust solution for airport gate assignment problem. A mixed integer model is proposed to formulate the problem, and colony algorithm is designed to solve this model. Simulation result shows that, in consideration of robustness, the ability of antidisturbance for airport gate assignment scheme has much improved.
14. Cognitive Hacking and Digital Government: Digital Identity
OpenAIRE
Paul Thompson
2004-01-01
Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation syst...
15. Digital Materialisms: Frameworks for Digital Media Studies
OpenAIRE
Casemajor, Nathalie
2015-01-01
Since the 1980s, digital materialism has received increasing interest in the field of media studies. Materialism as a theoretical paradigm assumes that all things in the world are tied to physical processes and matter. Yet within digital media studies, the understanding of what should be the core object of a materialist analysis is debated. This paper proposes to untangle some of the principal theoretical propositions that compose the field of digital materialism. It outlines six frameworks t...
International Nuclear Information System (INIS)
Borovikov, N.V.; Kosinov, G.A.; Fedorov, Yu.N.
1989-01-01
Portable transportable digital beta radiometer providing for measuring beta-decay radionuclide specific activity in the range from 5x10 -9 up to 10 -6 Cu/kg (Cu/l) with error of ±25% is designed and introduced into commercial production for determination of volume and specific water and food radioactivity. The device specifications are given. Experience in the BETA radiometer application under conditions of the Chernobyl' NPP 30-km zone has shown that it is convenient for measuring specific activity of the order of 10 -8 Cu/kg, and application of a set of different beta detectors gives an opportunity to use it for surface contamination measurement in wide range of the measured value
17. Digital multilayer tomography
International Nuclear Information System (INIS)
Dueber, C.; Klose, K.J.; Thelen, M.
1991-01-01
With digital multilayer tomography a sequence of projection images is recorded by an image intensifier television system and stored as digital data during a linear run of a layer sequence. Using this data record, tomograms of the examined body region can be computed for any layer thickness by shifts and superimposition of the single projections later at a digital workstation. The qualities of digital and conventional tomograms are basically comparable. A drawback of digital tomography is its lower local resolution (512 x 512 image matrix), advantages are a lower radiation exposure, a shorter patient examination time, and the facilities of digital image processing (later processing, archive setup, transmission). (orig.) [de
18. Experience with digital mammography
Directory of Open Access Journals (Sweden)
G. P. Korzhenkova
2011-01-01
Full Text Available The use of digital techniques in mammography has become a last step for completing the process of digitization in diagnostic imaging. It is assumed that such a spatial decision will be required for digital mammography, as well as for high-resolution intensifying screen-film systems used in conventional mammography and that the digital techniques will be limited by the digitizer pixel size on detecting minor structures, such as microcalcifications. The introduction of digital technologies in mammography involves a tight control over an image and assures its high quality.
19. Logic of the digital
CERN Document Server
2015-01-01
Building a foundational understanding of the digital, Logic of the Digital reveals a unique digital ontology. Beginning from formal and technical characteristics, especially the binary code at the core of all digital technologies, Aden Evens traces the pathways along which the digital domain of abstract logic encounters the material, human world. How does a code using only 0s and 1s give rise to the vast range of applications and information that constitutes a great and growing portion of our world? Evens' analysis shows how any encounter between the actual and the digital must cross an ontolo
20. Negotiating Languages and Cultures: Enacting Translingualism through a Translation Assignment
Science.gov (United States)
Kiernan, Julia; Meier, Joyce; Wang, Xiqiao
2016-01-01
This collaborative project explores the affordances of a translation assignment in the context of a learner-centered pedagogy that places composition students' movement among languages and cultures as both a site for inquiry and subject of analysis. The translation assignment asks students to translate scholarly articles or culture stories from…
1. On some special cases of the restricted assignment problem
NARCIS (Netherlands)
Wang, C. (Chao); R.A. Sitters (René)
2016-01-01
textabstractWe consider some special cases of the restricted assignment problem. In this scheduling problem on parallel machines, any job j can only be assigned to one of the machines in its given subset Mj of machines. We give an LP-formulation for the problem with two job sizes and show that it
2. 25 CFR 225.33 - Assignment of minerals agreements.
Science.gov (United States)
2010-04-01
... 25 Indians 1 2010-04-01 2010-04-01 false Assignment of minerals agreements. 225.33 Section 225.33 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS OIL AND GAS, GEOTHERMAL, AND SOLID MINERALS AGREEMENTS Minerals Agreements § 225.33 Assignment of minerals agreements. An...
3. On the Use of Writing Assignments in Intermediate Microeconomic Theory
Science.gov (United States)
O'Neill, Patrick B.
2009-01-01
A typical writing assignment in upper level required courses is a term paper. However many economics majors, particularly those in business schools, need to develop skill at writing shorter pieces. In this paper I describe numerous examples of shorter writing assignments that I have incorporated into an Intermediate Microeconomic Theory course.…
4. 75 FR 55352 - Delegation of Authorities and Assignment of Responsibilities
Science.gov (United States)
2010-09-10
... DEPARTMENT OF LABOR Office of the Secretary Delegation of Authorities and Assignment of Responsibilities Secretary's Order 5-2010 Subject: Delegation of Authorities and Assignment of Responsibilities to... rather than the Administrator, WHD (see also Secretary's Order 3-2010). 5. Delegations of Authority and...
5. 7 CFR 1900.5 - Assignment of cases.
Science.gov (United States)
2010-01-01
... 7 Agriculture 12 2010-01-01 2010-01-01 false Assignment of cases. 1900.5 Section 1900.5 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS... REGULATIONS GENERAL Delegations of Authority § 1900.5 Assignment of cases. The State Director may, in writing...
6. Students' Evaluation of Writing Assignments in an Abnormal Psychology Course.
Science.gov (United States)
Procidano, Mary E.
1991-01-01
Presents a study in which students in an abnormal psychology class rated the usefulness of drafts for two writing assignments. Reports that a research proposal was more effective than a case study in generating interest in psychology and opportunity for creativity. Concludes that writing assignments should reflect important aspects of a…
7. 14 CFR 1245.109 - Assignment of title to NASA.
Science.gov (United States)
2010-01-01
... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Assignment of title to NASA. 1245.109... INTELLECTUAL PROPERTY RIGHTS Patent Waiver Regulations § 1245.109 Assignment of title to NASA. (a) The instrument of waiver set forth in § 1245.115(c) shall be voided by NASA with respect to the domestic title to...
8. 32 CFR 644.396 - Assignment of personnel to administer.
Science.gov (United States)
2010-07-01
... 32 National Defense 4 2010-07-01 2010-07-01 true Assignment of personnel to administer. 644.396... PROPERTY REAL ESTATE HANDBOOK Disposal Predisposal Action § 644.396 Assignment of personnel to administer... responsible representative to each installation, or group of installations, to act under his staff supervision...
9. Exogenous spatial attention influences figure-ground assignment.
Science.gov (United States)
Vecera, Shaun P; Flevaris, Anastasia V; Filapek, Joseph C
2004-01-01
In a hierarchical stage account of vision, figure-ground assignment is thought to be completed before the operation of focal spatial attention. Results of previous studies have supported this account by showing that unpredictive, exogenous spatial precues do not influence figure-ground assignment, although voluntary attention can influence figure-ground assignment. However, in these studies, attention was not summoned directly to a region in a figure-ground display. In three experiments, we addressed the relationship between figure-ground assignment and visuospatial attention. In Experiment 1, we replicated the finding that exogenous precues do not influence figure-ground assignment when they direct attention outside of a figure-ground stimulus. In Experiment 2, we demonstrated that exogenous attention can influence figure-ground assignment if it is directed to one of the regions in a figure-ground stimulus. In Experiment 3, we demonstrated that exogenous attention can influence figure-ground assignment in displays that contain a Gestalt figure-ground cue; this result suggests that figure-ground processes are not entirely completed prior to the operation of focal spatial attention. Exogenous spatial attention acts as a cue for figure-ground assignment and can affect the outcome of figure-ground processes.
10. Parentage assignment of progeny in mixed milt fertilization of ...
African Journals Online (AJOL)
2011-06-13
Jun 13, 2011 ... individuals. Overall, 98.8% of progeny were assigned to their parents using Family Assignment. Program (FAP). Selection of hyper-variable microsatellites in Caspian brown trout to identify unique alleles was effective for unambiguous parentage determination and estimation of genetic diversity in this study.
11. Genetics of traffic assignment models for strategic transport planning
NARCIS (Netherlands)
Bliemer, M.C.J.; Raadsen, M.P.H.; Brederode, L.J.N.; Bell, M.G.H.; Wismans, Luc Johannes Josephus; Smith, M.J.
2016-01-01
This paper presents a review and classification of traffic assignment models for strategic transport planning purposes by using concepts analogous to genetics in biology. Traffic assignment models share the same theoretical framework (DNA), but differ in capability (genes). We argue that all traffic
12. Scaffolding Assignments and Activities for Undergraduate Research Methods
Science.gov (United States)
Fisher, Sarah; Justwan, Florian
2018-01-01
This article details assignments and lessons created for and tested in research methods courses at two different universities, a large state school and a small liberal arts college. Each assignment or activity utilized scaffolding. Students were asked to push beyond their comfort zone while utilizing concrete and/or creative examples,…
13. A Poster Assignment Connects Information Literacy and Writing Skills
Science.gov (United States)
Waters, Natalie
2015-01-01
This paper describes the implementation of a poster assignment in a writing and information literacy course required for undergraduate Life Sciences and Environmental Biology majors with the Faculty of Agricultural and Environmental Sciences at McGill University. The assignment was introduced in response to weaknesses identified through course…
14. Personnel shift assignment: Existence conditions and network models
NARCIS (Netherlands)
van den Berg, Jeroen P.; van den Berg, J.P.; Panton, David M.
1994-01-01
The personnel scheduling problem is known to be a five-stage process in which the final stage involves the assignment of shifts to the days worked in the schedule. This paper discusses the existence conditions for both continuous and forward rotating shift assignments and heuristic network
15. 28 CFR 545.23 - Inmate work/program assignment.
Science.gov (United States)
2010-07-01
... community living area, unless the pretrial inmate has signed a waiver of his or her right not to work (see... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Inmate work/program assignment. 545.23... WORK AND COMPENSATION Inmate Work and Performance Pay Program § 545.23 Inmate work/program assignment...
16. Automating Formative and Summative Feedback for Individualised Assignments
Science.gov (United States)
Hamilton, Ian Robert
2009-01-01
Purpose: The purpose of this paper is to report on the rationale behind the use of a unique paper-based individualised accounting assignment, which automated the provision to students of immediate formative and timely summative feedback. Design/methodology/approach: As students worked towards completing their assignment, the package provided…
17. submission of art studio-based assignments: students experience
African Journals Online (AJOL)
PUBLICATIONS1
are reluctant to complete their studio assignments on time are critically ... tative and qualitative data, derived from survey and interviews were used to ... is therefore exploratory and studio based. It ... mogenous group of students who report pro- ... Assignment management .... The analyses in this study are based on data.
18. 13 CFR 500.210 - Assignment or transfer of loans.
Science.gov (United States)
2010-01-01
... has the effect of distributing the risks of the credit among other Lenders if: (i) Neither the loan... be modified, assigned, conveyed, sold or otherwise transferred by the Lender, in whole or in part... assignment or transfer of less than 100 percent of a Lender's interest in the Loan Documents and Guarantee...
19. English Digital Dictionaries as Valuable Blended Learning Tools for Palestinian College Students
Science.gov (United States)
2015-01-01
Digital technology has become an indispensable aspect of foreign language learning around the globe especially in the case of college students who are often required to finish extensive reading assignments within a limited time period. Such pressure calls for the use of efficient tools such as digital dictionaries to help them achieve their…
20. The Effect of Digital Video Games on EFL Students' Language Learning Motivation
Science.gov (United States)
2017-01-01
The study examined the effect of a commercial digital video game on high school students' language learning motivation. Participants were 241 male students randomly assigned to one of the following three treatments: Readers, who intensively read the game's story; Players, who played the digital video game; and Watchers, who watched two classmates…
1. Comic Relief: Graduate Students Address Multiple Meanings for Technology Integration with Digital Comic Creation
Science.gov (United States)
Sockman, Beth Rajan; Sutton, Rhonda; Herrmann, Michele
2016-01-01
This study determined the usefulness of digital comic creation with 77 graduate students in a teacher technology course. Students completed an assigned reading and created digital comics that addressed technology integration concerns in the schools and society. Using practical action research, 77 student-created comics were analyzed. The findings…
2. Designing Internet research assignments: building a framework for instructor collaboration
Directory of Open Access Journals (Sweden)
David Ward
2000-01-01
Full Text Available Internet knowledge is increasing steadily among instructors in the academic world. As courses incorporate more instructional technology, traditional undergraduate research assignments are adapting to reflect the changing world of information and information access. New library assignments reflect this shift as well, with term papers and research projects asking students to use Web sites as an information resource, in addition to the standard literature of periodicals and monographs. But the many pitfalls the library profession has learned in its own metamorphosis during the past decade are often repeated in these newer course assignments. The authors in this paper present a framework for librarians to interact with instructors to incorporate Internet resources into traditional term paper and research assignments. They suggest a framework for creating sample assignments librarians can take to campus instructional units, to show the teaching community at large what the library profession has learned from first-hand experience.
3. GENERAL ISSUES CONCERNING THE ASSIGNMENT OF SOCIAL PARTS
Directory of Open Access Journals (Sweden)
Stela Mihăilescu
2012-11-01
Full Text Available By means of the present study, we try to offer a thorough image and an analysis concerning the assignment mode of social parts within a company having limited liability. The assignment of social parts is free and unrestricted except for the cases provided by article 202, paragraph 2 from Law no. 31/ 1990- the law of commercial companies with further modifications and completions and the ones provided in OUG no. 54/ 2010 concerning some measures for fighting fiscal evasion. By means of the assignment operation a transmission is made up by an assignment of social parts contract towards one or more already associated persons in the company or towards other individual or legal persons who are going to obtain the associate quality. The principle governing any assignment is the one of goods circulation freedom, a freedom restricted only by the public order and imperative judicial norms.
4. Cybercrime, digital forensics and jurisdiction
CERN Document Server
Chawki, Mohamed; Khan, Mohammad Ayoub; Tyagi, Sapna
2015-01-01
The purpose of law is to prevent the society from harm by declaring what conduct is criminal, and prescribing the punishment to be imposed for such conduct. The pervasiveness of the internet and its anonymous nature make cyberspace a lawless frontier where anarchy prevails. Historically, economic value has been assigned to visible and tangible assets. With the increasing appreciation that intangible data disseminated through an intangible medium can possess economic value, cybercrime is also being recognized as an economic asset. The Cybercrime, Digital Forensics and Jurisdiction disseminate knowledge for everyone involved with understanding and preventing cybercrime - business entities, private citizens, and government agencies. The book is firmly rooted in the law demonstrating that a viable strategy to confront cybercrime must be international in scope.
5. Coastal California Digital Imagery
Data.gov (United States)
National Oceanic and Atmospheric Administration, Department of Commerce — This digital ortho-imagery dataset is a survey of coastal California. The project area consists of approximately 3774 square miles. The project design of the digital...
6. Digital rectal exam
Science.gov (United States)
... this page: //medlineplus.gov/ency/article/007069.htm Digital rectal exam To use the sharing features on this page, please enable JavaScript. A digital rectal exam is an examination of the lower ...
7. Digital dannelse til gymnasieeleverne
DEFF Research Database (Denmark)
Kaarsted, Thomas; Holch Andersen, Knud
2012-01-01
Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene.......Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene....
8. Basic digital signal processing
CERN Document Server
Lockhart, Gordon B
1985-01-01
Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.
9. Digital Inkjet Textile Printing
OpenAIRE
Wang, Meichun
2017-01-01
Digital inkjet textile printing is an emerging technology developed with the rise of the digital world. It offers a possibility to print high-resolution images with unlimited color selection on fabrics. Digital inkjet printing brings a revolutionary chance for the textile printing industry. The history of textile printing shows the law how new technology replaces the traditional way of printing. This indicates the future of digital inkjet textile printing is relatively positive. Differen...
10. Digital Language Death
Science.gov (United States)
Kornai, András
2013-01-01
Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide. PMID:24167559
11. Digital language death.
Directory of Open Access Journals (Sweden)
András Kornai
Full Text Available Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide.
12. Digital Imaging. Chapter 16
Energy Technology Data Exchange (ETDEWEB)
Clunie, D. [CoreLab Partners, Princeton (United States)
2014-09-15
The original means of recording X ray images was a photographic plate. Nowadays, all medical imaging modalities provide for digital acquisition, though globally, the use of radiographic film is still widespread. Many modalities are fundamentally digital in that they require image reconstruction from quantified digital signals, such as computed tomography (CT) and magnetic resonance imaging (MRI)
13. Preparing collections for digitization
CERN Document Server
Bulow, Anna E
2010-01-01
Most libraries, archives and museums are confronting the challenges of providing digital access to their collections. This guide offers guidance covering the end-to-end process of digitizing collections, from selecting records for digitization to choosing suppliers and equipment and dealing with documents that present individual problems.
14. Digital voltage discriminator
International Nuclear Information System (INIS)
Zhou Zhicheng
1992-01-01
A digital voltage discriminator is described, which is synthesized by digital comparator and ADC. The threshold is program controllable with high stability. Digital region of confusion is approximately equal to 1.5 LSB. This discriminator has a single channel analyzer function model with channel width of 1.5 LSB
15. Playtesting the Digital Playground
DEFF Research Database (Denmark)
Majgaard, G.; Jessen, Carsten
2009-01-01
Being able to be absorbed in play in the digital playground is motivating for children who are used digital computer games. The children can play and exercise outdoors while using the same literacy as in indoor digital games. This paper presents a new playground product where an outdoor playgroun...
16. Routine digital pathology workflow: The Catania experience
Directory of Open Access Journals (Sweden)
Filippo Fraggetta
2017-01-01
Full Text Available Introduction: Successful implementation of whole slide imaging (WSI for routine clinical practice has been accomplished in only a few pathology laboratories worldwide. We report the transition to an effective and complete digital surgical pathology workflow in the pathology laboratory at Cannizzaro Hospital in Catania, Italy. Methods: All (100% permanent histopathology glass slides were digitized at ×20 using Aperio AT2 scanners. Compatible stain and scanning slide racks were employed to streamline operations. eSlide Manager software was bidirectionally interfaced with the anatomic pathology laboratory information system. Virtual slide trays connected to the two-dimensional (2D barcode tracking system allowed pathologists to confirm that they were correctly assigned slides and that all tissues on these glass slides were scanned. Results: Over 115,000 glass slides were digitized with a scan fail rate of around 1%. Drying glass slides before scanning minimized them sticking to scanner racks. Implementation required introduction of a 2D barcode tracking system and modification of histology workflow processes. Conclusion: Our experience indicates that effective adoption of WSI for primary diagnostic use was more dependent on optimizing preimaging variables and integration with the laboratory information system than on information technology infrastructure and ensuring pathologist buy-in. Implementation of digital pathology for routine practice not only leveraged the benefits of digital imaging but also creates an opportunity for establishing standardization of workflow processes in the pathology laboratory.
17. Heuristic for Task-Worker Assignment with Varying Learning Slopes
Directory of Open Access Journals (Sweden)
Wipawee Tharmmaphornphilas
2010-04-01
Full Text Available Fashion industry has variety products, so the multi-skilled workers are required to improve flexibility in production and assignment. Generally the supervisor will assign task to the workers based on skill and skill levels of worker. Since in fashion industry new product styles are launched more frequently and the order size tends to be smaller, the workers always learn when the raw material and the production process changes. Consequently they require less time to produce the succeeding units of a task based on their learning ability. Since the workers have both experience and inexperience workers, so each worker has different skill level and learning ability. Consequently, the assignment which assumed constant skill level is not proper to use. This paper proposes a task-worker assignment considering worker skill levels and learning abilities. Processing time of each worker changes along production period due to a worker learning ability. We focus on a task-worker assignment in a fashion industry where tasks are ordered in series; the number of tasks is greater than the number of workers. Therefore, workers can perform multiple assignments followed the precedence restriction as an assembly line balancing problem. The problem is formulated in an integer linear programming model with objective to minimize makespan. A heuristic is proposed to determine the lower bound (LB and the upper bound (UB of the problem and the best assignment is determined. The performance of the heuristic method is tested by comparing quality of solution and computational time to optimal solutions.
18. Staff assignment practices in nursing homes: review of the literature.
Science.gov (United States)
Rahman, Anna; Straker, Jane K; Manning, Lydia
2009-01-01
Consistent assignment, whereby nursing home staff members, particularly certified nurse aides, are assigned to the same residents on most shifts, is increasingly viewed as a cornerstone of culture change in nursing homes. It has been advocated as a best-care model that increases residents' quality of life while contributing to a more stable frontline staff. Given these potential benefits, consistent assignment is now widely viewed as superior to rotating assignment, an alternative staffing model that aims to distribute care burden more fairly among staff and ensure that workers are familiar with most residents. Despite favorable anecdotal reports about the benefits of consistent assignment, the research literature reports mixed and sometimes contradictory findings for this staffing practice. This article reviews the research pertaining to staff assignment practices in nursing homes. Reviewed here are 13 reports on experimental trials (6 reports), evaluation research (4 reports), and nursing home surveys (3 reports). The review reveals broad diversity in staffing practices and raises questions that challenge popular assumptions about consistent assignment. The article closes with a discussion of the research, policy, and practice implications of the research findings.
19. Assigning breed origin to alleles in crossbred animals.
Science.gov (United States)
Vandenplas, Jérémie; Calus, Mario P L; Sevillano, Claudia A; Windig, Jack J; Bastiaansen, John W M
2016-08-22
For some species, animal production systems are based on the use of crossbreeding to take advantage of the increased performance of crossbred compared to purebred animals. Effects of single nucleotide polymorphisms (SNPs) may differ between purebred and crossbred animals for several reasons: (1) differences in linkage disequilibrium between SNP alleles and a quantitative trait locus; (2) differences in genetic backgrounds (e.g., dominance and epistatic interactions); and (3) differences in environmental conditions, which result in genotype-by-environment interactions. Thus, SNP effects may be breed-specific, which has led to the development of genomic evaluations for crossbred performance that take such effects into account. However, to estimate breed-specific effects, it is necessary to know breed origin of alleles in crossbred animals. Therefore, our aim was to develop an approach for assigning breed origin to alleles of crossbred animals (termed BOA) without information on pedigree and to study its accuracy by considering various factors, including distance between breeds. The BOA approach consists of: (1) phasing genotypes of purebred and crossbred animals; (2) assigning breed origin to phased haplotypes; and (3) assigning breed origin to alleles of crossbred animals based on a library of assigned haplotypes, the breed composition of crossbred animals, and their SNP genotypes. The accuracy of allele assignments was determined for simulated datasets that include crosses between closely-related, distantly-related and unrelated breeds. Across these scenarios, the percentage of alleles of a crossbred animal that were correctly assigned to their breed origin was greater than 90 %, and increased with increasing distance between breeds, while the percentage of incorrectly assigned alleles was always less than 2 %. For the remaining alleles, i.e. 0 to 10 % of all alleles of a crossbred animal, breed origin could not be assigned. The BOA approach accurately assigns
20. Fuzzy topological digital space and digital fuzzy spline of electroencephalography during epileptic seizures
Science.gov (United States)
Shah, Mazlina Muzafar; Wahab, Abdul Fatah
2017-08-01
Epilepsy disease occurs because of there is a temporary electrical disturbance in a group of brain cells (nurons). The recording of electrical signals come from the human brain which can be collected from the scalp of the head is called Electroencephalography (EEG). EEG then considered in digital format and in fuzzy form makes it a fuzzy digital space data form. The purpose of research is to identify the area (curve and surface) in fuzzy digital space affected by inside epilepsy seizure in epileptic patient's brain. The main focus for this research is to generalize fuzzy topological digital space, definition and basic operation also the properties by using digital fuzzy set and the operations. By using fuzzy digital space, the theory of digital fuzzy spline can be introduced to replace grid data that has been use previously to get better result. As a result, the flat of EEG can be fuzzy topological digital space and this type of data can be use to interpolate the digital fuzzy spline.
1. Digital disruption ?syndromes.
Science.gov (United States)
Sullivan, Clair; Staib, Andrew
2017-05-18
The digital transformation of hospitals in Australia is occurring rapidly in order to facilitate innovation and improve efficiency. Rapid transformation can cause temporary disruption of hospital workflows and staff as processes are adapted to the new digital workflows. The aim of this paper is to outline various types of digital disruption and some strategies for effective management. A large tertiary university hospital recently underwent a rapid, successful roll-out of an integrated electronic medical record (EMR). We observed this transformation and propose several digital disruption "syndromes" to assist with understanding and management during digital transformation: digital deceleration, digital transparency, digital hypervigilance, data discordance, digital churn and post-digital 'depression'. These 'syndromes' are defined and discussed in detail. Successful management of this temporary digital disruption is important to ensure a successful transition to a digital platform. What is known about this topic? Digital disruption is defined as the changes facilitated by digital technologies that occur at a pace and magnitude that disrupt established ways of value creation, social interactions, doing business and more generally our thinking. Increasing numbers of Australian hospitals are implementing digital solutions to replace traditional paper-based systems for patient care in order to create opportunities for improved care and efficiencies. Such large scale change has the potential to create transient disruption to workflows and staff. Managing this temporary disruption effectively is an important factor in the successful implementation of an EMR. What does this paper add? A large tertiary university hospital recently underwent a successful rapid roll-out of an integrated electronic medical record (EMR) to become Australia's largest digital hospital over a 3-week period. We observed and assisted with the management of several cultural, behavioural and
2. Ageing and digital games
DEFF Research Database (Denmark)
Iversen, Sara Mosberg
Digital games are still to a great degree considered a medium mainly for young boys. However, available statistics on Western media use show that this is far from the case. Increasingly, people of all ages and genders play digital games, also older adults in their early 60s and beyond. The aim...... of the book is to examine, analyse and discuss: 1) What older adults do with digital games and what meanings the use of digital games take on in the everyday life of older adults; 2) How older adults are perceived by society in relation to digital games; 3) How play and games can be used both...
3. Digital Living at Home
DEFF Research Database (Denmark)
Andersen, Pernille Viktoria Kathja; Christiansen, Ellen Tove
2013-01-01
of these user voices has directed us towards a ‘home-keeping’ design discourse, which opens new horizons for design of digital home control systems by allowing users to perform as self-determined controllers and groomers of their habitat. The paper concludes by outlining the implications of a ‘home......Does living with digital technology inevitably lead to digital living? Users talking about a digital home control system, they have had in their homes for eight years, indicate that there is more to living with digital technology than a functional-operational grip on regulation. Our analysis......-keeping’ design discourse....
4. Digital positron annihilation spectrometer
International Nuclear Information System (INIS)
Cheng Bin; Weng Huimin; Han Rongdian; Ye Bangjiao
2010-01-01
With the high speed development of digital signal process, the technique of the digitization and processing of signals was applied in the domain of a broad class of nuclear technique. The development of digital positron lifetime spectrometer (DPLS) is more promising than the conventional positron lifetime spectrometer equipped with nuclear instrument modules. And digital lifetime spectrometer has many advantages, such as low noise, long term stability, flexible online or offline digital processing, simple setup, low expense, easy to setting, and more physical information. Digital constant fraction discrimination is for timing. And a new method of optimizing energy windows setting for digital positron lifetime spectrometer is also developed employing the simulated annealing for the convenient use. The time resolution is 220ps and the count rate is 200cps. (authors)
5. Calibrated peer review assignments for the earth sciences
Science.gov (United States)
Rudd, J.A.; Wang, V.Z.; Cervato, C.; Ridky, R.W.
2009-01-01
Calibrated Peer Review ??? (CPR), a web-based instructional tool developed as part of the National Science Foundation reform initiatives in undergraduate science education, allows instructors to incorporate multiple writing assignments in large courses without overwhelming the instructor. This study reports successful implementation of CPR in a large, introductory geology course and student learning of geoscience content. For each CPR assignment in this study, students studied web-based and paper resources, wrote an essay, and reviewed seven essays (three from the instructor, three from peers, and their own) on the topic. Although many students expressed negative attitudes and concerns, particularly about the peer review process of this innovative instructional approach, they also recognized the learning potential of completing CPR assignments. Comparing instruction on earthquakes and plate boundaries using a CPR assignment vs. an instructional video lecture and homework essay with extensive instructor feedback, students mastered more content via CPR instruction.
6. Characterizing Sailor and Command Enlisted Placement and Assignment Preferences
National Research Council Canada - National Science Library
Butler, Virginia
2002-01-01
.... DON currently matches sailors to billets using a labor-intensive detailing process. With evolving information technology, the assignment process could be accomplished using intelligent agents and web-based markets...
7. A Qualitative Analysis of the Turkish Gendarmerie Assignment Process
National Research Council Canada - National Science Library
2005-01-01
...; this number increases to 43 million (65% of the population) in the summer months. This study is an organizational analysis of the current assignment process of the Turkish General Command of the Gendarmerie...
8. 46 CFR 42.05-10 - Assigning authority.
Science.gov (United States)
2010-10-01
... Definition of Terms Used in This Subchapter § 42.05-10 Assigning authority. This term means the “American Bureau of Shipping” or such other recognized classification society which the Commandant may approve as...
9. ZAP: a distributed channel assignment algorithm for cognitive radio networks
Directory of Open Access Journals (Sweden)
Munaretto Anelise
2011-01-01
Full Text Available Abstract We propose ZAP, an algorithm for the distributed channel assignment in cognitive radio (CR networks. CRs are capable of identifying underutilized licensed bands of the spectrum, allowing their reuse by secondary users without interfering with primary users. In this context, efficient channel assignment is challenging as ideally it must be simple, incur acceptable communication overhead, provide timely response, and be adaptive to accommodate frequent changes in the network. Another challenge is the optimization of network capacity through interference minimization. In contrast to related work, ZAP addresses these challenges with a fully distributed approach based only on local (neighborhood knowledge, while significantly reducing computational costs and the number of messages required for channel assignment. Simulations confirm the efficiency of ZAP in terms of (i the performance tradeoff between different metrics and (ii the fast achievement of a suitable assignment solution regardless of network size and density.
10. Dynamic Passenger Assignment during Disruptions in Railway Systems
NARCIS (Netherlands)
Zhu, Y.; Goverde, R.M.P.
2017-01-01
Passenger-oriented rescheduling problems receive increasing attention. However, the passenger assignment models used for evaluating the rescheduling solutions are usually simplified by many assumptions. To estimate passenger inconvenience more accurately, this paper establishes a dynamic passenger
11. A singular value sensitivity approach to robust eigenstructure assignment
DEFF Research Database (Denmark)
Søgaard-Andersen, Per; Trostmann, Erik; Conrad, Finn
1986-01-01
A design technique for improving the feedback properties of multivariable state feedback systems designed using eigenstructure assignment is presented. Based on a singular value analysis of the feedback properties a design parameter adjustment procedure is outlined. This procedure allows...
12. Subcarrier Group Assignment for MC-CDMA Wireless Networks
Directory of Open Access Journals (Sweden)
Le-Ngoc Tho
2007-01-01
Full Text Available Two interference-based subcarrier group assignment strategies in dynamic resource allocation are proposed for MC-CDMA wireless systems to achieve high throughput in a multicell environment. Least interfered group assignment (LIGA selects for each session the subcarrier group on which the user receives the minimum interference, while best channel ratio group assignment (BCRGA chooses the subcarrier group with the largest channel response-to-interference ratio. Both analytical framework and simulation model are developed for evaluation of throughput distribution of the proposed schemes. An iterative approach is devised to handle the complex interdependency between multicell interference profiles in the throughput analysis. Illustrative results show significant throughput improvement offered by the interference-based assignment schemes for MC-CDMA multicell wireless systems. In particular, under low loading conditions, LIGA renders the best performance. However, as the load increases BCRGA tends to offer superior performance.
13. Subcarrier Group Assignment for MC-CDMA Wireless Networks
Directory of Open Access Journals (Sweden)
Tho Le-Ngoc
2007-12-01
Full Text Available Two interference-based subcarrier group assignment strategies in dynamic resource allocation are proposed for MC-CDMA wireless systems to achieve high throughput in a multicell environment. Least interfered group assignment (LIGA selects for each session the subcarrier group on which the user receives the minimum interference, while best channel ratio group assignment (BCRGA chooses the subcarrier group with the largest channel response-to-interference ratio. Both analytical framework and simulation model are developed for evaluation of throughput distribution of the proposed schemes. An iterative approach is devised to handle the complex interdependency between multicell interference profiles in the throughput analysis. Illustrative results show significant throughput improvement offered by the interference-based assignment schemes for MC-CDMA multicell wireless systems. In particular, under low loading conditions, LIGA renders the best performance. However, as the load increases BCRGA tends to offer superior performance.
14. Digital Banking: Risks of Financial Digitalization
Directory of Open Access Journals (Sweden)
Kornіvska Valerіa O.
2017-09-01
Full Text Available The paper demonstrates the results of the research into development of the digital economy in the global financial space, shows the contradictions of these processes in the context of the growth of financial inclusion of households, identifies the risks of active introduction of digital banking in poor countries of the world. The characteristics of the processes of growth of the influence of banking institutions on the operational activity and daily life of households are given, and it is proved that under conditions of digital banking, without having any other alternative ways of economic activity in terms of money circulation than non-cash turnover, clients are forced to agree to unlimited presence of financial operators in social systems. It is substantiated that in Ukraine the global risk of digitalization of the society is gradually developing as a result of the creation of unified information systems for the control of global financial flows.
15. Digital rights management for digital cinema
Science.gov (United States)
Kirovski, Darko; Peinado, Marcus; Petitcolas, Fabien A. P.
2001-12-01
There is a wide consensus among the feature film production studios that the Internet era brings a new paradigm for film distribution to cinemas worldwide. The benefits of digital cinema to both producers and cinemas are numerous: significantly lower distribution and maintenance costs, immediate access to film libraries, higher presentation quality, and strong potential for developing new business models. Despite these advantages, the studios are still reluctant to jump into the digital age. The main showstopper for digital cinema is the danger of widespread piracy. Piracy already costs Hollywood an estimated two billion dollars annually and digital cinema without proper copyright enforcement could increase this number. In this paper, we present a copyright management system that aims at providing the set of necessary security tools: standard cryptographic primitives and copyright protection mechanisms that enable a reliable and secure feature film delivery system.
16. ZAP: a distributed channel assignment algorithm for cognitive radio networks
OpenAIRE
Junior , Paulo Roberto ,; Fonseca , Mauro; Munaretto , Anelise; Viana , Aline ,; Ziviani , Artur
2011-01-01
Abstract We propose ZAP, an algorithm for the distributed channel assignment in cognitive radio (CR) networks. CRs are capable of identifying underutilized licensed bands of the spectrum, allowing their reuse by secondary users without interfering with primary users. In this context, efficient channel assignment is challenging as ideally it must be simple, incur acceptable communication overhead, provide timely response, and be adaptive to accommodate frequent changes in the network. Another ...
17. A parametric visualization software for the assignment problem
Directory of Open Access Journals (Sweden)
Papamanthou Charalampos
2005-01-01
Full Text Available In this paper we present a parametric visualization software used to assist the teaching of the Network Primal Simplex Algorithm for the assignment problem (AP. The assignment problem is a special case of the balanced transportation problem. The main functions of the algorithm and design techniques are also presented. Through this process, we aim to underline the importance and necessity of using such educational methods in order to improve the teaching of Computer Algorithms.
18. A demand assignment control in international business satellite communications network
Science.gov (United States)
Nohara, Mitsuo; Takeuchi, Yoshio; Takahata, Fumio; Hirata, Yasuo
An experimental system is being developed for use in an international business satellite (IBS) communications network based on demand-assignment (DA) and TDMA techniques. This paper discusses its system design, in particular from the viewpoints of a network configuration, a DA control, and a satellite channel-assignment algorithm. A satellite channel configuration is also presented along with a tradeoff study on transmission rate, HPA output power, satellite resource efficiency, service quality, and so on.
19. Digital Collections, Digital Libraries and the Digitization of Cultural Heritage Information.
Science.gov (United States)
Lynch, Clifford
2002-01-01
Discusses the development of digital collections and digital libraries. Topics include digitization of cultural heritage information; broadband issues; lack of compelling content; training issues; types of materials being digitized; sustainability; digital preservation; infrastructure; digital images; data mining; and future possibilities for…
20. Interactive visual exploration and refinement of cluster assignments.
Science.gov (United States)
Kern, Michael; Lex, Alexander; Gehlenborg, Nils; Johnson, Chris R
2017-09-12
With ever-increasing amounts of data produced in biology research, scientists are in need of efficient data analysis methods. Cluster analysis, combined with visualization of the results, is one such method that can be used to make sense of large data volumes. At the same time, cluster analysis is known to be imperfect and depends on the choice of algorithms, parameters, and distance measures. Most clustering algorithms don't properly account for ambiguity in the source data, as records are often assigned to discrete clusters, even if an assignment is unclear. While there are metrics and visualization techniques that allow analysts to compare clusterings or to judge cluster quality, there is no comprehensive method that allows analysts to evaluate, compare, and refine cluster assignments based on the source data, derived scores, and contextual data. In this paper, we introduce a method that explicitly visualizes the quality of cluster assignments, allows comparisons of clustering results and enables analysts to manually curate and refine cluster assignments. Our methods are applicable to matrix data clustered with partitional, hierarchical, and fuzzy clustering algorithms. Furthermore, we enable analysts to explore clustering results in context of other data, for example, to observe whether a clustering of genomic data results in a meaningful differentiation in phenotypes. Our methods are integrated into Caleydo StratomeX, a popular, web-based, disease subtype analysis tool. We show in a usage scenario that our approach can reveal ambiguities in cluster assignments and produce improved clusterings that better differentiate genotypes and phenotypes.
1. PARETO OPTIMAL SOLUTIONS FOR MULTI-OBJECTIVE GENERALIZED ASSIGNMENT PROBLEM
Directory of Open Access Journals (Sweden)
S. Prakash
2012-01-01
Full Text Available
ENGLISH ABSTRACT: The Multi-Objective Generalized Assignment Problem (MGAP with two objectives, where one objective is linear and the other one is non-linear, has been considered, with the constraints that a job is assigned to only one worker – though he may be assigned more than one job, depending upon the time available to him. An algorithm is proposed to find the set of Pareto optimal solutions of the problem, determining assignments of jobs to workers with two objectives without setting priorities for them. The two objectives are to minimise the total cost of the assignment and to reduce the time taken to complete all the jobs.
AFRIKAANSE OPSOMMING: ‘n Multi-doelwit veralgemeende toekenningsprobleem (“multi-objective generalised assignment problem – MGAP” met twee doelwitte, waar die een lineêr en die ander nielineêr is nie, word bestudeer, met die randvoorwaarde dat ‘n taak slegs toegedeel word aan een werker – alhoewel meer as een taak aan hom toegedeel kan word sou die tyd beskikbaar wees. ‘n Algoritme word voorgestel om die stel Pareto-optimale oplossings te vind wat die taaktoedelings aan werkers onderhewig aan die twee doelwitte doen sonder dat prioriteite toegeken word. Die twee doelwitte is om die totale koste van die opdrag te minimiseer en om die tyd te verminder om al die take te voltooi.
2. Phonological loop affects children's interpretations of explicit but not ambiguous questions: Research on links between working memory and referent assignment.
Science.gov (United States)
Meng, Xianwei; Murakami, Taro; Hashiya, Kazuhide
2017-01-01
Understanding the referent of other's utterance by referring the contextual information helps in smooth communication. Although this pragmatic referential process can be observed even in infants, its underlying mechanism and relative abilities remain unclear. This study aimed to comprehend the background of the referential process by investigating whether the phonological loop affected the referent assignment. A total of 76 children (43 girls) aged 3-5 years participated in a reference assignment task in which an experimenter asked them to answer explicit (e.g., "What color is this?") and ambiguous (e.g., "What about this?") questions about colorful objects. The phonological loop capacity was measured by using the forward digit span task in which children were required to repeat the numbers as an experimenter uttered them. The results showed that the scores of the forward digit span task positively predicted correct response to explicit questions and part of the ambiguous questions. That is, the phonological loop capacity did not have effects on referent assignment in response to ambiguous questions that were asked after a topic shift of the explicit questions and thus required a backward reference to the preceding explicit questions to detect the intent of the current ambiguous questions. These results suggest that although the phonological loop capacity could overtly enhance the storage of verbal information, it does not seem to directly contribute to the pragmatic referential process, which might require further social cognitive processes.
3. Phonological loop affects children's interpretations of explicit but not ambiguous questions: Research on links between working memory and referent assignment.
Directory of Open Access Journals (Sweden)
Xianwei Meng
Full Text Available Understanding the referent of other's utterance by referring the contextual information helps in smooth communication. Although this pragmatic referential process can be observed even in infants, its underlying mechanism and relative abilities remain unclear. This study aimed to comprehend the background of the referential process by investigating whether the phonological loop affected the referent assignment. A total of 76 children (43 girls aged 3-5 years participated in a reference assignment task in which an experimenter asked them to answer explicit (e.g., "What color is this?" and ambiguous (e.g., "What about this?" questions about colorful objects. The phonological loop capacity was measured by using the forward digit span task in which children were required to repeat the numbers as an experimenter uttered them. The results showed that the scores of the forward digit span task positively predicted correct response to explicit questions and part of the ambiguous questions. That is, the phonological loop capacity did not have effects on referent assignment in response to ambiguous questions that were asked after a topic shift of the explicit questions and thus required a backward reference to the preceding explicit questions to detect the intent of the current ambiguous questions. These results suggest that although the phonological loop capacity could overtly enhance the storage of verbal information, it does not seem to directly contribute to the pragmatic referential process, which might require further social cognitive processes.
4. Effect on injuries of assigning shoes based on foot shape in air force basic training.
Science.gov (United States)
Knapik, Joseph J; Brosch, Lorie C; Venuto, Margaret; Swedler, David I; Bullock, Steven H; Gaines, Lorraine S; Murphy, Ryan J; Tchandja, Juste; Jones, Bruce H
2010-01-01
This study examined whether assigning running shoes based on the shape of the bottom of the foot (plantar surface) influenced injury risk in Air Force Basic Military Training (BMT) and examined risk factors for injury in BMT. Data were collected from BMT recruits during 2007; analysis took place during 2008. After foot examinations, recruits were randomly consigned to either an experimental group (E, n=1042 men, 375 women) or a control group (C, n=913 men, 346 women). Experimental group recruits were assigned motion control, stability, or cushioned shoes for plantar shapes indicative of low, medium, or high arches, respectively. Control group recruits received a stability shoe regardless of plantar shape. Injuries during BMT were determined from outpatient visits provided from the Defense Medical Surveillance System. Other injury risk factors (fitness, smoking, physical activity, prior injury, menstrual history, and demographics) were obtained from a questionnaire, existing databases, or BMT units. Multivariate Cox regression controlling for other risk factors showed little difference in injury risk between the groups among men (hazard ratio [E/C]=1.11, 95% CI=0.89-1.38) or women (hazard ratio [E/C]=1.20, 95% CI= 0.90-1.60). Independent injury risk factors among both men and women included low aerobic fitness and cigarette smoking. This prospective study demonstrated that assigning running shoes based on the shape of the plantar surface had little influence on injury risk in BMT even after controlling for other injury risk factors. Published by Elsevier Inc.
5. Digital Simulation in the Geosciences
Directory of Open Access Journals (Sweden)
Alexandr A. Lobanov
2014-09-01
Full Text Available This article provides an analysis of methods for digital modeling in the area of Earth Sciences. The author illustrates the difference between digital modeling in radio communication and that in the area of Earth Sciences. The article examines the integration aspect of digital models, demonstrates the advantages of digital over analog models, and illustrates that digital models are discrete. The author outlines the characteristics of digital modeling and illustrates the logical structure of digital models.
International Nuclear Information System (INIS)
Todd-Pokropek, A.
1991-01-01
With the access to digital methods for handling and processing images in general, many medical imaging methods are becoming more effectively handled digitally. This applies in particular to basically digital techniques such as CT and MR but also now includes Nuclear Medicine (NM), Ultrasound (US) and a variety of radiological procedures such as Digital Subtraction Angiography (DSA) and Fluoroscopy (DF). The access to conventional projection images by stimulatable plates (CR) or by digitization of film makes all of radiology potentially accessible, and the management of such images by a network is the basic aim of Picture Archiving and Communication Systems (PACS). However, it is suggested that in order for such systems to be of greater value, that way in which such images are treated needs to change, that is, digital images can be used to derive additional clinical value by appropriate processing
7. Digital cine-imaging
International Nuclear Information System (INIS)
Masuda, Kazuhiro
1992-01-01
Digitization of fluoroscopic images has been developed for the digital cine imaging system as a result of the computer technology, television technology, and popularization of interventional radiology. Present digital cine imaging system is able to offer images similar to cine film because of the higher operatability and better image quality with the development of interventional radiology. As a result, its higher usefulness for catheter diagnosis examination except for interventional radiology was reported, and the possibility of having filmless cine is close to becoming a reality. However several problems have been pointed out, such as spatial resolution, time resolution, storage and exchangeability of data, disconsolidated viewing functions, etc. Anyhow, digital cine imaging system has some unresolved points and lots the needs to be discussed. The tendency of digitization is the passage of the time and we have to promote a study for more useful digital cine imaging system in team medical treatment which centers on the patients. (author)
8. Theory of Digital Automata
CERN Document Server
Borowik, Bohdan; Lahno, Valery; Petrov, Oleksandr
2013-01-01
This book serves a dual purpose: firstly to combine the treatment of circuits and digital electronics, and secondly, to establish a strong connection with the contemporary world of digital systems. The need for this approach arises from the observation that introducing digital electronics through a course in traditional circuit analysis is fast becoming obsolete. Our world has gone digital. Automata theory helps with the design of digital circuits such as parts of computers, telephone systems and control systems. A complete perspective is emphasized, because even the most elegant computer architecture will not function without adequate supporting circuits. The focus is on explaining the real-world implementation of complete digital systems. In doing so, the reader is prepared to immediately begin design and implementation work. This work serves as a bridge to take readers from the theoretical world to the everyday design world where solutions must be complete to be successful.
9. Digital collections and exhibits
CERN Document Server
Denzer, Juan
2015-01-01
Today's libraries are taking advantage of cutting-edge technologies such as flat panel displays using touch, sound, and hands-free motions to design amazing exhibits using everything from simple computer hardware to advanced technologies such as the Microsoft Kinect. Libraries of all types are striving to add new interactive experiences for their patrons through exciting digital exhibits, both online and off. Digital Collections and Exhibits takes away the mystery of designing stunning digital exhibits to spotlight library trea
10. The digital computer
CERN Document Server
Parton, K C
2014-01-01
The Digital Computer focuses on the principles, methodologies, and applications of the digital computer. The publication takes a look at the basic concepts involved in using a digital computer, simple autocode examples, and examples of working advanced design programs. Discussions focus on transformer design synthesis program, machine design analysis program, solution of standard quadratic equations, harmonic analysis, elementary wage calculation, and scientific calculations. The manuscript then examines commercial and automatic programming, how computers work, and the components of a computer
11. Digital Textile Printing
OpenAIRE
Moltchanova, Julia
2011-01-01
Rapidly evolving technology of digital printing opens new opportunities on many markets. One of them is the printed fabric market where printing companies as well as clients benefit from new printing methods. This thesis focuses on the digital textile printing technology and its implementation for fabric-on-demand printing service in Finland. The purpose of this project was to study the technology behind digital textile printing, areas of application of this technology, the requirements ...
12. Digital Sensor Technology
Energy Technology Data Exchange (ETDEWEB)
Thomas, Ken D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Quinn, Edward L. [Technology Resources, Dana Point, CA (United States); Mauck, Jerry L. [Technology Resources, Dana Point, CA (United States); Bockhorst, Richard M. [Technology Resources, Dana Point, CA (United States)
2015-02-01
The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy and reliability. This paper, which refers to a final report issued in 2013, demonstrates these benefits in direct comparisons of digital and analog sensor applications. Improved accuracy results from the superior operating characteristics of digital sensors. These include improvements in sensor accuracy and drift and other related parameters which reduce total loop uncertainty and thereby increase safety and operating margins. An example instrument loop uncertainty calculation for a pressure sensor application is presented to illustrate these improvements. This is a side-by-side comparison of the instrument loop uncertainty for both an analog and a digital sensor in the same pressure measurement application. Similarly, improved sensor reliability is illustrated with a sample calculation for determining the probability of failure on demand, an industry standard reliability measure. This looks at equivalent analog and digital temperature sensors to draw the comparison. The results confirm substantial reliability improvement with the digital sensor, due in large part to ability to continuously monitor the health of a digital sensor such that problems can be immediately identified and corrected. This greatly reduces the likelihood of a latent failure condition of the sensor at the time of a design basis event. Notwithstanding the benefits of digital sensors, there are certain qualification issues that are inherent with digital technology and these are described in the report. One major qualification impediment for digital sensor implementation is software common cause failure (SCCF).
13. Preserving Digital Materials
CERN Document Server
Harvey, Ross
2011-01-01
This book provides a single-volume introduction to the principles, strategies and practices currently applied by librarians and recordkeeping professionals to the critical issue of preservation of digital information. It incorporates practice from both the recordkeeping and the library communities, taking stock of current knowledge about digital preservation and describing recent and current research, to provide a framework for reflecting on the issues that digital preservation raises in professional practice.
14. Dakwah di Era Digital
OpenAIRE
Budiantoro, Wahyu
2018-01-01
These days dakwah is not only interpreted as transformation of a pure religious value, but also transformation of a more relevant value including many aspects in digital era. Digital era is when society succumbed into the flow of information causing cultural shock and difficulties on synthesizing meaning from those scattered information. Dakwah on Digital age must accommodate societal needs which tend to move into a mass society. It results in strategy and more humane and innovative dakwah me...
15. The Digital Imperative
OpenAIRE
Veling, Louise; Murnane, Sinéad; Carcary, Marian; Zlydareva, Olga
2014-01-01
The pervasiveness of digital technologies and their potential for reshaping the industry landscape dictates that organizations operating today have little choice but to incorporate digital technologies into their business strategies. Failure to do so will impede the business’s viability, and may ultimately lead to business failure. However, for those organizations that successfully transition to digital business, unprecedented business opportunities exist for value creation and reali...
16. Digital piracy : theory
OpenAIRE
BELLEFLAMME, Paul; PEITZ, Martin
2010-01-01
This article reviews recent theoretical contributions on digital piracy. It starts by elaborating on the reasons for intellectual property protection, by reporting a few facts about copyright protection, and by examining reasons to become a digital pirate. Next, it provides an exploration of the consequences of digital piracy, using a base model and several extensions (with consumer sampling, network effects, and indirect appropriation). A closer look at market-structure implications of end-u...
Directory of Open Access Journals (Sweden)
Carlos Eduardo Cortés S.
2015-01-01
Full Text Available La radio digital es un producto de la llamada convergencia digital. Las nuevas tecnologías interconectadas permiten la aparición de nuevos modos de audiencia y la implementación de herramientas versátiles. Habla del problema de los estándares, de la radio satelital, la radio digital terrestre, las radios internacionales, la interactividad.
18. Easy digital engineering
International Nuclear Information System (INIS)
Jin, Dal Bok
2002-02-01
This book lists basic of digital engineering, number system and digital code, Boolean algebra and basic logic circuit, simplify of logical expression, combinational circuit, arithmetic circuit, multivibrator circuit, sequential circuit, memory unit of semiconductor and logical element for program, D/A converter and A/D converter, logic element and integrated circuit and logic circuit and micro controller. It has exercises and answers about digital engineering and summary in the end of each chapter.
19. Debunking the "Digital Native": Beyond Digital Apartheid, towards Digital Democracy
Science.gov (United States)
Brown, C.; Czerniewicz, L.
2010-01-01
This paper interrogates the currently pervasive discourse of the "net generation" finding the concept of the "digital native" especially problematic, both empirically and conceptually. We draw on a research project of South African higher education students' access to and use of Information and Communication Technologies (ICTs)…
20. Digital Natives and Digital Divide: Analysing Perspective for Emerging Pedagogy
Science.gov (United States)
Onye, Uriel U.; Du, Yunfei
2016-01-01
This paper addresses the concepts of digital natives and digital divide from the perspective of the digital outsiders (part of digital natives). It takes a critical look at the implications of available ICT in both developed and underdeveloped countries in the fight against digital divide. The major contribution to literature is by drawing…
1. Successful replantation in ten-digit amputation.
Science.gov (United States)
Kantarci, Umit; Cepel, Selim; Buldu, Halil
2010-01-01
Amputations involving ten digits are very rare because of different lengths of the digits. A 34-year-old man working in a printing house presented one hour after guillotine amputation involving all ten digits. Surgery was initiated 80 minutes after admission and took seven hours. Under axillary anesthesia, the operation was performed by two teams each consisting of two microsurgeons and two assistants. Replantation was completed without the use of any skin graft or flap. Fingertip examination showed poor arterial circulation in the second, third, and fourth digits of the left hand after 24 hours of replantation and surgical exploration was performed, during which anastomosis of the ulnar digital artery of the second digit was re-established and a Y-shaped vein graft was placed at the level of the third web to restore revascularization of the third and fourth digits. However, these interventions did not prevent the development of necrosis in the distal segment of the fourth digit which resulted in dry gangrene that required amputation. After 38 months of replantation, radiographic examination showed complete union in all fingers without malunion or damage to the joint surface and about 8 degrees of medial angulation in the proximal phalanx of the fourth digit of the right hand. The patient did not have difficulty in performing daily activities and had a considerably good pinching. Losses of active range of motion of the metacarpophalangeal and interphalangeal joints were within the rage of 10 to 30 degrees in both hands. In the assessment of sensation, static and dynamic two-point discrimination test results were 6.1 mm and 4.0 mm, respectively.
2. Socially-assigned race, healthcare discrimination and preventive healthcare services.
Directory of Open Access Journals (Sweden)
Tracy Macintosh
Full Text Available Race and ethnicity, typically defined as how individuals self-identify, are complex social constructs. Self-identified racial/ethnic minorities are less likely to receive preventive care and more likely to report healthcare discrimination than self-identified non-Hispanic whites. However, beyond self-identification, these outcomes may vary depending on whether racial/ethnic minorities are perceived by others as being minority or white; this perception is referred to as socially-assigned race.To examine the associations between socially-assigned race and healthcare discrimination and receipt of selected preventive services.Cross-sectional analysis of the 2004 Behavioral Risk Factor Surveillance System "Reactions to Race" module. Respondents from seven states and the District of Columbia were categorized into 3 groups, defined by a composite of self-identified race/socially-assigned race: Minority/Minority (M/M, n = 6,837, Minority/White (M/W, n = 929, and White/White (W/W, n = 25,913. Respondents were 18 years or older, with 61.7% under age 60; 51.8% of respondents were female. Measures included reported healthcare discrimination and receipt of vaccinations and cancer screenings.Racial/ethnic minorities who reported being socially-assigned as minority (M/M were more likely to report healthcare discrimination compared with those who reported being socially-assigned as white (M/W (8.9% vs. 5.0%, p = 0.002. Those reporting being socially-assigned as white (M/W and W/W had similar rates for past-year influenza (73.1% vs. 74.3% and pneumococcal (69.3% vs. 58.6% vaccinations; however, rates were significantly lower among M/M respondents (56.2% and 47.6%, respectively, p-values<0.05. There were no significant differences between the M/M and M/W groups in the receipt of cancer screenings.Racial/ethnic minorities who reported being socially-assigned as white are more likely to receive preventive vaccinations and less likely to report
3. RNA-PAIRS: RNA probabilistic assignment of imino resonance shifts
International Nuclear Information System (INIS)
Bahrami, Arash; Clos, Lawrence J.; Markley, John L.; Butcher, Samuel E.; Eghbalnia, Hamid R.
2012-01-01
The significant biological role of RNA has further highlighted the need for improving the accuracy, efficiency and the reach of methods for investigating RNA structure and function. Nuclear magnetic resonance (NMR) spectroscopy is vital to furthering the goals of RNA structural biology because of its distinctive capabilities. However, the dispersion pattern in the NMR spectra of RNA makes automated resonance assignment, a key step in NMR investigation of biomolecules, remarkably challenging. Herein we present RNA Probabilistic Assignment of Imino Resonance Shifts (RNA-PAIRS), a method for the automated assignment of RNA imino resonances with synchronized verification and correction of predicted secondary structure. RNA-PAIRS represents an advance in modeling the assignment paradigm because it seeds the probabilistic network for assignment with experimental NMR data, and predicted RNA secondary structure, simultaneously and from the start. Subsequently, RNA-PAIRS sets in motion a dynamic network that reverberates between predictions and experimental evidence in order to reconcile and rectify resonance assignments and secondary structure information. The procedure is halted when assignments and base-parings are deemed to be most consistent with observed crosspeaks. The current implementation of RNA-PAIRS uses an initial peak list derived from proton-nitrogen heteronuclear multiple quantum correlation ( 1 H– 15 N 2D HMQC) and proton–proton nuclear Overhauser enhancement spectroscopy ( 1 H– 1 H 2D NOESY) experiments. We have evaluated the performance of RNA-PAIRS by using it to analyze NMR datasets from 26 previously studied RNAs, including a 111-nucleotide complex. For moderately sized RNA molecules, and over a range of comparatively complex structural motifs, the average assignment accuracy exceeds 90%, while the average base pair prediction accuracy exceeded 93%. RNA-PAIRS yielded accurate assignments and base pairings consistent with imino resonances for a
4. RNA-PAIRS: RNA probabilistic assignment of imino resonance shifts
Energy Technology Data Exchange (ETDEWEB)
Bahrami, Arash; Clos, Lawrence J.; Markley, John L.; Butcher, Samuel E. [National Magnetic Resonance Facility at Madison (United States); Eghbalnia, Hamid R., E-mail: [email protected] [University of Cincinnati, Department of Molecular and Cellular Physiology (United States)
2012-04-15
The significant biological role of RNA has further highlighted the need for improving the accuracy, efficiency and the reach of methods for investigating RNA structure and function. Nuclear magnetic resonance (NMR) spectroscopy is vital to furthering the goals of RNA structural biology because of its distinctive capabilities. However, the dispersion pattern in the NMR spectra of RNA makes automated resonance assignment, a key step in NMR investigation of biomolecules, remarkably challenging. Herein we present RNA Probabilistic Assignment of Imino Resonance Shifts (RNA-PAIRS), a method for the automated assignment of RNA imino resonances with synchronized verification and correction of predicted secondary structure. RNA-PAIRS represents an advance in modeling the assignment paradigm because it seeds the probabilistic network for assignment with experimental NMR data, and predicted RNA secondary structure, simultaneously and from the start. Subsequently, RNA-PAIRS sets in motion a dynamic network that reverberates between predictions and experimental evidence in order to reconcile and rectify resonance assignments and secondary structure information. The procedure is halted when assignments and base-parings are deemed to be most consistent with observed crosspeaks. The current implementation of RNA-PAIRS uses an initial peak list derived from proton-nitrogen heteronuclear multiple quantum correlation ({sup 1}H-{sup 15}N 2D HMQC) and proton-proton nuclear Overhauser enhancement spectroscopy ({sup 1}H-{sup 1}H 2D NOESY) experiments. We have evaluated the performance of RNA-PAIRS by using it to analyze NMR datasets from 26 previously studied RNAs, including a 111-nucleotide complex. For moderately sized RNA molecules, and over a range of comparatively complex structural motifs, the average assignment accuracy exceeds 90%, while the average base pair prediction accuracy exceeded 93%. RNA-PAIRS yielded accurate assignments and base pairings consistent with imino
5. The digital media handbook
CERN Document Server
Dewdney, Andrew
2013-01-01
The new edition of The Digital Media Handbook presents an essential guide to the historical and theoretical development of digital media, emphasising cultural continuity alongside technological change, and highlighting the emergence of new forms of communication in contemporary networked culture.Andrew Dewdney and Peter Ride present detailed critical commentary and descriptive historical accounts, as well as a series of interviews from a range of digital media practitioners, including producers, developers, curators and artists.The Digital Media Handbook highlights key concerns of today's prac
International Nuclear Information System (INIS)
Wenz, W.; Buitrago-Tellez, C.; Blum, U.; Hauenstein, K.H.; Gufler, H.; Meyer, E.; Ruediger, K.
1992-01-01
The diagnostic value of a digitization system for analogue films based on a charge-coupled-device (CCD) scanner with adjustable resolution of 2.5 or 5 lp/mm was assessed. Some 110 skeletal radiographs, 50 contrast studies, including 25 of patients with Crohn's disease, and 70 abdominal plain films before and after successful lithotripsy for renal stones were digitized. Receiver operating characteristic (ROC) studies showed improved detection of cortical and trabecular defects with contrast-optimized digitized films. Edge enhancement algorithms yielded no additional information. Inflammatory lesions of Crohn's disease were detected equally well by conventional films and digitized images. A statistically significant improvement (p [de
7. Digital security technology simplified.
Science.gov (United States)
Scaglione, Bernard J
2007-01-01
Digital security technology is making great strides in replacing analog and other traditional security systems including CCTV card access, personal identification and alarm monitoring applications. Like any new technology, the author says, it is important to understand its benefits and limitations before purchasing and installing, to ensure its proper operation and effectiveness. This article is a primer for security directors on how digital technology works. It provides an understanding of the key components which make up the foundation for digital security systems, focusing on three key aspects of the digital security world: the security network, IP cameras and IP recorders.
8. Digitally-Driven Architecture
Directory of Open Access Journals (Sweden)
Henriette Bier
2014-07-01
Full Text Available The shift from mechanical to digital forces architects to reposition themselves: Architects generate digital information, which can be used not only in designing and fabricating building components but also in embedding behaviours into buildings. This implies that, similar to the way that industrial design and fabrication with its concepts of standardisation and serial production influenced modernist architecture, digital design and fabrication influences contemporary architecture. While standardisation focused on processes of rationalisation of form, mass-customisation as a new paradigm that replaces mass-production, addresses non-standard, complex, and flexible designs. Furthermore, knowledge about the designed object can be encoded in digital data pertaining not just to the geometry of a design but also to its physical or other behaviours within an environment. Digitally-driven architecture implies, therefore, not only digitally-designed and fabricated architecture, it also implies architecture – built form – that can be controlled, actuated, and animated by digital means.In this context, this sixth Footprint issue examines the influence of digital means as pragmatic and conceptual instruments for actuating architecture. The focus is not so much on computer-based systems for the development of architectural designs, but on architecture incorporating digital control, sensing, actuating, or other mechanisms that enable buildings to interact with their users and surroundings in real time in the real world through physical or sensory change and variation.
9. Digitally-Driven Architecture
Directory of Open Access Journals (Sweden)
Henriette Bier
2010-06-01
Full Text Available The shift from mechanical to digital forces architects to reposition themselves: Architects generate digital information, which can be used not only in designing and fabricating building components but also in embedding behaviours into buildings. This implies that, similar to the way that industrial design and fabrication with its concepts of standardisation and serial production influenced modernist architecture, digital design and fabrication influences contemporary architecture. While standardisation focused on processes of rationalisation of form, mass-customisation as a new paradigm that replaces mass-production, addresses non-standard, complex, and flexible designs. Furthermore, knowledge about the designed object can be encoded in digital data pertaining not just to the geometry of a design but also to its physical or other behaviours within an environment. Digitally-driven architecture implies, therefore, not only digitally-designed and fabricated architecture, it also implies architecture – built form – that can be controlled, actuated, and animated by digital means. In this context, this sixth Footprint issue examines the influence of digital means as pragmatic and conceptual instruments for actuating architecture. The focus is not so much on computer-based systems for the development of architectural designs, but on architecture incorporating digital control, sensing, actuating, or other mechanisms that enable buildings to interact with their users and surroundings in real time in the real world through physical or sensory change and variation.
10. Exploring digital professionalism.
Science.gov (United States)
Ellaway, Rachel H; Coral, Janet; Topps, David; Topps, Maureen
2015-01-01
The widespread use of digital media (both computing devices and the services they access) has blurred the boundaries between our personal and professional lives. Contemporary students are the last to remember a time before the widespread use of the Internet and they will be the first to practice in a largely e-health environment. This article explores concepts of digital professionalism and their place in contemporary medical education, and proposes a series of principles of digital professionalism to guide teaching, learning and practice in the healthcare professions. Despite the many risks and fears surrounding their use, digital media are not an intrinsic threat to medical professionalism. Professionals should maintain the capacity for deliberate, ethical, and accountable practice when using digital media. The authors describe a digital professionalism framework structured around concepts of proficiency, reputation, and responsibility. Digital professionalism can be integrated into medical education using strategies based on awareness, alignment, assessment, and accountability. These principles of digital professionalism provide a way for medical students and medical practitioners to embrace the positive aspects of digital media use while being mindful and deliberate in its use to avoid or minimize any negative consequences.
International Nuclear Information System (INIS)
McFee, W.H.
1988-01-01
Until recently, all film digitizing devices for use with teleradiology or picture archiving and communication systems used a video camera to capture an image of the radiograph for subsequent digitization. The development of film digitizers that use a laser beam to scan the film represents a significant advancement in digital technology, resulting in improved image quality compared with video scanners. This paper discusses differences in resolution, efficiency, reliability, and the cost between these two types of devices. The results of a modified receiver operating characteristic comparison study of a video scanner and a laser scanner manufactured by the same company are also discussed
12. Triage level assignment and nurse characteristics and experience.
Science.gov (United States)
Gómez-Angelats, Elisenda; Miró, Òscar; Bragulat Baur, Ernesto; Antolín Santaliestra, Alberto; Sánchez Sánchez, Miquel
2018-06-01
To study the relation between nursing staff demographics and experience and their assignment of triage level in the emergency department. One-year retrospective observational study in the triage area of a tertiary care urban university hospital that applies the Andorran-Spanish triage model. Variables studied were age, gender, nursing experience, triage experience, shift, usual level of emergency work the nurse undertakes, number of triage decisions made, and percentage of patients assigned to each level. Fifty nurses (5 men, 45 women) with a mean (SD) age of 45 (9) years triaged 67 803 patients during the year. Nurses classified more patients in level 5 on the morning shift (7.9%) than on the afternoon shift (5.5%) (P=.003). The difference in the rate of level-5 triage classification became significant when nurses were older (β = 0.092, P=.037) and experience was greater (β = 0.103, P=.017). The number of triages recorded by a nurse was significantly and directly related to the percentage of patients assigned to level 3 (β = 0.003, P=.006) and inversely related to the percentages assigned to level 4 (β = -0.002, P=.008) and level 5 (β = -0.001, P=.017). We found that triage level assignments were related to age, experience, shift, and total number of patients triaged by a nurse.
13. Assigning spectra of chaotic molecules with diabatic correlation diagrams
International Nuclear Information System (INIS)
Rose, J.P.; Kellman, M.E.
1996-01-01
An approach for classifying and organizing spectra of highly excited vibrational states of molecules is investigated. As a specific example, we analyze the spectrum of an effective spectroscopic fitting Hamiltonian for H 2 O. In highly excited spectra, multiple resonance couplings and anharmonicity interact to give branching of the N original normal modes into new anharmonic modes, accompanied by the onset of widespread chaos. The anharmonic modes are identified by means of a bifurcation analysis of the spectroscopic Hamiltonian. A diabatic correlation diagram technique is developed to assign the levels with approximate open-quote open-quote dynamical close-quote close-quote quantum numbers corresponding to the dynamics determined from the bifurcation analysis. The resulting assignment shows significant disturbance from the conventional spectral pattern organization into sequences and progressions. The open-quote open-quote dynamical close-quote close-quote assignment is then converted into an assignment in terms of open-quote open-quote nominal close-quote close-quote quantum numbers that function like the N normal mode quantum numbers at low energy. The nominal assignments are used to reconstruct, as much as possible, an organization of the spectrum resembling the usual separation into sequences and progressions. copyright 1996 American Institute of Physics
14. Wildlife forensic science: A review of genetic geographic origin assignment.
Science.gov (United States)
2015-09-01
Wildlife forensic science has become a key means of enforcing legislation surrounding the illegal trade in protected and endangered species. A relatively new dimension to this area of forensic science is to determine the geographic origin of a seized sample. This review focuses on DNA testing, which relies on assignment of an unknown sample to its genetic population of origin. Key examples of this are the trade in timber, fish and ivory and these are used only to illustrate the large number of species for which this type of testing is potentially available. The role of mitochondrial and nuclear DNA markers is discussed, alongside a comparison of neutral markers with those exhibiting signatures of selection, which potentially offer much higher levels of assignment power to address specific questions. A review of assignment tests is presented along with detailed methods for evaluating error rates and considerations for marker selection. The availability and quality of reference data are of paramount importance to support assignment applications and ensure reliability of any conclusions drawn. The genetic methods discussed have been developed initially as investigative tools but comment is made regarding their use in courts. The potential to compliment DNA markers with elemental assays for greater assignment power is considered and finally recommendations are made for the future of this type of testing. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
15. Reflective practice: assessment of assignments in English for Specific Purposes
Directory of Open Access Journals (Sweden)
Galina Kavaliauskiené
2007-10-01
Full Text Available The construct alternative assessment has been widely used in higher education. It is often defined as any type of assessment of learners who provide a response to an assignment. The key features of alternative assessment are active participation of learners in self-evaluation of their performance, and the development of reflective thinking through reflective thinking (Schön, 1983. The success of alternative assessment in language teaching is predetermined by student’s performance and demonstrates learner’s language proficiency in contemporary communicative classrooms. This paper aims at researching the influence of students’ evaluations of various assignments for their linguistic development in English for Specific Purposes (ESP. The study uses learners’ assessment of different assignments and learners’ in-course and post-course written reflections on benefits to language mastery. Learners’ assignments included were contributions to portfolios (dossiers, such as essays and summaries, oral presentations, short impromptu talks, creative tasks, tests, and self-assessment notes (reflections on activities in learning ESP. Findings were obtained for two streams of the project participants. Results showed that self-assessment was beneficial for learners’ linguistic development. The context of learners’ reflections reveals that the attitudes to various assignments are affected by success or failure in students’ performance. Reflective practice might help teachers develop ways of dealing with previously identified difficulties and improve the quality of teaching.
16. Visual words assignment via information-theoretic manifold embedding.
Science.gov (United States)
Deng, Yue; Li, Yipeng; Qian, Yanjun; Ji, Xiangyang; Dai, Qionghai
2014-10-01
Codebook-based learning provides a flexible way to extract the contents of an image in a data-driven manner for visual recognition. One central task in such frameworks is codeword assignment, which allocates local image descriptors to the most similar codewords in the dictionary to generate histogram for categorization. Nevertheless, existing assignment approaches, e.g., nearest neighbors strategy (hard assignment) and Gaussian similarity (soft assignment), suffer from two problems: 1) too strong Euclidean assumption and 2) neglecting the label information of the local descriptors. To address the aforementioned two challenges, we propose a graph assignment method with maximal mutual information (GAMI) regularization. GAMI takes the power of manifold structure to better reveal the relationship of massive number of local features by nonlinear graph metric. Meanwhile, the mutual information of descriptor-label pairs is ultimately optimized in the embedding space for the sake of enhancing the discriminant property of the selected codewords. According to such objective, two optimization models, i.e., inexact-GAMI and exact-GAMI, are respectively proposed in this paper. The inexact model can be efficiently solved with a closed-from solution. The stricter exact-GAMI nonparametrically estimates the entropy of descriptor-label pairs in the embedding space and thus leads to a relatively complicated but still trackable optimization. The effectiveness of GAMI models are verified on both the public and our own datasets.
17. Cognitive Hacking and Digital Government: Digital Identity
Directory of Open Access Journals (Sweden)
Paul Thompson
2004-04-01
Full Text Available Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation systems. Most discussion at the workshop focused on issues related to authentication of users of digital government, but, as implied by the inclusion of a scenario related to ubiquitous identity theft, there was also discussion of problems related to misinformation, including cognitive hacking. Cognitive hacking refers to a computer or information system attack that relies on changing human users' perceptions and corresponding behaviors in order to succeed. This paper describes cognitive hacking, suggests countermeasures, and discusses the implications of cognitive hacking for identity in digital government. In particular, spoofing of government websites and insider misuse are considered.
18. Using Cloud collaboration for writing assignments by students with disabilities: a case study using action research
Directory of Open Access Journals (Sweden)
Kjrsten Keane
2014-02-01
Full Text Available Though separated by geographical distance, a student with disabilities, his advisor, and his writing coach consorted in the Cloud using Google applications to achieve a writing goal. Our scenario demonstrates how emerging technologies can bridge transactional distance and “virtually” supplant face-to-face conferencing around a college writing assignment. Individual levels of technical acumen with digital technology evolved to bridge the psychological and communication space between the student and his instructors. As a result, the telecollaborators developed an efficient coaching process adaptable for all students who need assistance in revising college writing assignments at a distance. Action research frames our discussion of the Cloud collaboration and provides a scaffold for student autonomy. The advantages as well and disadvantages of Cloud collaboration are outlined with reference to the National Institute of Standards of Technology definition of Cloud Computing and the Seven Principles of Universal Course Design.http://dx.doi.org/10.5944/openpraxis.6.1.79
19. Feed-forward segmentation of figure-ground and assignment of border-ownership.
Directory of Open Access Journals (Sweden)
Hans Supèr
Full Text Available Figure-ground is the segmentation of visual information into objects and their surrounding backgrounds. Two main processes herein are boundary assignment and surface segregation, which rely on the integration of global scene information. Recurrent processing either by intrinsic horizontal connections that connect surrounding neurons or by feedback projections from higher visual areas provide such information, and are considered to be the neural substrate for figure-ground segmentation. On the contrary, a role of feedforward projections in figure-ground segmentation is unknown. To have a better understanding of a role of feedforward connections in figure-ground organization, we constructed a feedforward spiking model using a biologically plausible neuron model. By means of surround inhibition our simple 3-layered model performs figure-ground segmentation and one-sided border-ownership coding. We propose that the visual system uses feed forward suppression for figure-ground segmentation and border-ownership assignment.
20. Feed-forward segmentation of figure-ground and assignment of border-ownership.
Science.gov (United States)
Supèr, Hans; Romeo, August; Keil, Matthias
2010-05-19
Figure-ground is the segmentation of visual information into objects and their surrounding backgrounds. Two main processes herein are boundary assignment and surface segregation, which rely on the integration of global scene information. Recurrent processing either by intrinsic horizontal connections that connect surrounding neurons or by feedback projections from higher visual areas provide such information, and are considered to be the neural substrate for figure-ground segmentation. On the contrary, a role of feedforward projections in figure-ground segmentation is unknown. To have a better understanding of a role of feedforward connections in figure-ground organization, we constructed a feedforward spiking model using a biologically plausible neuron model. By means of surround inhibition our simple 3-layered model performs figure-ground segmentation and one-sided border-ownership coding. We propose that the visual system uses feed forward suppression for figure-ground segmentation and border-ownership assignment.
1. Domesticating Digital Game-based Learning
Directory of Open Access Journals (Sweden)
Helga Dís Sigurdardottir
2016-07-01
Full Text Available This paper analyses the use of digital game-based learning (DGBL in schools in Norway. It investigates the types of games used in Norwegian schools and how pupils experience that practice. Digital game-based learning is being widely employed throughout Norway as a result of the increased focus on digital skills in Norwegian education. This paper analyses that development by way of focus group interviews with a total of sixty-four pupils at four schools. Drawing upon domestication and actor-network theory, the paper provides a novel approach to the study of DGBL. The broad empirical investigation into DGBL practices furthermore provides a contribution to scholarly literature on the subject. A noteworthy finding of this study is the diversity of games employed in schools—around 30 different titles— indicating that the choice of games lies at the discretion of individual teachers. Findings from this research show that the domestication of digital game-based learning occurs through the construction of complex game-based learning assemblages. This includes the classroom and home as gaming sites, group work and individual assignments as practices, and PCs and iPads as platforms.
2. DNATCO: assignment of DNA conformers at dnatco.org.
Science.gov (United States)
Černý, Jiří; Božíková, Paulína; Schneider, Bohdan
2016-07-08
The web service DNATCO (dnatco.org) classifies local conformations of DNA molecules beyond their traditional sorting to A, B and Z DNA forms. DNATCO provides an interface to robust algorithms assigning conformation classes called NTC: to dinucleotides extracted from DNA-containing structures uploaded in PDB format version 3.1 or above. The assigned dinucleotide NTC: classes are further grouped into DNA structural alphabet NTA: , to the best of our knowledge the first DNA structural alphabet. The results are presented at two levels: in the form of user friendly visualization and analysis of the assignment, and in the form of a downloadable, more detailed table for further analysis offline. The website is free and open to all users and there is no login requirement. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.
3. The Utility of Writing Assignments in Undergraduate Bioscience
Science.gov (United States)
Libarkin, Julie; Ording, Gabriel
2012-01-01
We tested the hypothesis that engagement in a few, brief writing assignments in a nonmajors science course can improve student ability to convey critical thought about science. A sample of three papers written by students (n = 30) was coded for presence and accuracy of elements related to scientific writing. Scores for different aspects of scientific writing were significantly correlated, suggesting that students recognized relationships between components of scientific thought. We found that students' ability to write about science topics and state conclusions based on data improved over the course of three writing assignments, while the abilities to state a hypothesis and draw clear connections between human activities and environmental impacts did not improve. Three writing assignments generated significant change in student ability to write scientifically, although our results suggest that three is an insufficient number to generate complete development of scientific writing skills. PMID:22383616
4. Integrated project scheduling and staff assignment with controllable processing times.
Science.gov (United States)
Fernandez-Viagas, Victor; Framinan, Jose M
2014-01-01
This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times.
5. Integrated Project Scheduling and Staff Assignment with Controllable Processing Times
Directory of Open Access Journals (Sweden)
Victor Fernandez-Viagas
2014-01-01
Full Text Available This paper addresses a decision problem related to simultaneously scheduling the tasks in a project and assigning the staff to these tasks, taking into account that a task can be performed only by employees with certain skills, and that the length of each task depends on the number of employees assigned. This type of problems usually appears in service companies, where both tasks scheduling and staff assignment are closely related. An integer programming model for the problem is proposed, together with some extensions to cope with different situations. Additionally, the advantages of the controllable processing times approach are compared with the fixed processing times. Due to the complexity of the integrated model, a simple GRASP algorithm is implemented in order to obtain good, approximate solutions in short computation times.
6. A search asymmetry reversed by figure-ground assignment.
Science.gov (United States)
Humphreys, G W; Müller, H
2000-05-01
We report evidence demonstrating that a search asymmetry favoring concave over convex targets can be reversed by altering the figure-ground assignment of edges in shapes. Visual search for a concave target among convex distractors is faster than search for a convex target among concave distractors (a search asymmetry). By using shapes with ambiguous local figure-ground relations, we demonstrated that search can be efficient (with search slopes around 10 ms/item) or inefficient (with search slopes around 30-40 ms/item) with the same stimuli, depending on whether edges are assigned to concave or convex "figures." This assignment process can operate in a top-down manner, according to the task set. The results suggest that attention is allocated to spatial regions following the computation of figure-ground relations in parallel across the elements present. This computation can also be modulated by top-down processes.
7. Lower region: a new cue for figure-ground assignment.
Science.gov (United States)
Vecera, Shaun P; Vogel, Edward K; Woodman, Geoffrey F
2002-06-01
Figure-ground assignment is an important visual process; humans recognize, attend to, and act on figures, not backgrounds. There are many visual cues for figure-ground assignment. A new cue to figure-ground assignment, called lower region, is presented: Regions in the lower portion of a stimulus array appear more figurelike than regions in the upper portion of the display. This phenomenon was explored, and it was demonstrated that the lower-region preference is not influenced by contrast, eye movements, or voluntary spatial attention. It was found that the lower region is defined relative to the stimulus display, linking the lower-region preference to pictorial depth perception cues. The results are discussed in terms of the environmental regularities that this new figure-ground cue may reflect.
8. A Stone Resource Assignment Model under the Fuzzy Environment
Directory of Open Access Journals (Sweden)
Liming Yao
2012-01-01
to tackle a stone resource assignment problem with the aim of decreasing dust and waste water emissions. On the upper level, the local government wants to assign a reasonable exploitation amount to each stone plant so as to minimize total emissions and maximize employment and economic profit. On the lower level, stone plants must reasonably assign stone resources to produce different stone products under the exploitation constraint. To deal with inherent uncertainties, the object functions and constraints are defuzzified using a possibility measure. A fuzzy simulation-based improved simulated annealing algorithm (FS-ISA is designed to search for the Pareto optimal solutions. Finally, a case study is presented to demonstrate the practicality and efficiency of the model. Results and a comparison analysis are presented to highlight the performance of the optimization method, which proves to be very efficient compared with other algorithms.
9. Quality Control Test for Sequence-Phenotype Assignments
Science.gov (United States)
Ortiz, Maria Teresa Lara; Rosario, Pablo Benjamín Leon; Luna-Nevarez, Pablo; Gamez, Alba Savin; Martínez-del Campo, Ana; Del Rio, Gabriel
2015-01-01
Relating a gene mutation to a phenotype is a common task in different disciplines such as protein biochemistry. In this endeavour, it is common to find false relationships arising from mutations introduced by cells that may be depurated using a phenotypic assay; yet, such phenotypic assays may introduce additional false relationships arising from experimental errors. Here we introduce the use of high-throughput DNA sequencers and statistical analysis aimed to identify incorrect DNA sequence-phenotype assignments and observed that 10–20% of these false assignments are expected in large screenings aimed to identify critical residues for protein function. We further show that this level of incorrect DNA sequence-phenotype assignments may significantly alter our understanding about the structure-function relationship of proteins. We have made available an implementation of our method at http://bis.ifc.unam.mx/en/software/chispas. PMID:25700273
10. The ICAP (Interactive Course Assignment Pages Publishing System
Directory of Open Access Journals (Sweden)
Kim Griggs
2008-03-01
Full Text Available The ICAP publishing system is an open source custom content management system that enables librarians to easily and quickly create and manage library help pages for course assignments (ICAPs, without requiring knowledge of HTML or other web technologies. The system's unique features include an emphasis on collaboration and content reuse and an easy-to-use interface that includes in-line help, simple forms and drag and drop functionality. The system generates dynamic, attractive course assignment pages that blend Web 2.0 features with traditional library resources, and makes the pages easier to find by providing a central web page for the course assignment pages. As of December 2007, the code is available as free, open-source software under the GNU General Public License.
11. New techniques in digital holography
CERN Document Server
Picart, Pascal
2015-01-01
A state of the art presentation of important advances in the field of digital holography, detailing advances related to fundamentals of digital holography, in-line holography applied to fluid mechanics, digital color holography, digital holographic microscopy, infrared holography, special techniques in full field vibrometry and inverse problems in digital holography
12. Digital atlas of Oklahoma
Science.gov (United States)
Rea, A.H.; Becker, C.J.
1997-01-01
13. Assignment of stock keeping units to parallel undirectional picking
Directory of Open Access Journals (Sweden)
Matthews, Jason
2015-05-01
Full Text Available An order picking system consisting of a number of parallel unidirectional picking lines is investigated. Stock keeping units (SKUs that are grouped by product type into distributions (DBNs are assigned daily to available picking lines. A mathematical programming formulation and its relaxations is presented. A greedy insertion and a greedy phased insertion are further introduced to obtain feasible results within usable computation times for all test cases. The walking distance of the pickers was shown to decrease by about 22 per cent compared with the current assignment approach. However, product handling and operational risk increases.
14. Statistical methods of spin assignment in compound nuclear reactions
International Nuclear Information System (INIS)
Mach, H.; Johns, M.W.
1984-01-01
Spin assignment to nuclear levels can be obtained from standard in-beam gamma-ray spectroscopy techniques and in the case of compound nuclear reactions can be complemented by statistical methods. These are based on a correlation pattern between level spin and gamma-ray intensities feeding low-lying levels. Three types of intensity and level spin correlations are found suitable for spin assignment: shapes of the excitation functions, ratio of intensity at two beam energies or populated in two different reactions, and feeding distributions. Various empirical attempts are examined and the range of applicability of these methods as well as the limitations associated with them are given. 12 references
15. Statistical methods of spin assignment in compound nuclear reactions
International Nuclear Information System (INIS)
Mach, H.; Johns, M.W.
1985-01-01
Spin assignment to nuclear levels can be obtained from standard in-beam gamma-ray spectroscopy techniques and in the case of compound nuclear reactions can be complemented by statistical methods. These are based on a correlation pattern between level spin and gamma-ray intensities feeding low-lying levels. Three types of intensity and level spin correlations are found suitable for spin assignment: shapes of the excitation functions, ratio of intensity at two beam energies or populated in two different reactions, and feeding distributions. Various empirical attempts are examined and the range of applicability of these methods as well as the limitations associated with them are given
16. Automated Negotiation for Resource Assignment in Wireless Surveillance Sensor Networks
Directory of Open Access Journals (Sweden)
Enrique de la Hoz
2015-11-01
Full Text Available Due to the low cost of CMOS IP-based cameras, wireless surveillance sensor networks have emerged as a new application of sensor networks able to monitor public or private areas or even country borders. Since these networks are bandwidth intensive and the radioelectric spectrum is limited, especially in unlicensed bands, it is mandatory to assign frequency channels in a smart manner. In this work, we propose the application of automated negotiation techniques for frequency assignment. Results show that these techniques are very suitable for the problem, being able to obtain the best solutions among the techniques with which we have compared them.
17. Probabilistic validation of protein NMR chemical shift assignments
International Nuclear Information System (INIS)
Dashti, Hesam; Tonelli, Marco; Lee, Woonghee; Westler, William M.; Cornilescu, Gabriel; Ulrich, Eldon L.; Markley, John L.
2016-01-01
Data validation plays an important role in ensuring the reliability and reproducibility of studies. NMR investigations of the functional properties, dynamics, chemical kinetics, and structures of proteins depend critically on the correctness of chemical shift assignments. We present a novel probabilistic method named ARECA for validating chemical shift assignments that relies on the nuclear Overhauser effect data. ARECA has been evaluated through its application to 26 case studies and has been shown to be complementary to, and usually more reliable than, approaches based on chemical shift databases. ARECA is available online at http://areca.nmrfam.wisc.edu/ http://areca.nmrfam.wisc.edu/
18. A method to assign failure rates for piping reliability assessments
International Nuclear Information System (INIS)
Gamble, R.M.; Tagart, S.W. Jr.
1991-01-01
This paper reports on a simplified method that has been developed to assign failure rates that can be used in reliability and risk studies of piping. The method can be applied on a line-by-line basis by identifying line and location specific attributes that can lead to piping unreliability from in-service degradation mechanisms and random events. A survey of service experience for nuclear piping reliability also was performed. The data from this survey provides a basis for identifying in-service failure attributes and assigning failure rates for risk and reliability studies
19. Single machine scheduling with slack due dates assignment
Science.gov (United States)
Liu, Weiguo; Hu, Xiangpei; Wang, Xuyin
2017-04-01
This paper considers a single machine scheduling problem in which each job is assigned an individual due date based on a common flow allowance (i.e. all jobs have slack due date). The goal is to find a sequence for jobs, together with a due date assignment, that minimizes a non-regular criterion comprising the total weighted absolute lateness value and common flow allowance cost, where the weight is a position-dependent weight. In order to solve this problem, an ? time algorithm is proposed. Some extensions of the problem are also shown.
20. Probabilistic validation of protein NMR chemical shift assignments
Energy Technology Data Exchange (ETDEWEB)
Dashti, Hesam [University of Wisconsin-Madison, Graduate Program in Biophysics, Biochemistry Department (United States); Tonelli, Marco; Lee, Woonghee; Westler, William M.; Cornilescu, Gabriel [University of Wisconsin-Madison, Biochemistry Department, National Magnetic Resonance Facility at Madison (United States); Ulrich, Eldon L. [University of Wisconsin-Madison, BioMagResBank, Biochemistry Department (United States); Markley, John L., E-mail: [email protected], E-mail: [email protected] [University of Wisconsin-Madison, Biochemistry Department, National Magnetic Resonance Facility at Madison (United States)
2016-01-15
Data validation plays an important role in ensuring the reliability and reproducibility of studies. NMR investigations of the functional properties, dynamics, chemical kinetics, and structures of proteins depend critically on the correctness of chemical shift assignments. We present a novel probabilistic method named ARECA for validating chemical shift assignments that relies on the nuclear Overhauser effect data. ARECA has been evaluated through its application to 26 case studies and has been shown to be complementary to, and usually more reliable than, approaches based on chemical shift databases. ARECA is available online at http://areca.nmrfam.wisc.edu/ http://areca.nmrfam.wisc.edu/.
1. Evoked Feelings, Assigned Meanings and Constructed Knowledge Based on Mistakes
Directory of Open Access Journals (Sweden)
Luciane Guimarães Batistella Bianchini
2017-09-01
Full Text Available By means of Piaget's critical clinical method, the study investigated the meanings assigned to mistakes by four students in different activities and interactive situations. The research also analyzed the results of using self-regulatory situations in understanding mistakes initially committed by the students. Data collection instruments consisted of games, video recordings, diaries and interviews. Following intervention, the students were able to recognize their competence, establish positive interactions within the group, and avoid viewing mistakes as obstacles to learning. We concluded that the meanings assigned to mistakes depend on certain variables, among them feelings nurtured by the individuals about themselves, the other, and the object of knowledge.
2. Asymmetry in some common assignment algorithms: the dispersion factor solution
OpenAIRE
T de la Barra; B Pérez
1986-01-01
Many common assignment algorithms are based on Dial's original design to determine the paths that trip makers will follow from a given origin to destination centroids. The purpose of this paper is to show that the rules that have to be applied result in two unwanted properties. The first is that trips assigned from an origin centroid i to a destination j can be dramatically different to those resulting from centroid j to centroid i , even if the number of trips is the same and the network is ...
3. Digital temperature meter
Energy Technology Data Exchange (ETDEWEB)
Glowacki, S
1982-01-01
Digital temperature meter for precise temperature measurements is presented. Its parts such as thermostat, voltage-frequency converter and digital frequency meter are described. Its technical parameters such as temperature range 50degC-700degC, measurement precision 1degC, measurement error +-1degC are given. (A.S.).
4. Changing State Digital Libraries
Science.gov (United States)
Pappas, Marjorie L.
2006-01-01
Research has shown that state virtual or digital libraries are evolving into websites that are loaded with free resources, subscription databases, and instructional tools. In this article, the author explores these evolving libraries based on the following questions: (1) How user-friendly are the state digital libraries?; (2) How do state digital…
5. Digital signage sobre IP
OpenAIRE
2012-01-01
Projecte que versa sobre el disseny i la implementació d'un sistema de Digital Signage (Cartelleria Digital) sobre IP, creant un gestor que permeti controlar de forma remota tot un conjunt de petits dispositius connectats a pantalles que emeten continguts multimèdia com vídeos, imatges, feeds rss...
6. Digital gaming expertise
DEFF Research Database (Denmark)
Toft-Nielsen, Claus
In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within communic......In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within...... communication and game studies there are multiple understandings of how digital expertise is expressed and performed, and subsequently how these expressions and performances can be valued, understood and theorized within the research community. Among other things expertise with and within digital games has......-of-game (Schrøder, 2003) in a three-year-long study of men and women (couples and singles) playing the largest Massively Multiplayer Online Role-Playing Game to date, World of Warcraft. In focusing on how different aspects of gaming expertise are articulated, negotiated, and performed, I aim to illustrate how...
7. The First Digit 1
1075. RESONANCE | December 2013. GENERAL | ARTICLE. Table 2. The first digits distri- bution according to Benford's law. First Frequency. Digit. 1. 30.1 %. 2. 17.6 %. 3. 12.4 %. 4. 9.7 %. 5. 7.9 %. 6. 6.7 %. 7. 5.8 %. 8. 5.1 %. 9. 4.5 % ...
8. Digital Cultural Heritage
NARCIS (Netherlands)
Navarrete, T.; Rizzo, I.; Mignosa, A.
2013-01-01
What is the impact of media technology on the supply and demand of heritage with what is usually described as digitization? This chapter presents the concept of digitization as concerning far more than just the introduction of computers, the development of databases and websites, and the conversion
9. Digital formidling af kulturarv
DEFF Research Database (Denmark)
En af tidens store kulturelle dagsordner drejer sig om digital tilgængeliggørelse af kulturarv. Fortidens spor dukker op i nye former på nettet - næsten alle kulturinstitutioner arbejder med, og befolkningen har fået helt nye muligheder for at se med og deltage. Digital formidling af kulturarv...
10. Digitizing migration heritage
DEFF Research Database (Denmark)
Marselis, Randi
2011-01-01
Museums are increasingly digitizing their collections and making them available to the public on-line. Creating such digital resources may become means for social inclusion. For museums that acknowledge migration history and cultures of ethnic minority groups as important subjects in multiethnic...
11. Beyond Digital Citizenship
Science.gov (United States)
Mitchell, Lynn
2016-01-01
Conversations in middle school about digital citizenship tend to focus on the responsibilities of citizenship and the issues of surveillance, safety, cyberbullying, and internet etiquette. While these are important and essential conversations, digital citizenship education needs to consider youth political identity and democratic participation in…
12. Navigate the Digital Rapids
Science.gov (United States)
Lindsay, Julie; Davis, Vicki
2010-01-01
How can teachers teach digital citizenship when the digital landscape is changing so rapidly? How can teachers teach proper online social interactions when the students are outside their classroom and thus outside their control? Will encouraging students to engage in global collaborative environments land teachers in hot water? These are the…
13. Monetizing Digital Assets
Directory of Open Access Journals (Sweden)
Felician ALECU
2013-04-01
Full Text Available This article covers the options the digital content creators have to monetize their creations. The simplest solution seems to be the winning one, so by enabling the ads, the digital content may be quickly transformed into money with no cost.
DEFF Research Database (Denmark)
Debess, Jeanne Elisabeth; Johnsen, Karen Kirstine; Thomsen, Henrik
on collimation and dose reduction in digital chest radiography Methods and Materials A retrospective study of digital chest radiography is performed to evaluate the primary x-ray tube collimation of the PA and lateral radiographs. Data from one hundred fifty self-reliant female patients between 15 and 55 years...
15. Recurrent infantile digital fibromatosis
African Journals Online (AJOL)
We present a case of an 8-year-old-boy with recurrent infantile digital fibromatosis (IDF) who presented with new ... Keywords: fibrous tumors, inclusion body fibromatosis, infantile digital fibromatosis, spindle cells, Reye tumor .... watch-and-wait strategy for patients with histologically confirmed IDF nodules that do not cause ...
16. Practical digital mammography
Energy Technology Data Exchange (ETDEWEB)
Hashimoto, Beverly E. [Washington Univ., Seattle, WA (United States)]|[Virginia Mason Medical Center, VA (United States)
2008-07-01
This book is meant for the radiologist who is facing the challenge of organizing a digital mammographic imaging center. This text is meant to be a practical book that provides information about digital mammographic physics and equipment which will allow one to intelligently compare technologies and systems. Some of the major challenges include: large expense; rapidly changing technology, and inconsistent connectivity; and finally, need for strong information technology support. The initial conversion cost to digital mammographic imaging is relatively expensive due to the cost of digital mammography hardware, software, and storage. Virtually all other imaging modalities are being converted to purely digital storage and transfer, and the digital trend in mammography is inevitable. Technical advantages of digital mammography are described. However, the improved flexibility in image display and transfer are some of its strongest features. In conclusion, although there are increasing imaging modalities that may be used to evaluate breast disease, mammography will continue to play a key role in detecting breast cancer. To be an effective imager, the radiologist should become familiar with digital mammography and understand its role within the increasing complex structure of breast imaging techniques.
17. Practical digital mammography
International Nuclear Information System (INIS)
Hashimoto, Beverly E.
2008-01-01
This book is meant for the radiologist who is facing the challenge of organizing a digital mammographic imaging center. This text is meant to be a practical book that provides information about digital mammographic physics and equipment which will allow one to intelligently compare technologies and systems. Some of the major challenges include: large expense; rapidly changing technology, and inconsistent connectivity; and finally, need for strong information technology support. The initial conversion cost to digital mammographic imaging is relatively expensive due to the cost of digital mammography hardware, software, and storage. Virtually all other imaging modalities are being converted to purely digital storage and transfer, and the digital trend in mammography is inevitable. Technical advantages of digital mammography are described. However, the improved flexibility in image display and transfer are some of its strongest features. In conclusion, although there are increasing imaging modalities that may be used to evaluate breast disease, mammography will continue to play a key role in detecting breast cancer. To be an effective imager, the radiologist should become familiar with digital mammography and understand its role within the increasing complex structure of breast imaging techniques
18. Educating Digital Citizens
Science.gov (United States)
Tan, Thomas
2011-01-01
Digital citizenship is how educators, citizens, and parents can teach where the lines of cyber safety and ethics are in the interconnected online world their students will inhabit. Aside from keeping technology users safe, digital citizenship also prepares students to survive and thrive in an environment embedded with information, communication,…
19. Digital Rights Management
NARCIS (Netherlands)
Koster, P.; Jonker, Willem; Blanken, Henk; de Vries, A.P.; Blok, H.E.; Feng, L.
2007-01-01
Digital Rights Management, or DRM for short, is a much-discussed topic nowadays. The main reason for this is that DRM technology is often mentioned in the context of protection of digital audio and video content, for example to avoid large scale copying of CDs and DVDs via peer-to-peer networks in
20. Digitalization of daycare institutions
DEFF Research Database (Denmark)
Chimirri, Niklas Alexander
in the intergenerational interaction with as well as the intragenerational interaction among daycare children. To some extent, digital media usage, foremost of tablet computers, has seen a discursive and material normalization across a number Danish daycare institutions before at all clarifying how it could be rendered...... as on situated sociomaterial approaches to critical psychological practice research in order to inquire into possible specificities of digital media device usage: How is this usage similar to and different from interacting via other material-communicative devices in a pedagogical practice? How do digital media......The digitalization of Danish daycare institutions is not only affecting the ways staff is documenting and reporting on its pedagogical work. It also appears to be redefining what pedagogical work itself is about, given the drastic increase in deployment of digital (mobile) media devices...
1. Creative Digital Media Practices
DEFF Research Database (Denmark)
Frølunde, Lisbeth
, 2006, 2009), machinima (machine + cinema + anime, real-time animation captured in games etc.), and the digital storytelling movement. A dialogic perspective on the diversity of digital media practices opens up for understanding the complex evolution of language on socio-historical, cultural......The presentation reviews the interplay of dialogic (Bakhtin, 1981) and multimodal theories on media production practices, with attention to visual communication (Kress and van Leeuwen, 2001, 2006). This theoretical approach aids in reflecting on digital media practices as novel (new) sign systems...... develop a collaborative digital storytelling showcase for their own digital stories about Roskilde University. This course is intended to bring up reflections on the wider phenomenon of contemporary media practices, such as: YouTube, DIY (do-it-yourself) filmmaking or homemade, garage cinema (Jenkins...
2. Digital Technology Entrepreneurship
DEFF Research Database (Denmark)
Giones, Ferran; Brem, Alexander
2017-01-01
Technology entrepreneurship is an established concept in academia. However, recent developments in the context of digital entrepreneurship call for revision and advance- ment. The multiple possible combinations of technology and entrepreneurship have res- ulted in a diversity of phenomena...... with significantly different characteristics and socio-economic impact. This article is focused on the identification and description of technology entrepreneurship in times of digitization. Based on current examples, we identify and describe characterizations of technology entrepreneurship, digital techno- logy...... entrepreneurship, and digital entrepreneurship. With this new delineation of terms, we would like to foster discussion between researchers, entrepreneurs, and policy makers on the impact of digitization on entrepreneurship, and set a future research agenda....
3. Transformation of Digital Ecosystems
DEFF Research Database (Denmark)
Henningsson, Stefan; Hedman, Jonas
2014-01-01
the Digital Ecosystem Technology Transformation (DETT) framework for explaining technology-based transformation of digital ecosystems by integrating theories of business and technology ecosystems. The framework depicts ecosystem transformation as distributed and emergent from micro-, meso-, and macro- level......In digital ecosystems, the fusion relation between business and technology means that the decision of technical compatibility of the offering is also the decision of how to position the firm relative to the coopetive relations that characterize business ecosystems. In this article we develop...... coopetition. The DETT framework consists an alternative to the existing explanations of digital ecosystem transformation as the rational management of one central actor balancing ecosystem tensions. We illustrate the use of the framework by a case study of transformation in the digital payment ecosystem...
4. The digital spine
DEFF Research Database (Denmark)
Ebbesen, Toke Riis
2019-01-01
In the words of the Oxford English Dictionary, a book is 'a portable volume consisting of a series of written, printed, or illustrated pages bound together for ease of reading' (‘book, n.’nd). Yet, the world of books isn’t what it used to be. If differences between media are material differences...... analyze books as digital or even 'post-digital' artifacts (Cramer 2014), while preserving the material dimension of the book artifact. In other words: is there is such a thing as a (post-)digital spine, and how can it be described? This article outlines an answer to this question within an inferential...... (Seiter 2015), and books are produced, distributed and read on various digital media and devices, it is no longer possible to understand digital books on the basis of the material and syntactical features of the codex artifact. It then becomes important to discuss how to conceptualize and subsequently...
5. Digital Tectonic Tools
DEFF Research Database (Denmark)
Schmidt, Anne Marie Due
2005-01-01
Tectonics has been an inherent part of the architectural field since the Greek temples while the digital media is new to the field. This paper is built on the assumption that in the intermediate zone between the two there is a lot to be learned about architecture in general and the digital media...... in particular. A model of the aspects in the term tectonics – epresentation, ontology and culture – will be presented and used to discuss the current digital tools’ ability in tectonics. Furthermore it will be discussed what a digital tectonic tool is and could be and how a connection between the digital...... and tectonic could become a part of the architectural education....
6. Digital forensic standards: international progress
CSIR Research Space (South Africa)
Grobler, MM
2010-05-01
Full Text Available With the explosion of digital crime, digital forensics is more often applied. The digital forensic discipline developed rather rapidly, but up to date very little international standardization with regard to processes, procedures or management has...
7. Measuring digit lengths with 3D digital stereophotogrammetry: A comparison across methods.
Science.gov (United States)
Gremba, Allison; Weinberg, Seth M
2018-05-09
We compared digital 3D stereophotogrammetry to more traditional measurement methods (direct anthropometry and 2D scanning) to capture digit lengths and ratios. The length of the second and fourth digits was measured by each method and the second-to-fourth ratio was calculated. For each digit measurement, intraobserver agreement was calculated for each of the three collection methods. Further, measurements from the three methods were compared directly to one another. Agreement statistics included the intraclass correlation coefficient (ICC) and technical error of measurement (TEM). Intraobserver agreement statistics for the digit length measurements were high for all three methods; ICC values exceeded 0.97 and TEM values were below 1 mm. For digit ratio, intraobserver agreement was also acceptable for all methods, with direct anthropometry exhibiting lower agreement (ICC = 0.87) compared to indirect methods. For the comparison across methods, the overall agreement was high for digit length measurements (ICC values ranging from 0.93 to 0.98; TEM values below 2 mm). For digit ratios, high agreement was observed between the two indirect methods (ICC = 0.93), whereas indirect methods showed lower agreement when compared to direct anthropometry (ICC < 0.75). Digit measurements and derived ratios from 3D stereophotogrammetry showed high intraobserver agreement (similar to more traditional methods) suggesting that landmarks could be placed reliably on 3D hand surface images. While digit length measurements were found to be comparable across all three methods, ratios derived from direct anthropometry tended to be higher than those calculated indirectly from 2D or 3D images. © 2018 Wiley Periodicals, Inc.
8. Computing Logarithms Digit-by-Digit
Science.gov (United States)
Goldberg, Mayer
2005-01-01
In this work, we present an algorithm for computing logarithms of positive real numbers, that bears structural resemblance to the elementary school algorithm of long division. Using this algorithm, we can compute successive digits of a logarithm using a 4-operation pocket calculator. The algorithm makes no use of Taylor series or calculus, but…
9. Single Assignment C (SAC): High Productivity meets High Performance
NARCIS (Netherlands)
Grelck, C.; Zsók, V.; Horváth, Z.; Plasmeijer, R.
2012-01-01
We present the ins and outs of the purely functional, data parallel programming language SaC (Single Assignment C). SaC defines state- and side-effect-free semantics on top of a syntax resembling that of imperative languages like C/C++/C# or Java: functional programming with curly brackets. In
10. Developing Team Skills through a Collaborative Writing Assignment
Science.gov (United States)
Thomas, Theda Ann
2014-01-01
Employers want students who are able to work effectively as members of a team, and expect universities to develop this ability in their graduates. This paper proposes a framework for a collaborative writing assignment that specifically develops students' ability to work in teams. The framework has been tested using two iterations of an action…
11. 47 CFR 90.723 - Selection and assignment of frequencies.
Science.gov (United States)
2010-10-01
... 220-222 MHz Band § 90.723 Selection and assignment of frequencies. (a) Phase II applications for frequencies in the 220-222 MHz band shall specify whether their intended use is for 10-channel nationwide... medical use. Phase II applicants for frequencies for public safety/mutual aid use or emergency medical use...
12. Threat evaluation and weapon assignment decision support: A ...
African Journals Online (AJOL)
... stands within the context of a ground based air defence system (GBADS) at the turn of the twenty first century. However, much of the contents of the paper maye generalized to military environments other than a GBADS one. Keywords: Threat evaluation, weapon assignment, decision support. ORiON Vol. 23 (2) 2007: pp.
13. A Competitive and Experiential Assignment in Search Engine Optimization Strategy
Science.gov (United States)
Clarke, Theresa B.; Clarke, Irvine, III
2014-01-01
Despite an increase in ad spending and demand for employees with expertise in search engine optimization (SEO), methods for teaching this important marketing strategy have received little coverage in the literature. Using Bloom's cognitive goals hierarchy as a framework, this experiential assignment provides a process for educators who may be new…
14. Assignments of rights and obligations under a gas sales contract
International Nuclear Information System (INIS)
Kowch, J.R.M.
1996-01-01
A general overview of the principles of assignment in a gas sales contract was presented. Assignment is a process wherein the rights or obligations under a contract are transferred from one of the contracting parties to a third party. It is, in other words, the introduction of a new party to the original contractual relationship. Under the rights and obligations of a gas sales contract, the most important right of the seller is to have its gas taken and to be paid. Likewise, the most important obligation of the buyer is to take the gas and pay for it. An assignment by either party has the potential to alter the original expectations of the parties or the basis of which they committed to the contract in the first place. Prior to deregulation and unbundling initiatives, gas sellers and buyers could enter a 20 year sales contract and deal exclusively with each other over the entire 20 year term. Since deregulation, there are more players, and a higher level of corporate acquisitions, divestitures, rationalizations, and restructuring. Today, there are greater chances than ever before that the original party to a contract may change, or that certain rights and obligations may be assigned to a third party and affect the expectations under the contract
15. Nursing Distance Learning Course Comparison of Assignments and Examination Scores
Science.gov (United States)
Mundine, Jennifer
2016-01-01
Nursing programs have embraced distance learning in their curricula, but discussion is ongoing about course assignments and grading criteria to increase examination scores in nursing distance learning courses. Because course examinations are a predictor of success on the postgraduate licensing examination (NCLEX-RN), the purpose of this study was…
16. 33 CFR 5.33 - Training, examination, and assignment.
Science.gov (United States)
2010-07-01
... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Training, examination, and... GENERAL COAST GUARD AUXILIARY § 5.33 Training, examination, and assignment. The Commandant will prescribe the type of training, qualifications and examinations required before a member of the Auxiliary shall...
17. Role of magnetic resonance imaging in assigning sex in an ...
African Journals Online (AJOL)
A three years old child with ambiguous genitalia since birth had been referred to Muhimbili National Hospital (MNH),a tertiary referral hospital, in order to be evaluated and assigned sex correctly. Due to periphery location of the referring center, social and economic constraints, the child was not presented earlier. Physical ...
18. Protect Heterogeneous Environment Distributed Computing from Malicious Code Assignment
Directory of Open Access Journals (Sweden)
V. S. Gorbatov
2011-09-01
Full Text Available The paper describes the practical implementation of the protection system of heterogeneous environment distributed computing from malicious code for the assignment. A choice of technologies, development of data structures, performance evaluation of the implemented system security are conducted.
19. Asset Mapping: A Course Assignment and Community Assessment
Science.gov (United States)
Crozier, Mary; Melchior, Florence
2013-01-01
Asset mapping is a relatively new data collection strategy to identify services, staff capacity, programs, resources, values, and other protective factors in a geographic area that can be juxtaposed to risk factors when initiating community planning. A substance abuse prevention course for undergraduates added an assignment of assessing community…
20. Mining Staff Assignment Rules from Event-Based Data
NARCIS (Netherlands)
Ly, Linh Thao; Rinderle, Stefanie; Dadam, Peter; Reichert, Manfred; Bussler, Christoph J.; Haller, Armin
2006-01-01
Process mining offers methods and techniques for capturing process behaviour from log data of past process executions. Although many promising approaches on mining the control flow have been published, no attempt has been made to mine the staff assignment situation of business processes. In this
1. Gamification for Non-Majors Mathematics: An Innovative Assignment Model
Science.gov (United States)
Leong, Siow Hoo; Tang, Howe Eng
2017-01-01
The most important ingredient of the pedagogy for teaching non-majors is getting their engagement. This paper proposes to use gamification to engage non-majors. An innovative game termed as Cover the Hungarian's Zeros is designed to tackle the common weakness of non-majors mathematics in solving the assignment problem using the Hungarian Method.…
2. 9 CFR 355.10 - Assignment of inspectors.
Science.gov (United States)
2010-01-01
... INSPECTION AND CERTIFICATION CERTIFIED PRODUCTS FOR DOGS, CATS, AND OTHER CARNIVORA; INSPECTION... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Assignment of inspectors. 355.10 Section 355.10 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...
3. Homework Assignments to Enhance Student Engagement in Secondary Education
Science.gov (United States)
2013-01-01
Secondary school teachers often complain that their students show a disengaged attitude in class. Students do not prepare for lessons, they show a passive attitude towards classroom activities and they have a limited awareness of their own learning process. Based on a pilot study, four homework assignments were designed, implemented, and evaluated…
4. Application of a Dynamic Programming Algorithm for Weapon Target Assignment
Science.gov (United States)
2016-02-01
evaluation and weapon assignment in maritime combat scenarios. Lloyd also acts as a liaison for the Weapons and Combat Systems Division with the ANZAC...positively identified a number of targets as threats, whether they are an enemy ship (i.e., specifically, its weapon launcher systems) or a directed
5. Linear Optimization of Frequency Spectrum Assignments Across System
Science.gov (United States)
2016-03-01
selection tools, frequency allocation, transmission optimization, electromagnetic maneuver warfare, electronic protection, assignment model 15. NUMBER ...Characteristics Modeled ...............................................................29 Table 10. Antenna Systems Modeled , Number of Systems and...surveillance EW early warning GAMS general algebraic modeling system GHz gigahertz IDE integrated development environment ILP integer linear program
6. Comparison of Categorical Assignments of the BSRI and the PAQ.
Science.gov (United States)
Gaa, John P.; Liberman, Dov
The degree of agreement between the Bem Sex Role Inventory (BSRI) and the Personality Attributes Questionnaire (PAQ) in assigning sex role categories was investigated by administering both instruments to undergraduate education majors. As a result of scoring, subjects were classified as androgynous, masculine, feminine, or undifferentiated. It was…
7. Unintended Cognitive, Affective, and Behavioral Consequences of Group Assignments
Science.gov (United States)
Neu, Wayne A.
2012-01-01
Pedagogical strategies can be thought of as a set of stimuli placed in students' environment to influence their cognition, affect, and behavior. The design of strategies such as group assignments and a comprehensive understanding of their consequences for students should then include an analysis of all three of these elements and the…
8. 28 CFR 345.35 - Assignments to FPI.
Science.gov (United States)
2010-07-01
..., color, religion, ethnic origin, age, or disability. (b) The SOI ordinarily makes assignments based on... course in pre-industrial training or on-the-job training (as available) before promotion to pay grade four. (2) An inmate who has not successfully completed pre-industrial or on-the-job training remains at...
9. Privacy-Preserving Task Assignment in Spatial Crowdsourcing
KAUST Repository
Liu, An
2017-09-20
With the progress of mobile devices and wireless networks, spatial crowdsourcing (SC) is emerging as a promising approach for problem solving. In SC, spatial tasks are assigned to and performed by a set of human workers. To enable effective task assignment, however, both workers and task requesters are required to disclose their locations to untrusted SC systems. In this paper, we study the problem of assigning workers to tasks in a way that location privacy for both workers and task requesters is preserved. We first combine the Paillier cryptosystem with Yao’s garbled circuits to construct a secure protocol that assigns the nearest worker to a task. Considering that this protocol cannot scale to a large number of workers, we then make use of Geohash, a hierarchical spatial index to design a more efficient protocol that can securely find approximate nearest workers. We theoretically show that these two protocols are secure against semi-honest adversaries. Through extensive experiments on two real-world datasets, we demonstrate the efficiency and effectiveness of our protocols.
10. Assigning Main Orientation to an EOH Descriptor on Multispectral Images
Directory of Open Access Journals (Sweden)
Yong Li
2015-07-01
Full Text Available This paper proposes an approach to compute an EOH (edge-oriented histogram descriptor with main orientation. EOH has a better matching ability than SIFT (scale-invariant feature transform on multispectral images, but does not assign a main orientation to keypoints. Alternatively, it tends to assign the same main orientation to every keypoint, e.g., zero degrees. This limits EOH to matching keypoints between images of translation misalignment only. Observing this limitation, we propose assigning to keypoints the main orientation that is computed with PIIFD (partial intensity invariant feature descriptor. In the proposed method, SIFT keypoints are detected from images as the extrema of difference of Gaussians, and every keypoint is assigned to the main orientation computed with PIIFD. Then, EOH is computed for every keypoint with respect to its main orientation. In addition, an implementation variant is proposed for fast computation of the EOH descriptor. Experimental results show that the proposed approach performs more robustly than the original EOH on image pairs that have a rotation misalignment.
11. The Value of Interactive Assignments in the Online Learning Environment
Science.gov (United States)
Florenthal, Bela
2016-01-01
The offerings of Web-based supplemental material for textbooks have been increasingly growing. When deciding to adopt a textbook, instructors examine the added value of the associated supplements, also called "e-learning tools," to enhance students' learning of course concepts. In this study, one such supplement, interactive assignments,…
12. A multiobjective approach towards weapon assignment in a ground ...
African Journals Online (AJOL)
A typical ground-based air defence (GBAD) environment comprises defended assets on the ground which require protection from enemy aircraft entering the defended airspace. ... of computerised threat evaluation and weapon assignment (TEWA) decision support systems (DSSs) within the context of a GBAD system.
13. Preconditions of origin, essence and assignment of strategic managerial accounting
OpenAIRE
Boiko, I.
2010-01-01
The article is devoted to the research of preconditions and necessity of creation strategic managerial accounting in the accounting system of enterprise. There are investigated economic essence and assignment of strategic managerial accounting and substantiated its importance for making strategic decisions on an enterprise.
14. More Districts Factoring Poverty into Student-Assignment Plans
Science.gov (United States)
Zehr, Mary Ann
2010-01-01
A growing number of school districts are trying to break up concentrations of poverty on their campuses by taking students' family income into consideration in school assignments. Some of the districts replaced race with socioeconomic status as a determining indicator after the U.S. Supreme Court ruled in 2007 that using race as the primary factor…
15. Optimal resource assignment in workflows for maximizing cooperation
NARCIS (Netherlands)
Kumar, Akhil; Dijkman, R.M.; Song, Minseok; Daniel, Fl.; Wang, J.; Weber, B.
2013-01-01
A workflow is a team process since many actors work on various tasks to complete an instance. Resource management in such workflows deals with assignment of tasks to workers or actors. In team formation, it is necessary to ensure that members of a team are compatible with each other. When a workflow
16. Three results on frequency assignment in linear cellular networks
Czech Academy of Sciences Publication Activity Database
Chrobak, M.; Sgall, Jiří
2010-01-01
Roč. 411, č. 1 (2010), s. 131-137 ISSN 0304-3975 R&D Projects: GA MŠk(CZ) 1M0545; GA AV ČR IAA100190902 Keywords : frequency assignment * approximation algorithms * online algorithms Subject RIV: BA - General Mathematics Impact factor: 0.838, year: 2010 http://www.sciencedirect.com/science/article/pii/S0304397509006574
17. 36 CFR 292.22 - Land category assignments.
Science.gov (United States)
2010-07-01
... land. (iv) Commercial land. (2) Not later than August 12, 1994, a map or maps displaying the privately... availability of this map or maps in the local newspapers of record. (b) Changes in land category assignment.../grazing land so long as the intended use or development is consistent with the standards in § 292.23 and...
18. Optimal Weight Assignment for a Chinese Signature File.
Science.gov (United States)
Liang, Tyne; And Others
1996-01-01
Investigates the performance of a character-based Chinese text retrieval scheme in which monogram keys and bigram keys are encoded into document signatures. Tests and verifies the theoretical predictions of the optimal weight assignments and the minimal false hit rate in experiments using a real Chinese corpus for disyllabic queries of different…
19. 77 FR 8174 - EPAAR Prescription for Work Assignments
Science.gov (United States)
2012-02-14
... because it does not affect the level of protection provided to human health or the environment. This rulemaking does not involve human health or environmental affects. K. Congressional Review Act The... Prescription for Work Assignments AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY...
20. Covariance NMR Processing and Analysis for Protein Assignment.
Science.gov (United States)
Harden, Bradley J; Frueh, Dominique P
2018-01-01
During NMR resonance assignment it is often necessary to relate nuclei to one another indirectly, through their common correlations to other nuclei. Covariance NMR has emerged as a powerful technique to correlate such nuclei without relying on error-prone peak peaking. However, false-positive artifacts in covariance spectra have impeded a general application to proteins. We recently introduced pre- and postprocessing steps to reduce the prevalence of artifacts in covariance spectra, allowing for the calculation of a variety of 4D covariance maps obtained from diverse combinations of pairs of 3D spectra, and we have employed them to assign backbone and sidechain resonances in two large and challenging proteins. In this chapter, we present a detailed protocol describing how to (1) properly prepare existing 3D spectra for covariance, (2) understand and apply our processing script, and (3) navigate and interpret the resulting 4D spectra. We also provide solutions to a number of errors that may occur when using our script, and we offer practical advice when assigning difficult signals. We believe such 4D spectra, and covariance NMR in general, can play an integral role in the assignment of NMR signals.
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https://www.physicsforums.com/threads/physics-question-regarding-impluse-momentum-and-velocity.278222/
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# Physics Question Regarding Impluse, Momentum, and Velocity.
1. Dec 8, 2008
### Jim4592
I'm not sure exactly sure how to set up this problem...
1. The problem statement, all variables and given/known data
A hockey puck with a mass of 0.160 kg is at rest at the origin (x=0) on a horizontal, frictionless surface at time t=0, a force of 0.250 N is applied to the puck parallel to the X axis, the force is applied until time = 2.00s.
2. Relevant equations
What is the acceleration, position, and speed of the puck at t=2.00 s
3. The attempt at a solution
Impulse (J) = (F) * (∆T)
J = (0.250N)*(2.00s)
J = .5 NS
I know J = ∆ Momentum (P) ; and P = Mass * Velocity, but i'm not exactly sure how to calculate what it wants me to find.
Any help will be appreciated.
Thanks,
Jim
2. Dec 8, 2008
### Staff: Mentor
You have the force. What does that tell you about the acceleration?
You found the impulse. What does that tell you about the speed at t=2.00s?
Use a little kinematics to find the distance traveled.
3. Dec 8, 2008
### Jim4592
I think i get it but aren't completly sure
so using P=mv
.5 NS = 0.160 kg * v
v= 3.125 m/s ?
A = (3.125 m/s) / 2.00s
A = 1.563 m/s^2
and position:
X(final) = X(initial) + V(i)t + 1/2 at^2
X = 1/2 * (1.563 m/s) * (2.00s)^2
X = 3.125m
Could someone confirm that is correct please?
4. Dec 8, 2008
All good!
5. Dec 8, 2008
### Jim4592
wow that was alot easier than i thought. Thanks for your help.
Similar Discussions: Physics Question Regarding Impluse, Momentum, and Velocity.
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https://team.inria.fr/dracula/fr/research/
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# Recherche
### Presentation
Dracula is a joint research team between Inria, Université Claude Bernard Lyon 1 (UCBL) and CNRS (Institut Camille-Jordan (ICJ, UMR 5208) and Laboratoire de Biologie et Modélisation de la Cellule (LBMC, UMR 5239)).
The Dracula project is devoted to multi-scale modeling in biology and medicine, and more specifically to the development of tools and methods to describe multi-scale processes in biology and medicine. Applications include normal and pathological hematopoiesis (for example leukemia), immune response, and other biological processes, like: tissue renewal, morphogenesis, atherosclerosis, prion disease, hormonal regulation of food intake, and so on. Multi-scale modeling implies simultaneous modeling of several levels of descriptions of biological processes: intra-cellular networks (molecular level), cell behavior (cellular level), dynamics of cell populations (organ or tissue) with the control by other organs (organism) (see Figure ). Such modeling represents one of the major challenges in modern science due to its importance and because of the complexity of biological phenomena and of the presence of very different interconnected scales.
Although multi-scale modeling holds a great potential for biology and medicine, and despite the fact that a variety of techniques exists to deal with such problems, the complexity of the systems poses new challenges and needs the development of new tools. Moreover, different biological questions usually require different types of multi-scale modeling. The expected results of these studies are numerous. On one hand, they will shed new light on the understanding of specific biological and medical questions (for instance, what is the behavior of hematopoietic stem cells under pathological conditions? Or how to efficiently stimulate an immune response in order to design new vaccines?). On the other hand, the modeling methods developed here for specific processes are relevant to study other complex biological systems. We pay a special attention on developing methods that are not restricted to one or two applications.
An important part of our researches is performed in close collaboration with biologists and physicians in order to stay in contact with the biological and medical goals. The presence, within the project, of a biologist (Olivier Gandrillon) who has acquired over the years the know-how required for interacting with mathematicians is probably one of the main assets of the project. He participates actively in many tasks of our program, stimulates interactions between members of the project and biologists, and everyone benefits from his expertise in molecular and cell biology.
### Keywords
Multi-scale modeling; Hybrid modeling; Mathematical Biology; Computational Biology; Immune response modeling; Normal and pathological hematopoiesis; Multi-scale cancer modeling; Regulatory networks; Reaction-diffusion equation; Structured partial differential equations; Delay differential equations; Agent-based modeling; Dynamical systems.
### Executive summary
Stem cells are essential for development and keep the maintenance of many tissues homeostasis. They are characterized by their ability to self-renew as well as to produce differentiated cells. They vary enormously, for each organ, in their proliferation capacity, their potency to produce different cell lineage and their response to various environmental cues. How a cell will react to a given external signal does not depend only on its current state but also on its environment. Understanding the effect of cell-to-cell heterogeneity and the spatial organization of cell populations is therefore necessary to help keeping the normal function of an organ.
We develop mathematical tools and methods to study cell population dynamics and other biological processes: stability of steady sates, existence of bifurcations, kinetic properties, spatial organization, in finely detailed cell populations. The main tools we use are hybrid discrete-continuous models, reaction-diffusion equations, structured models (in which the population is endowed with relevant structures or traits), delay differential systems, agent-based models. Our team has acquired an international expertise in the fields of analysis of reaction-diffusion and structured equations, particularly integro-differential and delay differential equations.
The mathematical methods we develop are not restricted to hematopoietic system (Research axis 2), and immune response (Research axis 3), rather we apply them in many other biological phenomena, for example: tissue renewal, morphogenesis, prion disease, atherosclerosis, hormonal regulation of food intake, cancer, and others.
### Project-team positioning
The focus of this objective is the development, analysis and application of hybrid discrete-continuous, reaction-diffusion and structured partial differential models. The structured equations allow a fine description of a population as some structures (age, maturity, intracellular content) change with time. In many cases, structured equations can be partially integrated to yield integro-differential equations (ordinary or partial differential equations involving non-local integral terms), time-delay differential or time-delay partial differential, or coupled differential-difference models. Analysis of integro-differential and time-delay systems deals with existence of solutions and their stability. Applications are found in the study of normal and pathological hematopoietic system (Research axis 2), immune response (Research axis 3), morphogenesis, prion disease, cancer development and treatment, and generally in tissue renewal problems. Models based on structured equations are especially useful to take into account the effect of finite time cells take to divide, die or become mature. Reaction-diffusion equations are used in order to describe spatial distribution of cell populations. It is a well developed area of research in our team which includes qualitative properties of travelling waves for reaction-diffusion systems with or without delay, and complex nonlinear dynamics.
Our team has developed a solid expertise in mathematical analysis of reaction-diffusion with or without delay and structured equations (in particular, delay differential equations) and one of the most prolific. Other major groups are the teams of Benoit Perthame (Pierre et Marie CURIE University and Mamba, Paris, https://team.inria.fr/mamba/fr/), Emmanuel Grenier (Ecole normale supérieure de Lyon and NUMED, https://www.inria.fr/en/teams/numed), Odo Diekmann (Utrecht University, The Netherlands, https://www.uu.nl/staff/ODiekmann), Avner Friedman (The Ohio State University, USA, https://people.math.osu.edu/friedman.158/), Jianhong Wu (York University, Canada, http://liam.lab.yorku.ca/), Glenn Webb (Vanderbilt University, Nashville, USA, https://as.vanderbilt.edu/math/bio/glenn-webb), Philip K. Maini (University of Oxford, England, https://people.maths.ox.ac.uk/maini/), Mark Chaplain (University of St Andrews, Scotland, http://www.mcs.st-andrews.ac.uk/~majc/), Nicola Bellomo (University of Turin, Italy, http://staff.polito.it/nicola.bellomo/index.html). Most of the members of all these groups and of our team belong to the same mathematical community working on partial differential equations and dynamical systems with applications to biology and medicine.
### Collaborations
• University of Toronto, Canada; Mathematical analysis and applications of reaction-diffusion equations (more than 30 joint papers).
• Institute of Problems of Mechanical Engineering, St.Petersburg, Russia; Dynamics of cell renewal (more than 10 joint papers).
• Department of Cell and Molecular Biology and Department of Forensic Medicine, Stockholm, Sweden; Dynamics of cell generation and turnover (3 joint papers).
• Universities of Tlemcen (Algeria) and Marrakech (Morocco); Delay differential equations (7 joint papers)
### Executive summary
Hematopoiesis is a complex process that begins with hematopoietic stem cells (HSCs) and results in formation of mature cells: red blood cells, white cells and platelets. Blood cells are produced in the bone marrow, from where mature cells are released into the blood stream. Hematopoiesis is based on a balance between cell proliferation (including self-renewal), differentiation and apoptosis. The choice between these three possibilities is determined by intra-cellular regulatory networks and by numerous control mechanisms in the bone marrow or carried out by other organs. Intra-cellular regulatory networks are complex biochemical reactions involving proteins, enzymes and signalling molecules. The deregulation of hematopoiesis can result in numerous blood diseases including leukemia (a cancer of blood cells). One important type of leukemia is Chronic Myeloid Leukemia (CML). The strong tyrosine kinase activity of the BCR-ABL protein is the basis for the main cell effects that are observed in CML: significant proliferation, anti-apoptotic effect, disruption of stroma adhesion properties. This explains the presence in CML blood of a very important number of cells belonging to the myeloid lineage, at all stages of maturation.
Multi-scale modeling in hematopoiesis holds a great potential. A variety of techniques exists to deal with this problem. However, the complexity of the system poses new difficulties and leads to the development of new tools. The expected results of this study are numerous. On one hand, it will shed new light on the different physiological mechanisms that converge toward the continuous regeneration of blood cells, for example: the understanding of deregulation of erythropoiesis (the process of red blood cell production) under drug treatments (this can lead to lack of red blood cells (anemia), or a surplus of red blood cells), the dynamic of leukemic cells under the action of drugs and the control of their resistance to these treatments.
### Project team positioning
Multi-scale modeling of hematopoiesis is one of the key points of the project that has started in the early stage of the Dracula team. Investigated by all the team members, it took many years of close discussion with biologists to get the best understanding of the key role played by the most important molecules, hormones, kinase cascade, cell communication up to the latest knowledge. One of the important questions here is to identify particular biological mechanisms (intracellular regulation, control mechanisms) and to integrate them in the different models. Our main work consisted in the development of a hybrid (continuous/discrete) model for red blood cell progenitor proliferation, survival/death, differentiation, and migration. Cells are modeled as discrete objects, and the extracellular medium is described by continuous equations for extracellular concentrations. This is to our knowledge the most complete model for erythropoiesis to date, and the only one using a multi-scale formalism. Other models published by our group and others for hematopoiesis are population-based models, mostly population structured equations (transport partial differential equations or delay differential equations). The interest in modeling hematopoiesis dates back to the 70’s and two groups have been responsible for most of development in the past 40 years: Markus Loeffer’s team in Leipzig, Germany (Wichmann et al. 1976, in Mathematical Models in Medicine) and Michael Mackey’s team at McGill University, Montreal, Canada (Mackey 1978, Blood). Our model differs from population based models in that the regulation is directly modeled at the molecular level (See Figure ) rather than acting on rates at the population level. Thus we can take into account non-predictable effects of interactions between different molecular pathways and between cells that would otherwise be lost in the global population rates.
Regarding modeling leukemia, we concentrated on Chronic Myeloid Leukemia (CML) and its treatment. We considered models based on ordinary differential equations for the action of the main proteins involved in CML (as BCR-ABL protein), and of transport equations (with or without delay, physiologically structured or not) to represent healthy and leukemic cell populations, take into account many interactions between proteins (especially BCR-ABL), cells (anti-apoptotic effect, etc.). The development of models for CML allowed us to interact with Franck Nicolini in Lyon (Centre Hospitalier de Lyon) and Doron Levy (Maryland University, http://www.math.umd.edu/~dlevy/). Different schools developed models for CML and its treatment. The three leading groups are the ones of Franziska Michor (Harvard School of public health, http://michorlab.dfci.harvard.edu/), Ingo Roeder (Institute for Medical Informatics and Biometry, Dresden, https://tu-dresden.de/med/mf/imb/das-institut) and Michael Mackey (McGill University, http://www.mcgill.ca/mathematical-physiology-lab/).
### Collaborations
Members of the team have worked for several years in collaboration with biologists (François Morlé, University Lyon 1) and hematologists (Charles Dumontet, Lyon and Mark Koury, Nashville, http://www.hematology.org/Thehematologist/Authors/298.aspx) on the Modelling of normal and pathological hematopoiesis .
The work on modeling Leukemia is based on two major collaborations: firstly, an ongoing (since 2011) mathematical collaboration with the University of Maryland through the program Associate Teams Inria project, “Modelling Leukemia” (http://dracula.univ-lyon1.fr/modelling_leukemia.php). Secondly, an ongoing (since 2012) collaboration with a clinician from Hospices Civils de Lyon (Dr. F.E. Nicolini). In this framework, we shall have soon access to the data of the clinical trial PETALs ( $2×100$ patients).
### Executive summary
Vaccination represents a worldwide health, social and economical challenge as it has allowed the eradication or the strong containment of several devastating diseases over the past century. However to date, most of the effective vaccines rely on the generation of neutralizing antibody responses and such vaccines have proven largely unsuccessful in the prevention against some pathogens, such as HIV or malaria. In such cases, vaccines geared towards the generation of CD8 T cell immunity may provide a better protection. The generation of memory CD8 T cells following antigenic immunization is a long process (lasting up to month in murine preclinical models), therefore strongly slowing the process of vaccine monitoring in preclinical studies. Thus, the dynamical modeling of the CD8 T cell immune response both at the cellular and molecular levels should provide an important tool to better understand the dynamics of the response and to speed-up the process and reduce costs of vaccine development.
However, currently published cellular models of the immune response are either over-simplified, not predicting important parameters of this response, or too complicated for most of their parameters to be accessible for experimental measurements, thus impeding their biological validation. Dynamical models of the CD8 T cell response at the molecular level are very scarce and there is no multi-scale model of the immune response giving insights into both the regulation at the molecular scale and the consequences on cell population dynamics.
The objective of this research axis is therefore to develop a predictive multi-scale model of the CD8 T cell response, by confronting the model at different stages to in vivo-acquired experimental data, in order to be able to investigate the influence of early molecular events on cell population dynamics few days or weeks later.
### Project-team positioning
We are aiming at building and analyzing a multi-scale model of the CD8 T cell immune response, from the molecular to the cellular and potentially organismal scale. This consists in describing the dynamics at each scale with relevant formalisms as well as the careful description of the couplings between scales.
Only few research groups are actually working on the CD8 T cell immune response around the world, and none of them deals with multi-scale modeling of this response. A network developed around Alan Perelson’s work in theoretical immunology in the last decades, at Los Alamos National Laboratory, and involves mainly people in various US universities or institutes. In Europe, Rob De Boer’s group (http://theory.bio.uu.nl/rdb/) of theoretical immunology in Utrecht, Netherlands, is the historical leader in the CD8 T cell dynamics modeling. We considered the models developed in these groups when we started our project, and we contributed to improve them by using nonlinearities accounting for cell population interactions to regulate the response. Also, our initial focus was on the generation of memory cells associated with vaccine development so we modeled CD8 T cell responses against influenza and vaccinia viruses, whereas other groups usually consider LCMV in its chronic form.
Ron Germain’s group at the NIH, and Grégoire Altan-Bonnet in subsequent works, focused on the molecular regulation of the CD4 and CD8 T cell immune responses. In particular, they built the Simmune software, which allows the modeling and simulation of molecular interactions (https://www.niaid.nih.gov/research/simmune-project). This software is not really devoted to multi-scale modeling yet it provides an interesting tool to describe molecular interactions. Since our aim is to couple molecular and cellular scales at the tissue level, and we do not want to consider large networks but rather small-simplified informative interaction networks, we are confident that our approach is complementary of these works.
Within Inria project-teams, NUMED develops multi-scale approaches for biological problems, and MAMBA and MONC (https://team.inria.fr/monc/) mention models of cancer progression and treatment including immune responses. In the first case the methodology is similar, and collaborations between NUMED and DRACULA already exist (both teams are located in Lyon), but applications differ. In the second case, MAMBA and MONC are mainly focused on cancer modeling and up to now are motivated by including an action of the immune system in the fight against cancer, which is very different from what we are developing. However, both modeling approaches are complementary and could lead to interactions, in particular in the light of recent advances in medical research pointing towards an important role – and high expectations – of the immune reaction in fighting cancers. Finally, SISTM (https://www.inria.fr/en/teams/sistm) also focuses on the modeling of the immune response, mainly against HIV, but the motivation is very similar to ours: the objective is to provide tools and methods in order to efficiently develop vaccines. They consider the CD4 T cell response instead of the CD8 T cell response, and biostatistics to achieve their goals instead of multi-scale models, yet even though there is no interaction between SISTM and DRACULA at this moment our methods and objectives are close enough to foreshadow future collaborations.
### Collaborations
On this topic our main collaborators are members of Jacqueline Marvel’s team in Lyon in the CIRI (Centre International de Recherche en Infectiologie INSERM U1111): Dr. Jacqueline Marvel, head of the team, Dr. Christophe Arpin (CR CNRS), and other technicians and engineers of the team. They are all immunologists, specialists of the CD8 T cell response and of the generation of memory CD8 T cells.
We also interact with private companies: AltraBio (http://www.altrabio.com/), that provides tools for data analysis, and CosmoTech, that develops a modeling and simulating platform that should allow transferring our model on an easy-to-use platform devoted to commercial uses.
### Reminder of the objectives given for the last evaluation
The aim of this project is the development of modern tools for multi-scale modeling in biological phenomena. During the period 2014-2017, the objectives we had fixed were to develop modern tools for multi-scale modeling of biological phenomena, as detailed hereafter:
1. Multi-scale modeling of erythropoiesis, the process of red blood cell production, in order to describe normal, stress, and pathological erythropoiesis, using mathematical and computational models. This led to:
2. The modeling of hemoglobin instability in dialysis patients: Thomas Lepoutre has been progressively taking part in this theme through a collaboration with P. Kim (University of Sydney, Australia);
3. Multi-scale modeling of the CD8 T cell immune response, in order to develop a predictive model of the CD8 T cell response, by confronting the model at different stages to in vivo-acquired experimental data;
4. Population dynamics modeling, with the aim to develop general mathematical tools to study them. The main tools we were using were structured equations, in which the cell population is endowed with relevant structures, or traits. We identified limitations in using these formalisms, this is why we started developing multi-scale approaches;
5. Modeling of Chronic Myeloid Leukemia (CML) treatment, using ordinary differential equations models. Our team had already developed a first model of mutant leukemic cells being resistant to chemotherapy. A next step would be to identify the parameters using experimental data;
6. Multi-scale modeling carried out on the basis of hybrid discrete-continuous models, where dissipative particle dynamics (DPD) are used in order to describe individual cells and relatively small cell populations, partial differential equations (PDE) are used to describe concentrations of bio-chemical substances in the extracellular matrix, and ordinary differential equations for intracellular regulatory networks (Figure ). An emphasis would be made on developing codes that are both flexible and powerful enough to implement variants of the model, perform simulations, produce desired outputs, and provide tools for analysis; to do so:
7. We planned to contribute to a recent project named chronos, whose code (written in C++) represents heterogeneous populations of individual cells evolving in time and interacting physically and biochemically, and the objective is to make the code flexible enough to implement different formalisms within the same model, so that different components of the model can be represented in the most appropriate way;
8. Partial differential equations (PDE) analysis, with a focus on reaction-diffusion equations, transport equations (hyperbolic PDEs) in which the structure can be age, maturity, protein concentration, etc., with particular cases where transport equations are reduced to delay differential equations (DDE).
### Comments on these objectives over the evaluation period
We have had strong contributions to objectives , , , , and consequently to objective , as well as to objective , as mentioned in previous sections. These contributions represented the core of the team’s research activity over the evaluation period, as stressed by our publications. It is however noticeable that multi-scale modeling of the immune response and of pathological hematopoiesis (leukemia) has come to represent a proportionally more important part of our activity.
Objective has been cancelled few months after the previous evaluation, following meetings with clinicians who did not show any particular interest in our approaches. The modeling of chronic myeloid leukemia instead took a bigger part of the team’s research activity, both project being at the time coordinated by Thomas Lepoutre.
Objective has been pursued, the project chronos evolved to a better defined project SiMuScale that is currently being developed and aims at structuring the team’s activity and providing a simulation platform that could be adapted to various biological questions necessitating multi-scale modeling.
### Objectives for the next four years
The main objectives for the next four years are to continue to improve the 3 previous points: 1) Mathematical and computational modeling for cell population dynamics; 2) Multi-scale modeling of hematopoiesis and leukemia; 3) Multi-scale modeling of the immune response. In addition, we will pursue our effort to develop a simulation platform for multi-scale models (SiMuScale) and we intend to develop the use of mixed effect models and other statistical approaches to deal with the challenges offered by modern biology, in particular the generation of single cell data.
## Les résultats
#### Mathematical models describing the interaction between cancer and immune cells in the lymph node
To study the interplay between tumor progression and the immune response, we develop in [article] two new models describing the interaction between cancer and immune cells in the lymph node. The first model consists of partial differential equations (PDEs) describing the populations of the different types of cells. The second one is a hybrid discrete-continuous model integrating the mechanical and biochemical mechanisms that define the tumor-immune interplay in the lymph node. We use the continuous model to determine the conditions of the regimes of tumor-immune interaction in the lymph node. While we use the hybrid model to elucidate the mechanisms that contribute to the development of each regime at the cellular and tissue levels. We study the dynamics of tumor growth in the absence of immune cells. Then, we consider the immune response and we quantify the effects of immunosuppression and local EGF concentration on the fate of the tumor.
#### WASABI: a dynamic iterative framework for gene regulatory network inference
Background Inference of gene regulatory networks from gene expression data has been a long-standing and notoriously difficult task in systems biology. Recently, single-cell transcriptomic data have been massively used for gene regulatory network inference, with both successes and limitations. In the work [article], we propose an iterative algorithm called WASABI, dedicated to inferring a causal dynamical network from time-stamped single-cell data, which tackles some of the limitations associated with current approaches. We first introduce the concept of waves, which posits that the information provided by an external stimulus will affect genes one-by-one through a cascade, like waves spreading through a network. This concept allows us to infer the network one gene at a time, after genes have been ordered regarding their time of regulation. We then demonstrate the ability of WASABI to correctly infer small networks, which have been simulated in silico using a mechanistic model consisting of coupled piecewise-deterministic Markov processes for the proper description of gene expression at the single-cell level. We finally apply WASABI on in vitro generated data on an avian model of erythroid differentiation. The structure of the resulting gene regulatory network sheds a new light on the molecular mechanisms controlling this process. In particular, we find no evidence for hub genes and a much more distributed network structure than expected. Interestingly, we find that a majority of genes are under the direct control of the differentiation-inducing stimulus. Conclusions Together, these results demonstrate WASABI versatility and ability to tackle some general gene regulatory networks inference issues. It is our hope that WASABI will prove useful in helping biologists to fully exploit the power of time-stamped single-cell data.
#### A multiscale model of platelet-fibrin thrombus growth in the flow
Thrombosis is a life-threatening clinical condition characterized by the obstruction of blood flow in a vessel due to the formation of a large thrombus. The pathogenesis of thrombosis is complex because the type of formed clots depends on the location and function of the corresponding blood vessel. To explore this phenomenon, we develop in [article] a novel multiscale model of platelet-fibrin thrombus growth in the flow. In this model, the regulatory network of the coagulation cascade is described by partial differential equations. Blood flow is introduced using the Navier–Stokes equations and the clot is treated as a porous medium. Platelets are represented as discrete spheres that migrate with the flow. Each platelet can attach to the thrombus, aggregate, become activated, express proteins on its surface, detach, and/or become non-adhesive. The interaction of platelets with blood flow is captured using the Immersed Boundary Method (IBM). We use the model to investigate the role of flow conditions in shaping the dynamics of venous and arterial thrombi. We describe the formation of red and white thrombi under venous and arterial flow respectively and highlight the main characteristics of each type. We identify the different regimes of normal and pathological thrombus formation depending on flow conditions.
#### Mathematical modeling of platelet production
• In [article], we analyze the existence of oscillating solutions and the asymptotic convergence for a nonlinear delay differential equation arising from the modeling of platelet production. We consider four different cell compartments corresponding to different cell maturity levels: stem cells, megakaryocytic progenitors, megakaryocytes, and platelets compartments, and the quantity of circulating thrombopoietin (TPO), a platelet regulation cytokine.
• In [article], we analyze the stability of a differential equation with two delays originating from a model for a population divided into two subpopulations, immature and mature, and we apply this analysis to a model for platelet production. The dynamics of mature individuals is described by the following nonlinear differential equation with two delays: $x\prime \left(t\right)=–\lambda x\left(t\right)+g\left(x\left(t–{\tau }_{1}\right)\right)–g\left(x\left(t–{\tau }_{1}–{\tau }_{2}\right)\right){e}^{-\lambda {\tau }_{2}}$ . The method of $D$ -decomposition is used to compute the stability regions for a given equilibrium. The center manifold theory is used to investigate the steady-state bifurcation and the Hopf bifurcation. Similarly, analysis of the center manifold associated with a double bifurcation is used to identify a set of parameters such that the solution is a torus in the pseudo- phase space. Finally, the results of the local stability analysis are used to study the impact of an increase of the death rate γ or of a decrease of the survival time ${\tau }_{2}$ of platelets on the onset of oscillations. We show that the stability is lost through a small decrease of survival time (from $8.4$ to 7 days), or through an important increase of the death rate (from $0.05$ to $0.625$ days ${}^{–1}$ ).
• In [article], we analyze the stability of a system of differential equations with a threshold-defined delay arising from a model for platelet production. We consider a maturity-structured population of megakaryocyte progenitors and an age-structured population of platelets, where the cytokine thrombopoietin (TPO) increases the maturation rate of progenitors. Using the quasi-steady-state approximation for TPO dynamics and the method of characteristics, partial differential equations are reduced to a system of two differential equations with a state-dependent delay accounting for the variable maturation rate. We start by introducing the model and proving the positivity and boundedness of the solutions. Then we use a change of variables to obtain an equivalent system of two differential equations with a constant delay, from which we prove existence and uniqueness of the solution. As linearization around the unique positive steady state yields a transcendental characteristic equation of third degree, we introduce the main result, a new framework for stability analysis on models with fixed delays. This framework is then used to describe the stability of the megakaryopoiesis with respect to its parameters. Finally, with parameters being obtained and estimated from data, we give an example in which oscillations appear when the death rate of progenitors is increased 10-fold.
#### Nonlinear analysis of a model for yeast cell communication
In [article], we study the non-linear stability of a coupled system of two non-linear transport-diffusion equations set in two opposite half-lines. This system describes some aspects of yeast pairwise cellular communication, through the concentration of some protein in the cell bulk and at the cell boundary. We show that it is of bistable type, provided that the intensity of active molecular transport is large enough. We prove the non-linear stability of the most concentrated steady state, for large initial data, by entropy and comparison techniques. For small initial data we prove the self-similar decay of the molecular concentration towards zero. Informally speaking, the rise of a dialog between yeast cells requires enough active molecular transport in this model. Besides, if the cells do not invest enough in the communication with their partner, they do not respond to each other; but a sufficient initial input from each cell in the dialog leads to the establishment of a stable activated state in both cells.
#### Alzheimer’s disease and prion: An in vitro mathematical model
Alzheimer’s disease ( $AD$ ) is a fatal incurable disease leading to progressive neuron destruction. $AD$ is caused in part by the accumulation in the brain of $A\beta$ monomers aggregating into oligomers and fibrils. Oligomers are amongst the most toxic structures as they can interact with neurons via membrane receptors, including $Pr{P}^{c}$ proteins. This interaction leads to the misconformation of $Pr{P}^{c}$ into pathogenic oligomeric prions, $Pr{P}^{ol}$ . In [article], we develop a model describing in vitro $A\beta$ polymerization process. We include interactions between oligomers and $Pr{P}^{c}$ , causing the misconformation of $Pr{P}^{c}$ into $Pr{P}^{ol}$ . The model consists of nine equations, including size structured transport equations, ordinary differential equations and delayed differential equations. We analyse the well-posedness of the model and prove the existence and uniqueness of solutions of our model using Schauder fixed point theorem and Cauchy-Lipschitz theorem. Numerical simulations are also provided to give an illustration of the profiles that can be obtained with this model.
#### Calibration, Selection and Identifiability Analysis of a Mathematical Model of the in vitro Erythropoiesis in Normal and Perturbed Contexts
The in vivo erythropoiesis, which is the generation of mature red blood cells in the bone marrow of whole organisms, has been described by a variety of mathematical models in the past decades. However, the in vitro erythropoiesis, which produces red blood cells in cultures, has received much less attention from the modelling community. In the paper [article], we propose the first mathematical model of in vitro erythropoiesis. We start by formulating different models and select the best one at fitting experimental data of in vitro erythropoietic differentiation obtained from chicken erythroid progenitor cells. It is based on a set of linear ODE, describing 3 hypothetical populations of cells at different stages of differentiation. We then compute confidence intervals for all of its parameters estimates, and conclude that our model is fully identifiable. Finally, we use this model to compute the effect of a chemical drug called Rapamycin, which affects all states of differentiation in the culture, and relate these effects to specific parameter variations. We provide the first model for the kinetics of in vitro cellular differentiation which is proven to be identifiable. It will serve as a basis for a model which will better account for the variability which is inherent to the experimental protocol used for the model calibration.
#### Model-based assessment of the role of uneven partitioning of molecular content on heterogeneity and regulation of differentiation in CD8 T-cell immune responses
Activation of naive CD8 T-cells can lead to the generation of multiple effector and memory subsets. Multiple parameters associated with activation conditions are involved in generating this diversity that is associated with heterogeneous molecular contents of activated cells. Although naive cell polarisation upon antigenic stimulation and the resulting asymmetric division are known to be a major source of heterogeneity and cell fate regulation, the consequences of stochastic uneven partitioning of molecular content upon subsequent divisions remain unclear yet. In [article], we aim at studying the impact of uneven partitioning on molecular-content heterogeneity and then on the immune response dynamics at the cellular level. To do so, we introduce a multiscale mathematical model of the CD8 T-cell immune response in the lymph node. In the model, cells are described as agents evolving and interacting in a 2D environment while a set of differential equations, embedded in each cell, models the regulation of intra and extracellular proteins involved in cell differentiation. Based on the analysis of in silico data at the single cell level, we 1 show that immune response dynamics can be explained by the molecular-content heterogeneity generated by uneven partitioning at cell division. In particular, uneven partitioning acts as a regulator of cell differentiation and induces the emergence of two coexisting sub-populations of cells exhibiting antagonistic fates. We show that the degree of unevenness of molecular partitioning, along all cell divisions, affects the outcome of the immune response and can promote the generation of memory cells.
#### Spatial lymphocyte dynamics in lymph nodes predicts the cytotoxic T-Cell frequency needed for HIV infection control
The surveillance of host body tissues by immune cells is central for mediating their defense function. In vivo imaging technologies have been used to quantitatively characterize target cell scanning and migration of lymphocytes within lymph nodes (LNs). The translation of these quantitative insights into a predictive understanding of immune system functioning in response to various perturbations critically depends on computational tools linking the individual immune cell properties with the emergent behavior of the immune system. By choosing the Newtonian second law for the governing equations, we developed in [article] a broadly applicable mathematical model linking individual and coordinated T-cell behaviors. The spatial cell dynamics is described by a superposition of autonomous locomotion, intercellular interaction, and viscous damping processes. The model is calibrated using in vivo data on T-cell motility metrics in LNs such as the translational speeds, turning angle speeds, andmeandering indices. Themodel is applied to predict the impact of T-cell motility on protection against HIV infection, i.e., to estimate the threshold frequency of HIV-specific cytotoxic T cells (CTLs) that is required to detect productively infected cells before the release of viral particles starts. With this, it provides guidance for HIV vaccine studies allowing for the migration of cells in fibrotic LNs.
#### Drugs modulating stochastic gene expression affect the erythroid differentiation process
To better understand the mechanisms behind cells decision-making to differentiate, we assessed in [article] the influence of stochastic gene expression (SGE) modulation on the erythroid dif- ferentiation process. It has been suggested that stochastic gene expression has a role in cell fate decision-making which is revealed by single-cell analyses but studies dedicated to demonstrate the consistency of this link are still lacking. Recent observations showed that SGE significantly increased during differentiation and a few showed that an increase of the level of SGE is accompanied by an increase in the differentiation process. However, a con- sistent relation in both increasing and decreasing directions has never been shown in the same cellular system. Such demonstration would require to be able to experimentally manipulate simultaneously the level of SGE and cell differentiation in order to observe if cell behavior matches with the current theory. We identified three drugs that modulate SGE in primary erythroid progenitor cells. Both Artemisinin and Indomethacin decreased SGE and reduced the amount of differentiated cells. On the contrary, a third component called MB-3 simultaneously increased the level of SGE and the amount of differentiated cells. We then used a dynamical modelling approach which confirmed that differentiation rates were indeed affected by the drug treatment. Using single-cell analysis and modeling tools, we provide experimental evidence that, in a physiologically relevant cellular system, SGE is linked to differentiation.
#### Stochastic gene expression with a multistate promoter: breaking down exact distributions
We consider in [article] a stochastic model of gene expression in which transcription depends on a multistate promoter, including the famous two-state model and refractory promoters as special cases, and focus on deriving the exact stationary distribution. Building upon several successful approaches, we present a more unified viewpoint that enables us to simplify and generalize existing results. In particular, the original jump process is deeply related to a multivariate piecewise-deterministic Markov process that may also be of interest beyond the biological field. In a very particular case of promoter configuration, this underlying process is shown to have a simple Dirichlet stationary distribution. In the general case, the corresponding marginal distributions extend the well-known class of Beta products, involving complex parameters that directly relate to spectral properties of the promoter transition matrix. Finally, we illustrate these results with biologically plausible examples.
#### Cell generation dynamics underlying naive T-cell homeostasis in adult humans
Thymic involution and proliferation of naive T-cells both contribute to shaping the naive T-cell repertoire as humans age, but a clear understanding of the roles of each throughout a human life span has been difficult to determine. By measuring nuclear bomb test-derived 14 C in genomic DNA, we determined in [article] the turnover rates of CD4 + and CD8 + naive T-cell populations and defined their dynamics in healthy individuals ranging from 20 to 65 years of age. We demonstrate that naive T-cell generation decreases with age because of a combination of declining peripheral division and thymic production during adulthood. Concomitant decline in T-cell loss compensates for decreased generation rates. We investigated putative mechanisms underlying age-related changes in homeostatic regulation of CD4+ naive T-cell turnover, using mass cytometry to profile candidate signaling pathways involved in T-cell activation and proliferation relative to CD31 expression, a marker of thymic proximity for the CD4+ naive T-cell population. We show that basal nuclear factor kB (NF-kB) phosphory-lation positively correlated with CD31 expression and thus is decreased in peripherally expanded naive T-cell clones. Functionally, we found that NF-kB signaling was essential for naive T-cell proliferation to the homeostatic growth factor interleukin (IL)-7, and reduced NF-kB phosphorylation in CD4 + CD31 − naive T cells is linked to reduced homeostatic proliferation potential. Our results reveal an age-related decline in naive T-cell turnover as a putative regulator of naive T-cell diversity and identify a molecular pathway that restricts proliferation of peripherally expanded naive T-cell clones that accumulate with age.
#### Erythroid differentiation displays a peak of energy consumption concomitant with glycolytic metabolism rearrangements
Our previous single-cell based gene expression analysis pointed out significant variations of LDHA level during erythroid differentiation. Deeper investigations highlighted that a metabolic switch occurred along differentiation of erythroid cells. More precisely we showed in [article] that self-renewing progenitors relied mostly upon lactate-productive glycolysis, and required LDHA activity, whereas differentiating cells, mainly involved mitochondrial oxidative phosphorylation (OXPHOS). These metabolic rearrangements were coming along with a particular temporary event, occurring within the first 24h of erythroid differentiation. The activity of glycolytic metabolism and OXPHOS rose jointly with oxgene consumption dedicated to ATP production at 12-24h of the differentiation process before lactate-productive glycolysis sharply fall down and energy needs decline. Finally, we demonstrated that the metabolic switch mediated through LDHA drop and OXPHOS upkeep might be necessary for erythroid differentiation. We also discuss the possibility that metabolism, gene expression and epigenetics could act together in a circular manner as a driving force for differentiation.
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https://www.physicsforums.com/threads/can-the-water-100-oc-gain-latent-heat-energy-from-the-same-temperature-object.31581/
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Can the water (100 oC) gain latent heat energy from the same temperature object?
1. Jun 18, 2004
no idea
can the water (100 oC) gain latent heat energy from the same temperature object?
2. Jun 18, 2004
expscv
i dont think so, it vary with the object , the size of it.
3. Jun 18, 2004
Staff: Mentor
heat flow
No. Heat flow requires a temperature difference.
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http://openstudy.com/updates/4f7925dee4b0ddcbb89e9975
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## calyne 3 years ago If f(x) + x^2 * f(x) = 10 and f(1)=2, find f'(1). Delete Cancel Submit
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1. yash007
• 3 years ago
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check ur ques. again its wrong it does not satisfy for f(1)=2 in the main equation
2. calyne
• 3 years ago
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well that's the friggen problem verbatim from the textbook
3. calyne
• 3 years ago
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OH pellet
4. calyne
• 3 years ago
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it's not sorry geez sorry it's f(x) + x^2 * f(x)^3 = 10 the second f(x) term is cubed
5. AnimalAin
• 3 years ago
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Maybe rearrange the problem a bit....$y+x^2y=10\implies y=\frac{10}{1+x^2}$I don't think your problem meets the specified conditions.
6. yash007
• 3 years ago
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is ur anwer 2/5??
7. calyne
• 3 years ago
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it's -16/13 that's the answer in the book
8. calyne
• 3 years ago
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animalain - it's y + (x^2)(y^3) = 10
9. AnimalAin
• 3 years ago
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Yeah, I got that. Trying to figure out my strategy....
10. yash007
• 3 years ago
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yeah its done
11. calyne
• 3 years ago
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...
12. AnimalAin
• 3 years ago
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How did you do it?
13. yash007
• 3 years ago
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differentiate it n then put x=1 in equation u'll get the result
14. yash007
• 3 years ago
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is that done??
15. AnimalAin
• 3 years ago
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$y + (x^2)(y^3) = 10\implies y'+2xy^3+3x^2y^2y'=0$$\implies y'(1+3x^2y^2)=-2xy^3\implies y'=\frac{-2xy^3}{1+3x^2y^2}$$\implies y'(1)=\frac{-16}{13}$Got it. Need to practice my calculus a little more....LOL
16. yash007
• 3 years ago
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all the best..:)
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http://mathhelpforum.com/discrete-math/167618-symmetric-difference-proof-2.html
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1. $\displaystyle \text{let} \ x \in (A \cap B^{c}) \cup (B \cap A^{c})$
$\displaystyle \text{then} \ x \in (A \cap B^{c}) \ \text{or} \ x \in (B \cap A^{c})$
$\text{so} \ (x \in A \ \text{and} \ x \in B^{c}) \ \text{or} \ (x \in B \ \text{and} \ x \in A^{c})$
$\Big((x \in A \ \text{and} \ x \in B^{c}) \ \text{or} \ x \in B \Big) \ \text{and} \ \Big((x \in A \ \text{and} \ x \in B^{c}) \ \text{or} \ x \in A^{c} \Big)$
$\Big((x \in A \ \text{or} \ x\in B) \ \text{and} \ (x \in B^{c} \ \text{or} \ x \in B) \Big) \ \text{and} \ \Big((x \in A \ \text{or} \ x \in A^{c}) \ \text{and} \ (x \in B^{c} \ \text{or} \ x \in A^{c}) \Big)$
$\Big((x \in (A \cup B) \cap U \Big) \ \text{and} \ \Big(x \in U \cap (B^{c} \cup A^{c}) \Big)$
$x \in (A \cup B) \ \text{and} \ x \in (A \cap B)^{c}$
$x \in (A \cup B) \cap (A \cap B)^{c}$
2. as this seems to be a great solution I am not supposed to be using anything besides the basic set theory laws
3. Random Variable's solution is actually very nice since the proof doesn't involve knowledge of any laws or theorems - just the basic definitions. It's probably worth it for you to review his argument. The argument using the laws is much quicker and simpler than this argument (as are most arguments that use already established results).
4. Originally Posted by dwsmith
$(A\cup B)- (A\cap B)=(A\cup B)\cap (A\cap B)^c=(A\cup B)\cap (A^c\cup B^c)=...$
Use distributive law here.
What will you get?
$[(A\cup B)\cap A^c]\cup [(A\cup B)\cap B^c]=(B\cap A^c)\cup (A\cap B^c)=(B-A)\cup (A-B)$
Here is the result. If you would have just tried to distribute, you may have had the answer by using the laws per your request.
5. I was having trouble with your notation versus mine, I just couldn't translate your solution/hints into my notation
6. You were using / and I was using -. I am just used to using A-B for what is in A but not in B.
7. I was talking more about the compliment c here
the variations of De Morgan I learned don't use c so I was having trouble switching from one to the other
Page 2 of 2 First 12
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https://forum.allaboutcircuits.com/threads/pic-12f508-gp2-no-output.173478/
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# pic 12f508 GP2 no output
#### ytandy100
Joined Oct 25, 2019
9
i bought some new pic 12f508 chips for a project and found that i could not output on pin 2 , i have looked on various forums and tried all the answers i could find but none worked , i have included the program so you can see what i have and tell me where i went wrong please .
Code:
; GP2 Test program
list p=112f508
#include p12f508.inc
__CONFIG 0X0FEA
;
ORG 0
MOVWF OSCCAL
OPTION 0XDF ;11011111
;Note: If the T0CS bit is set to ‘1’, it will override
;the TRIS function on the T0CKI pin.
;bit 5 T0CS: Timer0 Clock Source Select bit
;1 = Transition on T0CKI pin (overrides TRIS on the T0CKI pin)
;0 = Transition on internal instruction cycle clock, FOSC/4
;5.3 TRIS Registers
;The Output Driver Control register is loaded with the
;contents of the W register by executing the TRIS f
;instruction. A ‘1’ from a TRIS register bit puts the corresponding
;output driver in a High-Impedance mode. A
;‘0’ puts the contents of the output data latch on the
;selected pins, enabling the output buffer. The exceptions
;are RB3/GP3, which is input only and the T0CKI
;pin, which may be controlled by the OPTION register.
;See Register 4-3 and Register 4-4.
SETUP MOVLW 0XC0 ;set all 6 bits as output even 3 in only pin
TRIS GPIO
CLRF GPIO
MOVLW 0X00
MOVWF 0X18
NEXT MOVF 0X18,W
INCF 0X18,F
MOVWF GPIO
; BSF GPIO,2 ;to try direct control of port bit
CALL DELAY
; BCF GPIO,2 ;to try direct control of port bit
GOTO NEXT
DELAY MOVLW 0X01 ;LONG TIME COUNT (7)
MOVWF 0X15
T0 MOVLW 0X80 ;MED TIME COUNT (00)
MOVWF 0X16
T1 MOVLW 0X00 ;SHORT TIME COUNT (00)
MOVWF 0X17
T2 DECFSZ 0X17,F
GOTO T2
DECFSZ 0X16,F
GOTO T1
DECFSZ 0X15,F
GOTO T0
RETLW 0
END
Moderators note : used code tags
Last edited by a moderator:
#### bertus
Joined Apr 5, 2008
22,097
Hello,
Is this correct : list p=112f508
Or should it be : list p=12f508
Bertus
#### jpanhalt
Joined Jan 18, 2008
11,088
Rge 12F508 doesn't use Banks.
#### jpanhalt
Joined Jan 18, 2008
11,088
Line 39 loads GPIO with 0 then goes to delay and does that again. 0x18 does get incremented, and eventually moves to GPIO, but how long does the delay work out to be? The flash may be too quick.
What happens if you implement lines 40 and 42 and forget about line 38?
Have you stepped through the code in a simulator?
Last edited:
#### ytandy100
Joined Oct 25, 2019
9
thank you for replying , it should be list p=12f508 but it didnt change anything .
#### ytandy100
Joined Oct 25, 2019
9
View attachment 219768
Line 39 loads GPIO with 0 then goes to delay and does that again.
What happens if you implement lines 40 and 42?
thank you for replying , line 39 is out putting contents of 0X18 which is just a counter , that peice of code works as i have LEDs on all 6 pins and only GP2 and GP3 dont work and GP3 is an input only pin but i had to try it , 40 and 42 do nothing .
#### ytandy100
Joined Oct 25, 2019
9
View attachment 219768
Line 39 loads GPIO with 0 then goes to delay and does that again. 0x18 does get incremented, and eventually moves to GPIO, but how long does the delay work out to be? The flash may be too quick.
What happens if you implement lines 40 and 42 and forget about line 38?
Have you stepped through the code in a simulator?
in the simulator the option reg always goes to 0X00 but that shouldnt effect GP2 and everything else seems to work as it should that is GPIO is counting up , the delay is slow enough that i can see GP0 , GP1 , ? ,X , GP4 , GP5 , i have also tried turning the LEDs around and connecting to positive , still no change on GP2 .
#### ytandy100
Joined Oct 25, 2019
9
in the simulator the option reg always goes to 0X00 but that shouldnt effect GP2 and everything else seems to work as it should that is GPIO is counting up , the delay is slow enough that i can see GP0 , GP1 , ? ,X , GP4 , GP5 , i have also tried turning the LEDs around and connecting to positive , still no change on GP2 .
ok , im back again , when i switched to simulator i didnt read the warning and tried to use the chip which didnt work so switched to mplab sim to get results , when i switched back to programmer i got this -
PICkit 3 Connected.
PK3Err0045: You must connect to a target device to use PICkit
3.
The target has invalid calibration data (20).
i then did this
Programming...
Programming/Verify complete
and all outputs now work , any idea why something changed , i tried three chips and no GP2 out then a slight goof and this one works , i have been trying for days to get this working .
#### ytandy100
Joined Oct 25, 2019
9
thank you for all replys , i wouldnt have tried sim and then made a booby that destroyed calibration code at 0X1FF which made the GP2 pin work as output (yes really) , i tried the same using the on chip sim and ignored warnings again and when i go back and reprogram the chip GP2 worked as output , when i tried using pickit3 to reset calibration data GP2 stopped working as output , 0X00 , 0X1F worked (didnt try all just a few) but 0X20 stopped again and the original value was 0X26 , hope this info helps some in the future.
i still dont know what is happening , just that it is
#### ytandy100
Joined Oct 25, 2019
9
Code:
; GP2 Test program
list p=12f508
#include p12f508.inc
__CONFIG 0X0FEA
;
ORG 0
MOVWF OSCCAL
MOVLW 0 ;CALIBRATION DATA WORKS O.K.. WITH THIS HERE
;i dont know what is using W reg but it upsets GP2
OPTION 0XDF ;11011111
;Note: If the T0CS bit is set to ‘1’, it will override
;the TRIS function on the T0CKI pin.
;bit 5 T0CS: Timer0 Clock Source Select bit
;1 = Transition on T0CKI pin (overrides TRIS on the T0CKI pin)
;0 = Transition on internal instruction cycle clock, FOSC/4
;5.3 TRIS Registers
;The Output Driver Control register is loaded with the
;contents of the W register by executing the TRIS f
;instruction. A ‘1’ from a TRIS register bit puts the corresponding
;output driver in a High-Impedance mode. A
;‘0’ puts the contents of the output data latch on the
;selected pins, enabling the output buffer. The exceptions
;are RB3/GP3, which is input only and the T0CKI
;pin, which may be controlled by the OPTION register.
;See Register 4-3 and Register 4-4.
SETUP MOVLW 0XC0 ;set all 6 bits as output even 3 in only pin
TRIS GPIO
CLRF GPIO
MOVLW 0X00
MOVWF 0X18
NEXT MOVF 0X18,W
INCF 0X18,F
MOVWF GPIO
; BSF GPIO,2 ;to try direct control of port bit
CALL DELAY
; BCF GPIO,2 ;to try direct control of port bit
GOTO NEXT
DELAY MOVLW 0X01 ;LONG TIME COUNT (7)
MOVWF 0X15
T0 MOVLW 0X80 ;MED TIME COUNT (00)
MOVWF 0X16
T1 MOVLW 0X00 ;SHORT TIME COUNT (00)
MOVWF 0X17
T2 DECFSZ 0X17,F
GOTO T2
DECFSZ 0X16,F
GOTO T1
DECFSZ 0X15,F
GOTO T0
RETLW 0
; MOVLW 0X06
END
#### ytandy100
Joined Oct 25, 2019
9
im back , one last time , i will put up the whole code again but it is only a small change
#### jpanhalt
Joined Jan 18, 2008
11,088
If you had given a decent description of the problem, as in your post #6 originally, we might have been of more help.
I started with the 12F508 many years ago and am quite familiar with it. I used the osc. calibration to fine tune it. Obviously, you realized that GP3 is input only. As for the correction in code, I am anxious to see it.
#### ytandy100
Joined Oct 25, 2019
9
im back , one last time , i will put up the whole code again but it is only a small change
If you had given a decent description of the problem, as in your post #6 originally, we might have been of more help.
I started with the 12F508 many years ago and am quite familiar with it. I used the osc. calibration to fine tune it. Obviously, you realized that GP3 is input only. As for the correction in code, I am anxious to see it.
it is in post number 10 , i just added a MOVLW 0 after the MOVWF osccal , i still dont know how or why the W reg affects anything to do with the output but at least it works now .
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https://code.adonline.id.au/index-match-instead-of-vlookup/
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Dear Internet Explorer user: Your browser is no longer supported
Please switch to a modern browser such as Microsoft Edge, Mozilla Firefox or Google Chrome to view this website's content.
# INDEX MATCH instead of VLOOKUP
INDEX MATCH represents a much better way to search for data in Excel tables than VLOOKUP because this combination is much more versatile.
One of the irritating problems with Microsoft Excel’s VLOOKUP function is that it relies upon the search term being in the first column of the table where the result is.
This is very inconvenient and can complicate table design.
I’ve previously posted an article describing how to use INDEX and MATCH to search multiple parameters. Now I will show you how to use INDEX and MATCH functions to replace VLOOKUP altogether when searching for single parameters. This will enable you to match a search string from any column.
For this demonstration, I shall use previous data.
## Example Data
This is the table from my previous post where the formatted table is called “Loans”:
Let’s say that I have a second table with dates in a column called “Date of Loan”. I want to search the “Loans” table for the amount of money that was lent on 20 November 2014 by matching it to the date in my new table.
I cannot use a VLOOKUP because my search string (“20/11/2014”) is in Column B. The following code, whist syntactically correct, produces a #N/A error because “20/11/2014” doesn’t appear in Column A of the “Loans” table.
=VLOOKUP([Date of Loan], Loans, COLUMN(Loans[Amount]), FALSE)
The solution is as follows:
=INDEX(Loans[Amount],MATCH([@[Date of Loan]],Loans[Date], 0))
## Understanding the formula
This formula can be read as follows:
=INDEX({A},MATCH({B},{C}, 0))
where:
• {A} = Reference to the column where the answer can be found
• {B} = Reference to the search string in the current table
• {C} = Column in the other table where the matching search term can be found
This type of formula can be used in all the same situations as a VLOOKUP.
## Conclusion
Whilst the use of INDEX and MATCH code may appear to be more complicated than VLOOKUP at first, this combination is much more versatile. In fact, some have described multiple advantages when using INDEX and MATCH with cell references.
Hopefully this post has helped you understand the basics of INDEX and MATCH.
One response to “INDEX MATCH instead of VLOOKUP”
On 23 January 2015, Clem Stanyon wrote:
<a href="" title=""> <b> <blockquote cite=""> <code> <em> <i> <q cite=""> <strike> <strong>
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https://math.stackexchange.com/questions/963299/true-or-false-a-relative-maximum-or-minimum-must-occur-at-a-critical-point
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# True or false? A relative maximum or minimum must occur at a critical point.
I'm taking calculus one and I have to determine if this statement is true or false.
A relative maximum or minimum must occur at a critical point.
I believe it is false. The answer key says it is true so I am curious if I am right (low probability) or if I can get this clarified (the answer key has always been right when I thought it was wrong).
For example for y = $\frac{1}{x}$ there is a critical point at x=0 (because the derivative at this point does not exist) even though there is no relative maximum or minimum (or is there?).
I think if the statement was "A relative maximum or minimum must occur at a critical point when the derivative at that point exists."
• A critical point is when the derivative is 0, not when it doesn't exist. There is no critical point at x=0. – Loocid Oct 8 '14 at 5:25
• Hmm then there is a lot of wrong information out on the internet if what you say is true.mathwords.com/c/critical_point.htm or tutorial.math.lamar.edu/Classes/CalcI/CriticalPoints.aspx – Alex Oct 8 '14 at 5:27
• Apologies, you are correct. But your source also says: "But may be neither". – Loocid Oct 8 '14 at 5:30
• Thanks for pointing that out. Didn't notice that. – Alex Oct 8 '14 at 5:30
• Its interesting that Wikipedia states critical points are only at 0's and doesn't mention when it doesn't exist, and they reference "Calculus: A Complete Course". Would be interesting to see if that's actually what they say in the book. – Loocid Oct 8 '14 at 5:34
It depends on what definition of "critical point" you are using. If you mean the same thing as "stationary point" (i.e., a point where the derivative exists and equals zero), then you are right, but not for the reason that you give (see below). However, some people use the phrase "critical point" also for a point where the function $f$ is defined, but not its derivative $f'$ (including endpoints of an interval in the domain $D_f$), and if this is the definition used in your course, then you are wrong.
In your example, $f(x)=1/x$ is undefined at $x=0$, so it doesn't even make sense to talk about maximum or minimum there.
Consider instead the absolute value function $f(x)=|x|$, which has a minimum at $x=0$ despite the fact that $x=0$ is not a stationary point ($f'(0)$ doesn't exist).
[On the other hand, if $f'(a)$ exists and $f$ has a local max/min at $a$, then $a$ must be a stationary point (i.e., $f'(a)=0$).]
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https://worldwidescience.org/topicpages/e/excitation+systems.html
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#### Sample records for excitation systems
1. Excitation system testing in HPP 'Uvac'
Directory of Open Access Journals (Sweden)
Milojčić Nemanja
2011-01-01
Full Text Available The excitation system of hydro unit in HPP 'Uvac' and results of testings of excitation system performed for achieving of unit's mathematical model are presented in this paper. Description of excitation system equipment, parameters of regulators and results obtained after testings are presented. The presented results showed that the regulators are properly adjusted and that the excitation system is completely functional and reliable.
2. Excited states in biological systems
International Nuclear Information System (INIS)
Cilento, G.; Zinner, K.; Bechara, E.J.H.; Duran, N.; Baptista, R.C. de; Shimizu, Y.; Augusto, O.; Faljoni-Alario, A.; Vidigal, C.C.C.; Oliveira, O.M.M.F.; Haun, M.
1979-01-01
Some aspects of bioluminescence related to bioenergetics are discussed: 1. chemical generation of excited species, by means of two general processes: electron transference and cyclic - and linear peroxide cleavage; 2. biological systems capable of generating excited states and 3. biological functions of these states, specially the non-emissive ones (tripletes). The production and the role of non-emissive excited states in biological systems are analysed, the main purpose of the study being the search for non-emissive states. Experiences carried out in biological systems are described; results and conclusions are given. (M.A.) [pt
3. Fission fragment excited laser system
Science.gov (United States)
McArthur, David A.; Tollefsrud, Philip B.
1976-01-01
A laser system and method for exciting lasing action in a molecular gas lasing medium which includes cooling the lasing medium to a temperature below about 150 K and injecting fission fragments through the lasing medium so as to preferentially excite low lying vibrational levels of the medium and to cause population inversions therein. The cooled gas lasing medium should have a mass areal density of about 5 .times. 10.sup.-.sup.3 grams/square centimeter, relaxation times of greater than 50 microseconds, and a broad range of excitable vibrational levels which are excitable by molecular collisions.
4. Effects of noise in excitable systems
International Nuclear Information System (INIS)
Lindner, B.; Garcia-Ojalvo, J.; Neiman, A.; Schimansky-Geier, L.
2004-01-01
We review the behavior of theoretical models of excitable systems driven by Gaussian white noise. We focus mainly on those general properties of such systems that are due to noise, and present several applications of our findings in biophysics and lasers. As prototypes of excitable stochastic dynamics we consider the FitzHugh-Nagumo and the leaky integrate-and-fire model, as well as cellular automata and phase models. In these systems, taken as individual units or as networks of globally or locally coupled elements, we study various phenomena due to noise, such as noise-induced oscillations, stochastic resonance, stochastic synchronization, noise-induced phase transitions and noise-induced pulse and spiral dynamics. Our approach is based on stochastic differential equations and their corresponding Fokker-Planck equations, treated by both analytical calculations and/or numerical simulations. We calculate and/or measure the rate and diffusion coefficient of the excitation process, as well as spectral quantities like power spectra and degree of coherence. Combined with a multiparametric bifurcation analysis of the corresponding cumulant equations, these approaches provide a comprehensive picture of the multifaceted dynamical behaviour of noisy excitable systems
5. Equivalent non-Gaussian excitation method for response moment calculation of systems under non-Gaussian random excitation
International Nuclear Information System (INIS)
Tsuchida, Takahiro; Kimura, Koji
2015-01-01
Equivalent non-Gaussian excitation method is proposed to obtain the moments up to the fourth order of the response of systems under non-Gaussian random excitation. The excitation is prescribed by the probability density and power spectrum. Moment equations for the response can be derived from the stochastic differential equations for the excitation and the system. However, the moment equations are not closed due to the nonlinearity of the diffusion coefficient in the equation for the excitation. In the proposed method, the diffusion coefficient is replaced with the equivalent diffusion coefficient approximately to obtain a closed set of the moment equations. The square of the equivalent diffusion coefficient is expressed by the second-order polynomial. In order to demonstrate the validity of the method, a linear system to non-Gaussian excitation with generalized Gaussian distribution is analyzed. The results show the method is applicable to non-Gaussian excitation with the widely different kurtosis and bandwidth. (author)
6. Response moments of dynamic systems under non-Gaussian random excitation by the equivalent non-Gaussian excitation method
International Nuclear Information System (INIS)
Tsuchida, Takahiro; Kimura, Koji
2016-01-01
Equivalent non-Gaussian excitation method is proposed to obtain the response moments up to the 4th order of dynamic systems under non-Gaussian random excitation. The non-Gaussian excitation is prescribed by the probability density and the power spectrum, and is described by an Ito stochastic differential equation. Generally, moment equations for the response, which are derived from the governing equations for the excitation and the system, are not closed due to the nonlinearity of the diffusion coefficient in the equation for the excitation even though the system is linear. In the equivalent non-Gaussian excitation method, the diffusion coefficient is replaced with the equivalent diffusion coefficient approximately to obtain a closed set of the moment equations. The square of the equivalent diffusion coefficient is expressed by a quadratic polynomial. In numerical examples, a linear system subjected to nonGaussian excitations with bimodal and Rayleigh distributions is analyzed by using the present method. The results show that the method yields the variance, skewness and kurtosis of the response with high accuracy for non-Gaussian excitation with the widely different probability densities and bandwidth. The statistical moments of the equivalent non-Gaussian excitation are also investigated to describe the feature of the method. (paper)
7. Semiconductor-machine system for controlling excitation of synchronous medium power generators
Energy Technology Data Exchange (ETDEWEB)
Vrtikapa, G
1982-01-01
A system for controlling excitation (ARP-29/1) is described which was developed at the ''Nikola Tesla'' institute (Czechoslavakia) for rebuilding the Zvornik hydroelectric plant with 30 MV X A units. The system corresponds to the modern level of automation and considers positive characteristics of existing equipment, it is easily included in a technological process, has small dimensions and is easily installed during overhaul of a electric generating plant, and it allows one to obtain good economic results. Two years of use have confirmed the high reliability and quality of the excitation. The excitation control system consists of synchronous motor, excitation system, automatic control of voltage, manual control of excitation unit, unit for automatic following and switching, relay automatic device with protection and warning. The excitation system of the generator has: thyristor rectifier, thyristor converter, a bridge with thyristor control unit, machine excitation generator, switch for demagnetization. The excitation system is supplied from an electric power network or from a three phase generator with permanent magnets.
8. Analysis about modeling MEC7000 excitation system of nuclear power unit
Science.gov (United States)
Liu, Guangshi; Sun, Zhiyuan; Dou, Qian; Liu, Mosi; Zhang, Yihui; Wang, Xiaoming
2018-02-01
Aiming at the importance of accurate modeling excitation system in stability calculation of nuclear power plant inland and lack of research in modeling MEC7000 excitation system,this paper summarize a general method to modeling and simulate MEC7000 excitation system. Among this method also solve the key issues of computing method of IO interface parameter and the conversion process of excitation system measured model to BPA simulation model. At last complete the simulation modeling of MEC7000 excitation system first time in domestic. By used No-load small disturbance check, demonstrates that the proposed model and algorithm is corrective and efficient.
9. Power system stabilization by superconducting magnetic energystorage connected to rotating exciter
OpenAIRE
Mitani, Yasunori; Tsuji, K
1993-01-01
The authors describe a combination of a rotating exciter and a superconducting magnetic energy storage (SMES) system for efficient power system stabilization. A SMES system connected to an exciter rotating with a turbine-rotor shaft is proposed. The exciter is installed exclusively to supply current for the SMES. Since electrical power output from the SMES is converted into a mechanical torque of the generator directly by the exciter, it is expected that power swings of the generator will be ...
10. Programmable logic controller based synchronous motor excitation system
Directory of Open Access Journals (Sweden)
Janda Žarko
2011-01-01
Full Text Available This paper presents a 3.5 MW synchronous motor excitation system reconstruction. In the proposed solution programmable logic controller is used to control motor, which drives the turbo compressor. Comparing to some other solutions that are used in similar situations, the proposed solution is superior due to its flexibility and usage of mass-production hardware. Moreover, the implementation of PLC enables easy integration of the excitation system with the other technological processes in the plant as well as in the voltage regulation of 'smart grid' system. Also, implementation of various optimization algorithms can be done comfortably and it does not require additional investment in hardware. Some experimental results that depict excitation current during motor start-up, as well as, measured static characteristics of the motor, were presented.
11. Excited, bound and resonant positron-atom systems
International Nuclear Information System (INIS)
Bromley, M W J; Mitroy, J
2010-01-01
Calculations have demonstrated that eleven neutral atoms can bind positrons, while many more can bind positronium. This is a short review of recent progress made in understanding some of the underlying mechanisms. The emphasis here being on configuration interaction calculations with excited state configurations. These have demonstrated the existence of a 2 P o excited state of e + Ca, which consists predominantly of a positronium cluster orbiting the Ca + ion in the L = 1 partial wave. Preliminary results are presented of excited state positron binding to a model alkali atom, where the excited 1 P o states are stable over a limited region. Implications for the unnatural parity, 2,4 S o , states of PsH, LiPs, NaPs and KPs are also discussed. The e + Mg, e + Cu, e + Zn and e + Cd systems show a lack of a 2 P o excited state, each instead possessing a low-energy p-wave shape resonance of varying strength.
12. Rated power factor and excitation system of large turbine generator
International Nuclear Information System (INIS)
Tokumitsu, Iwao; Watanabe, Takashi; Banjou, Minoru.
1979-01-01
As for the rated power factor of turbine generators for thermal power stations, 90% has been adopted since around 1960. On the other hand, power transmission system has entered 500 kV age, and 1,000 kV transmission is expected in the near future. As for the supply of reactive power from thermal and nuclear turbine generators, the necessity of supplying leading reactive power has rather increased. Now, the operating power factor of thermal and nuclear generators becomes 96 to 100% actually. As for the excess stability of turbine generators owing to the strengthening of transmission system and the adoption of super-high voltage, the demand of strict conditions can be dealt with by the adoption of super-fast response excitation system of thyristor shunt winding self exciting type. The adoption of the turbine generators with 90 to 95% power factor and the adoption of the thyristor shunt winding self exciting system were examined and evaluated. The rated power factor of generators, excitation system and economy of adopting these systems are explained. When the power factor of generators is increased from 0.9 to 0.95, about 6% of saving can be obtained in the installation cost. When the thyristor shunt winding self excitation is adopted, it is about 10% more economical than AC excitation. (Kako, I.)
13. Methodology to estimate parameters of an excitation system based on experimental conditions
Energy Technology Data Exchange (ETDEWEB)
Saavedra-Montes, A.J. [Carrera 80 No 65-223, Bloque M8 oficina 113, Escuela de Mecatronica, Universidad Nacional de Colombia, Medellin (Colombia); Calle 13 No 100-00, Escuela de Ingenieria Electrica y Electronica, Universidad del Valle, Cali, Valle (Colombia); Ramirez-Scarpetta, J.M. [Calle 13 No 100-00, Escuela de Ingenieria Electrica y Electronica, Universidad del Valle, Cali, Valle (Colombia); Malik, O.P. [2500 University Drive N.W., Electrical and Computer Engineering Department, University of Calgary, Calgary, Alberta (Canada)
2011-01-15
A methodology to estimate the parameters of a potential-source controlled rectifier excitation system model is presented in this paper. The proposed parameter estimation methodology is based on the characteristics of the excitation system. A comparison of two pseudo random binary signals, two sampling periods for each one, and three estimation algorithms is also presented. Simulation results from an excitation control system model and experimental results from an excitation system of a power laboratory setup are obtained. To apply the proposed methodology, the excitation system parameters are identified at two different levels of the generator saturation curve. The results show that it is possible to estimate the parameters of the standard model of an excitation system, recording two signals and the system operating in closed loop with the generator. The normalized sum of squared error obtained with experimental data is below 10%, and with simulation data is below 5%. (author)
14. Excitation power quantities in phase resonance testing of nonlinear systems with phase-locked-loop excitation
Science.gov (United States)
Peter, Simon; Leine, Remco I.
2017-11-01
Phase resonance testing is one method for the experimental extraction of nonlinear normal modes. This paper proposes a novel method for nonlinear phase resonance testing. Firstly, the issue of appropriate excitation is approached on the basis of excitation power considerations. Therefore, power quantities known from nonlinear systems theory in electrical engineering are transferred to nonlinear structural dynamics applications. A new power-based nonlinear mode indicator function is derived, which is generally applicable, reliable and easy to implement in experiments. Secondly, the tuning of the excitation phase is automated by the use of a Phase-Locked-Loop controller. This method provides a very user-friendly and fast way for obtaining the backbone curve. Furthermore, the method allows to exploit specific advantages of phase control such as the robustness for lightly damped systems and the stabilization of unstable branches of the frequency response. The reduced tuning time for the excitation makes the commonly used free-decay measurements for the extraction of backbone curves unnecessary. Instead, steady-state measurements for every point of the curve are obtained. In conjunction with the new mode indicator function, the correlation of every measured point with the associated nonlinear normal mode of the underlying conservative system can be evaluated. Moreover, it is shown that the analysis of the excitation power helps to locate sources of inaccuracies in the force appropriation process. The method is illustrated by a numerical example and its functionality in experiments is demonstrated on a benchmark beam structure.
15. Comparison of multiple support excitation solution techniques for piping systems
International Nuclear Information System (INIS)
Sterkel, H.P.; Leimbach, K.R.
1980-01-01
Design and analysis of nuclear power plant piping systems exposed to a variety of dynamic loads often require multiple support excitation analysis by modal or direct time integration methods. Both methods have recently been implemented in the computer program KWUROHR for static and dynamic analysis of piping systems, following the previous implementation of the multiple support excitation response spectrum method (see papers K 6/15 and K 6/15a of the SMiRT-4 Conference). The results of multiple support excitation response spectrum analyses can be examined by carrying out the equivalent time history analyses which do not distort the time phase relationship between the excitations at different support points. A frequent point of discussion is multiple versus single support excitation. A single support excitation analysis is computationally straightforward and tends to be on the conservative side, as the numerical results show. A multiple support excitation analysis, however, does not incur much more additional computer cost than the expenditure for an initial static solution involving three times the number, L, of excitation levels, i.e. 3L static load cases. The results are more realistic than those from a single support excitation analysis. A number of typical nuclear plant piping systems have been analyzed using single and multiple support excitation algorithms for: (1) the response spectrum method, (2) the modal time history method via the Wilson, Newmark and Goldberg integration operators and (3) the direct time history method via the Wilson integration operator. Characteristic results are presented to compare the computational quality of all three methods. (orig.)
16. Thermal Excitation System for Shearography (TESS)
Science.gov (United States)
Lansing, Matthew D.; Bullock, Michael W.
1996-01-01
One of the most convenient and effective methods of stressing a part or structure for shearographic evaluation is thermal excitation. This technique involves heating the part, often convectively with a heat gun, and then monitoring with a shearography device the deformation during cooling. For a composite specimen, unbonds, delaminations, inclusions, or matrix cracking will deform during cooling differently than other more structurally sound regions and thus will appear as anomalies in the deformation field. However, one of the difficulties that cause this inspection to be dependent on the operator experience is the conventional heating process. Fanning the part with a heat gun by hand introduces a wide range of variability from person to person and from one inspection to the next. The goal of this research effort was to conduct research in the methods of thermal excitation for shearography inspection. A computerized heating system was developed for inspection of 0.61 m (24 in.) square panels. The Thermal Excitation System for Shearography (TESS) provides radiant heating with continuous digital measurement of the surface temperature profile to ensure repeatability. The TESS device functions as an accessory to any electronic shearography device.
17. Excited, bound and resonant positron-atom systems
Energy Technology Data Exchange (ETDEWEB)
Bromley, M W J [Department of Physics and Computational Science Research Center, San Diego State University, San Diego CA 92182 (United States); Mitroy, J, E-mail: [email protected] [ARC Centre for Antimatter-Matter Studies and Faculty of Education, Health and Science, Charles Darwin University, Darwin NT 0909 (Australia)
2010-01-01
Calculations have demonstrated that eleven neutral atoms can bind positrons, while many more can bind positronium. This is a short review of recent progress made in understanding some of the underlying mechanisms. The emphasis here being on configuration interaction calculations with excited state configurations. These have demonstrated the existence of a {sup 2}P{sup o} excited state of e{sup +}Ca, which consists predominantly of a positronium cluster orbiting the Ca{sup +} ion in the L = 1 partial wave. Preliminary results are presented of excited state positron binding to a model alkali atom, where the excited {sup 1}P{sup o} states are stable over a limited region. Implications for the unnatural parity, {sup 2,4}S{sup o}, states of PsH, LiPs, NaPs and KPs are also discussed. The e{sup +}Mg, e{sup +}Cu, e{sup +}Zn and e{sup +}Cd systems show a lack of a {sup 2}P{sup o} excited state, each instead possessing a low-energy p-wave shape resonance of varying strength.
18. Modernization, reconstruction and development of excitation systems for synchronous generators
Directory of Open Access Journals (Sweden)
Arnautović Dušan
2011-01-01
Full Text Available This paper presents the previous results of work and development of excitation systems with digital automatic voltage regulators regarding their design, development, manufacturing and commissioning. A special attention was paid to the characteristics of excitation system voltage regulator.
19. Synchronization of chaos in non-identical parametrically excited systems
International Nuclear Information System (INIS)
Idowu, B.A.; Vincent, U.E.; Njah, A.N.
2009-01-01
In this paper, we investigate the synchronization of chaotic systems consisting of non-identical parametrically excited oscillators. The active control technique is employed to design control functions based on Lyapunov stability theory and Routh-Hurwitz criteria so as to achieve global chaos synchronization between a parametrically excited gyroscope and each of the parametrically excited pendulum and Duffing oscillator. Numerical simulations are implemented to verify the results.
20. Excitation of graphene plasmons as an analogy with the two-level system
International Nuclear Information System (INIS)
Fu, Jiahui; Lv, Bo; Li, Rujiang; Ma, Ruyu; Chen, Wan; Meng, Fanyi
2016-01-01
The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.
1. Excitation of graphene plasmons as an analogy with the two-level system
Energy Technology Data Exchange (ETDEWEB)
Fu, Jiahui [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Lv, Bo, E-mail: [email protected] [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Li, Rujiang [College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027 (China); Ma, Ruyu; Chen, Wan; Meng, Fanyi [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China)
2016-02-15
The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.
2. Nontrivial effects of high-frequency excitation for strongly damped mechanical systems
DEFF Research Database (Denmark)
Fidlin, Alexander; Thomsen, Jon Juel
Some nontrivial effects are investigated, which can occur if strongly damped mechanical systems are subjected to strong high-frequency (HF) excitation. The main result is a theoretical prediction, supported by numerical simulation, that for such systems the (quasi-)equilibrium states can change...... that can be substantial (depending on the strength of the HF excitation) for finite values of the damping. The analysis is focused on the differences between the classic results for weakly damped systems, and new effects for which the strong damping terms are responsible. The analysis is based...... on a slightly modified averaging technique, and includes an elementary example of an elliptically excited pendulum for illustration, alongside with a generalization to a broader class of strongly damped dynamical systems with HF excitation. As an application example, the nontrivial behavior of a classical...
3. Vibratory synchronization transmission of a cylindrical roller in a vibrating mechanical system excited by two exciters
Science.gov (United States)
Zhang, Xueliang; Wen, Bangchun; Zhao, Chunyu
2017-11-01
In present work vibratory synchronization transmission (VST) of a cylindrical roller with dry friction in a vibrating mechanical system excited by two exciters, is studied. Using the average method, the criterion of implementing synchronization of two exciters and that of ensuring VST of a roller, are achieved. The criterion of stability of the synchronous states satisfies the Routh-Hurwitz principle. The influences of the structural parameters of the system to synchronization and stability, are discussed numerically, which can be served as the theoretical foundation for engineering designs. An experiment is carried out, which approximately verify the validity of the theoretical and numerical results, as well as the feasibility of the method used. Utilizing the VST theory of a roller, some types of vibrating crushing or grinding equipments, etc., can be designed.
4. Nontrivial effects of high-frequency excitation for strongly damped mechanical systems
DEFF Research Database (Denmark)
Fidlin, Alexander; Thomsen, Jon Juel
2008-01-01
Some non-trivial effects are investigated, which can occur if strongly damped mechanical systems are subjected to strong high-frequency (HF) excitation. The main result is a theoretical prediction, supported by numerical simulation, that for such systems the (quasi-)equilibrium states can change...... that can be substantial depending on the strength of the HF excitation) for finite values of the damping. The analysis is focused on the differences between the classic results for weakly damped systems, and new effects for which the strong damping terms are responsible. The analysis is based on a slightly...... modified averaging technique, and includes an elementary example of an elliptically excited pendulum for illustration, alongside with a generalization to a broader class of strongly damped dynamical systems with HF excitation. As an application example, the nontrivial behavior of a classical optimally...
5. Encryption in Chaotic Systems with Sinusoidal Excitations
Directory of Open Access Journals (Sweden)
G. Obregón-Pulido
2014-01-01
Full Text Available In this contribution an encryption method using a chaotic oscillator, excited by “n” sinusoidal signals, is presented. The chaotic oscillator is excited by a sum of “n” sinusoidal signals and a message. The objective is to encrypt such a message using the chaotic behavior and transmit it, and, as the chaotic system is perturbed by the sinusoidal signal, the transmission security could be increased due to the effect of such a perturbation. The procedure is based on the regulation theory and consider that the receiver knows the frequencies of the perturbing signal, with this considerations the algorithm estimates the excitation in such a way that the receiver can cancel out the perturbation and all the undesirable dynamics in order to produce only the message. In this way we consider that the security level is increased.
6. Coherence resonance in an excitable system with time delay
International Nuclear Information System (INIS)
Sethia, Gautam C.; Kurths, Juergen; Sen, Abhijit
2007-01-01
We study the noise activated dynamics of a model excitable system that consists of a subcritical Hopf oscillator with a time delayed nonlinear feedback. The coherence of the noise driven pulses of the system exhibits a novel double peaked structure as a function of the noise amplitude. The two peaks correspond to separate optimal noise levels for excitation of single spikes and multiple spikes (bursts) respectively. The relative magnitudes of these peaks are found to be a sensitive function of time delay. The physical significance of our results and its practical implications in various real life systems are discussed
7. New formalism for determining excitation spectra of many-body systems
International Nuclear Information System (INIS)
Saito, S.; Zhang, S.B.; Louie, S.G.; Cohen, M.L.
1990-01-01
We present a new general formalism for determining the excitation spectrum of interacting many-body systems. The basic assumption is that the number of the excitations is equal to the number of sites. Within this approximation, it is shown that the density-density response functions with two different pure-imaginary energies determine the excitation spectrum. The method is applied to the valence electrons of sodium clusters of differing sizes in the time-dependent local-density approximation (TDLDA). A jellium-sphere background model is used for the ion cores. The excitation spectra obtained in this way represent well the excitation spectra given by the full TDLDA calculation along the real energy axis. Important collective modes are reproduced very well
8. Nuclear excited power generation system
International Nuclear Information System (INIS)
Parker, R.Z.; Cox, J.D.
1989-01-01
A power generation system is described, comprising: a gaseous core nuclear reactor; means for passing helium through the reactor, the helium being excited and forming alpha particles by high frequency radiation from the core of the gaseous core nuclear reactor; a reaction chamber; means for coupling chlorine and hydrogen to the reaction chamber, the helium and alpha particles energizing the chlorine and hydrogen to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for coupling the helium back to the gaseous core nuclear reactor; and means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, to be coupled back to the reaction chamber in a closed loop. The patent also describes a power generation system comprising: a gaseous core nuclear reactor; means for passing hydrogen through the reactor, the hydrogen being excited by high frequency radiation from the core; means for coupling chlorine to a reaction chamber, the hydrogen energizing the chlorine in the chamber to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, and means for coupling the hydrogen back to the gaseous core nuclear reactor in a closed loop
9. Picosecond excitation transport in disordered systems
International Nuclear Information System (INIS)
Hart, D.E.
1987-11-01
Time-resolved fluorescence decay profiles are used to study excitation transport in 2- and 3-dimensional disordered systems. Time-correlated single photon counting detection is used to collect the fluorescence depolarization data. The high signal-to-noise ratios afforded by this technique makes it possible to critically examine current theories of excitation transport. Care has been taken to eliminate or account for the experimental artifacts common to this type of study. Solutions of 3,3'-diethyloxadicarbocyanine iodide (DODCI) in glycerol serve as a radomly distributed array of energy donors in 3-dimensions. A very thin sample cell (/approximately/ 2 μm) is used to minimize the effects of fluorescence self-absorption on the decay kinetics. Evidence of a dynamic shift of the fluorescence spectrum of DODCI in glycerol due to solvent reorganization is presented. The effects of excitation trapping on the decay profiles is minimized in the data analysis procedure. The 3-body theory of Gochanour, Andersen, and Fayer (GAF) and the far less complex 2-particle analytic theory of Huber, Hamilton, and Barnett yield indistinguishable fits to the data over the wide dynamic range of concentrations and decay times studied
10. A portable tube exciting X-ray fluorescence analysis system
International Nuclear Information System (INIS)
Yang Qiang; Lai Wanchang; Ge Liangquan
2009-01-01
Article introduced a portable tube exciting X-ray fluorescence analysis system which is based on arm architecture. Also, we designed Tube control circuit and finished preliminary application. The energy and the intensity of the photon can be adjusted continuously by using the tube. Experiments show that high excitation efficiency obtained by setting the appropriate parameters of the tube for the various elements. (authors)
11. Excitation processes in organic systems under irradiation with vacuum ultraviolet radiation
International Nuclear Information System (INIS)
Shefer, Y.
1983-08-01
The subject of this work is the fluorescence of organic systems in the excitation range where phenomena of photon multiplication begin. It was hoped to reach the excitation energy above which the distribution of the various phenomena was constant and as a result, a linear function between the variation of the fluorescence intensity with variations of the excitation, would be obtained. The experimental set-up consisted mainly of suitable light sources, monochromators and detectors. The gated measuring system consisted of an oscilloscope, integrator and recorder. The material predominantly used in the experiments was anthracene whose absorption spectrum was investigated and calculated. The absorption spectra of various polycrystalline layers were also calculated. The absorption spectrum of a randomly ordered polycrystalline layer was compared with that of a hexane solution and a good correlation between the two spectra was obtained. For the study of the relationship between the excitation spectrum of anthracene and the order of crystal, the excitation spectrum of single crystals of anthracene was measured from 4 eV to 107 eV. For the excitation region from 10 eV to 23 eV the efficiency of exciting a singlet level by a photoelectron was calculated as a function of the kinetic energy of the photoelectron, assuming the efficiency of the recombination to be constant. The excitation spectra of single crystals of p-terphenyl, pyrene and phenanthrene were also examined. In all four crystals the excitation spectrum rises monotonically with an increase in the energy of the exciting photon. (author)
12. Design for the excitation systems of three generator sets of HL-2A
International Nuclear Information System (INIS)
Li Huajun; Xu Lirong; Liu Xuemei; You Tianxue
2001-01-01
The design for the excitation systems have been made on the basis of respective features and load demands of three motor-generator sets of HL-2A. The excitation systems of No.1 and No.2 generator sets which supply for toroidal field are discussed in detail and three feasible excitation plans have been proposed according to the investment
13. Dynamic performance estimation of stator voltage regulator in rotary exciter system with DC exciter
Directory of Open Access Journals (Sweden)
Stojić Đorđe
2011-01-01
Full Text Available In this paper, procedure for AVR parameter estimation is proposed, based on step responses when synchronous generator in idle run. The exciter system includes AVR, thyristor rectifier and DC exciter. AVR is realized in the form of cascade control structure with two control loops. PID controller in the outer loop represents the primary controller. P controller in the inner loop represents secondary controller which enables the faster field current response time. The aim of procedure is to determine equivalent gain of PID controller and thyristor rectifier. The measurements used in the parameter estimation procedure are taken from fossil power plant 'Kolubara A', aggregate A5.
14. Multiple excitation of supports - Part 2 : Implementation in TUBO system
International Nuclear Information System (INIS)
Galeao, A.C.N.R.; Barbosa, H.J.C.
1980-12-01
From the formulation of multiple excitation support problem, discussed in the first part of this work, and with the use of numerical techniques presented there, we discuss in this second part, the implementation in TUBO system, the follow procedure: Direct integration, Modal overlap, Spectral response emphasizing the aspects related to supports excitation. Finally, we present two numerical examples of TUBO system utilization in the solution of support movement problem. The several implemented computational procedures are compared. (E.G.) [pt
15. Bifurcation and chaos in neural excitable system
International Nuclear Information System (INIS)
Jing Zhujun; Yang Jianping; Feng Wei
2006-01-01
In this paper, we investigate the dynamical behaviors of neural excitable system without periodic external current (proposed by Chialvo [Generic excitable dynamics on a two-dimensional map. Chaos, Solitons and Fractals 1995;5(3-4):461-79] and with periodic external current as system's parameters vary. The existence and stability of three fixed points, bifurcation of fixed points, the conditions of existences of fold bifurcation, flip bifurcation and Hopf bifurcation are derived by using bifurcation theory and center manifold theorem. The chaotic existence in the sense of Marotto's definition of chaos is proved. We then give the numerical simulated results (using bifurcation diagrams, computations of Maximum Lyapunov exponent and phase portraits), which not only show the consistence with the analytic results but also display new and interesting dynamical behaviors, including the complete period-doubling and inverse period-doubling bifurcation, symmetry period-doubling bifurcations of period-3 orbit, simultaneous occurrence of two different routes (invariant cycle and period-doubling bifurcations) to chaos for a given bifurcation parameter, sudden disappearance of chaos at one critical point, a great abundance of period windows (period 2 to 10, 12, 19, 20 orbits, and so on) in transient chaotic regions with interior crises, strange chaotic attractors and strange non-chaotic attractor. In particular, the parameter k plays a important role in the system, which can leave the chaotic behavior or the quasi-periodic behavior to period-1 orbit as k varies, and it can be considered as an control strategy of chaos by adjusting the parameter k. Combining the existing results in [Generic excitable dynamics on a two-dimensional map. Chaos, Solitons and Fractals 1995;5(3-4):461-79] with the new results reported in this paper, a more complete description of the system is now obtained
16. Structural System Identification with Extended Kalman Filter and Orthogonal Decomposition of Excitation
Directory of Open Access Journals (Sweden)
Y. Ding
2014-01-01
Full Text Available Both the structural parameter and external excitation have coupling influence on structural response. A new system identification method in time domain is proposed to simultaneously evaluate structural parameter and external excitation. The method can be used for linear and hysteresis nonlinear structural condition assessment based on incomplete structural responses. In this method, the structural excitation is decomposed by orthogonal approximation. With this approximation, the strongly time-variant excitation identification is transformed to gentle time-variant, even constant parameters identification. Then the extended Kalman filter is applied to simultaneously identify state vector including the structural parameters and excitation orthogonal parameters in state space based on incomplete measurements. The proposed method is validated numerically with the simulation of three-story linear and nonlinear structures subject to external force. The external force on the top floor and the structural parameters are simultaneously identified with the proposed system identification method. Results from both simulations indicate that the proposed method is capable of identifing the dynamic load and structural parameters fairly accurately with contaminated incomplete measurement for both of the linear and nonlinear structural systems.
17. Identification of the low-energy excitations in a quantum critical system
Directory of Open Access Journals (Sweden)
Tom Heitmann
2017-05-01
Full Text Available We have identified low-energy magnetic excitations in a doped quantum critical system by means of polarized neutron scattering experiments. The presence of these excitations could explain why Ce(Fe0.76Ru0.242Ge2 displays dynamical scaling in the absence of local critical behavior or long-range spin-density wave criticality. The low-energy excitations are associated with the reorientations of the superspins of fully ordered, isolated magnetic clusters that form spontaneously upon lowering the temperature. The system houses both frozen clusters and dynamic clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401(R (2006].
18. Excitation model of pacemaker cardiomyocytes of cardiac conduction system
Science.gov (United States)
Grigoriev, M.; Babich, L.
2015-11-01
Myocardium includes typical and atypical cardiomyocytes - pacemakers, which form the cardiac conduction system. Excitation from the atrioventricular node in normal conditions is possible only in one direction. Retrograde direction of pulses is impossible. The most important prerequisite for the work of cardiomyocytes is the anatomical integrity of the conduction system. Changes in contractile force of the cardiomyocytes, which appear periodically, are due to two mechanisms of self-regulation - heterometric and homeometric. Graphic course of the excitation pulse propagation along the heart muscle more accurately reveals the understanding of the arrhythmia mechanism. These models have the ability to visualize the essence of excitation dynamics. However, they do not have the proper forecasting function for result estimation. Integrative mathematical model enables further investigation of general laws of the myocardium active behavior, allows for determination of the violation mechanism of electrical and contractile function of cardiomyocytes. Currently, there is no full understanding of the topography of pacemakers and ionic mechanisms. There is a need for the development of direction of mathematical modeling and comparative studies of the electrophysiological arrangement of cells of atrioventricular connection and ventricular conduction system.
19. Synchronization of Two Asymmetric Exciters in a Vibrating System
Directory of Open Access Journals (Sweden)
Zhaohui Ren
2011-01-01
Full Text Available We investigate synchronization of two asymmetric exciters in a vibrating system. Using the modified average method of small parameters, we deduce the non-dimensional coupling differential equations of the two exciters (NDDETE. By using the condition of existence for the zero solutions of the NDDETE, the condition of implementing synchronization is deduced: the torque of frequency capture is equal to or greater than the difference in the output electromagnetic torque between the two motors. Using the Routh-Hurwitz criterion, we deduce the condition of stability of synchronization that the inertia coupling matrix of the two exciters is positive definite. A numeric result shows that the structural parameters can meet the need of synchronization stability.
20. Development of the Fragment Molecular Orbital Method for Calculating Nonlocal Excitations in Large Molecular Systems.
Science.gov (United States)
Fujita, Takatoshi; Mochizuki, Yuji
2018-04-19
We developed the fragment-based method for calculating nonlocal excitations in large molecular systems. This method is based on the multilayer fragment molecular orbital method and the configuration interaction single (CIS) wave function using localized molecular orbitals. The excited-state wave function for the whole system is described as a superposition of configuration state functions (CSFs) for intrafragment excitations and for interfragment charge-transfer excitations. The formulation and calculations of singlet excited-state Hamiltonian matrix elements in the fragment CSFs are presented in detail. The efficient approximation schemes for calculating the matrix elements are also presented. The computational efficiency and the accuracy were evaluated using the molecular dimers and molecular aggregates. We confirmed that absolute errors of 50 meV (relative to the conventional calculations) are achievable for the molecular systems in their equilibrium geometries. The perturbative electron correlation correction to the CIS excitation energies is also demonstrated. The present theory can compute a large number of excited states in large molecular systems; in addition, it allows for the systematic derivation of a model exciton Hamiltonian. These features are useful for studying excited-state dynamics in condensed molecular systems based on the ab initio electronic structure theory.
1. Dynamic response of piping system subject to flow acoustic excitation
International Nuclear Information System (INIS)
Wang, T.; Sun, Y.S.
1988-01-01
Through the use of a theoretically derived and test data-calibrated forcing function, the dynamic response of a piping system subject to flow-acoustic induced vibration is analyzed. It is shown that the piping behavior can be predicted when consideration is given to both the wall flexural vibration and the piping system vibration. Piping responded as a system to the transversal excitation due to the swirling motion of the fluid flow, as well as flexurally to the high-frequency acoustic excitations. The transverse piping system response was calculated using a lumped mass piping model. The piping model has more stringent requirements than its counterpart for waterhammer and seismic modeling due to the shorter spiral wavelength and higher frequency of the forcing function. Proper modeling ensured that both the moment stress caused by system excitation and the local stress induced by the support reaction load were properly accounted for. Flexural vibration not only poses a threat to nipples and branch connections, but also contributes substantially to the resultant total stress experienced by the pipe. The forcing function approach has the advantage that the critical locations on the piping system can be identified by means of analysis, facilitating surveillance and inspection, as well as fatigue evaluation
2. Heat capacity for systems with excited-state quantum phase transitions
Energy Technology Data Exchange (ETDEWEB)
Cejnar, Pavel; Stránský, Pavel, E-mail: [email protected]
2017-03-18
Heat capacities of model systems with finite numbers of effective degrees of freedom are evaluated using canonical and microcanonical thermodynamics. Discrepancies between both approaches, which are observed even in the infinite-size limit, are particularly large in systems that exhibit an excited-state quantum phase transition. The corresponding irregularity of the spectrum generates a singularity in the microcanonical heat capacity and affects smoothly the canonical heat capacity. - Highlights: • Thermodynamics of systems with excited-state quantum phase transitions • ESQPT-generated singularities of the microcanonical heat capacity • Non-monotonous dependences of the canonical heat capacity • Discord between canonical and microcanonical pictures in the infinite-size limit.
3. The design of a sensor with flexible circuit excitation in electromagnetic tomography system
International Nuclear Information System (INIS)
Liu Ze; He Min; Xiong Hanliang
2005-01-01
A novel sensor structure of electromagnetic tomography system is presented in this paper. Flexible circuit straps are used in the excitation layer of the sensor and current of each strip can be controlled independently according to the excitation protocol matrix. In the sensor three kinds of excitation protocols: parallel, quasi-parallel and coil pair can be generated. Furthermore excitation field simulation and image reconstruction experiments have been done for analyzing the performance of the different excitation protocols
4. Stochastic stability of mechanical systems under renewal jump process parametric excitation
DEFF Research Database (Denmark)
Iwankiewicz, R.; Nielsen, Søren R.K.; Larsen, Jesper Winther
2005-01-01
A dynamic system under parametric excitation in the form of a non-Erlang renewal jump process is considered. The excitation is a random train of nonoverlapping rectangular pulses with equal, deterministic heights. The time intervals between two consecutive jumps up (or down), are the sum of two...
5. Excitation transfer in two two-level systems coupled to an oscillator
International Nuclear Information System (INIS)
Hagelstein, P L; Chaudhary, I U
2008-01-01
We consider a generalization of the spin-boson model in which two different two-level systems are coupled to an oscillator, under conditions where the oscillator energy is much less than the two-level system energies, and where the oscillator is highly excited. We find that the two-level system transition energy is shifted, producing a Bloch-Siegert shift in each two-level system similar to what would be obtained if the other were absent. At resonances associated with energy exchange between a two-level system and the oscillator, the level splitting is about the same as would be obtained in the spin-boson model at a Bloch-Siegert resonance. However, there occur resonances associated with the transfer of excitation between one two-level system and the other, an effect not present in the spin-boson model. We use a unitary transformation leading to a rotated system in which terms responsible for the shift and splittings can be identified. The level splittings at the anticrossings associated with both energy exchange and excitation transfer resonances are accounted for with simple two-state models and degenerate perturbation theory using operators that appear in the rotated Hamiltonian
6. Research on the reliability of friction system under combined additive and multiplicative random excitations
Science.gov (United States)
Sun, Jiaojiao; Xu, Wei; Lin, Zifei
2018-01-01
In this paper, the reliability of a non-linearly damped friction oscillator under combined additive and multiplicative Gaussian white noise excitations is investigated. The stochastic averaging method, which is usually applied to the research of smooth system, has been extended to the study of the reliability of non-smooth friction system. The results indicate that the reliability of friction system can be improved by Coulomb friction and reduced by random excitations. In particular, the effect of the external random excitation on the reliability is larger than the effect of the parametric random excitation. The validity of the analytical results is verified by the numerical results.
7. Distribution function of excitations in systems with fractional statistics
International Nuclear Information System (INIS)
Protogenov, A.P.
1992-08-01
The distribution function of low-energy excitations in 2+1D systems has been considered. It is shown that in these systems the quantum distribution function differs from the usual one by having a finite value of the entropy of linked braids. (author). 47 refs
8. Study on the adjustment capability of the excitation system located inside superconducting machine electromagnetic shield
Science.gov (United States)
Xia, D.; Xia, Z.
2017-12-01
The ability for the excitation system to adjust quickly plays a very important role in maintaining the normal operation of superconducting machines and power systems. However, the eddy currents in the electromagnetic shield of superconducting machines hinder the exciting magnetic field change and weaken the adjustment capability of the excitation system. To analyze this problem, a finite element calculation model for the transient electromagnetic field with moving parts is established. The effects of three different electromagnetic shields on the exciting magnetic field are analyzed using finite element method. The results show that the electromagnetic shield hinders the field changes significantly, the better its conductivity, the greater the effect on the superconducting machine excitation.
9. Relationships between resting conductances, excitability, and t-system ionic homeostasis in skeletal muscle.
Science.gov (United States)
Fraser, James A; Huang, Christopher L-H; Pedersen, Thomas H
2011-07-01
Activation of skeletal muscle fibers requires rapid sarcolemmal action potential (AP) conduction to ensure uniform excitation along the fiber length, as well as successful tubular excitation to initiate excitation-contraction coupling. In our companion paper in this issue, Pedersen et al. (2011. J. Gen. Physiol. doi:10.1085/jgp.201010510) quantify, for subthreshold stimuli, the influence upon both surface conduction velocity and tubular (t)-system excitation of the large changes in resting membrane conductance (G(M)) that occur during repetitive AP firing. The present work extends the analysis by developing a multi-compartment modification of the charge-difference model of Fraser and Huang to provide a quantitative description of the conduction velocity of actively propagated APs; the influence of voltage-gated ion channels within the t-system; the influence of t-system APs on ionic homeostasis within the t-system; the influence of t-system ion concentration changes on membrane potentials; and the influence of Phase I and Phase II G(M) changes on these relationships. Passive conduction properties of the novel model agreed with established linear circuit analysis and previous experimental results, while key simulations of AP firing were tested against focused experimental microelectrode measurements of membrane potential. This study thereby first quantified the effects of the t-system luminal resistance and voltage-gated Na(+) channel density on surface AP propagation and the resultant electrical response of the t-system. Second, it demonstrated the influence of G(M) changes during repetitive AP firing upon surface and t-system excitability. Third, it showed that significant K(+) accumulation occurs within the t-system during repetitive AP firing and produces a baseline depolarization of the surface membrane potential. Finally, it indicated that G(M) changes during repetitive AP firing significantly influence both t-system K(+) accumulation and its influence on the
10. Seismic response analysis of structural system subjected to multiple support excitation
International Nuclear Information System (INIS)
Wu, R.W.; Hussain, F.A.; Liu, L.K.
1978-01-01
In the seismic analysis of a multiply supported structural system subjected to nonuniform excitations at each support point, the single response spectrum, the time history, and the multiple response spectrum are the three commonly employed methods. In the present paper the three methods are developed, evaluated, and the limitations and advantages of each method assessed. A numerical example has been carried out for a typical piping system. Considerably smaller responses have been predicted by the time history method than that by the single response spectrum method. This is mainly due to the fact that the phase and amplitude relations between the support excitations are faithfully retained in the time history method. The multiple response spectrum prediction has been observed to compare favourably with the time history method prediction. Based on the present evaluation, the multiple response spectrum method is the most efficient method for seismic response analysis of structural systems subjected to multiple support excitation. (Auth.)
11. Chaos excited chaos synchronizations of integral and fractional order generalized van der Pol systems
International Nuclear Information System (INIS)
Ge Zhengming; Hsu Maoyuan
2008-01-01
In this paper, chaos excited chaos synchronizations of generalized van der Pol systems with integral and fractional order are studied. Synchronizations of two identified autonomous generalized van der Pol chaotic systems are obtained by replacing their corresponding exciting terms by the same function of chaotic states of a third nonautonomous or autonomous generalized van der Pol system. Numerical simulations, such as phase portraits, Poincare maps and state error plots are given. It is found that chaos excited chaos synchronizations exist for the fractional order systems with the total fractional order both less than and more than the number of the states of the integer order generalized van der Pol system
12. Adaptive Dynamic Surface Control for Generator Excitation Control System
Directory of Open Access Journals (Sweden)
Zhang Xiu-yu
2014-01-01
Full Text Available For the generator excitation control system which is equipped with static var compensator (SVC and unknown parameters, a novel adaptive dynamic surface control scheme is proposed based on neural network and tracking error transformed function with the following features: (1 the transformation of the excitation generator model to the linear systems is omitted; (2 the prespecified performance of the tracking error can be guaranteed by combining with the tracking error transformed function; (3 the computational burden is greatly reduced by estimating the norm of the weighted vector of neural network instead of the weighted vector itself; therefore, it is more suitable for the real time control; and (4 the explosion of complicity problem inherent in the backstepping control can be eliminated. It is proved that the new scheme can make the system semiglobally uniformly ultimately bounded. Simulation results show the effectiveness of this control scheme.
13. Analysis of piping system response to seismic excitations
International Nuclear Information System (INIS)
Wang, C.Y.
1987-01-01
This paper describes a numerical algorithm for analyzing piping system response to seismic excitations. The numerical model of the piping considers hoop, flexural, axial, and torsional modes of deformation. Hoop modes generated from internal hydrodynamic loading are superimposed on the bending and twisting modes by two extra degrees of freedom. A time-history analysis technique using the implicit temporal integration scheme is addressed. The time integrator uses a predictor-corrector successive iterative scheme which satisfies the equation of motion. Both geometrical and material nonlinearities are considered. Multiple support excitations, fluid effect, piping insulation, and material dampings can be included in the analysis. Two problems are presented to illustrate the method. The results are discussed in detail
14. Seismic analysis of piping systems subjected to multiple support excitations
International Nuclear Information System (INIS)
Sundararajan, C.; Vaish, A.K.; Slagis, G.C.
1981-01-01
The paper presents the results of a comparative study between the multiple response spectrum method and the time-history method for the seismic analysis of nuclear piping systems subjected to different excitation at different supports or support groups. First, the necessary equations for the above analysis procedures are derived. Then, three actual nuclear piping systems subjected to single and multiple excitations are analyzed by the different methods, and extensive comparisons of the results (stresses) are made. Based on the results, it is concluded that the multiple response spectrum analysis gives acceptable results as compared to the ''exact'', but much more costly, time-history analysis. 6 refs
15. Excitation functions of the systems 12C+14C and 13C+12C
International Nuclear Information System (INIS)
Haindl, E.
1975-01-01
The excitation functions of the systems 12 C+ 14 C and 13 C+ 12 C are investigated for different exit channels. The excitation functions measured do not show correlated structures as in the system 12 C+ 12 C. (WL/AK) [de
16. Spirals in a reaction-diffusion system: Dependence of wave dynamics on excitability
Science.gov (United States)
Mahanta, Dhriti; Das, Nirmali Prabha; Dutta, Sumana
2018-02-01
A detailed study of the effects of excitability of the Belousov-Zhabotinsky (BZ) reaction on spiral wave properties has been carried out. Using the Oregonator model, we explore the various regimes of wave activity, from sustained oscillations to wave damping, as the system undergoes a Hopf bifurcation, that is achieved by varying the excitability parameter, ɛ . We also discover a short range of parameter values where random oscillations are observed. With an increase in the value of ɛ , the frequency of the wave decreases exponentially, as the dimension of the spiral core expands. These numerical results are confirmed by carrying out experiments in thin layers of the BZ system, where the excitability is changed by varying the concentrations of the reactant species. Effect of reactant concentrations on wave properties like time period and wavelength are also explored in detail. Drifting and meandering spirals are found in the parameter space under investigation, with the excitability affecting the tip trajectory in a way predicted by the numerical studies. This study acts as a quantitative evidence of the relationship between the excitability parameter, ɛ , and the substrate concentrations.
17. Spirals in a reaction-diffusion system: Dependence of wave dynamics on excitability.
Science.gov (United States)
Mahanta, Dhriti; Das, Nirmali Prabha; Dutta, Sumana
2018-02-01
A detailed study of the effects of excitability of the Belousov-Zhabotinsky (BZ) reaction on spiral wave properties has been carried out. Using the Oregonator model, we explore the various regimes of wave activity, from sustained oscillations to wave damping, as the system undergoes a Hopf bifurcation, that is achieved by varying the excitability parameter, ε. We also discover a short range of parameter values where random oscillations are observed. With an increase in the value of ε, the frequency of the wave decreases exponentially, as the dimension of the spiral core expands. These numerical results are confirmed by carrying out experiments in thin layers of the BZ system, where the excitability is changed by varying the concentrations of the reactant species. Effect of reactant concentrations on wave properties like time period and wavelength are also explored in detail. Drifting and meandering spirals are found in the parameter space under investigation, with the excitability affecting the tip trajectory in a way predicted by the numerical studies. This study acts as a quantitative evidence of the relationship between the excitability parameter, ε, and the substrate concentrations.
18. Production of excited double hypernuclei via Fermi breakup of excited strange systems
International Nuclear Information System (INIS)
Sanchez Lorente, Alicia; Botvina, Alexander S.; Pochodzalla, Josef
2011-01-01
Precise spectroscopy of multi-strange hypernuclei provides a unique chance to explore the hyperon-hyperon interaction. In the present work we explore the production of excited states in double hypernuclei following the micro-canonical break-up of an initially excited double hypernucleus which is created by the absorption and conversion of a stopped Ξ - hyperon. Rather independent on the spectrum of possible excited states in the produced double hypernuclei the formation of excited states dominates in our model. For different initial target nuclei which absorb the Ξ - , different double hypernuclei nuclei dominate. Thus the ability to assign the various observable γ-transitions in a unique way to a specific double hypernuclei by exploring various light targets as proposed by the PANDA Collaboration seems possible. We also confront our predictions with the correlated pion spectra measured by the E906 Collaboration.
19. Experimental and theoretical evidence for fluctuation driven activations in an excitable chemical system
Science.gov (United States)
Hastings, Harold; Sobel, Sabrina; Field, Richard; Minchenberg, Scott; Spinelli, Nicole; Zauderer, Keith
2011-03-01
An excitable medium is a system in which small perturbations die out, but sufficiently large perturbations generate large ``excitations.'' Biological examples include neurons and the heart; the latter supports waves of excitation normally generated by the sinus node, but occasionally generated by other mechanisms. The ferroin-catalyzed Belousov-Zhabotinsky reaction is the prototype chemical excitable medium. We present experimental and theoretical evidence for that random fluctuations can generate excitations in the Belousov-Zhabothinsky reaction. Although the heart is significantly different, there are some scaling analogies. This material is based upon work supported by the Department of Energy under Award Number DE-FG02-08ER64623.
20. Excitation of electrostatic ion cyclotron wave in electron beam plasma system
International Nuclear Information System (INIS)
Fukumura, Takashi; Takamoto, Teruo
1984-01-01
The electrostatic ion cyclotron waves excited in an electron beam plasma system was investigated. The excitation condition of the waves was calculated by using Harris type dispersion relation under some assumption, and its comparison with the experimental result was made. Beam plasma discharge is a kind of RF discharge, and it is caused by the waves generated by the interaction of electron beam with plasma. It was shown that electrostatic ion cyclotron waves seemed to be the most probable as excited waves. But the excitation mechanism of these waves has not been concretely investigated. In this study, the excitation condition of electrostatic ion cyclotron waves was calculated as described above. The experimental apparatus and the results of potential, electric field and ion saturation current in beam plasma, electron drift motion in azimuthal direction and the waves excited in beam plasma are reported. The frequency of oscillation observed in beam plasma corresponds to the harmonics or subharmonics of ion cyclotron frequency. The calculation of Harris type dispersion relation, the numerical calculation and the comparison of the experimental result with the calculated result are described. (Kako, I.)
1. Modernization of the Control Systems of High-Frequency, Brush-Free, and Collector Exciters of Turbogenerators
Energy Technology Data Exchange (ETDEWEB)
Popov, E. N., E-mail: [email protected]; Komkov, A. L.; Ivanov, S. L.; Timoshchenko, K. P. [JSC “Scientific and Industrial Enterprise “Rusélprom-Élektromash” (Russian Federation)
2016-11-15
Methods of modernizing the regulation systems of electric machinery exciters with high-frequency, brush-free, and collector exciters by means of microprocessor technology are examined. The main problems of modernization are to increase the response speed of a system and to use a system stabilizer to increase the stability of the power system.
2. Spike Bursts from an Excitable Optical System
Science.gov (United States)
Rios Leite, Jose R.; Rosero, Edison J.; Barbosa, Wendson A. S.; Tredicce, Jorge R.
Diode Lasers with double optical feedback are shown to present power drop spikes with statistical distribution controllable by the ratio of the two feedback times. The average time between spikes and the variance within long time series are studied. The system is shown to be excitable and present bursting of spikes created with specific feedback time ratios and strength. A rate equation model, extending the Lang-Kobayashi single feedback for semiconductor lasers proves to match the experimental observations. Potential applications to construct network to mimic neural systems having controlled bursting properties in each unit will be discussed. Brazilian Agency CNPQ.
3. Base excitation testing system using spring elements to pivotally mount wind turbine blades
Science.gov (United States)
Cotrell, Jason; Hughes, Scott; Butterfield, Sandy; Lambert, Scott
2013-12-10
A system (1100) for fatigue testing wind turbine blades (1102) through forced or resonant excitation of the base (1104) of a blade (1102). The system (1100) includes a test stand (1112) and a restoring spring assembly (1120) mounted on the test stand (1112). The restoring spring assembly (1120) includes a primary spring element (1124) that extends outward from the test stand (1112) to a blade mounting plate (1130) configured to receive a base (1104) of blade (1102). During fatigue testing, a supported base (1104) of a blad (1102) may be pivotally mounted to the test stand (1112) via the restoring spring assembly (1120). The system (1100) may include an excitation input assembly (1140) that is interconnected with the blade mouting plate (1130) to selectively apply flapwise, edgewise, and/or pitch excitation forces. The restoring spring assemply (1120) may include at least one tuning spring member (1127) positioned adjacent to the primary spring element (1124) used to tune the spring constant or stiffness of the primary spring element (1124) in one of the excitation directions.
4. Exploring excited eigenstates of many-body systems using the functional renormalization group
Science.gov (United States)
Klöckner, Christian; Kennes, Dante Marvin; Karrasch, Christoph
2018-05-01
We introduce approximate, functional renormalization group based schemes to obtain correlation functions in pure excited eigenstates of large fermionic many-body systems at arbitrary energies. The algorithms are thoroughly benchmarked and their strengths and shortcomings are documented using a one-dimensional interacting tight-binding chain as a prototypical testbed. We study two "toy applications" from the world of Luttinger liquid physics: the survival of power laws in lowly excited states as well as the spectral function of high-energy "block" excitations, which feature several single-particle Fermi edges.
5. A study on an object transport system using ultrasonic wave excitation
International Nuclear Information System (INIS)
Jeong, Sang Hwa; Kim, Gwang Ho; Choi, Suk Bong; Park, Jun Ho; Cha, Kyoung Rae
2007-01-01
The development of information and telecommunication industries leads to the development of semiconductor and optical industries. In recent years, the demand of optical components is growing due to the demand of faster network. On the other hand, conventional transport systems are not adequate for transporting precision optical components and semiconductors. Because the conveyor belt can damage precision optical components with contact force and a magnetic system would destroy the inner structure of semiconductor with magnetic field, a new system for transporting optical components and semiconductors is required. One of the alternatives to the existing systems is a transport system using ultrasonic wave excitation since it can transport precision components such as semiconductors and optical components without damage. In this paper, a transport system using 2-mode ultrasonic wave excitation was developed for transporting optical components and semiconductor, and its performance was evaluated. The relationship between transporting characteristics and flexural beam shapes were evaluated
6. FSI analysis of piping systems under seismic excitation
International Nuclear Information System (INIS)
Uras, R.A.; Ma, D.C.; Chang, Yao W.; Liu, Wing Kam
1991-01-01
A formulation which accounts for fluid-structure interaction of piping system under seismic excitation is presented. The governing equations of the fluid and the structure to model the pipe are stated. Using the finite element method the discretized equations are obtained. A transformation procedure for proper assembly of matrices is introduced. A solution algorithm is described. 9 refs., 2 figs
7. The conditions for attaining the greatest degree of system stability with strict generator excitation control
Energy Technology Data Exchange (ETDEWEB)
Gruzdev, I.A.; Ekimova, M.M.; Truspekova, G.A.
1982-01-01
Expressions are derived for an idealized model of a complex electric power system; these expressions define the greatest level of stability of an electric power system and the optimum combination of stabilization factors with automatic excitation control in a single power system. The possibility of increasing the level of stability of an electric power system with simultaneous strict automatic excitation control of the synychronous generators in several power systems is analyzed.
8. Non-linear operation of nanomechnical systems combining photothermal excitation and magneto-motive detection
International Nuclear Information System (INIS)
Koenig, Daniel R; Metzger, Constanze; Camerer, Stephan; Kotthaus, Joerg P
2006-01-01
We present a non-linear operation of a nanomechanical beam resonator by photothermal excitation at 4 K. The resonators dimensions are 10 μm in length, 200 nm in width, and 200 nm in height. The actuation mechanism is based on a pulsed diode laser focused onto the centre of the beam resonator. Thermally induced stress caused by the different thermal expansion coefficients of the bi-layer system periodically deflects the resonator. Magnetomotively detected amplitudes up to 150 nm are reached at the fundamental resonance mode at a frequency of 8.9 MHz. Furthermore, the third eigenmode of the resonator at a frequency 36 MHz is also excited. We conclude that the photothermal excitation at 4 K should be applicable up to the GHz regime, the operation in the non-linear regime can be used for performance enhancement of nanomechanical systems, and the combination of photothermal excitation and magneto-motive detection avoids undesired cross talk
9. The excitation system of 727.5 MVA synchronous generator of the unit B1 in TPP 'Nikola Tesla B'
Directory of Open Access Journals (Sweden)
Ćirić Zoran
2013-01-01
Full Text Available This paper presents a technical solution for the replacement of the excitation system of the unit B1 in TPP 'Nikola Tesla B' as a part of the maintenance service in 2012. Since the generators of TPP 'Nikola Tesla B' have the greatest power in the power system of Serbia, it was necessary to achieve high reliability of the excitation system so that the process of producing electricity is not endangered Considering this, the implemented excitation system uses modern technology with redundancy both in the power and control blocks, which resulted in an increase in the hot reserve by 100%. In addition, it was necessary to adjust the excitation system to increased generator power and performance from 618MW to 667.5MW. In this paper, the main parameters of the excitation system are given: the power, the excitation system control, the thyristor ignition system, the event recorder system, the digital relay protection, as well as the measuring and signaling functions.
10. Control of base-excited dynamical systems through piezoelectric energy harvesting absorber
Science.gov (United States)
Abdelmoula, H.; Dai, H. L.; Abdelkefi, A.; Wang, L.
2017-09-01
The spring-mass absorber usually offers a good control to dynamical systems under direct base excitations for a specific value of the excitation frequency. As the vibrational energy of a primary dynamical system is transferred to the absorber, it gets dissipated. In this study, this energy is no longer dissipated but converted to available electrical power by designing efficient energy harvesters. A novel design of a piezoelectric beam installed inside an elastically-mounted dynamical system undergoing base excitations is considered. A design is carried out in order to determine the properties and dimensions of the energy harvester with the constraint of simultaneously decreasing the oscillating amplitudes of the primary dynamical system and increasing the harvested power of the energy harvesting absorber. An analytical model for the coupled system is constructed using Euler-Lagrange principle and Galerkin discretization. Different strategies for controlling the primary structure displacement and enhancing the harvested power as functions of the electrical load resistance and thickness of the beam substrate are performed. The linear polynomial approximation of the system’s key parameters as a function of the beam’s substrate thickness is first carried out. Then, the gradient method is applied to determine the adequate values of the electrical load resistance and thickness of the substrate under the constraints of minimizing the amplitudes of the primary structure or maximizing the levels of the harvested power. After that, an iterative strategy is considered in order to simultaneously minimize the amplitudes of the primary structure and maximize the levels of the harvested power as functions of the thickness of the substrate and electrical load resistance. In addition to harmonic excitations, the coupled system subjected to a white noise is explored. Through this analysis, the load resistance and thickness of the substrate of the piezoelectric energy harvester
11. Vibrational-rotational excitation: chemical reactions of vibrationally excited molecules
International Nuclear Information System (INIS)
Moore, C.B.; Smith, I.W.M.
1979-03-01
This review considers a limited number of systems, particularly gas-phase processes. Excited states and their preparation, direct bimolecular reactions, reactions of highly excited molecules, and reactions in condensed phases are discussed. Laser-induced isotope separation applications are mentioned briefly. 109 references
12. Optimization of tube parameters in a tube excited X-ray fluorescence (TEXRF) system using secondary fluorescers
International Nuclear Information System (INIS)
Islam, A.; Biswas, S.K.
1995-12-01
A study of the optimization of excitation parameters in a tube excited X-ray fluorescence system (TEXRF) having Mo as the primary target has been carried out for biological matrix. Fe, Zn and Mo were used as the secondary fluorecers. For the present investigation a cellulose based synthetic standard containing K, Cr, Ni, Zn, Se and Y was excited with the TEXRF system. All experiments were carried out under the same experimental conditions except the tube potential. For each fluorescer the minimum detection limits (MDL) of excited elements were calculated for the corresponding tube voltage. The MDLs were found to be increasing with decreasing atomic number and it was also observed that the maximum sensitivity with Fe and Zn secondary fluorescers for elements analyzed occurred around 35 kV of the excitation potential. For Mo secondary fluorescer maximum sensitivity was found at higher excitation potential. In most cases MDLs were minimum at 40-45 kV of the excitation potential. 5 refs., 12 figs
13. Using axicons for depth discrimination in excitation-emission laser scanning imaging systems
Science.gov (United States)
Iglesias, Ignacio
2017-10-01
Besides generating good approximations to zero-order Bessel beams, an axicon lens coupled to a spatial filter can be used to collect light while preserving information on the depth coordinate of the source location. To demonstrate the principle, we describe an experimental excitation-emission fluorescence imaging system that uses an axicon twice: to generate an excitation Bessel beam and to collect the emitted light.
14. Applicability of annular-source excited systems in quantitative XRF analysis
International Nuclear Information System (INIS)
Mahmoud, A.; Bernasconi, G.; Bamford, S.A.; Dosan, B.; Haselberger, N.; Markowicz, A.
1996-01-01
Radioisotope-excited XRF systems, using annular sources, are widely used in view of their simplicity, wide availability, relatively low price for the complete system and good overall performance with respect to accuracy and detection limits. However some problems arise when the use of fundamental parameter techniques for quantitative analysis is attempted. These problems are due to the fact that the systems operate with large solid angles for incoming and emerging radiation and both the incident and take-off angles are not trivial. In this paper an improved way to calculate effective values for the incident and take-off angles, using monte Carlo (M C) integration techniques is shown. In addition, a study of the applicability of the effective angles for analysing different samples, or standards was carried out. The M C method allows also calculation of the excitation-detection efficiency for different parts of the sample and estimation of the overall efficiency of a source-excited XRF setup. The former information is useful in the design of optimized XRF set-ups and prediction of the response of inhomogeneous samples. A study of the sensitivity of the results due to sample characteristics and a comparison of the results with experimentally determined values for incident and take-off angles is also presented. A flexible and user-friendly computer program was developed in order to perform efficiently the lengthy calculation involved. (author). 14 refs. 5 figs
15. Multi-frequency excitation
KAUST Repository
2016-03-10
Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.
16. The Modeling and Analysis for the Self-Excited Vibration of the Maglev Vehicle-Bridge Interaction System
Directory of Open Access Journals (Sweden)
Jinhui Li
2015-01-01
Full Text Available This paper addresses the self-excited vibration problems of maglev vehicle-bridge interaction system which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, two levitation models with different complexity are developed, and the comparison of the energy curves associated with the two models is carried out. We conclude that the interaction model with a single levitation control unit is sufficient for the study of the self-excited vibration. Then, the principle underlying the self-excited vibration is explored from the standpoint of work acting on the bridge done by the levitation system. Furthermore, the influences of the parameters, including the modal frequency and modal damping of bridge, the gain of the controller, the sprung mass, and the unsprung mass, on the stability of the interaction system are carried out. The study provides a theoretical guidance for solving the self-excited vibration problems of the vehicle-bridge interaction systems.
17. H∞ Excitation Control Design for Stochastic Power Systems with Input Delay Based on Nonlinear Hamiltonian System Theory
Directory of Open Access Journals (Sweden)
Weiwei Sun
2015-01-01
Full Text Available This paper presents H∞ excitation control design problem for power systems with input time delay and disturbances by using nonlinear Hamiltonian system theory. The impact of time delays introduced by remote signal transmission and processing in wide-area measurement system (WAMS is well considered. Meanwhile, the systems under investigation are disturbed by random fluctuation. First, under prefeedback technique, the power systems are described as a nonlinear Hamiltonian system. Then the H∞ excitation controller of generators connected to distant power systems with time delay and stochasticity is designed. Based on Lyapunov functional method, some sufficient conditions are proposed to guarantee the rationality and validity of the proposed control law. The closed-loop systems under the control law are asymptotically stable in mean square independent of the time delay. And we through a simulation of a two-machine power system prove the effectiveness of the results proposed in this paper.
18. Design, fabrication and testing of a 5-Hz acoustic exciter system
Science.gov (United States)
Lundy, D. H.; Robinson, G. D.
1973-01-01
A 5-Hz acoustic excitation system was designed, fabricated and checked out for use in the modulation of a stagnant gas volume contained in an absorption cell. A detailed system description of the test equipment, both mechanical and electronic, and an operating procedure are included. Conclusions are also presented.
19. Fragment emission from modestly excited nuclear systems
Energy Technology Data Exchange (ETDEWEB)
Lou, Y. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Souza, R.T. de [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Chen, S.L. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Cornell, E.W. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Davin, B. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Fox, D. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Hamilton, T.M. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Mcdonald, K. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility; Tsang, M.B. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Glasmacher, T. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Dinius, J. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Gelbke, C.K. [Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Handzy, D.O. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry]|[Indiana Univ., Bloomington, IN (United States). Cyclotron Facility]|[Michigan State Univ., East Lansing, MI (United States). National Superconducting Cyclotron Lab.; Hsi, W.C.
1996-07-08
Fragment emission patterns occurring in nuclear systems of modest excitation are studied. Exclusive measurement of fragment emission in {sup 14}N+{sup 197}Au reactions at E/A=100, 130 and 156 MeV allows selection of central collisions where a single source dominates the decay. Low threshold measurement of IMF emission for these events allows investigation of the influence of detector threshold effects. The time scale of fragment emission is deduced using fragment-fragment velocity correlations. Comparisons are made to the predictions of a statistical decay model. (orig.).
20. Beam excitation and damping with the transverse feedback system
International Nuclear Information System (INIS)
Pellegrin, J.L.; Rees, J.R.
1979-08-01
The questions often come up, ''What is the strength if the beam excitation system? How much damping can the transverse feedback provide?'' The design is now advanced enough to answer these questions; also, laboratory tests of some components have been conducted and we know what can be expected of the hardware. This paper discusses these questions
1. Indirect control of quantum systems via an accessor: pure coherent control without system excitation
International Nuclear Information System (INIS)
Fu, H C; Dong Hui; Sun, C P; Liu, X F
2009-01-01
A pure indirect control of quantum systems via a quantum accessor is investigated. In this control scheme, we do not apply any external classical excitation fields on the controlled system and we control a quantum system via a quantum accessor and classical control fields control the accessor only. Complete controllability is investigated for arbitrary finite-dimensional quantum systems and exemplified by two- and three-dimensional systems. The scheme exhibits some advantages; it uses less qubits in the accessor and does not depend on the energy-level structure of the controlled system
2. Pure-Phase Selective Excitation in Fast-Relaxing Systems
Science.gov (United States)
Zangger, Klaus; Oberer, Monika; Sterk, Heinz
2001-09-01
Selective pulses have been used frequently for small molecules. However, their application to proteins and other macromolecules has been limited. The long duration of shaped-selective pulses and the short T2 relaxation times in proteins often prohibited the use of highly selective pulses especially on larger biomolecules. A very selective excitation can be obtained within a short time by using the selective excitation sequence presented in this paper. Instead of using a shaped low-intensity radiofrequency pulse, a cluster of hard 90° pulses, delays of free precession, and pulsed field gradients can be used to selectively excite a narrow chemical shift range within a relatively short time. Thereby, off-resonance magnetization, which is allowed to evolve freely during the free precession intervals, is destroyed by the gradient pulses. Off-resonance excitation artifacts can be removed by random variation of the interpulse delays. This leads to an excitation profile with selectivity as well as phase and relaxation behavior superior to that of commonly used shaped-selective pulses. Since the evolution of scalar coupling is inherently suppressed during the double-selective excitation of two different scalar-coupled nuclei, the presented pulse cluster is especially suited for simultaneous highly selective excitation of N-H and C-H fragments. Experimental examples are demonstrated on hen egg white lysozyme (14 kD) and the bacterial antidote ParD (19 kD).
3. Application of Excitation from Multiple Locations on a Simplified High-Lift System
Science.gov (United States)
Melton, LaTunia Pack; Yao, Chung-Sheng; Seifert, Avi
2004-01-01
A series of active flow control experiments were recently conducted on a simplified high-lift system. The purpose of the experiments was to explore the prospects of eliminating all but simply hinged leading and trailing edge flaps, while controlling separation on the supercritical airfoil using multiple periodic excitation slots. Excitation was provided by three. independently controlled, self-contained, piezoelectric actuators. Low frequency excitation was generated through amplitude modulation of the high frequency carrier wave, the actuators' resonant frequencies. It was demonstrated, for the first time, that pulsed modulated signal from two neighboring slots interact favorably to increase lift. Phase sensitivity at the low frequency was measured, even though the excitation was synthesized from the high-frequency carrier wave. The measurements were performed at low Reynolds numbers and included mean and unsteady surface pressures, surface hot-films, wake pressures and particle image velocimetry. A modest (6%) increase in maximum lift (compared to the optimal baseline) was obtained due t o the activation of two of the three actuators.
4. Line shape of magnetic excitations in singlet-ground-state systems
International Nuclear Information System (INIS)
Bak, P.
1976-08-01
The excitation spectrum in a paramagnetic singlet doublet system is calculated using a diagrammatic expansion technique, and the theoretical predictions are compared with experiments on praseodymium. The theory gives an accurate description of the dramatic temperature dependence of the energies and lineshapes for the exciton modes
5. Excited State Structural Dynamics of Carotenoids and Charge Transfer Systems
International Nuclear Information System (INIS)
Van Tassle, Aaron Justin
2006-01-01
This dissertation describes the development and implementation of a visible/near infrared pump/mid-infrared probe apparatus. Chapter 1 describes the background and motivation of investigating optically induced structural dynamics, paying specific attention to solvation and the excitation selection rules of highly symmetric molecules such as carotenoids. Chapter 2 describes the development and construction of the experimental apparatus used throughout the remainder of this dissertation. Chapter 3 will discuss the investigation of DCM, a laser dye with a fluorescence signal resulting from a charge transfer state. By studying the dynamics of DCM and of its methyl deuterated isotopomer (an otherwise identical molecule), we are able to investigate the origins of the charge transfer state and provide evidence that it is of the controversial twisted intramolecular (TICT) type. Chapter 4 introduces the use of two-photon excitation to the S1 state, combined with one-photon excitation to the S2 state of the carotenoid beta-apo-8'-carotenal. These 2 investigations show evidence for the formation of solitons, previously unobserved in molecular systems and found only in conducting polymers Chapter 5 presents an investigation of the excited state dynamics of peridinin, the carotenoid responsible for the light harvesting of dinoflagellates. This investigation allows for a more detailed understanding of the importance of structural dynamics of carotenoids in light harvesting
6. Response analysis of a class of quasi-linear systems with fractional derivative excited by Poisson white noise
Science.gov (United States)
Yang, Yongge; Xu, Wei; Yang, Guidong; Jia, Wantao
2016-08-01
The Poisson white noise, as a typical non-Gaussian excitation, has attracted much attention recently. However, little work was referred to the study of stochastic systems with fractional derivative under Poisson white noise excitation. This paper investigates the stationary response of a class of quasi-linear systems with fractional derivative excited by Poisson white noise. The equivalent stochastic system of the original stochastic system is obtained. Then, approximate stationary solutions are obtained with the help of the perturbation method. Finally, two typical examples are discussed in detail to demonstrate the effectiveness of the proposed method. The analysis also shows that the fractional order and the fractional coefficient significantly affect the responses of the stochastic systems with fractional derivative.
7. Response analysis of a class of quasi-linear systems with fractional derivative excited by Poisson white noise
International Nuclear Information System (INIS)
Yang, Yongge; Xu, Wei; Yang, Guidong; Jia, Wantao
2016-01-01
The Poisson white noise, as a typical non-Gaussian excitation, has attracted much attention recently. However, little work was referred to the study of stochastic systems with fractional derivative under Poisson white noise excitation. This paper investigates the stationary response of a class of quasi-linear systems with fractional derivative excited by Poisson white noise. The equivalent stochastic system of the original stochastic system is obtained. Then, approximate stationary solutions are obtained with the help of the perturbation method. Finally, two typical examples are discussed in detail to demonstrate the effectiveness of the proposed method. The analysis also shows that the fractional order and the fractional coefficient significantly affect the responses of the stochastic systems with fractional derivative.
8. Response analysis of a class of quasi-linear systems with fractional derivative excited by Poisson white noise
Energy Technology Data Exchange (ETDEWEB)
Yang, Yongge; Xu, Wei, E-mail: [email protected]; Yang, Guidong; Jia, Wantao [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)
2016-08-15
The Poisson white noise, as a typical non-Gaussian excitation, has attracted much attention recently. However, little work was referred to the study of stochastic systems with fractional derivative under Poisson white noise excitation. This paper investigates the stationary response of a class of quasi-linear systems with fractional derivative excited by Poisson white noise. The equivalent stochastic system of the original stochastic system is obtained. Then, approximate stationary solutions are obtained with the help of the perturbation method. Finally, two typical examples are discussed in detail to demonstrate the effectiveness of the proposed method. The analysis also shows that the fractional order and the fractional coefficient significantly affect the responses of the stochastic systems with fractional derivative.
9. Localized excitations in nonlinear complex systems current state of the art and future perspectives
CERN Document Server
Cuevas-Maraver, Jesús; Frantzeskakis, Dimitri; Karachalios, Nikos; Kevrekidis, Panayotis; Palmero-Acebedo, Faustino
2014-01-01
The study of nonlinear localized excitations is a long-standing challenge for research in basic and applied science, as well as engineering, due to their importance in understanding and predicting phenomena arising in nonlinear and complex systems, but also due to their potential for the development and design of novel applications. This volume is a compilation of chapters representing the current state-of-the-art on the field of localized excitations and their role in the dynamics of complex physical systems.
10. Study of resonant magnet exciting system for the 3 GeV proton synchrotron
Energy Technology Data Exchange (ETDEWEB)
Koseki, Shoichiro; Zhang, Fengqing; Watanabe, Yasuhiro; Tani, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Adachi, Toshikazu; Someya, Hirohiko [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)
2001-07-01
Exciting system for magnets of the 3 GeV Proton synchrotron is under consideration. A resonant exciting system is studied, and two type of power supply are compared. One is a parallel supply that is used generally. Another is a modified series supply. Either of them uses IGBT sinusoidal converters. Capacity of the power converter of the series supply for bending magnets becomes 28.8 MVAp. This is lager more than twice compared with the parallel supply. In the other hand, the series supply has good control performance and flexibility. More study is necessary to decide finally. (author)
11. Assessment of time-dependent density functional theory with the restricted excitation space approximation for excited state calculations of large systems
Science.gov (United States)
Hanson-Heine, Magnus W. D.; George, Michael W.; Besley, Nicholas A.
2018-06-01
The restricted excitation subspace approximation is explored as a basis to reduce the memory storage required in linear response time-dependent density functional theory (TDDFT) calculations within the Tamm-Dancoff approximation. It is shown that excluding the core orbitals and up to 70% of the virtual orbitals in the construction of the excitation subspace does not result in significant changes in computed UV/vis spectra for large molecules. The reduced size of the excitation subspace greatly reduces the size of the subspace vectors that need to be stored when using the Davidson procedure to determine the eigenvalues of the TDDFT equations. Furthermore, additional screening of the two-electron integrals in combination with a reduction in the size of the numerical integration grid used in the TDDFT calculation leads to significant computational savings. The use of these approximations represents a simple approach to extend TDDFT to the study of large systems and make the calculations increasingly tractable using modest computing resources.
12. Stand-alone front-end system for high- frequency, high-frame-rate coded excitation ultrasonic imaging.
Science.gov (United States)
Park, Jinhyoung; Hu, Changhong; Shung, K Kirk
2011-12-01
A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 V(pp). The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO(3)) single-element lightweight (<;0.28 g) transducers were utilized. The wire target measure- ment showed that the -6-dB axial resolution of a chirp-coded excitation was 50 μm and lateral resolution was 120 μm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation.
13. Formation of excited states in high-Z helium-like systems
International Nuclear Information System (INIS)
Fritzsche, S.; Fricke, B.; Brinzanescu, O.
1999-12-01
High-Z helium-like ions represent the simplest multi-electron systems for studying the interplay between electron-electron correlations, relativistic as well as quantum electrodynamical effects in strong fields. In contrast to the adjacent lithium-like ions, however, almost no experimental information is available about the excited states in the high-Z domain of the helium sequence. Here, we present a theoretical analysis of the X-ray production and decay dynamics of the excited states in helium-like uranium. Emphasize has been paid particularly to the formation of the 3 P 0 and 3 P 2 levels by using electron capture into hydrogen-like U 91+ . Both states are of interest for precise measurements on high-Z helium-like ions in the future. (orig.)
14. Excitations in superfluid systems: contributions of the nuclear structure; Excitations dans les systemes superfluides: contributions de la structure nucleaire
Energy Technology Data Exchange (ETDEWEB)
Khan, E
2005-12-15
The author presents successively the theoretical aspect, the experimental aspect and the applied aspect of excitations in nuclear structures. The quasi-particle random phase approximation (QRPA) tool is first described. Recent approaches on QRPA are based on the theory of the density function where the ground state and excited states are described from the same nucleon-nucleon interaction. 2 methods for measuring the collective excitations are then presented: the proton scattering that has the potentiality to investigate the evolution of magicity, the second method is in fact a new method for measuring the giant mono-polar resonance (GMP) in exotic nuclei. Nuclear reactions are considered as a compulsory step on the way from observables like cross-sections to nuclear structure. The author highlights the assets of the convolution model that can generate the optical potential from the effective nucleon-nucleon interaction and from proton and neutron densities of the nuclei involved. R-processes in nucleosynthesis and neutron stars are reviewed as applications of collective excitations in the field of nuclear astrophysics. (A.C.)
15. Studies of isotopic effects in the excited electronic states of molecular systems
International Nuclear Information System (INIS)
1982-01-01
Rare gas halogen (RGH) lasers serve as convenient tools for a range of photophysical processes which exhibit isotope effects. This document summarizes progress in the production of molecular systems in their electronic excited states with the aid of RGH lasers, and the various isotopic effects one can study under these conditions. We conclude that the basic physical mechanisms involved in the isotopically sensitive characteristics of excited molecular electronic states are sufficiently selective to be useful in both the detection and separation of many atomic materials
16. A High-Voltage SOI CMOS Exciter Chip for a Programmable Fluidic Processor System.
Science.gov (United States)
Current, K W; Yuk, K; McConaghy, C; Gascoyne, P R C; Schwartz, J A; Vykoukal, J V; Andrews, C
2007-06-01
A high-voltage (HV) integrated circuit has been demonstrated to transport fluidic droplet samples on programmable paths across the array of driving electrodes on its hydrophobically coated surface. This exciter chip is the engine for dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip systems, creating field excitations that inject and move fluidic droplets onto and about the manipulation surface. The architecture of this chip is expandable to arrays of N X N identical HV electrode driver circuits and electrodes. The exciter chip is programmable in several senses. The routes of multiple droplets may be set arbitrarily within the bounds of the electrode array. The electrode excitation waveform voltage amplitude, phase, and frequency may be adjusted based on the system configuration and the signal required to manipulate a particular fluid droplet composition. The voltage amplitude of the electrode excitation waveform can be set from the minimum logic level up to the maximum limit of the breakdown voltage of the fabrication technology. The frequency of the electrode excitation waveform can also be set independently of its voltage, up to a maximum depending upon the type of droplets that must be driven. The exciter chip can be coated and its oxide surface used as the droplet manipulation surface or it can be used with a top-mounted, enclosed fluidic chamber consisting of a variety of materials. The HV capability of the exciter chip allows the generated DEP forces to penetrate into the enclosed chamber region and an adjustable voltage amplitude can accommodate a variety of chamber floor thicknesses. This demonstration exciter chip has a 32 x 32 array of nominally 100 V electrode drivers that are individually programmable at each time point in the procedure to either of two phases: 0deg and 180deg with respect to the reference clock. For this demonstration chip, while operating the electrodes with a 100-V peak-to-peak periodic waveform, the maximum HV electrode
17. An optical authentication system based on imaging of excitation-selected lanthanide luminescence.
Science.gov (United States)
Carro-Temboury, Miguel R; Arppe, Riikka; Vosch, Tom; Sørensen, Thomas Just
2018-01-01
Secure data encryption relies heavily on one-way functions, and copy protection relies on features that are difficult to reproduce. We present an optical authentication system based on lanthanide luminescence from physical one-way functions or physical unclonable functions (PUFs). They cannot be reproduced and thus enable unbreakable encryption. Further, PUFs will prevent counterfeiting if tags with unique PUFs are grafted onto products. We have developed an authentication system that comprises a hardware reader, image analysis, and authentication software and physical keys that we demonstrate as an anticounterfeiting system. The physical keys are PUFs made from random patterns of taggants in polymer films on glass that can be imaged following selected excitation of particular lanthanide(III) ions doped into the individual taggants. This form of excitation-selected imaging ensures that by using at least two lanthanide(III) ion dopants, the random patterns cannot be copied, because the excitation selection will fail when using any other emitter. With the developed reader and software, the random patterns are read and digitized, which allows a digital pattern to be stored. This digital pattern or digital key can be used to authenticate the physical key in anticounterfeiting or to encrypt any message. The PUF key was produced with a staggering nominal encoding capacity of 7 3600 . Although the encoding capacity of the realized authentication system reduces to 6 × 10 104 , it is more than sufficient to completely preclude counterfeiting of products.
18. Excited species in the FBX dosimeter system
International Nuclear Information System (INIS)
Gupta, B.L.
2003-01-01
In the FBX dosimeter solution, the excitation of xylenol orange (XO) produces maximum emission at 550-575 nm both at room and liquid nitrogen temperatures (about 85%) having a lifetime of 0.20-0.36 ns. In addition, at room temperature there is an emission at 350 nm for the excitation at 260 nm (about 15%) having a longer lifetime of 3.71-4.01 ns. Benzoic acid (BA) has excitation at 284-295 nm and emission at 320-365 nm having a lifetime of 1.38 ns. In an aqueous solution containing 5x10 -3 mol dm -3 BA, 2x10 -4 mol dm -3 XO and 0.04 mol dm -3 H 2 SO 4 there is no XO emission at 550 nm due to UV absorption at 260 nm by BA. In this solution, 2 emissions are observed near 350-360 nm, having lifetimes of 1.25 ns (89%) and 2.86 ns (11%). The wavelengths for the emission of XO and absorption of ferric-XO complex are nearly the same. Excited XO produces oxidation of ferrous ions and BA increases the chain length
19. A new autogenous mobile system driven by vibration without impacts, excited by an impulse periodic force
Directory of Open Access Journals (Sweden)
Duong The-Hung
2018-01-01
Full Text Available This report describes a new proposed design for autogenous mobile systems which can move without any external mechanisms such as legs or wheels. A Duffing oscillator with a cubic spring, which is excited by an impulse periodic force, is utilized to drive the whole system. The rectilinear motion of the system is performed employing the periodically oscillation of the internal mass interacting without collisions with the main body. Utilizing the nonlinear restoring force of the cubic spring, the system can move in desired directions. When the ratio between the excitation force and the friction force is smaller than 2.5, backward or forward motion can be easily achieved by applying an excitation force in the same desired direction. Different from other vibro-impact drifting devices, no impact needed to drive the new proposed system. This novel structure allows to miniaturize the device as well as to simplify the control algorithm thus can significantly expand applicability of the proposed system.
20. Electronic-excitation energy transfer in heterogeneous dye solutions under laser excitation
International Nuclear Information System (INIS)
Levshin, L.V.; Mukushev, B.T.; Saletskii, A.M.
1995-01-01
An experimental study has been made of electronic-excitation energy transfer (EEET) among dye molecules of different types for different exciting-fight wavelengths and temperatures. Upon selective laser excitation of the donor, the inhomogeneous broadening of molecular levels increases the probability of EEET from the donor to acceptor molecules. The efficiency of this process is directly proportional to the acceptor molecule concentration and is temperature dependent. The EEET is accompanied by the spectral migration of energy among donor molecules, which reduces the fluorescence quantum efficiency of the donor. Increasing the frequency of the exciting light decreases in the donor fluorescence quantum efficiency. An increase in the acceptor molecule concentration results in a decrease of the spectral migration of excitation in the donor molecule system. 5 refs., 5 figs
1. Magnetic excitations and exchange interactions in the spin-gap system TlCuCl sub 3
CERN Document Server
Oosawa, A; Kato, T; Kakurai, K; Müller, M; Mikeska, H J
2002-01-01
The magnetic excitations from the gapped ground state in TlCuCl sub 3 have been investigated by means of inelastic neutron scattering experiments. The excitation data were collected along four different directions in the a sup * -c sup * plane. A well-defined single magnetic excitation mode was observed. The lowest excitation occurs at Q=(h,0,l) with integer h and odd l, as observed in KCuCl sub 3. The dispersion relations were analyzed by the cluster-series expansion up to the sixth order, so that the individual exchange interactions were evaluated. It was demonstrated that TlCuCl sub 3 is a strongly coupled spin-dimer system. (orig.)
2. Some features of excited states density matrix calculation and their pairing relations in conjugated systems
International Nuclear Information System (INIS)
Giambiagi, M.S. de; Giambiagi, M.
1982-01-01
Direct PPP-type calculations of self-consistent (SC) density matrices for excited states are described and the corresponding 'thawn' molecular orbitals (MO) are discussed. Special attention is addressed to particular solutions arising in conjugated systems of a certain symmetry, and to their chemical implications. The U(2) and U(3) algebras are applied respectively to the 4-electron and 6-electron cases: a natural separation of excited states in different cases follows. A simple approach to the convergence problem for excited states is given. The complementarity relations, an alternative formulation of the pairing theorem valid for heteromolecules and non-alternant systems, allow some fruitful experimental applications. Together with the extended pairing relations shown here, they may help to rationalize general trends. (Author) [pt
3. Synchronisation and general dynamic symmetry of a vibrating system with two exciters rotating in opposite directions
International Nuclear Information System (INIS)
Chun-Yu, Zhao; Yi-Min, Zhang; Bang-Chun, Wen
2010-01-01
We derive the non-dimensional coupling equation of two exciters, including inertia coupling, stiffness coupling and load coupling. The concept of general dynamic symmetry is proposed to physically explain the synchronisation of the two exciters, which stems from the load coupling that produces the torque of general dynamic symmetry to force the phase difference between the two exciters close to the angle of general dynamic symmetry. The condition of implementing synchronisation is that the torque of general dynamic symmetry is greater than the asymmetric torque of the two motors. A general Lyapunov function is constructed to derive the stability condition of synchronisation that the non-dimensional inertia coupling matrix is positive definite and all its elements are positive. Numeric results show that the structure of the vibrating system can guarantee the stability of synchronisation of the two exciters, and that the greater the distances between the installation positions of the two exciters and the mass centre of the vibrating system are, the stronger the ability of general dynamic symmetry is
4. Synchronization of Two Non-Identical Coupled Exciters in a Non-Resonant Vibrating System of Linear Motion. Part II: Numeric Analysis
Directory of Open Access Journals (Sweden)
Chunyu Zhao
2009-01-01
Full Text Available The paper focuses on the quantitative analysis of the coupling dynamic characteristics of two non-identical exciters in a non-resonant vibrating system. The load torque of each motor consists of three items, including the torque of sine effect of phase angles, that of coupling sine effect and that of coupling cosine effect. The torque of frequency capture results from the torque of coupling cosine effect, which is equal to the product of the coupling kinetic energy, the coefficient of coupling cosine effect, and the sine of phase difference of two exciters. The motions of the system excited by two exciters in the same direction make phase difference close to π and that in opposite directions makes phase difference close to 0. Numerical results show that synchronous operation is stable when the dimensionless relative moments of inertia of two exciters are greater than zero and four times of their product is greater than the square of their coefficient of coupling cosine effect. The stability of the synchronous operation is only dependent on the structural parameters of the system, such as the mass ratios of two exciters to the vibrating system, and the ratio of the distance between an exciter and the centroid of the system to the equivalent radius of the system about its centroid.
5. Theoretical and Experimental Study on Synchronization of the Two Homodromy Exciters in a Non-Resonant Vibrating System
Directory of Open Access Journals (Sweden)
Xue-Liang Zhang
2013-01-01
Full Text Available In this paper we give some theoretical analyses and experimental results on synchronization of the two non-identical exciters. Using the average method of modified small parameters, the dimensionless coupling equation of the two exciters is deduced. The synchronization criterion for the two exciters is derived as the torque of frequency capture being equal to or greater than the absolute value of difference between the residual electromagnetic torques of the two motors. The stability criterion of synchronous state is verified to satisfy the Routh-Hurwitz criterion. The regions of implementing synchronization and that of stability of phase difference for the two exciters are manifested by numeric method. Synchronization of the two exciters stems from the coupling dynamic characteristic of the vibrating system having selecting motion, especially, under the condition that the parameters of system are complete symmetry, the torque of frequency capture stemming from the circular motion of the rigid frame drives the phase difference to approach PI and carry out the swing of the rigid frame; that from the swing of the rigid frame forces the phase difference to near zero and achieve the circular motion of the rigid frame. In the steady state, the motion of rigid frame will be one of three types: pure swing, pure circular motion, swing and circular motion coexistence. The numeric and experiment results derived thereof show that the two exciters can operate synchronously as long as the structural parameters of system satisfy the criterion of stability in the regions of frequency capture. In engineering, the distance between the centroid of the rigid frame and the rotational centre of exciter should be as far as possible. Only in this way, can the elliptical motion of system required in engineering be realized.
6. Four-nucleon system with Δ-isobar excitation
International Nuclear Information System (INIS)
Deltuva, A.; Fonseca, A.C.; Sauer, P.U.
2008-01-01
The four-nucleon bound state and scattering below three-body breakup threshold are described based on the realistic coupled-channel potential CD Bonn+Δ which allows the excitation of a single nucleon to a Δ isobar. The Coulomb repulsion between protons is included. In the four-nucleon system the two-baryon coupled-channel potential yields effective two-, three- and four-nucleon forces, mediated by the Δ isobar and consistent with each other and with the underlying two-nucleon force. The effect of the four-nucleon force on the studied observables is much smaller than the effect of the three-nucleon force. The inclusion of the Δ isobar is unable to resolve the existing discrepancies with the experimental data
7. Controllable excitation of higher-order rogue waves in nonautonomous systems with both varying linear and harmonic external potentials
Science.gov (United States)
Jia, Heping; Yang, Rongcao; Tian, Jinping; Zhang, Wenmei
2018-05-01
The nonautonomous nonlinear Schrödinger (NLS) equation with both varying linear and harmonic external potentials is investigated and the semirational rogue wave (RW) solution is presented by similarity transformation. Based on the solution, the interactions between Peregrine soliton and breathers, and the controllability of the semirational RWs in periodic distribution and exponential decreasing nonautonomous systems with both linear and harmonic potentials are studied. It is found that the harmonic potential only influences the constraint condition of the semirational solution, the linear potential is related to the trajectory of the semirational RWs, while dispersion and nonlinearity determine the excitation position of the higher-order RWs. The higher-order RWs can be partly, completely and biperiodically excited in periodic distribution system and the diverse excited patterns can be generated for different parameter relations in exponential decreasing system. The results reveal that the excitation of the higher-order RWs can be controlled in the nonautonomous system by choosing dispersion, nonlinearity and external potentials.
8. Simultaneous excitation system for efficient guided wave structural health monitoring
Science.gov (United States)
Hua, Jiadong; Michaels, Jennifer E.; Chen, Xin; Lin, Jing
2017-10-01
Many structural health monitoring systems utilize guided wave transducer arrays for defect detection and localization. Signals are usually acquired using the ;pitch-catch; method whereby each transducer is excited in turn and the response is received by the remaining transducers. When extensive signal averaging is performed, the data acquisition process can be quite time-consuming, especially for metallic components that require a low repetition rate to allow signals to die out. Such a long data acquisition time is particularly problematic if environmental and operational conditions are changing while data are being acquired. To reduce the total data acquisition time, proposed here is a methodology whereby multiple transmitters are simultaneously triggered, and each transmitter is driven with a unique excitation. The simultaneously transmitted waves are captured by one or more receivers, and their responses are processed by dispersion-compensated filtering to extract the response from each individual transmitter. The excitation sequences are constructed by concatenating a series of chirps whose start and stop frequencies are randomly selected from a specified range. The process is optimized using a Monte-Carlo approach to select sequences with impulse-like autocorrelations and relatively flat cross-correlations. The efficacy of the proposed methodology is evaluated by several metrics and is experimentally demonstrated with sparse array imaging of simulated damage.
9. Non-contact test set-up for aeroelasticity in a rotating turbomachine combining a novel acoustic excitation system with tip-timing
International Nuclear Information System (INIS)
Freund, O; Seume, J R; Montgomery, M; Mittelbach, M
2014-01-01
10. Electronic excited states and relaxation dynamics in polymer heterojunction systems
Science.gov (United States)
Ramon, John Glenn Santos
The potential for using conducting polymers as the active material in optoelectronic devices has come to fruition in the past few years. Understanding the fundamental photophysics behind their operations points to the significant role played by the polymer interface in their performance. Current device architectures involve the use of bulk heterojunctions which intimately blend the donor and acceptor polymers to significantly increase not only their interfacial surface area but also the probability of exciton formation within the vicinity of the interface. In this dissertation, we detail the role played by the interface on the behavior and performance of bulk heterojunction systems. First, we explore the relation between the exciton binding energy to the band offset in determining device characteristics. As a general rule, when the exciton binding energy is greater than the band offset, the exciton remains the lowest energy excited state leading to efficient light-emitting properties. On the other hand, if the offset is greater than the binding energy, charge separation becomes favorable leading to better photovoltaic behavior. Here, we use a Wannier function, configuration interaction based approach to examine the essential excited states and predict the vibronic absorption and emission spectra of the PPV/BBL, TFB/F8BT and PFB/F8BT heterojunctions. Our results underscore the role of vibrational relaxation in the formation of charge-transfer states following photoexcitation. In addition, we look at the relaxation dynamics that occur upon photoexcitation. For this, we adopt the Marcus-Hush semiclassical method to account for lattice reorganization in the calculation of the interconversion rates in TFB/F8BT and PFB/F8BT. We find that, while a tightly bound charge-transfer state (exciplex) remains the lowest excited state, a regeneration pathway to the optically active lowest excitonic state in TFB/F8BT is possible via thermal repopulation from the exciplex. Finally
11. Effects of Isospin on Pre-scission Particle Multiplicity of Heavy Systems and Its Excitation Energy Dependence
Institute of Scientific and Technical Information of China (English)
YE Wei; CHEN Na
2004-01-01
Isospin effects on particle emission of fissioning isobaric sources 202Fr, 202po, 202Tl and isotopic sources 189,202,212Po, and its dependence on the excitation energy are studied via Smoluchowski equations. It is shown that with increasing the isospin of fissioning systems, charged-particle emission is not sensitive to the strength of nuclear dissipation. In addition, we have found that increasing the excitation energy not only increases the influence of nuclear dissipation on particle emission but also greatly enhances the sensitivity of the emission of pre-scission neutrons or charged particles to the isospin of the system. Therefore, in order to extract dissipation strength more accurately by taking light particle multiplicities it is important to choose both a highly excited compound nucleus and a proper kind of particles for systems with different isospins.
12. Excitation-scanning hyperspectral imaging system for microscopic and endoscopic applications
Science.gov (United States)
Mayes, Sam A.; Leavesley, Silas J.; Rich, Thomas C.
2016-04-01
Current microscopic and endoscopic technologies for cancer screening utilize white-light illumination sources. Hyper-spectral imaging has been shown to improve sensitivity while retaining specificity when compared to white-light imaging in both microscopy and in vivo imaging. However, hyperspectral imaging methods have historically suffered from slow acquisition times due to the narrow bandwidth of spectral filters. Often minutes are required to gather a full image stack. We have developed a novel approach called excitation-scanning hyperspectral imaging that provides 2-3 orders of magnitude increased signal strength. This reduces acquisition times significantly, allowing for live video acquisition. Here, we describe a preliminary prototype excitation-scanning hyperspectral imaging system that can be coupled with endoscopes or microscopes for hyperspectral imaging of tissues and cells. Our system is comprised of three subsystems: illumination, transmission, and imaging. The illumination subsystem employs light-emitting diode arrays to illuminate at different wavelengths. The transmission subsystem utilizes a unique geometry of optics and a liquid light guide. Software controls allow us to interface with and control the subsystems and components. Digital and analog signals are used to coordinate wavelength intensity, cycling and camera triggering. Testing of the system shows it can cycle 16 wavelengths at as fast as 1 ms per cycle. Additionally, more than 18% of the light transmits through the system. Our setup should allow for hyperspectral imaging of tissue and cells in real time.
13. Faraday waves under time-reversed excitation.
Science.gov (United States)
Pietschmann, Dirk; Stannarius, Ralf; Wagner, Christian; John, Thomas
2013-03-01
Do parametrically driven systems distinguish periodic excitations that are time mirrors of each other? Faraday waves in a Newtonian fluid are studied under excitation with superimposed harmonic wave forms. We demonstrate that the threshold parameters for the stability of the ground state are insensitive to a time inversion of the driving function. This is a peculiarity of some dynamic systems. The Faraday system shares this property with standard electroconvection in nematic liquid crystals [J. Heuer et al., Phys. Rev. E 78, 036218 (2008)]. In general, time inversion of the excitation affects the asymptotic stability of a parametrically driven system, even when it is described by linear ordinary differential equations. Obviously, the observed symmetry has to be attributed to the particular structure of the underlying differential equation system. The pattern selection of the Faraday waves above threshold, on the other hand, discriminates between time-mirrored excitation functions.
14. Generalization of the variational principle and the Hohenberg and Kohn theorems for excited states of Fermion systems
Energy Technology Data Exchange (ETDEWEB)
Gonis, A., E-mail: [email protected]
2017-01-05
Through the entanglement of a collection of K non-interacting replicas of a system of N interacting Fermions, and making use of the properties of reduced density matrices the variational principle and the theorems of Hohenberg and Kohn are generalized to excited states. The generalization of the variational principle makes use of the natural orbitals of an N-particle density matrix describing the state of lowest energy of the entangled state. The extension of the theorems of Hohenberg and Kohn is based on the ground-state formulation of density functional theory but with a new interpretation of the concept of a ground state: It is the state of lowest energy of a system of KN Fermions that is described in terms of the excited states of the N-particle interacting system. This straightforward implementation of the line of reasoning of ground-state density functional theory to a new domain leads to a unique and logically valid extension of the theory to excited states that allows the systematic treatment of all states in the spectrum of the Hamiltonian of an interacting system. - Highlights: • Use of entanglement in connection with the properties of density matrices. • An anti-symmetric entangled state of order KN expressed in terms of excited states of an interacting N-particle system.
15. Measurement of fusion excitation functions in the system {sup 78}Kr + {sup 100}Mo
Energy Technology Data Exchange (ETDEWEB)
Rehm, K.E.; Jiang, C.L.; Esbensen, H. [and others
1995-08-01
Earlier measurements of fusion reactions involving {sup 78}Kr and {sup 100}Mo projectiles and Ni-targets showed surprisingly large fusion yields at low energies which could not be explained by coupled-channels calculations. The main difference to similar measurements involving the neighboring {sup 86}Kr and {sup 92}Mo isotopes was the different slope of the excitation functions at sub-barrier energies. An analysis of a variety of experiments showed a correlation between the nuclear structure and the slope of the excitation functions, with the {open_quotes}soft{close_quotes} transitional nuclei ({sup 78}Kr, {sup 100}Mo) exhibiting shallower slopes than the {open_quotes}stiff{close_quotes} nuclei ({sup 86}Kr, {sup 92}Mo) measured at the same energies with respect to the barrier. In this experiment we studied the fusion excitation function involving two transitional nuclei {sup 78}Kr + {sup 100}Mo. The measurements were performed with {sup 78}Kr beams from the ECR source at energies between 285-370 MeV. Separation of the evaporation nucleus from the elastically scattered particles was achieved by measuring time-of-flight and magnetic rigidity in the gas-filled spectrograph. The data were completely analyzed. A comparison of the cross sections with measurements for the system {sup 86}Kr + {sup 92}Mo populating the same compound nucleus {sup 178}Pt. It shows good agreement at the highest energies, but quite different falloffs of the excitation functions toward lower energies. Coupled-channels calculations, including multi-phonon excitation for the two systems, are being performed.
16. Development of the system for excitation function automatic measurement of nuclear reactions
International Nuclear Information System (INIS)
Sapozhnikov, A.B.
2004-01-01
Full text: The resonance nuclear reaction method is applied at the tandem accelerator UKP-2-1 to determinate films thickness and obtain light element depth distribution. The system for automatic measurement of the nuclear reaction excitation curve has been developed. It allowed to obtain an excitation function of nuclear reaction using continuous changing potential of the target with energy step of 6 eV. Saw-tooth voltage with amplitude up to 6 kV from the block of scanning beam is fed to a target. The amplitude is determined by constant voltage from the scanning beam block control. Nal(Tl) detector detects gamma quanta - the products of a nuclear reaction and transforms they in voltage impulses. The impulses through the amplifier income in the single-channel analyzer which forms impulses to start the analog-to-digital converter. The value of saw-tooth voltage corresponding to the moment of gamma quantum detection is read by the analog-to-digital converter, where it is transformed to digital code and transmitted to the computer. The computer program has been developed to control the process of accumulation of excitation function. The dependence a detected γ-quanta yield from a target potential is automatically plotted by the program. This dependence corresponds to the nuclear reaction excitation function. If scanning amplitude is not enough in order to scan need depth of a sample, an operator increases energy of the proton beam changing high voltage potential of the terminal up 3 keV and measures the nuclear reaction excitation function with the new energy. This procedure can be repeated some times. After that 'sewing' of excitation functions is carried out by the program under the hypothesis that nuclear reaction yield in last points be identical
17. Role of vortex structures in excitation of self-oscillating combustion of condensed systems
International Nuclear Information System (INIS)
Samsonov, V.P.; Murunov, E.Yu.; Alekseev, M.V.
2008-01-01
One studied experimentally the effect of the free convection and the eddy structures occurring near the gasoline burner singing flame on the excitation conditions of thermal self-oscillations in a tube-resonator. One introduces a procedure to measure the gas column oscillation amplitude. The singing flame height and the flame mass speed at the excitation of the acoustic oscillations are revealed to reduce, while the gasoline burning efficiency is found to increase. By means of the digital photometry one studied the mechanisms of the singing flame temperature field changes within one oscillation period. One derived the hysteresis dependences of the amplitude of the acoustic oscillations on the gasoline diffusion flame thermal power. One brings to the notice a mechanism of the effect of the eddy structures of the excitation of the burning self-oscillation mode of the condensed systems [ru
18. Bifurcations, chaos and adaptive backstepping sliding mode control of a power system with excitation limitation
Energy Technology Data Exchange (ETDEWEB)
Min, Fuhong, E-mail: [email protected]; Wang, Yaoda; Peng, Guangya; Wang, Enrong [School of Electrical and Automation Engineering, Nanjing Normal University, Jiangsu, 210042 (China)
2016-08-15
The bifurcation and Lyapunov exponent for a single-machine-infinite bus system with excitation model are carried out by varying the mechanical power, generator damping factor and the exciter gain, from which periodic motions, chaos and the divergence of system are observed respectively. From given parameters and different initial conditions, the coexisting motions are developed in power system. The dynamic behaviors in power system may switch freely between the coexisting motions, which will bring huge security menace to protection operation. Especially, the angle divergences due to the break of stable chaotic oscillation are found which causes the instability of power system. Finally, a new adaptive backstepping sliding mode controller is designed which aims to eliminate the angle divergences and make the power system run in stable orbits. Numerical simulations are illustrated to verify the effectivity of the proposed method.
19. Bifurcations, chaos and adaptive backstepping sliding mode control of a power system with excitation limitation
Directory of Open Access Journals (Sweden)
Fuhong Min
2016-08-01
Full Text Available The bifurcation and Lyapunov exponent for a single-machine-infinite bus system with excitation model are carried out by varying the mechanical power, generator damping factor and the exciter gain, from which periodic motions, chaos and the divergence of system are observed respectively. From given parameters and different initial conditions, the coexisting motions are developed in power system. The dynamic behaviors in power system may switch freely between the coexisting motions, which will bring huge security menace to protection operation. Especially, the angle divergences due to the break of stable chaotic oscillation are found which causes the instability of power system. Finally, a new adaptive backstepping sliding mode controller is designed which aims to eliminate the angle divergences and make the power system run in stable orbits. Numerical simulations are illustrated to verify the effectivity of the proposed method.
20. Quantification of entanglement entropies for doubly excited resonance states in two-electron atomic systems
International Nuclear Information System (INIS)
Ho, Yew Kam; Lin, Chien-Hao
2015-01-01
In this work, we study the quantum entanglement for doubly excited resonance states in two-electron atomic systems such as the H - and Ps - ions and the He atom by using highly correlated Hylleraas type functions The resonance states are determined by calculation of density of resonance states with the stabilization method. The spatial (electron-electron orbital) entanglement entropies (linear and von Neumann) for the low-lying doubly excited states are quantified using the Schmidt-Slater decomposition method. (paper)
1. X-ray excited optical luminescence studies on the system BaXY (X ...
Home; Journals; Pramana – Journal of Physics; Volume 65; Issue 2. X-ray excited optical luminescence studies on the system Ba (, =F, Cl, Br, I) ... India; Department of Chemical Engineering, National Taiwan University, Republic of China ... Proceedings of the International Workshop/Conference on Computational ...
2. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation
International Nuclear Information System (INIS)
Zhang Hailong; Zhang Ning; Wang Enrong; Min Fuhong
2016-01-01
The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc–Wen force–velocity (F–v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. (paper)
3. Isovector excitations in charge independent systems
International Nuclear Information System (INIS)
Menezes, D.P.
1986-01-01
A method for building states with good isospin, from states given by the action of an isovector excitation operator on states of the parent multiplet is developed. This new method is a generalization of Toki's method and is applicable to cases involving any isovector excitation operator and a parent state, which is not a double magic nucleus. Once obtained these states with well defined isospin, it is shown how to do a Tamm-Dancoff calculation for determining the energy levels. The transition matrix elements of an isotensor operator are also calculated. An application of this formalism to the Gamow-Teller transition strength in 90 Zr is studied. In this case, besides the double magic configuration, the 2 particles - 2 holes (Π1g 9/2 ) 2 (υ 2p 1/2 -1 ) 2 configuration is also considered. (author) [pt
4. Excitation dynamics and relaxation in a molecular heterodimer
International Nuclear Information System (INIS)
Balevičius, V.; Gelzinis, A.; Abramavicius, D.; Mančal, T.; Valkunas, L.
2012-01-01
Highlights: ► Dynamics of excitation within a heterogenous molecular dimer. ► Excited states can be swapped due to different reorganization energies of monomers. ► Conventional excitonic basis becomes renormalized due to interaction with the bath. ► Relaxation is independent of mutual positioning of monomeric excited states. -- Abstract: The exciton dynamics in a molecular heterodimer is studied as a function of differences in excitation and reorganization energies, asymmetry in transition dipole moments and excited state lifetimes. The heterodimer is composed of two molecules modeled as two-level systems coupled by the resonance interaction. The system-bath coupling is taken into account as a modulating factor of the molecular excitation energy gap, while the relaxation to the ground state is treated phenomenologically. Comparison of the description of the excitation dynamics modeled using either the Redfield equations (secular and full forms) or the Hierarchical quantum master equation (HQME) is demonstrated and discussed. Possible role of the dimer as an excitation quenching center in photosynthesis self-regulation is discussed. It is concluded that the system-bath interaction rather than the excitonic effect determines the excitation quenching ability of such a dimer.
5. New excitation equipment for 220 MW generators in Kozloduy NPP
International Nuclear Information System (INIS)
Tomerlin, D.
2001-01-01
Rehabilitation on the excitation equipment for Generator 5, Reactor Unit 3, in Kozloduy NPP was completed in November 2000. ABB's Static Excitation System based on UNITROL 5000 technology has been chosen by the Bulgarian National Utility and Kozloduy NPP to substitute the original Russian excitation system equipment with electro-magnetic voltage regulators. The substitution is in a rehabilitation package of four excitation system equipment for Generator 5 and 6 of Reactor Unit 3 and Generator 7 and 8 of Reactor Unit 4 after a short overview of the original excitation system this paper describes the new Static Excitation System UNITROL 5000 including configuration with block diagram, its main features and merits such as modes of operation, limiter, special control functions and diagnostic facilities. Furthermore, new facilities, which are implemented in UNITROL 5000, such as dynamic current distribution among the thyristors working in parallel as well as the start-up from the residual magnetism are mentioned. Special functions including a so-called free-running mode of operation and automatic change over sequence from new excitation system to the stand-by excitation system, which is DC exciter machine, are described. Some records of the transient responses performed during the commissioning and a photograph of a manufactured system are provided. (author)
6. Optical studies of multiply excited states
International Nuclear Information System (INIS)
Mannervik, S.
1989-01-01
Optical studies of multiply-excited states are reviewed with emphasis on emission spectroscopy. From optical measurements, properties such as excitation energies, lifetimes and autoionization widths can be determined with high accuracy, which constitutes a challenge for modern computational methods. This article mainly covers work on two-, three- and four-electron systems, but also sodium-like quartet systems. Furthermore, some comments are given on bound multiply-excited states in negative ions. Fine structure effects on transition wavelengths and lifetimes (autoionization) are discussed. In particular, the most recent experimental and theoretical studies of multiply-excited states are covered. Some remaining problems, which require further attention, are discussed in more detail. (orig.) With 228 refs
7. Oxygen auroral transition laser system excited by collisional and photolytic energy transfer
International Nuclear Information System (INIS)
Murray, J.R.; Powell, H.T.; Rhodes, C.K.
1975-06-01
The properties of laser media involving the auroral transition of atomic oxygen and analogous systems are examined. A discussion of the atomic properties, collisional mechanisms, excitation processes, and collisionally induced radiative phenomena is given. Crossing phenomena play a particularly important role in governing the dynamics of the medium
8. Early warning signal for interior crises in excitable systems.
Science.gov (United States)
Karnatak, Rajat; Kantz, Holger; Bialonski, Stephan
2017-10-01
The ability to reliably predict critical transitions in dynamical systems is a long-standing goal of diverse scientific communities. Previous work focused on early warning signals related to local bifurcations (critical slowing down) and nonbifurcation-type transitions. We extend this toolbox and report on a characteristic scaling behavior (critical attractor growth) which is indicative of an impending global bifurcation, an interior crisis in excitable systems. We demonstrate our early warning signal in a conceptual climate model as well as in a model of coupled neurons known to exhibit extreme events. We observed critical attractor growth prior to interior crises of chaotic as well as strange-nonchaotic attractors. These observations promise to extend the classes of transitions that can be predicted via early warning signals.
9. Effect of power frequency excitation character on ferroresonance in neutral-grounded system
International Nuclear Information System (INIS)
Hui Meng; Liu Chong-Xin
2010-01-01
In most earlier ferroresonance studies the traditional excitation characteristic of iron core, in which the traditional excitation characteristic contains harmonic voltages or currents, has been used as if it were made up of pure fundamental voltage or current. However, this is not always true. In comparison with traditional excitation characteristics, this paper introduces the power frequency excitation characteristic of the iron core, which contains no harmonics. The power frequency excitation characteristic of iron core has been obtained by Elector Magnetic Transient Program, resulting in discrete voltage and current pairs. Extensive simulations are carried out to analyse the effect of power frequency excitation characteristic on potential transformer ferroresonance. A detailed analysis of simulation results demonstrates that with power frequency excitation characteristic of iron core inclusion at certain excitation voltage the ferroresonance may happen, conversely it may not happen with traditional excitation characteristic inclusion. (general)
10. Photo-redox activated drug delivery systems operating under two photon excitation in the near-IR.
Science.gov (United States)
Guardado-Alvarez, Tania M; Devi, Lekshmi Sudha; Vabre, Jean-Marie; Pecorelli, Travis A; Schwartz, Benjamin J; Durand, Jean-Olivier; Mongin, Olivier; Blanchard-Desce, Mireille; Zink, Jeffrey I
2014-05-07
We report the design and synthesis of a nano-container consisting of mesoporous silica nanoparticles with the pore openings covered by "snap-top" caps that are opened by near-IR light. A photo transducer molecule that is a reducing agent in an excited electronic state is covalently attached to the system. Near IR two-photon excitation causes inter-molecular electron transfer that reduces a disulfide bond holding the cap in place, thus allowing the cargo molecules to escape. We describe the operation of the "snap-top" release mechanism by both one- and two-photon activation. This system presents a proof of concept of a near-IR photoredox-induced nanoparticle delivery system that may lead to a new type of photodynamic drug release therapy.
11. Effect of Various Excitation Conditions on Vibrational Energy in a Multi-Degree-of-Freedom Torsional System with Piecewise-Type Nonlinearities
Directory of Open Access Journals (Sweden)
Jong-Yun Yoon
2015-09-01
Full Text Available Dynamic behaviors in practical driveline systems for wind turbines or vehicles are inherently affected by multiple nonlinearities such as piecewise-type torsional springs. However, various excitation conditions with different levels of magnitudes also show strong relationships to the dynamic behaviors when system responses are examined in both frequency and time domains. This study investigated the nonlinear responses of torsional systems under various excitations by using the harmonic balance method and numerical analysis. In order to understand the effect of piecewise-type nonlinearities on vibrational energy with different excitations, the nonlinear responses were investigated with various comparisons. First, two different jumping phenomena with frequency up- and down-sweeping conditions were determined under severe excitation levels. Second, practical system analysis using the phase plane and Poincaré map was conducted in various ways. When the system responses were composed of quasi-periodic components, Poincaré map analysis clearly revealed the nonlinear dynamic characteristics and thus it is suggested to investigate complicated nonlinear dynamic responses in practical driveline systems.
12. Remodelling of cellular excitation (reaction) and intercellular coupling (diffusion) by chronic atrial fibrillation represented by a reaction-diffusion system
Science.gov (United States)
Zhang, Henggui; Garratt, Clifford J.; Kharche, Sanjay; Holden, Arun V.
2009-06-01
Human atrial tissue is an excitable system, in which myocytes are excitable elements, and cell-to-cell electrotonic interactions are via diffusive interactions of cell membrane potentials. We developed a family of excitable system models for human atrium at cellular, tissue and anatomical levels for both normal and chronic atrial fibrillation (AF) conditions. The effects of AF-induced remodelling of cell membrane ionic channels (reaction kinetics) and intercellular gap junctional coupling (diffusion) on atrial excitability, conduction of excitation waves and dynamics of re-entrant excitation waves are quantified. Both ionic channel and gap junctional coupling remodelling have rate dependent effects on atrial propagation. Membrane channel conductance remodelling allows the propagation of activity at higher rates than those sustained in normal tissue or in tissue with gap junctional remodelling alone. Membrane channel conductance remodelling is essential for the propagation of activity at rates higher than 300/min as seen in AF. Spatially heterogeneous gap junction coupling remodelling increased the risk of conduction block, an essential factor for the genesis of re-entry. In 2D and 3D anatomical models, the dynamical behaviours of re-entrant excitation waves are also altered by membrane channel modelling. This study provides insights to understand the pro-arrhythmic effects of AF-induced reaction and diffusion remodelling in atrial tissue.
13. Synchronization of uncoupled excitable systems induced by white and coloured noise
International Nuclear Information System (INIS)
Zambrano, Samuel; Marino, Ines P; Seoane, Jesus M; Sanjuan, Miguel A F; Euzzor, Stefano; Geltrude, Andrea; Meucci, Riccardo; Arecchi, Fortunato T
2010-01-01
We study, both numerically and experimentally, the synchronization of uncoupled excitable systems due to a common noise. We consider two identical FitzHugh-Nagumo systems, which display both spiking and non-spiking behaviours in chaotic or periodic regimes. An electronic circuit provides a laboratory implementation of these dynamics. Synchronization is tested with both white and coloured noise, showing that coloured noise is more effective in inducing synchronization of the systems. We also study the effects on the synchronization of parameter mismatch and of the presence of intrinsic (not common) noise, and we conclude that the best performance of coloured noise is robust under these distortions.
14. Comparison of sensitivities and detection limits between direct excitation and secondary excitation modes in energy dispersive x-ray fluorescence analysis
International Nuclear Information System (INIS)
Artz, B.E.; Short, M.A.
1976-01-01
A comparison was made between the direct tube excitation mode and the secondary target excitation mode using a Kevex 0810 energy dispersive x-ray fluorescence system. Relative sensitivities and detection limits were determined with two system configurations. The first configuration used a standard, high power, x-ray fluorescence tube to directly excite the specimen. Several x-ray tubes, including chromium, molybdenum, and tungsten, both filtered and not filtered, were employed. The second configuration consisted of using the x-ray tube to excite a secondary target which in turn excited the specimen. Appropriate targets were compared to the direct excitation results. Relative sensitivities and detection limits were determined for K-series lines for elements from magnesium to barium contained in a low atomic number matrix and in a high atomic number matrix
15. Electron excitation of alkali atoms
International Nuclear Information System (INIS)
Ormonde, S.
1979-02-01
The development and testing of a synthesized close-coupling effective model potential ten-channel electron-atom scattering code and some preliminary calculations of resonances in cross sections for the excitation of excited states of potassium by low energy electrons are described. The main results obtained are: identification of 1 S and 1 D structures in excitation cross sections below the 5 2 S threshold of neutral potassium; indications of additional structures - 1 P and 1 D between the 5 2 S and 5 2 D thresholds; and a suggested explanation of anomalously high interstate-electron impact excitation cross sections inferred from experiments on potassium-seeded plasmas. The effective potential model imbedded in the code can be used to simulate any atomic system that can be approximated by a single bound electron outside an ionic core. All that is needed is a set of effective potential parameters--experimental or theoretical. With minor modifications the code could be adapted to calculations of electron scattering by two-electron systems
16. Critical Assessment of TD-DFT for Excited States of Open-Shell Systems: I. Doublet-Doublet Transitions.
Science.gov (United States)
Li, Zhendong; Liu, Wenjian
2016-01-12
A benchmark set of 11 small radicals is set up to assess the performance of time-dependent density functional theory (TD-DFT) for the excited states of open-shell systems. Both the unrestricted (U-TD-DFT) and spin-adapted (X-TD-DFT) formulations of TD-DFT are considered. For comparison, the well-established EOM-CCSD (equation-of-motion coupled-cluster with singles and doubles) is also used. In total, 111 low-lying singly excited doublet states are accessed by all the three approaches. Taking the MRCISD+Q (multireference configuration interaction with singles and doubles plus the Davidson correction) results as the benchmark, it is found that both U-TD-DFT and EOM-CCSD perform well for those states dominated by singlet-coupled single excitations (SCSE) from closed-shell to open-shell, open-shell to vacant-shell, or closed-shell to vacant-shell orbitals. However, for those states dominated by triplet-coupled single excitations (TCSE) from closed-shell to vacant-shell orbitals, both U-TD-DFT and EOM-CCSD fail miserably due to severe spin contaminations. In contrast, X-TD-DFT provides balanced descriptions of both SCSE and TCSE. As far as the functional dependence is concerned, it is found that, when the Hartree-Fock ground state does not suffer from the instability problem, both global hybrid (GH) and range-separated hybrid (RSH) functionals perform grossly better than pure density functionals, especially for Rydberg and charge-transfer excitations. However, if the Hartree-Fock ground state is instable or nearly instable, GH and RSH tend to underestimate severely the excitation energies. The SAOP (statistically averaging of model orbital potentials) performs more uniformly than any other density functionals, although it generally overestimates the excitation energies of valence excitations. Not surprisingly, both EOM-CCSD and adiabatic TD-DFT are incapable of describing excited states with substantial double excitation characters.
17. Nonlinear Dynamical Analysis for the Cable Excited with Parametric and Forced Excitation
Directory of Open Access Journals (Sweden)
C. Z. Qian
2014-01-01
Full Text Available Considering the deck vibration effect on the cable in cable-stayed bridge, using nonlinear structure dynamics theory, the nonlinear dynamical equation for the stayed cable excited with deck vibration is proposed. Research shows that the vertical vibration of the deck has a combined parametric and forced excitation effect on the cable when the angle of the cable is taken into consideration. Using multiscale method, the 1/2 principle parametric resonance is studied and the bifurcation equation is obtained. Despite the parameters analysis, the bifurcation characters of the dynamical system are studied. At last, by means of numerical method and software MATHMATIC, the effect rules of system parameters to the dynamical behavior of the system are studied, and some useful conclusions are obtained.
18. Characterizing Plasmonic Excitations of Quasi-2D Chains
Science.gov (United States)
Townsend, Emily; Bryant, Garnett
A quantum description of the optical response of nanostructures and other atomic-scale systems is desirable for modeling systems that use plasmons for quantum information transfer, or coherent transport and interference of quantum states, as well as systems small enough for electron tunneling or quantum confinement to affect the electronic states of the system. Such a quantum description is complicated by the fact that collective and single-particle excitations can have similar energies and thus will mix. We seek to better understand the excitations of nanosystems to identify which characteristics of the excitations are most relevant to modeling their behavior. In this work we use a quasi 2-dimensional linear atomic chain as a model system, and exact diagonalization of the many-body Hamiltonian to obtain its excitations. We compare this to previous work in 1-d chains which used a combination of criteria involving a many-body state's transfer dipole moment, balance, transfer charge, dynamical response, and induced-charge distribution to identify which excitations are plasmonic in character.
19. Synaptic control of motoneuronal excitability
DEFF Research Database (Denmark)
Rekling, J C; Funk, G D; Bayliss, D A
2000-01-01
important in understanding the transformation of neural activity to motor behavior. Here, we review recent studies on the control of motoneuronal excitability, focusing on synaptic and cellular properties. We first present a background description of motoneurons: their development, anatomical organization......, and membrane properties, both passive and active. We then describe the general anatomical organization of synaptic input to motoneurons, followed by a description of the major transmitter systems that affect motoneuronal excitability, including ligands, receptor distribution, pre- and postsynaptic actions...... and norepinephrine, and neuropeptides, as well as the glutamate and GABA acting at metabotropic receptors, modulate motoneuronal excitability through pre- and postsynaptic actions. Acting principally via second messenger systems, their actions converge on common effectors, e.g., leak K(+) current, cationic inward...
Science.gov (United States)
Johns, C. E.
1987-01-01
The development of an X-band exciter, for use in the X-Band Uplink Subsystem, was completed. The exciter generates the drive signal for the X-band transmitter and also generates coherent test signals for the S- and X-band Block 3 translator and a Doppler reference signal for the Doppler extractor system. In addition to the above, the exciter generates other reference signals that are described. Also presented is an overview of the exciter design and some test data taken on the prototype. A brief discussion of the Block 3 Doppler extractor is presented.
1. ANALYSIS OF THE PROCESSES IN AN INDUCTOR SYSTEM WITH AN ATTRACTING SCREEN EXCITED BY THE EXTERNAL CIRCULAR SOLENOID
Directory of Open Access Journals (Sweden)
E.A. Chaplygin
2015-12-01
Full Text Available Introduction. Developments in the field of magnetic-pulse treatment of metals (MPTM are increasingly used in the modern technologies of production and repair of the aviation, automotive and other machinery, as they are environmentally friendly and energy-efficient in comparison with classical approaches. One of the main components of the device MPTM is a tool – inductor or the inductor system with an attractive screen (ISAS. The calculated dependences to calculate the inductor system with an attractive screen were taken from previous works. The ratios were obtained for the low-frequency mode of the excited fields, when is place their significant penetration through a thin-walled metal screen and a deformed workpiece. As it was shown earlier this mode is the most efficient from point of view of a force action on the object of a processing. Purpose. The theoretical analysis of the spatial-temporal distributions of the induced currents and forces of an attraction in the inductor system with an attractive screen excited by a flat circular solenoid located on the outside of the auxiliary screen. Methodology. The calculations are shown that the induced currents both in the screen and the workpiece are unidirectional and their interaction, in accordance with the law of Ampere determines the amplitudes of excited forces of attraction. Let’s note the effective validity of the considered inductor system excited by an external circular solenoid. With sufficient simplicity of the design take place rather high values of the developed forces of attraction and their averages. Results. Physically, a higher power efficiency of the system with an «external» coil in comparison with a system where coil is located in the internal cavity, can be accounted for lade of «failure» in the radial distribution of the excited forces. This «failure» in the design with a coil between the sheet metal is caused by its screening action against the forces of attraction
2. The dynamic behaviour of a non-stationary elevator compensating rope system under harmonic and stochastic excitations
Energy Technology Data Exchange (ETDEWEB)
Kaczmarczyk, S [School of Applied Sciences, University of Northampton, St. George' s Avenue, Northampton NN2 6JD (United Kingdom); Iwankiewicz, R [Institute of Mechanics and Ocean Engineering, Hamburg University of Technology, Eissendorfer Strasse 42 D-21073, Hamburg (Germany); Terumichi, Y, E-mail: [email protected] [Faculty of Science and Technology, Sophia University, 7-1 KIOI-CHO, CHIYODAKU, Tokyo, 102-8554 Japan (Japan)
2009-08-01
Moving slender elastic elements such as ropes, cables and belts are pivotal components of vertical transportation systems such as traction elevators. Their lengths vary within the host building structure during the elevator operation which results in the change of the mass and stiffness characteristics of the system. The structure of modern high-rise buildings is flexible and when subjected to loads due to strong winds and earthquakes it vibrates at low frequencies. The inertial load induced by the building motion excites the flexible components of the elevator system. The compensating ropes due to their lower tension are particularly affected and undergo large dynamic deformations. The paper focuses on the presentation of the non-stationary model of a building-compensating rope system and on the analysis to predict its dynamic response. The excitation mechanism is represented by a harmonic process and the results of computer simulations to predict transient resonance response are presented. The analysis of the simulation results leads to recommendations concerning the selection of the weight of the compensation assembly to minimize the effects of an adverse dynamic response of the system. The scenario when the excitation is represented as a narrow-band stochastic process with the state vector governed by stochastic equations is then discussed and the stochastic differential equations governing the second-order statistical moments of the state vector are developed.
3. Lattice relaxation theory of localized excitations in quasi-one-dimensional systems
International Nuclear Information System (INIS)
Wang Chuilin; Su Zhaobin; Yu Lu.
1993-04-01
The lattice relaxation theory developed earlier by Su and Yu for solitons and polarons in conducting polymers is applied to systems with both electron-phonon and electron-electron interactions, described by a single band Peierls-Hubbard model. The localized excitations in the competing bond-order-wave (BOW), charge-density-wave (CDW) and spin-density-wave (SDW) systems show interesting new features in their dynamics. In particular, a non-monotonic dependence of the relaxation rate on the coupling strength is predicted from the theory. The possible connection of this effect with photo-luminescence experiments is discussed. Similar phenomena may occur in other quasi-one-dimensional systems as well. (author). 21 refs, 4 figs
4. Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme
International Nuclear Information System (INIS)
Theophilou, Iris; Tassi, M.; Thanos, S.
2014-01-01
Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations
5. Time-dependent theory of Raman scattering for systems with several excited electronic states: Application to a H+3 model system
International Nuclear Information System (INIS)
Heather, R.; Metiu, H.
1989-01-01
The time-dependent formulation of Raman scattering theory is used to study how nonadiabatic interactions affect the Raman spectrum of a model H + 3 system, which has two excited electronic states. We start with a formula derived by Heller which gives the Raman scattering cross section as the Fourier transform (over time) of a time-dependent overlap integral. The latter is calculated with a method proposed by Fleck, Morris, and Feit, and extended to curve crossing by Alvarellos and Metiu. In performing these calculations we are especially interested in displaying effects typical of systems having more than one upper state. If the incident laser populates two electronic states there are several ways (i.e., excite to state one and emit from state two, excite to state one, and emit from state one, etc.) by which the Raman process can reach a given final state, and this leads to quantum interference. This interference is manifested in the Raman cross section as approximate selection rules controlling which final states can be reached through the Raman process. These selection rules depend on the relative orientation of the transition dipoles that radiatively couple the ground electronic state with the excited electronic states. The magnitude of the nonadiabatic contribution to the Raman emission, e.g., the contribution from absorbing to state one and emitting from state two, can be determined from the polarization dependence of the Raman emission if the transition dipoles have neither parallel nor antiparallel relative orientation
6. Quinary excitation method for pulse compression ultrasound measurements.
Science.gov (United States)
Cowell, D M J; Freear, S
2008-04-01
A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter compared to bipolar pseudo-chirp excitation. Pulse compression signal sidelobes are reduced through the use of simple amplitude tapering at the beginning and end of the excitation duration. Amplitude tapering using switched excitation is realised through the use of intermediate voltage switching levels, half that of the main excitation voltages. In total five excitation voltages are used creating a quinary excitation system. The absence of analogue signal generation and power amplifiers renders the excitation method attractive for applications with requirements such as a high channel count or low cost per channel. A systematic study of switched linear frequency modulated excitation methods with simulated and laboratory based experimental verification is presented for 2.25 MHz non-destructive testing immersion transducers. The signal to sidelobe noise level of compressed waveforms generated using quinary and bipolar pseudo-chirp excitation are investigated for transmission through a 0.5m water and kaolin slurry channel. Quinary linear frequency modulated excitation consistently reduces signal sidelobe power compared to bipolar excitation methods. Experimental results for transmission between two 2.25 MHz transducers separated by a 0.5m channel of water and 5% kaolin suspension shows improvements in signal to sidelobe noise power in the order of 7-8 dB. The reported quinary switched method for linear frequency modulated excitation provides improved performance compared to pseudo-chirp excitation without the need for high performance excitation amplifiers.
7. On One Means of Hard Excitation of Oscillations in Nonlinear Flutter Systems
Directory of Open Access Journals (Sweden)
S. D. Glyzin
2014-01-01
Full Text Available Considered are so-called finite-dimensional flutter systems, i.e. systems of ordinary differential equations, arising from Galerkin approximations of certain boundary value problems of aeroelasticity theory as well as from a number of radiophysics applications. We study small oscillations of these equations in case of 1 : 3 resonance. By combining analytical and numerical methods, it is concluded that the mentioned resonance can cause a hard excitation of oscillations. Namely, for flutter systems shown is the possibility of coexistence, along with the stable zero state, of stable invariant tori of arbitrary finite dimension as well as chaotic attractors.
8. Excitation methods for energy dispersive analysis
International Nuclear Information System (INIS)
Jaklevic, J.M.
1976-01-01
The rapid development in recent years of energy dispersive x-ray fluorescence analysis has been based primarily on improvements in semiconductor detector x-ray spectrometers. However, the whole analysis system performance is critically dependent on the availability of optimum methods of excitation for the characteristic x rays in specimens. A number of analysis facilities based on various methods of excitation have been developed over the past few years. A discussion is given of the features of various excitation methods including charged particles, monochromatic photons, and broad-energy band photons. The effects of the excitation method on background and sensitivity are discussed from both theoretical and experimental viewpoints. Recent developments such as pulsed excitation and polarized photons are also discussed
9. RESONANT POST-NEWTONIAN ECCENTRICITY EXCITATION IN HIERARCHICAL THREE-BODY SYSTEMS
Energy Technology Data Exchange (ETDEWEB)
Naoz, Smadar; Kocsis, Bence; Loeb, Abraham [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Yunes, Nicolas, E-mail: [email protected] [Department of Physics, Montana State University, Bozeman, MT 59718 (United States)
2013-08-20
We study the secular, hierarchical three-body problem to first-order in a post-Newtonian expansion of general relativity (GR). We expand the first-order post-Newtonian Hamiltonian to leading-order in the ratio of the semi-major axis of the two orbits. In addition to the well-known terms that correspond to the GR precession of the inner and outer orbits, we find a new secular post-Newtonian interaction term that can affect the long-term evolution of the triple. We explore the parameter space for highly inclined and eccentric systems, where the Kozai-Lidov mechanism can produce large-amplitude oscillations in the eccentricities. The standard lore, i.e., that GR effects suppress eccentricity, is only consistent with the parts of phase space where the GR timescales are several orders of magnitude shorter than the secular Newtonian one. In other parts of phase space, however, post-Newtonian corrections combined with the three-body ones can excite eccentricities. In particular, for systems where the GR timescale is comparable to the secular Newtonian timescales, the three-body interactions give rise to a resonant-like eccentricity excitation. Furthermore, for triples with a comparable-mass inner binary, where the eccentric Kozai-Lidov mechanism is suppressed, post-Newtonian corrections can further increase the eccentricity and lead to orbital flips even when the timescale of the former is much longer than the timescale of the secular Kozai-Lidov quadrupole perturbations.
10. Symmetry characterization of electrons and lattice excitations
Directory of Open Access Journals (Sweden)
Schober H.
2012-03-01
Full Text Available Symmetry concerns all aspects of a physical system from the electronic orbitals to structural and magnetic excitations. In this article we will try to elaborate the fundamental connection between symmetry and excitations. As excitations are manyfold in physical systems it is impossible to treat them exhaustively. We thus concentrate on the two topics of Bloch electrons and phonons. These two examples are complementary in the sense that Bloch electrons describe single particles in an external periodic potential while phonons exemplify a decoupled system of interacting particles. The way we develop the argument gives as by-product a short account of molecular orbitals and molecular vibrations.
11. Topological excitations in magnetic materials
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D., E-mail: [email protected] [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Doria, M.M. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy); Rodrigues, E.I.B. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)
2016-05-20
In this work we propose a new route to describe topological excitations in magnetic systems through a single real scalar field. We show here that spherically symmetric structures in two spatial dimensions, which map helical excitations in magnetic materials, admit this formulation and can be used to model skyrmion-like structures in magnetic materials.
12. Controllability of multi-partite quantum systems and selective excitation of quantum dots
International Nuclear Information System (INIS)
Schirmer, S G; Pullen, I C H; Solomon, A I
2005-01-01
We consider the degrees of controllability of multi-partite quantum systems, as well as necessary and sufficient criteria for each case. The results are applied to the problem of simultaneous control of an ensemble of quantum dots with a single laser pulse. Finally, we apply optimal control techniques to demonstrate selective excitation of individual dots for a simultaneously controllable ensemble of quantum dots
13. Bound state and localization of excitation in many-body open systems
Science.gov (United States)
Cui, H. T.; Shen, H. Z.; Hou, S. C.; Yi, X. X.
2018-04-01
We study the exact bound state and time evolution for single excitations in one-dimensional X X Z spin chains within a non-Markovian reservoir. For the bound state, a common feature is the localization of single excitations, which means the spontaneous emission of excitations into the reservoir is prohibited. Exceptionally, the pseudo-bound state can be found, for which the single excitation has a finite probability of emission into the reservoir. In addition, a critical energy scale for bound states is also identified, below which only one bound state exists, and it is also the pseudo-bound state. The effect of quasirandom disorder in the spin chain is also discussed; such disorder induces the single excitation to locate at some spin sites. Furthermore, to display the effect of bound state and disorder on the preservation of quantum information, the time evolution of single excitations in spin chains is studied exactly. An interesting observation is that the excitation can stay at its initial location with high probability only when the bound state and disorder coexist. In contrast, when either one of them is absent, the information of the initial state can be erased completely or becomes mixed. This finding shows that the combination of bound state and disorder can provide an ideal mechanism for quantum memory.
14. Hysteresis-induced bifurcation and chaos in a magneto-rheological suspension system under external excitation
Science.gov (United States)
Hailong, Zhang; Enrong, Wang; Fuhong, Min; Ning, Zhang
2016-03-01
The magneto-rheological damper (MRD) is a promising device used in vehicle semi-active suspension systems, for its continuous adjustable damping output. However, the innate nonlinear hysteresis characteristic of MRD may cause the nonlinear behaviors. In this work, a two-degree-of-freedom (2-DOF) MR suspension system was established first, by employing the modified Bouc-Wen force-velocity (F-v) hysteretic model. The nonlinear dynamic response of the system was investigated under the external excitation of single-frequency harmonic and bandwidth-limited stochastic road surface. The largest Lyapunov exponent (LLE) was used to detect the chaotic area of the frequency and amplitude of harmonic excitation, and the bifurcation diagrams, time histories, phase portraits, and power spectrum density (PSD) diagrams were used to reveal the dynamic evolution process in detail. Moreover, the LLE and Kolmogorov entropy (K entropy) were used to identify whether the system response was random or chaotic under stochastic road surface. The results demonstrated that the complex dynamical behaviors occur under different external excitation conditions. The oscillating mechanism of alternating periodic oscillations, quasi-periodic oscillations, and chaotic oscillations was observed in detail. The chaotic regions revealed that chaotic motions may appear in conditions of mid-low frequency and large amplitude, as well as small amplitude and all frequency. The obtained parameter regions where the chaotic motions may appear are useful for design of structural parameters of the vibration isolation, and the optimization of control strategy for MR suspension system. Projects supported by the National Natural Science Foundation of China (Grant Nos. 51475246, 51277098, and 51075215), the Research Innovation Program for College Graduates of Jiangsu Province China (Grant No. KYLX15 0725), and the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20131402).
15. Excitability of the T-tubular system in rat skeletal muscle
DEFF Research Database (Denmark)
Nielsen, O B; Ørtenblad, Niels; Lamb, G D
2004-01-01
Strenuous exercise causes an increase in extracellular [K(+)] and intracellular Na(+) ([Na(+)](i)) of working muscles, which may reduce sarcolemma excitability. The excitability of the sarcolemma is, however, to some extent protected by a concomitant increase in the activity of muscle Na(+)-K(+) ...
16. Lattice Boltzmann simulation for the energy and entropy of excitable systems
Institute of Scientific and Technical Information of China (English)
Deng Min-Yi; Tang Guo-Ning; Kong Ling-Jiang; Liu Mu-Ren
2011-01-01
The internal energy and the spatiotemporal entropy of excitable systems are investigated with the lattice Boltzmann method. The numerical results show that the breakup of spiral wave is attributed to the inadequate supply of energy, i.e., the internal energy of system is smaller than the energy of self-sustained spiral wave. It is observed that the average internal energy of a regular wave state reduces with its spatiotemporal entropy decreasing. Interestingly, although the energy difference between two regular wave states is very small, the different states can be distinguished obviously due to the large difference between their spatiotemporal entropies. In addition, when the unstable spiral wave converts into the spatiotemporal chaos, the internal energy of system decreases, while the spatiotemporal entropy increases, which behaves as the thermodynamic entropy in an isolated system.
17. Multireference Density Functional Theory with Generalized Auxiliary Systems for Ground and Excited States.
Science.gov (United States)
Chen, Zehua; Zhang, Du; Jin, Ye; Yang, Yang; Su, Neil Qiang; Yang, Weitao
2017-09-21
To describe static correlation, we develop a new approach to density functional theory (DFT), which uses a generalized auxiliary system that is of a different symmetry, such as particle number or spin, from that of the physical system. The total energy of the physical system consists of two parts: the energy of the auxiliary system, which is determined with a chosen density functional approximation (DFA), and the excitation energy from an approximate linear response theory that restores the symmetry to that of the physical system, thus rigorously leading to a multideterminant description of the physical system. The electron density of the physical system is different from that of the auxiliary system and is uniquely determined from the functional derivative of the total energy with respect to the external potential. Our energy functional is thus an implicit functional of the physical system density, but an explicit functional of the auxiliary system density. We show that the total energy minimum and stationary states, describing the ground and excited states of the physical system, can be obtained by a self-consistent optimization with respect to the explicit variable, the generalized Kohn-Sham noninteracting density matrix. We have developed the generalized optimized effective potential method for the self-consistent optimization. Among options of the auxiliary system and the associated linear response theory, reformulated versions of the particle-particle random phase approximation (pp-RPA) and the spin-flip time-dependent density functional theory (SF-TDDFT) are selected for illustration of principle. Numerical results show that our multireference DFT successfully describes static correlation in bond dissociation and double bond rotation.
18. Scalable implementations of accurate excited-state coupled cluster theories: application of high-level methods to porphyrin based systems
Energy Technology Data Exchange (ETDEWEB)
Kowalski, Karol; Krishnamoorthy, Sriram; Olson, Ryan M.; Tipparaju, Vinod; Apra, Edoardo
2011-11-30
The development of reliable tools for excited-state simulations is emerging as an extremely powerful computational chemistry tool for understanding complex processes in the broad class of light harvesting systems and optoelectronic devices. Over the last years we have been developing equation of motion coupled cluster (EOMCC) methods capable of tackling these problems. In this paper we discuss the parallel performance of EOMCC codes which provide accurate description of the excited-state correlation effects. Two aspects are discuss in details: (1) a new algorithm for the iterative EOMCC methods based on the novel task scheduling algorithms, and (2) parallel algorithms for the non-iterative methods describing the effect of triply excited configurations. We demonstrate that the most computationally intensive non-iterative part can take advantage of 210,000 cores of the Cray XT5 system at OLCF. In particular, we demonstrate the importance of non-iterative many-body methods for achieving experimental level of accuracy for several porphyrin-based system.
19. Critical Assessment of Time-Dependent Density Functional Theory for Excited States of Open-Shell Systems: II. Doublet-Quartet Transitions.
Science.gov (United States)
Li, Zhendong; Liu, Wenjian
2016-06-14
Compared with closed-shell systems, open-shell systems place three additional challenges to time-dependent density functional theory (TD-DFT) for electronically excited states: (a) the spin-contamination problem is a serious issue; (b) the exchange-correlation (XC) kernel may be numerically instable; and (c) the single-determinant description of open-shell ground states readily becomes energetically instable. Confined to flip-up single excitations, the spin-contamination problem can largely be avoided by using the spin-flip TD-DFT (SF-TD-DFT) formalism, provided that a noncollinear XC kernel is employed. As for the numerical instabilities associated with such a kernel, only an ad hoc scheme has been proposed so far, viz., the ALDA0 kernel, which amounts to setting the divergent components (arising from density gradients and kinetic energy density) simply to zero. The ground-state instability problem can effectively be avoided by introducing the Tamm-Dancoff approximation (TDA) to TD-DFT. Therefore, on a general basis, the SF-TDA/ALDA0 Ansatz is so far the only promising means within the TD-DFT framework for flip-up single excitations of open-shell systems. To assess systematically the performance of SF-TDA/ALDA0, in total 61 low-lying quartet excited states of the benchmark set of 11 small radicals [J. Chem. Theory Comput. 2016, 12, 238] are investigated with various XC functionals. Taking the MRCISD+Q (multireference configuration interaction with singles and doubles plus the Davidson correction) results as benchmark, it is found that the mean absolute errors of SF-TDA/ALDA0 with the SAOP (statistical averaging of model orbital potentials), global hybrid, and range-separated hybrid functionals are in the range of 0.2-0.4 eV. This is in line not only with the typical accuracy of TD-DFT for singlet and triplet excited states of closed-shell systems but also with the gross accuracy of spin-adapted TD-DFT for spin-conserving excited states of open-shell systems.
20. Broad-Band Analysis of Polar Motion Excitations
Science.gov (United States)
Chen, J.
2016-12-01
Earth rotational changes, i.e. polar motion and length-of-day (LOD), are driven by two types of geophysical excitations: 1) mass redistribution within the Earth system, and 2) angular momentum exchange between the solid Earth (more precisely the crust) and other components of the Earth system. Accurate quantification of Earth rotational excitations has been difficult, due to the lack of global-scale observations of mass redistribution and angular momentum exchange. The over 14-years time-variable gravity measurements from the Gravity Recovery and Climate Experiment (GRACE) have provided a unique means for quantifying Earth rotational excitations from mass redistribution in different components of the climate system. Comparisons between observed Earth rotational changes and geophysical excitations estimated from GRACE, satellite laser ranging (SLR) and climate models show that GRACE-derived excitations agree remarkably well with polar motion observations over a broad-band of frequencies. GRACE estimates also suggest that accelerated polar region ice melting in recent years and corresponding sea level rise have played an important role in driving long-term polar motion as well. With several estimates of polar motion excitations, it is possible to estimate broad-band noise variance and noise power spectra in each, given reasonable assumptions about noise independence. Results based on GRACE CSR RL05 solutions clearly outperform other estimates with the lowest noise levels over a broad band of frequencies.
1. Can Measured Synergy Excitations Accurately Construct Unmeasured Muscle Excitations?
Science.gov (United States)
Bianco, Nicholas A; Patten, Carolynn; Fregly, Benjamin J
2018-01-01
Accurate prediction of muscle and joint contact forces during human movement could improve treatment planning for disorders such as osteoarthritis, stroke, Parkinson's disease, and cerebral palsy. Recent studies suggest that muscle synergies, a low-dimensional representation of a large set of muscle electromyographic (EMG) signals (henceforth called "muscle excitations"), may reduce the redundancy of muscle excitation solutions predicted by optimization methods. This study explores the feasibility of using muscle synergy information extracted from eight muscle EMG signals (henceforth called "included" muscle excitations) to accurately construct muscle excitations from up to 16 additional EMG signals (henceforth called "excluded" muscle excitations). Using treadmill walking data collected at multiple speeds from two subjects (one healthy, one poststroke), we performed muscle synergy analysis on all possible subsets of eight included muscle excitations and evaluated how well the calculated time-varying synergy excitations could construct the remaining excluded muscle excitations (henceforth called "synergy extrapolation"). We found that some, but not all, eight-muscle subsets yielded synergy excitations that achieved >90% extrapolation variance accounted for (VAF). Using the top 10% of subsets, we developed muscle selection heuristics to identify included muscle combinations whose synergy excitations achieved high extrapolation accuracy. For 3, 4, and 5 synergies, these heuristics yielded extrapolation VAF values approximately 5% lower than corresponding reconstruction VAF values for each associated eight-muscle subset. These results suggest that synergy excitations obtained from experimentally measured muscle excitations can accurately construct unmeasured muscle excitations, which could help limit muscle excitations predicted by muscle force optimizations.
2. Evolutional Properties of Localized Excitations for Generalized Broer-Kaup System in (2+1) Dimensions
International Nuclear Information System (INIS)
Zheng Chunlong; Ye Jianfeng; Xu Yuan
2006-01-01
Using a special Painleve-Baecklund transformation as well as the extended mapping approach and the linear superposition theorem, we obtain new families of variable separation solutions to the (2+1)-dimensional generalized Broer-Kaup (GBK) system. Based on the derived exact solution, we reveal some novel evolutional behaviors of localized excitations, i.e. fission and fusion phenomena in the (2+1)-dimensional GBK system.
3. Influence of Voltage Dips on the Operation of Brushless Exciter System of Synchronous Machines
Directory of Open Access Journals (Sweden)
Fedotov A.
2016-06-01
Full Text Available This paper presents a mathematical model with continuous variables for brushless exciter system of synchronous machines, containing the thyristor elements. Discrete Laplace transform is used for transition from a mathematical model of a system with variable structure in continuous variables to equation finite difference with permanent structure. Then inverse transition is made to a mathematical model in continuous variables with permanent structure.
4. [Study on relationship between emotional stability in flight and nerve system excitability].
Science.gov (United States)
Liu, Fang; Huang, Wei-fen; Jing, Xiao-lu; Zhang, Ping
2003-06-01
To study the related factors of emotional stability in flight. Based on the operable definition of emotional stability in flight and the related literature review, 63 experienced pilots and flight coaches were investigated and the other-rating questionnaire of emotional stability in flight was established. To test the senior nerve system, Uchida Kraeplin (UK) test was administrated on 153 19-21 years old male student pilots of the second grade in the department of flight technique in China Civil Aviation College, who were selected through 13 h flight, 35 h solo flight, and acted as the standardization group. In the end, the correlation was explored between the testing results and their emotional behavioral characteristics in flight. Significant positive correlation was found between emotional feature indexes of emotional stability in flight and excitability in UK test. The excitability in UK test are good predictors for emotional stability in flight.
5. A Dynamic Branch-Switching Method for Parametrically Excited Systems
Directory of Open Access Journals (Sweden)
A.Y.T. Leung
1999-01-01
Full Text Available The branch-switching algorithm in static is applied to steady state dynamic problems. The governing ordinary differential equations are transformed to nonlinear algebraic equations by means of harmonic balance method using multiple frequency components. The frequency components of the (irrational nonlinearity of oscillator are obtained by Fast Fourier Transform and Toeplitz Jacobian method (FFT/TJM. All singularities, folds, flips, period doubling and period bubbling, are computed accurately in an analytical manner. Coexisting solutions can be predicted without using initial condition search. The consistence of both stability criteria in time and frequency domains is discussed. A highly nonlinear parametrically excited system is given as example. All connected solution paths are predicted.
6. Effects of intermediate load on performance limitations in excitation control
Directory of Open Access Journals (Sweden)
Pichai Aree
2008-05-01
Full Text Available The stability of excitation control systems is of great concern in power system operations. In this paper, the effects of intermediate load on performance limitation in excitation control are studied. The results reveal that the open-loop characteristic of synchronous machines flux linkage can be changed from minimum to non-minimum phase at a high level of intermediate load. This change leads to instability of synchronous machines under manual excitation control. A particular emphasis is also given to investigate the fundamental limitations in excitation control, imposed by non-minimum phases with regard to the open-loop right-half-plane (ORHP pole. The study demonstrates the difficulties of excitation control tuning to achieve the desired performance and robustness under the ORHP pole occurrence. Moreover, this paper shows the conditional stability in excitation control loop, where either an increase or decrease of the exciter gain causes a destabilization of the systems stability. Frequency response techniques are used for these investigations.
7. The DSS-14 C-band exciter
Science.gov (United States)
Rowan, D. R.
1989-01-01
The development and implementation of a C-band exciter for use with the Block IV Receiver-Exciter Subsystem at Deep Space Station 14 (DSS-14) has been completed. The exciter supplements the standard capabilities of the Block IV system by providing a drive signal for the C-band transmitter while generating coherent translation frequencies for C-band (5-GHz) to S-band (2.2- to 2.3-GHz) Doppler extraction, C-band to L-band (1.6-GHz) zero delay measurements, and a level calibrated L-band test signal. Exciter functions are described, and a general explanation and description of the C-band uplink controller is presented.
8. Stabilization of nonlinear excitations by disorder
DEFF Research Database (Denmark)
Christiansen, Peter Leth; Gaididei, Yuri Borisovich; Johansson, M.
1998-01-01
Using analytical and numerical techniques we analyze the static and dynamical properties of solitonlike excitations in the presence of parametric disorder in the one-dimensional nonlinear Schrodinger equation with a homogeneous power nonlinearity. Both the continuum and the discrete problem...... are investigated. We find that otherwise unstable excitations can be stabilized by the presence of disorder in the continuum problem. For the very narrow excitations of the discrete problem we find that the disorder has no effect on the averaged behavior. Finally, we show that the disorder can be applied to induce...... a high degree of controllability of the spatial extent of the stable excitations in the continuum system....
9. On Emulation of Flueric Devices in Excitable Chemical Medium.
Science.gov (United States)
2016-01-01
Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ) medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.
10. On Emulation of Flueric Devices in Excitable Chemical Medium.
Directory of Open Access Journals (Sweden)
Full Text Available Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.
11. Cryogenic exciter
Science.gov (United States)
Bray, James William [Niskayuna, NY; Garces, Luis Jose [Niskayuna, NY
2012-03-13
The disclosed technology is a cryogenic static exciter. The cryogenic static exciter is connected to a synchronous electric machine that has a field winding. The synchronous electric machine is cooled via a refrigerator or cryogen like liquid nitrogen. The static exciter is in communication with the field winding and is operating at ambient temperature. The static exciter receives cooling from a refrigerator or cryogen source, which may also service the synchronous machine, to selected areas of the static exciter and the cooling selectively reduces the operating temperature of the selected areas of the static exciter.
12. Process and system for isotope separation using the selective vibrational excitation of molecules
International Nuclear Information System (INIS)
Woodroffe, J.A.; Keck, J.C.
1976-01-01
This invention concerns the separation of isotopes by using the isotopically selective vibrational excitation and the vibration-translation reactions of the excited particles. UF 6 molecular mixed with a carrier gas, such as argon, are directed through a refrigerated chamber lighted by a laser radiation tuned to excite vibrationally the uranium hexafluoride molecules of a particular uranium isotope. The density of the carrier gas is preferably maintained above the density of the uranium hexafluoride to allow a greater collision probability of the vibrationally excited molecules with a carried molecule. In such a case, the vibrationally excited uranium hexafluoride will collide with a carrier gas molecule provoking the conversion of the excitation energy into a translation of the excited molecule, resulting in thermal energy or greater diffusibility than that of the other uranium hexafluoride molecules [fr
13. Amplitude control of the track-induced self-excited vibration for a maglev system.
Science.gov (United States)
Zhou, Danfeng; Li, Jie; Zhang, Kun
2014-09-01
The Electromagnet Suspension (EMS) maglev train uses controlled electromagnetic forces to achieve suspension, and self-excited vibration may occur due to the flexibility of the track. In this article, the harmonic balance method is applied to investigate the amplitude of the self-excited vibration, and it is found that the amplitude of the vibration depends on the voltage of the power supplier. Based on this observation, a vibration amplitude control method, which controls the amplitude of the vibration by adjusting the voltage of the power supplier, is proposed to attenuate the vibration. A PI controller is designed to control the amplitude of the vibration at a given level. The effectiveness of this method shows a good prospect for its application to commercial maglev systems. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Burden, M.St.J.; Cross, K.B.
1979-01-01
An investigation into the use of rf sputtering for ion cleaning of insulating substrates before ion plating is reported. Initial experiments consisted of sputtering metals with rf power followed by the deposition of copper onto glass slides using rf plasma excitation and biasing supply. It was found that good quality films were obtained by rf ion plating onto plastics with excellent adhesion over a wide operating pressure range. A block schematic of the rf plasma excitation system is shown. (UK)
15. Subharmonic response of a single-degree-of-freedom nonlinear vibro-impact system to a narrow-band random excitation.
Science.gov (United States)
Haiwu, Rong; Wang, Xiangdong; Xu, Wei; Fang, Tong
2009-08-01
The subharmonic response of single-degree-of-freedom nonlinear vibro-impact oscillator with a one-sided barrier to narrow-band random excitation is investigated. The narrow-band random excitation used here is a filtered Gaussian white noise. The analysis is based on a special Zhuravlev transformation, which reduces the system to one without impacts, or velocity jumps, thereby permitting the applications of asymptotic averaging over the "fast" variables. The averaged stochastic equations are solved exactly by the method of moments for the mean-square response amplitude for the case of linear system with zero offset. A perturbation-based moment closure scheme is proposed and the formula of the mean-square amplitude is obtained approximately for the case of linear system with nonzero offset. The perturbation-based moment closure scheme is used once again to obtain the algebra equation of the mean-square amplitude of the response for the case of nonlinear system. The effects of damping, detuning, nonlinear intensity, bandwidth, and magnitudes of random excitations are analyzed. The theoretical analyses are verified by numerical results. Theoretical analyses and numerical simulations show that the peak amplitudes may be strongly reduced at large detunings or large nonlinear intensity.
16. Excitation-energy influence at the scission configuration
Directory of Open Access Journals (Sweden)
Ramos D.
2017-01-01
Full Text Available Transfer- and fusion-induced fission in inverse kinematics was proven to be a powerful tool to investigate nuclear fission, widening the information of the fission fragments and the access to unstable fissioning systems with respect to other experimental approaches. An experimental campaign for fission investigation has being carried out at GANIL with this technique since 2008. In these experiments, a beam of 238U, accelerated to 6.1 MeV/u, impinges on a 12C target. Fissioning systems from U to Cf are populated through transfer and fusion reactions, with excitation energies that range from few MeV up to 46 MeV. The use of inverse kinematics, the SPIDER telescope, and the VAMOS spectrometer permitted the characterization of the fissioning system in terms of mass, nuclear charge, and excitation energy, and the isotopic identification of the full fragment distribution. The neutron excess, the total neutron multiplicity, and the even-odd staggering in the nuclear charge of fission fragments are presented as a function of the excitation energy of the fissioning system. Structure effects are observed at Z∼50 and Z∼55, where their impact evolves with the excitation energy.
17. Few Issues Related to an Electrodynamic Exciter Control
OpenAIRE
Čala, M.
2015-01-01
There are multiple problems to solve when controlling an electromagnetic exciter for vibrations generation. Main challenge is to straighten a frequency response of an exciter which is normally not uniform due to resonances resulting from the mechanical construction of an exciter, specimen to test, or mounting fixture. This paper describes number of aspects to consider, which arose during implementation of the control system for small electrodynamic exciter on the Department of Control and Ins...
18. Excited State Spectra and Dynamics of Phenyl-Substituted Butadienes
DEFF Research Database (Denmark)
Wallace-Williams, Stacie E.; Schwartz, Benjamin J.; Møller, Søren
1994-01-01
indicate that phenyl torsional motion is not important to the excited-state dynamics and reveal alternative excited-state reaction pathways. The results demonstrate how molecular systems that are structually similar can exhibit different electronic properties and excited-state dynamics....
19. Nonlinear response to the multiple sine wave excitation of a softening--hardening system
International Nuclear Information System (INIS)
Koplik, B.; Subudhi, M.; Curreri, J.
1979-01-01
In studying the earthquake response of the HTGR core, it was observed that the system can display softening--hardening characteristics. This is of great consequence in evaluating the structural safety aspects of the core. In order to obtain a better understanding of the governing parameters, an investigation was undertaken with a single-degree-of-freedom system having a softening--hardening spring characteristic and excited by multiple sine waves. A parametric study varying the input amplitudes and the spring characteristic was performed. Transients were introduced into the system, and the jump phenomena between the lower softening characteristics to the higher hardening curve was studied
20. Increasing Mud Pump Motor Reliability against Malfunctions of DC Motor Excitation System
Science.gov (United States)
Nikulin, O. V.; Shabanov, V. A.
2017-10-01
The most widely used drilling machinery, such as mud pumps, draw-works, and rotors, use direct-current (DC) motors with independent excitation as the electric drive. Drilling machinery drives operate in harsh ambient conditions, including those with the presence of moisture, dust and vibration, which increases the malfunction rate of both drilling equipment and their electric drives. One of the frequently encountered malfunctions are DC motor excitation coil faults, which disrupt the normal functioning of electric drives, often leading to shutdown of the drilling process. In a four-pole DC motor, the malfunction of one coil leads to lack of excitation current in just one coil pair, while the other pair remains functional. In this case, DC motors and drilling equipment can remain operational, which would allow for continuing the drilling process. This paper considers the possibility of operation of a DC motor on a drilling rig in those cases when one pair of excitation coils is non-functional, and describes the device for switching between the excitation coils and the auxiliary winding in a DC motor with independent excitation.
1. A truncated spherical shell model for nuclear collective excitations: Applications to the odd-mass systems, neutron-proton systems, and other topics
International Nuclear Information System (INIS)
Wu, Hua.
1989-01-01
One of the most elusive quantum system in nature is the nucleus, which is a strongly interacting many body system. In the hadronic (a la neutrons and protons) phase, the primary concern of this thesis, the nucleus' single particle excitations are intertwined with their various collective excitations. Although the underpinning of the nucleus is the spherical shell model, it is rendered powerless without a severe, but intelligent truncation of the infinite Hilbert space. The recently proposed Fermion Dynamical Symmetry Model (FDSM) is precisely such a truncation scheme and in which a symmetry-dictated truncation scheme is introduced in nuclear physics for the first time. In this thesis, extensions and explorations of the FDSM are made to specifically study the odd mass (where the most intricate mixing of the single particle and the collective excitations are observed) and the neutron-proton systems. In particular, the author finds that the previously successful phenomenological particle-rotor-model of the Copenhagen school can now be well understood microscopically via the FDSM. Furthermore, the well known Coriolis attenuation and variable moment of inertia effects are naturally understood from the model as well. A computer code FDUO was written by one of us to study, for the first time, the numerical implications of the FDSM. Several collective modes were found even when the system does not admit a group chain description. In addition, the code is most suitable to study the connection between level statistical behavior (a at Gaussian Orthogonal Ensemble) and dynamical symmetry. It is found that there exist critical region of the interaction parameter space were the system behaves chaotically. This information is certainly crucial to understanding quantum chaotic behavior
2. Vector boson excitations near deconfined quantum critical points.
Science.gov (United States)
Huh, Yejin; Strack, Philipp; Sachdev, Subir
2013-10-18
We show that the Néel states of two-dimensional antiferromagnets have low energy vector boson excitations in the vicinity of deconfined quantum critical points. We compute the universal damping of these excitations arising from spin-wave emission. Detection of such a vector boson will demonstrate the existence of emergent topological gauge excitations in a quantum spin system.
3. Ion-Beam-Excited Electrostatic Ion Cyclotron Waves
DEFF Research Database (Denmark)
Michelsen, Poul; Pécseli, Hans; Juul Rasmussen, Jens
1976-01-01
Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field.......Self-excited electrostatic ion cyclotron waves were observed in an ion-beam-plasma system produced in a DP-operated Q-machine. The frequency of the waves showed the theoretically predicted variation with the magnetic field....
4. Charge and energy dynamics in photo-excited poly(para-phenylenevinylene) systems
International Nuclear Information System (INIS)
Gisslen, L.; Johansson, A.; Stafstroem, S.
2004-01-01
We report results from simulations of charge and energy dynamics in poly(para-phenylenevinylene) (PPV) and PPV interacting with C 60 . The simulations were performed by solving the time-dependent Schroedinger equation and the lattice equation of motion simultaneously and nonadiabatically. The electronic system and the coupling of the electrons to the lattice were described by an extended three-dimensional version of the Su-Schrieffer-Heeger model, which also included an external electric field. Electron and lattice dynamics following electronic excitations at different energies have been simulated. The effect of additional lattice energy was also included in the simulations. Our results show that both exciton diffusion and transitions from high to lower lying excitations are stimulated by increasing the lattice energy. Also field induced charge separation occurs faster if the lattice energy is increased. This separation process is highly nonadiabatic and involves a significant rearrangement of the electron distribution. In the case of PPV coupled to C 60 , we observe a spontaneous charge separation. The separation time is in this case limited by the local concentration of C 60 molecules close to the PPV chain
5. Dynamic response of tertiary systems in structures subjected to base excitation
International Nuclear Information System (INIS)
Hernried, A.G.; Kai-sing Lau
1988-01-01
The dynamic response of very lightweight equipment (tertiary subsystem) attached to light equipment (secondary subsystem) which in turn is attached to a heavier structure (primary subsystem) that is subjected to ground shock or earthquake excitation is investigated. Both the single-degree-of-freedom and multi-degree-of-freedom subsystem models are considered. The systems are damped as well as undamped, completely detuned (all natural frequencies of the subsystems well spaced), singly tuned (one natural frequency of each subsystem equal or close to one another), or multiply tuned (more than one natural frequency of the subsystems close to each other). Efficient techniques for the determination of the tertiary subsystem response that avoid a computationally intensive numerical integration of the combined system equations are presented. (author)
6. Crossed-coil detection of two-photon excited nuclear quadrupole resonance
Science.gov (United States)
Eles, Philip T.; Michal, Carl A.
2005-08-01
Applying a recently developed theoretical framework for determining two-photon excitation Hamiltonians using average Hamiltonian theory, we calculate the excitation produced by half-resonant irradiation of the pure quadrupole resonance of a spin-3/2 system. This formalism provides expressions for the single-quantum and double-quantum nutation frequencies as well as the Bloch-Siegert shift. The dependence of the excitation strength on RF field orientation and the appearance of the free-induction signal along an axis perpendicular to the excitation field provide an unmistakable signature of two-photon excitation. We demonstrate single- and double-quantum excitation in an axially symmetric system using 35Cl in a single crystal of potassium chlorate ( ωQ = 28 MHz) with crossed-coil detection. A rotation plot verifies the orientation dependence of the two-photon excitation, and double-quantum coherences are observed directly with the application of a static external magnetic field.
7. Performance Evaluation on Transmission Tower-Line System with Passive Friction Dampers Subjected to Wind Excitations
Directory of Open Access Journals (Sweden)
Bo Chen
2015-01-01
Full Text Available The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.
8. Orientation of nuclei excited by polarized neutrons
International Nuclear Information System (INIS)
Lifshits, E.P.
1986-01-01
Polarization and radiation angular distribution of oriented nuclei in inelastic scattering of polarized neutrons were investigated. Nucleus orientation in the final state was described by polarization density matrix (PDM). If PDM is known, angular distributions, linear and circular polarization of γ-quanta emitted by a nucleus can be determined. Analytical expression for PDM, conditions of its diagonalization in the case of direct nucleus excitation and excitation by the stage of compound nucleus were obtained. Orientation of 12 C nuclei in the excited state 4.439 MeV, 2 + at energy of incident neutrons in the laboratory system from 4.8 MeV (excitation threshold) upt to 9 MeV was calculated as an example. Neutrons in initial state are completely polarized along Z axis. Calculations showed that excitation proceeds mainly by the stage of compound nucleus formation and 12 C nucleus is highly polarized in excited state
9. Adapting a compact confocal microscope system to a two-photon excitation fluorescence imaging architecture.
Science.gov (United States)
Diaspro, A; Corosu, M; Ramoino, P; Robello, M
1999-11-01
Within the framework of a national National Institute of Physics of Matter (INFM) project, we have realised a two-photon excitation (TPE) fluorescence microscope based on a new generation commercial confocal scanning head. The core of the architecture is a mode-locked Ti:Sapphire laser (Tsunami 3960, Spectra Physics Inc., Mountain View, CA) pumped by a high-power (5 W, 532 nm) laser (Millennia V, Spectra Physics Inc.) and an ultracompact confocal scanning head, Nikon PCM2000 (Nikon Instruments, Florence, Italy) using a single-pinhole design. Three-dimensional point-spread function has been measured to define spatial resolution performances. The TPE microscope has been used with a wide range of excitable fluorescent molecules (DAPI, Fura-2, Indo-1, DiOC(6)(3), fluoresceine, Texas red) covering a single photon spectral range from UV to green. An example is reported on 3D imaging of the helical structure of the sperm head of the Octopus Eledone cirrhosa labelled with an UV excitable dye, i.e., DAPI. The system can be easily switched for operating both in conventional and two-photon mode. Copyright 1999 Wiley-Liss, Inc.
10. Excited State Structural Dynamics of Carotenoids and ChargeTransfer Systems
Energy Technology Data Exchange (ETDEWEB)
Van Tassle, Aaron Justin [Univ. of California, Berkeley, CA (United States)
2006-01-01
This dissertation describes the development andimplementation of a visible/near infrared pump/mid-infrared probeapparatus. Chapter 1 describes the background and motivation ofinvestigating optically induced structural dynamics, paying specificattention to solvation and the excitation selection rules of highlysymmetric molecules such as carotenoids. Chapter 2 describes thedevelopment and construction of the experimental apparatus usedthroughout the remainder of this dissertation. Chapter 3 will discuss theinvestigation of DCM, a laser dye with a fluorescence signal resultingfrom a charge transfer state. By studying the dynamics of DCM and of itsmethyl deuterated isotopomer (an otherwise identical molecule), we areable to investigate the origins of the charge transfer state and provideevidence that it is of the controversial twisted intramolecular (TICT)type. Chapter 4 introduces the use of two-photon excitation to the S1state, combined with one-photon excitation to the S2 state of thecarotenoid beta-apo-8'-carotenal. These 2 investigations show evidencefor the formation of solitons, previously unobserved in molecular systemsand found only in conducting polymers Chapter 5 presents an investigationof the excited state dynamics of peridinin, the carotenoid responsiblefor the light harvesting of dinoflagellates. This investigation allowsfor a more detailed understanding of the importance of structuraldynamics of carotenoids in light harvesting.
11. The Design and Implementation of Test System Based on Programmable Excitation Power Supply for Mining Comprehensive Protector
Directory of Open Access Journals (Sweden)
Zhi-jie Zhang
2013-11-01
Full Text Available As comprehensive protectors for coal mining (referred to comprehensive protectors in use are prone to fail, it can timely screen out the invalid comprehensive protector by periodic functional test when it is used (it is called test in use to ensure the production safety. The test in use needs the specialized test equipment, which is not used in delivery inspection by the manufacturers of comprehensive protectors. Thus, testing excitation power becomes a constraint for the improvement of the accuracy of test in use and the degree of automation. To solve the problem, this paper developed a power frequency programmed input-output testing excitation power supply, and on that basis it also realized the mining comprehensive protector test system in use with the excitation circuit and voltage program-controlled output.
12. Low-lying excited states by constrained DFT
Science.gov (United States)
Ramos, Pablo; Pavanello, Michele
2018-04-01
Exploiting the machinery of Constrained Density Functional Theory (CDFT), we propose a variational method for calculating low-lying excited states of molecular systems. We dub this method eXcited CDFT (XCDFT). Excited states are obtained by self-consistently constraining a user-defined population of electrons, Nc, in the virtual space of a reference set of occupied orbitals. By imposing this population to be Nc = 1.0, we computed the first excited state of 15 molecules from a test set. Our results show that XCDFT achieves an accuracy in the predicted excitation energy only slightly worse than linear-response time-dependent DFT (TDDFT), but without incurring into problems of variational collapse typical of the more commonly adopted ΔSCF method. In addition, we selected a few challenging processes to test the limits of applicability of XCDFT. We find that in contrast to TDDFT, XCDFT is capable of reproducing energy surfaces featuring conical intersections (azobenzene and H3) with correct topology and correct overall energetics also away from the intersection. Venturing to condensed-phase systems, XCDFT reproduces the TDDFT solvatochromic shift of benzaldehyde when it is embedded by a cluster of water molecules. Thus, we find XCDFT to be a competitive method among single-reference methods for computations of excited states in terms of time to solution, rate of convergence, and accuracy of the result.
13. Coulomb excitation
International Nuclear Information System (INIS)
McGowan, F.K.; Stelson, P.H.
1974-01-01
The theory of Coulomb excitation and a brief review of pertinent treatments of the Coulomb excitation process that are useful for the analysis of experiments are given. Examples demonstrating the scope of nuclear structure information obtainable from gamma spectroscopy are presented. Direct Elambda excitation of 232 Th is discussed in terms of the one phonon octupole vibrational spectrum. B(MI) reduced transition probabilities resulting from Coulomb excitation of odd-A deformed nuclei with heavy ions are presented as a test of the rotational model. The use of gamma ray coincidence and particle-gamma coincidence as tools for investigating Coulomb excitation is discussed. (U.S.)
14. Nested variant of the method of moments of coupled cluster equations for vertical excitation energies and excited-state potential energy surfaces.
Science.gov (United States)
Kowalski, Karol
2009-05-21
In this article we discuss the problem of proper balancing of the noniterative corrections to the ground- and excited-state energies obtained with approximate coupled cluster (CC) and equation-of-motion CC (EOMCC) approaches. It is demonstrated that for a class of excited states dominated by single excitations and for states with medium doubly excited component, the newly introduced nested variant of the method of moments of CC equations provides mathematically rigorous way of balancing the ground- and excited-state correlation effects. The resulting noniterative methodology accounting for the effect of triples is tested using its parallel implementation on the systems, for which iterative CC/EOMCC calculations with full inclusion of triply excited configurations or their most important subset are numerically feasible.
15. Synchronization of Two Non-Identical Coupled Exciters in a Non-Resonant Vibrating System of Linear Motion. Part I: Theoretical Analysis
Directory of Open Access Journals (Sweden)
Chunyu Zhao
2009-01-01
Full Text Available In this paper an analytical approach is proposed to study the feature of frequency capture of two non-identical coupled exciters in a non-resonant vibrating system. The electromagnetic torque of an induction motor in the quasi-steady-state operation is derived. With the introduction of two perturbation small parameters to average angular velocity of two exciters and their phase difference, we deduce the Equation of Frequency Capture by averaging two motion equations of two exciters over their average period. It converts the synchronization problem of two exciters into that of existence and stability of zero solution for the Equation of Frequency Capture. The conditions of implementing frequency capture and that of stabilizing synchronous operation of two motors have been derived. The concept of torque of frequency capture is proposed to physically explain the peculiarity of self-synchronization of the two exciters. An interesting conclusion is reached that the moments of inertia of the two exciters in the Equation of Frequency Capture reduce and there is a coupling moment of inertia between the two exciters. The reduction of moments of inertia and the coupling moment of inertia have an effect on the stability of synchronous operation.
16. Self-excited vibration control for axially fast excited beam by a time delay state feedback
International Nuclear Information System (INIS)
Hamdi, Mustapha; Belhaq, Mohamed
2009-01-01
This work examines the control of self-excited vibration of a simply-supported beam subjected to an axially high-frequency excitation. The investigation of the resonant cases are not considered in this paper. The control is implemented via a corrective position feedback with time delay. The objective of this control is to eliminate the undesirable self-excited vibrations with an appropriate choice of parameters. The issue of stability is also addressed in this paper. Using the technique of direct partition of motion, the dynamic of discretized equations is separated into slow and fast components. The multiple scales method is then performed on the slow dynamic to obtain a slow flow for the amplitude and phase. Analysis of this slow flow provides analytical approximations locating regions in parameters space where undesirable self-excited vibration can be eliminated. A numerical study of these regions is performed on the original discretized system and compared to the analytical prediction showing a good agreement.
17. Multireference excitation energies for bacteriochlorophylls A within light harvesting system 2
DEFF Research Database (Denmark)
Anda, Andre; Hansen, Thorsten; De Vico, Luca
2016-01-01
Light-harvesting system 2 (LH2) of purple bacteria is one of the most popular antenna complexes used to study Nature's way of collecting and channeling solar energy. The dynamics of the absorbed energy is probed by ultrafast spectroscopy. Simulation of these experiments relies on fitting a range...... bacteriochlorophylls in LH2. We find that the excitation energies vary among the bacteriochlorophyll monomers and that they are regulated by the curvature of the macrocycle ring and the dihedral angle of an acetyl moiety. Increasing the curvature lifts the ground state energy, which causes a red shift...
18. Slow cortical potential and theta/beta neurofeedback training in adults: effects on attentional processes, and motor system excitability
Directory of Open Access Journals (Sweden)
Petra eStuder
2014-07-01
Full Text Available Neurofeedback (NF is being successfully applied, among others, in children with ADHD and as a peak performance training in healthy subjects. However, the neuronal mechanisms mediating a successful NF training have not yet been sufficiently uncovered for both theta/beta (T/B, and slow cortical potential (SCP training, two protocols established in NF in ADHD. In the present randomized controlled investigation in adults without a clinical diagnosis (n = 59, the specificity of the effects of these two NF protocols on attentional processes, and motor system excitability were to be examined, focusing on the underlying neuronal mechanisms. NF training consisted of 10 double sessions, and self-regulation skills were analyzed. Pre- and post-training assessments encompassed performance and event-related potential measures during an attention task, and motor system excitability assessed by transcranial magnetic stimulation. Some NF protocol specific effects have been obtained. However, due to the limited sample size medium effects didn’t reach the level of significance. Self-regulation abilities during negativity trials of the SCP training were associated with increased contingent negative variation amplitudes, indicating improved resource allocation during cognitive preparation. Theta/beta training was associated with increased response speed and decreased target-P3 amplitudes after successful theta/beta regulation suggested reduced attentional resources necessary for stimulus evaluation. Motor system excitability effects after theta/beta training paralleled the effects of methylphenidate. Overall, our results are limited by the non-sufficiently acquired self-regulation skills, but some specific effects between good and poor learners could be described. Future studies with larger sample sizes and sufficient acquisition of self-regulation skills are needed to further evaluate the protocol specific effects on attention and motor system excitability
19. Response of a Duffing—Rayleigh system with a fractional derivative under Gaussian white noise excitation
International Nuclear Information System (INIS)
Zhang Ran-Ran; Xu Wei; Yang Gui-Dong; Han Qun
2015-01-01
In this paper, we consider the response analysis of a Duffing–Rayleigh system with fractional derivative under Gaussian white noise excitation. A stochastic averaging procedure for this system is developed by using the generalized harmonic functions. First, the system state is approximated by a diffusive Markov process. Then, the stationary probability densities are derived from the averaged Itô stochastic differential equation of the system. The accuracy of the analytical results is validated by the results from the Monte Carlo simulation of the original system. Moreover, the effects of different system parameters and noise intensity on the response of the system are also discussed. (paper)
20. Exciter For X-Band Transmitter And Receiver
Science.gov (United States)
Johns, Carl E.
1989-01-01
Report describes developmental X-band exciter for X-band uplink subsystem of Deep Space Network. X-band transmitter-exciting signal expected to have fractional frequency stability of 5.2 X 10 to negative 15th power during 1,000-second integration period. Generates coherent test signals for S- and X-band Block III translator of Deep Space Network, Doppler-reference signal for associated Doppler-extractor system, first-local-oscillator signal for associated receiver, and reference signal for associated ranging subsystem. Tests of prototype exciter show controlling and monitoring and internal phase-correcting loops perform according to applicable design criteria. Measurements of stability of frequency and of single-sideband noise spectral density of transmitter-exciting signal made subsequently.
1. Excitations and phase transitions in random anti-ferromagnets
International Nuclear Information System (INIS)
Cowley, R.A.; Birgeneau, R.J.; Shirane, G.
1979-01-01
Neutron scattering techniques can be used to study the magnetic excitations and phase transitions in the randomly mixed transition metal fluorides. The results for the excitations of samples with two different types of magnetic ions show two bands of excitations; each associated with excitations propagating largely on one type of ion. In the diluted salts the spectra show a complex line shape and greater widths. These results are in good accord with computer simulations showing that linear spin wave theory can be used, but have not been described satisfactorily using the coherent potential approximation. The phase transitions in these materials are always smeared, but it is difficult to ascertain if this smearing is due to macroscopic fluctuations in the concentration or of an intrinsic origin. Studies of these systems close to the percolation point have shown that the thermal disorder is associated with the one-dimensional weak links of the large clusters. Currently theory and experiment are in accord for the two-dimensional Ising system but features are still not understood in Heisenberg systems in both two and three dimensions
2. Wind turbine blade testing system using base excitation
Science.gov (United States)
Cotrell, Jason; Thresher, Robert; Lambert, Scott; Hughes, Scott; Johnson, Jay
2014-03-25
An apparatus (500) for fatigue testing elongate test articles (404) including wind turbine blades through forced or resonant excitation of the base (406) of the test articles (404). The apparatus (500) includes a testing platform or foundation (402). A blade support (410) is provided for retaining or supporting a base (406) of an elongate test article (404), and the blade support (410) is pivotally mounted on the testing platform (402) with at least two degrees of freedom of motion relative to the testing platform (402). An excitation input assembly (540) is interconnected with the blade support (410) and includes first and second actuators (444, 446, 541) that act to concurrently apply forces or loads to the blade support (410). The actuator forces are cyclically applied in first and second transverse directions. The test article (404) responds to shaking of its base (406) by oscillating in two, transverse directions (505, 507).
3. Wideband MEMS Resonator Using Multifrequency Excitation
KAUST Repository
Jaber, Nizar; Ramini, Abdallah; Al Hennawi, Qais M.; Younis, Mohammad I.
2016-01-01
We demonstrate the excitation of combination resonances of additive and subtractive types and their exploitations to realize a large bandwidth micro-machined resonator of large amplitude even at higher harmonic modes of vibrations. The investigation is conducted on a Microelectromechanical systems (MEMS) clamped-clamped microbeam fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from bottom. The microbeam is excited by a two-source harmonic excitation, where the first frequency source is swept around the targeted resonance (first or third mode of vibration) while the second source frequency is kept fixed. We report for the first time a large bandwidth and large amplitude response near the higher order modes of vibration. Also, we show that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled.
4. Wideband MEMS Resonator Using Multifrequency Excitation
KAUST Repository
Jaber, Nizar
2016-03-09
We demonstrate the excitation of combination resonances of additive and subtractive types and their exploitations to realize a large bandwidth micro-machined resonator of large amplitude even at higher harmonic modes of vibrations. The investigation is conducted on a Microelectromechanical systems (MEMS) clamped-clamped microbeam fabricated using polyimide as a structural layer coated with nickel from top and chromium and gold layers from bottom. The microbeam is excited by a two-source harmonic excitation, where the first frequency source is swept around the targeted resonance (first or third mode of vibration) while the second source frequency is kept fixed. We report for the first time a large bandwidth and large amplitude response near the higher order modes of vibration. Also, we show that by properly tuning the frequency and amplitude of the excitation force, the frequency bandwidth of the resonator is controlled.
5. Language identification using excitation source features
CERN Document Server
Rao, K Sreenivasa
2015-01-01
This book discusses the contribution of excitation source information in discriminating language. The authors focus on the excitation source component of speech for enhancement of language identification (LID) performance. Language specific features are extracted using two different modes: (i) Implicit processing of linear prediction (LP) residual and (ii) Explicit parameterization of linear prediction residual. The book discusses how in implicit processing approach, excitation source features are derived from LP residual, Hilbert envelope (magnitude) of LP residual and Phase of LP residual; and in explicit parameterization approach, LP residual signal is processed in spectral domain to extract the relevant language specific features. The authors further extract source features from these modes, which are combined for enhancing the performance of LID systems. The proposed excitation source features are also investigated for LID in background noisy environments. Each chapter of this book provides the motivatio...
6. Optimal placement of excitations and sensors for verification of large dynamical systems
Science.gov (United States)
Salama, M.; Rose, T.; Garba, J.
1987-01-01
The computationally difficult problem of the optimal placement of excitations and sensors to maximize the observed measurements is studied within the framework of combinatorial optimization, and is solved numerically using a variation of the simulated annealing heuristic algorithm. Results of numerical experiments including a square plate and a 960 degrees-of-freedom Control of Flexible Structure (COFS) truss structure, are presented. Though the algorithm produces suboptimal solutions, its generality and simplicity allow the treatment of complex dynamical systems which would otherwise be difficult to handle.
7. Energy-optimal electrical excitation of nerve fibers.
Science.gov (United States)
Jezernik, Saso; Morari, Manfred
2005-04-01
We derive, based on an analytical nerve membrane model and optimal control theory of dynamical systems, an energy-optimal stimulation current waveform for electrical excitation of nerve fibers. Optimal stimulation waveforms for nonleaky and leaky membranes are calculated. The case with a leaky membrane is a realistic case. Finally, we compare the waveforms and energies necessary for excitation of a leaky membrane in the case where the stimulation waveform is a square-wave current pulse, and in the case of energy-optimal stimulation. The optimal stimulation waveform is an exponentially rising waveform and necessitates considerably less energy to excite the nerve than a square-wave pulse (especially true for larger pulse durations). The described theoretical results can lead to drastically increased battery lifetime and/or decreased energy transmission requirements for implanted biomedical systems.
8. Coulomb excitation of {sup 8}Li
Energy Technology Data Exchange (ETDEWEB)
Assuncao, Marlete; Britos, Tatiane Nassar [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Ciencias Exatas e da Terra; Descouvemont, Pierre [Universite Libre de Bruxelles (ULB), Brussels (Belgium). Physique Nucleaire Theorique et Physique Mathematique; Lepine-Szily, Alinka; Lichtenthaler Filho, Rubens; Barioni, Adriana; Silva, Diego Medeiros da; Pereira, Dirceu; Mendes Junior, Djalma Rosa; Pires, Kelly Cristina Cezaretto; Gasques, Leandro Romero; Morais, Maria Carmen; Added, Nemitala; Neto Faria, Pedro; Rec, Rafael [Universidade de Sao Paulo (IF/USP), SP (Brazil). Inst. de Fisica. Dept. de Fisica Nuclear
2012-07-01
Full text: This work shows the Coulomb Excitation of {sup 8}Li on targets that have effectively behavior of Rutherford in angles and energies of interest for determining the value of the B(E2) electromagnetic transition. Theoretical aspects involved in this type of measure, known as COULEX [1], and some results in the literature [2-3] will be presented. Some problems with the targets and measurement system while performing an experiment on Coulomb Excitation of {sup 8}Li will be discussed: the energy resolution, background, possible contributions of the primary beam and also the excited states of the target near the region of elastic and inelastic peaks. They will be illustrated by measurements of the Coulomb Excitation of {sup 8}Li on targets of {sup 197}Au and {sup 208}Pb using the system RIBRAS(Brazilian Radioactive Ion Beam). In this case, the {sup 8}Li beam(T{sub 1/2} = 838 ms)is produced by {sup 9}Be({sup 7}Li;{sup 8} Li){sup 8}Be reaction from RIBRAS system which is installed at Instituto de Fisica of the Universidade de Sao Paulo. The primary {sup 7L}i beam is provided by Pelletron Accelerator. [1] K. Alder and A. Winther, Electromagnetic Excitation, North-Holland, New York, 1975; [2] P. Descouvemont and D. Baye, Phys. Letts. B 292, 235-238, 1992; [3] J. A. Brown, F. D. Becchetti, J. W. Jaenecke, K, Ashktorab, and D. A. Roberts, J. J. Kolata, R. J. Smith, and K. Lamkin, R. E. Warner, Phys. Rev. Letts., 66, 19, 1991; [4] R. J. Smith, J. J Kolata, K. Lamkin and A. Morsard, F. D. Becchetti, J. A. Brown, W. Z. Liu, J. W. Jaenecke, and D. A. Roberts, R. E. Warner, Phys. Rev. C, 43, 5, 1991. (author)
9. Nonlinear stability of spin-flip excitations
International Nuclear Information System (INIS)
Arunasalam, V.
1975-01-01
A rather complete discussion of the nonlinear electrodynamic behavior of a negative-temperature spin system is presented. The method presented here is based on a coupled set of master equations, one describing the time evolution of the photon (i.e., the spin-flip excitation) distribution function and the other describing the time evolution of the particle distribution function. It is found that the initially unstable (i.e., growing) spin-flip excitations grow to such a large amplitude that their nonlinear reaction on the particle distribution function becomes important. It is then shown that the initially totally inverted two-level spin system evolves rapidly (through this nonlinear photon-particle coupling) towards a quasilinear steady state where the populations of the spin-up and the spin-down states are equal to each other. Explicit expressions for the time taken to reach this quasilinear steady state and the energy in the spin-flip excitations at this state are also presented
10. A benchmark study of electronic excitation energies, transition moments, and excited-state energy gradients on the nicotine molecule
Energy Technology Data Exchange (ETDEWEB)
Egidi, Franco, E-mail: [email protected]; Segado, Mireia; Barone, Vincenzo, E-mail: [email protected] [Scuola Normale Superiore, Piazza dei Cavalieri, 7 I-56126 Pisa (Italy); Koch, Henrik [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Cappelli, Chiara [Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via G. Moruzzi, 3 I-56124 Pisa (Italy)
2014-12-14
In this work, we report a comparative study of computed excitation energies, oscillator strengths, and excited-state energy gradients of (S)-nicotine, chosen as a test case, using multireference methods, coupled cluster singles and doubles, and methods based on time-dependent density functional theory. This system was chosen because its apparent simplicity hides a complex electronic structure, as several different types of valence excitations are possible, including n-π{sup *}, π-π{sup *}, and charge-transfer states, and in order to simulate its spectrum it is necessary to describe all of them consistently well by the chosen method.
11. Light emitting diode excitation emission matrix fluorescence spectroscopy.
Science.gov (United States)
Hart, Sean J; JiJi, Renée D
2002-12-01
An excitation emission matrix (EEM) fluorescence instrument has been developed using a linear array of light emitting diodes (LED). The wavelengths covered extend from the upper UV through the visible spectrum: 370-640 nm. Using an LED array to excite fluorescence emission at multiple excitation wavelengths is a low-cost alternative to an expensive high power lamp and imaging spectrograph. The LED-EEM system is a departure from other EEM spectroscopy systems in that LEDs often have broad excitation ranges which may overlap with neighboring channels. The LED array can be considered a hybrid between a spectroscopic and sensor system, as the broad LED excitation range produces a partially selective optical measurement. The instrument has been tested and characterized using fluorescent dyes: limits of detection (LOD) for 9,10-bis(phenylethynyl)-anthracene and rhodamine B were in the mid parts-per-trillion range; detection limits for the other compounds were in the low parts-per-billion range (LED-EEMs were analyzed using parallel factor analysis (PARAFAC), which allowed the mathematical resolution of the individual contributions of the mono- and dianion fluorescein tautomers a priori. Correct identification and quantitation of six fluorescent dyes in two to six component mixtures (concentrations between 12.5 and 500 ppb) has been achieved with root mean squared errors of prediction (RMSEP) of less than 4.0 ppb for all components.
12. Comparison among nonlinear excitation control strategies used for damping power system oscillations
International Nuclear Information System (INIS)
Leon, A.E.; Solsona, J.A.; Valla, M.I.
2012-01-01
Highlights: ► A description and comparison of nonlinear control strategies for synchronous generators are presented. ► Advantages of using nonlinear controllers are emphasized against the use of classical PSSs. ► We find that a particular selection of IDA gains achieve the same performance that FL controllers. - Abstract: This work is focused on the problem of power system stability. A thorough description of nonlinear control strategies for synchronous generator excitation, which are designed for damping oscillations and improving transient stability on power systems, is presented along with a detailed comparison among these modern strategies and current solutions based on power system stabilizers. The performance related to damping injection in each controller, critical time enhancement, robustness against parametric uncertainties, and control signal energy consumption is analyzed. Several tests are presented to validate discussions on various advantages and disadvantages of each control strategy.
13. Exciter switch
Science.gov (United States)
Mcpeak, W. L.
1975-01-01
A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.
14. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection
OpenAIRE
Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian
2017-01-01
In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on ...
15. Terahertz Solitons in Biomolecular Systems and their Excitation by External Electromagnetic Field
Directory of Open Access Journals (Sweden)
Bugay А.N.
2015-01-01
Full Text Available Nonlinear dynamics of charge and acoustic excitations in cellular microtubules is considered. Different types of nonlinear solitary waves were studied taking account for dissipation. The mechanism of electro-acoustic pulse excitation by external electromagnetic field of terahertz frequency is recognized.
16. A high excitation magnetic quadrupole lens quadruplet incorporating a single octupole lens for a low spherical aberration probe forming lens system
Science.gov (United States)
Dou, Yanxin; Jamieson, David N.; Liu, Jianli; Li, Liyi
2018-03-01
This paper describes the design of a new probe forming lens system consisting of a high excitation magnetic quadrupole lens quadruplet that incorporates a single magnetic octupole lens. This system achieves both a high demagnification and a low spherical aberration compared to conventional high excitation systems and is intended for deployment for the Harbin 300 MeV proton microprobe for applications in space science and ion beam therapy. This relative simplicity of the ion optical design to include a single octupole lens minimizes the risks associated with the constructional and operational precision usually needed for the probe forming lens system and this system could also be deployed in microprobe systems that operate with less magnetically rigid ions. The design of the new system is validated with reference to two independent ion optical computer codes.
17. Autoresonant Excitation of Antiproton Plasmas
CERN Document Server
Andresen, Gorm B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Butler, Eoin; Carpenter, P T; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Hangst, Jeffrey S; Hardy, Walter N; Hayden, Michael E; Humphries, Andrew J; Hurt, J L; Hydomako, Richard; Jonsell, Svante; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wurtele, Jonathan S; Yamazaki, Yasunori
2011-01-01
We demonstrate controllable excitation of the center-of-mass longitudinal motion of a thermal antiproton plasma using a swept-frequency autoresonant drive. When the plasma is cold, dense, and highly collective in nature, we observe that the entire system behaves as a single-particle nonlinear oscillator, as predicted by a recent theory. In contrast, only a fraction of the antiprotons in a warm plasma can be similarly excited. Antihydrogen was produced and trapped by using this technique to drive antiprotons into a positron plasma, thereby initiating atomic recombination.
18. Modeling pulsed excitation for gas-phase laser diagnostics
International Nuclear Information System (INIS)
Settersten, Thomas B.; Linne, Mark A.
2002-01-01
Excitation dynamics for pulsed optical excitation are described with the density-matrix equations and the rate equations for a two-level system. A critical comparison of the two descriptions is made with complete and consistent formalisms that are amenable to the modeling of applied laser-diagnostic techniques. General solutions, resulting from numerical integration of the differential equations describing the excitation process, are compared for collisional conditions that range from the completely coherent limit to the steady-state limit, for which the two formalisms are identical. This analysis demonstrates the failure of the rate equations to correctly describe the transient details of the excitation process outside the steady-state limit. However, reasonable estimates of the resultant population are obtained for nonsaturating (linear) excitation. This comparison provides the laser diagnostician with the means to evaluate the appropriate model for excitation through a simple picture of the breakdown of the rate-equation validity
19. Clustered chimera states in systems of type-I excitability
International Nuclear Information System (INIS)
Vüllings, Andrea; Omelchenko, Iryna; Hövel, Philipp; Hizanidis, Johanne
2014-01-01
The chimera state is a fascinating phenomenon of coexisting synchronized and desynchronized behaviour that was discovered in networks of nonlocally coupled identical phase oscillators over ten years ago. Since then, chimeras have been found in numerous theoretical and experimental studies and more recently in models of neuronal dynamics as well. In this work, we consider a generic model for a saddle-node bifurcation on a limit cycle representative of neural excitability type I. We obtain chimera states with multiple coherent regions (clustered chimeras/multi-chimeras) depending on the distance from the excitability threshold, the range of nonlocal coupling and the coupling strength. A detailed stability diagram for these chimera states and other interesting coexisting patterns (like traveling waves) is presented. (paper)
20. Spectroscopy of collective excitations in interacting low-dimensional many-body systems using quench dynamics.
Science.gov (United States)
Gritsev, Vladimir; Demler, Eugene; Lukin, Mikhail; Polkovnikov, Anatoli
2007-11-16
We study the problem of rapid change of the interaction parameter (quench) in a many-body low-dimensional system. It is shown that, measuring the correlation functions after the quench, the information about a spectrum of collective excitations in a system can be obtained. This observation is supported by analysis of several integrable models and we argue that it is valid for nonintegrable models as well. Our conclusions are supplemented by performing exact numerical simulations on finite systems. We propose that measuring the power spectrum in a dynamically split 1D Bose-Einsten condensate into two coupled condensates can be used as an experimental test of our predictions.
1. Magnetic excitations in thulium metal
International Nuclear Information System (INIS)
Fernandez-Baca, J.A.; Nicklow, R.M.; Rhyne, J.J.
1989-01-01
We have performed inelastic neutron scattering measurements on a single crystal specimen of Tm at wavevectors rvec κ = (1,1, ζ) and (0,0,2 + ζ) (ζ = 0, hor-ellipsis, 1). Most of the measurements have been made at T = 5K, where Tm exhibits a seven layer ferrimagnetic-antiphase-domain structure (four moments up, parallel to the c-axis, followed by three moments down). At this temperature the excitation spectra consist of three peaks. The two lower energy excitations have been identified as originating from magneto-vibrational scattering from the TA phonon, while the higher energy excitation is magnetic and exhibits only a weak dispersion (between 8.3 and 9.6 meV). At T = 50K, a temperature at which the system exhibits a c-axis sinusoidally modulated structure, the magnetic mode shows significant softening and broadening. The magneto-vibrational scattering vanishes above the Neel temperature (T N = 58.5K) while the magnetic mode persists at least up to T = 70K. These results suggest that the Hamiltonian in this system is dominated by the crystal-field-anistropy energy, and that the exchange interaction is relatively weak. 9 refs., 2 figs
2. Relay protection coordination with generator capability curve, excitation system limiters and power system relay protections settings
Directory of Open Access Journals (Sweden)
Buha Danilo
2016-01-01
Full Text Available The relay protection settings performed in the largest thermal powerplant (TE "Nikola Tesla B" are reffered and explained in this paper. The first calculation step is related to the coordination of the maximum stator current limiter settings, the overcurrent protection with inverse characteristics settings and the permitted overload of the generator stator B1. In the second calculation step the settings of impedance generator protection are determined, and the methods and criteria according to which the calculations are done are described. Criteria used to provide the protection to fulfill the backup protection role in the event of malfunction of the main protection of the transmission system. are clarified. The calculation of all protection functions (32 functions of generator B1 were performed in the project "Coordination of relay protection blocks B1 and B2 with the system of excitation and power system protections -TENT B".
3. Seismic structural response analysis for multiple support excitation
International Nuclear Information System (INIS)
Shaw, D.E.
1975-01-01
In the seismic analysis of nuclear power plant equipment such as piping systems situations often arise in which piping systems span between adjacent structures or between different elevations in the same structure. Owing to the differences in the seismic time history response of different structures or different elevations of the same structure, the input support motion will differ for different supports. The concept of a frequency dependent participation factor and rotational response spectra accounting for phase differences between support excitations is developed by using classical equations of motion to formulate the seismic response of a structure subjected to multiple support excitation. The essence of the method lies in describing the seismic excitation of a multiply excited structure in terms of translational and rotational spectra used at every support and a frequency dependent spatial distribution function derived from the phase relationships of the different support time histories. In this manner it is shown that frequency dependent participation factors can be derived from the frequency dependent distribution functions. Examples are shown and discussed relative to closed form solutions and the state-of-the-art techniques presently being used for the solution of problems of multiply excited structures
4. Core excitation and de-excitation spectroscopies of free atoms and molecules
International Nuclear Information System (INIS)
Ueda, Kiyoshi
2006-01-01
This article provides a review of the current status of core excitation and de-excitation spectroscopy studies of free atoms molecules using a high-resolution soft X-ray monochromator and a high-resolution electron energy analyzer, installed in the soft X-ray photochemistry beam line at SPring-8. Experimental results are discussed for 1s excitation of Ne, O 1s excitation of CO and H 2 O, and F 1s excitation of CF 4 . (author)
5. Robust structural design against self-excited vibrations
CERN Document Server
Spelsberg-Korspeter, Gottfried
2013-01-01
This book studies methods for a robust design of rotors against self-excited vibrations. The occurrence of self-excited vibrations in engineering applications if often unwanted and in many cases difficult to model. Thinking of complex systems such as machines with many components and mechanical contacts, it is important to have guidelines for design so that the functionality is robust against small imperfections. This book discusses the question on how to design a structure such that unwanted self-excited vibrations do not occur. It shows theoretically and practically that the old design rule to avoid multiple eigenvalues points toward the right direction and have optimized structures accordingly. This extends results for the well-known flutter problem in which equations of motion with constant coefficients occur to the case of a linear conservative system with arbitrary time periodic perturbations.
6. Excited-state quantum phase transitions in systems with two degrees of freedom: II. Finite-size effects
Energy Technology Data Exchange (ETDEWEB)
Stránský, Pavel [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 18000 Prague (Czech Republic); Macek, Michal [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 18000 Prague (Czech Republic); Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06520-8120 (United States); Leviatan, Amiram [Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel); Cejnar, Pavel, E-mail: [email protected] [Institute of Particle and Nuclear Physics, Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 18000 Prague (Czech Republic)
2015-05-15
This article extends our previous analysis Stránský et al. (2014) of Excited-State Quantum Phase Transitions (ESQPTs) in systems of dimension two. We focus on the oscillatory component of the quantum state density in connection with ESQPT structures accompanying a first-order ground-state transition. It is shown that a separable (integrable) system can develop rather strong finite-size precursors of ESQPT expressed as singularities in the oscillatory component of the state density. The singularities originate in effectively 1-dimensional dynamics and in some cases appear in multiple replicas with increasing excitation energy. Using a specific model example, we demonstrate that these precursors are rather resistant to proliferation of chaotic dynamics. - Highlights: • Oscillatory components of state density and spectral flow studied near ESQPTs. • Enhanced finite-size precursors of ESQPT caused by fully/partly separable dynamics. • These precursors appear due to criticality of a subsystem with lower dimension. • Separability-induced finite-size effects disappear in case of fully chaotic dynamics.
7. From fusion hierarchy to excited state TBA
International Nuclear Information System (INIS)
Juettner, G.; Kluemper, A.
1998-01-01
Functional relations among the fusion hierarchy of quantum transfer matrices give a novel derivation of the TBA equations, namely without string hypothesis. This is demonstrated for two important models of 1D highly correlated electron systems, the supersymmetric t-J model and the supersymmetric extended Hubbard model. As a consequence, ''the excited state TBA'' equations, which characterize correlation lengths, are explicitly derived for the t-J model. To the authors' knowledge, this is the first explicit derivation of excited state TBA equations for 1D lattice electron systems. (orig.)
8. Doubly and triply excited states for different plasma sources
International Nuclear Information System (INIS)
More, R.M.; Safronova, U.I.
2000-01-01
Autoionizing rates of doubly excited states as nln'l' configurations with n=2-9 and n'=2-9 are calculated. Analytical expressions of decay amplitude for two-electron system are derived. Expressions for autoionizing rates with averaging over LS are obtained for many-electron systems. The n and l dependence of doubly excited states as nln'l' configurations are investigated. (author)
9. An Improved Multidimensional MPA Procedure for Bidirectional Earthquake Excitations
OpenAIRE
Wang, Feng; Sun, Jian-Gang; Zhang, Ning
2014-01-01
Presently, the modal pushover analysis procedure is extended to multidimensional analysis of structures subjected to multidimensional earthquake excitations. an improved multidimensional modal pushover analysis (IMMPA) method is presented in the paper in order to estimate the response demands of structures subjected to bidirectional earthquake excitations, in which the unidirectional earthquake excitation applied on equivalent SDOF system is replaced by the direct superposition of two compone...
10. Automatic vibration mode selection and excitation; combining modal filtering with autoresonance
Science.gov (United States)
Davis, Solomon; Bucher, Izhak
2018-02-01
Autoresonance is a well-known nonlinear feedback method used for automatically exciting a system at its natural frequency. Though highly effective in exciting single degree of freedom systems, in its simplest form it lacks a mechanism for choosing the mode of excitation when more than one is present. In this case a single mode will be automatically excited, but this mode cannot be chosen or changed. In this paper a new method for automatically exciting a general second-order system at any desired natural frequency using Autoresonance is proposed. The article begins by deriving a concise expression for the frequency of the limit cycle induced by an Autoresonance feedback loop enclosed on the system. The expression is based on modal decomposition, and provides valuable insight into the behavior of a system controlled in this way. With this expression, a method for selecting and exciting a desired mode naturally follows by combining Autoresonance with Modal Filtering. By taking various linear combinations of the sensor signals, by orthogonality one can "filter out" all the unwanted modes effectively. The desired mode's natural frequency is then automatically reflected in the limit cycle. In experiment the technique has proven extremely robust, even if the amplitude of the desired mode is significantly smaller than the others and the modal filters are greatly inaccurate.
11. Stochastic responses of Van der Pol vibro-impact system with fractional derivative damping excited by Gaussian white noise
Energy Technology Data Exchange (ETDEWEB)
Xiao, Yanwen; Xu, Wei, E-mail: [email protected]; Wang, Liang [Department of Applied Mathematics, Northwestern Polytechnical University, Xi' an 710072 (China)
2016-03-15
This paper focuses on the study of the stochastic Van der Pol vibro-impact system with fractional derivative damping under Gaussian white noise excitation. The equations of the original system are simplified by non-smooth transformation. For the simplified equation, the stochastic averaging approach is applied to solve it. Then, the fractional derivative damping term is facilitated by a numerical scheme, therewith the fourth-order Runge-Kutta method is used to obtain the numerical results. And the numerical simulation results fit the analytical solutions. Therefore, the proposed analytical means to study this system are proved to be feasible. In this context, the effects on the response stationary probability density functions (PDFs) caused by noise excitation, restitution condition, and fractional derivative damping are considered, in addition the stochastic P-bifurcation is also explored in this paper through varying the value of the coefficient of fractional derivative damping and the restitution coefficient. These system parameters not only influence the response PDFs of this system but also can cause the stochastic P-bifurcation.
12. Stochastic responses of Van der Pol vibro-impact system with fractional derivative damping excited by Gaussian white noise.
Science.gov (United States)
Xiao, Yanwen; Xu, Wei; Wang, Liang
2016-03-01
This paper focuses on the study of the stochastic Van der Pol vibro-impact system with fractional derivative damping under Gaussian white noise excitation. The equations of the original system are simplified by non-smooth transformation. For the simplified equation, the stochastic averaging approach is applied to solve it. Then, the fractional derivative damping term is facilitated by a numerical scheme, therewith the fourth-order Runge-Kutta method is used to obtain the numerical results. And the numerical simulation results fit the analytical solutions. Therefore, the proposed analytical means to study this system are proved to be feasible. In this context, the effects on the response stationary probability density functions (PDFs) caused by noise excitation, restitution condition, and fractional derivative damping are considered, in addition the stochastic P-bifurcation is also explored in this paper through varying the value of the coefficient of fractional derivative damping and the restitution coefficient. These system parameters not only influence the response PDFs of this system but also can cause the stochastic P-bifurcation.
13. Controlling flexible rotor vibrations using parametric excitation
Energy Technology Data Exchange (ETDEWEB)
Atepor, L, E-mail: [email protected] [Department of Mechanical Engineering, University of Glasgow, G12 8QQ (United Kingdom)
2009-08-01
This paper presents both theoretical and experimental studies of an active vibration controller for vibration in a flexible rotor system. The paper shows that the vibration amplitude can be modified by introducing an axial parametric excitation. The perturbation method of multiple scales is used to solve the equations of motion. The steady-state responses, with and without the parametric excitation terms, is investigated. An experimental test machine uses a piezoelectric exciter mounted on the end of the shaft. The results show a reduction in the rotor response amplitude under principal parametric resonance, and some good correlation between theory and experiment.
14. Relative excitation functions for singly-excited and core-excited levels of S V--S IX populated by the beam-foil interaction
International Nuclear Information System (INIS)
Moenke, D.; Bengtsson, P.; Engstroem, L.; Hutton, R.; Jupen, C.; Kirm, M.; Westerlind, M.
1994-01-01
We have investigated the relative excitation functions for low-lying singly excited and low-lying core-excited levels in S V (S 4+ ) to S IX (S 8+ ) after beam-foil excitation using ions in the energy range 2--10 MeV. The spectral line intensities have been normalized to the same number of particles at each ion energy and corrections for the level lifetimes have been made. The overall accuracy of the measured relative excitation function at each energy and charge state is estimated to be better than 2%. A comparison of the relative excitation functions for singly excited and core-excited lines shows a difference in S VII, but not in S VI
15. Measurement and analysis of excitation functions in 16O + 103Rh system in the excitation energy range ≅ 2-4 MeV/A
International Nuclear Information System (INIS)
Singh, Devendra P.; Unnati; Sharma, Manoj Kumar; Singh, Pushpendra P.; Singh, B.P.; Prasad, R.; Gupta, Sunita; Rakesh Kumar; Bhardwaj, H.D.
2006-01-01
In the present work, excitation functions for seven evaporation residues (ERs) produced via complete fusion and incomplete fusion processes in 16 O + 103 Rh system have been measured in the energy range ≅ 47-85 MeV, using recoil catcher technique followed by off-line gamma-ray spectrometry. Comparison of the experimental data with statistical model based computer code PACE 2 revealed dominance of incomplete fusion in reactions involving alpha-emission channels. To the best of our knowledge these reactions are being reported for the first time
Science.gov (United States)
Jansma, P. A.
1982-01-01
A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.
17. Low-frequency excitations in zirconium hydrides
International Nuclear Information System (INIS)
Radulescu, A.; Padureanu, I.; Rapeanu, S.N.; Beldiman, A.; Kozlov, Zh.A.; Semenov, V.A.
1999-01-01
The slow inelastic neutron scattering (INS) on ZrH x systems (x = 0.38, 0.52) revealed new excitations located within the energy range 2-10 MeV. Besides the acoustic vibrations specific to α-HCP Zr and γ-FCO Zr hydride the fine structure of these excitations is clearly observed. The origin of the new observed peaks is not very clear but a proton tunneling or a resonance effect in α-Zr lattice could be taken into account
18. Test and Control System for Chlorophyll Fluorescence Parameters Using LED as Excitation Source
Directory of Open Access Journals (Sweden)
Zou Qiuying
2014-05-01
Full Text Available A new scheme on test and control system for chlorophyll fluorescence is presented in this work, which uses light-emitting diode (LED excitation by means of measuring the fluorescence parameter fpsII. The system takes programmable power supply as LEDs illumination drive power with high sensitivity and signal-to-noise ratio. MINIPAM is used to measure fluorescence parameter fpsII and keeps communication with upper PC by serial port. The upper PC can control the power supply and process the data received from MINIPAM by software which is programmed in VB6. The results show that the system has a lot of advantages such as high accuracy and convenience. The effect of environmental factors on fluorescence parameters is analyzed comprehensively. It will be a practical measurement and control system for photosynthetic ability and have wide application foreground.
19. Magnetic measurement of soft magnetic composites material under 3D SVPWM excitation
Science.gov (United States)
Zhang, Changgeng; Jiang, Baolin; Li, Yongjian; Yang, Qingxin
2018-05-01
The magnetic properties measurement and analysis of soft magnetic material under the rotational space-vector pulse width modulation (SVPWM) excitation are key factors in design and optimization of the adjustable speed motor. In this paper, a three-dimensional (3D) magnetic properties testing system fit for SVPWM excitation is built, which includes symmetrical orthogonal excitation magnetic circuit and cubic field-metric sensor. Base on the testing system, the vector B and H loci of soft magnetic composite (SMC) material under SVPWM excitation are measured and analyzed by proposed 3D SVPWM control method. Alternating and rotating core losses under various complex excitation with different magnitude modulation ratio are calculated and compared.
20. Stochastic stability of mechanical systems under renewal jump process parametric excitation
DEFF Research Database (Denmark)
Iwankiewicz, R.; Nielsen, Søren R.K.; Larsen, Jesper Winther
2005-01-01
independent, negative exponential distributed variables; hence, the arrival process may be termed as a generalized Erlang renewal process. The excitation process is governed by the stochastic equation driven by two independent Poisson processes, with different parameters. If the response in a single mode...... is investigated, the problem is governed in the state space by two stochastic equations, because the stochastic equation for the excitation process is autonomic. However due to the parametric nature of the excitation, the nonlinear term appears at the right-hand sides of the equations. The equations become linear...... of the stochastic equation governing the natural logarithm of the hyperspherical amplitude process and using the modification of the method wherein the time averaging of the pertinent expressions is replaced by ensemble averaging. It is found that the direct simulation is more suitable and that the asymptotic mean...
1. Mechanism of spiral formation in heterogeneous discretized excitable media.
Science.gov (United States)
Kinoshita, Shu-ichi; Iwamoto, Mayuko; Tateishi, Keita; Suematsu, Nobuhiko J; Ueyama, Daishin
2013-06-01
Spiral waves on excitable media strongly influence the functions of living systems in both a positive and negative way. The spiral formation mechanism has thus been one of the major themes in the field of reaction-diffusion systems. Although the widely believed origin of spiral waves is the interaction of traveling waves, the heterogeneity of an excitable medium has recently been suggested as a probable cause. We suggest one possible origin of spiral waves using a Belousov-Zhabotinsky reaction and a discretized FitzHugh-Nagumo model. The heterogeneity of the reaction field is shown to stochastically generate unidirectional sites, which can induce spiral waves. Furthermore, we found that the spiral wave vanished with only a small reduction in the excitability of the reaction field. These results reveal a gentle approach for controlling the appearance of a spiral wave on an excitable medium.
2. Examination of excited state populations in sputtering using Multiphoton Resonance Ionization
International Nuclear Information System (INIS)
Kimock, F.M.; Baxter, J.P.; Pappas, D.L.; Kobrin, P.H.; Winograd, N.
1984-01-01
Multiphoton Resonance Ionization has been employed to study the populations of excited state atoms ejected from ion bombarded metal surfaces. Preliminary investigations have focused on three model systems: aluminum, indium and cobalt. In this paper the authors examine the effect of primary ion energy (2 to 12 keV Ar + ) on excited state yields for these three systems. The influence of the sample matrix on excited state populations of sputtered atoms is also discussed
3. Photoinduced Ultrafast Intramolecular Excited-State Energy Transfer in the Silylene-Bridged Biphenyl and Stilbene (SBS) System: A Nonadiabatic Dynamics Point of View.
Science.gov (United States)
Wang, Jun; Huang, Jing; Du, Likai; Lan, Zhenggang
2015-07-09
The photoinduced intramolecular excited-state energy-transfer (EET) process in conjugated polymers has received a great deal of research interest because of its important role in the light harvesting and energy transport of organic photovoltaic materials in photoelectric devices. In this work, the silylene-bridged biphenyl and stilbene (SBS) system was chosen as a simplified model system to obtain physical insight into the photoinduced intramolecular energy transfer between the different building units of the SBS copolymer. In the SBS system, the vinylbiphenyl and vinylstilbene moieties serve as the donor (D) unit and the acceptor (A) unit, respectively. The ultrafast excited-state dynamics of the SBS system was investigated from the point of view of nonadiabatic dynamics with the surface-hopping method at the TDDFT level. The first two excited states (S1 and S2) are characterized by local excitations at the acceptor (vinylstilbene) and donor (vinylbiphenyl) units, respectively. Ultrafast S2-S1 decay is responsible for the intramolecular D-A excitonic energy transfer. The geometric distortion of the D moiety play an essential role in this EET process, whereas the A moiety remains unchanged during the nonadiabatic dynamics simulation. The present work provides a direct dynamical approach to understand the ultrafast intramolecular energy-transfer dynamics in SBS copolymers and other similar organic photovoltaic copolymers.
4. Piping damping tests evaluating influence of types of support and excitation
International Nuclear Information System (INIS)
Arendts, J.G.; Ware, A.G.; Gorman, V.W.
1985-01-01
The United States Nuclear Regulatory Commission and the Electric Power Research Institute have jointly sponsored construction of two laboratory piping systems at the ANCO Engineers facility in California. EG and G Idaho used the second of these systems to obtain piping system damping data using different supports and methods of excitation. The 6-in. carbon steel piping system was approximately 50 ft in length with two 3-in. branch lines. It was supported at five locations and excited using a single electrohydraulic shaker. Both random and swept sine methods of excitations were used. A variable support attached near the shaker location allowed four different configurations to be tested: a rigid strut, a mechanical snubber, a hydraulic snubber, and a rigid strut with a gap. Data were recorded for the lowest nine significant modes. Damping for the first three modes ranged for 1 to 3% of critical damping and decreased as frequency increased. The random excitation produced a slightly higher average overall damping of the system
5. Design considerations for highly effective fluorescence excitation and detection optical systems for molecular diagnostics
Science.gov (United States)
Kasper, Axel; Van Hille, Herbert; Kuk, Sola
2018-02-01
Modern instruments for molecular diagnostics are continuously optimized for diagnostic accuracy, versatility and throughput. The latest progress in LED technology together with tailored optics solutions allows developing highly efficient photonics engines perfectly adapted to the sample under test. Super-bright chip-on-board LED light sources are a key component for such instruments providing maximum luminous intensities in a multitude of narrow spectral bands. In particular the combination of white LEDs with other narrow band LEDs allows achieving optimum efficiency outperforming traditional Xenon light sources in terms of energy consumption, heat dissipation in the system, and switching time between spectral channels. Maximum sensitivity of the diagnostic system can only be achieved with an optimized optics system for the illumination and imaging of the sample. The illumination beam path must be designed for optimum homogeneity across the field while precisely limiting the angular distribution of the excitation light. This is a necessity for avoiding spill-over to the detection beam path and guaranteeing the efficiency of the spectral filtering. The imaging optics must combine high spatial resolution, high light collection efficiency and optimized suppression of excitation light for good signal-to-noise ratio. In order to achieve minimum cross-talk between individual wells in the sample, the optics design must also consider the generation of stray light and the formation of ghost images. We discuss what parameters and limitations have to be considered in an integrated system design approach covering the full path from the light source to the detector.
6. Kinetics of excited levels in copper-vapor laser
International Nuclear Information System (INIS)
Smilanski, I.
1981-10-01
A full and representative description of the excited copper level kinetics in a copper-vapor laser is presented. The research was carried out in three stages. The first stage was the development of a representative and reliable measurement cell. A laser tube constructed of refractory materials and an excitation circuit which provides short pulses at a high repetition rate to heat the tube and excite the copper atoms were developed. This stage was also dedicated to characterizing the laser and studying its scaling laws. In the second stage a rapid neasuring system which avoids the problem of spectral line shape was developed. The system is based on the 'hook' method, which utilizes the anomalous dispersion in the vicinity of an atomic line. The light source, a wide band nitrogen-laser-pumped dye laser, ensures a short sampling time, and the recording system, with a television camera face as the recording medium, allows precise data reduction. In the third stage the excited copper level kinetics in a copper vapor laser is measured. The principal conclusions, that only a small part of the energy in the discharge is utilized to populate the upper laser levels and that the lower laser level population is very large at the end of the excitation pulse and cannot be attributed to relaxation of the upper levels, necessitate a new kinetic description of the copper-vapor laser. The laser is not self-terminating; it is activated and terminated by the electrical discharge
7. Validations of CNDOL approximate Hamiltonian as a fast and reliable method to obtain vertical excitation energies in polyatomic systems
International Nuclear Information System (INIS)
Montero-Alejo, Ana L.; Gonzalez-Santana, Susana; Montero-Cabrera, Luis A.; Hernandez-Rodriguez, Erix Wiliam; Fuentes-Montero, Maria Elena; Bunge-Molina, Carlos F.; Gonzalez, Augusto
2008-01-01
Theoretical prediction of vertical excitation energies and an estimation of charge distributions of polyatomic systems can be calculated, through the configuration interaction of single (CIS) excited determinants procedure, with the CNDOL (Complete Neglect of Differential Overlap considering the l azimuthal quantum number) Hamiltonians. This method does not use adjusted parameters to fit experimental data and only employ a priori data on atomic orbitals and simple formulas to substitute large computations of electronic integrals. In this sense, different functions for bi-electron integrals have been evaluated in order to improve the approximate Hamiltonian. The reliability of predictions and theoretical consistence has been tested with a benchmark set of organic molecules that covers important classes of chromophores including polyenes and other unsaturated aliphatic compounds, aromatic, hydrocarbons, heterocycles, carbonyl compounds, and nucleobases. The calculations are done at identical geometries (MP2) with the same basis set (6-31G) for these medium-sized molecules and the obtained results were statistically compared with other analogous methods and experimental data. The accuracy of prediction of each CNDOL vertical transitions energy increases while the active space is more complete allowing the best variational optimization of CIS matrices i.e. molecular excited states. Moreover and due to the feasible computation procedure for large polyatomic systems, the studies have been extended, as a preliminary work, in the field of optoelectronic materials for photovoltaic applications. Hence, the excitation energies of different conjugated Phenyl-cored Thiophene Dendrimers optimized by DFT (Density Functional Theory) were calculated and show good agreement with the experiment data. The predicted charge distribution during the excitation contributes to understand the photophysics process on these kind materials. (Full text)
8. Design and Implementation of Wideband Exciter for an Ultra-high Resolution Airborne SAR System
Directory of Open Access Journals (Sweden)
Jia Ying-xin
2013-03-01
Full Text Available According to an ultra-high resolution airborne SAR system with better than 0.1 m resolution, a wideband Linear Frequency Modulated (LFM pulse compression exciter with 14.8 GHz carrier and 3.2 GHz bandwidth is designed and implemented. The selection of signal generation scheme and some key technique points for wideband LFM waveform is presented in detail. Then, an acute test and analysis of the LFM signal is performed. The final airborne experiments demonstrate the validity of the LFM source which is one of the subsystems in an ultra-high resolution airborne SAR system.
9. Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation
International Nuclear Information System (INIS)
Wibowo,; Zakaria,; Lambang, Lullus; Triyono,; Muhayat, Nurul
2016-01-01
The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.
10. Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation
Energy Technology Data Exchange (ETDEWEB)
Wibowo,, E-mail: [email protected]; Zakaria,, E-mail: [email protected]; Lambang, Lullus, E-mail: [email protected]; Triyono,, E-mail: [email protected]; Muhayat, Nurul, E-mail: [email protected] [Mechanical Engineering Department, Sebelas Maret University, Surakarta 57128 (Indonesia)
2016-03-29
The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.
11. Approximate Forward Difference Equations for the Lower Order Non-Stationary Statistics of Geometrically Non-Linear Systems subject to Random Excitation
DEFF Research Database (Denmark)
Köylüoglu, H. U.; Nielsen, Søren R. K.; Cakmak, A. S.
Geometrically non-linear multi-degree-of-freedom (MDOF) systems subject to random excitation are considered. New semi-analytical approximate forward difference equations for the lower order non-stationary statistical moments of the response are derived from the stochastic differential equations...... of motion, and, the accuracy of these equations is numerically investigated. For stationary excitations, the proposed method computes the stationary statistical moments of the response from the solution of non-linear algebraic equations....
12. Examination of excited state populations in sputtering using multiphoton resonance ionization
International Nuclear Information System (INIS)
Kimock, F.M.; Baxter, J.P.; Pappas, D.L.; Kobrin, P.H.; Winograd, N.
1984-01-01
Multiphoton Resonance Ionization has been employed to study the populations of excited state atoms ejected from ion bombarded metal surfaces. Preliminary investigations have focused on three model systems: aluminum, indium and cobalt. In this paper we examine the effect of primary ion energy (2 to 12 keV Ar + ) on excited state yields for these three systems. The influence of the sample matrix on excited state populations of sputtered atoms is also discussed. 8 refs., 4 figs
13. Magnetic excitations in low-dimensional spin systems: neutron scattering study on AV2O5
International Nuclear Information System (INIS)
Nakajima, Kenji
1997-01-01
Recent experiments on vanadium oxide bronzes AV 2 O 5 (A=Na, Mg, Li) are reviewed. Experiments are carried out combining two triple-axis spectrometers installed at a thermal beam port and a cold neutron guide at JRR-3M. Spin-wave excitations in single crystals NaV 2 O 5 in the spin-Peierls state shows a steep intra-chain dispersion, which is consistent with estimated exchange interaction from magnetization measurement, and a weak inter-chain dispersion. In the low energy excitation measurement on powder sample of MgV 2 O 5 , we have observed energy gap of 2 meV, which indicates that this material is a ladder system with strong 1D character. Preliminary result on LiV 2 O 5 , which is expected to be a simple 1D antiferromagnet or a zig-zag chain, is also mentioned
14. Surface and bulk excitations in condensed matter
International Nuclear Information System (INIS)
Ritchie, R.H.
1988-01-01
In this lecture collective and single-particle electron excitations of solids will be discussed with emphasis on the properties of metallic and semiconducting materials. However, some of the general properties of long-wavelength collective modes to be discussed are valid for insulators as well, and some considerations apply to nuclear excitations such as optical or acoustical phonons, dipolar plasmons, etc. The concept of elementary excitations in solids, pioneered by Bohm and Pines almost 4 decades ago, has proved to be extremely useful in understanding the properties of systems of many particles, especially in respect to the response to the action of external probes. 32 refs., 12 figs
15. Excitations of Bose-Einstein condensates at finite temperatures
International Nuclear Information System (INIS)
Rusch, M.
2000-01-01
Recent experimental observations of collective excitations of Bose condensed atomic vapours have stimulated interest in the microscopic description of the dynamics of a Bose-Einstein condensate confined in an external potential. We present a finite temperature field theory for collective excitations of trapped Bose-Einstein condensates and use a finite-temperature linear response formalism, which goes beyond the simple mean-field approximation of the Gross-Pitaevskii equation. The effect of the non-condensed thermal atoms we include using perturbation theory in a quasiparticle basis. This presents a simple scheme to understand the interaction between condensate and non-condensed atoms and enables us to include the effect the condensate has on collision dynamics. At first we limit our treatment to the case of a spatially homogeneous Bose gas. We include the effect of pair and triplet anomalous averages and thus obtain a gapless theory for the excitations of a weakly interacting system, which we can link to well known results for Landau and Beliaev damping rates. A gapless theory for trapped systems with a static thermal component follows straightforwardly. We then investigate finite temperature excitations of a condensate in a spherically symmetric harmonic trap. We avoid approximations to the density of states and thus emphasise finite size aspects of the problem. We show that excitations couple strongly to a restricted number of modes, giving rise to resonance structure in their frequency spectra. Where possible we derive energy shifts and lifetimes of excitations. For one particular mode, the breathing mode, the effects of the discreteness of the system are sufficiently pronounced that the simple picture of an energy shift and width fails. Experiments in spherical traps have recently become feasible and should be able to test our detailed quantitative predictions. (author)
16. Resonantly enhanced production of excited fragments of gaseous molecules following core-level excitation
International Nuclear Information System (INIS)
Chen, J.M.; Lu, K.T.; Lee, J.M.; Ho, S.C.; Chang, H.W.; Lee, Y.Y.
2005-01-01
State-selective dissociation dynamics for the excited fragments of gaseous Si(CH 3 ) 2 Cl 2 following Cl 2p and Si 2p core-level excitations have been investigated by resonant photoemission spectroscopy and dispersed UV/optical fluorescence spectroscopy. The main features in the gaseous Si(CH 3 ) 2 Cl 2 fluorescence spectrum are identified as the emission from excited Si*, Si + *, CH* and H*. The core-to-Rydberg excitations at both Si 2p and Cl 2p edges lead to a noteworthy production of not only the excited atomic fragments, neutral and ionic (Si*, Si + *) but also the excited diatomic fragments (CH*). In particular, the excited neutral atomic fragments Si* are significantly reinforced. The experimental results provide deeper insight into the state-selective dissociation dynamics for the excited fragments of molecules via core-level excitation
17. Development of tunable flashlamp excited dye laser system
International Nuclear Information System (INIS)
Bhanthumnavin, V.; Apikitmata, S.; Kochareon, P.
1991-01-01
A tunable flashlamp excited dye laser (FEDL) was successfully developed for the first time in Thailand by Thai scientists at KMIT Thonburi (Bangmod). The Rhodamine 6G dissolved in ethyl alcohol was utilized as a laser medium and circulated by a pump through a laser head. The dye cuvette had an inner diameter of 4.0 mm and was 90 mm long. The cavity mirrors M 1 , and M 2 were concave mirrors with reflectivities of 100% and 73% respectively. A power supply of 0-20 kV and current of 0-50 mA charged a capacitor of 0.3 μ f at 10-15 kV which was then discharged via a spark gap through the flashlamp. The output laser wavelengths was tunable from λ = 550-640 nm. It is the first FEDL system, locally developed, which has a tunable wavelength for the laser output. The laser pulse width is about 1.0 μs with energy of 20 mJ and peak power pf 20 KW. The repetition rate of the laser is 1/15 Hz. (author). 14 refs, 7 figs
18. Generation of spiral waves pinned to obstacles in a simulated excitable system
Science.gov (United States)
Phantu, Metinee; Kumchaiseemak, Nakorn; Porjai, Porramain; Sutthiopad, Malee; Müller, Stefan C.; Luengviriya, Chaiya; Luengviriya, Jiraporn
2017-09-01
Pinning phenomena emerge in many dynamical systems. They are found to stabilize extreme conditions such as superconductivity and super fluidity. The dynamics of pinned spiral waves, whose tips trace the boundary of obstacles, also play an important role in the human health. In heart, such pinned waves cause longer tachycardia. In this article, we present two methods for generating pinned spiral waves in a simulated excitable system. In method A, an obstacle is set in the system prior to an ignition of a spiral wave. This method may be suitable only for the case of large obstacles since it often fails when used for small obstacles. In method B, a spiral wave is generated before an obstacle is placed at the spiral tip. With this method, a pinned spiral wave is always obtained, regardless the obstacle size. We demonstrate that after a transient interval the dynamics of the pinned spiral waves generated by the methods A and B are identical. The initiation of pinned spiral waves in both two- and three-dimensional systems is illustrated.
19. Observation and quantification of the quantum dynamics of a strong-field excited multi-level system.
Science.gov (United States)
Liu, Zuoye; Wang, Quanjun; Ding, Jingjie; Cavaletto, Stefano M; Pfeifer, Thomas; Hu, Bitao
2017-01-04
The quantum dynamics of a V-type three-level system, whose two resonances are first excited by a weak probe pulse and subsequently modified by another strong one, is studied. The quantum dynamics of the multi-level system is closely related to the absorption spectrum of the transmitted probe pulse and its modification manifests itself as a modulation of the absorption line shape. Applying the dipole-control model, the modulation induced by the second strong pulse to the system's dynamics is quantified by eight intensity-dependent parameters, describing the self and inter-state contributions. The present study opens the route to control the quantum dynamics of multi-level systems and to quantify the quantum-control process.
20. Nonlinear excitations in biomolecules
International Nuclear Information System (INIS)
Peyrard, M.
1995-01-01
The aim of the workshop entitled ''Nonlinear Excitations in Biomolecules'' is to attempt to bridge the gap between the physicists and biologists communities which is mainly due to language and cultural barriers. The progress of nonlinear science in the last few decades which have shown that the combination of nonlinearity, which characterize most biological phenomena, and cooperative effects in a system having a large number of degrees of freedom, can give rise to coherent excitations with remarkable properties. New concepts, such as solitons nd nonlinear energy localisation have become familiar to physicists and applied mathematicians. It is thus tempting to make an analogy between these coherent excitations and the exceptional stability of some biological processes, such as for instance DNA transcription, which require the coordination of many events in the ever changing environment of a cell. Physicists are now invoking nonlinear excitations to describe and explain many bio-molecular processes while biologists often doubt that the seemingly infinite variety of phenomena that they are attempting to classify can be reduced to such simple concepts. A large part of the meeting is devoted to tutorial lectures rather than to latest research results. The book provides a pedagogical introduction to the two topics forming the backbone of the meeting: the theory of nonlinear excitations and solitons, and their application in biology; and the structure and function of biomolecules, as well as energy and charge transport in biophysics. In order to emphasize the link between physics and biology, the volume is not divided along these two topics but according to biological subjects. Each chapter starts with a short introduction attempting to help the reader to find his way among the contributions and point out the connection between them. 23 lectures over the 32 presented have been selected and refers to quantum properties of macro-molecules. (J.S.)
1. Dissociative Excitation of Thymine by Electron Impact
Science.gov (United States)
McConkey, William; Tiessen, Collin; Hein, Jeffrey; Trocchi, Joshuah; Kedzierski, Wladek
2014-05-01
A crossed electron-gas beam system coupled to a VUV spectrometer has been used to investigate the dissociation of thymine (C5H6N2O2) into excited atomic fragments in the electron-impact energy range from threshold to 375 eV. A special stainless steel oven is used to vaporize the thymine and form it into a beam where it is intersected by a magnetically collimated electron beam, typical current 50 μA. The main features in the spectrum are the H Lyman series lines. The probability of extracting excited C or N atoms from the ring is shown to be very small. In addition to spectral data, excitation probability curves as a function of electron energy will be presented for the main emission features. Possible dissociation channels and excitation mechanisms in the parent molecule will be discussed. The authors thank NSERC (Canada) for financial support.
2. Excitation function of elastic scattering on 12C + 4He system, at low energies
International Nuclear Information System (INIS)
Perez-Torres, R.; Aguilera, E. F.; Martinez-Quiroz, E.; Murillo, G.; Belyaeva, T. L.; Maldonado-Velazquez, M.
2011-01-01
Interactions in the 12 C + 4 He system are of great interest in astrophysics and to help determine the relative abundances of elements in stars, at the end of helium burning [1, 2]. The Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico, have made measurements of elastic scattering for this system, using the inverse kinematics method with thick white gas [3, 4], for E CM (0.5 - 4 MeV) θ CM = 180 o . In this work we obtain excitation functions of elastic scattering of 12 C + 4 He system with angular and energy dependence; E CM = 0.5 - 4 MeV and θ CM 100 o -170 o .Using inverse kinematics method with thick white gas and energy loss tables. (Author)
3. Self-excitation of single nanomechanical pillars
Science.gov (United States)
Kim, Hyun S.; Qin, Hua; Blick, Robert H.
2010-03-01
Self-excitation is a mechanism that is ubiquitous for electromechanical power devices such as electrical generators. This is conventionally achieved by making use of the magnetic field component in electrical generators (Nedic and Lipo 2000 IEEE/IAS Conf. Records (Rome, Italy) vol 1 pp 51-6), a good and widely visible example of which is the wind turbine farm (Muljadi et al 2005 J. Sol. Energy Eng. 127 581-7). In other words, a static force, such as the wind acting on rotor blades, can generate a resonant excitation at a certain mechanical frequency. For nanomechanical systems (Craighead 2000 Science 290 1532-5 Roukes 2001 Phys. World 14 25-31 Cleland 2003 Foundations of Nanomechanics (Berlin: Springer); Ayari et al 2007 Nano Lett. 7 2252-7 Koenig et al 2008 Nat. Nanotechnol. 3 482-4) such a self-excitation (SE) mechanism is also highly desirable, because it can generate mechanical oscillations at radio frequencies by simply applying a dc bias voltage. This is of great importance for low-power signal communication devices and detectors, as well as for mechanical computing elements. For a particular nanomechanical system—the single electron shuttle—this effect was predicted some time ago by Gorelik et al (Phys. Rev. Lett. 80 4526-9). Here, we use a nanoelectromechanical single electron transistor (NEMSET) to demonstrate self-excitation for both the soft and hard regimes, respectively. The ability to use self-excitation in nanomechanical systems may enable the detection of quantum mechanical backaction effects (Naik et al 2006 Nature 443 193-6) in direct tunneling, macroscopic quantum tunneling (Savelev et al 2006 New J. Phys. 8 105-15) and rectification (Pistolesi and Fazio 2005 Phys. Rev. Lett. 94 036806-4). All these effects have so far been overshadowed by the large driving voltages that had to be applied.
4. Microstructure ion Nuclear Spectra at High Excitation
International Nuclear Information System (INIS)
Ericson, T.E.O.
1969-01-01
The statistical microstructure of highly excited systems is illustrated by the distribution and fluctuations of levels, widths and cross-sections of nuclei both for the case of sharp resonances and the continuum case. The coexistence of simple modes of excitation with statistical effects in terms of strength functions is illustrated by isobaric analogue states. The analogy is made with similar phenomena for coherent light, is solid-state physics and high-energy physics. (author)
5. Stationary responses of a Rayleigh viscoelastic system with zero barrier impacts under external random excitation.
Science.gov (United States)
Wang, Deli; Xu, Wei; Zhao, Xiangrong
2016-03-01
This paper aims to deal with the stationary responses of a Rayleigh viscoelastic system with zero barrier impacts under external random excitation. First, the original stochastic viscoelastic system is converted to an equivalent stochastic system without viscoelastic terms by approximately adding the equivalent stiffness and damping. Relying on the means of non-smooth transformation of state variables, the above system is replaced by a new system without an impact term. Then, the stationary probability density functions of the system are observed analytically through stochastic averaging method. By considering the effects of the biquadratic nonlinear damping coefficient and the noise intensity on the system responses, the effectiveness of the theoretical method is tested by comparing the analytical results with those generated from Monte Carlo simulations. Additionally, it does deserve attention that some system parameters can induce the occurrence of stochastic P-bifurcation.
6. Multiflavour excited mesons from the fifth dimension
International Nuclear Information System (INIS)
Paredes, Angel; Talavera, Pere
2005-01-01
We study the Regge trajectories and the quark-antiquark energy in excited hadrons composed by different dynamical mass constituents via the gauge/string correspondence. First we exemplify the procedure in a supersymmetric system, D3-D7, in the extremal case. Afterwards we discuss the model dual to large-N c QCD, D4-D6 system. In the latter case we find the field theory expected gross features of vector like theories: the spectrum resembles that of heavy quarkonia and the Chew-Frautschi plot of the singlet and first excited states is in qualitative agreement with those of lattice QCD. We stress the salient points of including different constituents masses
7. Immersion and Invariance-Based Coordinated Generator Excitation and SVC Control for Power Systems
Directory of Open Access Journals (Sweden)
2014-01-01
Full Text Available A nonlinear coordinated control of excitation and SVC of an electrical power system is proposed for transient stability, and voltage regulation enhancement after the occurrence of a large disturbance and a small perturbation. Using the concept of Immersion and Invariance (I&I design methodology, the proposed nonlinear controller is used to not only achieve power angle stability, frequency and voltage regulation but also ensure that the closed-loop system is transiently and asymptotically stable. In order to show the effectiveness of the proposed controller design, the simulation results illustrate that, in spite of the case where a large perturbation occurs on the transmission line or there is a small perturbation to mechanical power inputs, the proposed controller can not only keep the system transiently stable but also simultaneously accomplish better dynamic properties of the system as compared to operation with the existing controllers designed through a coordinated passivation technique controller and a feedback linearization scheme, respectively.
8. Design and development of a parametrically excited nonlinear energy harvester
International Nuclear Information System (INIS)
Yildirim, Tanju; Ghayesh, Mergen H.; Li, Weihua; Alici, Gursel
2016-01-01
Highlights: • A parametrically broadband energy harvester was fabricated. • Strong softening-type nonlinear behaviour was observed. • Experiments were conducted showing the large bandwidth of the device. - Abstract: An energy harvester has been designed, fabricated and tested based on the nonlinear dynamical response of a parametrically excited clamped-clamped beam with a central point-mass; magnets have been used as the central point-mass which pass through a coil when parametrically excited. Experiments have been conducted for the energy harvester when the system is excited (i) harmonically near the primary resonance; (ii) harmonically near the principal parametric resonance; (iii) by means of a non-smooth periodic excitation. An electrodynamic shaker was used to parametrically excite the system and the corresponding displacement of the magnet and output voltages of the coil were measured. It has been shown that the system displays linear behaviour at the primary resonance; however, at the principal parametric resonance, the motion characteristic of the magnet substantially changed displaying a strong softening-type nonlinearity. Theoretical simulations have also been conducted in order to verify the experimental results; the comparison between theory and experiment were within very good agreement of each other. The energy harvester developed in this paper is capable of harvesting energy close to the primary resonance as well as the principal parametric resonance; the frequency-band has been broadened significantly mainly due to the nonlinear effects as well as the parametric excitation.
9. Excited states 2
CERN Document Server
Lim, Edward C
2013-01-01
Excited States, Volume 2 is a collection of papers that deals with molecules in the excited states. The book describes the geometries of molecules in the excited electronic states. One paper describes the geometries of a diatomic molecule and of polyatomic molecules; it also discusses the determination of the many excited state geometries of molecules with two, three, or four atoms by techniques similar to diatomic spectroscopy. Another paper introduces an ordered theory related to excitons in pure and mixed molecular crystals. This paper also presents some experimental data such as those invo
10. Flow-excited acoustic resonance excitation mechanism, design guidelines, and counter measures
International Nuclear Information System (INIS)
2014-01-01
The excitation mechanism of acoustic resonances has long been recognized, but the industry continues to be plagued by its undesirable consequences, manifested in severe vibration and noise problems in a wide range of industrial applications. This paper focuses on the nature of the excitation mechanism of acoustic resonances in piping systems containing impinging shear flows, such as flow over shallow and deep cavities. Since this feedback mechanism is caused by the coupling between acoustic resonators and shear flow instabilities, attention is focused first on the nature of various types of acoustic resonance modes and then on the aero-acoustic sound sources, which result from the interaction of the inherently unstable shear flow with the sound field generated by the resonant acoustic modes. Various flow-sound interaction patterns are discussed, in which the resonant sound field can be predominantly parallel or normal to the mean flow direction and the acoustic wavelength can be an order of magnitude longer than the length scale of the separated shear flow or as short as the cavity length scale. Since the state of knowledge in this field has been recently reviewed by Tonon et al. (2011, 'Aero-acoustics of Pipe Systems With Closed Branches', Int. J. Aeroacoust., 10(2), pp. 201-276), this article focuses on the more practical aspects of the phenomenon, including various flow sound interaction patterns and the resulting aero-acoustic sources, which are relevant to industrial applications. A general design guide proposal and practical means to alleviate the excitation mechanism are also presented. These are demonstrated by two examples of recent industrial case histories dealing with acoustic fatigue failure of the steam dryer in a boiling water reactor (BWR) due to acoustic resonance in the main steam piping and acoustic resonances in the roll posts of the Short Take-Off and Vertical Lift Joint Strike Fighter (JSF). (authors)
11. Nerve conduction and excitability studies in peripheral nerve disorders
DEFF Research Database (Denmark)
Krarup, Christian; Moldovan, Mihai
2009-01-01
counterparts in the peripheral nervous system, in some instances without peripheral nervous system symptoms. Both hereditary and acquired demyelinating neuropathies have been studied and the effects on nerve pathophysiology have been compared with degeneration and regeneration of axons. SUMMARY: Excitability......PURPOSE OF REVIEW: The review is aimed at providing information about the role of nerve excitability studies in peripheral nerve disorders. It has been known for many years that the insight into peripheral nerve pathophysiology provided by conventional nerve conduction studies is limited. Nerve...... excitability studies are relatively novel but are acquiring an increasingly important role in the study of peripheral nerves. RECENT FINDINGS: By measuring responses in nerve that are related to nodal function (strength-duration time constant, rheobase and recovery cycle) and internodal function (threshold...
12. Sampling system for pulsed signals. Study of the radioactive lifetimes of excited 32P1/2 and 32P3/2 states of Na, excited by a tunable dye laser
International Nuclear Information System (INIS)
Thomas, P.; Campos, J.
1979-01-01
A system for sampling and averaging repetitive signals in the order of nanoseconds is discussed. The system uses as storage memory a multichannel analyzer operating in multi scaling mode. This instrument is employed for the measurement of atomic level lifetimes using a dye laser to excite the atoms and is applied to the study of lifetimes of the 3 2 P1/2 and 3 2 P3/2 states of sodium. (Author) 32 refs
13. Sweep excitation with order tracking: A new tactic for beam crack analysis
Science.gov (United States)
Wei, Dongdong; Wang, KeSheng; Zhang, Mian; Zuo, Ming J.
2018-04-01
Crack detection in beams and beam-like structures is an important issue in industry and has attracted numerous investigations. A local crack leads to global system dynamics changes and produce non-linear vibration responses. Many researchers have studied these non-linearities for beam crack diagnosis. However, most reported methods are based on impact excitation and constant frequency excitation. Few studies have focused on crack detection through external sweep excitation which unleashes abundant dynamic characteristics of the system. Together with a signal resampling technique inspired by Computed Order Tracking, this paper utilize vibration responses under sweep excitations to diagnose crack status of beams. A data driven method for crack depth evaluation is proposed and window based harmonics extracting approaches are studied. The effectiveness of sweep excitation and the proposed method is experimentally validated.
14. New features of nuclear excitation by {alpha} particles scattering; Nouveaux aspects de l'excitation nucleaire par diffusion de particules {alpha}
Energy Technology Data Exchange (ETDEWEB)
Saudinos, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-07-01
Inelastic scattering of medium energy a particles by nuclei is known to excite preferentially levels of collective character. We have studied the scattering of isotopically enriched targets of Ca, Fe, Ni, Cu, Zn. In part I, we discuss the theoretical features of the interaction. In part II, we describe the experimental procedure. Results are presented and analysed in part III. {alpha} particles scattering by Ca{sup 40} is showed to excite preferentially odd parity levels. In odd nuclei we have observed multiplets due to the coupling of the odd nucleon with the even-even core vibrations. For even-even nuclei, a few levels are excited with lower cross-sections between the well-known first 2{sup +} and 3{sup -} states. Some could be members of the two phonon quadrupole excitation and involve a double nuclear excitation process. (author) [French] On sait que la diffusion inelastique des particules alpha de moyenne energie excite preferentiellement des niveaux de caractere collectif. Nous avons etudie la diffusion des particules alpha de 44 MeV du cyclotron de Saclay par des isotopes separes de Ca, Fe, Ni, Cu, Zn. Dans la premiere partie nous exposons les theories de cette interaction. Dans la seconde nous decrivons le systeme experimental. Les resultats sont donnes dans la troisieme partie. Nous montrons que les niveaux excites preferentiellement pour {sup 40}Ca par diffusion ({alpha},{alpha}') sont de parite negative. Dans les noyaux pair-impair nous avons observe des multiplets dus au couplage du nucleon celibataire avec les vibrations du coeur pair-pair. Pour les noyaux pair-pair nous avons pu etudier entre le premier niveau 2{sup +} et le niveau 3{sup -} deja bien connus certains etats plus faiblement excites. Il semble qu'ils sont dus a une excitation quadrupolaire a deux phonons et impliquent un processus de double excitation nucleaire. (auteur)
15. Suppression of radiation excitation in focusing environment
International Nuclear Information System (INIS)
Huang, Z.; Ruth, R.D.
1996-12-01
Radiation damping and quantum excitation in an electron damping ring and a straight focusing channel are reviewed. They are found to be the two limiting cases in the study of a general bending and focusing combined system. In the intermediate regime where the radiation formation length is comparable to the betatron wavelength, quantum excitation can be exponentially suppressed by focusing field. This new regime may have interesting applications in the generation of ultra-low emittance beams
16. Method of producing excited states of atomic nuclei
International Nuclear Information System (INIS)
Morita, M.; Morita, R.
1976-01-01
A method is claimed of producing excited states of atomic nuclei which comprises bombarding atoms with x rays or electrons, characterized in that (1) in the atoms selected to be produced in the excited state of their nuclei, (a) the difference between the nuclear excitation energy and the difference between the binding energies of adequately selected two electron orbits is small enough to introduce the nuclear excitation by electron transition, and (b) the system of the nucleus and the electrons in the case of ionizing an orbital electron in said atoms should satisfy the spin and parity conservation laws; and (2) the energy of the bombarding x rays or electrons should be larger than the binding energy of one of the said two electron orbits which is located at shorter distance from the atomic nucleus. According to the present invention, atomic nuclei can be excited in a relatively simple manner without requiring the use of large scale apparatus, equipment and production facilities, e.g., factories. It is also possible to produce radioactive substances or separate a particular isotope with an extremely high purity from a mixture of isotopes by utilizing nuclear excitation
17. Study of the excitation mechanisms of the second positive system in the negative glow of a N2-Ar discharge
International Nuclear Information System (INIS)
Isola, L; Lopez, M; Gomez, B J
2011-01-01
In an Ar-N 2 discharge, the high excitation transfer from Ar( 3 P 2,0 ) to N 2 produces an overpopulation of the high rotational levels of the bands of the second positive system (SPS), and so the spectra interpretation is not straightforward. This paper presents a fit function for the SPS bands measured in Ar-N 2 , which allows us to study the excitation process contributions to the N 2 (C) level. The procedure was tested in the negative glow of a pulsed Ar-N 2 discharge at a pressure of 2.5 Torr, for different mixture concentrations. In this discharge, through the fitting, it was possible to calculate the variation of the N 2 (C) densities produced by different excitation processes as well as the variation of Ar metastable density.
18. Anisotropy of electronic states excited in ion-atom collisions
International Nuclear Information System (INIS)
Boskamp, E.B.
1983-01-01
The author reports coincidence measurements made on the He + + Ne and He + + He systems. The complex population amplitudes for the magnetic sublevels of the investigated excited states, Ne(2p 4 3s 2 ) 1 D and He(2p 2 ) 1 D, were completely determined and possible excitation mechanisms are described. (Auth.)
19. On isospin excitation energy
International Nuclear Information System (INIS)
Li Wenfei; Zhang Fengshou; Chen Liewen
2001-01-01
Within the framework of Hartree-Fock theory using the extended Skyrme effective interaction, the isospin excitation energy as a function of relative neutron excess δ was investigated at different temperatures and densities. It was found that the isospin excitation energy decreased with the increment of temperature and/or the decrement of density. The authors pointed out that the decrement of isospin excitation energy was resulted from the weakening of quantum effect with increment of temperature and/or decrement of density. Meanwhile, the relationship between the isospin excitation energy and the symmetry energy was discussed and found that the symmetry energy was just a part of the isospin excitation energy. With increasing temperature and decreasing density, the contribution of the symmetry energy to the isospin excitation energy becomes more and more important. The isospin excitation energy as a function of relative neutron excess was also investigated using different potential parameters. The results shows that the isospin excitation energy is almost independent of the incompressibility and the effective mass, but strongly depends on the symmetry energy strength coefficient, which indicates that it is possible to extract the symmetry energy of the nuclear equation of state by investigating the isospin excitation energy in experiments
20. Analysis and control of the effects of over excitation limiters on the stability of the Itaipu HVAC transmission system
Energy Technology Data Exchange (ETDEWEB)
Jardim, J L; Macedo, N J; Santo, S E; Praca, A S [FURNAS Centrais Eletricas S.A., Rio de Janeiro, RJ (Brazil)
1994-12-31
The effect of over excitation limiters on power system voltage stability is presented in this paper. A linear analysis based on system eigenvalues for various operating conditions shows that voltage collapse is essentially a dynamic phenomenon. Time simulations using digital tools and real-time simulator were performed to verify lin ear results and study large disturbances. A control system designed to keep system in secure region is proposed. (author) 3 refs., 9 figs.
1. Statistical properties of highly excited quantum eigenstates of a strongly chaotic system
International Nuclear Information System (INIS)
Aurich, R.; Steiner, F.
1992-06-01
Statistical properties of highly excited quantal eigenstates are studied for the free motion (geodesic flow) on a compact surface of constant negative curvature (hyperbolic octagon) which represents a strongly chaotic system (K-system). The eigenstates are expanded in a circular-wave basis, and it turns out that the expansion coefficients behave as Gaussian pseudo-random numbers. It is shown that this property leads to a Gaussian amplitude distribution P(ψ) in the semiclassical limit, i.e. the wavefunctions behave as Gaussian random functions. This behaviour, which should hold for chaotic systems in general, is nicely confirmed for eigenstates lying 10000 states above the ground state thus probing the semiclassical limit. In addition, the autocorrelation function and the path-correlation function are calculated and compared with a crude semiclassical Bessel-function approximation. Agreement with the semiclassical prediction is only found, if a local averaging is performed over roughly 1000 de Broglie wavelengths. On smaller scales, the eigenstates show much more structure than predicted by the first semiclassical approximation. (orig.)
2. Multiflavour excited mesons from the fifth dimension
Energy Technology Data Exchange (ETDEWEB)
Paredes, Angel [Centre de Physique Theorique, Ecole Polytechnique, 91128 Palaiseau (France)]. E-mail: [email protected]; Talavera, Pere [Departament de Fisica i Enginyeria Nuclear, Universitat Politecnica de Catalunya, Jordi Girona 1-3, E-08034 Barcelona (Spain)]. E-mail: [email protected]
2005-05-02
We study the Regge trajectories and the quark-antiquark energy in excited hadrons composed by different dynamical mass constituents via the gauge/string correspondence. First we exemplify the procedure in a supersymmetric system, D3-D7, in the extremal case. Afterwards we discuss the model dual to large-N{sub c} QCD, D4-D6 system. In the latter case we find the field theory expected gross features of vector like theories: the spectrum resembles that of heavy quarkonia and the Chew-Frautschi plot of the singlet and first excited states is in qualitative agreement with those of lattice QCD. We stress the salient points of including different constituents masses.
3. Anisotropy in the simultaneous excitation of two colliding atoms to various substate combinations
International Nuclear Information System (INIS)
Moorman, L.
1987-01-01
In this thesis double-atom excitation (DAE) processes in atomic collision experiments are studied by measuring the angular correlation of two coincident photons emitted by both excited collision particles. The analytical expression for the angular correlation function is derived which contains as adjustable parameters the various (complex) excitation amplitudes integrated over all scattering angles. The He+He system is investigated, for projectile energies between 0.5 and 3.5 keV, in which both particles are excited simultaneously to the 2 1 P state. The relation between photon correlations and atomic state correlations is investigated and the density matrix elements are calculated for a statistical distribution of the excited atomic substates into which a certain symmetry is incorporated. Collisions between metastable and groundstate He atoms are considered. Single-photon spectra are presented and compared with spectra from the He+He collision system. Coincidence measurements were performed on these collision systems to study possible double-atom excitations. Coincidences between two ultraviolet as well as an ultraviolet and a visible photon were measu0515 Also a measurement is reported of the relative population of the magnetic substates of the 3 1 D state of helium. Coincidence measurements on two ultraviolet photons emitted upon Ne-Ne and He-Ne collisions are described and the double-atom excitations for these systems are studied. For Ne+Ne no coincidence peaks were found. For He+Ne double-atom excitation was observed and from the measured angular correlations the corresponding density matrix elements for some kinetic energies of the projectile. (Auth.)
4. Asymmetric excitation of surface plasmons by dark mode coupling
KAUST Repository
Zhang, X.
2016-02-19
Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.
5. Asymmetric excitation of surface plasmons by dark mode coupling
KAUST Repository
Zhang, X.; Xu, Q.; Li, Q.; Xu, Y.; Gu, J.; Tian, Z.; Ouyang, C.; Liu, Y.; Zhang, S.; Zhang, Xixiang; Han, J.; Zhang, W.
2016-01-01
Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.
6. Study of a Quantum Dot in an Excited State
Science.gov (United States)
Slamet, Marlina; Sahni, Viraht
We have studied the first excited singlet state of a quantum dot via quantal density functional theory (QDFT). The quantum dot is represented by a 2D Hooke's atom in an external magnetostatic field. The QDFT mapping is from an excited singlet state of this interacting system to one of noninteracting fermions in a singlet ground state. The results of the study will be compared to (a) the corresponding mapping from a ground state of the quantum dot and (b) to the similar mapping from an excited singlet state of the 3D Hooke's atom.
7. Non-orthogonal configuration interaction for the calculation of multielectron excited states
Energy Technology Data Exchange (ETDEWEB)
Sundstrom, Eric J., E-mail: [email protected]; Head-Gordon, Martin [Department of Chemistry, University of California Berkeley, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2014-03-21
We apply Non-orthogonal Configuration Interaction (NOCI) to molecular systems where multielectron excitations, in this case double excitations, play a substantial role: the linear polyenes and β-carotene. We demonstrate that NOCI when applied to systems with extended conjugation, provides a qualitatively correct wavefunction at a fraction of the cost of many other multireference treatments. We also present a new extension to this method allowing for purification of higher-order spin states by utilizing Generalized Hartree-Fock Slater determinants and the details for computing 〈S{sup 2}〉 for the ground and excited states.
8. Effects of Energy Dissipation on the Parametric Excitation of a Coupled Qubit-Cavity System
Science.gov (United States)
Remizov, S. V.; Zhukov, A. A.; Shapiro, D. S.; Pogosov, W. V.; Lozovik, Yu. E.
2018-02-01
We consider a parametrically driven system of a qubit coupled to a cavity taking into account different channels of energy dissipation. We focus on the periodic modulation of a single parameter of this hybrid system, which is the coupling constant between the two subsystems. Such a modulation is possible within the superconducting realization of qubit-cavity coupled systems, characterized by an outstanding degree of tunability and flexibility. Our major result is that energy dissipation in the cavity can enhance population of the excited state of the qubit in the steady state, while energy dissipation in the qubit subsystem can enhance the number of photons generated from vacuum. We find optimal parameters for the realization of such dissipation-induced amplification of quantum effects. Our results might be of importance for the full control of quantum states of coupled systems as well as for the storage and engineering of quantum states.
9. Consideration of Gyroscopic Effect in Fault Detection and Isolation for Unbalance Excited Rotor Systems
Directory of Open Access Journals (Sweden)
Zhentao Wang
2012-01-01
Full Text Available Fault detection and isolation (FDI in rotor systems often faces the problem that the system dynamics is dependent on the rotor rotary frequency because of the gyroscopic effect. In unbalance excited rotor systems, the continuously distributed unbalances are hard to be determined or estimated accurately. The unbalance forces as disturbances make fault detection more complicated. The aim of this paper is to develop linear time invariant (LTI FDI methods (i.e., with constant parameters for rotor systems under consideration of gyroscopic effect and disturbances. Two approaches to describe the gyroscopic effect, that is, as unknown inputs and as model uncertainties, are investigated. Based on these two approaches, FDI methods are developed and the results are compared regarding the resulting FDI performances. Results are obtained by the application in a rotor test rig. Restrictions for the application of these methods are discussed.
10. Elementary excitations in nuclei
International Nuclear Information System (INIS)
Lemmer, R.H.
1987-01-01
The role of elementary quasi-particle and quasi-hole excitations is reviewed in connection with the analysis of data involving high-lying nuclear states. This article includes discussions on: (i) single quasi-hole excitations in pick-up reactions, (ii) the formation of single quasi-hole and quasi-particle excitations (in different nuclei) during transfer reactions, followed by (iii) quasi-particle quasi-hole excitations in the same nucleus that are produced by photon absorption. Finally, the question of photon absorption in the vicinity of the elementary Δ resonance is discussed, where nucleonic as well as nuclear degrees of freedom can be excited
11. Soil-structure interaction effects for laterally excited liquid-tank system
International Nuclear Information System (INIS)
Tang, Yu; Veletsos, A.S.
1992-01-01
Following a brief review of the mechanical model for liquid-storage tanks which permits consideration of the effects of tank and ground flexibility, and lateral and rocking base excitations, the effects of both kinematic and inertia interaction effects on the response of the tank-liquid system are examined and elucidated. The free-field motion is defined by a power spectral density function and an incoherence function, which characterizes the spatial variability of the ground motion due to the vertically incident incoherence waves. The quantities examined are the ensemble means of the peak values of the response. The results are compared with those obtained for no soil-structure interaction and for kinematic interaction to elucidate the nature and relative importance of the two interactions. Only the impulsive actions are examined, the convective actions are for all practical purposes unaffected by both kinematic and inertia interactions. It is shown that the major reduction of the response is attributed to inertia interaction. 20 refs
12. Electronic excitations in metallic systems: from defect annihilation to track formation
International Nuclear Information System (INIS)
Dunlop, A.; Lesueur, D.
1991-01-01
This paper presents an overview of the effects of high electronic energy deposition in metallic targets irradiated with GeV heavy ions. The main result of these investigations is that high electronic excitations lead to various and sometimes conflicting effects according to the nature of the target: - partial annealing of the defects induced by elastic collisions, - creation of additional disorder, - phase transformation (tracks formation and amorphization), - anisotropic growth. These different effects of high electronic energy deposition in metallic targets are probably manifestations at various degrees of the same basic energy transfer process between the excited electrons and the target atoms. Up to now no theoretical model explains these effects. 24 refs
13. Pure odd-order oscillators with constant excitation
Science.gov (United States)
Cveticanin, L.
2011-02-01
In this paper the excited vibrations of a truly nonlinear oscillator are analyzed. The excitation is assumed to be constant and the nonlinearity is pure (without a linear term). The mathematical model is a second-order nonhomogeneous differential equation with strong nonlinear term. Using the first integral, the exact value of period of vibration i.e., angular frequency of oscillator described with a pure nonlinear differential equation with constant excitation is analytically obtained. The closed form solution has the form of gamma function. The period of vibration depends on the value of excitation and of the order and coefficient of the nonlinear term. For the case of pure odd-order-oscillators the approximate solution of differential equation is obtained in the form of trigonometric function. The solution is based on the exact value of period of vibration. For the case when additional small perturbation of the pure oscillator acts, the so called 'Cveticanin's averaging method' for a truly nonlinear oscillator is applied. Two special cases are considered: one, when the additional term is a function of distance, and the second, when damping acts. To prove the correctness of the method the obtained results are compared with those for the linear oscillator. Example of pure cubic oscillator with constant excitation and linear damping is widely discussed. Comparing the analytically obtained results with exact numerical ones it is concluded that they are in a good agreement. The investigations reported in the paper are of special interest for those who are dealing with the problem of vibration reduction in the oscillator with constant excitation and pure nonlinear restoring force the examples of which can be found in various scientific and engineering systems. For example, such mechanical systems are seats in vehicles, supports for machines, cutting machines with periodical motion of the cutting tools, presses, etc. The examples can be find in electronics
14. Excitation equilibria in plasmas: a classification
International Nuclear Information System (INIS)
Mullen, J.-J.A.M. van der.
1986-01-01
In this thesis the author presents a classification of plasmas based on the atomic state distribution function. The study is based on the relation between the distribution function and the underlying processes and starts with the proper understanding of thermodynamic equilibrium (TE). Four types of proper balances are relevant: The 'Maxwell balance' of kinetic energy transfer, the 'Boltzmann balance' of excitation/deexcitation, the 'Saha balance' of ionization/recombination and the 'Planck balance' for interaction of atoms with radiation. Special attention is paid to the distribution function of the ionizing excitation saturation balance. The classification theory of the distribution functions in relation with underlying balances is supported by experimental evidence in an ionizing argon plasma. The AR I system provides a pertinent support of the theory. Experimental facts found in the AR II system can be interpreted in global terms. (Auth.)
15. Development and performance test of picosecond pulse x-ray excited streak camera system for scintillator characterization
International Nuclear Information System (INIS)
Yanagida, Takayuki; Fujimoto, Yutaka; Yoshikawa, Akira
2010-01-01
To observe time and wavelength-resolved scintillation events, picosecond pulse X-ray excited streak camera system is developed. The wavelength range spreads from vacuum ultraviolet (VUV) to near infrared region (110-900 nm) and the instrumental response function is around 80 ps. This work describes the principle of the newly developed instrument and the first performance test using BaF 2 single crystal scintillator. Core valence luminescence of BaF 2 peaking around 190 and 220 nm is clearly detected by our system, and the decay time turned out to be of 0.7 ns. These results are consistent with literature and confirm that our system properly works. (author)
16. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection
DEFF Research Database (Denmark)
Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter
2017-01-01
In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum......, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based...... on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved...
17. Clinical Comparison of Pulse and Chirp Excitation
DEFF Research Database (Denmark)
Pedersen, Morten Høgholm; Misaridis, T.; Jensen, Jørgen Arendt
2002-01-01
Coded excitation (CE) using frequency modulated signals (chirps) combined with modified matched filtering has earlier been presented showing promising results in simulations and in-vitro. In this study an experimental ultrasound system is evaluated in a clinical setting, where image sequences...... and short pulse excitation to simultaneously produce identical image sequences using both techniques. Nine healthy male volunteers were scanned in abdominal locations. All sequences were evaluated by 3 skilled medical doctors, blinded to each other and to the technique used. They assessed the depth (1...
18. Pilot testing of a hydraulic bridge exciter
Directory of Open Access Journals (Sweden)
2015-01-01
Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.
19. High Tc Superconducting Magnet Excited by a Semiconductor Thermoelectric Element
Science.gov (United States)
Kuriyama, T.; Ono, M.; Tabe, S.; Oguchi, A.; Okamura, T.
2006-04-01
A high Tc superconducting (HTS) magnet excited by a thermal electromotive force of a thermoelectric element is studied. This HTS magnet has the advantages of compactness, lightweight and continuous excitation in comparison with conventional HTS magnets, because this HTS magnet does not need a large external power source. In this system, a heat input into the cryogenic environment is necessary to excite the thermoelectric element for constant operation. This heat generation, however, causes a rise in temperature of an HTS coil and reduces the system performance. In this paper, a newly designed magnet system which adopted a two-stage GM cryocooler was investigated. It enabled us to control the temperature of a thermoelectric element and that of an HTS coil independently. The temperature of the HTS coil could be kept at 10-20 K at the second stage of the GM cryocooler, while the thermoelectric element could be excited at higher temperature in the range of 50-70 K at the first stage, where the performance of the thermoelectric element was higher. The experimental results on this HTS magnet are shown and the possibility of the thermoelectric element as a main power source of the HTS magnets is discussed.
20. Energy harvesting from coherent resonance of horizontal vibration of beam excited by vertical base motion
Energy Technology Data Exchange (ETDEWEB)
Lan, C. B.; Qin, W. Y. [Department of Engineering Mechanics, Northwestern Polytechnical University, Xi' an 710072 (China)
2014-09-15
This letter investigates the energy harvesting from the horizontal coherent resonance of a vertical cantilever beam subjected to the vertical base excitation. The potential energy of the system has two symmetric potential wells. So, under vertical excitation, the system can jump between two potential wells, which will lead to the large vibration in horizontal direction. Two piezoelectric patches are pasted to harvest the energy. From experiment, it is found that the vertical excitation can make the beam turn to be bistable. The system can transform vertical vibration into horizontal vibration of low frequency when excited by harmonic motion. The horizontal coherence resonance can be observed when excited by a vertical white noise. The corresponding output voltages of piezoelectric films reach high values.
1. Comparison of exciplex generation under optical and X-ray excitation
Science.gov (United States)
Kipriyanov, A. A.; Melnikov, A. R.; Stass, D. V.; Doktorov, A. B.
2017-09-01
Exciplex generation under optical and X-ray excitation in identical conditions is experimentally compared using a specially chosen model donor-acceptor system, anthracene (electron acceptor) and N,N-dimethylaniline (electron donor) in non-polar solution, and the results are analyzed and interpreted based on analytically calculated luminescence quantum yields. Calculations are performed on the basis of kinetic equations for multistage schemes of bulk exciplex production reaction under optical excitation and combination of bulk and geminate reactions of radical ion pairs under X-ray excitation. These results explain the earlier experimentally found difference in the ratio of the quantum yields of exciplexes and excited electron acceptors (exciplex generation efficiency) and the corresponding change in the exciplex generation efficiency under X-irradiation as compared to the reaction under optical excitation.
2. The CLAS Excited Baryon Program at Jefferson Laboratory
International Nuclear Information System (INIS)
Crede, Volker
2009-01-01
Nucleons are complex systems of confined quarks and exhibit characteristic spectra of excited states. Highly excited nucleon states are sensitive to details of quark confinement which is poorly understood within Quantum Chromodynamics (QCD), the fundamental theory of strong interactions. Thus, measurements of excited states and the corresponding determination of their properties are needed to come to a better understanding of how confinement works in nucleons. However, the excited states of the nucleon cannot simply be inferred from cleanly separated spectral lines. Quite the contrary, a spectral analysis in nucleon resonance physics is challenging because of the fact that the resonances are broadly overlapping states which decay into a multitude of final states involving mesons and baryons. To provide a consistent and complete picture of an individual nucleon resonance, the various possible production and decay channels must be treated in a multi-channel framework that permits separat
3. Sub-50 fs excited state dynamics of 6-chloroguanine upon deep ultraviolet excitation.
Science.gov (United States)
Mondal, Sayan; Puranik, Mrinalini
2016-05-18
The photophysical properties of natural nucleobases and their respective nucleotides are ascribed to the sub-picosecond lifetime of their first singlet states in the UV-B region (260-350 nm). Electronic transitions of the ππ* type, which are stronger than those in the UV-B region, lie at the red edge of the UV-C range (100-260 nm) in all isolated nucleobases. The lowest energetic excited states in the UV-B region of nucleobases have been investigated using a plethora of experimental and theoretical methods in gas and solution phases. The sub-picosecond lifetime of these molecules is not a general attribute of all nucleobases but specific to the five primary nucleobases and a few xanthine and methylated derivatives. To determine the overall UV photostability, we aim to understand the effect of more energetic photons lying in the UV-C region on nucleobases. To determine the UV-C initiated photophysics of a nucleobase system, we chose a halogen substituted purine, 6-chloroguanine (6-ClG), that we had investigated previously using resonance Raman spectroscopy. We have performed quantitative measurements of the resonance Raman cross-section across the Bb absorption band (210-230 nm) and constructed the Raman excitation profiles. We modeled the excitation profiles using Lee and Heller's time-dependent theory of resonance Raman intensities to extract the initial excited state dynamics of 6-ClG within 30-50 fs after photoexcitation. We found that imidazole and pyrimidine rings of 6-ClG undergo expansion and contraction, respectively, following photoexcitation to the Bb state. The amount of distortions of the excited state structure from that of the ground state structure is reflected by the total internal reorganization energy that is determined at 112 cm(-1). The contribution of the inertial component of the solvent response towards the total reorganization energy was obtained at 1220 cm(-1). In addition, our simulation also yields an instantaneous response of the first
4. A density matrix renormalization group study of low-lying excitations ...
Symmetrized density-matrix-renormalization-group calculations have been carried out, within Pariser-Parr-Pople Hamiltonian, to explore the nature of the ground and low-lying excited states of long polythiophene oligomers. We have exploited 2 symmetry and spin parity of the system to obtain excited states of ...
5. Integrated modeling and analysis of ball screw feed system and milling process with consideration of multi-excitation effect
Science.gov (United States)
Zhang, Xing; Zhang, Jun; Zhang, Wei; Liang, Tao; Liu, Hui; Zhao, Wanhua
2018-01-01
The present researches about feed drive system and milling process are almost independent with each other, and ignore the interaction between the two parts, especially the influence of nonideal motion of feed drive system on milling process. An integrated modeling method of ball screw feed system and milling process with multi-excitation effect is proposed in this paper. In the integrated model, firstly an analytical model of motor harmonic torque with consideration of asymmetrical drive circuit and asymmetrical permanent magnet is given. Then, the numerical simulation procedure of cutter/workpiece engagement during milling process with displacement fluctuation induced by harmonic torque is put forward, which is followed by the solving flow for the proposed integrated model. Based on the integrated model, a new kind of quality defect shown as contour low frequency oscillation on machined surface is studied by experiments and simulations. The results demonstrate that the forming mechanism of the contour oscillation can be ascribed to the multi-excitation effect with motor harmonic torque and milling force. Moreover, the influence of different milling conditions on the contour oscillation characteristics, particularly on surface roughness, are further discussed. The results indicate that it is necessary to explain the cause of the new kind of quality defect with a view of system integration.
6. Adaptive transition rates in excitable membranes
Directory of Open Access Journals (Sweden)
Shimon Marom
2009-02-01
Full Text Available Adaptation of activity in excitable membranes occurs over a wide range of timescales. Standard computational approaches handle this wide temporal range in terms of multiple states and related reaction rates emanating from the complexity of ionic channels. The study described here takes a different (perhaps complementary approach, by interpreting ion channel kinetics in terms of population dynamics. I show that adaptation in excitable membranes is reducible to a simple Logistic-like equation in which the essential non-linearity is replaced by a feedback loop between the history of activation and an adaptive transition rate that is sensitive to a single dimension of the space of inactive states. This physiologically measurable dimension contributes to the stability of the system and serves as a powerful modulator of input-output relations that depends on the patterns of prior activity; an intrinsic scale free mechanism for cellular adaptation that emerges from the microscopic biophysical properties of ion channels of excitable membranes.
7. Dynamics of the edge excitations in the FQH effects
International Nuclear Information System (INIS)
Wen, X.G.
1994-01-01
Fractional quantum Hall effects (FQHE) discovered by Tsui, Stormer and Gossard open a new era in theory of strongly correlated system. In the first time the authors have to completely abandon the theories based on the single-body picture and use an intrinsic many-body theory proposed by Laughlin and others to describe the FQHE. Due to the repulsive interaction, the strongly correlated FQH liquid is an incompressible state despite the first Landau level is only partially filled. All the bulk excitations in the FQH states have finite energy gaps. The FQH states and insulators are similar in the sense that both states have finite energy gap and short ranged electron propagators. Because of this similarity, it is puzzling that the FQH systems apparently have very different transport properties than ordinary insulators. Halperin first point out that the integral quantum Hall (IQH) states contain gapless edge excitations. Although the electronic states in the bulk are localized, the electronic states at the edge of the sample are extended. Therefore the nontrivial transport properties of the IQH states come from the gapless edge excitations. Such an edge transport picture has been supported by many experiments. One also found that the edge excitations in the IQH states are described by a chiral 1D Fermi liquid theory. Here, the authors review the dynamical theory of the edge excitations in the FQH effects
8. Electron spectroscopy of collisional excited atoms
International Nuclear Information System (INIS)
Straten, P. van der.
1987-01-01
In this thesis measurements are described in which coincidences are detected between scattered projectiles and emitted electrons. This yields information on two-electron excitation processes. In order to show what can be learnt from coincidence experiments a detailed theoretical analysis is given. The transition amplitudes, which contain all the information, are introduced (ch.2). In ch.3 the experimental set-up is shown. The results for the Li + -He system are shown in ch. 7 and are compared with predictions based on the Molecular-Orbitalmodel which however does not account for two-excitation mechanisms. With the transition amplitudes also the wave function of the excited atom has been completely determined. In ch.8 the shape of the electron cloud, induced by the collision, is derived from the amplitudes. The relation between the oscillatory motion of this cloud after the collision and the correlation between the two electrons of the excited atom is discussed. In ch. 6 it is shown that the broad structures in the non-coincident energy spectra of the Li + -He system are erroneously interpretated as a result of electron emission from the (Li-He) + -quasimolecule. A model is presented which explains, based on the results obtained from the coincidence measurements, these broad structures. In ch. 4 the Post-Collision Interaction process is treated. It is shown that for high-energy collisions, in contrast with general assumptions, PCI is important. In ch. 5 the importance of PCI-processes in photoionization of atoms, followed by Auger decay, are studied. From the formulas derived in ch. 4 simple analytical results are obtained. These are applied to recent experiments and good agreement is achieved. 140 refs.; 55 figs.; 9 tabs
9. Experimental study on the kinetically induced electronic excitation in atomic collisional cascades
International Nuclear Information System (INIS)
Meyer, S.
2006-01-01
the present thesis deals with the ion-collision-induced electronic excitation of metallic solids. For this for the first time metal-insulator-metal layer systems are used for the detection of this electronic excitation. The here applied aluminium/aluminium oxide/silver layer sytems have barrier heights of 2.4 eV on the aluminium respectively 3.3 eV on the silver side. With the results it could uniquely be shown that the electronic excitation is generated by kinetic processes, this excitation dependenc on the kinetic energy of the colliding particles, and the excitation dependes on the charge state of the projectile
10. A scalable piezoelectric impulse-excited energy harvester for human body excitation
International Nuclear Information System (INIS)
Pillatsch, P; Yeatman, E M; Holmes, A S
2012-01-01
Harvesting energy from low-frequency and non-harmonic excitations typical of human motion presents specific challenges. While resonant devices do have an advantage in environments where the excitation frequency is constant, and while they can make use of the entire proof mass travel range in the case of excitation amplitudes that are smaller than the internal displacement limit, they are not suitable for body applications since the frequencies are random and the amplitudes tend to be larger than the device size. In this paper a piezoelectric, impulse-excited approach is presented. A cylindrical proof mass actuates an array of piezoelectric bi-morph beams through magnetic attraction. After the initial excitation these transducers are left to vibrate at their natural frequency. This increases the operational frequency range as well as the electromechanical coupling. The principle of impulse excitation is discussed and a centimetre-scale functional model is introduced as a proof of concept. The obtained data show the influence of varying the frequency, acceleration and proof mass. Finally, a commercially available integrated circuit for voltage regulation is tested. At a frequency of 2 Hz and an acceleration of 2.7 m s −2 a maximal power output of 2.1 mW was achieved. (paper)
11. Magnetic field effects on exciplex-forming systems: the effect on the locally excited fluorophore and its dependence on free energy.
Science.gov (United States)
Kattnig, Daniel R; Rosspeintner, Arnulf; Grampp, Günter
2011-02-28
This study addresses magnetic field effects in exciplex forming donor-acceptor systems. For moderately exergonic systems, the exciplex and the locally excited fluorophore emission are found to be magneto-sensitive. A previously introduced model attributing this finding to excited state reversibility is confirmed. Systems characterised by a free energy of charge separation up to approximately -0.35 eV are found to exhibit a magnetic field effect on the fluorophore. A simple three-state model of the exciplex is introduced, which uses the reaction distance and the asymmetric electron transfer reaction coordinate as pertinent variables. Comparing the experimental emission band shapes with those predicted by the model, a semi-quantitative picture of the formation of the magnetic field effect is developed based on energy hypersurfaces. The model can also be applied to estimate the indirect contribution of the exchange interaction, even if the perturbative approach fails. The energetic parameters that are essential for the formation of large magnetic field effects on the exciplex are discussed.
12. Electron impact excitation and ionization of laser-excited sodium atoms Na*(7d)
International Nuclear Information System (INIS)
Nienhaus, J.; Dorn, A.; Mehlhorn, W.; Zatsarinny, O.I.
1997-01-01
We have investigated the ejected-electron spectrum following impact excitation and ionization of laser-excited Na * (nl) atoms by 1.5 keV electrons. By means of two-laser excitation 3s → 3p 3/2 → 7d and subsequent cascading transitions about 8% (4%) of the target atoms were in excited states with n > 3 (7d). The experimental ejected-electron spectrum due to the decay of Auger and autoionization states of laser-excited atoms Na * (nl) with n = 4-7 has been fully interpreted by comprehensive calculations of the energies, cross sections and decay probabilities of the corresponding states. The various processes contributing to the ejected-electron spectrum are with decreasing magnitude: 2s ionization leading to 2s2p 6 nl Auger states, 2p → 3s excitation leading to 2p 5 3s( 1 P)nl autoionization states and 2s → 3l' excitation leading to 2s2p 6 3l'( 1 L)nl autoionization states. (Author)
13. High-Resolution Spectroscopy of Jet-Cooled 1,1 '-Diphenylethylene: Electronically Excited and Ionic States of a Prototypical Cross-Conjugated System
NARCIS (Netherlands)
Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C. A.; Zgierski, M. Z.; Buma, W. J.
2011-01-01
The photophysics of a prototypical cross-conjugated pi-system, 1,1'-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio
14. Perturbation expansion theory corrected from basis set superposition error. I. Locally projected excited orbitals and single excitations.
Science.gov (United States)
Nagata, Takeshi; Iwata, Suehiro
2004-02-22
The locally projected self-consistent field molecular orbital method for molecular interaction (LP SCF MI) is reformulated for multifragment systems. For the perturbation expansion, two types of the local excited orbitals are defined; one is fully local in the basis set on a fragment, and the other has to be partially delocalized to the basis sets on the other fragments. The perturbation expansion calculations only within single excitations (LP SE MP2) are tested for water dimer, hydrogen fluoride dimer, and colinear symmetric ArM+ Ar (M = Na and K). The calculated binding energies of LP SE MP2 are all close to the corresponding counterpoise corrected SCF binding energy. By adding the single excitations, the deficiency in LP SCF MI is thus removed. The results suggest that the exclusion of the charge-transfer effects in LP SCF MI might indeed be the cause of the underestimation for the binding energy. (c) 2004 American Institute of Physics.
15. The blue light indicator in rubidium 5S-5P-5D cascade excitation
Science.gov (United States)
Raja, Waseem; Ali, Md. Sabir; Chakrabarti, Alok; Ray, Ayan
2017-07-01
The cascade system has played an important role in contemporary research areas related to fields like Rydberg excitation, four wave mixing and non-classical light generation, etc. Depending on the specific objective, co or counter propagating pump-probe laser experimental geometry is followed. However, the stepwise excitation of atoms to states higher than the first excited state deals with increasingly much fewer number of atoms even compared to the population at first excited level. Hence, one needs a practical indicator to study the complex photon-atom interaction of the cascade system. Here, we experimentally analyze the case of rubidium 5S → 5P → 5D as a specimen of two-step excitation and highlight the efficacy of monitoring one branch, which emits 420 nm, of associated cascade decay route 5D → 6P → 5S, as an effective monitor of the coherence in the system.
16. Multipole giant resonances in highly excited nuclei
International Nuclear Information System (INIS)
Xia Keding; Cai Yanhuang
1989-01-01
The isoscalar giant surface resonance and giant dipole resonance in highly excited nuclei are discussed. Excitation energies of the giant modes in 208 Pb are calculated in a simplified model, using the concept of energy wieghted sum rule (EWSR), and the extended Thomas-Fermi approximation at the finite temperature is employed to describe the finite temperature is employed to describe the finite temperature equilibrium state. It is shown that EWSR and the energy of the resonance depend only weakly on temperature in the system. This weak dependence is analysed
17. A Solution Method for Linear and Geometrically Nonlinear MDOF Systems with Random Properties subject to Random Excitation
DEFF Research Database (Denmark)
Micaletti, R. C.; Cakmak, A. S.; Nielsen, Søren R. K.
structural properties. The resulting state-space formulation is a system of ordinary stochastic differential equations with random coefficient and deterministic initial conditions which are subsequently transformed into ordinary stochastic differential equations with deterministic coefficients and random......A method for computing the lower-order moments of randomly-excited multi-degree-of-freedom (MDOF) systems with random structural properties is proposed. The method is grounded in the techniques of stochastic calculus, utilizing a Markov diffusion process to model the structural system with random...... initial conditions. This transformation facilitates the derivation of differential equations which govern the evolution of the unconditional statistical moments of response. Primary consideration is given to linear systems and systems with odd polynomial nonlinearities, for in these cases...
18. Non-linear vibrating systems excited by a nonideal energy source with a large slope characteristic
Science.gov (United States)
González-Carbajal, Javier; Domínguez, Jaime
2017-11-01
This paper revisits the problem of an unbalanced motor attached to a fixed frame by means of a nonlinear spring and a linear damper. The excitation provided by the motor is, in general, nonideal, which means it is affected by the vibratory response. Since the system behaviour is highly dependent on the order of magnitude of the motor characteristic slope, the case of large slope is considered herein. Some Perturbation Methods are applied to the system of equations, which allows transforming the original 4D system into a much simpler 2D system. The fixed points of this reduced system and their stability are carefully studied. We find the existence of a Hopf bifurcation which, to the authors' knowledge, has not been addressed before in the literature. These analytical results are supported by numerical simulations. We also compare our approach and results with those published by other authors.
19. Stick-Slip Analysis of a Drill String Subjected to Deterministic Excitation and Stochastic Excitation
Directory of Open Access Journals (Sweden)
Hongyuan Qiu
2016-01-01
Full Text Available Using a finite element model, this paper investigates the torsional vibration of a drill string under combined deterministic excitation and random excitation. The random excitation is caused by the random friction coefficients between the drill bit and the bottom of the hole and assumed as white noise. Simulation shows that the responses under random excitation become random too, and the probabilistic distribution of the responses at each discretized time instant is obtained. The two points, entering and leaving the stick stage, are examined with special attention. The results indicate that the two points become random under random excitation, and the distributions are not normal even when the excitation is assumed as Gaussian white noise.
20. Cerebellum tunes the excitability of the motor system: evidence from peripheral motor axons.
Science.gov (United States)
Nodera, Hiroyuki; Manto, Mario
2014-12-01
Cerebellum is highly connected with the contralateral cerebral cortex. So far, the motor deficits observed in acute focal cerebellar lesions in human have been mainly explained on the basis of a disruption of the cerebello-thalamo-cortical projections. Cerebellar circuits have also numerous anatomical and functional interactions with brainstem nuclei and projects also directly to the spinal cord. Cerebellar lesions alter the excitability of peripheral motor axons as demonstrated by peripheral motor threshold-tracking techniques in cerebellar stroke. The biophysical changes are correlated with the functional scores. Nerve excitability measurements represent an attractive tool to extract the rules underlying the tuning of excitability of the motor pathways by the cerebellum and to discover the contributions of each cerebellar nucleus in this key function, contributing to early plasticity and sensorimotor learning.
1. Improvement of low speed induction generator performances and reducing the power of excitation and voltage control system
Energy Technology Data Exchange (ETDEWEB)
Budisan, N. [Politechnica Univ. of Timisoara (Romania); Hentea, T.; Mahil, S. [Purdue Univ. Calumet, Hammond, IN (United States); Madescu, G. [Romanian Academy, Timisoara (Romania)
1996-12-31
In this paper we present the results of our investigations concerning the utilization of induction generators at very low speed. It is shown that, by proper design, it is possible to obtain high efficiency and high power factor values. The optimized induction generators require lower reactive power resulting in lower size and price of the excitation control system. 4 refs., 2 figs.
2. Isotope separation using vibrationally excited molecules
International Nuclear Information System (INIS)
Woodroffe, J.A.; Keck, J.C.
1977-01-01
A system for isotope separation or enrichment wherein molecules of a selected isotope type in a flow of molecules of plural isotope types are vibrationally excited and collided with a background gas to provide enhanced diffusivity for the molecules of the selected isotope type permitting their separate collection. The system typically is for the enrichment of uranium using a uranium hexafluoride gas in combination with a noble gas such as argon. The uranium hexafluoride molecules having a specific isotope of uranium are vibrationally excited by laser radiation. The vibrational energy is converted to a translation energy upon collision with a particle of the background gas and the added translation energy enhances the diffusivity of the selected hexafluoride molecules facilitating its condensation on collection surfaces provided for that purpose. This process is periodically interrupted and the cryogenic flow halted to permit evaporation of the collected molecules to provide a distinct, enriched flow
3. Electron-excited molecule interactions
International Nuclear Information System (INIS)
Christophorou, L.G.; Tennessee Univ., Knoxville, TN
1991-01-01
In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs
4. Linear-scaling quantum mechanical methods for excited states.
Science.gov (United States)
Yam, ChiYung; Zhang, Qing; Wang, Fan; Chen, GuanHua
2012-05-21
The poor scaling of many existing quantum mechanical methods with respect to the system size hinders their applications to large systems. In this tutorial review, we focus on latest research on linear-scaling or O(N) quantum mechanical methods for excited states. Based on the locality of quantum mechanical systems, O(N) quantum mechanical methods for excited states are comprised of two categories, the time-domain and frequency-domain methods. The former solves the dynamics of the electronic systems in real time while the latter involves direct evaluation of electronic response in the frequency-domain. The localized density matrix (LDM) method is the first and most mature linear-scaling quantum mechanical method for excited states. It has been implemented in time- and frequency-domains. The O(N) time-domain methods also include the approach that solves the time-dependent Kohn-Sham (TDKS) equation using the non-orthogonal localized molecular orbitals (NOLMOs). Besides the frequency-domain LDM method, other O(N) frequency-domain methods have been proposed and implemented at the first-principles level. Except one-dimensional or quasi-one-dimensional systems, the O(N) frequency-domain methods are often not applicable to resonant responses because of the convergence problem. For linear response, the most efficient O(N) first-principles method is found to be the LDM method with Chebyshev expansion for time integration. For off-resonant response (including nonlinear properties) at a specific frequency, the frequency-domain methods with iterative solvers are quite efficient and thus practical. For nonlinear response, both on-resonance and off-resonance, the time-domain methods can be used, however, as the time-domain first-principles methods are quite expensive, time-domain O(N) semi-empirical methods are often the practical choice. Compared to the O(N) frequency-domain methods, the O(N) time-domain methods for excited states are much more mature and numerically stable, and
5. a simple a simple excitation control excitation control excitation
African Journals Online (AJOL)
eobe
field voltages determined follow a simple quadratic relationship that offer a very simple control scheme, dependent on only the stator current. Keywords: saturated reactances, no-load field voltage, excitation control, synchronous generators. 1. Introduction. Introduction. Introduction. The commonest generator in use today is ...
6. Excitation transfer pathways in excitonic aggregates revealed by the stochastic Schrödinger equation
Energy Technology Data Exchange (ETDEWEB)
Abramavicius, Vytautas, E-mail: [email protected]; Abramavicius, Darius, E-mail: [email protected] [Faculty of Physics, Department of Theoretical Physics, Vilnius University, Saulėtekio 9, LT-10222 Vilnius (Lithuania)
2014-02-14
We derive the stochastic Schrödinger equation for the system wave vector and use it to describe the excitation energy transfer dynamics in molecular aggregates. We suggest a quantum-measurement based method of estimating the excitation transfer time. Adequacy of the proposed approach is demonstrated by performing calculations on a model system. The theory is then applied to study the excitation transfer dynamics in a photosynthetic pigment-protein Fenna-Matthews-Olson (FMO) aggregate using both the Debye spectral density and the spectral density obtained from earlier molecular dynamics simulations containing strong vibrational high-frequency modes. The obtained results show that the excitation transfer times in the FMO system are affected by the presence of the vibrational modes; however, the transfer pathways remain the same.
7. Excited states v.6
CERN Document Server
Lim, Edward C
1982-01-01
Excited States, Volume 6 is a collection of papers that discusses the excited states of molecules. The first paper discusses the linear polyene electronic structure and potential surfaces, considering both the theoretical and experimental approaches in such electronic states. This paper also reviews the theory of electronic structure and cites some experimental techniques on polyene excitations, polyene spectroscopic phenomenology, and those involving higher states of polyenes and their triplet states. Examples of these experimental studies of excited states involve the high-resolution one-pho
8. Portable vibration exciter
Science.gov (United States)
Beecher, L. C.; Williams, F. T.
1970-01-01
Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.
9. Impulses and pressure waves cause excitement and conduction in the nervous system.
Science.gov (United States)
Barz, Helmut; Schreiber, Almut; Barz, Ulrich
2013-11-01
It is general accepted, that nerval excitement and conduction is caused by voltage changes. However, the influx of fluid into an elastical tube releases impulses or pressure waves. Therefore an influx of ion currents, respectively fluid motions into the elastic neuronal cells and fibres also induce impulses. This motion of charge carriers are measured by voltage devices as oscillations or action potentials, but the voltage changes may be an epiphenomenon of the (mechanical) impulses. Impulse waves can have a high speed. As stiffer or inelastic a tube wall, the greater is the speed of the impulse. Myelin sheaths cause a significant stiffening of the nerve fibre wall and myelinated fibres have a conduction velocity up to 120 m/s. The influx of fluid at the nodes of Ranvier intensifies periodically the impulse wave in the nerve fibres. The authors suggest that also the muscle end-plate acts as a conductor of axonal impulses to the inner of the muscle fibres and that the exocytosis of acetylcholine into the synaptic cleft may be an amplifier of the axonal impulse. It is discussed that intracellular actin filaments may also influence motions at the neuronal membrane. Many sensory nerve cells are excited due to exogenous or endogenous mechanical impulses. It may plausible that such impulses are conducted directly to the sensory nerve cell bodies in the dorsal root ganglia without the transformation in electric energy. Excitation conduction happens without noteworthy energy consumption because the flow of ion currents through the membranes takes place equivalent to the concentration gradient. Impulse waves cause short extensions of the lipid membranes of the cell- and fibres walls and therefore they can induce opening and closing of the included ion channels. This mechanism acts to "voltage gated" and "ligand-gated" channels likewise. The concept of neuronal impulses can be helpful to the understanding of other points of neurophysiology or neuronal diseases. This includes
10. High-resolution spectroscopy of jet-cooled 1,1 '-diphenylethylene: electronically excited and ionic states of a prototypical cross-conjugated system
NARCIS (Netherlands)
Smolarek, S.; Vdovin, A.; Rijs, A.; van Walree, C.A.; Zgierski, M.Z.; Buma, W.J.
2011-01-01
The photophysics of a prototypical cross-conjugated π-system, 1,1′-diphenylethylene, have been studied using high-resolution resonance enhanced multiphoton ionization excitation spectroscopy and zero kinetic energy photoelectron spectroscopy, in combination with advanced ab initio calculations. We
11. Dynamics of Solid Body in Magnetic Suspension under Periodic Excitation
Directory of Open Access Journals (Sweden)
A. M. Gouskov
2017-01-01
Full Text Available The article studies dynamics of ferromagnetic body in hybrid magnetic suspension (HMS. The body is supposed to have one degree of freedom and a nonlinear magnetic force dependence on the current and displacement. The magnetic force induced in the HMS is divided into a passive component and an active one. Specifying the law of current variation in the coil allows us to generate nonlinear oscillations under electromagnet action. To provide periodic excitation the appropriate law of the current variation in the electromagnet coil is proposed. The mathematical model includes external periodic step-excitation. The equation of motion is formed. The scales of similarity are highlighted in the system, and the equation of motion is reduced to dimensionless form.The motion dynamics is studied numerically. The relaxation method was used to determine the periodic motions at different values of dimensionless frequency of the electromagnet excitation as well as to estimate the influence of other dimensionless parameters on the system dynamics. The amplitude-frequency curve analysis allows us to come to conclusion that the nature of system nonlinearity is rigid. Adding the external periodic step-excitation leads to the qualitative change in the nature of movement. This points to the occurrence of bifurcation.
12. Classification of a Supersolid: Trial Wavefunctions, Symmetry Breakings and Excitation Spectra
Science.gov (United States)
Chen, Yu; Ye, Jinwu; Tian, Guangshan
2012-11-01
A state of matter is characterized by its symmetry breaking and elementary excitations. A supersolid is a state which breaks both translational symmetry and internal U(1) symmetry. Here, we review some past and recent works in phenomenological Ginsburg-Landau theories, ground state trial wavefunctions and microscopic numerical calculations. We also write down a new effective supersolid Hamiltonian on a lattice. The eigenstates of the Hamiltonian contains both the ground state wavefunction and all the excited states (supersolidon) wavefunctions. We contrast various kinds of supersolids in both continuous systems and on lattices, both condensed matter and cold atom systems. We provide additional new insights in studying their order parameters, symmetry breaking patterns, the excitation spectra and detection methods.
13. Amplitudes and state parameters from ion- and atom-atom excitation processes
International Nuclear Information System (INIS)
Andersen, T.; Horsdal-Pedersen, E.
1984-01-01
This chapter examines single collisions between two atomic species, one of which is initially in a 1 S state (there is only one initial spin channel). The collisions are characterized by a definite scattering plane and a definite orientation. Topics considered include an angular correlation between scattered particles and autoionization electrons or polarized photons emitted from states excited in atomic collisions (photon emission, electron emission, selectivity excited target atoms), experimental methods for obtaining information on the alignment and orientation parameters of atoms or ions excited in specific collisions, results of experiments and numerical calculations (quasi-oneelectron systems, He + -He collisions, other collision systems), and future aspects and possible applications of the polarizedphoton, scattered-particle coincidence techniques to atomic spectroscopy
14. Theory of nuclear excitation by electron capture for heavy ions
International Nuclear Information System (INIS)
Palffy, Adriana; Scheid, Werner; Harman, Zoltan
2006-01-01
We investigate the resonant process of nuclear excitation by electron capture (NEEC), in which a continuum electron is captured into a bound state of an ion with the simultaneous excitation of the nucleus. In order to derive the cross section a Feshbach projection operator formalism is introduced. Nuclear states and transitions are described by a nuclear collective model and making use of experimental data. Transition rates and total cross sections for NEEC followed by the radiative decay of the excited nucleus are calculated for various heavy-ion collision systems
15. Study of the excitation mechanisms of the second positive system in the negative glow of a N{sub 2}-Ar discharge
Energy Technology Data Exchange (ETDEWEB)
Isola, L; Lopez, M; Gomez, B J, E-mail: [email protected] [Instituto de Fisica Rosario (CONICET-UNR) 27 Febrero 210 Bis. (S2000EZP) Rosario (Argentina)
2011-09-21
In an Ar-N{sub 2} discharge, the high excitation transfer from Ar({sup 3}P{sub 2,0}) to N{sub 2} produces an overpopulation of the high rotational levels of the bands of the second positive system (SPS), and so the spectra interpretation is not straightforward. This paper presents a fit function for the SPS bands measured in Ar-N{sub 2}, which allows us to study the excitation process contributions to the N{sub 2}(C) level. The procedure was tested in the negative glow of a pulsed Ar-N{sub 2} discharge at a pressure of 2.5 Torr, for different mixture concentrations. In this discharge, through the fitting, it was possible to calculate the variation of the N{sub 2}(C) densities produced by different excitation processes as well as the variation of Ar metastable density.
16. Multi-frequency excitation
KAUST Repository
2016-01-01
Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected
17. Excited-state quantum phase transitions in systems with two degrees of freedom: Level density, level dynamics, thermal properties
International Nuclear Information System (INIS)
Stránský, Pavel; Macek, Michal; Cejnar, Pavel
2014-01-01
Quantum systems with a finite number of freedom degrees f develop robust singularities in the energy spectrum of excited states as the system’s size increases to infinity. We analyze the general form of these singularities for low f, particularly f=2, clarifying the relation to classical stationary points of the corresponding potential. Signatures in the smoothed energy dependence of the quantum state density and in the flow of energy levels with an arbitrary control parameter are described along with the relevant thermodynamical consequences. The general analysis is illustrated with specific examples of excited-state singularities accompanying the first-order quantum phase transition. -- Highlights: •ESQPTs found in infinite-size limit of systems with low numbers of freedom degrees f. •ESQPTs related to non-analytical evolutions of classical phase–space properties. •ESQPT signatures analyzed for general f, particularly f=2, extending known case f=1. •ESQPT signatures identified in smoothened density and flow of energy spectrum. •ESQPTs shown to induce a new type of thermodynamic anomalies
18. Seismic enhancement of multi-span continuous bridges subjected to three-directional excitations
Science.gov (United States)
Aryan, H.; Ghassemieh, M.
2015-04-01
Considering the seismic ground motions as the excitations in only two principal horizontal directions of the bridges and ignoring the third vertical direction is a disregard for the seismic conditions of the region and the bridge distance from epicenter. Numerous cases of substantial damages have been reported among the bridges tremendously suffered from being exposed to the simultaneous three-directional seismic ground motions. Besides the significant compression and tension damages in the columns due to the presence of vertical excitation, it could lead to unexpected shear and flexural failures in the columns and other components as well. Because the axial force variation in the columns due to three-directional excitations, could affect the demands and capacities of the bridge’s components. With respect to this issue, several studies on the bridge damages during the earthquakes have urged researchers to offer efficient methods for bridges handling of the three-directional seismic excitations. Thus, this paper presents and evaluates a superelastic based system for designing as well as retrofitting the multi-span continuous (MSC) bridges that can cope with two- and three-directional seismic excitations. Efficiency evaluation of the proposed system is conducted through various nonlinear time history analyses on a three-dimensional model of a detailed MSC bridge using a suite of developed ground motions for the bridge region. Also, all the analyses are fulfilled based on variation of one influential design characteristic of the proposed system in order to achieve the optimal design. Several pertinent assessment parameters are used during the evaluation of the proposed system. Finally, the efficiency of the new system subjected to the vertical and horizontal seismic excitations is confirmed according to reduction of the bridge responses and improvement in nonlinear performance of the columns in comparison with the as-built bridge results.
19. Excited charmed mesons
International Nuclear Information System (INIS)
Butler, J.N.; Shukla, S.
1995-05-01
The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one
20. Nonlinear characteristics of the rotating exciter system of power plant generators in case of electricity accidents; Transientes Verhalten des rotierenden Erregersystems von Kraftwerksgeneratoren bei elektrischen Stoerfaellen
Energy Technology Data Exchange (ETDEWEB)
2006-05-09
Different types of exciter are used for voltage supply to the synchronous generators of power stations depending on the required power and design. The exciter system of the generator, which as a rule consists syncronous motors and commutators, is commonly modeled in conventional models by control units with nonlinear characteristics which do not give an accurate picture of the dynamic processes inside the exciter motor. It was not possible to assess the component loads of the exciter components and the physical characteristics within the exciter system. In this study, a brushless exciter for the grid-connected synchronous generator was investigated which consists of two synchronous motors as primary and secondary exciter and two commutator bridges. A dynamic simulation model was developed for calculating the interactions between the grid, generator and exciter unit in consideration of electromagnetic and galvanic coupling. For this, the normal control units were replaced by physical components of the exciter system, i.e. electric exciter motors and commutators. The study was carried out using an enhanced version of the Siemens NETOMAC software, which provided information on the loads on the exciter components in case of internal and external failures. In particular, loads in coils and commutators were calculated that could not be measured before. The findings enable more accurate dimensioning of the exciter unit making it more fail-safe, and the protective systems can be adjusted more accurately. One important result of the investigation was the identification of all dynamic processes going on between the exciter motors, commutators, generator and grid induced by external and internal failures. (orig.) [German] Zur Spannungsversorgung der Synchrongeneratoren in Kraftwerken werden je nach Leistungsanforderung und Baukonzept unterschiedliche Erregereinrichtungen verwendet. Das Erregersystem des Generators, das in der Regel aus Erregersynchronmaschinen und
1. Electric quadrupole excitation of the first excited state of 11B
International Nuclear Information System (INIS)
Fewell, M.P.; Spear, R.H.; Zabel, T.H.; Baxter, A.M.
1980-02-01
The Coulomb excitation of backscattered 11 B projectiles has been used to measure the reduced E2 transition probability B(E2; 3/2 - →1/2 - ) between the 3/2 - ground state and the 1/2 - first excited state of 11 B. It is found that B(E2; 3/2 - →1/2 - ) = 2.1 +- 0.4 e 2 fm 4 , which agrees with shell-model predictions but is a factor of 10 larger than the prediction of the core-excitation model
2. Proposition for sensorless self-excitation by a piezoelectric device
Science.gov (United States)
Tanaka, Y.; Kokubun, Y.; Yabuno, H.
2018-04-01
In this paper, we propose a method to realize self-excitation in an oscillator actuated by a piezoelectric device without a sensor. In general, the positive feedback associated with the oscillator velocity causes the self-excitation. Instead of measuring the velocity with a sensor, we utilize the electro-mechanical coupling effect in the oscillator and piezoelectric device. We drive the piezoelectric device with a current proportional to the linear combination of the voltage across the terminals of the piezoelectric device and its differential voltage signal. Then, the oscillator with the piezoelectric device behaves like a third-order system, which has three eigenvalues. The self-excitation can be realized because appropriate feedback gains can set two of the eigenvalues to be conjugate complex roots with a positive real part and the other eigenvalue to be a negative real root. To confirm the validity of the proposed method, we experimentally demonstrated the sensorless self-excitation and, as an application example, carried out mass sensing in a sensorless self-excited macrocantilever.
3. MEMS Logic Using Mixed-Frequency Excitation
KAUST Repository
2017-06-22
We present multi-function microelectromechanical systems (MEMS) logic device that can perform the fundamental logic gate AND, OR, universal logic gates NAND, NOR, and a tristate logic gate using mixed-frequency excitation. The concept is based on exciting combination resonances due to the mixing of two or more input signals. The device vibrates at two steady states: a high state when the combination resonance is activated and a low state when no resonance is activated. These vibration states are assigned to logical value 1 or 0 to realize the logic gates. Using ac signals to drive the resonator and to execute the logic inputs unifies the input and output wave forms of the logic device, thereby opening the possibility for cascading among logic devices. We found that the energy consumption per cycle of the proposed logic resonator is higher than those of existing technologies. Hence, integration of such logic devices to build complex computational system needs to take into consideration lowering the total energy consumption. [2017-0041
4. Charge transfer excitations from exact and approximate ensemble Kohn-Sham theory
Science.gov (United States)
Gould, Tim; Kronik, Leeor; Pittalis, Stefano
2018-05-01
By studying the lowest excitations of an exactly solvable one-dimensional soft-Coulomb molecular model, we show that components of Kohn-Sham ensembles can be used to describe charge transfer processes. Furthermore, we compute the approximate excitation energies obtained by using the exact ensemble densities in the recently formulated ensemble Hartree-exchange theory [T. Gould and S. Pittalis, Phys. Rev. Lett. 119, 243001 (2017)]. Remarkably, our results show that triplet excitations are accurately reproduced across a dissociation curve in all cases tested, even in systems where ground state energies are poor due to strong static correlations. Singlet excitations exhibit larger deviations from exact results but are still reproduced semi-quantitatively.
5. Ultrafast electronic relaxation of excited state vitamin B12 in the gas phase
International Nuclear Information System (INIS)
Shafizadeh, Niloufar; Poisson, Lionel; Soep, Benoit
2008-01-01
The time evolution of electronically excited vitamin B 12 (cyanocobalamin) has been observed for the first time in the gas phase. It reveals an ultrafast decay to a state corresponding to metal excitation. This decay is interpreted as resulting from a ring to metal electron transfer. This opens the observation of the excited state of other complex biomimetic systems in the gas phase, the key to the characterisation of their complex evolution through excited electronic states
6. Springing response due to bidirectional wave excitation
DEFF Research Database (Denmark)
Vidic-Perunovic, Jelena
2005-01-01
theories deal with the unidirectional wave excitation. This is quite standard. The problem is how to include more than one directional wave systems described by a wave spectrum with arbitrary heading. The main objective of the present work has been to account for the additional second-order springing......-linear (second order) high frequency springing analyses with unidirectional wave excitation are much more scattered. Some of the reasons are different level of wave excitation accounted in the different Executive Summary ivtheories, inclusion of additional hydrodynamic phenomena e.g. slamming in the time...... because, to the author's knowledge, this is the first time that the wave data were collected simultaneously with stress records on the deck of the ship. This is highly appreciated because one can use the precise input and not only the most probable sea state statistics. The actual picture of the sea waves...
7. DESIGN METHODOLOGY OF SELF-EXCITED ASYNCHRONOUS GENERATOR
Directory of Open Access Journals (Sweden)
Berzan V.
2012-04-01
Full Text Available The paper sets out the methodology of designing an asynchronous generator with capacitive self-excitation. It is known that its design is possible on the basis of serial synchronous motor with squirrel cage rotor. With this approach, the design reworked only the stator winding of electrical machines, making it cost-effectively implement the creation of the generator. Therefore, the methodology for the design, optimization calculations, the development scheme and the stator winding excitation system gain, not only of practical interest, and may also be useful for specialists in the field of electrical machines in the design of asynchronous generators.
8. Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections
Energy Technology Data Exchange (ETDEWEB)
Országh, Juraj; Danko, Marián; Čechvala, Peter; Matejčík, Štefan, E-mail: [email protected] [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F-2, 842 48 Bratislava (Slovakia)
2017-05-20
The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.
9. Dynamics of excited instantons in the system of forced Gursey nonlinear differential equations
Energy Technology Data Exchange (ETDEWEB)
Aydogmus, F., E-mail: [email protected] [Istanbul University, Department of Physics, Faculty of Science (Turkey)
2015-02-15
The Gursey model is a 4D conformally invariant pure fermionic model with a nonlinear spinor self-coupled term. Gursey proposed his model as a possible basis for a unitary description of elementary particles following the “Heisenberg dream.” In this paper, we consider the system of Gursey nonlinear differential equations (GNDEs) formed by using the Heisenberg ansatz. We use it to understand how the behavior of spinor-type Gursey instantons can be affected by excitations. For this, the regular and chaotic numerical solutions of forced GNDEs are investigated by constructing their Poincaré sections in phase space. A hierarchical cluster analysis method for investigating the forced GNDEs is also presented.
10. Modeling And Control Of Excitation And Governor Based On PSO For MHPP
Directory of Open Access Journals (Sweden)
2013-07-01
Full Text Available This paper presents the modeling and control of the excitation system via the automatic voltage regulator (AVR and governor system through the automatic generation control (AGC or frequency load control (FLC to improve stability on a micro hydro power plant (MHPP. Three main parts of the generation system are synchronous generator, AVR/excitation, AGC modelled linearly. Generator is modelled by a single machine connected to infinite bus (SMIB which is equipped by AVR and excitation linear model. Excitation control system made ??by optimizing the gain of the AVR (KA and the governor with the gain of the AGC (Ki. Optimization is done using the method improved particle swam optimization (IPSO. The main purpose of setting the gain of the AVR-AGC is to stabilize the oscillation frequency of the MHPP is connected to an infinite bus. Simulations are conducted by inputting step function with 5% load fluctuations as a representation of dynamic load. The simulation results show that the proposed method effectively raises the level of electromechanical damping oscillations the SMIB by generating the comprehensive damping index (CDI is minimum.
11. Excitation spectrum of Heisenberg spin ladders
International Nuclear Information System (INIS)
Barnes, T.; Dagotto, E.; Riera, J.; Swanson, E.S.
1993-01-01
Heisenberg antiferromagnetic spin ''ladders'' (two coupled spin chains) are low-dimensional magnetic systems which for S=1/2 interpolate between half-integer-spin chains, when the chains are decoupled, and effective integer-spin one-dimensional chains in the strong-coupling limit. The spin-1/2 ladder may be realized in nature by vanadyl pyrophosphate, (VO) 2 P 2 O 7 . In this paper we apply strong-coupling perturbation theory, spin-wave theory, Lanczos techniques, and a Monte Carlo method to determine the ground-state energy and the low-lying excitation spectrum of the ladder. We find evidence of a nonzero spin gap for all interchain couplings J perpendicular >0. A band of spin-triplet excitations above the gap is also analyzed. These excitations are unusual for an antiferromagnet, since their long-wavelength dispersion relation behaves as (k-k 0 ) 2 (in the strong-coupling limit J perpendicular much-gt J, where J is the in-chain antiferromagnetic coupling). Their band is folded, with a minimum energy at k 0 =π, and a maximum between k 1 =π/2 (for J perpendicular =0) and 0 (for J perpendicular =∞). We also give numerical results for the dynamical structure factor S(q,ω), which can be determined in neutron scattering experiments. Finally, possible experimental techniques for studying the excitation spectrum are discussed
12. Negative ion formation in collisions involving excited alkali atoms
International Nuclear Information System (INIS)
Cheret, M.
1988-01-01
Ion-pair production is considered as the prototype of the crossing problem between potential energy curves. In general an alkali atom is one of the reactants the other being an halogen, hydrogen atom or molecule. Experimental results are generally analyzed in the framework of the Landau-Zener-Stuekelberg theory, ionization potential and electron affinity, being the most important parameters. In order to vary these parameters over a wide range two experimental works have been devoted to systems of excited alkali atoms colliding with ground state alkali atoms. In the first study Rb atoms are excited to various ns or nd states from Rb(5d) to Rb(9s) in a cell. The second study is devoted to the Na(3p)-Na(3s) system, in this study also the possibility of creating excited negative ions (Na - (3s3p)) has been investigated. These results are presented and analyzed. Finally further developments of the subject are suggested. 17 refs.; 8 figs.; 1 table
13. Nuclear fission fragment excitation of electronic transition laser media
International Nuclear Information System (INIS)
Lorents, D.C.; McCusker, M.V.; Rhodes, C.K.
1976-01-01
The properties of high energy electronic transition lasers excited by fission fragments are expanded. Specific characteristics of the media including density, excitation rates, wavelength, kinetics, fissile material, scale size, and medium uniformity are assessed. The use of epithermal neutrons, homogeneously mixed fissile material, and special high cross section nuclear isotopes to optimize coupling of the energy to the medium are shown to be important considerations maximizing the scale size, energy deposition, and medium uniformity. A performance limit point of approximately 1000 J/l in approximately 100 μs pulses is established for a large class of systems operating in the near ultraviolet and visible spectral regions. It is demonstrated that e-beam excitation can be used to simulate nuclear pumping conditions to facilitate the search for candidate media. Experimental data for the kinetics of a XeF* laser operating in Ar/Xe/F 2 /UF 6 mixtures are given. These reactor-pumped systems are suitable for scaling to volumes on the order of (meters) 3
14. Photo-excitation of carotenoids causes cytotoxicity via singlet oxygen production
International Nuclear Information System (INIS)
Yoshii, Hiroshi; Yoshii, Yukie; Asai, Tatsuya; Furukawa, Takako; Takaichi, Shinichi; Fujibayashi, Yasuhisa
2012-01-01
Highlights: ► Some photo-excited carotenoids have photosensitizing ability. ► They are able to produce ROS. ► Photo-excited fucoxanthin can produce singlet oxygen through energy transfer. -- Abstract: Carotenoids, natural pigments widely distributed in algae and plants, have a conjugated double bond system. Their excitation energies are correlated with conjugation length. We hypothesized that carotenoids whose energy states are above the singlet excited state of oxygen (singlet oxygen) would possess photosensitizing properties. Here, we demonstrated that human skin melanoma (A375) cells are damaged through the photo-excitation of several carotenoids (neoxanthin, fucoxanthin and siphonaxanthin). In contrast, photo-excitation of carotenoids that possess energy states below that of singlet oxygen, such as β-carotene, lutein, loroxanthin and violaxanthin, did not enhance cell death. Production of reactive oxygen species (ROS) by photo-excited fucoxanthin or neoxanthin was confirmed using a reporter assay for ROS production with HeLa Hyper cells, which express a fluorescent indicator protein for intracellular ROS. Fucoxanthin and neoxanthin also showed high cellular penetration and retention. Electron spin resonance spectra using 2,2,6,6-tetramethil-4-piperidone as a singlet oxygen trapping agent demonstrated that singlet oxygen was produced via energy transfer from photo-excited fucoxanthin to oxygen molecules. These results suggest that carotenoids such as fucoxanthin, which are capable of singlet oxygen production through photo-excitation and show good penetration and retention in target cells, are useful as photosensitizers in photodynamic therapy for skin disease.
15. Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Butorin, S.M.; Guo, J.; Magnuson, M. [Uppsala Univ. (Sweden)] [and others
1997-04-01
Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state.
16. Low-energy d-d excitations in MnO studied by resonant x-ray fluorescence spectroscopy
International Nuclear Information System (INIS)
Butorin, S.M.; Guo, J.; Magnuson, M.
1997-01-01
Resonant soft X-ray emission spectroscopy has been demonstrated to possess interesting abilities for studies of electronic structure in various systems, such as symmetry probing, alignment and polarization dependence, sensitivity to channel interference, etc. In the present abstract the authors focus on the feasibility of resonant soft X-ray emission to probe low energy excitations by means of resonant electronic X-ray Raman scattering. Resonant X-ray emission can be regarded as an inelastic scattering process where a system in the ground state is transferred to a low excited state via a virtual core excitation. The energy closeness to a core excitation of the exciting radiation enhances the (generally) low probability for inelastic scattering at these wavelengths. Therefore soft X-ray emission spectroscopy (in resonant electronic Raman mode) can be used to study low energy d-d excitations in transition metal systems. The involvement of the intermediate core state allows one to use the selection rules of X-ray emission, and the appearance of the elastically scattered line in the spectra provides the reference to the ground state
17. Electron-helium S-wave model benchmark calculations. II. Double ionization, single ionization with excitation, and double excitation
Science.gov (United States)
Bartlett, Philip L.; Stelbovics, Andris T.
2010-02-01
The propagating exterior complex scaling (PECS) method is extended to all four-body processes in electron impact on helium in an S-wave model. Total and energy-differential cross sections are presented with benchmark accuracy for double ionization, single ionization with excitation, and double excitation (to autoionizing states) for incident-electron energies from threshold to 500 eV. While the PECS three-body cross sections for this model given in the preceding article [Phys. Rev. A 81, 022715 (2010)] are in good agreement with other methods, there are considerable discrepancies for these four-body processes. With this model we demonstrate the suitability of the PECS method for the complete solution of the electron-helium system.
18. Strategies to enhance the excitation energy-transfer efficiency in a light-harvesting system using the intra-molecular charge transfer character of carotenoids
Energy Technology Data Exchange (ETDEWEB)
Yukihira, Nao [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Sugai, Yuko [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Fujiwara, Masazumi [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan; Kosumi, Daisuke [Institute of Pulsed Power Science; Kumamoto University; Kumamoto; Japan; Iha, Masahiko [South Product Co. Ltd.; Uruma-shi; Japan; Sakaguchi, Kazuhiko [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Katsumura, Shigeo [Department of Chemistry; Graduate School of Science; Osaka City University; Osaka 558-8585; Japan; Gardiner, Alastair T. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Cogdell, Richard J. [Glasgow Biomedical Research Centre; University of Glasgow; 126 University Place; Glasgow, G12 8QQ; UK; Hashimoto, Hideki [Department of Applied Chemistry for Environment; School of Science and Technology; Kwansei Gakuin University; Sanda; Japan
2017-01-01
Fucoxanthin is a carotenoid that is mainly found in light-harvesting complexes from brown algae and diatoms. Due to the presence of a carbonyl group attached to polyene chains in polar environments, excitation produces an excited intra-molecular charge transfer. This intra-molecular charge transfer state plays a key role in the highly efficient (~95%) energy-transfer from fucoxanthin to chlorophyllain the light-harvesting complexes from brown algae. In purple bacterial light-harvesting systems the efficiency of excitation energy-transfer from carotenoids to bacteriochlorophylls depends on the extent of conjugation of the carotenoids. In this study we were successful, for the first time, in incorporating fucoxanthin into a light-harvesting complex 1 from the purple photosynthetic bacterium,Rhodospirillum rubrumG9+ (a carotenoidless strain). Femtosecond pump-probe spectroscopy was applied to this reconstituted light-harvesting complex in order to determine the efficiency of excitation energy-transfer from fucoxanthin to bacteriochlorophyllawhen they are bound to the light-harvesting 1 apo-proteins.
19. An Improved Multidimensional MPA Procedure for Bidirectional Earthquake Excitations
Directory of Open Access Journals (Sweden)
Feng Wang
2014-01-01
Full Text Available Presently, the modal pushover analysis procedure is extended to multidimensional analysis of structures subjected to multidimensional earthquake excitations. an improved multidimensional modal pushover analysis (IMMPA method is presented in the paper in order to estimate the response demands of structures subjected to bidirectional earthquake excitations, in which the unidirectional earthquake excitation applied on equivalent SDOF system is replaced by the direct superposition of two components earthquake excitations, and independent analysis in each direction is not required and the application of simplified superposition formulas is avoided. The strength reduction factor spectra based on superposition of earthquake excitations are discussed and compared with the traditional strength reduction factor spectra. The step-by-step procedure is proposed to estimate seismic demands of structures. Two examples are implemented to verify the accuracy of the method, and the results of the examples show that (1 the IMMPA method can be used to estimate the responses of structure subjected to bidirectional earthquake excitations. (2 Along with increase of peak of earthquake acceleration, structural response deviation estimated with the IMMPA method may also increase. (3 Along with increase of the number of total floors of structures, structural response deviation estimated with the IMMPA method may also increase.
20. Range-separated density-functional theory for molecular excitation energies
International Nuclear Information System (INIS)
Rebolini, E.
2014-01-01
Linear-response time-dependent density-functional theory (TDDFT) is nowadays a method of choice to compute molecular excitation energies. However, within the usual adiabatic semi-local approximations, it is not able to describe properly Rydberg, charge-transfer or multiple excitations. Range separation of the electronic interaction allows one to mix rigorously density-functional methods at short range and wave function or Green's function methods at long range. When applied to the exchange functional, it already corrects most of these deficiencies but multiple excitations remain absent as they need a frequency-dependent kernel. In this thesis, the effects of range separation are first assessed on the excitation energies of a partially-interacting system in an analytic and numerical study in order to provide guidelines for future developments of range-separated methods for excitation energy calculations. It is then applied on the exchange and correlation TDDFT kernels in a single-determinant approximation in which the long-range part of the correlation kernel vanishes. A long-range frequency-dependent second-order correlation kernel is then derived from the Bethe-Salpeter equation and added perturbatively to the range-separated TDDFT kernel in order to take into account the effects of double excitations. (author)
1. Multipurpose exciter with low phase noise
Science.gov (United States)
Conroy, B.; Le, D.
1989-01-01
Results of an effort to develop a lower-cost exciter with high stability, low phase noise, and controllable phase and frequency for use in Deep Space Network and Goldstone Solar System Radar applications are discussed. Included is a discussion of the basic concept, test results, plans, and concerns.
2. Melnikov's criteria, parametric control of chaos, and stationary chaos occurrence in systems with asymmetric potential subjected to multiscale type excitation.
Science.gov (United States)
Kwuimy, C A Kitio; Nataraj, C; Litak, G
2011-12-01
We consider the problems of chaos and parametric control in nonlinear systems under an asymmetric potential subjected to a multiscale type excitation. The lower bound line for horseshoes chaos is analyzed using the Melnikov's criterion for a transition to permanent or transient nonperiodic motions, complement by the fractal or regular shape of the basin of attraction. Numerical simulations based on the basins of attraction, bifurcation diagrams, Poincaré sections, Lyapunov exponents, and phase portraits are used to show how stationary dissipative chaos occurs in the system. Our attention is focussed on the effects of the asymmetric potential term and the driven frequency. It is shown that the threshold amplitude ∣γ(c)∣ of the excitation decreases for small values of the driven frequency ω and increases for large values of ω. This threshold value decreases with the asymmetric parameter α and becomes constant for sufficiently large values of α. γ(c) has its maximum value for asymmetric load in comparison with the symmetric load. Finally, we apply the Melnikov theorem to the controlled system to explore the gain control parameter dependencies.
3. Semi-active control of a cable-stayed bridge under multiple-support excitations.
Science.gov (United States)
Dai, Ze-Bing; Huang, Jin-Zhi; Wang, Hong-Xia
2004-03-01
This paper presents a semi-active strategy for seismic protection of a benchmark cable-stayed bridge with consideration of multiple-support excitations. In this control strategy, Magnetorheological (MR) dampers are proposed as control devices, a LQG-clipped-optimal control algorithm is employed. An active control strategy, shown in previous researches to perform well at controlling the benchmark bridge when uniform earthquake motion was assumed, is also used in this study to control this benchmark bridge with consideration of multiple-support excitations. The performance of active control system is compared to that of the presented semi-active control strategy. Because the MR fluid damper is a controllable energy- dissipation device that cannot add mechanical energy to the structural system, the proposed control strategy is fail-safe in that bounded-input, bounded-output stability of the controlled structure is guaranteed. The numerical results demonstrated that the performance of the presented control design is nearly the same as that of the active control system; and that the MR dampers can effectively be used to control seismically excited cable-stayed bridges with multiple-support excitations.
4. Excited-state dynamics of acetylene excited to individual rotational level of the V04K01 subband
Science.gov (United States)
Makarov, Vladimir I.; Kochubei, Sergei A.; Khmelinskii, Igor V.
2006-01-01
Dynamics of the IR emission induced by excitation of the acetylene molecule using the (32Ka0,1,2,ÃAu1←41la1,X˜Σg+1) transition was investigated. The observed IR emission was assigned to transitions between the ground-state vibrational levels. Acetylene fluorescence quenching induced by external electric and magnetic fields acting upon the system prepared using the (34Ka1,ÃAu1←00la0,X˜Σg+1) excitation was also studied. External electric field creates an additional radiationless pathway to the ground-state levels, coupling levels of the ÃAu1 excited state to the quasiresonant levels of the X˜Σg+1 ground state. The level density of the ground state in the vicinity of the excited state is very high, thus the electric-field-induced transition is irreversible, with the rate constant described by the Fermi rule. Magnetic field alters the decay profile without changing the fluorescence quantum yield in collisionless conditions. IR emission from the CCH transient was detected, and was also affected by the external electric and magnetic fields. Acetylene predissociation was demonstrated to proceed by the direct S1→S0 mechanism. The results were explained using the previously developed theoretical approach, yielding values of the relevant model parameters.
5. Localized excitations in superconducting point contacts: probing the Andreev doublet
International Nuclear Information System (INIS)
Bretheau, L.
2013-01-01
The Josephson effect describes the coherent coupling between superconductors and the resulting supercurrent. Microscopically, it arises from the existence of discrete quasiparticle states, localized at the weak link, the Andreev bound states. They come in doublets in each conduction channel of the weak link, with energies symmetric about the Fermi energy and opposite supercurrents. Each Andreev doublet gives rise to four states: the ground state |-> and the excited state |+>, with even parity, and the excited odd states |↑> and |↓>. Is it possible to address and control Andreev doublets? This thesis describes two sets of experiments designed to answer this question using the most basic Josephson element, a one-atom contact between two superconducting electrodes. In a first experiment, we have observed and characterized the excited odd states |↑> and |↓>. As expected for a spin-degenerate system, they do not carry supercurrent. In this experiment the excitation was uncontrolled and resulted from trapping of spurious quasiparticles. We have measured the lifetime of the odd states: under some condition, it is found to exceed 100 μs. The second experiment is a photon-absorption spectroscopy of the Andreev doublet. It was performed by using a Josephson junction as an integrated on-chip microwave emitter and detector. The observed Andreev transitions correspond to excitation from the ground state |->to the excited even state |+>, and are well accounted for by our quantum model. This result opens the way to coherent manipulation of this two level system. The direct observation of the excited Andreev state, either by quasiparticle-injection or photon-absorption, strongly supports the mesoscopic theory of the Josephson effect. It shows that in addition to the phase difference, each channel of a Josephson weak link possesses an internal fermionic degree of freedom. It could be used to code information in a novel type of superconducting qubit. (author) [fr
6. Excitation of solar and stellar oscillations
International Nuclear Information System (INIS)
Baudin, Frederic
2009-01-01
In this report for an Accreditation to Supervise Research (HDR), and after an introduction which outlines the potential of helio-seismology, the author addresses the problem of excitation and amplitude of stellar oscillations with respect to their most important aspects, i.e. the theoretical framework of the present understanding of excitation mechanisms, and instrumental influences on measurements which are used to assess excitation rates, the difficulty to perform these measurements, and their analysis in some various cases. Thus, the author addresses excitation mechanisms of stellar oscillation (stochastic excitation, opacity- related excitation, and other excitation mechanisms), the excitation of solar modes (observation and theoretical predictions, influence of magnetic phenomena, solar g modes), and the excitation of modes in other stars (solar-type pulsators, red giants, and not so conventional pulsators such as HD180642 and Be stars like HD49330)
7. Mixed frequency excitation of an electrostatically actuated resonator
KAUST Repository
Ramini, Abdallah
2015-04-24
We investigate experimentally and theoretically the dynamics of a capacitive resonator under mixed frequency excitation of two AC harmonic signals. The resonator is composed of a proof mass suspended by two cantilever beams. Experimental measurements are conducted using a laser Doppler vibrometer to reveal the interesting dynamics of the system when subjected to two-source excitation. A nonlinear single-degree-of-freedom model is used for the theoretical investigation. The results reveal combination resonances of additive and subtractive type, which are shown to be promising to increase the bandwidth of the resonator near primary resonance frequency. Our results also demonstrate the ability to shift the combination resonances to much lower or much higher frequency ranges. We also demonstrate the dynamic pull-in instability under mixed frequency excitation. © 2015 Springer-Verlag Berlin Heidelberg
8. Excitation in the radiation chemistry of inorganic gases
International Nuclear Information System (INIS)
Willis, C.; Boyd, A.W.
1976-01-01
Gas phase radiation chemistry yield data and electron impact cross-section data are used to derive excitation mechanisms and to discuss the role of excited states in the radiation chemistry of O 2 , N 2 , N 2 O, CO, CO 2 , H 2 S, H 2 O and NH 3 . For each of these systems available cross-sections for ionization and neutral excitation are listed, together with relevant reaction rate data and a summary of the radiation chemistry studies at both high and low dose rates. In general, fairly complete mechanisms are derived and further tested by energy balance calculations. In order to present as complete a picture as possible, a summary of rates and products of ion-neutralization reactions is given at the end of the paper. (author)
9. Integrated parallel reception, excitation, and shimming (iPRES).
Science.gov (United States)
Han, Hui; Song, Allen W; Truong, Trong-Kha
2013-07-01
To develop a new concept for a hardware platform that enables integrated parallel reception, excitation, and shimming. This concept uses a single coil array rather than separate arrays for parallel excitation/reception and B0 shimming. It relies on a novel design that allows a radiofrequency current (for excitation/reception) and a direct current (for B0 shimming) to coexist independently in the same coil. Proof-of-concept B0 shimming experiments were performed with a two-coil array in a phantom, whereas B0 shimming simulations were performed with a 48-coil array in the human brain. Our experiments show that individually optimized direct currents applied in each coil can reduce the B0 root-mean-square error by 62-81% and minimize distortions in echo-planar images. The simulations show that dynamic shimming with the 48-coil integrated parallel reception, excitation, and shimming array can reduce the B0 root-mean-square error in the prefrontal and temporal regions by 66-79% as compared with static second-order spherical harmonic shimming and by 12-23% as compared with dynamic shimming with a 48-coil conventional shim array. Our results demonstrate the feasibility of the integrated parallel reception, excitation, and shimming concept to perform parallel excitation/reception and B0 shimming with a unified coil system as well as its promise for in vivo applications. Copyright © 2013 Wiley Periodicals, Inc.
10. Performance Analysis of a Hybrid One-Sided Magnetic Exciter Mounted on a Piezoelectric Stack
Directory of Open Access Journals (Sweden)
A. Nandi
2010-01-01
Full Text Available The present work proposes a non-contact hybrid exciter especially useful for harmonic excitation of lightly damped structures/rotors. In the proposed exciter an electromagnet is placed on a piezoelectric stack and the extension of the piezoelectric stack is made almost equal to the displacement of the structure using a simple tracking control. This largely eliminates stiffness coupling between the structure/rotor and the exciter and non-linearity in the excitation force due to the vibration of the structure/rotor. The stiffness and inertia of the piezoelectric stack is considered in the analysis. A SIMULINK model of the combined structure and the exciter is developed for a full time-domain simulation of the excitation system.
11. Characterization of weakly excited final states by shakedown spectroscopy of laser-excited potassium
International Nuclear Information System (INIS)
Schulz, J.; Heinaesmaeki, S.; Aksela, S.; Aksela, H.; Sankari, R.; Rander, T.; Lindblad, A.; Bergersen, H.; Oehrwall, G.; Svensson, S.; Kukk, E.
2006-01-01
3p shakedown spectra of laser excited potassium atoms as well as direct 3p photoemission of ground state potassium have been studied. These two excitation schemes lead to the same final states and thereby provide a good basis for a detailed study of the 3p 5 (4s3d) 1 configurations of singly ionized potassium and the photoemission processes leading to these configurations. The comparison of direct photoemission from the ground state and conjugate shakedown spectra from 4p 1/2 laser excited potassium made it possible to experimentally determine the character of final states that are only weakly excited in the direct photoemission but have a much higher relative intensity in the shakedown spectrum. Based on considerations of angular momentum and parity conservation the excitation scheme of the final states can be understood
12. Design of excitation signals for active system monitoring in a performance assessment setup
DEFF Research Database (Denmark)
2011-01-01
This paper investigates how the excitation signal should be chosen for a active performance setup. The signal is used in a setup where the main purpose is to detect whether a parameter change of the controller has changed the global performance significantly. The signal has to be able to excite...... the dynamics of the subsystem under investigation both before and after the parameter change. The controller is well know, but there exists no detailed knowledge about the dynamics of the subsystem....
13. Quenching reactions of electronically excited atoms
International Nuclear Information System (INIS)
Setser, D.W.
2001-01-01
The two-body, thermal quenching reactions of electronically excited atoms are reviewed using excited states of Ar, Kr, and Xe atoms as examples. State-specific interstate relaxation and excitation-transfer reactions with atomic colliders are discussed first. These results then are used to discuss quenching reactions of excited-state atoms with diatomic and polyatomic molecules, the latter have large cross sections, and the reactions can proceed by excitation transfer and by reactive quenching. Excited states of molecules are not considered; however, a table of quenching rate constants is given for six excited-state molecules in an appendix
14. Giant resonances on excited states
International Nuclear Information System (INIS)
Besold, W.; Reinhard, P.G.; Toepffer, C.
1984-01-01
We derive modified RPA equations for small vibrations about excited states. The temperature dependence of collective excitations is examined. The formalism is applied to the ground state and the first excited state of 90 Zr in order to confirm a hypothesis which states that not only the ground state but every excited state of a nucleus has a giant resonance built upon it. (orig.)
15. Nano-optical conveyor belt with waveguide-coupled excitation.
Science.gov (United States)
Wang, Guanghui; Ying, Zhoufeng; Ho, Ho-pui; Huang, Ying; Zou, Ningmu; Zhang, Xuping
2016-02-01
We propose a plasmonic nano-optical conveyor belt for peristaltic transport of nano-particles. Instead of illumination from the top, waveguide-coupled excitation is used for trapping particles with a higher degree of precision and flexibility. Graded nano-rods with individual dimensions coded to have resonance at specific wavelengths are incorporated along the waveguide in order to produce spatially addressable hot spots. Consequently, by switching the excitation wavelength sequentially, particles can be transported to adjacent optical traps along the waveguide. The feasibility of this design is analyzed using three-dimensional finite-difference time-domain and Maxwell stress tensor methods. Simulation results show that this system is capable of exciting addressable traps and moving particles in a peristaltic fashion with tens of nanometers resolution. It is the first, to the best of our knowledge, report about a nano-optical conveyor belt with waveguide-coupled excitation, which is very important for scalability and on-chip integration. The proposed approach offers a new design direction for integrated waveguide-based optical manipulation devices and its application in large scale lab-on-a-chip integration.
16. Laser-excited atomic-fluorescence spectrometry with electrothermal tube atomization.
Science.gov (United States)
Vera, J A; Leong, M B; Stevenson, C L; Petrucci, G; Winefordner, J D
1989-12-01
The performance of graphite-tube electrothermal atomizers is evaluated for laser-excited atomic-fluorescence spectrometry for several elements. Three pulsed laser systems are used to pump tunable dye lasers which subsequently are used to excite Pb, Ga, In, Fe, Ir, and Tl atoms in the hot graphite tube. The dye laser systems used are pumped by nitrogen, copper vapour and Nd:YAG lasers. Detection limits in the femtogram and subfemtogram range are typically obtained for all elements. A commercial graphite-tube furnace is important for the successful utilization of the laser-based method when the determination of trace elements is intended, especially when complicated matrices may be present.
17. Excited states
CERN Document Server
Lim, Edward C
1974-01-01
Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab
18. Real-space visualization of remnant Mott gap and magnon excitations.
Science.gov (United States)
Wang, Y; Jia, C J; Moritz, B; Devereaux, T P
2014-04-18
We demonstrate the ability to visualize real-space dynamics of charge gap and magnon excitations in the Mott phase of the single-band Hubbard model and the remnants of these excitations with hole or electron doping. At short times, the character of magnetic and charge excitations is maintained even for large doping away from the Mott and antiferromagnetic phases. Doping influences both the real-space patterns and long timescales of these excitations with a clear carrier asymmetry attributable to particle-hole symmetry breaking in the underlying model. Further, a rapidly oscillating charge-density-wave-like pattern weakens, but persists as a visible demonstration of a subleading instability at half-filling which remains upon doping. The results offer an approach to analyzing the behavior of systems where momentum space is either inaccessible or poorly defined.
19. Saturated excitation of Fluorescence to quantify excitation enhancement in aperture antennas
KAUST Repository
Aouani, Heykel
2012-07-23
Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas. © 2012 Optical Society of America.
20. Saturated excitation of Fluorescence to quantify excitation enhancement in aperture antennas
KAUST Repository
Aouani, Heykel; Hostein, Richard; Mahboub, Oussama; Devaux, Eloï se; Rigneault, Hervé ; Ebbesen, Thomas W.; Wenger, Jé rô me
2012-01-01
Fluorescence spectroscopy is widely used to probe the electromagnetic intensity amplification on optical antennas, yet measuring the excitation intensity amplification is a challenge, as the detected fluorescence signal is an intricate combination of excitation and emission. Here, we describe a novel approach to quantify the electromagnetic amplification in aperture antennas by taking advantage of the intrinsic non linear properties of the fluorescence process. Experimental measurements of the fundamental f and second harmonic 2f amplitudes of the fluorescence signal upon excitation modulation are used to quantify the electromagnetic intensity amplification with plasmonic aperture antennas. © 2012 Optical Society of America.
1. Spike latency and response properties of an excitable micropillar laser
Science.gov (United States)
Selmi, F.; Braive, R.; Beaudoin, G.; Sagnes, I.; Kuszelewicz, R.; Erneux, T.; Barbay, S.
2016-10-01
We present experimental measurements concerning the response of an excitable micropillar laser with saturable absorber to incoherent as well as coherent perturbations. The excitable response is similar to the behavior of spiking neurons but with much faster time scales. It is accompanied by a subnanosecond nonlinear delay that is measured for different bias pump values. This mechanism provides a natural scheme for encoding the strength of an ultrafast stimulus in the response delay of excitable spikes (temporal coding). Moreover, we demonstrate coherent and incoherent perturbations techniques applied to the micropillar with perturbation thresholds in the range of a few femtojoules. Responses to coherent perturbations assess the cascadability of the system. We discuss the physical origin of the responses to single and double perturbations with the help of numerical simulations of the Yamada model and, in particular, unveil possibilities to control the relative refractory period that we recently evidenced in this system. Experimental measurements are compared to both numerical simulations of the Yamada model and analytic expressions obtained in the framework of singular perturbation techniques. This system is thus a good candidate to perform photonic spike processing tasks in the framework of novel neuroinspired computing systems.
2. Optimum design of a Lanchester damper for a viscously damped single degree of freedom system subjected to inertial excitation
Science.gov (United States)
Bapat, V. A.; Prabhu, P.
1980-11-01
The problem of designing an optimum Lanchester damper for a viscously damped single degree of freedom system subjected to inertial harmonic excitation is investigated. Two criteria are used for optimizing the performance of the damper: (i) minimum motion transmissibility; (ii) minimum force transmissibility. Explicit expressions are developed for determining the absorber parameters.
3. Global Analysis of Response in the Piezomagnetoelastic Energy Harvester System under Harmonic and Poisson White Noise Excitations
International Nuclear Information System (INIS)
Yue Xiao-Le; Xu Wei; Zhang Ying; Wang Liang
2015-01-01
The piezomagnetoelastic energy harvester system subjected to harmonic and Poisson white noise excitations is studied by using the generalized cell mapping method. The transient and stationary probability density functions (PDFs) of response based on the global viewpoint are obtained by the matrix analysis method. Monte Carlo simulation results verify the accuracy of this method. It can be observed that evolutionary direction of transient and stationary PDFs is in accordance with the unstable manifold for this system, and a stochastic P-bifurcation occurs as the intensity of Poisson white noise increases. This study presents an efficient numerical tool to solve the stochastic response of a three-dimensional dynamical system and provides a new idea to analyze the energy harvester system. (paper)
4. Excitation and photon decay of giant resonances excited by intermediate energy heavy ions
International Nuclear Information System (INIS)
Bertrand, F.E.; Beene, J.R.
1987-01-01
Inelastic scattering of medium energy heavy ions provides very large cross sections and peak-to-continuum ratios for excitation of giant resonances. For energies above about 50 MeV/nucleon, giant resonances are excited primarily through Coulomb excitation, which is indifferent to isospin, thus providing a good probe for the study of isovector giant resonances. The extremely large cross sections available from heavy ion excitation permit the study of rare decay modes of the giant resonances. In particular, recent measurements have been made of the photon decay of giant resonances following excitation by 22 and 84 MeV/nucleon 17 O projectiles. The singles results at 84 MeV/nucleon yield peak cross sections for the isoscalar giant quadrupole resonance and the isovector giant dipole resonance of approximately 0.8 and 3 barns/sr, respectively. Data on the ground state decay of the isoscalar giant quadrupole and isovector giant dipole resonances are presented and compared with calculations. Decays to low-lying excited states are also discussed. Preliminary results from an experiment to isolate the 208 Pb isovector quadrupole resonance using its gamma decay are presented. 22 refs., 19 figs., 1 tab
5. Electron collisions and internal excitation in stored molecular ion beams
International Nuclear Information System (INIS)
Buhr, H.
2006-01-01
In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He + 2 . The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He + 2 , which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD + is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)
6. Electron collisions and internal excitation in stored molecular ion beams
Energy Technology Data Exchange (ETDEWEB)
Buhr, H.
2006-07-26
In storage ring experiments the role, which the initial internal excitation of a molecular ion can play in electron collisions, and the effect of these collisions on the internal excitation are investigated. Dissociative recombination (DR) and inelastic and super-elastic collisions are studied in the system of He{sup +}{sub 2}. The DR rate coefficient at low energies depends strongly on the initial vibrational excitation in this system. Therefore changes in the DR rate coefficient are a very sensitive probe for changes in the vibrational excitation in He{sup +}{sub 2}, which is used to investigate the effects of collisions with electrons and residual gas species. The low-energy DR of HD{sup +} is rich with resonances from the indirect DR process, when certain initial rotational levels in the molecular ion are coupled to levels in neutral Rydberg states lying below the ion state. Using new procedures for high-resolution electron-ion collision spectroscopy developed here, these resonances in the DR cross section can be measured with high energy sensitivity. This allows a detailed comparison with results of a MQDT calculation in an effort to assign some or all of the resonances to certain intermediate Rydberg levels. (orig.)
7. Elementary spin excitations in ultrathin itinerant magnets
Energy Technology Data Exchange (ETDEWEB)
Zakeri, Khalil, E-mail: [email protected]
2014-12-10
Elementary spin excitations (magnons) play a fundamental role in condensed matter physics, since many phenomena e.g. magnetic ordering, electrical (as well as heat) transport properties, ultrafast magnetization processes, and most importantly electron/spin dynamics can only be understood when these quasi-particles are taken into consideration. In addition to their fundamental importance, magnons may also be used for information processing in modern spintronics. Here the concept of spin excitations in ultrathin itinerant magnets is discussed and reviewed. Starting with a historical introduction, different classes of magnons are introduced. Different theoretical treatments of spin excitations in solids are outlined. Interaction of spin-polarized electrons with a magnetic surface is discussed. It is shown that, based on the quantum mechanical conservation rules, a magnon can only be excited when a minority electron is injected into the system. While the magnon creation process is forbidden by majority electrons, the magnon annihilation process is allowed instead. These fundamental quantum mechanical selection rules, together with the strong interaction of electrons with matter, make the spin-polarized electron spectroscopies as appropriate tools to excite and probe the elementary spin excitations in low-dimensional magnets e.g ultrathin films and nanostructures. The focus is put on the experimental results obtained by spin-polarized electron energy loss spectroscopy and spin-polarized inelastic tunneling spectroscopy. The magnon dispersion relation, lifetime, group and phase velocity measured using these approaches in various ultrathin magnets are discussed in detail. The differences and similarities with respect to the bulk excitations are addressed. The role of the temperature, atomic structure, number of atomic layers, lattice strain, electronic complexes and hybridization at the interfaces are outlined. A possibility of simultaneous probing of magnons and phonons
8. Charmonium non-potential excitations
International Nuclear Information System (INIS)
Borue, V.Y.; Khokhlachev, S.B.
1990-01-01
Within the framework of an effective theory of quantum gluodynamics formulated earlier in terms of the glueball degrees of freedom, the excitations of gluon bunch formed by heavy quark and antiquark are considered. It is shown that these excitations correspond to the vibration of the gluon bunch shape and lie nearly 800 MeV higher than the charmonium ground state. The consequences of the existence of these excitations are discussed
9. Response of HDR-VKL piping system to seismic test excitations: Comparison of analytical predictions and test measurements
International Nuclear Information System (INIS)
Srinivasan, M.G.; Kot, C.A.; Hsieh, B.J.
1989-01-01
As part of the earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) piping system. The purpose of these experiments was to study the behavior of piping subjected to a range of seismic excitation levels including those that exceed design levels manifold and that might induce failure of pipe supports or plasticity in the pipe runs, and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also used to validate analysis methods. Detailed reports on the SHAM experiments are given elsewhere. The objective of this document is to evaluate a subsystem analysis module of the SMACS code. This module is a linear finite-element based program capable of calculating the response of nuclear power plant subsystems subjected to independent multiple-acceleration input excitation. The evaluation is based on a comparison of computational results of simulation of SHAM tests with corresponding test measurements
10. Antiferromagnetic resonance excited by oscillating electric currents
Science.gov (United States)
Sluka, Volker
2017-12-01
In antiferromagnetic materials the order parameter exhibits resonant modes at frequencies that can be in the terahertz range, making them interesting components for spintronic devices. Here, it is shown that antiferromagnetic resonance can be excited using the inverse spin-Hall effect in a system consisting of an antiferromagnetic insulator coupled to a normal-metal waveguide. The time-dependent interplay between spin torque, ac spin accumulation, and magnetic degrees of freedom is studied. It is found that the dynamics of the antiferromagnet affects the frequency-dependent conductivity of the normal metal. Further, a comparison is made between spin-current-induced and Oersted-field-induced excitation under the condition of constant power injection.
11. Dissociative Excitation of Adenine by Electron Impact
Science.gov (United States)
McConkey, J. William; Trocchi, Joshuah; Dech, Jeffery; Kedzierski, Wladek
2017-04-01
Dissociative excitation of adenine (C6H5NH2) into excited atomic fragments has been studied in the electron impact energy range from threshold to 300 eV. A crossed beam system coupled to a vacuum ultraviolet (VUV) monochromator is used to study emissions in the wavelength range from 110 to 200 nm. The beam of adenine vapor from a stainless steel oven is crossed at right angles by the electron beam and the resultant UV radiation is detected in a mutually orthogonal direction. The strongest feature in the spectrum is H Lyman- α. Financial support from NSERC and CFI, Canada, is gratefully acknowledged.
12. Phased Array Excitations For Efficient Near Field Wireless Power Transmission
Science.gov (United States)
2016-09-01
channeled to the battery or power plant. Figure 2. WPT System Block Diagram for Battery Charging. Source : [2]. Wireless power transfer has gained...EXCITATIONS FOR EFFICIENT NEAR-FIELD WIRELESS POWER TRANSMISSION by Sean X. Hong September 2016 Thesis Advisor: David Jenn Second Reader...TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE PHASED ARRAY EXCITATIONS FOR EFFICIENT NEAR-FIELD WIRELESS POWER TRANSMISSION 5
13. Electromagnetic excitation of 136Xe in relativistic heavy ion collisions
International Nuclear Information System (INIS)
Schmidt, R.D.
1991-11-01
In the framework of the experimental program at the accelerator facilities SIS/ESR at the Society for Heavy Ion Research in Darmstadt a detector system for relativistic neutrons was developed, constructed, and applied in first experiments. An essential research aim is the study of collective states after electromagnetic excitation in relativistic heavy ion collisions. In peripheral collisions high-energy virtual photons are exchanged. This leads to the excitation of giant resonances, especially of the giant dipole and quadrupole resonance. An essential decay channel of giant resonances in heavy nuclei is the emission of neutrons, followed by the emission of γ radiation below the particle threshold. These decay channels were studied with the detector system developed by the LAND collaboration. A first experiment on the electromagnetic excitation was performed with a 136 Xe beam at an energy of 700 MeV/u and Pb respectively C targets. (orig./HSI) [de
14. Multi-quantum excitation in optically pumped alkali atom: rare gas mixtures
Science.gov (United States)
Galbally-Kinney, K. L.; Rawlins, W. T.; Davis, S. J.
2014-03-01
Diode-pumped alkali laser (DPAL) technology offers a means of achieving high-energy gas laser output through optical pumping of the D-lines of Cs, Rb, and K. The exciplex effect, based on weak attractive forces between alkali atoms and polarizable rare gas atoms (Ar, Kr, Xe), provides an alternative approach via broadband excitation of exciplex precursors (XPAL). In XPAL configurations, we have observed multi-quantum excitation within the alkali manifolds which result in infrared emission lines between 1 and 4 μm. The observed excited states include the 42FJ states of both Cs and Rb, which are well above the two-photon energy of the excitation laser in each case. We have observed fluorescence from multi-quantum states for excitation wavelengths throughout the exciplex absorption bands of Cs-Ar, Cs-Kr, and Cs-Xe. The intensity scaling is roughly first-order or less in both pump power and alkali concentration, suggesting a collisional energy pooling excitation mechanism. Collisional up-pumping appears to present a parasitic loss term for optically pumped atomic systems at high intensities, however there may also be excitation of other lasing transitions at infrared wavelengths.
15. Trapping time statistics and efficiency of transport of optical excitations in dendrimers
OpenAIRE
Heijs, D.J.; Malyshev, V.A.; Knoester, J.
2004-01-01
We theoretically study the trapping time distribution and the efficiency of the excitation energy transport in dendritic systems. Trapping of excitations, created at the periphery of the dendrimer, on a trap located at its core, is used as a probe of the efficiency of the energy transport across the dendrimer. The transport process is treated as incoherent hopping of excitations between nearest-neighbor dendrimer units and is described using a rate equation. We account for radiative and non-r...
16. The MSINDO-sCIS and MSINDO-UCIS methods. Procedures for the calculation of properties of excited states in molecules and periodic systems by a semiempirical approach
International Nuclear Information System (INIS)
2013-01-01
Theoretical background, parameterization and performance of the newly developed semiempirical configuration interaction singles (CIS) method MSINDO-sCIS (scaled configuration interaction singles) are presented. The CIS Hamiltonian is modified by scaling of the Coulomb and exchange integrals and a semiempirical correction of the diagonal elements. For a recently proposed benchmark set of 28 medium-sized organic molecules, vertical excitation energies for singlet and triplet states have been calculated and statistically evaluated. A full reparameterization of the MSINDO method for both ground and excited state properties was performed. The results of the reparameterized MSINDO-sCIS method are compared to the currently best semiempirical method for excited states, OM3-CISDTQ by Thiel et al., and to other standard methods, such as time-dependent density- functional theory. The mean absolute deviation with respect to the theoretical best estimates (TBEs) for MSINDO-sCIS is 0.44 eV, comparable to the OM3 method but significantly smaller than for Zerner's INDO/S. The computational effort is strongly reduced compared to OM3-CISDTQ and OM3-MRCISD, since only single excitations are taken into account. Higher excitations are implicitly included by parameterization and the empirical correction term. By application of the Davidson-Liu block diagonalization method high computational efficiency is achieved. Furthermore it is demonstrated, that the MSINDO-sCIS method correctly describes charge-transfer (CT) states, that represent a crucial problem for time-dependent density functional theory (TD-DFT) methods. Additionally this method is extended to open-shell systems by the UCIS (unrestricted CIS) approach. MSINDO allows the calculation of periodic systems via the cyclic cluster model (CCM) which is a direct-space approach and therefore can be in principle combined with all molecular quantum-chemical techniques. The sCIS/UCIS equations are solved for a cluster with periodic
17. Using narrowband excitation to confirm that the S∗ state in carotenoids is not a vibrationally-excited ground state species
Science.gov (United States)
Jailaubekov, Askat E.; Song, Sang-Hun; Vengris, Mikas; Cogdell, Richard J.; Larsen, Delmar S.
2010-02-01
The hypothesis that S∗ is a vibrationally-excited ground-state population is tested and discarded for two carotenoid samples: β-carotene in solution and rhodopin glucoside embedded in the light harvesting 2 protein from Rhodopseudomonas acidophila. By demonstrating that the transient absorption signals measured in both systems that are induced by broadband (1000 cm -1) and narrowband (50 cm -1) excitation pulses are near identical and hence bandwidth independent, the impulsive stimulated Raman scattering mechanism proposed as the primary source for S∗ generation is discarded. To support this conclusion, previously published multi-pulse pump-dump-probe signals [17] are revisited to discard secondary mechanisms for S∗ formation.
18. Connectivity, excitability and activity patterns in neuronal networks
International Nuclear Information System (INIS)
Le Feber, Joost; Stoyanova, Irina I; Chiappalone, Michela
2014-01-01
Extremely synchronized firing patterns such as those observed in brain diseases like epilepsy may result from excessive network excitability. Although network excitability is closely related to (excitatory) connectivity, a direct measure for network excitability remains unavailable. Several methods currently exist for estimating network connectivity, most of which are related to cross-correlation. An example is the conditional firing probability (CFP) analysis which calculates the pairwise probability (CFP i,j ) that electrode j records an action potential at time t = τ, given that electrode i recorded a spike at t = 0. However, electrode i often records multiple spikes within the analysis interval, and CFP values are biased by the on-going dynamic state of the network. Here we show that in a linear approximation this bias may be removed by deconvoluting CFP i,j with the autocorrelation of i (i.e. CFP i,i ), to obtain the single pulse response (SPR i,j )—the average response at electrode j to a single spike at electrode i. Thus, in a linear system SPRs would be independent of the dynamic network state. Nonlinear components of synaptic transmission, such as facilitation and short term depression, will however still affect SPRs. Therefore SPRs provide a clean measure of network excitability. We used carbachol and ghrelin to moderately activate cultured cortical networks to affect their dynamic state. Both neuromodulators transformed the bursting firing patterns of the isolated networks into more dispersed firing. We show that the influence of the dynamic state on SPRs is much smaller than the effect on CFPs, but not zero. The remaining difference reflects the alteration in network excitability. We conclude that SPRs are less contaminated by the dynamic network state and that mild excitation may decrease network excitability, possibly through short term synaptic depression. (papers)
19. Passive listening to preferred motor tempo modulates corticospinal excitability.
Science.gov (United States)
Michaelis, Kelly; Wiener, Martin; Thompson, James C
2014-01-01
Rhythms are an essential characteristic of our lives, and auditory-motor coupling affects a variety of behaviors. Previous research has shown that the neural regions associated with motor system processing are coupled to perceptual rhythmic and melodic processing such that the perception of rhythmic stimuli can entrain motor system responses. However, the degree to which individual preference modulates the motor system is unknown. Recent work has shown that passively listening to metrically strong rhythms increases corticospinal excitability, as indicated by transcranial magnetic stimulation (TMS). Furthermore, this effect is modulated by high-groove music, or music that inspires movement, while neuroimaging evidence suggests that premotor activity increases with tempos occurring within a preferred tempo (PT) category. PT refers to the rate of a hypothetical endogenous oscillator that may be indicated by spontaneous motor tempo (SMT) and preferred perceptual tempo (PPT) measurements. The present study investigated whether listening to a rhythm at an individual's PT preferentially modulates motor system excitability. SMT was obtained in human participants through a tapping task in which subjects were asked to tap a response key at their most comfortable rate. Subjects listened a 10-beat tone sequence at 11 log-spaced tempos and rated their preference for each (PPT). We found that SMT and PPT measurements were correlated, indicating that preferred and produced tempos occurred at a similar rate. Crucially, single-pulse TMS delivered to left M1 during PPT judgments revealed that corticospinal excitability, measured by motor-evoked potentials (MEPs), was modulated by tempos traveling closer to individual PT. However, the specific nature of this modulation differed across individuals, with some exhibiting an increase in excitability around PT and others exhibiting a decrease. These findings suggest that auditory-motor coupling induced by rhythms is preferentially
20. Stochastic stability of mechanical systems under renewal jump process parametric excitation
DEFF Research Database (Denmark)
Iwankiewicz, R.; Nielsen, Søren R.K.; Larsen, Jesper Winther
2005-01-01
independent, negative exponential distributed variables; hence, the arrival process may be termed as a generalized Erlang renewal process. The excitation process is governed by the stochastic equation driven by two independent Poisson processes, with different parameters. If the response in a single mode...
1. Photoionization study of doubly-excited helium at ultra-high resolution
Energy Technology Data Exchange (ETDEWEB)
Kaindl, G.; Schulz, K.; Domke, M. [Freie Universitaet Berlin (Germany)] [and others
1997-04-01
Ever since the pioneering work of Madden & Codling and Cooper, Fano & Prats on doubly-excited helium in the early sixties, this system may be considered as prototypical for the study of electron-electron correlations. More detailed insight into these states could be reached only much later, when improved theoretical calculations of the optically-excited {sup 1}P{sup 0} double-excitation states became available and sufficiently high energy resolution ({delta}E=4.0 meV) was achieved. This allowed a systematic investigation of the double-excitation resonances of He up to excitation energies close to the double-ionization threshold, I{sub infinity}=79.003 eV, which stimulated renewed theoretical interest into these correlated electron states. The authors report here on striking progress in energy resolution in this grazing-incidence photon-energy range of grating monochromators and its application to hitherto unobservable states of doubly-excited He. By monitoring an extremely narrow double-excitation resonance of He, with a theoretical lifetime width of less than or equal to 5 {mu}eV, a resolution of {delta}E=1.0 meV (FWHM) at 64.1 eV could be achieved. This ultra-high spectral resolution, combined with high photon flux, allowed the investigation of new Rydberg resonances below the N=3 ionization threshold, I{sub 3}, as well as a detailed comparison with ab-initio calculations.
2. Surface boiling - an obvious but like no other decay mode of highly excited atomic nuclei
International Nuclear Information System (INIS)
Toke, J.
2012-01-01
Essentials of a generalized compound nucleus model are introduced based on a concept of an open microcanonical ensemble which considers explicitly the role of the diffuse surface domain and of the thermal expansion of nuclear systems in the quest for maximum entropy. This obvious generalization offers a unique and universal thermodynamic framework for understanding the changes in the gross behavior of excited nuclear systems with increasing excitation energy and, specifically, the competition between different statistical decay modes, including classical evaporation and binary fission, but also the Coulomb fragmentation of excited systems into multiple fragments - the famed multifragmentation. Importantly, the formalism offers a natural explanation, in terms of boiling or spinodal vaporization, for the experimentally observed appearance of limiting excitation energy that can be thermalized by an exited nuclear system and the associated limiting temperature. It is shown that it is the thermal expansion that leads to volume boiling in an infinite matter and surface boiling in finite nuclei. The latter constitutes an important and universal, but hitherto unappreciated decay mode of highly excited nuclei, a mode here named surface spinodal vaporization. It is also shown that in iso-asymmetric systems, thermal expansion leads to what constitutes distillation - a decay mode here named distillative spinodal vaporization
3. 340nm UV LED excitation in time-resolved fluorescence system for europium-based immunoassays detection
Science.gov (United States)
Rodenko, Olga; Fodgaard, Henrik; Tidemand-Lichtenberg, Peter; Pedersen, Christian
2017-02-01
In immunoassay analyzers for in-vitro diagnostics, Xenon flash lamps have been widely used as excitation light sources. Recent advancements in UV LED technology and its advantages over the flash lamps such as smaller footprint, better wall-plug efficiency, narrow emission spectrum, and no significant afterglow, have made them attractive light sources for gated detection systems. In this paper, we report on the implementation of a 340 nm UV LED based time-resolved fluorescence system based on europium chelate as a fluorescent marker. The system performance was tested with the immunoassay based on the cardiac marker, TnI. The same signal-to-noise ratio as for the flash lamp based system was obtained, operating the LED below specified maximum current. The background counts of the system and its main contributors were measured and analyzed. The background of the system of the LED based unit was improved by 39% compared to that of the Xenon flash lamp based unit, due to the LEDs narrower emission spectrum and longer pulse width. Key parameters of the LED system are discussed to further optimize the signal-to-noise ratio and signal-to-background, and hence the sensitivity of the instrument.
4. Efficient primary and parametric resonance excitation of bistable resonators
KAUST Repository
Ramini, Abdallah
2016-09-12
We experimentally demonstrate an efficient approach to excite primary and parametric (up to the 4th) resonance of Microelectromechanical system MEMS arch resonators with large vibrational amplitudes. A single crystal silicon in-plane arch microbeam is fabricated such that it can be excited axially from one of its ends by a parallel-plate electrode. Its micro/nano scale vibrations are transduced using a high speed camera. Through the parallel-plate electrode, a time varying electrostatic force is applied, which is converted into a time varying axial force that modulates dynamically the stiffness of the arch resonator. Due to the initial curvature of the structure, not only parametric excitation is induced, but also primary resonance. Experimental investigation is conducted comparing the response of the arch near primary resonance using the axial excitation to that of a classical parallel-plate actuation where the arch itself forms an electrode. The results show that the axial excitation can be more efficient and requires less power for primary resonance excitation. Moreover, unlike the classical method where the structure is vulnerable to the dynamic pull-in instability, the axial excitation technique can provide large amplitude motion while protecting the structure from pull-in. In addition to primary resonance, parametrical resonances are demonstrated at twice, one-half, and two-thirds the primary resonance frequency. The ability to actuate primary and/or parametric resonances can serve various applications, such as for resonator based logic and memory devices. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license
5. Mean excitation energies for molecular ions
Energy Technology Data Exchange (ETDEWEB)
Jensen, Phillip W.K.; Sauer, Stephan P.A. [Department of Chemistry, University of Copenhagen, Copenhagen (Denmark); Oddershede, Jens [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States); Sabin, John R., E-mail: [email protected] [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Odense (Denmark); Quantum Theory Project, Departments of Physics and Chemistry, University of Florida, Gainesville, FL (United States)
2017-03-01
The essential material constant that determines the bulk of the stopping power of high energy projectiles, the mean excitation energy, is calculated for a range of smaller molecular ions using the RPA method. It is demonstrated that the mean excitation energy of both molecules and atoms increase with ionic charge. However, while the mean excitation energies of atoms also increase with atomic number, the opposite is the case for mean excitation energies for molecules and molecular ions. The origin of these effects is explained by considering the spectral representation of the excited state contributing to the mean excitation energy.
6. Strange effects of strong high-frequency excitation
DEFF Research Database (Denmark)
Thomsen, Jon Juel
2003-01-01
Three general effects of mechanical high-frequency excitation (HFE) are described: Stiffening - an apparent change in the stiffness associated with an equilibrium; Biasing - a tendency for a system to move towards a particular state which does not exist or is unstable without HFE; and Smoothening...
7. Perturbation Solutions for Random Linear Structural Systems subject to Random Excitation using Stochastic Differential Equations
DEFF Research Database (Denmark)
Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.
1994-01-01
perturbation method using stochastic differential equations. The joint statistical moments entering the perturbation solution are determined by considering an augmented dynamic system with state variables made up of the displacement and velocity vector and their first and second derivatives with respect......The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order...... to the random parameters of the problem. Equations for partial derivatives are obtained from the partial differentiation of the equations of motion. The zero time-lag joint statistical moment equations for the augmented state vector are derived from the Itô differential formula. General formulation is given...
8. Electro-mechanical impact system excited by a source of limited power
Czech Academy of Sciences Publication Activity Database
2008-01-01
Roč. 15, č. 6 (2008), s. 1-10 ISSN 1802-1484 R&D Projects: GA ČR GA101/06/0063 Institutional research plan: CEZ:AV0Z20760514 Keywords : mechanical oscillations * impacts * limited power of exciter * electro-mechanical interaction Subject RIV: BI - Acoustics
9. Excited fermions
International Nuclear Information System (INIS)
Boudjema, F.; Djouadi, A.; Kneur, J.L.
1992-01-01
The production of excited fermions with mass above 100 GeV is considered. f→Vf (1) decay widths are calculated where V=γ, Z or W. Excited fermion pair production in e + e - annihilation and in γγ collisions, and single production in e + e - annihilation, eγ and γγ collisions is also discussed. Cross sections are calculated for all these cases. The discovery potential of the NLC at 500 GeV is compared with that of other colliders. (K.A.) 15 refs., 5 figs., 2 tabs
10. Deviations from excitation equilibrium in optically thick mercury arc plasmas
International Nuclear Information System (INIS)
Karabourniotis, D.; Couris, S.; Damelincourt, J.J.
1989-01-01
Up to date mercury arcs at pressure greater than 1 atm have been investigated as plasma systems in local thermodynamic equilibrium (LTE) state. These studies have been motivated by the applications of mercury arcs, e.g., in the lighting industry. The LTE-assumption simplifies the use of spectroscopic diagnostics and the performance of species-concentration calculations. A high pressure mercury arc of about 1 atm had been considered in two possibilities: excitation and gas temperatures are the same, the electron temperature is higher and excitation and electron temperatures are the same, the gas temperature is lower. Recent measurements in mercury arcs reveal the existence of severe departures from thermal equilibrium and suggest the absence of excitation equilibrium in the axis and in the periphery in such an arc. The deviation from equilibrium leads to complicated distributions, such that the system cannot be described correctly by any single temperature. This becomes quite complicated when plasma inhomogeneity and strong reabsorption of the radiation are present
11. Development and Implementation of Biological Circuits Using Excitable and Non-Excitable Cells
Energy Technology Data Exchange (ETDEWEB)
Casasnovas-Orus, V.; Gomez-Cid, L.; Hernandez-Romero, I.; Fuentes, L.; Guillem, M.S.; Atienza, F.; Fernandez-Aviles, F.; Climent, A.M.
2016-07-01
Compared to conventional computation systems, living beings require reduced power and raw materials consumption, inviting to explore the concept of biological circuits. In this project, a proof-of-concept of logical biocircuits using cell patterns has been developed. These were based upon differential ionic communication between cells, being the cells types used excitable and non-excitable, modeled by cardiomyocytes and fibroblasts correspondingly. To begin, patterns for the basic logic computation blocks were designed, including the OR gate, AND gate and logic memory. The designs were evaluated with mathematical models and in vitro experiments. Results of mathematical modeling indicated that theoretical approval of the biocircuit function. Regarding in vitro biocircuit implementation, three different selective cell localization techniques proved useful for the pattern creation. Evaluation with optical mapping confirmed the operation of the OR gate and logic memory. More resolution in the cell placement strategy will be needed to observe the proper AND gate operation. Thus, fine-tuning of the implementation process will enable the construction of more complex biocircuits that will take on clinical applications relating to electric stimulation of tissues and programmed drug delivery. (Author)
12. Excitation of autoionizing states of helium by 100 keV proton impact: II. Excitation cross sections and mechanisms of excitation
Energy Technology Data Exchange (ETDEWEB)
Godunov, A.L. [Department of Physics, Tulane University, New Orleans, LA 70118-5698 (United States); Ivanov, P.B.; Schipakov, V.A. [Troitsk Institute of Innovation and Fusion Research Troitsk, Moscow region, 142092 (Russian Federation); Moretto-Capelle, P.; Bordenave-Montesquieu, D.; Bordenave-Montesquieu, A. [Laboratoire Collisions, Agregats, Reactivite, IRSAMC, UMR 5589, CNRS-Universite Paul Sabatier, 31062 Toulouse Cedex (France)
2000-03-14
Mechanisms of two-electron excitation of the (2s{sup 2}){sup 1} S, (2p{sup 2} ){sup 1} D and (2s2p){sup 1} P autoionizing states of helium are studied both experimentally and theoretically. It is shown that an explicit introduction of a kinematic factor, with a process-specific phase leads to a productive parametrization of experimental cross sections of ionization, allowing one to extract cross sections of excitation of autoionizing states. Using a new fitting procedure together with the proposed parametrization made it possible to obtain the excitation cross sections and magnetic sublevel population from electron spectra as well as, for the first time, to resolve the contribution of resonance and interference components to resonance profiles. Interference with direct ionization is shown to contribute significantly into resonance formation even for backward ejection angles. We demonstrate theoretically that the excitation cross sections thus extracted from experimental electron spectra hold information about the interaction of autoionizing states with an adjacent continuum. (author)
13. Depolarization of a photoelectret under depth-nonuniform excitation of the sample
International Nuclear Information System (INIS)
Vavrek, A.F.; Khristova, K.K.
1988-01-01
A simple theoretical model is given and explaination is made of the experimental observations of the recently carried out destroying the photoelectret state (PES) in Bi 1 2SiO 2 0 (BSO) by X-ray irradiation. It is assumed that during the irradiatoin two regions are formed divided by a sharp boundary - an excited region I with mobile non-equilibrium carriers and non-excited region II without mobile carriers. According to the experimental conditions, the isolating layers are between the sample and the electrodes, the total photoelectret charge is zero and the PE charge before the irradiation have a barrier distribution. For the determination of a PE charge the method of photodepolarization is used. When the photoelectret is irradiated in region I, mobile carriers are generated which move under the influence of the electrical field in this region and begin to accumulate on the boundary plane between the excited and non-excited regions, thus forming a 'shifted' charge layer. There is no movement of charges in region II. The distribution of the charges and the electric field in such a multilayer system is described by a system of equations. It is established that during the X-ray irradiation the PE charge gradually decreases. However, the maximum charge which can be destroyed is found to be a function of the thickness of the excited region and becomes equal to the initial charge when an excitation of the whole sample takes place. The consideration done explains the experimentally observed seeming loss of sensitivity of the BSO to the X radiation
14. A ballistic transport model for electronic excitation following particle impact
Science.gov (United States)
Hanke, S.; Heuser, C.; Weidtmann, B.; Wucher, A.
2018-01-01
We present a ballistic model for the transport of electronic excitation energy induced by keV particle bombardment onto a solid surface. Starting from a free electron gas model, the Boltzmann transport equation (BTE) is employed to follow the evolution of the temporal and spatial distribution function f (r → , k → , t) describing the occupation probability of an electronic state k → at position r → and time t. Three different initializations of the distribution function are considered: i) a thermal distribution function with a locally and temporally elevated electron temperature, ii) a peak excitation at a specific energy above the Fermi level with a quasi-isotropic distribution in k-space and iii) an anisotropic peak excitation with k-vectors oriented in a specific transport direction. While the first initialization resembles a distribution function which may, for instance, result from electronic friction of moving atoms within an ion induced collision cascade, the peak excitation can in principle result from an autoionization process after excitation in close binary collisions. By numerically solving the BTE, we study the electronic energy exchange along a one dimensional transport direction to obtain a time and space resolved excitation energy distribution function, which is then analyzed in view of general transport characteristics of the chosen model system.
15. Collective excitations of harmonically trapped ideal gases
NARCIS (Netherlands)
Van Schaeybroeck, B.; Lazarides, A.
2009-01-01
We theoretically study the collective excitations of an ideal gas confined in an isotropic harmonic trap. We give an exact solution to the Boltzmann-Vlasov equation; as expected for a single-component system, the associated mode frequencies are integer multiples of the trapping frequency. We show
16. The Mean Excitation Energy of Atomic Ions
DEFF Research Database (Denmark)
Sauer, Stephan; Oddershede, Jens; Sabin, John R.
2015-01-01
A method for calculation of the mean excitation energies of atomic ions is presented, making the calculation of the energy deposition of fast ions to plasmas, warm, dense matter, and complex biological systems possible. Results are reported to all ions of helium, lithium, carbon, neon, aluminum...
17. Lie algebraic approach to valence bond theory of π-electron systems: a preliminary study of excited states
Science.gov (United States)
Paldus, J.; Li, X.
1992-10-01
Following a brief outline of various developments and exploitations of the unitary group approach (UGA), and its extension referred to as Clifford algebra UGA (CAUGA), in molecular electronic structure calculations, we present a summary of a recently introduced implementation of CAUGA for the valence bond (VB) method based on the Pariser-Parr-Pople (PPP)-type Hamiltonian. The existing applications of this PPP-VB approach have been limited to groundstates of various π-electron systems or, at any rate, to the lowest states of a given multiplicity. In this paper the method is applied to the low-lying excited states of several archetypal models, namely cyclobutadiene and benzene, representing antiaromatic and aromatic systems, hexatriene, representing linear polyenic systems and, finally, naphthalene, representing polyacenes.
18. Subsurface excitations in a metal
DEFF Research Database (Denmark)
Ray, M. P.; Lake, R. E.; Sosolik, C. E.
2009-01-01
We investigate internal hot carrier excitations in a Au thin film bombarded by hyperthermal and low energy alkali and noble gas ions. Excitations within the thin film of a metal-oxide-semiconductor device are measured revealing that ions whose velocities fall below the classical threshold given...... by the free-electron model of a metal still excite hot carriers. Excellent agreement between these results and a nonadiabatic model that accounts for the time-varying ion-surface interaction indicates that the measured excitations are due to semilocalized electrons near the metal surface....
19. Excited-state density functional theory
International Nuclear Information System (INIS)
Harbola, Manoj K; Hemanadhan, M; Shamim, Md; Samal, P
2012-01-01
Starting with a brief introduction to excited-state density functional theory, we present our method of constructing modified local density approximated (MLDA) energy functionals for the excited states. We show that these functionals give accurate results for kinetic energy and exchange energy compared to the ground state LDA functionals. Further, with the inclusion of GGA correction, highly accurate total energies for excited states are obtained. We conclude with a brief discussion on the further direction of research that include the construction of correlation energy functional and exchange potential for excited states.
20. Theory of singlet-doublet excitations in praseodymium
International Nuclear Information System (INIS)
Bak, P.
1975-10-01
The magnetic excitation spectrum in a paramagnetic singlet-doublet system is calculated using a diagrammatic high density expansion technique. The lowest order diagrams, which correspond to the random phase approximation (RPA), give a detailed description of the wave vector and temperature dependence of the four exciton modes in praseodymium in terms of a Hamiltonian including isotropic Heisenberg exchange interactions and anisotropic, dipolar-like interactions. The leading contributions to the linewidths of the excitations are obtained by extending the 1/Z expansion of the generalized susceptibility propagators one order beyond the random phase approximation. This damping corresponds to spin wave scattering on single-site fluctuations. The theoretical spectral functions are in detailed agreement with experiment
1. Excitable particles in an optical torque wrench
Science.gov (United States)
Pedaci, Francesco; Huang, Zhuangxiong; van Oene, Maarten; Barland, Stephane; Dekker, Nynke H.
2011-03-01
The optical torque wrench is a laser trapping technique capable of applying and directly measuring torque on microscopic birefringent particles using spin momentum transfer, and has found application in the measurement of static torsional properties of biological molecules such as single DNAs. Motivated by the potential of the optical torque wrench to access the fast rotational dynamics of biological systems, a result of its all-optical manipulation and detection, we focus on the angular dynamics of the trapped birefringent particle, demonstrating its excitability in the vicinity of a critical point. This links the optical torque wrench to nonlinear dynamical systems such as neuronal and cardiovascular tissues, nonlinear optics and chemical reactions, all of which display an excitable binary (`all-or-none') response to input perturbations. On the basis of this dynamical feature, we devise and implement a conceptually new sensing technique capable of detecting single perturbation events with high signal-to-noise ratio and continuously adjustable sensitivity.
2. Disorder-induced localization of excitability in an array of coupled lasers
Science.gov (United States)
Lamperti, M.; Perego, A. M.
2017-10-01
We report on the localization of excitability induced by disorder in an array of coupled semiconductor lasers with a saturable absorber. Through numerical simulations we show that the exponential localization of excitable waves occurs if a certain critical amount of randomness is present in the coupling coefficients among the lasers. The results presented in this Rapid Communication demonstrate that disorder can induce localization in lattices of excitable nonlinear oscillators, and can be of interest in the study of photonics-based random networks, neuromorphic systems, and, by analogy, in biology, in particular, in the investigation of the collective dynamics of neuronal cell populations.
3. The method of varying amplitudes for solving (non)linear problems involving strong parametric excitation
DEFF Research Database (Denmark)
2015-01-01
Parametrically excited systems appear in many fields of science and technology, intrinsically or imposed purposefully; e.g. spatially periodic structures represent an important class of such systems [4]. When the parametric excitation can be considered weak, classical asymptotic methods like...... the method of averaging [2] or multiple scales [6] can be applied. However, with many practically important applications this simplification is inadequate, e.g. with spatially periodic structures it restricts the possibility to affect their effective dynamic properties by a structural parameter modulation...... of considerable magnitude. Approximate methods based on Floquet theory [4] for analyzing problems involving parametric excitation, e.g. the classical Hill’s method of infinite determinants [3,4], can be employed also in cases of strong excitation; however, with Floquet theory being applicable only for linear...
4. Optimal Excitation Controller Design for Wind Turbine Generator
Directory of Open Access Journals (Sweden)
A. K. Boglou
2011-01-01
Full Text Available An optimal excitation controller design based on multirate-output controllers (MROCs having a multirate sampling mechanismwith different sampling period in each measured output of the system is presented. The proposed H∞ -control techniqueis applied to the discrete linear open-loop system model which represents a wind turbine generator supplying an infinite busthrough a transmission line.
5. Multi-frequency exciting and spectrogram-based ECT method
CERN Document Server
2000-01-01
The purpose of this paper is to experimentally demonstrate advantages of a multi-frequency ECT system. In this system, a precise crack imaging was achieved by using spectrograms obtained from an eddy-current probe multi-frequency response. A complex signal containing selected sinusoidal components was used as an excitation. The results of measurements for various test specimens are presented.
6. Does intrinsic motivation enhance motor cortex excitability?
Science.gov (United States)
Radel, Rémi; Pjevac, Dusan; Davranche, Karen; d'Arripe-Longueville, Fabienne; Colson, Serge S; Lapole, Thomas; Gruet, Mathieu
2016-11-01
Intrinsic motivation (IM) is often viewed as a spontaneous tendency for action. Recent behavioral and neuroimaging evidence indicate that IM, in comparison to extrinsic motivation (EM), solicits the motor system. Accordingly, we tested whether IM leads to greater excitability of the motor cortex than EM. To test this hypothesis, we used two different tasks to induce the motivational orientation using either words representing each motivational orientation or pictures previously linked to each motivational orientation through associative learning. Single-pulse transcranial magnetic stimulation over the motor cortex was applied when viewing the stimuli. Electromyographic activity was recorded on the contracted first dorsal interosseous muscle. Two indexes of corticospinal excitability (the amplitude of motor-evoked potential and the length of cortical silent period) were obtained through unbiased automatic detection and analyzed using a mixed model that provided both statistical power and a high level of control over all important individual, task, and stimuli characteristics. Across the two tasks and the two indices of corticospinal excitability, the exposure to IM-related stimuli did not lead to a greater corticospinal excitability than EM-related stimuli or than stimuli with no motivational valence (ps > .20). While these results tend to dismiss the advantage of IM at activating the motor cortex, we suggest alternative hypotheses to explain this lack of effect, which deserves further research. © 2016 Society for Psychophysiological Research.
7. Breakup excitation function at backward angles from α-spectra in the 6Li + 144Sm system
International Nuclear Information System (INIS)
Capurro, O.A.; Pacheco, A.J.; Arazi, A.; Figueira, J.M.; Martinez Heimann, D.; Negri, A.E.
2011-01-01
Breakup cross sections were obtained for the 6 Li + 144 Sm system at energies above and below the Coulomb barrier from a detailed analysis of the data recorded at backward angles. These cross sections are compared with inelastic target excitations previously reported revealing a similar behavior as a function of the bombarding energy but a large absolute difference between them. Using kinematical considerations we have analyzed possible contributions from different breakup channels and we have extracted information on magnitudes such as the relative kinetic energies of the corresponding breakup fragments.
8. Excitation and decay of correlated atomic states
International Nuclear Information System (INIS)
Rau, A.R.P.
1992-01-01
Doubly excited states of atoms and ions in which two electrons are excited from the ground configuration display strong radial and angular electron correlations. They are prototypical examples of quantum-mechanical systems with strong coupling. Two distinguishing characteristics of these states are: (1) their organization into successive families, with only weak coupling between families, and (2) a hierarchical nature of this coupling, with states from one family decaying primarily to those in the next lower family. A view of the pair of electrons as a single entity, with the electron-electron repulsion between them divided into a adiabatic and nonadiabatic piece, accounts for many of the dominant features. The stronger, adiabatic part determines the family structure and the weaker, nonadiabatic part the excitation and decay between successive families. Similar considerations extend to three-electron atomic states, which group into five different classes. They are suggestive of composite models for quarks in elementary particle physics, which exhibit analogous groupings into families with a hierarchical arrangement of masses and electroweak decays. 49 refs., 6 figs., 2 tabs
9. Fermionic Collective Excitations in a Lattice Gas of Rydberg Atoms
International Nuclear Information System (INIS)
Olmos, B.; Gonzalez-Ferez, R.; Lesanovsky, I.
2009-01-01
We investigate the many-body quantum states of a laser-driven gas of Rydberg atoms confined to a large spacing ring lattice. If the laser driving is much stronger than the van der Waals interaction among the Rydberg atoms, these many-body states are collective fermionic excitations. The first excited state is a spin wave that extends over the entire lattice. We demonstrate that our system permits us to study fermions in the presence of disorder although no external atomic motion takes place. We analyze how this disorder influences the excitation properties of the fermionic states. Our work shows a route towards the creation of complex many-particle states with atoms in lattices.
10. Dynamical analysis of highly excited molecular spectra
Energy Technology Data Exchange (ETDEWEB)
Kellman, M.E. [Univ. of Oregon, Eugene (United States)
1993-12-01
The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.
11. Deexcitation of single excited nuclei in the QMD model
International Nuclear Information System (INIS)
Mueller, W.; Begemann-Blaich, M.; Aichelin, J.
1992-10-01
We investigate the emission pattern of a single excited nucleus in the QMD model and compare the results with several statistical and phenomenological models. We find that the number of intermediate mass fragments as a function of the excitation energy is in very good agreement with the results of statistical models in which the emission pattern is governed by phase space only. This allows two conclusions: (a) The microscopic dynamical description of the disintegration of static excited nuclei in the QMD yields directly the emission pattern expected from phase space decay. This is the case despite of the fact that nuclear level densities are not given directly but are modeled semiclassically by the nucleon-nucleon interaction. Thus there is no need to supplement the QMD calculations by an additional evaporation model. (b) Differences between the QMD results and the data are not due to insufficiencies in the description of the disintegration of excited systems. Thus other possible reasons, like a substantial change of the free cross section in the nuclear environment have to be investigated. (orig.)
12. Field-dependent molecular ionization and excitation energies: Implications for electrically insulating liquids
Directory of Open Access Journals (Sweden)
N. Davari
2014-03-01
Full Text Available The molecular ionization potential has a relatively strong electric-field dependence as compared to the excitation energies which has implications for electrical insulation since the excited states work as an energy sink emitting light in the UV/VIS region. At some threshold field, all the excited states of the molecule have vanished and the molecule is a two-state system with the ground state and the ionized state, which has been hypothesized as a possible origin of different streamer propagation modes. Constrained density-functional theory is used to calculate the field-dependent ionization potential of different types of molecules relevant for electrically insulating liquids. The low singlet-singlet excitation energies of each molecule have also been calculated using time-dependent density functional theory. It is shown that low-energy singlet-singlet excitation of the type n → π* (lone pair to unoccupied π* orbital has the ability to survive at higher fields. This type of excitation can for example be found in esters, diketones and many color dyes. For alkanes (as for example n-tridecane and cyclohexane on the other hand, all the excited states, in particular the σ → σ* excitations vanish in electric fields higher than 10 MV/cm. Further implications for the design of electrically insulating dielectric liquids based on the molecular ionization potential and excitation energies are discussed.
13. Hydrological excitation of polar motion by different variables from the GLDAS models
Science.gov (United States)
Winska, Malgorzata; Nastula, Jolanta; Salstein, David
2017-12-01
Continental hydrological loading by land water, snow and ice is a process that is important for the full understanding of the excitation of polar motion. In this study, we compute different estimations of hydrological excitation functions of polar motion (as hydrological angular momentum, HAM) using various variables from the Global Land Data Assimilation System (GLDAS) models of the land-based hydrosphere. The main aim of this study is to show the influence of variables from different hydrological processes including evapotranspiration, runoff, snowmelt and soil moisture, on polar motion excitations at annual and short-term timescales. Hydrological excitation functions of polar motion are determined using selected variables of these GLDAS realizations. Furthermore, we use time-variable gravity field solutions from the Gravity Recovery and Climate Experiment (GRACE) to determine the hydrological mass effects on polar motion excitation. We first conduct an intercomparison of the maps of variations of regional hydrological excitation functions, timing and phase diagrams of different regional and global HAMs. Next, we estimate the hydrological signal in geodetically observed polar motion excitation as a residual by subtracting the contributions of atmospheric angular momentum and oceanic angular momentum. Finally, the hydrological excitations are compared with those hydrological signals determined from residuals of the observed polar motion excitation series. The results will help us understand the relative importance of polar motion excitation within the individual hydrological processes, based on hydrological modeling. This method will allow us to estimate how well the polar motion excitation budget in the seasonal and inter-annual spectral ranges can be closed.
14. Rydberg energies using excited state density functional theory
International Nuclear Information System (INIS)
Cheng, C.-L.; Wu Qin; Van Voorhis, Troy
2008-01-01
We utilize excited state density functional theory (eDFT) to study Rydberg states in atoms. We show both analytically and numerically that semilocal functionals can give quite reasonable Rydberg energies from eDFT, even in cases where time dependent density functional theory (TDDFT) fails catastrophically. We trace these findings to the fact that in eDFT the Kohn-Sham potential for each state is computed using the appropriate excited state density. Unlike the ground state potential, which typically falls off exponentially, the sequence of excited state potentials has a component that falls off polynomially with distance, leading to a Rydberg-type series. We also address the rigorous basis of eDFT for these systems. Perdew and Levy have shown using the constrained search formalism that every stationary density corresponds, in principle, to an exact stationary state of the full many-body Hamiltonian. In the present context, this means that the excited state DFT solutions are rigorous as long as they deliver the minimum noninteracting kinetic energy for the given density. We use optimized effective potential techniques to show that, in some cases, the eDFT Rydberg solutions appear to deliver the minimum kinetic energy because the associated density is not pure state v-representable. We thus find that eDFT plays a complementary role to constrained DFT: The former works only if the excited state density is not the ground state of some potential while the latter applies only when the density is a ground state density.
15. Experimental system to measure excitation cross-sections by electron impact. Measurements for ArI and ArII
International Nuclear Information System (INIS)
Blanco, F.; Sanchez, J.A.; Aguilera, J.A.; Campos, J.
1989-01-01
An experimental set-up to measure excitation cross-section of atomic and molecular levels by electron impact based on the optical method is reported. We also present some measurements on the excitation cross-section for ArI 5p'(1/2)0 level, and for simultaneous ionization and excitation of Ar leading to ArII levels belonging to the 3p 4 4p and 3p 4 4d configurations. (Author)
16. Nonlinear Response of Vibrational Conveyers with Nonideal Vibration Exciter: Superharmonic and Subharmonic Resonance
Directory of Open Access Journals (Sweden)
H. Bayıroğlu
2012-01-01
Full Text Available Vibrational conveyers with a centrifugal vibration exciter transmit their load based on the jumping method. Common unbalanced-mass driver oscillates the trough. The motion is strictly related to the vibrational parameters. The transition over resonance of a vibratory system, excited by rotating unbalances, is important in terms of the maximum vibrational amplitude produced and the power demand on the drive for the crossover. The mechanical system is driven by the DC motor. In this study, the working ranges of oscillating shaking conveyers with nonideal vibration exciter have been analyzed analytically for superharmonic and subharmonic resonances by the method of multiple scales and numerically. The analytical results obtained in this study agree well with the numerical results.
17. Excited waves in shear layers
Science.gov (United States)
Bechert, D. W.
1982-01-01
The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.
18. Non-linear quenching of current fluctuations in a self-exciting homopolar dynamo, proved by feedback system theory
Science.gov (United States)
de Paor, A. M.
Hide (Nonlinear Processes in Geophysics, 1998) has produced a new mathematical model of a self-exciting homopolar dynamo driving a series- wound motor, as a continuing contribution to the theory of the geomagnetic field. By a process of exact perturbation analysis, followed by combination and partial solution of differential equations, the complete nonlinear quenching of current fluctuations reported by Hide in the case that a parameter ɛ has the value 1 is proved via the Popov theorem from feedback system stability theory.
19. Efficient excitation of nonlinear phonons via chirped pulses: Induced structural phase transitions
Science.gov (United States)
Itin, A. P.; Katsnelson, M. I.
2018-05-01
Nonlinear phononics play important role in strong laser-solid interactions. We discuss a dynamical protocol for efficient phonon excitation, considering recent inspiring proposals: inducing ferroelectricity in paraelectric perovskites, and inducing structural deformations in cuprates [Subedi et al., Phys. Rev. B 89, 220301(R) (2014), 10.1103/PhysRevB.89.220301; Phys. Rev. B 95, 134113 (2017), 10.1103/PhysRevB.95.134113]. High-frequency phonon modes are driven by midinfrared pulses, and coupled to lower-frequency modes those indirect excitations cause structural deformations. We study in more detail the case of KTaO3 without strain, where it was not possible to excite the needed low-frequency phonon mode by resonant driving of the higher frequency one. Behavior of the system is explained using a reduced model of coupled driven nonlinear oscillators. We find a dynamical mechanism which prevents effective excitation at resonance driving. To induce ferroelectricity, we employ driving with sweeping frequency, realizing so-called capture into resonance. The method can be applied to many other related systems.
20. Effects of dynamic aspects on fusion excitation functions
International Nuclear Information System (INIS)
Hassan, G.S.
2008-01-01
As an extension of the macroscopic theory, the nucleus- nucleus fusion has been described in terms of the chaotic regime dynamics (liquid drop potential energy plus one body dissipation).Three milestone configurations are attended : the touching , the conditional saddle point and the unconditional saddle one. We would like to deduce the associated extra push and extra-extra push energy values required to carry the system between these configurations, respectively. The next step is to light on the effect of these limiting values on the fusion excitation functions and their significance for accurate fitting of the measured functions for larger values of the angular momentum. It is found that there is a limiting values of excitation energy and angular momentum for each interacting pair, over which these aspects must be considered to fit the excitation functions of different nucleus nucleus fusion .These values were found to be in relation with the limiting angular momentum for fusion in major cases
1. EPR studies of excited state exchange and crystal-field effects in rare earth compounds
International Nuclear Information System (INIS)
Huang, C.Y.; Sugawara, K.; Cooper, B.R.
1976-01-01
EPR in excited crystal-field states of Tm 3+ , Pr 3+ , and Tb 3+ in singlet-ground-state systems and in the excited state of Ce 3+ in CeP are reviewed. Because one is looking at a crystal-field excited state resonance, the exchange, even if isotropic, does not act as a secular perturbation. This means that one obtains different effects and has access to more information about the dynamic effects of exchange than in conventional paramagnetic resonance experiments. The Tm and Pr monopnictides studied are paramagnetic at all temperatures. The most striking feature of the behavior of the GAMMA 5 /sup (2)/ EPR in the Tm compounds is the presence of an anomalous maximum in the temperature dependence of the g-factor. The relationship of this effect to anisotropic exchange is discussed. The results of the EPR of the excited GAMMA 5 /sup (2)/ level of Tb 3 + (g-factor becomes very large at T/sub N/ in antiferromagnetic TbX (X = P, As, Sb) and that of the excited GAMMA 8 level of Ce 3+ in antiferromagnetic CeP will also be reported. For sufficient dilution of the Tb 3+ in the terbium monopnictides, the systems become paramagnetic (Van Vleck paramagnets) down to 0 0 K. The Tb 3+ excited state resonance EPR in Tb/sub 0.1/ La/sub 0.9/P was studied as an example of behavior in such systems. 10 fig
2. Power Management of Islanded Self-Excited Induction Generator Reinforced by Energy Storage Systems
Directory of Open Access Journals (Sweden)
Nachat N. Nasser
2018-02-01
Full Text Available Self-Excited Induction Generators (SEIGs, e.g., Small-Scale Embedded wind generation, are increasingly used in electricity distribution networks. The operational stability of stand-alone SEIG is constrained by the local load conditions: stability can be achieved by maintaining the load’s active and reactive power at optimal values. Changes in power demand are dependent on customers’ requirements, and any deviation from the pre-calculated optimum setting will affect a machine’s operating voltage and frequency. This paper presents an investigation of the operation of the SEIG in islanding mode of operation under different load conditions, with the aid of batteries as an energy storage source. In this research a current-controlled voltage-source converter is proposed to regulate the power exchange between a direct current (DC energy storage source and an alternating current (AC grid, the converter’s controller is driven by any variation between machine capability and load demand. In order to prolong the system stability when the battery reaches its operation constraints, it is recommended that an ancillary generator and a dummy local load be embedded in the system. The results show the robustness and operability of the proposed system in the islanding mode of the SEIG under different load conditions.
3. Proving test on the performance of a Multiple-Excitation Simulator
International Nuclear Information System (INIS)
Fujita, Katsuhisa; Ito, Tomohiro; Kojima, Nobuyuki; Sasaki, Yoichi; Abe, Hiroshi; Kuroda, Katsuhiko
1995-01-01
Seismic excitation test on large scale piping systems is scheduled to be carried out by the Nuclear power Engineering Corporation (NUPEC) using the large-scale, high-performance vibration table at the Tadotsu Engineering Laboratory, under the sponsorship of the Ministry of International Trade and Industry (MITI). In the test, the piping systems simulate the main steam piping system and the main feed water piping system in the nuclear power plants. In this study, a fundamental test was carried out to prove the performance of the Multiple Excitation Simulator which consists of the hydraulic actuator and the control system. An L-shaped piping system and a hydraulic actuator were installed on the shaking table. Acceleration and displacement generated by the actuator were measured. The performance of the actuator and the control system was discussed comparing the measured values and the target values on the time histories and the response spectrum of the acceleration. As a result, it was proved that the actuator and the control system have good performance and will be applicable to the verification test
4. Interfacial Phenomena of Magnetic Fluid with Permanent Magnet in a Longitudinally Excited Container
International Nuclear Information System (INIS)
Sudo, Seiichi; Wakuda, Hirofumi; Yano, Tetsuya
2008-01-01
This paper describes the magnetic fluid sloshing in a longitudinally excited container. Liquid responses of magnetic fluid with a permanent magnet in a circular cylindrical container subject to vertical vibration are investigated. Experiments are performed on a vibration- testing system which provided longitudinal excitation. A cylindrical container made with the acrylic plastic is used in the experiment. A permanent magnet is in the state of floating in a magnetic fluid. The disk-shaped and ring-shaped magnets are examined. The different interfacial phenomena from the usual longitudinal liquid sloshing are observed. It is found that the wave motion frequency of magnetic fluid with a disk-shaped magnet in the container subject to vertical vibration is exactly same that of the excitation. In the case of ring-shaped magnet, the first symmetrical mode of one-half subharmonic response is dominant at lower excitation frequencies. The magnetic fluid disintegration of the free surface was also observed by a high-speed video camera system
5. Interfacial Phenomena of Magnetic Fluid with Permanent Magnet in a Longitudinally Excited Container
Science.gov (United States)
Sudo, Seiichi; Wakuda, Hirofumi; Yano, Tetsuya
2008-02-01
This paper describes the magnetic fluid sloshing in a longitudinally excited container. Liquid responses of magnetic fluid with a permanent magnet in a circular cylindrical container subject to vertical vibration are investigated. Experiments are performed on a vibration- testing system which provided longitudinal excitation. A cylindrical container made with the acrylic plastic is used in the experiment. A permanent magnet is in the state of floating in a magnetic fluid. The disk-shaped and ring-shaped magnets are examined. The different interfacial phenomena from the usual longitudinal liquid sloshing are observed. It is found that the wave motion frequency of magnetic fluid with a disk-shaped magnet in the container subject to vertical vibration is exactly same that of the excitation. In the case of ring-shaped magnet, the first symmetrical mode of one-half subharmonic response is dominant at lower excitation frequencies. The magnetic fluid disintegration of the free surface was also observed by a high-speed video camera system.
6. Feasibility for detection of autofluorescent signatures in rat organs using a novel excitation-scanning hyperspectral imaging system
Science.gov (United States)
Favreau, Peter F.; Deal, Joshua A.; Weber, David S.; Rich, Thomas C.; Leavesley, Silas J.
2016-04-01
The natural fluorescence (autofluorescence) of tissues has been noted as a biomarker for cancer for several decades. Autofluorescence contrast between tumors and healthy tissues has been of significant interest in endoscopy, leading to development of autofluorescence endoscopes capable of visualizing 2-3 fluorescence emission wavelengths to achieve maximal contrast. However, tumor detection with autofluorescence endoscopes is hindered by low fluorescence signal and limited quantitative information, resulting in prolonged endoscopic procedures, prohibitive acquisition times, and reduced specificity of detection. Our lab has designed a novel excitation-scanning hyperspectral imaging system with high fluorescence signal detection, low acquisition time, and enhanced spectral discrimination. In this study, we surveyed a comprehensive set of excised tissues to assess the feasibility of detecting tissue-specific pathologies using excitation-scanning. Fresh, untreated tissue specimens were imaged from 360 to 550 nm on an inverted fluorescence microscope equipped with a set of thin-film tunable filters (Semrock, A Unit of IDEX). Images were subdivided into training and test sets. Automated endmember extraction (ENVI 5.1, Exelis) with PCA identified endmembers within training images of autofluorescence. A spectral library was created from 9 endmembers. The library was used for identification of endmembers in test images. Our results suggest (1) spectral differentiation of multiple tissue types is possible using excitation scanning; (2) shared spectra between tissue types; and (3) the ability to identify unique morphological features in disparate tissues from shared autofluorescent components. Future work will focus on isolating specific molecular signatures present in tissue spectra, and elucidating the contribution of these signatures in pathologies.
7. Development of 70 MW class superconducting generator with quick-response excitation
Science.gov (United States)
Miyaike, Kiyoshi; Kitajima, Toshio; Ito, Tetsuo
2002-03-01
The development of a superconducting generator had been carried out for 12 years under the first stage of a Super GM project. The 70 MW class model machine with quick response excitation was manufactured and evaluated in the project. This type of superconducting generator improves power system stability against rapid load fluctuations at the power system faults. This model machine achieved all development targets including high stability during rapid excitation control. It was also connected to the actual 77 kV electrical power grid as a synchronous condenser and proved advantages and high-operation reliability of the superconducting generator.
8. Nonlinear dynamic analysis of cantilevered piezoelectric energy harvesters under simultaneous parametric and external excitations
Science.gov (United States)
Fang, Fei; Xia, Guanghui; Wang, Jianguo
2018-02-01
The nonlinear dynamics of cantilevered piezoelectric beams is investigated under simultaneous parametric and external excitations. The beam is composed of a substrate and two piezoelectric layers and assumed as an Euler-Bernoulli model with inextensible deformation. A nonlinear distributed parameter model of cantilevered piezoelectric energy harvesters is proposed using the generalized Hamilton's principle. The proposed model includes geometric and inertia nonlinearity, but neglects the material nonlinearity. Using the Galerkin decomposition method and harmonic balance method, analytical expressions of the frequency-response curves are presented when the first bending mode of the beam plays a dominant role. Using these expressions, we investigate the effects of the damping, load resistance, electromechanical coupling, and excitation amplitude on the frequency-response curves. We also study the difference between the nonlinear lumped-parameter and distributed-parameter model for predicting the performance of the energy harvesting system. Only in the case of parametric excitation, we demonstrate that the energy harvesting system has an initiation excitation threshold below which no energy can be harvested. We also illustrate that the damping and load resistance affect the initiation excitation threshold.
9. 46 CFR 111.12-3 - Excitation.
Science.gov (United States)
2010-10-01
... 46 CFR 110.10-1). In particular, no static exciter may be used for excitation of an emergency generator unless it is provided with a permanent magnet or a residual-magnetism-type exciter that has the...
10. Plasmon assisted control of photo-induced excitation energy transfer in a molecular chain
Science.gov (United States)
Wang, Luxia; May, Volkhard
2017-08-01
The strong and ultrafast laser pulse excitation of a molecular chain in close vicinity to a spherical metal nano-particle (MNP) is studied theoretically. Due to local-field enhancement around the MNP, pronounced excited-state formation has to be expected for the part of the chain which is in proximity to the MNP. Here, the description of this phenomenon will be based on a uniform quantum theory of the MNP-molecule system. It accounts for local-field effects due to direct consideration of the strong excitation energy transfer coupling between the MNP and the various molecules. The molecule-MNP distances are chosen in such a way as to achieve a correct description of the MNP via dipole-plasmon excitations. Short plasmon life-times are incorporated in the framework of a density matrix approach. By extending earlier work the present description allows for multi-exciton formation and multiple dipole-plasmon excitation. The region of less intense and not-too-short optical excitation is identified as being best suited for excitation energy localization in the chain.
11. Excited states rotational effects on the behavior of excited molecules
CERN Document Server
Lim, Edward C
2013-01-01
Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also
12. Non-linear quenching of current fluctuations in a self-exciting homopolar dynamo, proved by feedback system theory
Directory of Open Access Journals (Sweden)
A. M. de Paor
1998-01-01
Full Text Available Hide (Nonlinear Processes in Geophysics, 1998 has produced a new mathematical model of a self-exciting homopolar dynamo driving a series- wound motor, as a continuing contribution to the theory of the geomagnetic field. By a process of exact perturbation analysis, followed by combination and partial solution of differential equations, the complete nonlinear quenching of current fluctuations reported by Hide in the case that a parameter ε has the value 1 is proved via the Popov theorem from feedback system stability theory.
13. Spiral-wave dynamics in excitable medium with excitability modulated by rectangle wave
International Nuclear Information System (INIS)
Yuan Guo-Yong
2011-01-01
We numerically study the dynamics of spiral waves in the excitable system with the excitability modulated by a rectangle wave. The tip trajectories and their variations with the modulation period T are explained by the corresponding spectrum analysis. For a large T, the external modulation leads to the occurrence of more frequency peaks and these frequencies change with the modulation period according to their specific rules, respectively. Some of the frequencies and a primary frequency f 1 determine the corresponding curvature periods, which are locked into rational multiplies of the modulation period. These frequency-locking behaviours and the limited life-span of the frequencies in their variations with the modulation period constitute many resonant entrainment bands in the T axis. In the main bands, which follow the relation T/T 12 = m/n, the size variable R x of the tip trajectory is a monotonic increasing function of T. The rest of the frequencies are linear combinations of the two ones. Due to the complex dynamics, many unique tip trajectories appear at some certain T. We find also that spiral waves are eliminated when T is chosen from the end of the main resonant bands. This offers a useful method of controling the spiral wave. (general)
14. Low-energy scattering of excited helium atoms by rare gases
International Nuclear Information System (INIS)
Peach, G.
1978-01-01
The construction of semi-empirical model potentials for systems composed of helium in an excited state (Hestar) and a rare-gas atom (He or Ne) is described. The model of the atom-atom pair which has been adopted is one in which the excited electron is included explicitly, but the residual He + ion and the rare-gas atom are treated simply as cores which may be polarised. The results obtained are in satisfactory agreement with other calculations where they are available. (author)
15. Femtosecond laser excitation of dielectric materials
DEFF Research Database (Denmark)
Wædegaard, Kristian Juncher; Balling, Peter; Frislev, Martin Thomas
2012-01-01
We report an approach to modeling the interaction between ultrashort laser pulses and dielectric materials. The model includes the excitation of carriers by the laser through strongfield excitation, collisional excitation, and absorption in the plasma consisting of conduction-band electrons formed...
16. Equations for the kinetic modeling of supersonically flowing electrically excited lasers
International Nuclear Information System (INIS)
Lind, R.C.
1973-01-01
The equations for the kinetic modeling of a supersonically flowing electrically excited laser system are presented. The work focuses on the use of diatomic gases, in particular carbon monoxide mixtures. The equations presented include the vibrational rate equation which describes the vibrational population distribution, the electron, ion and electronic level rate equations, the gasdynamic equations for an ionized gas in the presence of an applied electric field, and the free electron Boltzmann equation including flow and gradient coupling terms. The model developed accounts for vibration--vibration collisions, vibration-translation collisions, electron-molecule inelastic excitation and superelastic de-excitation collisions, charge particle collisions, ionization and three body recombination collisions, elastic collisions, and radiative decay, all of which take place in such a system. A simplified form of the free electron Boltzmann equation is developed and discussed with emphasis placed on its coupling with the supersonic flow. A brief description of a possible solution procedure for the set of coupled equations is discussed
17. Thermodynamical description of excited nuclei
International Nuclear Information System (INIS)
Bonche, P.
1989-01-01
In heavy ion collisions it has been possible to obtain composite systems at rather high excitation energies corresponding to temperatures of several MeV. The theoretical studies of these systems are based on concepts borrowed from thermodynamics or statistical physics, such as the temperature. In these lectures, we present the concepts of statistical physics which are involved in the physics of heavy ion as they are produced nowadays in the laboratory and also during the final stage of a supernova collapse. We do not attempt to describe the reaction mechanisms which yield such nuclear systems nor their decay by evaporation or fragmentation. We shall only study their static properties. The content of these lectures is organized in four main sections. The first one gives the basic features of statistical physics and thermodynamics necessary to understand quantum mechanics at finite temperature. In the second one, we present a study of the liquid-gas phase transition in nuclear physics. A phenomenological approach of the stability of hot nuclei follows. The microscopic point of view is proposed in the third part. Starting from the basic concepts derived in the first part, it provides a description of excited or hot nuclei which confirms the qualitative results of the second part. Furthermore it gives a full description of most properties of these nuclei as a function of temperature. Finally in the last part, a microscopic derivation of the equation of state of nuclear matter is proposed to study the collapse of a supernova core
18. Trapping time statistics and efficiency of transport of optical excitations in dendrimers
Science.gov (United States)
Heijs, Dirk-Jan; Malyshev, Victor A.; Knoester, Jasper
2004-09-01
We theoretically study the trapping time distribution and the efficiency of the excitation energy transport in dendritic systems. Trapping of excitations, created at the periphery of the dendrimer, on a trap located at its core, is used as a probe of the efficiency of the energy transport across the dendrimer. The transport process is treated as incoherent hopping of excitations between nearest-neighbor dendrimer units and is described using a rate equation. We account for radiative and nonradiative decay of the excitations while diffusing across the dendrimer. We derive exact expressions for the Laplace transform of the trapping time distribution and the efficiency of trapping, and analyze those for various realizations of the energy bias, number of dendrimer generations, and relative rates for decay and hopping. We show that the essential parameter that governs the trapping efficiency is the product of the on-site excitation decay rate and the trapping time (mean first passage time) in the absence of decay.
19. Magnetic excitations in (VO)HPO4· 1/2 H2O
International Nuclear Information System (INIS)
Garrett, A.W.; Nagler, S.E.; Tennant, D.A.
1997-01-01
The magnetic excitations of an antiferromagnetic spin dimer system, (VO)HPO 4 · 1/2 H 2 O, are examined using inelastic neutron scattering. A dispersionless mode is found, consistent with expectations for a dimer excitation. The intensity variation of the mode reveals a V 4+ - V 4+ dimer separation of 4.43 angstrom, almost 50% larger than the originally expected length
20. Backreaction of excitations on a vortex
OpenAIRE
1996-01-01
Excitations of a vortex are usually considered in a linear approximation neglecting their backreaction on the vortex. In the present paper we investigate backreaction of Proca type excitations on a straightlinear vortex in the Abelian Higgs model. We propose exact Ansatz for fields of the excited vortex. From initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the backreaction corrections. Their approximate solutions are found ...
1. Nonlinear Dynamic Behavior of a Flexible Structure to Combined External Acoustic and Parametric Excitation
Directory of Open Access Journals (Sweden)
Paulo S. Varoto
2006-01-01
Full Text Available Flexible structures are frequently subjected to multiple inputs when in the field environment. The accurate determination of the system dynamic response to multiple inputs depends on how much information is available from the excitation sources that act on the system under study. Detailed information include, but are not restricted to appropriate characterization of the excitation sources in terms of their variation in time and in space for the case of distributed loads. Another important aspect related to the excitation sources is how inputs of different nature contribute to the measured dynamic response. A particular and important driving mechanism that can occur in practical situations is the parametric resonance. Another important input that occurs frequently in practice is related to acoustic pressure distributions that is a distributed type of loading. In this paper, detailed theoretical and experimental investigations on the dynamic response of a flexible cantilever beam carrying a tip mass to simultaneously applied external acoustic and parametric excitation signals have been performed. A mathematical model for transverse nonlinear vibration is obtained by employing Lagrange’s equations where important nonlinear effects such as the beam’s curvature and quadratic viscous damping are accounted for in the equation of motion. The beam is driven by two excitation sources, a sinusoidal motion applied to the beam’s fixed end and parallel to its longitudinal axis and a distributed sinusoidal acoustic load applied orthogonally to the beam’s longitudinal axis. The major goal here is to investigate theoretically as well as experimentally the dynamic behavior of the beam-lumped mass system under the action of these two excitation sources. Results from an extensive experimental work show how these two excitation sources interacts for various testing conditions. These experimental results are validated through numerically simulated results
2. A large electrically excited synchronous generator
DEFF Research Database (Denmark)
2014-01-01
This invention relates to a large electrically excited synchronous generator (100), comprising a stator (101), and a rotor or rotor coreback (102) comprising an excitation coil (103) generating a magnetic field during use, wherein the rotor or rotor coreback (102) further comprises a plurality...... adjacent neighbouring poles. In this way, a large electrically excited synchronous generator (EESG) is provided that readily enables a relatively large number of poles, compared to a traditional EESG, since the excitation coil in this design provides MMF for all the poles, whereas in a traditional EESG...... each pole needs its own excitation coil, which limits the number of poles as each coil will take up too much space between the poles....
3. Composite model describing the excitation and de-excitation of nitrogen by an electron beam
International Nuclear Information System (INIS)
Kassem, A.E.; Hickman, R.S.
1975-01-01
Based on recent studies, the effect of re-excited ions in the emission of electron beam induced fluorescence in nitrogen has been estimated. These effects are included in the formulation of a composite model describing the excitation and de-excitation of nitrogen by an electron beam. The shortcomings of previous models, namely the dependence of the measured temperature on true gas temperature as well as the gas density, are almost completely eliminated in the range of temperatures and densities covered by the available data. (auth)
4. Energy dependence of the ionization of highly excited atoms by collisions with excited atoms
International Nuclear Information System (INIS)
Shirai, T.; Nakai, Y.; Nakamura, H.
1979-01-01
Approximate analytical expressions are derived for the ionization cross sections in the high- and low-collision-energy limits using the improved impulse approximation based on the assumption that the electron-atom inelastic-scattering amplitude is a function only of the momentum transfer. Both cases of simultaneous excitation and de-excitation of one of the atoms are discussed. The formulas are applied to the collisions between two excited hydrogen atoms and are found very useful for estimating the cross sections in the wide range of collisions energies
5. Isotope separation using vibrationally excited molecules
International Nuclear Information System (INIS)
Woodroffe, J.A.; Keck, J.C.
1979-01-01
Vibrational excitation of molecules having components of a selected isotope type is used to produce a conversion from vibrational to translational excitation of the molecules by collision with the molecules of a heavy carrier gas. The resulting difference in translaton between the molecules of the selected isotope type and all other molecules of the same compound permits their separate collection. When applied to uranium enrichment, a subsonic cryogenic flow of molecules of uranium hexafluoride in combination with an argon carrier gas is directed through a cooled chamber that is illuminated by laser radiaton tuned to vibrationally excite the uranium hexafluoride molecules of a specific uranium isotope. The excited molecules collide with carrier gas molecules, causing a conversion of the excitation energy into a translation of the excited molecule, which results in a higher thermal energy or diffusivity than that of the other uranium hexafluoride molecules. The flowing molecules including the excited molecules directly enter a set of cryogenically cooled channels. The higher thermal velocity of the excited molecules increases the probability of their striking a collector surface. The molecules which strike this surface immediately condense. After a predetermined thickness of molecules is collected on the surface, the flow of uranium hexafluoride is interrupted and the chamber heated to the point of vaporization of the collected hexafluoride, permitting its removal. (LL)
6. Stochastic resonance and vibrational resonance in an excitable system: The golden mean barrier
International Nuclear Information System (INIS)
Stan, Cristina; Cristescu, C.P.; Alexandroaei, D.; Agop, M.
2009-01-01
We report on stochastic resonance and vibrational resonance in an electric charge double layer configuration as usually found in electrical discharges, biological cell membranes, chemical systems and nanostructures. The experiment and numerical computation show the existence of a barrier expressible in terms of the golden mean above which the two phenomena do not take place. We consider this as new evidence for the importance of the golden mean criticality in the oscillatory dynamics, in agreement with El Naschie's E-infinity theory. In our experiment, the dynamics of a charge double layer generated in the inter-anode space of a twin electrical discharge is investigated under noise-harmonic and harmonic-harmonic perturbations. In the first case, a Gaussian noise can enhance the response of the system to a weak injected periodic signal, a clear mark of stochastic resonance. In the second case, similar enhancement can appear if the noise is replaced by a harmonic perturbation with a frequency much higher than the frequency of the weak oscillation. The amplitude of the low frequency oscillation shows a maximum versus the amplitude of the high frequency perturbation demonstrating vibrational resonance. In order to model these dynamics, we derived an excitable system by modifying a biased van der Pol oscillator. The computational study considers the behaviour of this system under the same types of perturbation as in the experimental investigations and is found to give consistent results in both situations.
7. Excitation of resonances of microspheres on an optical fiber
Science.gov (United States)
Serpengüzel, A.; Arnold, S.; Griffel, G.
1995-04-01
Morphology-dependent resonances (MDR's) of solid microspheres are excited by using an optical fiber coupler. The narrowest measured MDR linewidths are limited by the excitation laser linewidth ( < 0.025 nm). Only MDR's, with an on-resonance to off-resonance intensity ratio of 104, contribute to scattering. The intensity of various resonance orders is understood by the localization principle and the recently developed generalized Lorentz-Mie theory. The microsphere fiber system has potential for becoming a building block in dispersive microphotonics. The basic physics underlying our approach may be considered a harbinger for the coupling of active photonic microstructures such as microdisk lasers.
8. Holonomic Quantum Control by Coherent Optical Excitation in Diamond
Energy Technology Data Exchange (ETDEWEB)
Zhou, Brian B.; Jerger, Paul C.; Shkolnikov, V. O.; Heremans, F. Joseph; Burkard, Guido; Awschalom, David D.
2017-10-01
Although geometric phases in quantum evolution are historically overlooked, their active control now stimulates strategies for constructing robust quantum technologies. Here, we demonstrate arbitrary singlequbit holonomic gates from a single cycle of nonadiabatic evolution, eliminating the need to concatenate two separate cycles. Our method varies the amplitude, phase, and detuning of a two-tone optical field to control the non-Abelian geometric phase acquired by a nitrogen-vacancy center in diamond over a coherent excitation cycle. We demonstrate the enhanced robustness of detuned gates to excited-state decoherence and provide insights for optimizing fast holonomic control in dissipative quantum systems.
9. Holonomic Quantum Control by Coherent Optical Excitation in Diamond.
Science.gov (United States)
Zhou, Brian B; Jerger, Paul C; Shkolnikov, V O; Heremans, F Joseph; Burkard, Guido; Awschalom, David D
2017-10-06
Although geometric phases in quantum evolution are historically overlooked, their active control now stimulates strategies for constructing robust quantum technologies. Here, we demonstrate arbitrary single-qubit holonomic gates from a single cycle of nonadiabatic evolution, eliminating the need to concatenate two separate cycles. Our method varies the amplitude, phase, and detuning of a two-tone optical field to control the non-Abelian geometric phase acquired by a nitrogen-vacancy center in diamond over a coherent excitation cycle. We demonstrate the enhanced robustness of detuned gates to excited-state decoherence and provide insights for optimizing fast holonomic control in dissipative quantum systems.
10. Interqubit coupling mediated by a high-excitation-energy quantum object
NARCIS (Netherlands)
Ashhab, S.; Niskanen, A.O.; Harrabi, K.; Nakamura, Y.; Picot, T.; De Groot, P.C.; Harmans, C.J.P.M.; Mooij, J.E.; Nori, F.
2008-01-01
We consider a system composed of two qubits and a high excitation energy quantum object used to mediate coupling between the qubits. We treat the entire system quantum mechanically and analyze the properties of the eigenvalues and eigenstates of the total Hamiltonian. After reproducing well known
11. Localized excitations and the geometry of the 1nπ* excited states of pyrazine
International Nuclear Information System (INIS)
Kleier, D.A.; Martin, R.L.; Wadt, W.R.; Moomaw, W.R.
1982-01-01
Previous theoretical work has shown that the lowest excited singlet state of pyrazine, the π* 1 B 3 u state, is best described in terms of interacting excitations localized on each nitrogen. The present work refines the localized excitation model and considers its implications for the geometry of the 1 B 3 u state. Hartree-Fock calculations show that the best single configuration description of the nπ* state has broken ( 1 B 1 ) symmetry with the excitation strongly localized at one end of the molcule. If the symmetry-restricted hf result is used for reference, this localization describes an important correlation effect. The excited-state geometry was probed using configuration interaction wave functions based on the symmetry-restricted orbitals, as well as properly symmetrized ''valance-bond'' wave functions based on the broken symmetry solutions. Both descriptions lead to a very flat potential for a b/sub 1u/ vibrational mode. This mode reduces the molecular geometry from D/sub 2h/ to C/sub 2v/. We present spectroscopic evidence of our own and of other workers which is consistent with such a flat potential
12. General theory of excitation energy transfer in donor-mediator-acceptor systems.
Science.gov (United States)
Kimura, Akihiro
2009-04-21
General theory of the excitation energy transfer (EET) in the case of donor-mediator-acceptor system was constructed by using generalized master equation (GME). In this theory, we consider the direct and indirect transitions in the EET consistently. Hence, our theory includes the quantum mechanical interference between the direct and indirect transitions automatically. Memory functions in the GME were expressed by the overlap integrals among the time-dependent emission spectrum of the donor, the absorption spectrum of the mediator, the time-dependent emission spectrum of the mediator, and the absorption spectrum of the acceptor. In the Markov limit of the memory functions, we obtained the rate of EET which consists of three terms due to the direct transition, the indirect transition, and the interference between them. We found that the interference works effectively in the limit of slow thermalization at the intermediate state. The formula of EET rate in this limit was expressed by the convolution of the EET interaction and optical spectra. The interference effect strongly depends on the width of the absorption spectrum of mediator molecule and the energy gap between the donor and the mediator molecules.
13. Inelastic scattering of 9Li and excitation mechanism of its first excited state
International Nuclear Information System (INIS)
Al Falou, H.; Kanungo, R.; Andreoiu, C.; Cross, D.S.; Davids, B.; Djongolov, M.; Gallant, A.T.; Galinski, N.; Howell, D.; Kshetri, R.; Niamir, D.; Orce, J.N.; Shotter, A.C.; Sjue, S.; Tanihata, I.; Thompson, I.J.; Triambak, S.; Uchida, M.; Walden, P.; Wiringa, R.B.
2013-01-01
The first measurement of inelastic scattering of 9 Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. The quadrupole deformation parameter is extracted from an analysis of the angular distribution
14. VUV Study of Electron-Pyrimidine Dissociative Excitation
Science.gov (United States)
Hein, Jeff; Al-Khazraji, Hajar; Tiessen, Collin; Lukic, Dragan; Trocchi, Joshuah; McConkey, William
2013-05-01
A crossed electron-gas beam system coupled to a VUV spectrometer has been used to investigate the dissociation of pyrimidine (C4H4N2) into excited atomic fragments in the electron-impact energy range from threshold to 375 eV. Data have been made absolute using Lyman- α from H2 as a secondary standard. The main features in the spectrum are the H Lyman series lines. The emission cross section of Lyman- α is measured to be (2.44 +/- 0.25) 10-18 cm2 at 100 eV impact energy. The probability of extracting C or N atoms from the ring is shown to be very small. Possible dissociation channels and excitation mechanisms in the parent molecule will be discussed. The authors thank NSERC (Canada) for financial support.
15. Multiple excitation regenerative amplifier inertial confinement system
International Nuclear Information System (INIS)
George, V.E.; Haas, R.A.; Krupke, W.F.; Schlitt, L.G.
1980-01-01
The invention relates to apparatus and methods for producing high intensity laser radiation generation which is achieved through an optical amplifier-storage ring design. One or two synchronized, counterpropagating laser pulses are injected into a regenerative amplifier cavity and amplified by gain media which are pumped repetitively by electrical or optical means. The gain media excitation pulses are tailored to efficiently amplify the laser pulses during each transit. After the laser pulses have been amplified to the desired intensity level, they are either switched out of the cavity by some switch means, as for example an electro-optical device, for any well known laser end uses, or a target means may be injected into the regenerative amplifier cavity in such a way as to intercept simultaneously the counterpropagating laser pulses. One such well known end uses to which this invention is intended is for production of high density and temperature plasmas suitable for generating neutrons, ions and x-rays and for studying matter heated by high intensity laser radiation
16. Application brushless machines with combine excitation for a hybrid car and an electric car
OpenAIRE
GANDZHA S.A.; KIESSH I.E.
2015-01-01
This article shows advantages of application the brushless machines with combined excitation (excitation from permanent magnets and excitation winding) for the hybrid car and the electric car. This type of electric machine is compared with a typical brushless motor and an induction motor. The main advantage is the decrease of the dimensions of electric machine and the reduction of the price for an electronic control system. It is shown the design and the principle of operation of the electric...
17. Statistics of excitations in the electron glass model
Science.gov (United States)
Palassini, Matteo
2011-03-01
We study the statistics of elementary excitations in the classical electron glass model of localized electrons interacting via the unscreened Coulomb interaction in the presence of disorder. We reconsider the long-standing puzzle of the exponential suppression of the single-particle density of states near the Fermi level, by measuring accurately the density of states of charged and electron-hole pair excitations via finite temperature Monte Carlo simulation and zero-temperature relaxation. We also investigate the statistics of large charge rearrangements after a perturbation of the system, which may shed some light on the slow relaxation and glassy phenomena recently observed in a variety of Anderson insulators. In collaboration with Martin Goethe.
18. Excitation of Ion Cyclotron Waves by Ion and Electron Beams in Compensated-current System
Science.gov (United States)
Xiang, L.; Wu, D. J.; Chen, L.
2018-04-01
Ion cyclotron waves (ICWs) can play important roles in the energization of plasma particles. Charged particle beams are ubiquitous in space, and astrophysical plasmas and can effectively lead to the generation of ICWs. Based on linear kinetic theory, we consider the excitation of ICWs by ion and electron beams in a compensated-current system. We also investigate the competition between reactive and kinetic instabilities. The results show that ion and electron beams both are capable of generating ICWs. For ICWs driven by ion beams, there is a critical beam velocity, v bi c , and critical wavenumber, k z c , for a fixed beam density; the reactive instability dominates the growth of ICWs when the ion-beam velocity {v}{bi}> {v}{bi}c and the wavenumber {k}zz≃ 2{k}zc/3 for a given {v}{bi}> {v}{bi}c. For the slow ion beams with {v}{bi}< {v}{bi}c, the kinetic instability can provide important growth rates of ICWs. On the other hand, ICWs driven by electron beams are excited only by the reactive instability, but require a critical velocity, {v}{be}c\\gg {v}{{A}} (the Alfvén velocity). In addition, the comparison between the approximate analytical results based on the kinetic theory and the exact numerical calculation based on the fluid model demonstrates that the reactive instabilities can well agree quantitatively with the numerical results by the fluid model. Finally, some possible applications of the present results to ICWs observed in the solar wind are briefly discussed.
19. Exciplex ensemble modulated by excitation mode in intramolecular charge-transfer dyad: effects of temperature, solvent polarity, and wavelength on photochemistry and photophysics of tethered naphthalene-dicyanoethene system.
Science.gov (United States)
Aoki, Yoshiaki; Matsuki, Nobuo; Mori, Tadashi; Ikeda, Hiroshi; Inoue, Yoshihisa
2014-09-19
Solvent, temperature, and excitation wavelength significantly affected the photochemical outcomes of a naphthalene-dicyanoethene system tethered by different number (n) of methylene groups (1-3). The effect of irradiation wavelength was almost negligible for 2a but pronounced for 3a. The temperature dependence and theoretical calculations indicated the diversity of exciplex conformations, an ensemble of which can be effectively altered by changing excitation wavelength to eventually switch the regioselectivity of photoreactions.
20. Calibrated Noncontact Exciters for Optical Modal Analysis
Directory of Open Access Journals (Sweden)
Henrik O. Saldner
1996-01-01
Full Text Available Two types of exciters were investigated experimentally One of the exciters uses a small permanent magnet fastened on the object. The force is introduced by the change in the electromagnetic field from a coil via an air gap. The second exciter is an eddy-current electromagnet one. The amplitude of the forces from these exciters are calibrated by using dynamic reciprocity in conjunction with electronic holography. These forces strongly depend upon the distance between the exciter and the object.
1. Chemical modulation of electronic structure at the excited state
Science.gov (United States)
Li, F.; Song, C.; Gu, Y. D.; Saleem, M. S.; Pan, F.
2017-12-01
Spin-polarized electronic structures are the cornerstone of spintronics, and have thus attracted a significant amount of interest; in particular, researchers are looking into how to modulate the electronic structure to enable multifunctional spintronics applications, especially in half-metallic systems. However, the control of the spin polarization has only been predicted in limited two-dimensional systems with spin-polarized Dirac structures and is difficult to achieve experimentally. Here, we report the modulation of the electronic structure in the light-induced excited state in a typical half-metal, L a1 /2S r1 /2Mn O3 -δ . According to the spin-transport measurements, there appears a light-induced increase in magnetoresistance due to the enhanced spin scattering, which is closely associated with the excited spin polarization. Strikingly, the light-induced variation can be enhanced via alcohol processing and reduced by oxygen annealing. X-ray photoelectron spectroscopy measurements show that in the chemical process, a redox reaction occurs with a change in the valence of Mn. Furthermore, first-principles calculations reveal that the change in the valence of Mn alters the electronic structure and consequently modulates the spin polarization in the excited state. Our findings thus report a chemically tunable electronic structure, demonstrating interesting physics and the potential for multifunctional applications and ultrafast spintronics.
2. Use of polarization measurements in evaluating cascade contributions to optical excitation functions
International Nuclear Information System (INIS)
McConkey, J.W.
1981-01-01
Recent developments in theory and experimental measurements of rotational line polarization fractions of diatomic molecules following electron impact are used to show how in some instances cascade free optical excitation functions can be derived without additional measurements of the cascading contribution. The Lyman system of H 2 is presented as an example and some previously conflicting excitation cross-section measurements obtained by different techniques are reconciled
3. Linear and nonlinear excitations in two stacks of parallel arrays of long Josephson junctions
DEFF Research Database (Denmark)
Carapella, G.; Constabile, Giovanni; Latempa, R.
2000-01-01
We investigate a structure consisting of two parallel arrays of long Josephson junctions sharing a common electrode that allows inductive coupling between the arrays. A model for this structure is derived starting from the description of its continuous limit. The excitation of linear cavity modes...... known from continuous and discrete systems as well as the excitation of a new state exhibiting synchronization in two dimensions are inferred from the mathematical model of the system. The stable nonlinear solution of the coupled sine-Gordon equations describing the system is found to consist...
4. A current-excited triple-time-voltage oversampling method for bio-impedance model for cost-efficient circuit system.
Science.gov (United States)
Yan Hong; Yong Wang; Wang Ling Goh; Yuan Gao; Lei Yao
2015-08-01
This paper presents a mathematic method and a cost-efficient circuit to measure the value of each component of the bio-impedance model at electrode-electrolyte interface. The proposed current excited triple-time-voltage oversampling (TTVO) method deduces the component values by solving triple simultaneous electric equation (TSEE) at different time nodes during a current excitation, which are the voltage functions of time. The proposed triple simultaneous electric equations (TSEEs) allows random selections of the time nodes, hence numerous solutions can be obtained during a single current excitation. Following that, the oversampling approach is engaged by averaging all solutions of multiple TSEEs acquired after a single current excitation, which increases the practical measurement accuracy through the improvement of the signal-to-noise ratio (SNR). In addition, a print circuit board (PCB) that consists a switched current exciter and an analog-to-digital converter (ADC) is designed for signal acquisition. This presents a great cost reduction when compared against other instrument-based measurement data reported [1]. Through testing, the measured values of this work is proven to be in superb agreements on the true component values of the electrode-electrolyte interface model. This work is most suited and also useful for biological and biomedical applications, to perform tasks such as stimulations, recordings, impedance characterizations, etc.
5. System and method for controlling depth of imaging in tissues using fluorescence microscopy under ultraviolet excitation following staining with fluorescing agents
Science.gov (United States)
Levenson, Richard; Demos, Stavros
2018-05-08
A method is disclosed for analyzing a thin tissue sample and adapted to be supported on a slide. The tissue sample may be placed on a slide and exposed to one or more different exogenous fluorophores excitable in a range of about 300 nm-200 nm, and having a useful emission band from about 350 nm-900 nm, and including one or more fluorescent dyes or fluorescently labeled molecular probes that accumulate in tissue or cellular components. The fluorophores may be excited with a first wavelength of UV light between about 200 nm-290 nm. An optical system collects emissions from the fluorophores at a second wavelength, different from the first wavelength, which are generated in response to the first wavelength of UV light, to produce an image for analysis.
6. Back reaction of excitations on a vortex
Science.gov (United States)
1997-01-01
Excitations of a vortex are usually considered in a linear approximation neglecting their back reaction on the vortex. In the present paper we investigate back reaction of Proca-type excitations on a straight linear vortex in the Abelian Higgs model. We propose an exact ansatz for fields of the excited vortex. From an initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the back reaction corrections. Their approximate solutions are found in the cases of plane wave and wave-packet-type excitations. We find that the excited vortex radiates the vector field and that the Higgs field has a very broad oscillating component.
7. Theory of superconductivity and spin excitations in cuprates
Science.gov (United States)
Plakida, Nikolay M.
2018-06-01
A microscopic theory of high-temperature superconductivity in strongly correlated systems as cuprates is presented. The two-subband extended Hubbard model is considered where the intersite Coulomb repulsion and electron-phonon interaction are taken into account. The low-energy spin excitations are considered within the t-J model.
8. Continuum emission of excited sodium dimer
International Nuclear Information System (INIS)
Pardo, A.; Poyato, J.M.L.; Alonso, J.I.; Rico, F.R.
1980-01-01
A study has been made of the behaviour of excited molecular sodium using high-power Ar + laser radiation. A continuum emission was observed in the red wavelength region. This emission was thought to be caused by the formation of excited triatomic molecules. Energy transfer was observed from excited molecules to atoms. (orig.)
9. Voiced Excitations
National Research Council Canada - National Science Library
Holzricher, John
2004-01-01
To more easily obtain a voiced excitation function for speech characterization, measurements of skin motion, tracheal tube, and vocal fold, motions were made and compared to EM sensor-glottal derived...
10. Numerical prediction analysis of propeller exciting force for hull–propeller–rudder system in oblique flow
Directory of Open Access Journals (Sweden)
Shuai Sun
2018-01-01
Full Text Available In order to analyze the characteristics of propeller exciting force, the hybrid grid is adopted and the numerical prediction of KCS ship model is performed for hull–propeller–rudder system by Reynolds-Averaged Navier Stokes (RANS method and volume of fluid (VOF model. Firstly, the numerical simulation of hydrodynamics for bare hull at oblique state is carried out. The results show that with the increasing of the drift angle, the coefficients of resistance, side force and yaw moment are constantly increasing, and the bigger the drift angle, the worse the overall uniformity of propeller disk. Then, propeller bearing force for hull–propeller–rudder system in oblique flow is calculated. It is found that the propeller thrust and torque fluctuation coefficient peak in drift angle are greater than that in straight line navigation, and the negative drift angle is greater than the positive. The fluctuation peak variation law of coefficient of side force and bending moment are different due to various causes.
11. Complete fusion excitation function for the 16O + natS reaction
International Nuclear Information System (INIS)
Wang Sufang; Zheng Jiwen; Liu Guoxing
1994-01-01
The complete fusion excitation function for the 16 O + nat S reaction has been measured in the range of 50-75 MeV with a step of 1.0 MeV by using a position sensitive ΔE-E telescope system. The model parameters have been extracted from data analysis. The striking gross structure of the excitation function has been observed. The energies of peaks are at E CM 38,43 and 48 MeV respectively
12. The study of excited oxygen molecule gas species production and quenching on thermal protection system materials
Science.gov (United States)
Nordine, Paul C.; Fujimoto, Gordon T.; Greene, Frank T.
1987-01-01
The detection of excited oxygen and ozone molecules formed by surface catalyzed oxygen atom recombination and reaction was investigated by laser induced fluorescence (LIF), molecular beam mass spectrometric (MBMS), and field ionization (FI) techniques. The experiment used partially dissociated oxygen flows from a microwave discharge at pressures in the range from 60 to 400 Pa or from an inductively coupled RF discharge at atmospheric pressure. The catalyst materials investigated were nickel and the reaction cured glass coating used for Space Shuttle reusable surface insulation tiles. Nonradiative loss processes for the laser excited states makes LIF detection of O2 difficult such that formation of excited oxygen molecules could not be detected in the flow from the microwave discharge or in the gaseous products of atom loss on nickel. MBMS experiments showed that ozone was a product of heterogeneous O atom loss on nickel and tile surfaces at low temperatures and that ozone is lost on these materials at elevated temperatures. FI was separately investigated as a method by which excited oxygen molecules may be conveniently detected. Partial O2 dissociation decreases the current produced by FI of the gas.
13. Nonlinear excitation fluorescence microscopy: source considerations for biological applications
Science.gov (United States)
Wokosin, David L.
2008-02-01
Ultra-short-pulse solid-state laser sources have improved contrast within fluorescence imaging and also opened new windows of investigation in biological imaging applications. Additionally, the pulsed illumination enables harmonic scattering microscopy which yields intrinsic structure, symmetry and contrast from viable embryos, cells and tissues. Numerous human diseases are being investigated by the combination of (more) intact dynamic tissue imaging of cellular function with gene-targeted specificity and electrophysiology context. The major limitation to more widespread use of multi-photon microscopy has been the complete system cost and added complexity above and beyond commercial camera and confocal systems. The current status of all-solid-state ultrafast lasers as excitation sources will be reviewed since these lasers offer tremendous potential for affordable, reliable, "turnkey" multiphoton imaging systems. This effort highlights the single box laser systems currently commercially available, with defined suggestions for the ranges for individual laser parameters as derived from a biological and fluorophore limited perspective. The standard two-photon dose is defined by 800nm, 10mW, 200fs, and 80Mhz - at the sample plane for tissue culture cells, i.e. after the full scanning microscope system. Selected application-derived excitation wavelengths are well represented by 700nm, 780nm, ~830nm, ~960nm, 1050nm, and 1250nm. Many of the one-box lasers have fixed or very limited excitation wavelengths available, so the lasers will be lumped near 780nm, 800nm, 900nm, 1050nm, and 1250nm. The following laser parameter ranges are discussed: average power from 200mW to 2W, pulse duration from 70fs to 700fs, pulse repetition rate from 20MHz to 200MHz, with the laser output linearly polarized with an extinction ratio at least 100:1.
14. Two-photon excitation of argon
International Nuclear Information System (INIS)
Pindzola, P.S.; Payne, M.C.
1982-01-01
The authors calculate two photon excitation parameters for various excited states of argon assuming the absorption of near resonance broad-bandwidth laser radiation. Results are given for the case of two photons absorbed for the same laser beam as well as the case of absorbing photons of different frequency from each of two laser beams. The authors use multiconfiguration Hartree-Fock wave functions to evaluate the second-order sums over matrix elements. Various experimental laser schemes are suggested for the efficient excitation and subsequent ionization of argon
15. Excited state Intramolecular Proton Transfer in Anthralin
DEFF Research Database (Denmark)
Møller, Søren; Andersen, Kristine B.; Spanget-Larsen, Jens
1998-01-01
Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results in an unus......Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results......, associated with an excited-state intramolecular proton transfer process....
16. 48-spot single-molecule FRET setup with periodic acceptor excitation
Science.gov (United States)
Ingargiola, Antonino; Segal, Maya; Gulinatti, Angelo; Rech, Ivan; Labanca, Ivan; Maccagnani, Piera; Ghioni, Massimo; Weiss, Shimon; Michalet, Xavier
2018-03-01
Single-molecule Förster resonance energy transfer (smFRET) allows measuring distances between donor and acceptor fluorophores on the 3-10 nm range. Solution-based smFRET allows measurement of binding-unbinding events or conformational changes of dye-labeled biomolecules without ensemble averaging and free from surface perturbations. When employing dual (or multi) laser excitation, smFRET allows resolving the number of fluorescent labels on each molecule, greatly enhancing the ability to study heterogeneous samples. A major drawback to solution-based smFRET is the low throughput, which renders repetitive measurements expensive and hinders the ability to study kinetic phenomena in real-time. Here we demonstrate a high-throughput smFRET system that multiplexes acquisition by using 48 excitation spots and two 48-pixel single-photon avalanche diode array detectors. The system employs two excitation lasers allowing separation of species with one or two active fluorophores. The performance of the system is demonstrated on a set of doubly labeled double-stranded DNA oligonucleotides with different distances between donor and acceptor dyes along the DNA duplex. We show that the acquisition time for accurate subpopulation identification is reduced from several minutes to seconds, opening the way to high-throughput screening applications and real-time kinetics studies of enzymatic reactions such as DNA transcription by bacterial RNA polymerase.
17. Back reaction of excitations on a vortex
International Nuclear Information System (INIS)
1997-01-01
Excitations of a vortex are usually considered in a linear approximation neglecting their back reaction on the vortex. In the present paper we investigate back reaction of Proca-type excitations on a straight linear vortex in the Abelian Higgs model. We propose an exact ansatz for fields of the excited vortex. From an initial set of six nonlinear field equations we obtain (in a limit of weak excitations) two linear wave equations for the back reaction corrections. Their approximate solutions are found in the cases of plane wave and wave-packet-type excitations. We find that the excited vortex radiates the vector field and that the Higgs field has a very broad oscillating component. copyright 1997 The American Physical Society
18. Complex dynamics of an archetypal self-excited SD oscillator driven by moving belt friction
International Nuclear Information System (INIS)
Li Zhi-Xin; Cao Qing-Jie; Alain, Léger
2016-01-01
We propose an archetypal self-excited system driven by moving belt friction, which is constructed with the smooth and discontinuous (SD) oscillator proposed by the Cao et al. and the classical moving belt. The moving belt friction is modeled as the Coulomb friction to formulate the mathematical model of the proposed self-excited SD oscillator. The equilibrium states of the unperturbed system are obtained to show the complex equilibrium bifurcations. Phase portraits are depicted to present the hyperbolic structure transition, the multiple stick regions, and the friction-induced asymmetry phenomena. The numerical simulations are carried out to demonstrate the friction-induced vibration of multiple stick-slip phenomena and the stick-slip chaos in the perturbed self-excited system. The results presented here provide an opportunity for us to get insight into the mechanism of the complex friction-induced nonlinear dynamics in mechanical engineering and geography. (paper)
19. Probing thermomechanics at the nanoscale: impulsively excited pseudosurface acoustic waves in hypersonic phononic crystals.
Science.gov (United States)
Nardi, Damiano; Travagliati, Marco; Siemens, Mark E; Li, Qing; Murnane, Margaret M; Kapteyn, Henry C; Ferrini, Gabriele; Parmigiani, Fulvio; Banfi, Francesco
2011-10-12
High-frequency surface acoustic waves can be generated by ultrafast laser excitation of nanoscale patterned surfaces. Here we study this phenomenon in the hypersonic frequency limit. By modeling the thermomechanics from first-principles, we calculate the system's initial heat-driven impulsive response and follow its time evolution. A scheme is introduced to quantitatively access frequencies and lifetimes of the composite system's excited eigenmodes. A spectral decomposition of the calculated response on the eigemodes of the system reveals asymmetric resonances that result from the coupling between surface and bulk acoustic modes. This finding allows evaluation of impulsively excited pseudosurface acoustic wave frequencies and lifetimes and expands our understanding of the scattering of surface waves in mesoscale metamaterials. The model is successfully benchmarked against time-resolved optical diffraction measurements performed on one-dimensional and two-dimensional surface phononic crystals, probed using light at extreme ultraviolet and near-infrared wavelengths.
20. Electroluminescence from graphene excited by electron tunneling
International Nuclear Information System (INIS)
Beams, Ryan; Bharadwaj, Palash; Novotny, Lukas
2014-01-01
We use low-energy electron tunneling to excite electroluminescence in single layer graphene. Electrons are injected locally using a scanning tunneling microscope and the luminescence is analyzed using a wide-angle optical imaging system. The luminescence can be switched on and off by inverting the tip–sample bias voltage. The observed luminescence is explained in terms of a hot luminescence mechanism. (paper)
|
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|
https://www.speedsolving.com/threads/javascript-port-of-visualcube.72356/
|
# Javascript port of visualcube
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
Hey guys. Just thought I'd post this here in case anyone was interested. I'm sure most of you have heard of visualcube. I've put a little work into porting it to typescript/javascript to allow rendering images right in your page without requesting it from the old .php file. You can find my progress here https://github.com/tdecker91/visualcube
I know there are other great javascript cube visualization libraries out there, like TwistySim and RoofPig. Other libraries that have a larger variety of supported puzzles etc... But visualcube was always my favorite. It looks great. Plus sometimes you only need to generate an image and don't need a 3d interactive puzzle.
The code is pretty much spaghetti, but it seems to function almost just like the original. I left out a few minor features. Also the api is changed a bit. Calling it from javascript is completely different from the old URL parameter api.
I hope to take what I learned from doing this and build a more generic version that can render any WCA puzzle. And make the code cleaner while i'm at it.
Anyway, enjoy! I hope someone finds it useful.
Let me know if you have any suggestions or find any issues with it. Hopefully the documentation is clear.
Edits:
Algorithm parsing has been improved. It should support any valid WCA scramble for NxN cubes. The alg can be applied to any size cube
For example, the following will scramble a 5x5 cube. The same pattern can be used for larger cubes.
JavaScript:
cubePNG(element, {
cubeSize: 5,
algorithm: 'R U Uw2 Bw\' Dw L\' F\' Lw\' Dw Lw\' B Lw2 Bw B2 U2 L\' Fw Rw D\' Rw\' Bw D\' Rw2 L2 B L2 Bw L B\' R\' F\' R\' B\' Dw2 Lw2 D2 Dw\' B Lw L\' R\' Fw Uw2 R2 Bw\' Lw\' B R L\' Dw2 F D2 Bw\' U\' Uw F\' B R\' D2 Bw2'
});
I've updated the API so you can pass in the old style URL for the parameters so you don't have to rebuild any of your image configs to use this.
Example
JavaScript:
cubePNG(element, "visualcube.php?size=150&pzl=3&stage=f2l&case=U(RU'R')&fmt=png&sch=ygrwbo")
I've added support for the old "fd" parameter. This allows user to define color of sticker by color scheme. "Transparent" stickers work now as well. If the sticker color is "transparent" then it won't even be rendered.
Not much of a change, but these are just steps making it more backwards compatible with the original version.
Last edited:
#### AndyK
##### Premium Member
Joined
Apr 5, 2009
Messages
172
This is fantastic. Thank you!
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
This is fantastic. Thank you!
Thanks!
Also one improvement from the original version that I just added. It supports standard WCA algorithms passed in. And the algorithms can be applied to any size cube.
Example:
JavaScript:
cubePNG(element, {
cubeSize: 5,
algorithm: 'R U Uw2 Bw\' Dw L\' F\' Lw\' Dw Lw\' B Lw2 Bw B2 U2 L\' Fw Rw D\' Rw\' Bw D\' Rw2 L2 B L2 Bw L B\' R\' F\' R\' B\' Dw2 Lw2 D2 Dw\' B Lw L\' R\' Fw Uw2 R2 Bw\' Lw\' B R L\' Dw2 F D2 Bw\' U\' Uw F\' B R\' D2 Bw2'
});
Results:
#### Attachments
• scramble.png
29 KB · Views: 0
Last edited:
Reactions: pjk
#### AndyK
##### Premium Member
Joined
Apr 5, 2009
Messages
172
More great stuff! Certainly appreciate your work on this
I wonder if more people would utilize this if you came up with a quick program which would translate standard VisualCube notation like this:
• visualcube.php?size=150&pzl=3&stage=f2l&case=U(RU'R')&fmt=png&sch=ygrwbo
• visualcube.php?size=150&pzl=3&stage=f2l&case=y'U'(R'UR)&fmt=png&sch=yrbwog
into your Javascript notation.
Perhaps even better, what about a program that takes plain text inputs for each VisualCube input and spits out the Javascript VisualCube notation (and even the standard VisualCube notation)
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
More great stuff! Certainly appreciate your work on this
I wonder if more people would utilize this if you came up with a quick program which would translate standard VisualCube notation like this:
• visualcube.php?size=150&pzl=3&stage=f2l&case=U(RU'R')&fmt=png&sch=ygrwbo
• visualcube.php?size=150&pzl=3&stage=f2l&case=y'U'(R'UR)&fmt=png&sch=yrbwog
into your Javascript notation.
Perhaps even better, what about a program that takes plain text inputs for each VisualCube input and spits out the Javascript VisualCube notation (and even the standard VisualCube notation)
Great idea! Yeah I had thought of this and have already implemented this idea for the arrows parameter. Because passing in a bunch of arrow definitions was a bit cumbersome compared to the old way. I just need to do this for all the parameter types. Or for example, when calling cubePNG if the options you pass in is a string parameter like this
Code:
cubePNG(element, 'size=150&pzl=3&stage=f2l&case=y'U'(R'UR)&fmt=png&sch=yrbwog')
It could just assume the parameters are to be parsed the old way. That's very doable. I'll see what I can come up with.
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
Great news! I was able to do what I was suggesting no problem.
The following examples you provided renders the following images
Code:
cubePNG(element, "visualcube.php?size=150&pzl=3&stage=f2l&case=U(RU'R')&fmt=png&sch=ygrwbo")
cubePNG(element, "visualcube.php?size=150&pzl=3&stage=f2l&case=y'U'(R'UR)&fmt=png&sch=yrbwog")
There's a few caveats. The "fmt" parameter is ignored, because fmt is determined by calling either cubePNG or cubeSVG. The "fd" and "ac" parameters are also ignored because I haven't programmed the functionality for those yet.
But other than that I think everything works as expected.You can just provide the old URL used for the php script.
If you want to use this functionality make sure you have version 1.0.5 installed via npm. Or just pull the recent changes in the repository.
Reactions: pjk
#### AndyK
##### Premium Member
Joined
Apr 5, 2009
Messages
172
Code:
cubePNG(element, "visualcube.php?size=150&pzl=3&stage=f2l&case=U(RU'R')&fmt=png&sch=ygrwbo")
cubePNG(element, "visualcube.php?size=150&pzl=3&stage=f2l&case=y'U'(R'UR)&fmt=png&sch=yrbwog")
I love it! This is great stuff!
#### bdalyanci
##### Member
Joined
Feb 8, 2019
Messages
2
Brilliant. Thanks. I'll make this exercise for my coding students.
#### Filipe Teixeira
##### Member
Joined
Aug 12, 2013
Messages
1,978
Location
Brazil
YouTube
Visit Channel
Apparently rotations (x, x', x2, y, y', y2, z, z', z2) are not supported.
I put this on my code for rotations to work (filter alg before rendering)
JavaScript:
function algFilter(alg) {
const dictionary = {
"y": "U D' E'",
"y'": "U' D E",
"y2": "U2 D2 E2",
"x": "R M' L'",
"x'": "R' M L",
"x2": "R2 M2 L2",
"z": "F B' S",
"z'": "F' B S'",
"z2": "F2 B2 S2",
};
let final_alg = [];
alg.split(/(\s+)/).forEach(move => {
if (move in dictionary) {
final_alg.push(dictionary[move]);
} else {
final_alg.push(move);
}
});
return final_alg.join(' ');
}
Last edited:
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
You're right. x y z rotation should be supported. Looks like a bug I introduced. I fixed it and pushed new version of the package. 1.0.7
Apparently rotations (x, x', x2, y, y', y2, z, z', z2) are not supported.
I put this on my code for rotations to work (filter alg before rendering)
JavaScript:
function algFilter(alg) {
const dictionary = {
"y": "U D' E'",
"y'": "U' D E",
"y2": "U2 D2 E2",
"x": "R M' L'",
"x'": "R' M L",
"x2": "R2 M2 L2",
"z": "F B' S",
"z'": "F' B S'",
"z2": "F2 B2 S2",
};
let final_alg = [];
alg.split(/(\s+)/).forEach(move =>
if (move in dictionary) {
final_alg.push(dictionary[move]);
} else {
final_alg.push(move);
}
});
return final_alg.join(' ');
}
#### Eelpi
##### Member
Joined
Jun 26, 2019
Messages
2
Great work! By the way, is there a way to disable console.log() messages?
#### SolvingRubik
##### Member
Joined
Jan 24, 2019
Messages
12
Great work! By the way, is there a way to disable console.log() messages?
Gah! yes. of course I would accidentally leave that in there. not sure if npm lets you override an existing version. So I had to make due with updating the package version to 1.0.8
Thanks for the feeback!
#### Eelpi
##### Member
Joined
Jun 26, 2019
Messages
2
Thanks for going through the trouble of updating it!
I'm making an algorithm trainer and this was a godsend as I wanted to keep it pure js
|
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|
https://bookdown.org/egarpor/SSS2-UC3M/simplin-assumps.html
|
## 2.4 Assumptions of the model
Why do we need assumptions? To make inference on the model parameters. In other words, to infer properties about the unknown population coefficients $$\beta_0$$ and $$\beta_1$$ from the sample $$(X_1,Y_1),\ldots,(X_n,Y_n)$$.
The assumptions of the linear model are:
1. Linearity: $$\mathbb{E}[Y|X=x]=\beta_0+\beta_1x$$.
2. Homoscedasticity: $$\mathbb{V}\text{ar}[\varepsilon_i]=\sigma^2$$, with $$\sigma^2$$ constant for $$i=1,\ldots,n$$.
3. Normality: $$\varepsilon_i\sim\mathcal{N}(0,\sigma^2)$$ for $$i=1,\ldots,n$$.
4. Independence of the errors: $$\varepsilon_1,\ldots,\varepsilon_n$$ are independent (or uncorrelated, $$\mathbb{E}[\varepsilon_i\varepsilon_j]=0$$, $$i\neq j$$, since they are assumed to be normal).
A good one-line summary of the linear model is (independence is assumed) \begin{align*} Y|X=x\sim \mathcal{N}(\beta_0+\beta_1x,\sigma^2) \end{align*}
Recall:
• Nothing is said about the distribution of X. Indeed, X could be deterministic (called fixed design) or random (random design).
• The linear model assumes that Y is continuous due to the normality of the errors. However, X can be discrete!
Figures 2.18 and 2.19 represent situations where the assumptions of the model are respected and violated, respectively. For the moment, we will focus on building the intuition for checking the assumptions visually. In Chapter 3 we will see more sophisticated methods for checking the assumptions. We will see also what are the possible fixes to the failure of assumptions.
The dataset assumptions.RData (download) contains the variables x1, …, x9 and y1, …, y9. For each regression y1 ~ x1, …, y9 ~ x9:
• Check whether the assumptions of the linear model are being satisfied (make a scatterplot with a regression line).
|
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|
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