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Title: Exotic pairing symmetry of interacting Dirac fermions on a $π$ flux lattice,
Abstract: The pairing symmetry of interacting Dirac fermions on the $\pi$-flux lattice
is studied with the determinant quantum Monte Carlo and numerical linked
cluster expansion methods. The extended $s^*$- (i.e. extended $s$-) and d-wave
pairing symmetries, which are distinct in the conventional square lattice, are
degenerate under the Landau gauge. We demonstrate that the dominant pairing
channel at strong interactions is an exotic $ds^*$-wave phase consisting of
alternating stripes of $s^*$- and d-wave phases. A complementary mean-field
analysis shows that while the $s^*$- and d-wave symmetries individually have
nodes in the energy spectrum, the $ds^*$ channel is fully gapped. The results
represent a new realization of pairing in Dirac systems, connected to the
problem of chiral d-wave pairing on the honeycomb lattice, which might be more
readily accessed by cold-atom experiments. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Learning Causal Structures Using Regression Invariance,
Abstract: We study causal inference in a multi-environment setting, in which the
functional relations for producing the variables from their direct causes
remain the same across environments, while the distribution of exogenous noises
may vary. We introduce the idea of using the invariance of the functional
relations of the variables to their causes across a set of environments. We
define a notion of completeness for a causal inference algorithm in this
setting and prove the existence of such algorithm by proposing the baseline
algorithm. Additionally, we present an alternate algorithm that has
significantly improved computational and sample complexity compared to the
baseline algorithm. The experiment results show that the proposed algorithm
outperforms the other existing algorithms. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Linear Exponential Comonads without Symmetry,
Abstract: The notion of linear exponential comonads on symmetric monoidal categories
has been used for modelling the exponential modality of linear logic. In this
paper we introduce linear exponential comonads on general (possibly
non-symmetric) monoidal categories, and show some basic results on them. | [
1,
0,
1,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Multi-speaker Recognition in Cocktail Party Problem,
Abstract: This paper proposes an original statistical decision theory to accomplish a
multi-speaker recognition task in cocktail party problem. This theory relies on
an assumption that the varied frequencies of speakers obey Gaussian
distribution and the relationship of their voiceprints can be represented by
Euclidean distance vectors. This paper uses Mel-Frequency Cepstral Coefficients
to extract the feature of a voice in judging whether a speaker is included in a
multi-speaker environment and distinguish who the speaker should be. Finally, a
thirteen-dimension constellation drawing is established by mapping from
Manhattan distances of speakers in order to take a thorough consideration about
gross influential factors. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: COLOSSUS: A python toolkit for cosmology, large-scale structure, and dark matter halos,
Abstract: This paper introduces Colossus, a public, open-source python package for
calculations related to cosmology, the large-scale structure (LSS) of matter in
the universe, and the properties of dark matter halos. The code is designed to
be fast and easy to use, with a coherent, well-documented user interface. The
cosmology module implements Friedman-Lemaitre-Robertson-Walker cosmologies
including curvature, relativistic species, and different dark energy equations
of state, and provides fast computations of the linear matter power spectrum,
variance, and correlation function. The LSS module is concerned with the
properties of peaks in Gaussian random fields and halos in a statistical sense,
including their peak height, peak curvature, halo bias, and mass function. The
halo module deals with spherical overdensity radii and masses, density
profiles, concentration, and the splashback radius. To facilitate the rapid
exploration of these quantities, Colossus implements more than 40 different
fitting functions from the literature. I discuss the core routines in detail,
with particular emphasis on their accuracy. Colossus is available at
bitbucket.org/bdiemer/colossus. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Computer Science"
] |
Title: Hydra: An Accelerator for Real-Time Edge-Aware Permeability Filtering in 65nm CMOS,
Abstract: Many modern video processing pipelines rely on edge-aware (EA) filtering
methods. However, recent high-quality methods are challenging to run in
real-time on embedded hardware due to their computational load. To this end, we
propose an area-efficient and real-time capable hardware implementation of a
high quality EA method. In particular, we focus on the recently proposed
permeability filter (PF) that delivers promising quality and performance in the
domains of HDR tone mapping, disparity and optical flow estimation. We present
an efficient hardware accelerator that implements a tiled variant of the PF
with low on-chip memory requirements and a significantly reduced external
memory bandwidth (6.4x w.r.t. the non-tiled PF). The design has been taped out
in 65 nm CMOS technology, is able to filter 720p grayscale video at 24.8 Hz and
achieves a high compute density of 6.7 GFLOPS/mm2 (12x higher than embedded
GPUs when scaled to the same technology node). The low area and bandwidth
requirements make the accelerator highly suitable for integration into SoCs
where silicon area budget is constrained and external memory is typically a
heavily contended resource. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Physics"
] |
Title: A Contextual Bandit Approach for Stream-Based Active Learning,
Abstract: Contextual bandit algorithms -- a class of multi-armed bandit algorithms that
exploit the contextual information -- have been shown to be effective in
solving sequential decision making problems under uncertainty. A common
assumption adopted in the literature is that the realized (ground truth) reward
by taking the selected action is observed by the learner at no cost, which,
however, is not realistic in many practical scenarios. When observing the
ground truth reward is costly, a key challenge for the learner is how to
judiciously acquire the ground truth by assessing the benefits and costs in
order to balance learning efficiency and learning cost. From the information
theoretic perspective, a perhaps even more interesting question is how much
efficiency might be lost due to this cost. In this paper, we design a novel
contextual bandit-based learning algorithm and endow it with the active
learning capability. The key feature of our algorithm is that in addition to
sending a query to an annotator for the ground truth, prior information about
the ground truth learned by the learner is sent together, thereby reducing the
query cost. We prove that by carefully choosing the algorithm parameters, the
learning regret of the proposed algorithm achieves the same order as that of
conventional contextual bandit algorithms in cost-free scenarios, implying
that, surprisingly, cost due to acquiring the ground truth does not increase
the learning regret in the long-run. Our analysis shows that prior information
about the ground truth plays a critical role in improving the system
performance in scenarios where active learning is necessary. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Low Auto-correlation Binary Sequences explored using Warning Propagation,
Abstract: The search of binary sequences with low auto-correlations (LABS) is a
discrete combinatorial optimization problem contained in the NP-hard
computational complexity class. We study this problem using Warning Propagation
(WP) , a message passing algorithm, and compare the performance of the
algorithm in the original problem and in two different disordered versions. We
show that in all the cases Warning Propagation converges to low energy minima
of the solution space. Our results highlight the importance of the local
structure of the interaction graph of the variables for the convergence time of
the algorithm and for the quality of the solutions obtained by WP. While in
general the algorithm does not provide the optimal solutions in large systems
it does provide, in polynomial time, solutions that are energetically similar
to the optimal ones. Moreover, we designed hybrid models that interpolate
between the standard LABS problem and the disordered versions of it, and
exploit them to improved the convergence time of WP and the quality of the
solutions. | [
0,
1,
0,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Estimation of the marginal expected shortfall under asymptotic independence,
Abstract: We study the asymptotic behavior of the marginal expected shortfall when the
two random variables are asymptotic independent but positive associated, which
is modeled by the so-called tail dependent coefficient. We construct an
estimator of the marginal expected shortfall which is shown to be
asymptotically normal. The finite sample performance of the estimator is
investigated in a small simulation study. The method is also applied to
estimate the expected amount of rainfall at a weather station given that there
is a once every 100 years rainfall at another weather station nearby. | [
0,
0,
1,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: Downgrade Attack on TrustZone,
Abstract: Security-critical tasks require proper isolation from untrusted software.
Chip manufacturers design and include trusted execution environments (TEEs) in
their processors to secure these tasks. The integrity and security of the
software in the trusted environment depend on the verification process of the
system.
We find a form of attack that can be performed on the current implementations
of the widely deployed ARM TrustZone technology. The attack exploits the fact
that the trustlet (TA) or TrustZone OS loading verification procedure may use
the same verification key and may lack proper rollback prevention across
versions. If an exploit works on an out-of-date version, but the vulnerability
is patched on the latest version, an attacker can still use the same exploit to
compromise the latest system by downgrading the software to an older and
exploitable version.
We did experiments on popular devices on the market including those from
Google, Samsung and Huawei, and found that all of them have the risk of being
attacked. Also, we show a real-world example to exploit Qualcomm's QSEE.
In addition, in order to find out which device images share the same
verification key, pattern matching schemes for different vendors are analyzed
and summarized. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Robust Inference under the Beta Regression Model with Application to Health Care Studies,
Abstract: Data on rates, percentages or proportions arise frequently in many different
applied disciplines like medical biology, health care, psychology and several
others. In this paper, we develop a robust inference procedure for the beta
regression model which is used to describe such response variables taking
values in $(0, 1)$ through some related explanatory variables. In relation to
the beta regression model, the issue of robustness has been largely ignored in
the literature so far. The existing maximum likelihood based inference has
serious lack of robustness against outliers in data and generate drastically
different (erroneous) inference in presence of data contamination. Here, we
develop the robust minimum density power divergence estimator and a class of
robust Wald-type tests for the beta regression model along with several
applications. We derive their asymptotic properties and describe their
robustness theoretically through the influence function analyses. Finite sample
performances of the proposed estimators and tests are examined through suitable
simulation studies and real data applications in the context of health care and
psychology. Although we primarily focus on the beta regression models with a
fixed dispersion parameter, some indications are also provided for extension to
the variable dispersion beta regression models with an application. | [
0,
0,
0,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: PageRank in Undirected Random Graphs,
Abstract: PageRank has numerous applications in information retrieval, reputation
systems, machine learning, and graph partitioning. In this paper, we study
PageRank in undirected random graphs with an expansion property. The Chung-Lu
random graph is an example of such a graph. We show that in the limit, as the
size of the graph goes to infinity, PageR- ank can be approximated by a mixture
of the restart distribution and the vertex degree distribution. We also extend
the result to Stochastic Block Model (SBM) graphs, where we show that there is
a correction term that depends on the community partitioning. | [
0,
0,
1,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: On the Genus of the Moonshine Module,
Abstract: We provide a novel and simple description of Schellekens' seventy-one affine
Kac-Moody structures of self-dual vertex operator algebras of central charge 24
by utilizing cyclic subgroups of the glue codes of the Niemeier lattices with
roots. We also discuss a possible uniform construction procedure of the
self-dual vertex operator algebras of central charge 24 starting from the Leech
lattice. This also allows us to consider the uniqueness question for all
non-trivial affine Kac-Moody structures. We finally discuss our description
from a Lorentzian viewpoint. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Physics"
] |
Title: A Deep Learning-based Reconstruction of Cosmic Ray-induced Air Showers,
Abstract: We describe a method of reconstructing air showers induced by cosmic rays
using deep learning techniques. We simulate an observatory consisting of
ground-based particle detectors with fixed locations on a regular grid. The
detector's responses to traversing shower particles are signal amplitudes as a
function of time, which provide information on transverse and longitudinal
shower properties. In order to take advantage of convolutional network
techniques specialized in local pattern recognition, we convert all information
to the image-like grid of the detectors. In this way, multiple features, such
as arrival times of the first particles and optimized characterizations of time
traces, are processed by the network. The reconstruction quality of the cosmic
ray arrival direction turns out to be competitive with an analytic
reconstruction algorithm. The reconstructed shower direction, energy and shower
depth show the expected improvement in resolution for higher cosmic ray energy. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Computer Science"
] |
Title: Foresight: Recommending Visual Insights,
Abstract: Current tools for exploratory data analysis (EDA) require users to manually
select data attributes, statistical computations and visual encodings. This can
be daunting for large-scale, complex data. We introduce Foresight, a system
that helps the user rapidly discover visual insights from large
high-dimensional datasets. Formally, an "insight" is a strong manifestation of
a statistical property of the data, e.g., high correlation between two
attributes, high skewness or concentration about the mean of a single
attribute, a strong clustering of values, and so on. For each insight type,
Foresight initially presents visualizations of the top k instances in the data,
based on an appropriate ranking metric. The user can then look at "nearby"
insights by issuing "insight queries" containing constraints on insight
strengths and data attributes. Thus the user can directly explore the space of
insights, rather than the space of data dimensions and visual encodings as in
other visual recommender systems. Foresight also provides "global" views of
insight space to help orient the user and ensure a thorough exploration
process. Furthermore, Foresight facilitates interactive exploration of large
datasets through fast, approximate sketching. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Hierarchy of exchange interactions in the triangular-lattice spin-liquid YbMgGaO$_{4}$,
Abstract: The spin-1/2 triangular lattice antiferromagnet YbMgGaO$_{4}$ has attracted
recent attention as a quantum spin-liquid candidate with the possible presence
of off-diagonal anisotropic exchange interactions induced by spin-orbit
coupling. Whether a quantum spin-liquid is stabilized or not depends on the
interplay of various exchange interactions with chemical disorder that is
inherent to the layered structure of the compound. We combine time-domain
terahertz spectroscopy and inelastic neutron scattering measurements in the
field polarized state of YbMgGaO$_{4}$ to obtain better microscopic insights on
its exchange interactions. Terahertz spectroscopy in this fashion functions as
high-field electron spin resonance and probes the spin-wave excitations at the
Brillouin zone center, ideally complementing neutron scattering. A global
spin-wave fit to all our spectroscopic data at fields over 4T, informed by the
analysis of the terahertz spectroscopy linewidths, yields stringent constraints
on $g$-factors and exchange interactions. Our results paint YbMgGaO$_{4}$ as an
easy-plane XXZ antiferromagnet with the combined and necessary presence of
sub-leading next-nearest neighbor and weak anisotropic off-diagonal
nearest-neighbor interactions. Moreover, the obtained $g$-factors are
substantially different from previous reports. This works establishes the
hierarchy of exchange interactions in YbMgGaO$_{4}$ from high-field data alone
and thus strongly constrains possible mechanisms responsible for the observed
spin-liquid phenomenology. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: A Potential Recoiling Supermassive Black Hole CXO J101527.2+625911,
Abstract: We have carried out a systematic search for recoiling supermassive black
holes (rSMBH) using the Chandra Source and SDSS Cross Matched Catalog. From the
survey, we have detected a potential rSMBH, 'CXO J101527.2+625911' at z=0.3504.
The CXO J101527.2+625911 has a spatially offset (1.26$\pm$0.05 kpc) active SMBH
and kinematically offset broad emission lines (175$\pm$25 km s$^{\rm -1}$
relative to systemic velocity). The observed spatial and velocity offsets
suggest this galaxy could be a rSMBH, but we also have considered a possibility
of dual SMBH scenario. The column density towards the galaxy center was found
to be Compton thin, but no X-ray source was detected. The non-detection of the
X-ray source in the nucleus suggests either there is no obscured actively
accreting SMBH, or there exists an SMBH but has a low accretion rate (i.e.
low-luminosity AGN (LLAGN)). The possibility of the LLAGN was investigated and
found to be unlikely based on the H$\alpha$ luminosity, radio power, and
kinematic arguments. This, along with the null detection of X-ray source in the
nucleus supports our hypothesis that the CXO J101527.2+625911 is a rSMBH. Our
GALFIT analysis shows the host galaxy to be a bulge-dominated elliptical. The
weak morphological disturbance and small spatial and velocity offsets suggest
that CXO J101527.2+625911 could be in the final stage of merging process and
about to turn into a normal elliptical galaxy. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: WLAN Performance Analysis Ibrahim Group of industries Faisalabad Pakistan,
Abstract: Now a days several organizations are moving their LAN foundation towards
remote LAN frame work. The purpose for this is extremely straight forward
multinational organizations needs their clients surprise about their office
surroundings and they additionally need to make wire free environment in their
workplaces. Much IT equipment moved on Wireless for instance all in one Pc
portable workstations Wireless IP telephones. Another thing is that step by
step WLAN innovation moving towards extraordinary effectiveness. In this
exploration work Wireless LAN innovation running in Ibrahim Group gathering of
commercial enterprises Faisalabad has been investigated in term of their
equipment, Wireless signal quality, data transmission, auto channel moving, and
security in WLAN system. This examination work required physical proving
ground, some WLAN system analyzer (TamoSof throughput) software, hardware point
of interest, security testing programming. The investigation displayed in this
examination has fill two key needs. One determination is to accept this kind of
system interconnection could be broke down utilizing the exploratory models of
the two system bits (wired and remote pieces. Second key factor is to determine
the security issue in WLAN. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Global linear convergent algorithm to compute the minimum volume enclosing ellipsoid,
Abstract: The minimum volume enclosing ellipsoid (MVEE) problem is an optimization
problem in the basis of many practical problems. This paper describes some new
properties of this model and proposes a first-order oracle algorithm, the
Adjusted Coordinate Descent (ACD) algorithm, to address the MVEE problem. The
ACD algorithm is globally linear convergent and has an overwhelming advantage
over the other algorithms in cases where the dimension of the data is large.
Moreover, as a byproduct of the convergence property of the ACD algorithm, we
prove the global linear convergence of the Frank-Wolfe type algorithm
(illustrated by the case of Wolfe-Atwood's algorithm), which supports the
conjecture of Todd. Furthermore, we provide a new interpretation for the means
of choosing the coordinate axis of the Frank-Wolfe type algorithm from the
perspective of the smoothness of the coordinate axis, i.e., the algorithm
chooses the coordinate axis with the worst smoothness at each iteration. This
finding connects the first-order oracle algorithm and the linear optimization
oracle algorithm on the MVEE problem. The numerical tests support our
theoretical results. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Computer Science"
] |
Title: Contrasting information theoretic decompositions of modulatory and arithmetic interactions in neural information processing systems,
Abstract: Biological and artificial neural systems are composed of many local
processors, and their capabilities depend upon the transfer function that
relates each local processor's outputs to its inputs. This paper uses a recent
advance in the foundations of information theory to study the properties of
local processors that use contextual input to amplify or attenuate transmission
of information about their driving inputs. This advance enables the information
transmitted by processors with two distinct inputs to be decomposed into those
components unique to each input, that shared between the two inputs, and that
which depends on both though it is in neither, i.e. synergy. The decompositions
that we report here show that contextual modulation has information processing
properties that contrast with those of all four simple arithmetic operators,
that it can take various forms, and that the form used in our previous studies
of artificial neural nets composed of local processors with both driving and
contextual inputs is particularly well-suited to provide the distinctive
capabilities of contextual modulation under a wide range of conditions. We
argue that the decompositions reported here could be compared with those
obtained from empirical neurobiological and psychophysical data under
conditions thought to reflect contextual modulation. That would then shed new
light on the underlying processes involved. Finally, we suggest that such
decompositions could aid the design of context-sensitive machine learning
algorithms. | [
0,
0,
0,
1,
1,
0
] | [
"Computer Science",
"Quantitative Biology",
"Mathematics"
] |
Title: Recommendations for Marketing Campaigns in Telecommunication Business based on the footprint analysis,
Abstract: A major investment made by a telecom operator goes into the infrastructure
and its maintenance, while business revenues are proportional to how big and
good the customer base is. We present a data-driven analytic strategy based on
combinatorial optimization and analysis of historical data. The data cover
historical mobility of the users in one region of Sweden during a week.
Applying the proposed method to the case study, we have identified the optimal
proportion of geo-demographic segments in the customer base, developed a
functionality to assess the potential of a planned marketing campaign, and
explored the problem of an optimal number and types of the geo-demographic
segments to target through marketing campaigns. With the help of fuzzy logic,
the conclusions of data analysis are automatically translated into
comprehensible recommendations in a natural language. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics",
"Quantitative Finance"
] |
Title: Enhancing The Reliability of Out-of-distribution Image Detection in Neural Networks,
Abstract: We consider the problem of detecting out-of-distribution images in neural
networks. We propose ODIN, a simple and effective method that does not require
any change to a pre-trained neural network. Our method is based on the
observation that using temperature scaling and adding small perturbations to
the input can separate the softmax score distributions between in- and
out-of-distribution images, allowing for more effective detection. We show in a
series of experiments that ODIN is compatible with diverse network
architectures and datasets. It consistently outperforms the baseline approach
by a large margin, establishing a new state-of-the-art performance on this
task. For example, ODIN reduces the false positive rate from the baseline 34.7%
to 4.3% on the DenseNet (applied to CIFAR-10) when the true positive rate is
95%. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Nef partitions for codimension 2 weighted complete intersections,
Abstract: We prove that a smooth well formed Fano weighted complete intersection of
codimension 2 has a nef partition. We discuss applications of this fact to
Mirror Symmetry. In particular we list all nef partitions for smooth well
formed Fano weighted complete intersections of dimensions 4 and 5 and present
weak Landau--Ginzburg models for them. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Integrating sentiment and social structure to determine preference alignments: The Irish Marriage Referendum,
Abstract: We examine the relationship between social structure and sentiment through
the analysis of a large collection of tweets about the Irish Marriage
Referendum of 2015. We obtain the sentiment of every tweet with the hashtags
#marref and #marriageref that was posted in the days leading to the referendum,
and construct networks to aggregate sentiment and use it to study the
interactions among users. Our results show that the sentiment of mention tweets
posted by users is correlated with the sentiment of received mentions, and
there are significantly more connections between users with similar sentiment
scores than among users with opposite scores in the mention and follower
networks. We combine the community structure of the two networks with the
activity level of the users and sentiment scores to find groups of users who
support voting `yes' or `no' in the referendum. There were numerous
conversations between users on opposing sides of the debate in the absence of
follower connections, which suggests that there were efforts by some users to
establish dialogue and debate across ideological divisions. Our analysis shows
that social structure can be integrated successfully with sentiment to analyse
and understand the disposition of social media users. These results have
potential applications in the integration of data and meta-data to study
opinion dynamics, public opinion modelling, and polling. | [
1,
1,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Tailoring symmetric metallic and magnetic edge states of nanoribbon in semiconductive monolayer PtS2,
Abstract: Fabrication of atomic scale of metallic wire remains challenging. In present
work, a nanoribbon with two parallel symmetric metallic and magnetic edges was
designed from semiconductive monolayer PtS2 by employing first-principles
calculations based on density functional theory. Edge energy, bonding charge
density, band structure and simulated STM of possible edges states of PtS2 were
systematically studied. It was found that Pt-terminated edge nanoribbons were
the relatively stable metallic and magnetic edge tailored from a noble
transition metal dichalcogenides PtS2. The nanoribbon with two atomic metallic
wires may have promising application as nano power transmission lines, which at
least two lines are needed. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Materials Science"
] |
Title: Restriction of representations of metaplectic $GL_{2}(F)$ to tori,
Abstract: Let $F$ be a non-Archimedean local field. We study the restriction of an
irreducible admissible genuine representations of the two fold metaplectic
cover $\widetilde{GL}_{2}(F)$ of $GL_{2}(F)$ to the inverse image in
$\widetilde{GL}_{2}(F)$ of a maximal torus in $GL_{2}(F)$. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: EmbedJoin: Efficient Edit Similarity Joins via Embeddings,
Abstract: We study the problem of edit similarity joins, where given a set of strings
and a threshold value $K$, we want to output all pairs of strings whose edit
distances are at most $K$. Edit similarity join is a fundamental problem in
data cleaning/integration, bioinformatics, collaborative filtering and natural
language processing, and has been identified as a primitive operator for
database systems. This problem has been studied extensively in the literature.
However, we have observed that all the existing algorithms fall short on long
strings and large distance thresholds.
In this paper we propose an algorithm named EmbedJoin which scales very well
with string length and distance threshold. Our algorithm is built on the recent
advance of metric embeddings for edit distance, and is very different from all
of the previous approaches. We demonstrate via an extensive set of experiments
that EmbedJoin significantly outperforms the previous best algorithms on long
strings and large distance thresholds. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Construction of curve pairs and their applications,
Abstract: In this study, we introduce a new approach to curve pairs by using integral
curves. We consider the direction curve and donor curve to study curve couples
such as involute-evolute curves, Mannheim partner curves and Bertrand partner
curves. We obtain new methods to construct partner curves of a unit speed curve
and give some applications related to helices, slant helices and plane curves. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Simulation studies for dielectric wakefield programme at CLARA facility,
Abstract: Short, high charge electron bunches can drive high magnitude electric fields
in dielectric lined structures. The interaction of the electron bunch with this
field has several applications including high gradient dielectric wakefield
acceleration (DWA) and passive beam manipulation. The simulations presented
provide a prelude to the commencement of an experimental DWA programme at the
CLARA accelerator at Daresbury Laboratory. The key goals of this program are:
tunable generation of THz radiation, understanding of the impact of transverse
wakes, and design of a dechirper for the CLARA FEL. Computations of
longitudinal and transverse phase space evolution were made with Impact-T and
VSim to support both of these goals. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: The Frobenius morphism in invariant theory,
Abstract: Let $R$ be the homogeneous coordinate ring of the Grassmannian
$\mathbb{G}=\operatorname{Gr}(2,n)$ defined over an algebraically closed field
of characteristic $p>0$. In this paper we give a completely characteristic free
description of the decomposition of $R$, considered as a graded $R^p$-module,
into indecomposables ("Frobenius summands"). As a corollary we obtain a similar
decomposition for the Frobenius pushforward of the structure sheaf of
$\mathbb{G}$ and we obtain in particular that this pushforward is almost never
a tilting bundle. On the other hand we show that $R$ provides a "noncommutative
resolution" for $R^p$ when $p\ge n-2$, generalizing a result known to be true
for toric varieties.
In both the invariant theory and the geometric setting we observe that if the
characteristic is not too small the Frobenius summands do not depend on the
characteristic in a suitable sense. In the geometric setting this is an
explicit version of a general result by Bezrukavnikov and Mirković on
Frobenius decompositions for partial flag varieities. We are hopeful that it is
an instance of a more general "$p$-uniformity" principle. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: A General Probabilistic Approach for Quantitative Assessment of LES Combustion Models,
Abstract: The Wasserstein metric is introduced as a probabilistic method to enable
quantitative evaluations of LES combustion models. The Wasserstein metric can
directly be evaluated from scatter data or statistical results using
probabilistic reconstruction against experimental data. The method is derived
and generalized for turbulent reacting flows, and applied to validation tests
involving the Sydney piloted jet flame. It is shown that the Wasserstein metric
is an effective validation tool that extends to multiple scalar quantities,
providing an objective and quantitative evaluation of model deficiencies and
boundary conditions on the simulation accuracy. Several test cases are
considered, beginning with a comparison of mixture-fraction results, and the
subsequent extension to reactive scalars, including temperature and species
mass fractions of \ce{CO} and \ce{CO2}. To demonstrate the versatility of the
proposed method in application to multiple datasets, the Wasserstein metric is
applied to a series of different simulations that were contributed to the
TNF-workshop. Analysis of the results allowed to identify competing
contributions to model deviations, arising from uncertainties in the boundary
conditions and model deficiencies. These applications demonstrate that the
Wasserstein metric constitutes an easily applicable mathematical tool that
reduce multiscalar combustion data and large datasets into a scalar-valued
quantitative measure. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Mathematics",
"Statistics"
] |
Title: A glass-box interactive machine learning approach for solving NP-hard problems with the human-in-the-loop,
Abstract: The goal of Machine Learning to automatically learn from data, extract
knowledge and to make decisions without any human intervention. Such automatic
(aML) approaches show impressive success. Recent results even demonstrate
intriguingly that deep learning applied for automatic classification of skin
lesions is on par with the performance of dermatologists, yet outperforms the
average. As human perception is inherently limited, such approaches can
discover patterns, e.g. that two objects are similar, in arbitrarily
high-dimensional spaces what no human is able to do. Humans can deal only with
limited amounts of data, whilst big data is beneficial for aML; however, in
health informatics, we are often confronted with a small number of data sets,
where aML suffer of insufficient training samples and many problems are
computationally hard. Here, interactive machine learning (iML) may be of help,
where a human-in-the-loop contributes to reduce the complexity of NP-hard
problems. A further motivation for iML is that standard black-box approaches
lack transparency, hence do not foster trust and acceptance of ML among
end-users. Rising legal and privacy aspects, e.g. with the new European General
Data Protection Regulations, make black-box approaches difficult to use,
because they often are not able to explain why a decision has been made. In
this paper, we present some experiments to demonstrate the effectiveness of the
human-in-the-loop approach, particularly in opening the black-box to a
glass-box and thus enabling a human directly to interact with an learning
algorithm. We selected the Ant Colony Optimization framework, and applied it on
the Traveling Salesman Problem, which is a good example, due to its relevance
for health informatics, e.g. for the study of protein folding. From studies of
how humans extract so much from so little data, fundamental ML-research also
may benefit. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Bayesian Coreset Construction via Greedy Iterative Geodesic Ascent,
Abstract: Coherent uncertainty quantification is a key strength of Bayesian methods.
But modern algorithms for approximate Bayesian posterior inference often
sacrifice accurate posterior uncertainty estimation in the pursuit of
scalability. This work shows that previous Bayesian coreset construction
algorithms---which build a small, weighted subset of the data that approximates
the full dataset---are no exception. We demonstrate that these algorithms scale
the coreset log-likelihood suboptimally, resulting in underestimated posterior
uncertainty. To address this shortcoming, we develop greedy iterative geodesic
ascent (GIGA), a novel algorithm for Bayesian coreset construction that scales
the coreset log-likelihood optimally. GIGA provides geometric decay in
posterior approximation error as a function of coreset size, and maintains the
fast running time of its predecessors. The paper concludes with validation of
GIGA on both synthetic and real datasets, demonstrating that it reduces
posterior approximation error by orders of magnitude compared with previous
coreset constructions. | [
0,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Is there any polynomial upper bound for the universal labeling of graphs?,
Abstract: A {\it universal labeling} of a graph $G$ is a labeling of the edge set in
$G$ such that in every orientation $\ell$ of $G$ for every two adjacent
vertices $v$ and $u$, the sum of incoming edges of $v$ and $u$ in the oriented
graph are different from each other. The {\it universal labeling number} of a
graph $G$ is the minimum number $k$ such that $G$ has {\it universal labeling}
from $\{1,2,\ldots, k\}$ denoted it by $\overrightarrow{\chi_{u}}(G) $. We have
$2\Delta(G)-2 \leq \overrightarrow{\chi_{u}} (G)\leq 2^{\Delta(G)}$, where
$\Delta(G)$ denotes the maximum degree of $G$. In this work, we offer a
provocative question that is:" Is there any polynomial function $f$ such that
for every graph $G$, $\overrightarrow{\chi_{u}} (G)\leq f(\Delta(G))$?".
Towards this question, we introduce some lower and upper bounds on their
parameter of interest. Also, we prove that for every tree $T$,
$\overrightarrow{\chi_{u}}(T)=\mathcal{O}(\Delta^3) $. Next, we show that for a
given 3-regular graph $G$, the universal labeling number of $G$ is 4 if and
only if $G$ belongs to Class 1. Therefore, for a given 3-regular graph $G$, it
is an $ \mathbf{NP} $-complete to determine whether the universal labeling
number of $G$ is 4. Finally, using probabilistic methods, we almost confirm a
weaker version of the problem. | [
1,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Computer Science"
] |
Title: An Empirical Study on Team Formation in Online Games,
Abstract: Online games provide a rich recording of interactions that can contribute to
our understanding of human behavior. One potential lesson is to understand what
motivates people to choose their teammates and how their choices leadto
performance. We examine several hypotheses about team formation using a large,
longitudinal dataset from a team-based online gaming environment. Specifically,
we test how positive familiarity, homophily, and competence determine team
formationin Battlefield 4, a popular team-based game in which players choose
one of two competing teams to play on. Our dataset covers over two months of
in-game interactions between over 380,000 players. We show that familiarity is
an important factorin team formation, while homophily is not. Competence
affects team formation in more nuanced ways: players with similarly high
competence team-up repeatedly, but large variations in competence discourage
repeated interactions. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Quantitative Biology"
] |
Title: Nematic superconductivity in Cu$_{x}$Bi$_{2}$Se$_{3}$: The surface Andreev bound states,
Abstract: We study theoretically the topological surface states (TSSs) and the possible
surface Andreev bound states (SABSs) of Cu$_{x}$Bi$_{2}$Se$_{3}$ which is known
to be a topological insulator at $x=0$. The superconductivity (SC) pairing of
this compound is assumed to have the broken spin-rotation symmetry, similar to
that of the A-phase of $^{3}$He as suggested by recent nuclear-magnetic
resonance experiments. For both spheroidal and corrugated cylindrical Fermi
surfaces with the hexagonal warping terms, we show that the bulk SC gap is
rather anisotropic; the minimum of the gap is negligibly small as comparing to
the maximum of the gap. This would make the fully-gapped pairing effectively
nodal. For a clean system, our results indicate the bulk of this compound to be
a topological superconductor with the SABSs appearing inside the bulk SC gap.
The zero-energy SABSs which are Majorana fermions, together with the TSSs not
gapped by the pairing, produce a zero-energy peak in the surface density of
states (SDOS). The SABSs are expected to be stable against short-range
nonmagnetic impurities, and the local SDOS is calculated around a nonmagnetic
impurity. The relevance of our results to experiments is discussed. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: The structure of a minimal $n$-chart with two crossings II: Neighbourhoods of $Γ_1\cupΓ_{n-1}$,
Abstract: Given a 2-crossing minimal chart $\Gamma$, a minimal chart with two
crossings, set $\alpha=\min\{~i~|~$there exists an edge of label $i$ containing
a white vertex$\}$, and $\beta=\max\{~i~|~$there exists an edge of label $i$
containing a white vertex$\}$. In this paper we study the structure of a
neighbourhood of $\Gamma_\alpha\cup\Gamma_\beta$, and propose a normal form for
2-crossing minimal $n$-charts, here $\Gamma_\alpha$ and $\Gamma_\beta$ mean the
union of all the edges of label $\alpha$ and $\beta$ respectively. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: First-principles-based method for electron localization: Application to monolayer hexagonal boron nitride,
Abstract: We present a first-principles-based many-body typical medium dynamical
cluster approximation method for characterizing electron localization in
disordered structures. This method applied to monolayer hexagonal boron nitride
shows that the presence of a boron vacancies could turn this wide-gap insulator
into a correlated metal. Depending on the strength of the electron
interactions, these calculations suggest that conduction could be obtained at a
boron vacancy concentration as low as $1.0\%$. We also explore the distribution
of the local density of states, a fingerprint of spatial variations, which
allows localized and delocalized states to be distinguished. The presented
method enables the study of disorder-driven insulator-metal transitions not
only in $h$-BN but also in other physical materials. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Materials Science"
] |
Title: A physiology--based parametric imaging method for FDG--PET data,
Abstract: Parametric imaging is a compartmental approach that processes nuclear imaging
data to estimate the spatial distribution of the kinetic parameters governing
tracer flow. The present paper proposes a novel and efficient computational
method for parametric imaging which is potentially applicable to several
compartmental models of diverse complexity and which is effective in the
determination of the parametric maps of all kinetic coefficients. We consider
applications to [{18}F]-fluorodeoxyglucose Positron Emission Tomography
(FDG-PET) data and analyze the two-compartment catenary model describing the
standard FDG metabolization by an homogeneous tissue and the three-compartment
non-catenary model representing the renal physiology. We show uniqueness
theorems for both models. The proposed imaging method starts from the
reconstructed FDG-PET images of tracer concentration and preliminarily applies
image processing algorithms for noise reduction and image segmentation. The
optimization procedure solves pixelwise the non-linear inverse problem of
determining the kinetic parameters from dynamic concentration data through a
regularized Gauss-Newton iterative algorithm. The reliability of the method is
validated against synthetic data, for the two-compartment system, and
experimental real data of murine models, for the renal three-compartment
system. | [
0,
1,
1,
0,
0,
0
] | [
"Quantitative Biology",
"Statistics"
] |
Title: Item Recommendation with Evolving User Preferences and Experience,
Abstract: Current recommender systems exploit user and item similarities by
collaborative filtering. Some advanced methods also consider the temporal
evolution of item ratings as a global background process. However, all prior
methods disregard the individual evolution of a user's experience level and how
this is expressed in the user's writing in a review community. In this paper,
we model the joint evolution of user experience, interest in specific item
facets, writing style, and rating behavior. This way we can generate individual
recommendations that take into account the user's maturity level (e.g.,
recommending art movies rather than blockbusters for a cinematography expert).
As only item ratings and review texts are observables, we capture the user's
experience and interests in a latent model learned from her reviews, vocabulary
and writing style. We develop a generative HMM-LDA model to trace user
evolution, where the Hidden Markov Model (HMM) traces her latent experience
progressing over time -- with solely user reviews and ratings as observables
over time. The facets of a user's interest are drawn from a Latent Dirichlet
Allocation (LDA) model derived from her reviews, as a function of her (again
latent) experience level. In experiments with five real-world datasets, we show
that our model improves the rating prediction over state-of-the-art baselines,
by a substantial margin. We also show, in a use-case study, that our model
performs well in the assessment of user experience levels. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: On some integrals of Hardy,
Abstract: We consider some properties of integrals considered by Hardy and Koshliakov,
and which have also been further extended recently by Dixit. We establish a new
general integral formula from some observations about the digamma function. We
also obtain lower and upper bounds for Hardy's integral through properties of
the digamma function. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Complexity of short generating functions,
Abstract: We give complexity analysis of the class of short generating functions (GF).
Assuming $\#P \not\subseteq FP/poly$, we show that this class is not closed
under taking many intersections, unions or projections of GFs, in the sense
that these operations can increase the bitlength of coefficients of GFs by a
super-polynomial factor. We also prove that truncated theta functions are hard
in this class. | [
1,
0,
1,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Finite-Size Effects in Non-Neutral Two-Dimensional Coulomb Fluids,
Abstract: Thermodynamic potential of a neutral two-dimensional (2D) Cou\-lomb fluid,
confined to a large domain with a smooth boundary, exhibits at any (inverse)
temperature $\beta$ a logarithmic finite-size correction term whose universal
prefactor depends only on the Euler number of the domain and the conformal
anomaly number $c=-1$. A minimal free boson conformal field theory, which is
equivalent to the 2D symmetric two-component plasma of elementary $\pm e$
charges at coupling constant $\Gamma=\beta e^2$, was studied in the past. It
was shown that creating a non-neutrality by spreading out a charge $Q e$ at
infinity modifies the anomaly number to $c(Q,\Gamma) = - 1 + 3\Gamma Q^2$.
Here, we study the effect of non-neutrality on the finite-size expansion of the
free energy for another Coulomb fluid, namely the 2D one-component plasma
(jellium) composed of identical pointlike $e$-charges in a homogeneous
background surface charge density. For the disk geometry of the confining
domain we find that the non-neutrality induces the same change of the anomaly
number in the finite-size expansion. We derive this result first at the
free-fermion coupling $\Gamma\equiv\beta e^2=2$ and then, by using a mapping of
the 2D one-component plasma onto an anticommuting field theory formulated on a
chain, for an arbitrary coupling constant. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Mathematics"
] |
Title: Type Safe Redis Queries: A Case Study of Type-Level Programming in Haskell,
Abstract: Redis is an in-memory data structure store, often used as a database, with a
Haskell interface Hedis. Redis is dynamically typed --- a key can be discarded
and re-associated to a value of a different type, and a command, when fetching
a value of a type it does not expect, signals a runtime error. We develop a
domain-specific language that, by exploiting Haskell type-level programming
techniques including indexed monad, type-level literals and closed type
families, keeps track of types of values in the database and statically
guarantees that type errors cannot happen for a class of Redis programs. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Long-range p-d exchange interaction in a ferromagnet-semiconductor Co/CdMgTe/CdTe quantum well hybrid structure,
Abstract: The exchange interaction between magnetic ions and charge carriers in
semiconductors is considered as prime tool for spin control. Here, we solve a
long-standing problem by uniquely determining the magnitude of the long-range
$p-d$ exchange interaction in a ferromagnet-semiconductor (FM-SC) hybrid
structure where a 10~nm thick CdTe quantum well is separated from the FM Co
layer by a CdMgTe barrier with a thickness on the order of 10~nm. The exchange
interaction is manifested by the spin splitting of acceptor bound holes in the
effective magnetic field induced by the FM. The exchange splitting is directly
evaluated using spin-flip Raman scattering by analyzing the dependence of the
Stokes shift $\Delta_S$ on the external magnetic field $B$. We show that in
strong magnetic field $\Delta_S$ is a linear function of $B$ with an offset of
$\Delta_{pd} = 50-100~\mu$eV at zero field from the FM induced effective
exchange field. On the other hand, the $s-d$ exchange interaction between
conduction band electrons and FM, as well as the $p-d$ contribution for free
valence band holes, are negligible. The results are well described by the model
of indirect exchange interaction between acceptor bound holes in the CdTe
quantum well and the FM layer mediated by elliptically polarized phonons in the
hybrid structure. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Positive scalar curvature and connected sums,
Abstract: Let $N$ be a closed enlargeable manifold in the sense of Gromov-Lawson and
$M$ a closed spin manifold of equal dimension, a famous theorem of
Gromov-Lawson states that the connected sum $M\# N$ admits no metric of
positive scalar curvature. We present a potential generalization of this result
to the case where $M$ is nonspin. We use index theory for Dirac operators to
prove our result. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: On the joint asymptotic distribution of the restricted estimators in multivariate regression model,
Abstract: The main Theorem of Jain et al.[Jain, K., Singh, S., and Sharma, S. (2011),
Re- stricted estimation in multivariate measurement error regression model;
JMVA, 102, 2, 264-280] is established in its full generality. Namely, we derive
the joint asymp- totic normality of the unrestricted estimator (UE) and the
restricted estimators of the matrix of the regression coefficients. The derived
result holds under the hypothesized restriction as well as under the sequence
of alternative restrictions. In addition, we establish Asymptotic
Distributional Risk for the estimators and compare their relative performance.
It is established that near the restriction, the restricted estimators (REs)
perform better than the UE. But the REs perform worse than the unrestricted
estimator when one moves far away from the restriction. | [
0,
0,
1,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: Rotational spectroscopy, tentative interstellar detection, and chemical modelling of N-methylformamide,
Abstract: N-methylformamide, CH3NHCHO, may be an important molecule for interstellar
pre-biotic chemistry because it contains a peptide bond. The rotational
spectrum of the most stable trans conformer of CH3NHCHO is complicated by
strong torsion-rotation interaction due to the low barrier of the methyl
torsion. We use two absorption spectrometers in Kharkiv and Lille to measure
the rotational spectra over 45--630 GHz. The analysis is carried out using the
Rho-axis method and the RAM36 code. We search for N-methylformamide toward the
hot molecular core Sgr B2(N2) using a spectral line survey carried out with
ALMA. The astronomical results are put into a broader astrochemical context
with the help of a gas-grain chemical kinetics model. The laboratory data set
for the trans conformer of CH3NHCHO consists of 9469 line frequencies with J <=
62, including the first assignment of the rotational spectra of the first and
second excited torsional states. All these lines are fitted within experimental
accuracy. We report the tentative detection of CH3NHCHO towards Sgr B2(N2). We
find CH3NHCHO to be more than one order of magnitude less abundant than NH2CHO,
a factor of two less abundant than CH3NCO, but only slightly less abundant than
CH3CONH2. The chemical models indicate that the efficient formation of HNCO via
NH + CO on grains is a necessary step in the achievement of the observed
gas-phase abundance of CH3NCO. Production of CH3NHCHO may plausibly occur on
grains either through the direct addition of functional-group radicals or
through the hydrogenation of CH3NCO. Provided the detection of CH3NHCHO is
confirmed, the only slight underabundance of this molecule compared to its more
stable structural isomer acetamide and the sensitivity of the model abundances
to the chemical kinetics parameters suggest that the formation of these two
molecules is controlled by kinetics rather than thermal equilibrium. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Quantitative Biology"
] |
Title: Dealing with the exponential wall in electronic structure calculations,
Abstract: An alternative to Density Functional Theory are wavefunction based electronic
structure calculations for solids. In order to perform them the Exponential
Wall (EW) problem has to be resolved. It is caused by an exponential increase
of the number of configurations with increasing electron number N. There are
different routes one may follow. One is to characterize a many-electron
wavefunction by a vector in Liouville space with a cumulant metric rather than
in Hilbert space. This removes the EW problem. Another is to model the solid by
an {\it impurity} or {\it fragment} embedded in a {\it bath} which is treated
at a much lower level than the former. This is the case in Density Matrix
Embedding Theory (DMET) or Density Embedding Theory (DET). The latter are
closely related to a Schmidt decomposition of a system and to the determination
of the associated entanglement. We show here the connection between the two
approaches. It turns out that the DMET (or DET) has an identical active space
as a previously used Local Ansatz, based on a projection and partitioning
approach. Yet, the EW problem is resolved differently in the two cases. By
studying a $H_{10}$ ring these differences are analyzed with the help of the
method of increments. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Mathematics"
] |
Title: Influence maximization on correlated networks through community identification,
Abstract: The identification of the minimal set of nodes that maximizes the propagation
of information is one of the most important problems in network science. In
this paper, we introduce a new method to find the set of initial spreaders to
maximize the information propagation in complex networks. We evaluate this
method in assortative networks and verify that degree-degree correlation plays
a fundamental role on the spreading dynamics. Simulation results show that our
algorithm is statistically similar, in terms of the average size of outbreaks,
to the greedy approach. However, our method is much less time consuming than
the greedy algorithm. | [
1,
1,
0,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: A Short Review of Ethical Challenges in Clinical Natural Language Processing,
Abstract: Clinical NLP has an immense potential in contributing to how clinical
practice will be revolutionized by the advent of large scale processing of
clinical records. However, this potential has remained largely untapped due to
slow progress primarily caused by strict data access policies for researchers.
In this paper, we discuss the concern for privacy and the measures it entails.
We also suggest sources of less sensitive data. Finally, we draw attention to
biases that can compromise the validity of empirical research and lead to
socially harmful applications. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Quantitative Biology"
] |
Title: A Heat Equation on some Adic Completions of Q and Ultrametric Analysis,
Abstract: This article deals with a Markov process related to the fundamental solution
of a heat equation on the direct product ring Q_S, where Q_S is a finite direct
product of p-adic fields. The techniques developed here are different from the
well known ones: they are geometrical and very simple. As a result, the
techniques developed here provides a general framework of these problems on
other related ultrametric groups. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Physics"
] |
Title: Interpretable Active Learning,
Abstract: Active learning has long been a topic of study in machine learning. However,
as increasingly complex and opaque models have become standard practice, the
process of active learning, too, has become more opaque. There has been little
investigation into interpreting what specific trends and patterns an active
learning strategy may be exploring. This work expands on the Local
Interpretable Model-agnostic Explanations framework (LIME) to provide
explanations for active learning recommendations. We demonstrate how LIME can
be used to generate locally faithful explanations for an active learning
strategy, and how these explanations can be used to understand how different
models and datasets explore a problem space over time. In order to quantify the
per-subgroup differences in how an active learning strategy queries spatial
regions, we introduce a notion of uncertainty bias (based on disparate impact)
to measure the discrepancy in the confidence for a model's predictions between
one subgroup and another. Using the uncertainty bias measure, we show that our
query explanations accurately reflect the subgroup focus of the active learning
queries, allowing for an interpretable explanation of what is being learned as
points with similar sources of uncertainty have their uncertainty bias
resolved. We demonstrate that this technique can be applied to track
uncertainty bias over user-defined clusters or automatically generated clusters
based on the source of uncertainty. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Orbital-Free Density-Functional Theory Simulations of Displacement Cascade in Aluminum,
Abstract: Here, we report orbital-free density-functional theory (OF DFT) molecular
dynamics simulations of the displacement cascade in aluminum. The electronic
effect is our main concern. The displacement threshold energies are calculated
using OF DFT and classical molecular dynamics (MD) and the comparison reveals
the role of charge bridge. Compared to MD simulation, the displacement spike
from OF DFT has a lower peak and shorter duration time, which is attributed to
the effect of electronic damping. The charge density profiles clearly display
the existence of depleted zones, vacancy and interstitial clusters. And it is
found that the energy exchanges between ions and electrons are mainly
contributed by the kinetic energies. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Computer Science"
] |
Title: DNA methylation markers to assess biological age,
Abstract: Among the different biomarkers of aging based on omics and clinical data, DNA
methylation clocks stand apart providing unmatched accuracy in assessing the
biological age of both humans and animal models of aging. Here, we discuss
robustness of DNA methylation clocks and bounds on their out-of-sample
performance and review computational strategies for development of the clocks. | [
0,
0,
0,
0,
1,
0
] | [
"Quantitative Biology",
"Statistics"
] |
Title: Towards Building an Intelligent Anti-Malware System: A Deep Learning Approach using Support Vector Machine (SVM) for Malware Classification,
Abstract: Effective and efficient mitigation of malware is a long-time endeavor in the
information security community. The development of an anti-malware system that
can counteract an unknown malware is a prolific activity that may benefit
several sectors. We envision an intelligent anti-malware system that utilizes
the power of deep learning (DL) models. Using such models would enable the
detection of newly-released malware through mathematical generalization. That
is, finding the relationship between a given malware $x$ and its corresponding
malware family $y$, $f: x \mapsto y$. To accomplish this feat, we used the
Malimg dataset (Nataraj et al., 2011) which consists of malware images that
were processed from malware binaries, and then we trained the following DL
models 1 to classify each malware family: CNN-SVM (Tang, 2013), GRU-SVM
(Agarap, 2017), and MLP-SVM. Empirical evidence has shown that the GRU-SVM
stands out among the DL models with a predictive accuracy of ~84.92%. This
stands to reason for the mentioned model had the relatively most sophisticated
architecture design among the presented models. The exploration of an even more
optimal DL-SVM model is the next stage towards the engineering of an
intelligent anti-malware system. | [
0,
0,
0,
1,
0,
0
] | [
"Computer Science"
] |
Title: Exponential profiles from stellar scattering off interstellar clumps and holes in dwarf galaxy discs,
Abstract: Holes and clumps in the interstellar gas of dwarf irregular galaxies are
gravitational scattering centers that heat field stars and change their radial
and vertical distributions. Because the gas structures are extended and each
stellar scattering is relatively weak, the stellar orbits remain nearly
circular and the net effect accumulates slowly over time. We calculate the
radial profile of scattered stars with an idealized model and find that it
approaches an equilibrium shape that is exponential, similar to the observed
shapes of galaxy discs. Our models treat only scattering and have no bars or
spiral arms, so the results apply mostly to dwarf irregular galaxies where
there are no other obvious scattering processes. Stellar scattering by gaseous
perturbations slows down when the stellar population gets thicker than the gas
layer. An accreting galaxy with a growing thin gas layer can form multiple
stellar exponential profiles from the inside-out, preserving the remnants of
each Gyr interval in a sequence of ever-lengthening and thinning stellar
subdiscs. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Objective-Reinforced Generative Adversarial Networks (ORGAN) for Sequence Generation Models,
Abstract: In unsupervised data generation tasks, besides the generation of a sample
based on previous observations, one would often like to give hints to the model
in order to bias the generation towards desirable metrics. We propose a method
that combines Generative Adversarial Networks (GANs) and reinforcement learning
(RL) in order to accomplish exactly that. While RL biases the data generation
process towards arbitrary metrics, the GAN component of the reward function
ensures that the model still remembers information learned from data. We build
upon previous results that incorporated GANs and RL in order to generate
sequence data and test this model in several settings for the generation of
molecules encoded as text sequences (SMILES) and in the context of music
generation, showing for each case that we can effectively bias the generation
process towards desired metrics. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Pluripotential theory on the support of closed positive currents and applications to dynamics in $\mathbb{C}^n$,
Abstract: We extend certain classical theorems in pluripotential theory to a class of
functions defined on the support of a $(1,1)$-closed positive current $T$,
analogous to plurisubharmonic functions, called $T$-plurisubharmonic functions.
These functions are defined as limits, on the support of $T$, of sequences of
plurisubharmonic functions decreasing on this support. In particular, we show
that the poles of such functions are pluripolar sets. We also show that the
maximum principle and the Hartogs's theorem remain valid in a weak sense. We
study these functions by means of a class of measures, so-called "pluri-Jensen
measures", about which we prove that they are numerous on the support of
$(1,1)$-closed positive currents. We also obtain, for any fat compact set, an
expression of its relative Green's function in terms of an infimum of an
integral over a set of pluri-Jensen measures. We then deduce, by means of these
measures, a characterization of the polynomially convex fat compact sets, as
well as a characterization of pluripolar sets, and the fact that the support of
a closed positive $(1,1)$-current is nowhere pluri-thin. In the second part of
this article, these tools are used to study dynamics of a certain class of
automorphisms of $\mathbb{C}^n$ which naturally generalize Hénon's
automorphisms of $\mathbb{C}^2$. First we study the geometry of the support of
canonical invariant currents. Then we obtain an equidistribution result for the
convergence of pull-back of certain measures towards an ergodic invariant
measure, with compact support. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Adaptive User Perspective Rendering for Handheld Augmented Reality,
Abstract: Handheld Augmented Reality commonly implements some variant of magic lens
rendering, which turns only a fraction of the user's real environment into AR
while the rest of the environment remains unaffected. Since handheld AR devices
are commonly equipped with video see-through capabilities, AR magic lens
applications often suffer from spatial distortions, because the AR environment
is presented from the perspective of the camera of the mobile device. Recent
approaches counteract this distortion based on estimations of the user's head
position, rendering the scene from the user's perspective. To this end,
approaches usually apply face-tracking algorithms on the front camera of the
mobile device. However, this demands high computational resources and therefore
commonly affects the performance of the application beyond the already high
computational load of AR applications. In this paper, we present a method to
reduce the computational demands for user perspective rendering by applying
lightweight optical flow tracking and an estimation of the user's motion before
head tracking is started. We demonstrate the suitability of our approach for
computationally limited mobile devices and we compare it to device perspective
rendering, to head tracked user perspective rendering, as well as to fixed
point of view user perspective rendering. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Inverse dynamic and spectral problems for the one-dimensional Dirac system on a finite tree,
Abstract: We consider inverse dynamic and spectral problems for the one dimensional
Dirac system on a finite tree. Our aim will be to recover the topology of a
tree (lengths and connectivity of edges) as well as matrix potentials on each
edge. As inverse data we use the Weyl-Titchmarsh matrix function or the dynamic
response operator. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Physics"
] |
Title: Simplified derivation of the collision probability of two objects in independent Keplerian orbits,
Abstract: Many topics in planetary studies demand an estimate of the collision
probability of two objects moving on nearly Keplerian orbits. In the classic
works of Öpik (1951) and Wetherill (1967), the collision probability was
derived by linearizing the motion near the collision points, and there is now a
vast literature using their method. We present here a simpler and more
physically motivated derivation for non-tangential collisions in Keplerian
orbits, as well as for tangential collisions that were not previously
considered. Our formulas have the added advantage of being manifestly symmetric
in the parameters of the two colliding bodies. In common with the
Öpik-Wetherill treatments, we linearize the motion of the bodies in the
vicinity of the point of orbit intersection (or near the points of minimum
distance between the two orbits) and assume a uniform distribution of impact
parameter within the collision radius. We point out that the linear
approximation leads to singular results for the case of tangential encounters.
We regularize this singularity by use of a parabolic approximation of the
motion in the vicinity of a tangential encounter. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Mathematics"
] |
Title: Electron-phonon coupling mechanisms for hydrogen-rich metals at high pressure,
Abstract: The mechanisms for strong electron-phonon coupling predicted for
hydrogen-rich alloys with high superconducting critical temperature ($T_c$) are
examined within the Migdal-Eliashberg theory. Analysis of the functional
derivative of $T_c$ with respect to the electron-phonon spectral function shows
that at low pressures, when the alloys often adopt layered structures, bending
vibrations have the most dominant effect. At very high pressures, the H-H
interactions in two-dimensional (2D) and three-dimensional (3D) extended
structures are weakened, resulting in mixed bent (libration) and stretch
vibrations, and the electron-phonon coupling process is distributed over a
broad frequency range leading to very high $T_c$. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Competitive Equilibrium For almost All Incomes,
Abstract: Competitive equilibrium from equal incomes (CEEI) is a well-known rule for
fair allocation of resources among agents with different preferences. It has
many advantages, among them is the fact that a CEEI allocation is both Pareto
efficient and envy-free. However, when the resources are indivisible, a CEEI
allocation might not exist even when there are two agents and a single item.
In contrast to this discouraging non-existence result, Babaioff, Nisan and
Talgam-Cohen (2017) recently suggested a new and more encouraging approach to
allocation of indivisible items: instead of insisting that the incomes be
equal, they suggest to look at the entire space of possible incomes, and check
whether there exists a competitive equilibrium for almost all income-vectors
(CEFAI) --- all income-space except a subset of measure zero. They show that a
CEFAI exists when there are at most 3 items, or when there are 4 items and two
agents. They also show that when there are 5 items and two agents there might
not exist a CEFAI. They leave open the cases of 4 items with three or four
agents.
This paper presents a new way to implement a CEFAI, as a subgame-perfect
equilibrium of a sequential game. This new implementation allows us both to
offer much simpler solutions to the known cases (at most 3 items, and 4 items
with two agents), and to prove that a CEFAI exists even in the much more
difficult case of 4 items and three agents. Moreover, we prove that a CEFAI
might not exist with 4 items and four agents. When the items to be divided are
bads (chores), CEFAI exists for two agents with at most 4 chores, but does not
exist for two agents with 5 chores or with three agents with 3 or more chores.
Thus, this paper completes the characterization of CEFAI existence for monotone
preferences. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Converting of algebraic Diophantine equations to a diagonal form with the help of an integer non-orthogonal transformation, maintaining the asymptotic behavior of the number of its integer solutions,
Abstract: The author showed that any homogeneous algebraic Diophantine equation of the
second order can be converted to a diagonal form using an integer
non-orthogonal transformation maintaining asymptotic behavior of the number of
its integer solutions. In this paper, we consider the transformation to the
diagonal form of a wider class of algebraic second-order Diophantine equations,
and also we consider the conditions for converting higher order algebraic
Diophantine equations to this form. The author found an asymptotic estimate for
the number of integer solutions of the diagonal Thue equation of odd degree
with an amount of variables greater than two, and also he got and asymptotic
estimates of the number of integer solutions of other types of diagonal
algebraic Diophantine equations. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: A Deep Learning Approach with an Attention Mechanism for Automatic Sleep Stage Classification,
Abstract: Automatic sleep staging is a challenging problem and state-of-the-art
algorithms have not yet reached satisfactory performance to be used instead of
manual scoring by a sleep technician. Much research has been done to find good
feature representations that extract the useful information to correctly
classify each epoch into the correct sleep stage. While many useful features
have been discovered, the amount of features have grown to an extent that a
feature reduction step is necessary in order to avoid the curse of
dimensionality. One reason for the need of such a large feature set is that
many features are good for discriminating only one of the sleep stages and are
less informative during other stages. This paper explores how a second feature
representation over a large set of pre-defined features can be learned using an
auto-encoder with a selective attention for the current sleep stage in the
training batch. This selective attention allows the model to learn feature
representations that focuses on the more relevant inputs without having to
perform any dimensionality reduction of the input data. The performance of the
proposed algorithm is evaluated on a large data set of polysomnography (PSG)
night recordings of patients with sleep-disordered breathing. The performance
of the auto-encoder with selective attention is compared with a regular
auto-encoder and previous works using a deep belief network (DBN). | [
0,
0,
0,
0,
1,
0
] | [
"Computer Science",
"Quantitative Biology"
] |
Title: Barcode Embeddings for Metric Graphs,
Abstract: Stable topological invariants are a cornerstone of persistence theory and
applied topology, but their discriminative properties are often
poorly-understood. In this paper we study a rich homology-based invariant first
defined by Dey, Shi, and Wang, which we think of as embedding a metric graph in
the barcode space. We prove that this invariant is locally injective on the
space of metric graphs and globally injective on a GH-dense subset. Moreover,
we define a new topology on the space of metric graphs, which we call the
fibered topology, for which the barcode transform is injective on a generic
(open and dense) subset. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Note on the geodesic Monte Carlo,
Abstract: Geodesic Monte Carlo (gMC) is a powerful algorithm for Bayesian inference on
non-Euclidean manifolds. The original gMC algorithm was cleverly derived in
terms of its progenitor, the Riemannian manifold Hamiltonian Monte Carlo
(RMHMC). Here, it is shown that alternative and theoretically simpler
derivations are available in which the original algorithm is a special case of
two general classes of algorithms characterized by non-trivial mass matrices.
The proposed derivations work entirely in embedding coordinates and thus
clarify the original algorithm as applied to manifolds embedded in Euclidean
space. | [
0,
0,
0,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: Google Scholar and the gray literature: A reply to Bonato's review,
Abstract: Recently, a review concluded that Google Scholar (GS) is not a suitable
source of information "for identifying recent conference papers or other gray
literature publications". The goal of this letter is to demonstrate that GS can
be an effective tool to search and find gray literature, as long as appropriate
search strategies are used. To do this, we took as examples the same two case
studies used by the original review, describing first how GS processes
original's search strategies, then proposing alternative search strategies, and
finally generalizing each case study to compose a general search procedure
aimed at finding gray literature in Google Scholar for two wide selected case
studies: a) all contributions belonging to a congress (the ASCO Annual
Meeting); and b) indexed guidelines as well as gray literature within medical
institutions (National Institutes of Health) and governmental agencies (U.S.
Department of Health & Human Services). The results confirm that original
search strategies were undertrained offering misleading results and erroneous
conclusions. Google Scholar lacks many of the advanced search features
available in other bibliographic databases (such as Pubmed), however, it is one
thing to have a friendly search experience, and quite another to find gray
literature. We finally conclude that Google Scholar is a powerful tool for
searching gray literature, as long as the users are familiar with all the
possibilities it offers as a search engine. Poorly formulated searches will
undoubtedly return misleading results. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Spectral up- and downshifting of Akhmediev breathers under wind forcing,
Abstract: We experimentally and numerically investigate the effect of wind forcing on
the spectral dynamics of Akhmediev breathers, a wave-type known to model the
modulation instability. We develop the wind model to the same order in
steepness as the higher order modifcation of the nonlinear Schroedinger
equation, also referred to as the Dysthe equation. This results in an
asymmetric wind term in the higher order, in addition to the leading order wind
forcing term. The derived model is in good agreement with laboratory
experiments within the range of the facility's length. We show that the leading
order forcing term amplifies all frequencies equally and therefore induces only
a broadening of the spectrum while the asymmetric higher order term in the
model enhances higher frequencies more than lower ones. Thus, the latter term
induces a permanent upshift of the spectral mean. On the other hand, in
contrast to the direct effect of wind forcing, wind can indirectly lead to
frequency downshifts, due to dissipative effects such as wave breaking, or
through amplification of the intrinsic spectral asymmetry of the Dysthe
equation. Furthermore, the definitions of the up- and downshift in terms of
peak- and mean frequencies, that are critical to relate our work to previous
results, are highlighted and discussed. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: On parabolic subgroups of Artin-Tits groups of spherical type,
Abstract: We show that, in an Artin-Tits group of spherical type, the intersection of
two parabolic subgroups is a parabolic subgroup. Moreover, we show that the set
of parabolic subgroups forms a lattice with respect to inclusion. This extends
to all Artin-Tits groups of spherical type a result that was previously known
for braid groups.
To obtain the above results, we show that every element in an Artin-Tits
group of spherical type admits a unique minimal parabolic subgroup containing
it. Also, the subgroup associated to an element coincides with the subgroup
associated to any of its powers or roots. As a consequence, if an element
belongs to a parabolic subgroup, all its roots belong to the same parabolic
subgroup.
We define the simplicial complex of irreducible parabolic subgroups, and we
propose it as the analogue, in Artin-Tits groups of spherical type, of the
celebrated complex of curves which is an important tool in braid groups, and
more generally in mapping class groups. We conjecture that the complex of
irreducible parabolic subgroups is $\delta$-hyperbolic. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: A statistical test for the Zipf's law by deviations from the Heaps' law,
Abstract: We explore a probabilistic model of an artistic text: words of the text are
chosen independently of each other in accordance with a discrete probability
distribution on an infinite dictionary. The words are enumerated 1, 2,
$\ldots$, and the probability of appearing the $i$'th word is asymptotically a
power function. Bahadur proved that in this case the number of different words
depends on the length of the text is asymptotically a power function, too. On
the other hand, in the applied statistics community, there exist statements
supported by empirical observations, the Zipf's and the Heaps' laws. We
highlight the links between Bahadur results and Zipf's/Heaps' laws, and
introduce and analyse a corresponding statistical test. | [
0,
0,
1,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: Profit Driven Decision Trees for Churn Prediction,
Abstract: Customer retention campaigns increasingly rely on predictive models to detect
potential churners in a vast customer base. From the perspective of machine
learning, the task of predicting customer churn can be presented as a binary
classification problem. Using data on historic behavior, classification
algorithms are built with the purpose of accurately predicting the probability
of a customer defecting. The predictive churn models are then commonly selected
based on accuracy related performance measures such as the area under the ROC
curve (AUC). However, these models are often not well aligned with the core
business requirement of profit maximization, in the sense that, the models fail
to take into account not only misclassification costs, but also the benefits
originating from a correct classification. Therefore, the aim is to construct
churn prediction models that are profitable and preferably interpretable too.
The recently developed expected maximum profit measure for customer churn
(EMPC) has been proposed in order to select the most profitable churn model. We
present a new classifier that integrates the EMPC metric directly into the
model construction. Our technique, called ProfTree, uses an evolutionary
algorithm for learning profit driven decision trees. In a benchmark study with
real-life data sets from various telecommunication service providers, we show
that ProfTree achieves significant profit improvements compared to classic
accuracy driven tree-based methods. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics",
"Quantitative Finance"
] |
Title: Gradient-based Training of Slow Feature Analysis by Differentiable Approximate Whitening,
Abstract: This paper proposes Power Slow Feature Analysis, a gradient-based method to
extract temporally-slow features from a high-dimensional input stream that
varies on a faster time-scale, and a variant of Slow Feature Analysis (SFA).
While displaying performance comparable to hierarchical extensions to the SFA
algorithm, such as Hierarchical Slow Feature Analysis, for a small number of
output-features, our algorithm allows end-to-end training of arbitrary
differentiable approximators (e.g., deep neural networks). We provide
experimental evidence that PowerSFA is able to extract meaningful and
informative low-dimensional features in the case of a) synthetic
low-dimensional data, b) visual data, and also for c) a general dataset for
which symmetric non-temporal relations between points can be defined. | [
0,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Quantum Critical Behavior in the Asymptotic Limit of High Disorder: Entropy Stabilized NiCoCr0.8 Alloys,
Abstract: The behavior of matter near a quantum critical point (QCP) is one of the most
exciting and challenging areas of physics research. Emergent phenomena such as
high-temperature superconductivity are linked to the proximity to a QCP.
Although significant progress has been made in understanding quantum critical
behavior in some low dimensional magnetic insulators, the situation in metallic
systems is much less clear. Here we demonstrate that NiCoCrx single crystal
alloys are remarkable model systems for investigating QCP physics in a metallic
environment. For NiCoCrx alloys with x = 0.8, the critical exponents associated
with a ferromagnetic quantum critical point (FQCP) are experimentally
determined from low temperature magnetization and heat capacity measurements.
For the first time, all of the five critical exponents ( gamma-subT =1/2 ,
beta-subT = 1, delta = 3/2, nuz-subm = 2, alpha-bar-subT = 0) are in remarkable
agreement with predictions of Belitz-Kirkpatrick-Vojta (BKV) theory in the
asymptotic limit of high disorder. Using these critical exponents, excellent
scaling of the magnetization data is demonstrated with no adjustable
parameters. We also find a divergence of the magnetic Gruneisen parameter,
consistent with a FQCP. This work therefore demonstrates that entropy
stabilized concentrated solid solutions represent a unique platform to study
quantum critical behavior in a highly tunable class of materials. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Fast, Autonomous Flight in GPS-Denied and Cluttered Environments,
Abstract: One of the most challenging tasks for a flying robot is to autonomously
navigate between target locations quickly and reliably while avoiding obstacles
in its path, and with little to no a-priori knowledge of the operating
environment. This challenge is addressed in the present paper. We describe the
system design and software architecture of our proposed solution, and showcase
how all the distinct components can be integrated to enable smooth robot
operation. We provide critical insight on hardware and software component
selection and development, and present results from extensive experimental
testing in real-world warehouse environments. Experimental testing reveals that
our proposed solution can deliver fast and robust aerial robot autonomous
navigation in cluttered, GPS-denied environments. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Robotics"
] |
Title: The Berkovich realization for rigid analytic motives,
Abstract: We prove that the functor associating to a rigid analytic variety the
singular complex of the underlying Berkovich topological space is motivic, and
defines the maximal Artin quotient of a motive. We use this to generalize
Berkovich's results on the weight-zero part of the étale cohomology of a
variety defined over a non-archimedean valued field. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Detection of sub-MeV Dark Matter with Three-Dimensional Dirac Materials,
Abstract: We propose the use of three-dimensional Dirac materials as targets for direct
detection of sub-MeV dark matter. Dirac materials are characterized by a linear
dispersion for low-energy electronic excitations, with a small band gap of
O(meV) if lattice symmetries are broken. Dark matter at the keV scale carrying
kinetic energy as small as a few meV can scatter and excite an electron across
the gap. Alternatively, bosonic dark matter as light as a few meV can be
absorbed by the electrons in the target. We develop the formalism for dark
matter scattering and absorption in Dirac materials and calculate the
experimental reach of these target materials. We find that Dirac materials can
play a crucial role in detecting dark matter in the keV to MeV mass range that
scatters with electrons via a kinetically mixed dark photon, as the dark photon
does not develop an in-medium effective mass. The same target materials provide
excellent sensitivity to absorption of light bosonic dark matter in the meV to
hundreds of meV mass range, superior to all other existing proposals when the
dark matter is a kinetically mixed dark photon. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Formation of Local Resonance Band Gaps in Finite Acoustic Metamaterials: A Closed-form Transfer Function Model,
Abstract: The objective of this paper is to use transfer functions to comprehend the
formation of band gaps in locally resonant acoustic metamaterials. Identifying
a recursive approach for any number of serially arranged locally resonant mass
in mass cells, a closed form expression for the transfer function is derived.
Analysis of the end-to-end transfer function helps identify the fundamental
mechanism for the band gap formation in a finite metamaterial. This mechanism
includes (a) repeated complex conjugate zeros located at the natural frequency
of the individual local resonators, (b) the presence of two poles which flank
the band gap, and (c) the absence of poles in the band-gap. Analysis of the
finite cell dynamics are compared to the Bloch-wave analysis of infinitely long
metamaterials to confirm the theoretical limits of the band gap estimated by
the transfer function modeling. The analysis also explains how the band gap
evolves as the number of cells in the metamaterial chain increases and
highlights how the response varies depending on the chosen sensing location
along the length of the metamaterial. The proposed transfer function approach
to compute and evaluate band gaps in locally resonant structures provides a
framework for the exploitation of control techniques to modify and tune band
gaps in finite metamaterial realizations. | [
0,
1,
1,
0,
0,
0
] | [
"Physics",
"Mathematics"
] |
Title: Mutual Alignment Transfer Learning,
Abstract: Training robots for operation in the real world is a complex, time consuming
and potentially expensive task. Despite significant success of reinforcement
learning in games and simulations, research in real robot applications has not
been able to match similar progress. While sample complexity can be reduced by
training policies in simulation, such policies can perform sub-optimally on the
real platform given imperfect calibration of model dynamics. We present an
approach -- supplemental to fine tuning on the real robot -- to further benefit
from parallel access to a simulator during training and reduce sample
requirements on the real robot. The developed approach harnesses auxiliary
rewards to guide the exploration for the real world agent based on the
proficiency of the agent in simulation and vice versa. In this context, we
demonstrate empirically that the reciprocal alignment for both agents provides
further benefit as the agent in simulation can adjust to optimize its behaviour
for states commonly visited by the real-world agent. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Scalar and Tensor Parameters for Importing Tensor Index Notation including Einstein Summation Notation,
Abstract: In this paper, we propose a method for importing tensor index notation,
including Einstein summation notation, into functional programming. This method
involves introducing two types of parameters, i.e, scalar and tensor
parameters, and simplified tensor index rules that do not handle expressions
that are valid only for the Cartesian coordinate system, in which the index can
move up and down freely. An example of such an expression is "c = A_i B_i". As
an ordinary function, when a tensor parameter obtains a tensor as an argument,
the function treats the tensor argument as a whole. In contrast, when a scalar
parameter obtains a tensor as an argument, the function is applied to each
component of the tensor. In this paper, we show that introducing these two
types of parameters and our simplified index rules enables us to apply
arbitrary user-defined functions to tensor arguments using index notation
including Einstein summation notation without requiring an additional
description to enable each function to handle tensors. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Mathematics"
] |
Title: Dynamics and transverse relaxation of an unconventional spin-rotation mode in a two-dimensional strongly magnetized electron gas,
Abstract: An unconventional spin-rotation mode emerging in a quantum Hall ferromagnet
due to excitation by a laser pulse is studied. This state, macroscopically
representing a rotation of the entire electron spin-system to a certain angle,
microscopically is not equivalent to a coherent turn of all spins as a
single-whole and is presented in the form of a combination of eigen quantum
states corresponding to all possible S_z spin numbers. Motion of the
macroscopic quantum state is studied microscopically by solving a
non-stationary Schroedinger equation and by means of a kinetic approach where
damping of the spin-rotation mode is related to an elementary process -
transformation of a 'Goldstone spin exciton' to a 'spin-wave exciton'. The
system exhibits a spin stochastization mechanism (determined by spatial
fluctuations of the g-factor) providing the damping - the transverse spin
relaxation, but irrelevant to a decay of spin-wave excitons and thus not
providing the longitudinal relaxation - recovery of the S_z number to its
equilibrium value. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Torsion of elliptic curves and unlikely intersections,
Abstract: We study effective versions of unlikely intersections of images of torsion
points of elliptic curves on the projective line. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: BoostJet: Towards Combining Statistical Aggregates with Neural Embeddings for Recommendations,
Abstract: Recommenders have become widely popular in recent years because of their
broader applicability in many e-commerce applications. These applications rely
on recommenders for generating advertisements for various offers or providing
content recommendations. However, the quality of the generated recommendations
depends on user features (like demography, temporality), offer features (like
popularity, price), and user-offer features (like implicit or explicit
feedback). Current state-of-the-art recommenders do not explore such diverse
features concurrently while generating the recommendations.
In this paper, we first introduce the notion of Trackers which enables us to
capture the above-mentioned features and thus incorporate users' online
behaviour through statistical aggregates of different features (demography,
temporality, popularity, price). We also show how to capture offer-to-offer
relations, based on their consumption sequence, leveraging neural embeddings
for offers in our Offer2Vec algorithm. We then introduce BoostJet, a novel
recommender which integrates the Trackers along with the neural embeddings
using MatrixNet, an efficient distributed implementation of gradient boosted
decision tree, to improve the recommendation quality significantly. We provide
an in-depth evaluation of BoostJet on Yandex's dataset, collecting online
behaviour from tens of millions of online users, to demonstrate the
practicality of BoostJet in terms of recommendation quality as well as
scalability. | [
1,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Using Big Data to Enhance the Bosch Production Line Performance: A Kaggle Challenge,
Abstract: This paper describes our approach to the Bosch production line performance
challenge run by Kaggle.com. Maximizing the production yield is at the heart of
the manufacturing industry. At the Bosch assembly line, data is recorded for
products as they progress through each stage. Data science methods are applied
to this huge data repository consisting records of tests and measurements made
for each component along the assembly line to predict internal failures. We
found that it is possible to train a model that predicts which parts are most
likely to fail. Thus a smarter failure detection system can be built and the
parts tagged likely to fail can be salvaged to decrease operating costs and
increase the profit margins. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Golden Elliptical Orbits in Newtonian Gravitation,
Abstract: In spherical symmetry with radial coordinate $r$, classical Newtonian
gravitation supports circular orbits and, for $-1/r$ and $r^2$ potentials only,
closed elliptical orbits [1]. Various families of elliptical orbits can be
thought of as arising from the action of perturbations on corresponding
circular orbits. We show that one elliptical orbit in each family is singled
out because its focal length is equal to the radius of the corresponding
unperturbed circular orbit. The eccentricity of this special orbit is related
to the famous irrational number known as the golden ratio. So inanimate
Newtonian gravitation appears to exhibit (but not prefer) the golden ratio
which has been previously identified mostly in settings within the animate
world. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Mathematics"
] |
Title: Towards self-adaptable robots: from programming to training machines,
Abstract: We argue that hardware modularity plays a key role in the convergence of
Robotics and Artificial Intelligence (AI). We introduce a new approach for
building robots that leads to more adaptable and capable machines. We present
the concept of a self-adaptable robot that makes use of hardware modularity and
AI techniques to reduce the effort and time required to be built. We
demonstrate in simulation and with a real robot how, rather than programming,
training produces behaviors in the robot that generalize fast and produce
robust outputs in the presence of noise. In particular, we advocate for
mammals. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science",
"Quantitative Biology"
] |
Title: Incidence Results and Bounds of Trilinear and Quadrilinear Exponential Sums,
Abstract: We give a new bound on the number of collinear triples for two arbitrary
subsets of a finite field. This improves on existing results which rely on the
Cauchy inequality. We then us this to provide a new bound on trilinear and
quadrilinear exponential sums. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Comparison of hidden Markov chain models and hidden Markov random field models in estimation of computed tomography images,
Abstract: There is an interest to replace computed tomography (CT) images with magnetic
resonance (MR) images for a number of diagnostic and therapeutic workflows. In
this article, predicting CT images from a number of magnetic resonance imaging
(MRI) sequences using regression approach is explored. Two principal areas of
application for estimated CT images are dose calculations in MRI-based
radiotherapy treatment planning and attenuation correction for positron
emission tomography (PET)/MRI. The main purpose of this work is to investigate
the performance of hidden Markov (chain) models (HMMs) in comparison to hidden
Markov random field (HMRF) models when predicting CT images of head. Our study
shows that HMMs have clear advantages over HMRF models in this particular
application. Obtained results suggest that HMMs deserve a further study for
investigating their potential in modelling applications where the most natural
theoretical choice would be the class of HMRF models. | [
0,
0,
0,
1,
0,
0
] | [
"Computer Science",
"Statistics"
] |
Title: Spin-charge split pairing in underdoped cuprate superconductors: support from low-$T$ specific heat,
Abstract: We calculate the specific heat of a weakly interacting dilute system of
bosons on a lattice and show that it is consistent with the measured electronic
specific heat in the superconducting state of underdoped cuprates with boson
concentration $\rho \sim x/2$, where $x$ is the hole (dopant) concentration. As
usual, the $T^3$ term is due to Goldstone phonons. The zero-point energy,
through its dependence on the condensate density $\rho_0(T)$, accounts for the
anomalous $T$-linear term. These results support the split-pairing mechanism,
in which spinons (pure spin) are paired at $T^*$ and holons (pure charge) form
real-space pairs at $T_p < T^*$, creating a gauge-coupled physical pair of
charge $+2e$ and concentration $x/2$ which Bose condenses below $T_c$,
accounting for the observed phases. | [
0,
1,
0,
0,
0,
0
] | [
"Physics"
] |
Title: Rethinking probabilistic prediction in the wake of the 2016 U.S. presidential election,
Abstract: To many statisticians and citizens, the outcome of the most recent U.S.
presidential election represents a failure of data-driven methods on the
grandest scale. This impression has led to much debate and discussion about how
the election predictions went awry -- Were the polls inaccurate? Were the
models wrong? Did we misinterpret the probabilities? -- and how they went right
-- Perhaps the analyses were correct even though the predictions were wrong,
that's just the nature of probabilistic forecasting. With this in mind, we
analyze the election outcome with respect to a core set of effectiveness
principles. Regardless of whether and how the election predictions were right
or wrong, we argue that they were ineffective in conveying the extent to which
the data was informative of the outcome and the level of uncertainty in making
these assessments. Among other things, our analysis sheds light on the
shortcomings of the classical interpretations of probability and its
communication to consumers in the form of predictions. We present here an
alternative approach, based on a notion of validity, which offers two immediate
insights for predictive inference. First, the predictions are more
conservative, arguably more realistic, and come with certain guarantees on the
probability of an erroneous prediction. Second, our approach easily and
naturally reflects the (possibly substantial) uncertainty about the model by
outputting plausibilities instead of probabilities. Had these simple steps been
taken by the popular prediction outlets, the election outcome may not have been
so shocking. | [
0,
0,
1,
1,
0,
0
] | [
"Statistics",
"Quantitative Finance"
] |
Title: $L^1$ solutions to one-dimensional BSDEs with sublinear growth generators in $z$,
Abstract: This paper aims at solving a one-dimensional backward stochastic differential
equation (BSDE for short) with only integrable parameters. We first establish
the existence of a minimal $L^1$ solution for the BSDE when the generator $g$
is stronger continuous in $(y,z)$ and monotonic in $y$ as well as it has a
general growth in $y$ and a sublinear growth in $z$. Particularly, the $g$ may
be not uniformly continuous in $z$. Then, we put forward and prove a comparison
theorem and a Levi type theorem on the minimal $L^1$ solutions. A Lebesgue type
theorem on $L^1$ solutions is also obtained. Furthermore, we investigate the
same problem in the case that $g$ may be discontinuous in $y$. Finally, we
prove a general comparison theorem on $L^1$ solutions when $g$ is weakly
monotonic in $y$ and uniformly continuous in $z$ as well as it has a stronger
sublinear growth in $z$. As a byproduct, we also obtain a general existence and
unique theorem on $L^1$ solutions. Our results extend some known works. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Statistics"
] |
Title: Response to "Counterexample to global convergence of DSOS and SDSOS hierarchies",
Abstract: In a recent note [8], the author provides a counterexample to the global
convergence of what his work refers to as "the DSOS and SDSOS hierarchies" for
polynomial optimization problems (POPs) and purports that this refutes claims
in our extended abstract [4] and slides in [3]. The goal of this paper is to
clarify that neither [4], nor [3], and certainly not our full paper [5], ever
defined DSOS or SDSOS hierarchies as it is done in [8]. It goes without saying
that no claims about convergence properties of the hierarchies in [8] were ever
made as a consequence. What was stated in [4,3] was completely different: we
stated that there exist hierarchies based on DSOS and SDSOS optimization that
converge. This is indeed true as we discuss in this response. We also emphasize
that we were well aware that some (S)DSOS hierarchies do not converge even if
their natural SOS counterparts do. This is readily implied by an example in our
prior work [5], which makes the counterexample in [8] superfluous. Finally, we
provide concrete counterarguments to claims made in [8] that aim to challenge
the scalability improvements obtained by DSOS and SDSOS optimization as
compared to sum of squares (SOS) optimization.
[3] A. A. Ahmadi and A. Majumdar. DSOS and SDSOS: More tractable alternatives
to SOS. Slides at the meeting on Geometry and Algebra of Linear Matrix
Inequalities, CIRM, Marseille, 2013. [4] A. A. Ahmadi and A. Majumdar. DSOS and
SDSOS optimization: LP and SOCP-based alternatives to sum of squares
optimization. In proceedings of the 48th annual IEEE Conference on Information
Sciences and Systems, 2014. [5] A. A. Ahmadi and A. Majumdar. DSOS and SDSOS
optimization: more tractable alternatives to sum of squares and semidefinite
optimization. arXiv:1706.02586, 2017. [8] C. Josz. Counterexample to global
convergence of DSOS and SDSOS hierarchies. arXiv:1707.02964, 2017. | [
1,
0,
0,
1,
0,
0
] | [
"Mathematics",
"Computer Science"
] |
Title: Thermal memristor and neuromorphic networks for manipulating heat flow,
Abstract: A memristor is one of four fundamental two-terminal solid elements in
electronics. In addition with the resistor, the capacitor and the inductor,
this passive element relates the electric charges to current in solid state
elements. Here we report the existence of a thermal analog for this element
made with metal-insulator transition materials. We demonstrate that these
memristive systems can be used to create thermal neurons opening so the way to
neuromophic networks for smart thermal management and information treatment. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Computer Science"
] |
Title: Asymptotic Distribution and Simultaneous Confidence Bands for Ratios of Quantile Functions,
Abstract: Ratio of medians or other suitable quantiles of two distributions is widely
used in medical research to compare treatment and control groups or in
economics to compare various economic variables when repeated cross-sectional
data are available. Inspired by the so-called growth incidence curves
introduced in poverty research, we argue that the ratio of quantile functions
is a more appropriate and informative tool to compare two distributions. We
present an estimator for the ratio of quantile functions and develop
corresponding simultaneous confidence bands, which allow to assess significance
of certain features of the quantile functions ratio. Derived simultaneous
confidence bands rely on the asymptotic distribution of the quantile functions
ratio and do not require re-sampling techniques. The performance of the
simultaneous confidence bands is demonstrated in simulations. Analysis of the
expenditure data from Uganda in years 1999, 2002 and 2005 illustrates the
relevance of our approach. | [
0,
0,
0,
1,
0,
0
] | [
"Statistics",
"Mathematics"
] |
Title: A Topological proof that $O_2$ is $2$-MCFL,
Abstract: We give a new proof of Salvati's theorem that the group language $O_2$ is $2$
multiple context free. Unlike Salvati's proof, our arguments do not use any
idea specific to two-dimensions. This raises the possibility that the argument
might generalize to $O_n$. | [
1,
0,
1,
0,
0,
0
] | [
"Mathematics",
"Computer Science"
] |
Title: The Geometry of Strong Koszul Algebras,
Abstract: Koszul algebras with quadratic Groebner bases, called strong Koszul algebras,
are studied. We introduce affine algebraic varieties whose points are in
one-to-one correspondence with certain strong Koszul algebras and we
investigate the connection between the varieties and the algebras. | [
0,
0,
1,
0,
0,
0
] | [
"Mathematics"
] |
Title: Debugging Transactions and Tracking their Provenance with Reenactment,
Abstract: Debugging transactions and understanding their execution are of immense
importance for developing OLAP applications, to trace causes of errors in
production systems, and to audit the operations of a database. However,
debugging transactions is hard for several reasons: 1) after the execution of a
transaction, its input is no longer available for debugging, 2) internal states
of a transaction are typically not accessible, and 3) the execution of a
transaction may be affected by concurrently running transactions. We present a
debugger for transactions that enables non-invasive, post-mortem debugging of
transactions with provenance tracking and supports what-if scenarios (changes
to transaction code or data). Using reenactment, a declarative replay technique
we have developed, a transaction is replayed over the state of the DB seen by
its original execution including all its interactions with concurrently
executed transactions from the history. Importantly, our approach uses the
temporal database and audit logging capabilities available in many DBMS and
does not require any modifications to the underlying database system nor
transactional workload. | [
1,
0,
0,
0,
0,
0
] | [
"Computer Science"
] |
Title: Fast quantum logic gates with trapped-ion qubits,
Abstract: Quantum bits based on individual trapped atomic ions constitute a promising
technology for building a quantum computer, with all the elementary operations
having been achieved with the necessary precision for some error-correction
schemes. However, the essential two-qubit logic gate used for generating
quantum entanglement has hitherto always been performed in an adiabatic regime,
where the gate is slow compared with the characteristic motional frequencies of
ions in the trap, giving logic speeds of order 10kHz. There have been numerous
proposals for performing gates faster than this natural "speed limit" of the
trap. We implement the method of Steane et al., which uses tailored laser
pulses: these are shaped on 10 ns timescales to drive the ions' motion along
trajectories designed such that the gate operation is insensitive to optical
phase fluctuations. This permits fast (MHz-rate) quantum logic which is robust
to this important source of experimental error. We demonstrate entanglement
generation for gate times as short as 480ns; this is less than a single
oscillation period of an ion in the trap, and 8 orders of magnitude shorter
than the memory coherence time measured in similar calcium-43 hyperfine qubits.
The method's power is most evident at intermediate timescales, where it yields
a gate error more than ten times lower than conventional techniques; for
example, we achieve a 1.6 us gate with fidelity 99.8%. Still faster gates are
possible at the price of higher laser intensity. The method requires only a
single amplitude-shaped pulse and one pair of beams derived from a
continuous-wave laser, and offers the prospect of combining the unrivalled
coherence properties, operation fidelities and optical connectivity of
trapped-ion qubits with the sub-microsecond logic speeds usually associated
with solid state devices. | [
0,
1,
0,
0,
0,
0
] | [
"Physics",
"Computer Science"
] |
Title: Non-Asymptotic Rates for Manifold, Tangent Space, and Curvature Estimation,
Abstract: Given an $n$-sample drawn on a submanifold $M \subset \mathbb{R}^D$, we
derive optimal rates for the estimation of tangent spaces $T\_X M$, the second
fundamental form $II\_X^M$, and the submanifold $M$.After motivating their
study, we introduce a quantitative class of $\mathcal{C}^k$-submanifolds in
analogy with H{ö}lder classes.The proposed estimators are based on local
polynomials and allow to deal simultaneously with the three problems at stake.
Minimax lower bounds are derived using a conditional version of Assouad's lemma
when the base point $X$ is random. | [
0,
0,
1,
1,
0,
0
] | [
"Mathematics",
"Statistics"
] |
Subsets and Splits