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arxiv-4501 | 0808.0556 | Logic Engines as Interactors | <|reference_start|>Logic Engines as Interactors: We introduce a new programming language construct, Interactors, supporting the agent-oriented view that programming is a dialog between simple, self-contained, autonomous building blocks. We define Interactors as an abstraction of answer generation and refinement in Logic Engines resulting in expressive language extension and metaprogramming patterns, including emulation of Prolog's dynamic database. A mapping between backtracking based answer generation in the callee and "forward" recursion in the caller enables interaction between different branches of the callee's search process and provides simplified design patterns for algorithms involving combinatorial generation and infinite answer streams. Interactors extend language constructs like Ruby, Python and C#'s multiple coroutining block returns through yield statements and they can emulate the action of monadic constructs and catamorphisms in functional languages. Keywords: generalized iterators, logic engines, agent oriented programming language constructs, interoperation with stateful objects, metaprogramming<|reference_end|> | arxiv | @article{tarau2008logic,
title={Logic Engines as Interactors},
author={Paul Tarau},
journal={arXiv preprint arXiv:0808.0556},
year={2008},
archivePrefix={arXiv},
eprint={0808.0556},
primaryClass={cs.PL cs.MA}
} | tarau2008logic |
arxiv-4502 | 0808.0558 | Communication Through Jamming over a Slotted ALOHA Channel | <|reference_start|>Communication Through Jamming over a Slotted ALOHA Channel: This work derives bounds on the jamming capacity of a slotted ALOHA system. A system with n legitimate users, each with a Bernoulli arrival process is considered. Packets are temporarily stored at the corresponding user queues, and a slotted ALOHA strategy is used for packet transmissions over the shared channel. The scenario considered is that of a pair of illegitimate users that jam legitimate transmissions in order to communicate over the slotted ALOHA channel. Jamming leads to binary signaling between the illegitimate users, with packet collisions due to legitimate users treated as (multiplicative) noise in this channel. Further, the queueing dynamics at the legitimate users stochastically couples the jamming strategy used by the illegitimate users and the channel evolution. By considering various i.i.d. jamming strategies, achievable jamming rates over the slotted ALOHA channel are derived. Further, an upper bound on the jamming capacity over the class of all ergodic jamming policies is derived. These bounds are shown to be tight in the limit where the offered system load approaches unity.<|reference_end|> | arxiv | @article{bhadra2008communication,
title={Communication Through Jamming over a Slotted ALOHA Channel},
author={Sandeep Bhadra, Shreeshankar Bodas, Sanjay Shakkottai, Sriram
Vishwanath},
journal={arXiv preprint arXiv:0808.0558},
year={2008},
archivePrefix={arXiv},
eprint={0808.0558},
primaryClass={cs.IT math.IT}
} | bhadra2008communication |
arxiv-4503 | 0808.0584 | Congestion phenomena on complex networks | <|reference_start|>Congestion phenomena on complex networks: We define a minimal model of traffic flows in complex networks containing the most relevant features of real routing schemes, i.e. a trade--off strategy between topological-based and traffic-based routing. The resulting collective behavior, obtained analytically for the ensemble of uncorrelated networks, is physically very rich and reproduces results recently observed in traffic simulations on scale-free networks. We find that traffic control is useless in homogeneous graphs but may improves global performance in inhomogeneous networks, enlarging the free-flow region in parameter space. Traffic control also introduces non-linear effects and, beyond a critical strength, may trigger the appearance of a congested phase in a discontinuous manner.<|reference_end|> | arxiv | @article{de martino2008congestion,
title={Congestion phenomena on complex networks},
author={Daniele De Martino, Luca Dall'Asta, Ginestra Bianconi and Matteo
Marsili},
journal={arXiv preprint arXiv:0808.0584},
year={2008},
doi={10.1103/PhysRevE.79.015101},
archivePrefix={arXiv},
eprint={0808.0584},
primaryClass={physics.soc-ph cs.NI}
} | de martino2008congestion |
arxiv-4504 | 0808.0586 | Coinductive big-step operational semantics | <|reference_start|>Coinductive big-step operational semantics: Using a call-by-value functional language as an example, this article illustrates the use of coinductive definitions and proofs in big-step operational semantics, enabling it to describe diverging evaluations in addition to terminating evaluations. We formalize the connections between the coinductive big-step semantics and the standard small-step semantics, proving that both semantics are equivalent. We then study the use of coinductive big-step semantics in proofs of type soundness and proofs of semantic preservation for compilers. A methodological originality of this paper is that all results have been proved using the Coq proof assistant. We explain the proof-theoretic presentation of coinductive definitions and proofs offered by Coq, and show that it facilitates the discovery and the presentation of the results.<|reference_end|> | arxiv | @article{leroy2008coinductive,
title={Coinductive big-step operational semantics},
author={Xavier Leroy (INRIA Rocquencourt), Herv'e Grall (INRIA Rennes, LINA)},
journal={Information and Computation (2007)},
year={2008},
archivePrefix={arXiv},
eprint={0808.0586},
primaryClass={cs.PL}
} | leroy2008coinductive |
arxiv-4505 | 0808.0596 | On row-by-row coding for 2-D constraints | <|reference_start|>On row-by-row coding for 2-D constraints: A constant-rate encoder--decoder pair is presented for a fairly large family of two-dimensional (2-D) constraints. Encoding and decoding is done in a row-by-row manner, and is sliding-block decodable. Essentially, the 2-D constraint is turned into a set of independent and relatively simple one-dimensional (1-D) constraints; this is done by dividing the array into fixed-width vertical strips. Each row in the strip is seen as a symbol, and a graph presentation of the respective 1-D constraint is constructed. The maxentropic stationary Markov chain on this graph is next considered: a perturbed version of the corresponding probability distribution on the edges of the graph is used in order to build an encoder which operates in parallel on the strips. This perturbation is found by means of a network flow, with upper and lower bounds on the flow through the edges. A key part of the encoder is an enumerative coder for constant-weight binary words. A fast realization of this coder is shown, using floating-point arithmetic.<|reference_end|> | arxiv | @article{tal2008on,
title={On row-by-row coding for 2-D constraints},
author={Ido Tal, Tuvi Etzion, Ron M. Roth},
journal={arXiv preprint arXiv:0808.0596},
year={2008},
archivePrefix={arXiv},
eprint={0808.0596},
primaryClass={cs.IT math.IT}
} | tal2008on |
arxiv-4506 | 0808.0634 | Reducing Protocol Analysis with XOR to the XOR-free Case in the Horn Theory Based Approach | <|reference_start|>Reducing Protocol Analysis with XOR to the XOR-free Case in the Horn Theory Based Approach: In the Horn theory based approach for cryptographic protocol analysis, cryptographic protocols and (Dolev-Yao) intruders are modeled by Horn theories and security analysis boils down to solving the derivation problem for Horn theories. This approach and the tools based on this approach, including ProVerif, have been very successful in the automatic analysis of cryptographic protocols w.r.t. an unbounded number of sessions. However, dealing with the algebraic properties of operators such as the exclusive OR (XOR) has been problematic. In particular, ProVerif cannot deal with XOR. In this paper, we show how to reduce the derivation problem for Horn theories with XOR to the XOR-free case. Our reduction works for an expressive class of Horn theories. A large class of intruder capabilities and protocols that employ the XOR operator can be modeled by these theories. Our reduction allows us to carry out protocol analysis by tools, such as ProVerif, that cannot deal with XOR, but are very efficient in the XOR-free case. We implemented our reduction and, in combination with ProVerif, applied it in the automatic analysis of several protocols that use the XOR operator. In one case, we found a new attack.<|reference_end|> | arxiv | @article{kuesters2008reducing,
title={Reducing Protocol Analysis with XOR to the XOR-free Case in the Horn
Theory Based Approach},
author={Ralf Kuesters and Tomasz Truderung},
journal={arXiv preprint arXiv:0808.0634},
year={2008},
archivePrefix={arXiv},
eprint={0808.0634},
primaryClass={cs.CR}
} | kuesters2008reducing |
arxiv-4507 | 0808.0647 | Model Checking Positive Equality-free FO: Boolean Structures and Digraphs of Size Three | <|reference_start|>Model Checking Positive Equality-free FO: Boolean Structures and Digraphs of Size Three: We study the model checking problem, for fixed structures A, over positive equality-free first-order logic -- a natural generalisation of the non-uniform quantified constraint satisfaction problem QCSP(A). We prove a complete complexity classification for this problem when A ranges over 1.) boolean structures and 2.) digraphs of size (less than or equal to) three. The former class displays dichotomy between Logspace and Pspace-complete, while the latter class displays tetrachotomy between Logspace, NP-complete, co-NP-complete and Pspace-complete.<|reference_end|> | arxiv | @article{martin2008model,
title={Model Checking Positive Equality-free FO: Boolean Structures and
Digraphs of Size Three},
author={Barnaby Martin},
journal={arXiv preprint arXiv:0808.0647},
year={2008},
archivePrefix={arXiv},
eprint={0808.0647},
primaryClass={cs.CC cs.LO}
} | martin2008model |
arxiv-4508 | 0808.0665 | Weighted distance transforms generalized to modules and their computation on point lattices | <|reference_start|>Weighted distance transforms generalized to modules and their computation on point lattices: This paper presents the generalization of weighted distances to modules and their computation through the chamfer algorithm on general point lattices. The first part is dedicated to formalization of definitions and properties (distance, metric, norm) of weighted distances on modules. It resumes tools found in literature to express the weighted distance of any point of a module and to compute optimal weights in the general case to get rotation invariant distances. The second part of this paper proves that, for any point lattice, the sequential two-scan chamfer algorithm produces correct distance maps. Finally, the definitions and computation of weighted distances are applied to the face-centered cubic (FCC) and body-centered cubic (BCC) grids.<|reference_end|> | arxiv | @article{fouard2008weighted,
title={Weighted distance transforms generalized to modules and their
computation on point lattices},
author={C'eline Fouard (INRIA Sophia Antipolis), Robin Strand (CBA), Gunilla
Borgefors (CBA)},
journal={Pattern Recognition 40, 9 (2007) 2453--2474},
year={2008},
doi={10.1016/j.patcog.2007.01.001},
archivePrefix={arXiv},
eprint={0808.0665},
primaryClass={cs.DM}
} | fouard2008weighted |
arxiv-4509 | 0808.0684 | 9-variable Boolean Functions with Nonlinearity 242 in the Generalized Rotation Class | <|reference_start|>9-variable Boolean Functions with Nonlinearity 242 in the Generalized Rotation Class: In 2006, 9-variable Boolean functions having nonlinearity 241, which is strictly greater than the bent concatenation bound of 240, have been discovered in the class of Rotation Symmetric Boolean Functions (RSBFs) by Kavut, Maitra and Yucel. To improve this nonlinearity result, we have firstly defined some subsets of the n-variable Boolean functions as the "generalized classes of k-RSBFs and k-DSBFs (k-Dihedral Symmetric Boolean Functions)", where k is a positive integer dividing n and k-RSBFs is a subset of l-RSBFs if k < l. Secondly, utilizing the steepest-descent like iterative heuristic search algorithm used previously to identify the 9-variable RSBFs with nonlinearity 241, we have made a search within the classes of 3-RSBFs and 3-DSBFs. The search has accomplished to find 9-variable Boolean functions with nonlinearity 242 in both of these classes. It should be emphasized that although the class of 3-RSBFs contains functions with nonlinearity 242; 1-RSBFs or simply RSBFs, which is a subset of 3-RSBFs, does not contain any. This result also shows that the covering radius of the first order Reed-Muller code R(1, 9) is at least equal to 242. Thirdly, motivated by the fact that RSBFs are invariant under a special permutation of the input vector, we have classified all possible permutations up to the linear equivalence of Boolean functions that are invariant under those permutations. Specifically, for 9-variable Boolean functions, 9! possible permutations are classified into 30 classes; and the search algorithm identifies some of these classes as "rich". The rich classes yield new Boolean functions with nonlinearity 242 having different autocorrelation spectra from those of the functions found in the generalized 3-RSBF and 3-DSBF classes.<|reference_end|> | arxiv | @article{kavut20089-variable,
title={9-variable Boolean Functions with Nonlinearity 242 in the Generalized
Rotation Class},
author={Selcuk Kavut and Melek Diker Yucel},
journal={arXiv preprint arXiv:0808.0684},
year={2008},
archivePrefix={arXiv},
eprint={0808.0684},
primaryClass={cs.CR cs.IT math.IT}
} | kavut20089-variable |
arxiv-4510 | 0808.0732 | Dynamics, robustness and fragility of trust | <|reference_start|>Dynamics, robustness and fragility of trust: Trust is often conveyed through delegation, or through recommendation. This makes the trust authorities, who process and publish trust recommendations, into an attractive target for attacks and spoofing. In some recent empiric studies, this was shown to lead to a remarkable phenomenon of *adverse selection*: a greater percentage of unreliable or malicious web merchants were found among those with certain types of trust certificates, then among those without. While such findings can be attributed to a lack of diligence in trust authorities, or even to conflicts of interest, our analysis of trust dynamics suggests that public trust networks would probably remain vulnerable even if trust authorities were perfectly diligent. The reason is that the process of trust building, if trust is not breached too often, naturally leads to power-law distributions: the rich get richer, the trusted attract more trust. The evolutionary processes with such distributions, ubiquitous in nature, are known to be robust with respect to random failures, but vulnerable to adaptive attacks. We recommend some ways to decrease the vulnerability of trust building, and suggest some ideas for exploration.<|reference_end|> | arxiv | @article{pavlovic2008dynamics,,
title={Dynamics, robustness and fragility of trust},
author={Dusko Pavlovic},
journal={arXiv preprint arXiv:0808.0732},
year={2008},
archivePrefix={arXiv},
eprint={0808.0732},
primaryClass={cs.CR}
} | pavlovic2008dynamics, |
arxiv-4511 | 0808.0745 | Relay-Assisted User Scheduling in Wireless Networks with Hybrid-ARQ | <|reference_start|>Relay-Assisted User Scheduling in Wireless Networks with Hybrid-ARQ: This paper studies the problem of relay-assisted user scheduling for downlink wireless transmission. The base station or access point employs hybrid automatic-repeat-request (HARQ) with the assistance of a set of fixed relays to serve a set of mobile users. By minimizing a cost function of the queue lengths at the base station and the number of retransmissions of the head-of-line packet for each user, the base station can schedule an appropriate user in each time slot and an appropriate transmitter to serve it. It is shown that a priority-index policy is optimal for a linear cost function with packets arriving according to a Poisson process and for an increasing convex cost function where packets must be drained from the queues at the base station.<|reference_end|> | arxiv | @article{lo2008relay-assisted,
title={Relay-Assisted User Scheduling in Wireless Networks with Hybrid-ARQ},
author={Caleb K. Lo, John J. Hasenbein, Sriram Vishwanath and Robert W. Heath
Jr},
journal={arXiv preprint arXiv:0808.0745},
year={2008},
doi={10.1109/TVT.2009.2027711},
archivePrefix={arXiv},
eprint={0808.0745},
primaryClass={cs.IT math.IT}
} | lo2008relay-assisted |
arxiv-4512 | 0808.0753 | Ranking Catamorphisms and Unranking Anamorphisms on Hereditarily Finite Datatypes | <|reference_start|>Ranking Catamorphisms and Unranking Anamorphisms on Hereditarily Finite Datatypes: Using specializations of unfold and fold on a generic tree data type we derive unranking and ranking functions providing natural number encodings for various Hereditarily Finite datatypes. In this context, we interpret unranking operations as instances of a generic anamorphism and ranking operations as instances of the corresponding catamorphism. Starting with Ackerman's Encoding from Hereditarily Finite Sets to Natural Numbers we define pairings and tuple encodings that provide building blocks for a theory of Hereditarily Finite Functions. The more difficult problem of ranking and unranking Hereditarily Finite Permutations is then tackled using Lehmer codes and factoradics. The self-contained source code of the paper, as generated from a literate Haskell program, is available at \url{http://logic.csci.unt.edu/tarau/research/2008/fFUN.zip}. Keywords: ranking/unranking, pairing/tupling functions, Ackermann encoding, hereditarily finite sets, hereditarily finite functions, permutations and factoradics, computational mathematics, Haskell data representations<|reference_end|> | arxiv | @article{tarau2008ranking,
title={Ranking Catamorphisms and Unranking Anamorphisms on Hereditarily Finite
Datatypes},
author={Paul Tarau},
journal={arXiv preprint arXiv:0808.0753},
year={2008},
archivePrefix={arXiv},
eprint={0808.0753},
primaryClass={cs.SC cs.DM cs.DS}
} | tarau2008ranking |
arxiv-4513 | 0808.0754 | A Functional Hitchhiker's Guide to Hereditarily Finite Sets, Ackermann Encodings and Pairing Functions | <|reference_start|>A Functional Hitchhiker's Guide to Hereditarily Finite Sets, Ackermann Encodings and Pairing Functions: The paper is organized as a self-contained literate Haskell program that implements elements of an executable finite set theory with focus on combinatorial generation and arithmetic encodings. The code, tested under GHC 6.6.1, is available at http://logic.csci.unt.edu/tarau/research/2008/fSET.zip . We introduce ranking and unranking functions generalizing Ackermann's encoding to the universe of Hereditarily Finite Sets with Urelements. Then we build a lazy enumerator for Hereditarily Finite Sets with Urelements that matches the unranking function provided by the inverse of Ackermann's encoding and we describe functors between them resulting in arithmetic encodings for powersets, hypergraphs, ordinals and choice functions. After implementing a digraph representation of Hereditarily Finite Sets we define {\em decoration functions} that can recover well-founded sets from encodings of their associated acyclic digraphs. We conclude with an encoding of arbitrary digraphs and discuss a concept of duality induced by the set membership relation. Keywords: hereditarily finite sets, ranking and unranking functions, executable set theory, arithmetic encodings, Haskell data representations, functional programming and computational mathematics<|reference_end|> | arxiv | @article{tarau2008a,
title={A Functional Hitchhiker's Guide to Hereditarily Finite Sets, Ackermann
Encodings and Pairing Functions},
author={Paul Tarau},
journal={arXiv preprint arXiv:0808.0754},
year={2008},
archivePrefix={arXiv},
eprint={0808.0754},
primaryClass={cs.MS cs.DM cs.DS}
} | tarau2008a |
arxiv-4514 | 0808.0760 | Declarative Combinatorics: Boolean Functions, Circuit Synthesis and BDDs in Haskell | <|reference_start|>Declarative Combinatorics: Boolean Functions, Circuit Synthesis and BDDs in Haskell: We describe Haskell implementations of interesting combinatorial generation algorithms with focus on boolean functions and logic circuit representations. First, a complete exact combinational logic circuit synthesizer is described as a combination of catamorphisms and anamorphisms. Using pairing and unpairing functions on natural number representations of truth tables, we derive an encoding for Binary Decision Diagrams (BDDs) with the unique property that its boolean evaluation faithfully mimics its structural conversion to a a natural number through recursive application of a matching pairing function. We then use this result to derive ranking and unranking functions for BDDs and reduced BDDs. Finally, a generalization of the encoding techniques to Multi-Terminal BDDs is provided. The paper is organized as a self-contained literate Haskell program, available at http://logic.csci.unt.edu/tarau/research/2008/fBDD.zip . Keywords: exact combinational logic synthesis, binary decision diagrams, encodings of boolean functions, pairing/unpairing functions, ranking/unranking functions for BDDs and MTBDDs, declarative combinatorics in Haskell<|reference_end|> | arxiv | @article{tarau2008declarative,
title={Declarative Combinatorics: Boolean Functions, Circuit Synthesis and BDDs
in Haskell},
author={Paul Tarau},
journal={arXiv preprint arXiv:0808.0760},
year={2008},
archivePrefix={arXiv},
eprint={0808.0760},
primaryClass={cs.DS}
} | tarau2008declarative |
arxiv-4515 | 0808.0768 | Foundations of Information Theory | <|reference_start|>Foundations of Information Theory: Information is the basic concept of information theory. However, there is no definition of this concept that can encompass all uses of the term information in information theories and beyond. Many question a possibility of such a definition. However, foundations of information theory developed in the context of the general theory of information made it possible to build such a relevant and at the same time, encompassing definition. Foundations of information theory are built in a form of ontological principles, which reflect basic features of information and information processes.<|reference_end|> | arxiv | @article{burgin2008foundations,
title={Foundations of Information Theory},
author={Mark Burgin},
journal={arXiv preprint arXiv:0808.0768},
year={2008},
archivePrefix={arXiv},
eprint={0808.0768},
primaryClass={cs.IT math.IT}
} | burgin2008foundations |
arxiv-4516 | 0808.0845 | Mutual information is copula entropy | <|reference_start|>Mutual information is copula entropy: We prove that mutual information is actually negative copula entropy, based on which a method for mutual information estimation is proposed.<|reference_end|> | arxiv | @article{ma2008mutual,
title={Mutual information is copula entropy},
author={Jian Ma and Zengqi Sun},
journal={arXiv preprint arXiv:0808.0845},
year={2008},
archivePrefix={arXiv},
eprint={0808.0845},
primaryClass={cs.IT cs.LG math.IT math.ST stat.TH}
} | ma2008mutual |
arxiv-4517 | 0808.0876 | Capacity Regions and Bounds for a Class of Z-interference Channels | <|reference_start|>Capacity Regions and Bounds for a Class of Z-interference Channels: We define a class of Z-interference channels for which we obtain a new upper bound on the capacity region. The bound exploits a technique first introduced by Korner and Marton. A channel in this class has the property that, for the transmitter-receiver pair that suffers from interference, the conditional output entropy at the receiver is invariant with respect to the transmitted codewords. We compare the new capacity region upper bound with the Han/Kobayashi achievable rate region for interference channels. This comparison shows that our bound is tight in some cases, thereby yielding specific points on the capacity region as well as sum capacity for certain Z-interference channels. In particular, this result can be used as an alternate method to obtain sum capacity of Gaussian Z-interference channels. We then apply an additional restriction on our channel class: the transmitter-receiver pair that suffers from interference achieves its maximum output entropy with a single input distribution irrespective of the interference distribution. For these channels we show that our new capacity region upper bound coincides with the Han/Kobayashi achievable rate region, which is therefore capacity-achieving. In particular, for these channels superposition encoding with partial decoding is shown to be optimal and a single-letter characterization for the capacity region is obtained.<|reference_end|> | arxiv | @article{liu2008capacity,
title={Capacity Regions and Bounds for a Class of Z-interference Channels},
author={Nan Liu and Andrea Goldsmith},
journal={arXiv preprint arXiv:0808.0876},
year={2008},
archivePrefix={arXiv},
eprint={0808.0876},
primaryClass={cs.IT math.IT}
} | liu2008capacity |
arxiv-4518 | 0808.0920 | A Distributed and Deterministic TDMA Algorithm for Write-All-With-Collision Model | <|reference_start|>A Distributed and Deterministic TDMA Algorithm for Write-All-With-Collision Model: Several self-stabilizing time division multiple access (TDMA) algorithms are proposed for sensor networks. In addition to providing a collision-free communication service, such algorithms enable the transformation of programs written in abstract models considered in distributed computing literature into a model consistent with sensor networks, i.e., write all with collision (WAC) model. Existing TDMA slot assignment algorithms have one or more of the following properties: (i) compute slots using a randomized algorithm, (ii) assume that the topology is known upfront, and/or (iii) assign slots sequentially. If these algorithms are used to transform abstract programs into programs in WAC model then the transformed programs are probabilistically correct, do not allow the addition of new nodes, and/or converge in a sequential fashion. In this paper, we propose a self-stabilizing deterministic TDMA algorithm where a sensor is aware of only its neighbors. We show that the slots are assigned to the sensors in a concurrent fashion and starting from arbitrary initial states, the algorithm converges to states where collision-free communication among the sensors is restored. Moreover, this algorithm facilitates the transformation of abstract programs into programs in WAC model that are deterministically correct.<|reference_end|> | arxiv | @article{arumugam2008a,
title={A Distributed and Deterministic TDMA Algorithm for
Write-All-With-Collision Model},
author={Mahesh Arumugam},
journal={arXiv preprint arXiv:0808.0920},
year={2008},
archivePrefix={arXiv},
eprint={0808.0920},
primaryClass={cs.OS cs.DC}
} | arumugam2008a |
arxiv-4519 | 0808.0948 | Capacity of a Class of Diamond Channels | <|reference_start|>Capacity of a Class of Diamond Channels: We study a special class of diamond channels which was introduced by Schein in 2001. In this special class, each diamond channel consists of a transmitter, a noisy relay, a noiseless relay and a receiver. We prove the capacity of this class of diamond channels by providing an achievable scheme and a converse. The capacity we show is strictly smaller than the cut-set bound. Our result also shows the optimality of a combination of decode-and-forward (DAF) and compress-and-forward (CAF) at the noisy relay node. This is the first example where a combination of DAF and CAF is shown to be capacity achieving. Finally, we note that there exists a duality between this diamond channel coding problem and the Kaspi-Berger source coding problem.<|reference_end|> | arxiv | @article{kang2008capacity,
title={Capacity of a Class of Diamond Channels},
author={Wei Kang, Sennur Ulukus},
journal={arXiv preprint arXiv:0808.0948},
year={2008},
archivePrefix={arXiv},
eprint={0808.0948},
primaryClass={cs.IT math.IT}
} | kang2008capacity |
arxiv-4520 | 0808.0954 | Achievable rate regions for bi-directional relaying | <|reference_start|>Achievable rate regions for bi-directional relaying: In a bi-directional relay channel, two nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of a relay. In this paper, we derive achievable rate regions for four new half-duplex protocols and compare these to four existing half-duplex protocols and outer bounds. In time, our protocols consist of either two or three phases. In the two phase protocols, both users simultaneously transmit during the first phase and the relay alone transmits during the second phase, while in the three phase protocol the two users sequentially transmit followed by a transmission from the relay. The relay may forward information in one of four manners; we outline existing Amplify and Forward (AF), Decode and Forward (DF) and Compress and Forward (CF) relaying schemes and introduce the novel Mixed Forward scheme. The latter is a combination of CF in one direction and DF in the other. We derive achievable rate regions for the CF and Mixed relaying schemes for the two and three phase protocols. In the last part of this work we provide a comprehensive treatment of 8 possible half-duplex bi-directional relaying protocols in Gaussian noise, obtaining their respective achievable rate regions, outer bounds, and their relative performance under different SNR and relay geometries.<|reference_end|> | arxiv | @article{kim2008achievable,
title={Achievable rate regions for bi-directional relaying},
author={Sang Joon Kim, Natasha Devroye, Patrick Mitran, Vahid Tarokh},
journal={arXiv preprint arXiv:0808.0954},
year={2008},
archivePrefix={arXiv},
eprint={0808.0954},
primaryClass={cs.IT math.IT}
} | kim2008achievable |
arxiv-4521 | 0808.0962 | Verification of Peterson's Algorithm for Leader Election in a Unidirectional Asynchronous Ring Using NuSMV | <|reference_start|>Verification of Peterson's Algorithm for Leader Election in a Unidirectional Asynchronous Ring Using NuSMV: The finite intrinsic nature of the most distributed algorithms gives us this ability to use model checking tools for verification of this type of algorithms. In this paper, I attempt to use NuSMV as a model checking tool for verifying necessary properties of Peterson's algorithm for leader election problem in a unidirectional asynchronous ring topology. Peterson's algorithm for an asynchronous ring supposes that each node in the ring has a unique ID and also a queue for dealing with storage problem. By considering that the queue can have any combination of values, a constructed model for a ring with only four nodes will have more than a billion states. Although it seems that model checking is not a feasible approach for this problem, I attempt to use several effective limiting assumptions for hiring formal model checking approach without losing the correct functionality of the Peterson's algorithm. These enforced limiting assumptions target the degree of freedom in the model checking process and significantly decrease the CPU time, memory usage and the total number of page faults. By deploying these limitations, the number of nodes can be increased from four to eight in the model checking process with NuSMV.<|reference_end|> | arxiv | @article{ansari2008verification,
title={Verification of Peterson's Algorithm for Leader Election in a
Unidirectional Asynchronous Ring Using NuSMV},
author={Amin Ansari},
journal={arXiv preprint arXiv:0808.0962},
year={2008},
archivePrefix={arXiv},
eprint={0808.0962},
primaryClass={cs.LO cs.DC}
} | ansari2008verification |
arxiv-4522 | 0808.0973 | Text Modeling using Unsupervised Topic Models and Concept Hierarchies | <|reference_start|>Text Modeling using Unsupervised Topic Models and Concept Hierarchies: Statistical topic models provide a general data-driven framework for automated discovery of high-level knowledge from large collections of text documents. While topic models can potentially discover a broad range of themes in a data set, the interpretability of the learned topics is not always ideal. Human-defined concepts, on the other hand, tend to be semantically richer due to careful selection of words to define concepts but they tend not to cover the themes in a data set exhaustively. In this paper, we propose a probabilistic framework to combine a hierarchy of human-defined semantic concepts with statistical topic models to seek the best of both worlds. Experimental results using two different sources of concept hierarchies and two collections of text documents indicate that this combination leads to systematic improvements in the quality of the associated language models as well as enabling new techniques for inferring and visualizing the semantics of a document.<|reference_end|> | arxiv | @article{chemudugunta2008text,
title={Text Modeling using Unsupervised Topic Models and Concept Hierarchies},
author={Chaitanya Chemudugunta, Padhraic Smyth and Mark Steyvers},
journal={arXiv preprint arXiv:0808.0973},
year={2008},
archivePrefix={arXiv},
eprint={0808.0973},
primaryClass={cs.AI cs.IR}
} | chemudugunta2008text |
arxiv-4523 | 0808.0978 | Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace Projections | <|reference_start|>Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace Projections: Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace Projections<|reference_end|> | arxiv | @article{scutari2008cognitive,
title={Cognitive MIMO Radio: A Competitive Optimality Design Based on Subspace
Projections},
author={Gesualdo Scutari, Daniel P. Palomar, Sergio Barbarossa},
journal={IEEE Signal Processing Magazine Special Issue on Signal Processing
for Cognitive Radio Networks, November 2008},
year={2008},
doi={10.1109/MSP.2008.929297},
archivePrefix={arXiv},
eprint={0808.0978},
primaryClass={cs.IT cs.GT math.IT}
} | scutari2008cognitive |
arxiv-4524 | 0808.0980 | On Complexity of Minimum Leaf Out-branching Problem | <|reference_start|>On Complexity of Minimum Leaf Out-branching Problem: Given a digraph $D$, the Minimum Leaf Out-Branching problem (MinLOB) is the problem of finding in $D$ an out-branching with the minimum possible number of leaves, i.e., vertices of out-degree 0. Gutin, Razgon and Kim (2008) proved that MinLOB is polynomial time solvable for acyclic digraphs which are exactly the digraphs of directed path-width (DAG-width, directed tree-width, respectively) 0. We investigate how much one can extend this polynomiality result. We prove that already for digraphs of directed path-width (directed tree-width, DAG-width, respectively) 1, MinLOB is NP-hard. On the other hand, we show that for digraphs of restricted directed tree-width (directed path-width, DAG-width, respectively) and a fixed integer $k$, the problem of checking whether there is an out-branching with at most $k$ leaves is polynomial time solvable.<|reference_end|> | arxiv | @article{dankelmann2008on,
title={On Complexity of Minimum Leaf Out-branching Problem},
author={Peter Dankelmann, Gregory Gutin, Eun Jung Kim},
journal={arXiv preprint arXiv:0808.0980},
year={2008},
archivePrefix={arXiv},
eprint={0808.0980},
primaryClass={cs.DS cs.CC}
} | dankelmann2008on |
arxiv-4525 | 0808.0987 | A new graph perspective on max-min fairness in Gaussian parallel channels | <|reference_start|>A new graph perspective on max-min fairness in Gaussian parallel channels: In this work we are concerned with the problem of achieving max-min fairness in Gaussian parallel channels with respect to a general performance function, including channel capacity or decoding reliability as special cases. As our central results, we characterize the laws which determine the value of the achievable max-min fair performance as a function of channel sharing policy and power allocation (to channels and users). In particular, we show that the max-min fair performance behaves as a specialized version of the Lovasz function, or Delsarte bound, of a certain graph induced by channel sharing combinatorics. We also prove that, in addition to such graph, merely a certain 2-norm distance dependent on the allowable power allocations and used performance functions, is sufficient for the characterization of max-min fair performance up to some candidate interval. Our results show also a specific role played by odd cycles in the graph induced by the channel sharing policy and we present an interesting relation between max-min fairness in parallel channels and optimal throughput in an associated interference channel.<|reference_end|> | arxiv | @article{wiczanowski2008a,
title={A new graph perspective on max-min fairness in Gaussian parallel
channels},
author={Marcin Wiczanowski, Holger Boche},
journal={arXiv preprint arXiv:0808.0987},
year={2008},
doi={10.1109/ISITA.2008.4895521},
archivePrefix={arXiv},
eprint={0808.0987},
primaryClass={cs.IT cs.DM math.CO math.IT}
} | wiczanowski2008a |
arxiv-4526 | 0808.1000 | Fitness Landscape Analysis for Dynamic Resource Allocation in Multiuser OFDM Based Cognitive Radio Systems | <|reference_start|>Fitness Landscape Analysis for Dynamic Resource Allocation in Multiuser OFDM Based Cognitive Radio Systems: This paper has been withdrawn.<|reference_end|> | arxiv | @article{huang2008fitness,
title={Fitness Landscape Analysis for Dynamic Resource Allocation in Multiuser
OFDM Based Cognitive Radio Systems},
author={Dong Huang, Chunyan Miao, Cyril Leung},
journal={arXiv preprint arXiv:0808.1000},
year={2008},
archivePrefix={arXiv},
eprint={0808.1000},
primaryClass={cs.IT cs.NE math.CO math.IT}
} | huang2008fitness |
arxiv-4527 | 0808.1007 | On Quantum Capacity of Compound Channels | <|reference_start|>On Quantum Capacity of Compound Channels: In this paper we address the issue of universal or robust communication over quantum channels. Specifically, we consider memoryless communication scenario with channel uncertainty which is an analog of compound channel in classical information theory. We determine the quantum capacity of finite compound channels and arbitrary compound channels with informed decoder. Our approach in the finite case is based on the observation that perfect channel knowledge at the decoder does not increase the capacity of finite quantum compound channels. As a consequence we obtain coding theorem for finite quantum averaged channels, the simplest class of channels with long-term memory. The extension of these results to quantum compound channels with uninformed encoder and decoder, and infinitely many constituents remains an open problem.<|reference_end|> | arxiv | @article{bjelakovic2008on,
title={On Quantum Capacity of Compound Channels},
author={I. Bjelakovic, H. Boche, J. Noetzel},
journal={arXiv preprint arXiv:0808.1007},
year={2008},
doi={10.1103/PhysRevA.78.042331},
archivePrefix={arXiv},
eprint={0808.1007},
primaryClass={quant-ph cs.IT math-ph math.IT math.MP}
} | bjelakovic2008on |
arxiv-4528 | 0808.1062 | Optimization of Location Management for PCS Networks with CTRW Mobility Model | <|reference_start|>Optimization of Location Management for PCS Networks with CTRW Mobility Model: This paper considers the design of the optimal locationupdate area (LA) of the distance-based scheme for personal communication service (PCS) networks. We focus on the optimization of two design parameters associated with the LA: 1) initial position upon LA update; 2) distance threshold for triggering of LA update. Based on the popular continuous-time random walk (CTRW) mobility model, we propose a novel analytical framework that uses a diffusion equation to minimize the location management cost. In this framework, a number of measurable physical parameters, such as length of road section, angle between road sections, and road section crossing time, can be integrated into the system design. This framework allows us to easily evaluate the total cost under general call arrival distributions and LA of different shapes. For the particular case of circular LA and small Poisson call-arrival rate, we prove the following: (1) When the drift is weak, the optimal initial position approaches the center of the LA; when the drift is strong, it approaches the boundary of the LA. (2) Comparing the optimal initial-position and center-initial-position solutions (which is assumed in most prior work), when the drift is weak, the optimal distance threshold and the minimum total cost are roughly equal; when the drift is strong, the optimal distance threshold in the later is about 1.260 times that in the former, and the minimum total cost in the later is about 1.587 times that in the former. That is, optimizing on initial position, which previous work did not consider, has the potential of reducing the cost measure by 37%.<|reference_end|> | arxiv | @article{zhao2008optimization,
title={Optimization of Location Management for PCS Networks with CTRW Mobility
Model},
author={Qinglin Zhao, Soung C. Liew},
journal={arXiv preprint arXiv:0808.1062},
year={2008},
archivePrefix={arXiv},
eprint={0808.1062},
primaryClass={cs.NI cs.PF}
} | zhao2008optimization |
arxiv-4529 | 0808.1108 | Cache oblivious storage and access heuristics for blocked matrix-matrix multiplication | <|reference_start|>Cache oblivious storage and access heuristics for blocked matrix-matrix multiplication: We investigate effects of ordering in blocked matrix--matrix multiplication. We find that submatrices do not have to be stored contiguously in memory to achieve near optimal performance. Instead it is the choice of execution order of the submatrix multiplications that leads to a speedup of up to four times for small block sizes. This is in contrast to results for single matrix elements showing that contiguous memory allocation quickly becomes irrelevant as the blocksize increases.<|reference_end|> | arxiv | @article{bock2008cache,
title={Cache oblivious storage and access heuristics for blocked matrix-matrix
multiplication},
author={Nicolas Bock and Emanuel H. Rubensson and Pawe{l} Sa{l}ek and Anders
M. N. Niklasson and Matt Challacombe},
journal={arXiv preprint arXiv:0808.1108},
year={2008},
archivePrefix={arXiv},
eprint={0808.1108},
primaryClass={cs.DS}
} | bock2008cache |
arxiv-4530 | 0808.1119 | Graham's Schedules and the Number Partition Problem | <|reference_start|>Graham's Schedules and the Number Partition Problem: We show the equivalence of the Number Partition Problem and the two processor scheduling problem. We establish a priori bounds on the completion times for the scheduling problem which are tighter than Graham's but almost on par with a posteriori bounds of Coffman and Sethi. We conclude the paper with a characterization of the asymptotic behavior of the scheduling problem which relates to the spread of the processing times and the number of jobs.<|reference_end|> | arxiv | @article{reddi2008graham's,
title={Graham's Schedules and the Number Partition Problem},
author={Seenu S. Reddi},
journal={arXiv preprint arXiv:0808.1119},
year={2008},
archivePrefix={arXiv},
eprint={0808.1119},
primaryClass={cs.CC cs.DM}
} | reddi2008graham's |
arxiv-4531 | 0808.1125 | Verified Null-Move Pruning | <|reference_start|>Verified Null-Move Pruning: In this article we review standard null-move pruning and introduce our extended version of it, which we call verified null-move pruning. In verified null-move pruning, whenever the shallow null-move search indicates a fail-high, instead of cutting off the search from the current node, the search is continued with reduced depth. Our experiments with verified null-move pruning show that on average, it constructs a smaller search tree with greater tactical strength in comparison to standard null-move pruning. Moreover, unlike standard null-move pruning, which fails badly in zugzwang positions, verified null-move pruning manages to detect most zugzwangs and in such cases conducts a re-search to obtain the correct result. In addition, verified null-move pruning is very easy to implement, and any standard null-move pruning program can use verified null-move pruning by modifying only a few lines of code.<|reference_end|> | arxiv | @article{david-tabibi2008verified,
title={Verified Null-Move Pruning},
author={Omid David-Tabibi and Nathan S. Netanyahu},
journal={ICGA Journal, International Computer Games Association, Vol. 25,
No. 3, pp. 153--161, September 2002},
year={2008},
archivePrefix={arXiv},
eprint={0808.1125},
primaryClass={cs.AI}
} | david-tabibi2008verified |
arxiv-4532 | 0808.1128 | Dynamic Connectivity: Connecting to Networks and Geometry | <|reference_start|>Dynamic Connectivity: Connecting to Networks and Geometry: Dynamic connectivity is a well-studied problem, but so far the most compelling progress has been confined to the edge-update model: maintain an understanding of connectivity in an undirected graph, subject to edge insertions and deletions. In this paper, we study two more challenging, yet equally fundamental problems. Subgraph connectivity asks to maintain an understanding of connectivity under vertex updates: updates can turn vertices on and off, and queries refer to the subgraph induced by "on" vertices. (For instance, this is closer to applications in networks of routers, where node faults may occur.) We describe a data structure supporting vertex updates in O (m^{2/3}) amortized time, where m denotes the number of edges in the graph. This greatly improves over the previous result [Chan, STOC'02], which required fast matrix multiplication and had an update time of O(m^0.94). The new data structure is also simpler. Geometric connectivity asks to maintain a dynamic set of n geometric objects, and query connectivity in their intersection graph. (For instance, the intersection graph of balls describes connectivity in a network of sensors with bounded transmission radius.) Previously, nontrivial fully dynamic results were known only for special cases like axis-parallel line segments and rectangles. We provide similarly improved update times, O (n^{2/3}), for these special cases. Moreover, we show how to obtain sublinear update bounds for virtually all families of geometric objects which allow sublinear-time range queries, such as arbitrary 2D line segments, d-dimensional simplices, and d-dimensional balls.<|reference_end|> | arxiv | @article{chan2008dynamic,
title={Dynamic Connectivity: Connecting to Networks and Geometry},
author={Timothy M. Chan and Mihai Patrascu and Liam Roditty},
journal={arXiv preprint arXiv:0808.1128},
year={2008},
archivePrefix={arXiv},
eprint={0808.1128},
primaryClass={cs.DS cs.CG}
} | chan2008dynamic |
arxiv-4533 | 0808.1207 | Optimally Efficient Prefix Search and Multicast in Structured P2P Networks | <|reference_start|>Optimally Efficient Prefix Search and Multicast in Structured P2P Networks: Searching in P2P networks is fundamental to all overlay networks. P2P networks based on Distributed Hash Tables (DHT) are optimized for single key lookups, whereas unstructured networks offer more complex queries at the cost of increased traffic and uncertain success rates. Our Distributed Tree Construction (DTC) approach enables structured P2P networks to perform prefix search, range queries, and multicast in an optimal way. It achieves this by creating a spanning tree over the peers in the search area, using only information available locally on each peer. Because DTC creates a spanning tree, it can query all the peers in the search area with a minimal number of messages. Furthermore, we show that the tree depth has the same upper bound as a regular DHT lookup which in turn guarantees fast and responsive runtime behavior. By placing objects with a region quadtree, we can perform a prefix search or a range query in a freely selectable area of the DHT. Our DTC algorithm is DHT-agnostic and works with most existing DHTs. We evaluate the performance of DTC over several DHTs by comparing the performance to existing application-level multicast solutions, we show that DTC sends 30-250% fewer messages than common solutions.<|reference_end|> | arxiv | @article{bradler2008optimally,
title={Optimally Efficient Prefix Search and Multicast in Structured P2P
Networks},
author={Dirk Bradler and Jussi Kangasharju and Max Muehlhaeuser},
journal={arXiv preprint arXiv:0808.1207},
year={2008},
archivePrefix={arXiv},
eprint={0808.1207},
primaryClass={cs.NI}
} | bradler2008optimally |
arxiv-4534 | 0808.1211 | Commonsense Knowledge, Ontology and Ordinary Language | <|reference_start|>Commonsense Knowledge, Ontology and Ordinary Language: Over two decades ago a "quite revolution" overwhelmingly replaced knowledgebased approaches in natural language processing (NLP) by quantitative (e.g., statistical, corpus-based, machine learning) methods. Although it is our firm belief that purely quantitative approaches cannot be the only paradigm for NLP, dissatisfaction with purely engineering approaches to the construction of large knowledge bases for NLP are somewhat justified. In this paper we hope to demonstrate that both trends are partly misguided and that the time has come to enrich logical semantics with an ontological structure that reflects our commonsense view of the world and the way we talk about in ordinary language. In this paper it will be demonstrated that assuming such an ontological structure a number of challenges in the semantics of natural language (e.g., metonymy, intensionality, copredication, nominal compounds, etc.) can be properly and uniformly addressed.<|reference_end|> | arxiv | @article{saba2008commonsense,
title={Commonsense Knowledge, Ontology and Ordinary Language},
author={Walid S. Saba},
journal={arXiv preprint arXiv:0808.1211},
year={2008},
archivePrefix={arXiv},
eprint={0808.1211},
primaryClass={cs.AI cs.CL}
} | saba2008commonsense |
arxiv-4535 | 0808.1215 | A Formal Foundation for XrML | <|reference_start|>A Formal Foundation for XrML: XrML is becoming a popular language in industry for writing software licenses. The semantics for XrML is implicitly given by an algorithm that determines if a permission follows from a set of licenses. We focus on a fragment of the language and use it to highlight some problematic aspects of the algorithm. We then correct the problems, introduce formal semantics, and show that our semantics captures the (corrected) algorithm. Next, we consider the complexity of determining if a permission is implied by a set of XrML licenses. We prove that the general problem is undecidable, but it is polynomial-time computable for an expressive fragment of the language. We extend XrML to capture a wider range of licenses by adding negation to the language. Finally, we discuss the key differences between XrML and MPEG-21, an international standard based on XrML.<|reference_end|> | arxiv | @article{halpern2008a,
title={A Formal Foundation for XrML},
author={Joseph Y. Halpern and Vicky Weissman},
journal={arXiv preprint arXiv:0808.1215},
year={2008},
archivePrefix={arXiv},
eprint={0808.1215},
primaryClass={cs.CR cs.LO}
} | halpern2008a |
arxiv-4536 | 0808.1246 | Minimum Dissatisfaction Personnel Scheduling | <|reference_start|>Minimum Dissatisfaction Personnel Scheduling: In this paper we consider two problems regarding the scheduling of available personnel in order to perform a given quantity of work, which can be arbitrarily decomposed into a sequence of activities. We are interested in schedules which minimize the overall dissatisfaction, where each employee's dissatisfaction is modeled as a time-dependent linear function. For the two situations considered we provide a detailed mathematical analysis, as well as efficient algorithms for determining optimal schedules.<|reference_end|> | arxiv | @article{andreica2008minimum,
title={Minimum Dissatisfaction Personnel Scheduling},
author={Mugurel Ionut Andreica, Romulus Andreica, Angela Andreica},
journal={ARA Congress, Boston : United States (2008)},
year={2008},
archivePrefix={arXiv},
eprint={0808.1246},
primaryClass={cs.DS}
} | andreica2008minimum |
arxiv-4537 | 0808.1247 | Self-Motions of General 3-RPR Planar Parallel Robots | <|reference_start|>Self-Motions of General 3-RPR Planar Parallel Robots: This paper studies the kinematic geometry of general 3-RPR planar parallel robots with actuated base joints. These robots, while largely overlooked, have simple direct kinematics and large singularity-free workspace. Furthermore, their kinematic geometry is the same as that of a newly developed parallel robot with SCARA-type motions. Starting from the direct and inverse kinematic model, the expressions for the singularity loci of 3-RPR planar parallel robots are determined. Then, the global behaviour at all singularities is geometrically described by studying the degeneracy of the direct kinematic model. Special cases of self-motions are then examined and the degree of freedom gained in such special configurations is kinematically interpreted. Finally, a practical example is discussed and experimental validations performed on an actual robot prototype are presented.<|reference_end|> | arxiv | @article{briot2008self-motions,
title={Self-Motions of General 3-RPR Planar Parallel Robots},
author={S'ebastien Briot (DGMA), Ilian Bonev (GPA), Damien Chablat (IRCCyN),
Philippe Wenger (IRCCyN), Vigen Arakelian (DGMA)},
journal={International Journal of Robotics Research 27, 7 (2008) pp.
855-866},
year={2008},
doi={10.1177/0278364908092466},
archivePrefix={arXiv},
eprint={0808.1247},
primaryClass={cs.RO}
} | briot2008self-motions |
arxiv-4538 | 0808.1343 | Policy and Legal Challenges of Virtual Worlds and Social Network Sites | <|reference_start|>Policy and Legal Challenges of Virtual Worlds and Social Network Sites: This paper addresses policy challenges of complex virtual environments such as virtual worlds, social network sites, and massive multiplayer online games. The complexity of these environments--apparent by the rich user interactions and sophisticated user-generated content that they offer--poses unique challenges for policy management and compliance. These challenges are also impacting the life cycle of the software system that implements the virtual environment. The goal of this paper is to identify and sketch important legal and policy challenges of virtual environments and how they affect stakeholders (i.e., operators, users, and lawmakers). Given the increasing significance of virtual environments, we expect that tackling these challenges will become increasingly important in the future.<|reference_end|> | arxiv | @article{kienle2008policy,
title={Policy and Legal Challenges of Virtual Worlds and Social Network Sites},
author={Holger M. Kienle, Andreas Lober, Hausi A. M"uller},
journal={arXiv preprint arXiv:0808.1343},
year={2008},
archivePrefix={arXiv},
eprint={0808.1343},
primaryClass={cs.CY}
} | kienle2008policy |
arxiv-4539 | 0808.1354 | Ockham's razor and reasoning about information flow | <|reference_start|>Ockham's razor and reasoning about information flow: What is the minimal algebraic structure to reason about information flow? Do we really need the full power of Boolean algebras with co-closure and de Morgan dual operators? How much can we weaken and still be able to reason about multi-agent scenarios in a tidy compositional way? This paper provides some answers.<|reference_end|> | arxiv | @article{sadrzadeh2008ockham's,
title={Ockham's razor and reasoning about information flow},
author={Mehrnoosh Sadrzadeh},
journal={arXiv preprint arXiv:0808.1354},
year={2008},
archivePrefix={arXiv},
eprint={0808.1354},
primaryClass={math.LO cs.LO}
} | sadrzadeh2008ockham's |
arxiv-4540 | 0808.1364 | On Bounded Integer Programming | <|reference_start|>On Bounded Integer Programming: We present an efficient reduction from the Bounded integer programming (BIP) to the Subspace avoiding problem (SAP) in lattice theory. The reduction has some special properties with some interesting consequences. The first is the new upper time bound for BIP, $poly(\varphi)\cdot n^{n+o(n)}$ (where $n$ and $\varphi$ are the dimension and the input size of the problem, respectively). This is the best bound up to now for BIP. The second consequence is the proof that #SAP, for some norms, is #P-hard under semi-reductions. It follows that the counting version of the Generalized closest vector problem is also #P-hard under semi-reductions. Furthermore, we also show that under some reasonable assumptions, BIP is solvable in probabilistic time $2^{O(n)}$.<|reference_end|> | arxiv | @article{khoát2008on,
title={On Bounded Integer Programming},
author={Th^an Quang Kho'at},
journal={arXiv preprint arXiv:0808.1364},
year={2008},
archivePrefix={arXiv},
eprint={0808.1364},
primaryClass={cs.CC cs.DM}
} | khoát2008on |
arxiv-4541 | 0808.1368 | On some deterministic dictionaries supporting sparsity | <|reference_start|>On some deterministic dictionaries supporting sparsity: We describe a new construction of an incoherent dictionary, referred to as the oscillator dictionary, which is based on considerations in the representation theory of finite groups. The oscillator dictionary consists of order of p^5 unit vectors in a Hilbert space of dimension p, where p is an odd prime, whose pairwise inner products have magnitude of at most 4/sqrt(p). An explicit algorithm to construct a large portion of the oscillator dictionary is presented.<|reference_end|> | arxiv | @article{gurevich2008on,
title={On some deterministic dictionaries supporting sparsity},
author={Shamgar Gurevich (UC Berkeley), Ronny Hadani (University of Chicago),
Nir Sochen (Tel Aviv University)},
journal={Special issue on sparsity, the Journal of Fourier Analysis and
Applications, Vol. 14, 859-876, Dec. 2008},
year={2008},
archivePrefix={arXiv},
eprint={0808.1368},
primaryClass={cs.IT math.IT}
} | gurevich2008on |
arxiv-4542 | 0808.1378 | A Novel Symbolic Type Neural Network Model- Application to River Flow Forecasting | <|reference_start|>A Novel Symbolic Type Neural Network Model- Application to River Flow Forecasting: In this paper we introduce a new symbolic type neural tree network called symbolic function network (SFN) that is based on using elementary functions to model systems in a symbolic form. The proposed formulation permits feature selection, functional selection, and flexible structure. We applied this model on the River Flow forecasting problem. The results found to be superior in both fitness and sparsity.<|reference_end|> | arxiv | @article{eskander2008a,
title={A Novel Symbolic Type Neural Network Model- Application to River Flow
Forecasting},
author={George S. Eskander, and Amir F. Atiya},
journal={arXiv preprint arXiv:0808.1378},
year={2008},
archivePrefix={arXiv},
eprint={0808.1378},
primaryClass={cs.NE cs.SC}
} | eskander2008a |
arxiv-4543 | 0808.1400 | A Class of Maximal-Rate, Low-PAPR, Non-square Complex Orthogonal Designs | <|reference_start|>A Class of Maximal-Rate, Low-PAPR, Non-square Complex Orthogonal Designs: Space-time block codes (STBCs) from non-square complex orthogonal designs are bandwidth efficient when compared with those from square real/complex orthogonal designs. Though there exists rate-1 ROD for any number of transmit antennas, rate-1 complex orthogonal designs (COD) does not exist for more than 2 transmit antennas. Liang (IEEE Trans. Inform. Theory, 2003) and Lu et al (IEEE Trans. Inform. Theory, 2005) have constructed a class of maximal rate non-square CODs where the rate is ${1/2}+\frac{1}{n}$ if number of transmit antennas $n$ is even and ${1/2}+\frac{1}{n+1}$ if $n$ is odd. In this paper, we present a simple construction for maximal rate non-square CODs obtained from square CODs which resembles the construction of rate-1 non-square RODs from square RODs. These designs are shown to be amenable for construction of a class of generalized CODs (called Coordinate-Interleaved Scaled CODs) with low peak-to-average power ratio (PAPR) having the same parameters as the maximal rate codes. Simulation results indicate that these codes perform better than the existing maximal rate codes under peak power constraint while performing the same under average power constraint.<|reference_end|> | arxiv | @article{das2008a,
title={A Class of Maximal-Rate, Low-PAPR, Non-square Complex Orthogonal Designs},
author={Smarajit Das, B. Sundar Rajan},
journal={arXiv preprint arXiv:0808.1400},
year={2008},
archivePrefix={arXiv},
eprint={0808.1400},
primaryClass={cs.IT math.IT}
} | das2008a |
arxiv-4544 | 0808.1410 | Image Steganography, a New Approach for Transferring Security Information | <|reference_start|>Image Steganography, a New Approach for Transferring Security Information: Steganography is the art of hiding the fact that communication is taking place, by hiding information in other information. Many different carrier file formats can be used, but digital images are the most popular because of their frequency on the Internet. For hiding secret information in images, there exists a large variety of steganographic techniques some are more complex than others and all of them have respective strong and weak points. Different applications have different requirements of the steganography technique used. For example, some applications may require absolute invisibility of the secret information, while others require a larger secret message to be hidden. This paper intends to give an overview of image steganography, its uses and techniques. It also attempts to identify the requirements of a good steganographic algorithm and briefly reflects on which steganographic techniques are more suitable for which applications.<|reference_end|> | arxiv | @article{bahar2008image,
title={Image Steganography, a New Approach for Transferring Security
Information},
author={H. B. Bahar, Ali Aboutalebi},
journal={arXiv preprint arXiv:0808.1410},
year={2008},
archivePrefix={arXiv},
eprint={0808.1410},
primaryClass={cs.CR}
} | bahar2008image |
arxiv-4545 | 0808.1417 | The finite harmonic oscillator and its associated sequences | <|reference_start|>The finite harmonic oscillator and its associated sequences: A system of functions (signals) on the finite line, called the oscillator system, is described and studied. Applications of this system for discrete radar and digital communication theory are explained. Keywords: Weil representation, commutative subgroups, eigenfunctions, random behavior, deterministic construction<|reference_end|> | arxiv | @article{gurevich2008the,
title={The finite harmonic oscillator and its associated sequences},
author={Shamgar Gurevich, Ronny Hadani, Nir Sochen},
journal={PNAS, July 22, 2008 vol. 105 no. 29 9869-9873
http://www.pnas.org/content/105/29/9869.abstract},
year={2008},
doi={10.1073/pnas.0801656105},
archivePrefix={arXiv},
eprint={0808.1417},
primaryClass={cs.IT cs.CR cs.DM math-ph math.GR math.IT math.MP math.NT math.PR math.QA math.RT math.SG quant-ph}
} | gurevich2008the |
arxiv-4546 | 0808.1431 | A General Theory of Computational Scalability Based on Rational Functions | <|reference_start|>A General Theory of Computational Scalability Based on Rational Functions: The universal scalability law of computational capacity is a rational function C_p = P(p)/Q(p) with P(p) a linear polynomial and Q(p) a second-degree polynomial in the number of physical processors p, that has been long used for statistical modeling and prediction of computer system performance. We prove that C_p is equivalent to the synchronous throughput bound for a machine-repairman with state-dependent service rate. Simpler rational functions, such as Amdahl's law and Gustafson speedup, are corollaries of this queue-theoretic bound. C_p is further shown to be both necessary and sufficient for modeling all practical characteristics of computational scalability.<|reference_end|> | arxiv | @article{gunther2008a,
title={A General Theory of Computational Scalability Based on Rational
Functions},
author={Neil J. Gunther},
journal={arXiv preprint arXiv:0808.1431},
year={2008},
archivePrefix={arXiv},
eprint={0808.1431},
primaryClass={cs.PF cs.DC}
} | gunther2008a |
arxiv-4547 | 0808.1455 | Personal Semantic Web Through A Space Based Computing Environment | <|reference_start|>Personal Semantic Web Through A Space Based Computing Environment: The Semantic Web through technologies such to support the canonical representation information and presenting it to users in a method by which its meaning can be understood or at least communi- cated and interpreted by all parties. As the Semantic Web evolves into more of a computing platform rather than an information platform more dynamic structures, interactions and behaviours will evolve leading to systems which localise and personalise this Dynamic Semantic Web.<|reference_end|> | arxiv | @article{oliver2008personal,
title={Personal Semantic Web Through A Space Based Computing Environment},
author={Ian Oliver and Jukka Honkola},
journal={arXiv preprint arXiv:0808.1455},
year={2008},
archivePrefix={arXiv},
eprint={0808.1455},
primaryClass={cs.NI cs.MA}
} | oliver2008personal |
arxiv-4548 | 0808.1470 | Encompression Using Two-dimensional Cellular Automata Rules | <|reference_start|>Encompression Using Two-dimensional Cellular Automata Rules: In this paper, we analyze the algebraic structure of some null boundary as well as some periodic boundary 2-D Cellular Automata (CA) rules by introducing a new matrix multiplication operation using only AND, OR instead of most commonly used AND, EX-OR. This class includes any CA whose rule, when written as an algebra, is a finite Abelean cyclic group in case of periodic boundary and a finite commutative cyclic monoid in case of null boundary CA respectively. The concept of 1-D Multiple Attractor Cellular Automata (MACA) is extended to 2-D. Using the family of 2-D MACA and the finite Abelian cyclic group, an efficient encompression algorithm is proposed for binary images.<|reference_end|> | arxiv | @article{sahoo2008encompression,
title={Encompression Using Two-dimensional Cellular Automata Rules},
author={Sudhakar Sahoo, Sanjaya Sahoo, Birendra Kumar Nayak and Pabitra Pal
Choudhury},
journal={arXiv preprint arXiv:0808.1470},
year={2008},
archivePrefix={arXiv},
eprint={0808.1470},
primaryClass={cs.DM cs.CR}
} | sahoo2008encompression |
arxiv-4549 | 0808.1495 | The finite harmonic oscillator and its applications to sequences, communication and radar | <|reference_start|>The finite harmonic oscillator and its applications to sequences, communication and radar: A novel system, called the oscillator system, consisting of order of p^3 functions (signals) on the finite field F_p; with p an odd prime, is described and studied. The new functions are proved to satisfy good auto-correlation, cross-correlation and low peak-to-average power ratio properties. Moreover, the oscillator system is closed under the operation of discrete Fourier transform. Applications of the oscillator system for discrete radar and digital communication theory are explained. Finally, an explicit algorithm to construct the oscillator system is presented.<|reference_end|> | arxiv | @article{gurevich2008the,
title={The finite harmonic oscillator and its applications to sequences,
communication and radar},
author={Shamgar Gurevich, Ronny Hadani, Nir Sochen},
journal={IEEE Transactions on Information Theory, vol. 54, no. 9, September
2008},
year={2008},
doi={10.1109/TIT.2008.926440},
archivePrefix={arXiv},
eprint={0808.1495},
primaryClass={cs.IT math.IT}
} | gurevich2008the |
arxiv-4550 | 0808.1505 | An Almost-Surely Terminating Polynomial Protocol for Asynchronous Byzantine Agreement with Optimal Resilience | <|reference_start|>An Almost-Surely Terminating Polynomial Protocol for Asynchronous Byzantine Agreement with Optimal Resilience: Consider an asynchronous system with private channels and $n$ processes, up to $t$ of which may be faulty. We settle a longstanding open question by providing a Byzantine agreement protocol that simultaneously achieves three properties: 1. (optimal) resilience: it works as long as $n>3t$ 2. (almost-sure) termination: with probability one, all nonfaulty processes terminate 3. (polynomial) efficiency: the expected computation time, memory consumption, message size, and number of messages sent are all polynomial in $n$. Earlier protocols have achieved only two of these three properties. In particular, the protocol of Bracha is not polynomially efficient, the protocol of Feldman and Micali is not optimally resilient, and the protocol of Canetti and Rabin does not have almost-sure termination. Our protocol utilizes a new primitive called shunning (asynchronous) verifiable secret sharing (SVSS), which ensures, roughly speaking, that either a secret is successfully shared or a new faulty process is ignored from this point onwards by some nonfaulty process.<|reference_end|> | arxiv | @article{abraham2008an,
title={An Almost-Surely Terminating Polynomial Protocol for Asynchronous
Byzantine Agreement with Optimal Resilience},
author={Ittai Abraham, Danny Dolev, and Joseph Y. Halpern},
journal={arXiv preprint arXiv:0808.1505},
year={2008},
archivePrefix={arXiv},
eprint={0808.1505},
primaryClass={cs.DC}
} | abraham2008an |
arxiv-4551 | 0808.1508 | Comparison between CPBPV, ESC/Java, CBMC, Blast, EUREKA and Why for Bounded Program Verification | <|reference_start|>Comparison between CPBPV, ESC/Java, CBMC, Blast, EUREKA and Why for Bounded Program Verification: This report describes experimental results for a set of benchmarks on program verification. It compares the capabilities of CPBVP "Constraint Programming framework for Bounded Program Verification" [4] with the following frameworks: ESC/Java, CBMC, Blast, EUREKA and Why.<|reference_end|> | arxiv | @article{collavizza2008comparison,
title={Comparison between CPBPV, ESC/Java, CBMC, Blast, EUREKA and Why for
Bounded Program Verification},
author={H'el`ene Collavizza (I3S), Michel Rueher (I3S), Pascal Van
Hentenryck (Brown University)},
journal={arXiv preprint arXiv:0808.1508},
year={2008},
archivePrefix={arXiv},
eprint={0808.1508},
primaryClass={cs.SE cs.AI cs.LO}
} | collavizza2008comparison |
arxiv-4552 | 0808.1549 | The Peculiar Phase Structure of Random Graph Bisection | <|reference_start|>The Peculiar Phase Structure of Random Graph Bisection: The mincut graph bisection problem involves partitioning the n vertices of a graph into disjoint subsets, each containing exactly n/2 vertices, while minimizing the number of "cut" edges with an endpoint in each subset. When considered over sparse random graphs, the phase structure of the graph bisection problem displays certain familiar properties, but also some surprises. It is known that when the mean degree is below the critical value of 2 log 2, the cutsize is zero with high probability. We study how the minimum cutsize increases with mean degree above this critical threshold, finding a new analytical upper bound that improves considerably upon previous bounds. Combined with recent results on expander graphs, our bound suggests the unusual scenario that random graph bisection is replica symmetric up to and beyond the critical threshold, with a replica symmetry breaking transition possibly taking place above the threshold. An intriguing algorithmic consequence is that although the problem is NP-hard, we can find near-optimal cutsizes (whose ratio to the optimal value approaches 1 asymptotically) in polynomial time for typical instances near the phase transition.<|reference_end|> | arxiv | @article{percus2008the,
title={The Peculiar Phase Structure of Random Graph Bisection},
author={Allon G. Percus, Gabriel Istrate, Bruno Goncalves, Robert Z. Sumi and
Stefan Boettcher},
journal={J. Math. Phys. 49, 125219 (2008)},
year={2008},
doi={10.1063/1.3043666},
number={LA-UR 08-5099},
archivePrefix={arXiv},
eprint={0808.1549},
primaryClass={cond-mat.stat-mech cond-mat.dis-nn cs.CC cs.DM}
} | percus2008the |
arxiv-4553 | 0808.1599 | Finding cores of random 2-SAT formulae via Poisson cloning | <|reference_start|>Finding cores of random 2-SAT formulae via Poisson cloning: For the random 2-SAT formula $F(n,p)$, let $F_C (n,p)$ be the formula left after the pure literal algorithm applied to $F(n,p)$ stops. Using the recently developed Poisson cloning model together with the cut-off line algorithm (COLA), we completely analyze the structure of $F_{C} (n,p)$. In particular, it is shown that, for $\gl:= p(2n-1) = 1+\gs $ with $\gs\gg n^{-1/3}$, the core of $F(n,p)$ has $\thl^2 n +O((\thl n)^{1/2})$ variables and $\thl^2 \gl n+O((\thl n))^{1/2}$ clauses, with high probability, where $\thl$ is the larger solution of the equation $\th- (1-e^{-\thl \gl})=0$. We also estimate the probability of $F(n,p)$ being satisfiable to obtain $$ \pr[ F_2(n, \sfrac{\gl}{2n-1}) is satisfiable ] = \caseth{1-\frac{1+o(1)}{16\gs^3 n}}{if $\gl= 1-\gs$ with $\gs\gg n^{-1/3}$}{}{}{e^{-\Theta(\gs^3n)}}{if $\gl=1+\gs$ with $\gs\gg n^{-1/3}$,} $$ where $o(1)$ goes to 0 as $\gs$ goes to 0. This improves the bounds of Bollob\'as et al. \cite{BBCKW}.<|reference_end|> | arxiv | @article{kim2008finding,
title={Finding cores of random 2-SAT formulae via Poisson cloning},
author={Jeong Han Kim},
journal={arXiv preprint arXiv:0808.1599},
year={2008},
archivePrefix={arXiv},
eprint={0808.1599},
primaryClass={math.CO cs.CC math.PR}
} | kim2008finding |
arxiv-4554 | 0808.1641 | Characterization Of any Non-linear Boolean function Using A Set of Linear Operators | <|reference_start|>Characterization Of any Non-linear Boolean function Using A Set of Linear Operators: Global dynamics of a non-linear Cellular Automata is, in general irregular, asymmetric and unpredictable as opposed to that of a linear CA, which is highly systematic and tractable. In the past efforts have been made to systematize non-linear CA evolutions in the light of Boolean derivatives and Jacobian Matrices. In this paper two different efforts have been made: first we try to systematize non-linear CA evolution in the light of deviant states and non-deviant states. For all the non-deviant states the nearest linear rule matrix is applicable where as for the deviant states we have a set of other matrices. Second using algebraic manipulation, an efficient algorithm is proposed by which every Non-linear Boolean function can be characterized by a sequence of binary matrices.<|reference_end|> | arxiv | @article{sahoo2008characterization,
title={Characterization Of any Non-linear Boolean function Using A Set of
Linear Operators},
author={Sudhakar Sahoo, Pabitra Pal Choudhury, Mithun Chakraborty},
journal={arXiv preprint arXiv:0808.1641},
year={2008},
archivePrefix={arXiv},
eprint={0808.1641},
primaryClass={cs.CC nlin.CG}
} | sahoo2008characterization |
arxiv-4555 | 0808.1657 | Periodicity, repetitions, and orbits of an automatic sequence | <|reference_start|>Periodicity, repetitions, and orbits of an automatic sequence: We revisit a technique of S. Lehr on automata and use it to prove old and new results in a simple way. We give a very simple proof of the 1986 theorem of Honkala that it is decidable whether a given k-automatic sequence is ultimately periodic. We prove that it is decidable whether a given k-automatic sequence is overlap-free (or squareefree, or cubefree, etc.) We prove that the lexicographically least sequence in the orbit closure of a k-automatic sequence is k-automatic, and use this last result to show that several related quantities, such as the critical exponent, irrationality measure, and recurrence quotient for Sturmian words with slope alpha, have automatic continued fraction expansions if alpha does.<|reference_end|> | arxiv | @article{allouche2008periodicity,,
title={Periodicity, repetitions, and orbits of an automatic sequence},
author={Jean-Paul Allouche, Narad Rampersad, Jeffrey Shallit},
journal={arXiv preprint arXiv:0808.1657},
year={2008},
archivePrefix={arXiv},
eprint={0808.1657},
primaryClass={cs.DM cs.FL}
} | allouche2008periodicity, |
arxiv-4556 | 0808.1661 | Medical robotics: where we come from, where we are and where we could go | <|reference_start|>Medical robotics: where we come from, where we are and where we could go: This short note presents a viewpoint about medical robotics.<|reference_end|> | arxiv | @article{troccaz2008medical,
title={Medical robotics: where we come from, where we are and where we could go},
author={Jocelyne Troccaz (TIMC)},
journal={The Industrial Robot 35, 4 (2008) 289},
year={2008},
archivePrefix={arXiv},
eprint={0808.1661},
primaryClass={cs.RO}
} | troccaz2008medical |
arxiv-4557 | 0808.1671 | Algorithmic Pricing via Virtual Valuations | <|reference_start|>Algorithmic Pricing via Virtual Valuations: Algorithmic pricing is the computational problem that sellers (e.g., in supermarkets) face when trying to set prices for their items to maximize their profit in the presence of a known demand. Guruswami et al. (2005) propose this problem and give logarithmic approximations (in the number of consumers) when each consumer's values for bundles are known precisely. Subsequently several versions of the problem have been shown to have poly-logarithmic inapproximability. This problem has direct ties to the important open question of better understanding the Bayesian optimal mechanism in multi-parameter settings; however, logarithmic approximations are inadequate for this purpose. It is therefore of vital interest to consider special cases where constant approximations are possible. We consider the unit-demand variant of this problem. Here a consumer has a valuation for each different item and their value for a set of items is simply the maximum value they have for any item in the set. We assume that the preferences of the consumers are drawn from a distribution, the standard assumption in economics; furthermore, the setting of a specific set of customers with known preferences, which is employed in all prior work in algorithmic pricing, is a special case of this general problem, where there is a discrete Bayesian distribution for preferences specified by picking one consumer uniformly from the given set of consumers. Our work complements these existing works by considering the case where the consumer's valuations for the different items are independent random variables. Our main result is a constant approximation that makes use of an interesting connection between this problem and the concept of virtual valuations from the single-parameter Bayesian optimal mechanism design literature.<|reference_end|> | arxiv | @article{chawla2008algorithmic,
title={Algorithmic Pricing via Virtual Valuations},
author={Shuchi Chawla and Jason Hartline and Robert Kleinberg},
journal={arXiv preprint arXiv:0808.1671},
year={2008},
archivePrefix={arXiv},
eprint={0808.1671},
primaryClass={cs.GT cs.DS}
} | chawla2008algorithmic |
arxiv-4558 | 0808.1721 | Initial Results on the F-logic to OWL Bi-directional Translation on a Tabled Prolog Engine | <|reference_start|>Initial Results on the F-logic to OWL Bi-directional Translation on a Tabled Prolog Engine: In this paper, we show our results on the bi-directional data exchange between the F-logic language supported by the Flora2 system and the OWL language. Most of the TBox and ABox axioms are translated preserving the semantics between the two representations, such as: proper inclusion, individual definition, functional properties, while some axioms and restrictions require a change in the semantics, such as: numbered and qualified cardinality restrictions. For the second case, we translate the OWL definite style inference rules into F-logic style constraints. We also describe a set of reasoning examples using the above translation, including the reasoning in Flora2 of a variety of ABox queries.<|reference_end|> | arxiv | @article{fodor2008initial,
title={Initial Results on the F-logic to OWL Bi-directional Translation on a
Tabled Prolog Engine},
author={Paul Fodor},
journal={arXiv preprint arXiv:0808.1721},
year={2008},
archivePrefix={arXiv},
eprint={0808.1721},
primaryClass={cs.AI cs.SE}
} | fodor2008initial |
arxiv-4559 | 0808.1744 | Our Brothers' Keepers: Secure Routing with High Performance | <|reference_start|>Our Brothers' Keepers: Secure Routing with High Performance: The Trinity (Brodsky et al., 2007) spam classification system is based on a distributed hash table that is implemented using a structured peer-to-peer overlay. Such an overlay must be capable of processing hundreds of messages per second, and must be able to route messages to their destination even in the presence of failures and malicious peers that misroute packets or inject fraudulent routing information into the system. Typically there is tension between the requirements to route messages securely and efficiently in the overlay. We describe a secure and efficient routing extension that we developed within the I3 (Stoica et al. 2004) implementation of the Chord (Stoica et al. 2001) overlay. Secure routing is accomplished through several complementary approaches: First, peers in close proximity form overlapping groups that police themselves to identify and mitigate fraudulent routing information. Second, a form of random routing solves the problem of entire packet flows passing through a malicious peer. Third, a message authentication mechanism links each message to it sender, preventing spoofing. Fourth, each peer's identifier links the peer to its network address, and at the same time uniformly distributes the peers in the key-space. Lastly, we present our initial evaluation of the system, comprising a 255 peer overlay running on a local cluster. We describe our methodology and show that the overhead of our secure implementation is quite reasonable.<|reference_end|> | arxiv | @article{brodsky2008our,
title={Our Brothers' Keepers: Secure Routing with High Performance},
author={Alex Brodsky and Scott Lindenberg},
journal={arXiv preprint arXiv:0808.1744},
year={2008},
archivePrefix={arXiv},
eprint={0808.1744},
primaryClass={cs.DC cs.CR cs.NI}
} | brodsky2008our |
arxiv-4560 | 0808.1753 | Index wiki database: design and experiments | <|reference_start|>Index wiki database: design and experiments: With the fantastic growth of Internet usage, information search in documents of a special type called a "wiki page" that is written using a simple markup language, has become an important problem. This paper describes the software architectural model for indexing wiki texts in three languages (Russian, English, and German) and the interaction between the software components (GATE, Lemmatizer, and Synarcher). The inverted file index database was designed using visual tool DBDesigner. The rules for parsing Wikipedia texts are illustrated by examples. Two index databases of Russian Wikipedia (RW) and Simple English Wikipedia (SEW) are built and compared. The size of RW is by order of magnitude higher than SEW (number of words, lexemes), though the growth rate of number of pages in SEW was found to be 14% higher than in Russian, and the rate of acquisition of new words in SEW lexicon was 7% higher during a period of five months (from September 2007 to February 2008). The Zipf's law was tested with both Russian and Simple Wikipedias. The entire source code of the indexing software and the generated index databases are freely available under GPL (GNU General Public License).<|reference_end|> | arxiv | @article{krizhanovsky2008index,
title={Index wiki database: design and experiments},
author={A. A. Krizhanovsky},
journal={arXiv preprint arXiv:0808.1753},
year={2008},
archivePrefix={arXiv},
eprint={0808.1753},
primaryClass={cs.IR cs.CL}
} | krizhanovsky2008index |
arxiv-4561 | 0808.1762 | Communication Complexities of XOR functions | <|reference_start|>Communication Complexities of XOR functions: We call $F:\{0, 1\}^n\times \{0, 1\}^n\to\{0, 1\}$ a symmetric XOR function if for a function $S:\{0, 1, ..., n\}\to\{0, 1\}$, $F(x, y)=S(|x\oplus y|)$, for any $x, y\in\{0, 1\}^n$, where $|x\oplus y|$ is the Hamming weight of the bit-wise XOR of $x$ and $y$. We show that for any such function, (a) the deterministic communication complexity is always $\Theta(n)$ except for four simple functions that have a constant complexity, and (b) up to a polylog factor, the error-bounded randomized and quantum communication complexities are $\Theta(r_0+r_1)$, where $r_0$ and $r_1$ are the minimum integers such that $r_0, r_1\leq n/2$ and $S(k)=S(k+2)$ for all $k\in[r_0, n-r_1)$.<|reference_end|> | arxiv | @article{shi2008communication,
title={Communication Complexities of XOR functions},
author={Yaoyun Shi, Zhiqiang Zhang},
journal={arXiv preprint arXiv:0808.1762},
year={2008},
archivePrefix={arXiv},
eprint={0808.1762},
primaryClass={quant-ph cs.CC}
} | shi2008communication |
arxiv-4562 | 0808.1766 | The Optimal Quantile Estimator for Compressed Counting | <|reference_start|>The Optimal Quantile Estimator for Compressed Counting: Compressed Counting (CC) was recently proposed for very efficiently computing the (approximate) $\alpha$th frequency moments of data streams, where $0<\alpha <= 2$. Several estimators were reported including the geometric mean estimator, the harmonic mean estimator, the optimal power estimator, etc. The geometric mean estimator is particularly interesting for theoretical purposes. For example, when $\alpha -> 1$, the complexity of CC (using the geometric mean estimator) is $O(1/\epsilon)$, breaking the well-known large-deviation bound $O(1/\epsilon^2)$. The case $\alpha\approx 1$ has important applications, for example, computing entropy of data streams. For practical purposes, this study proposes the optimal quantile estimator. Compared with previous estimators, this estimator is computationally more efficient and is also more accurate when $\alpha> 1$.<|reference_end|> | arxiv | @article{li2008the,
title={The Optimal Quantile Estimator for Compressed Counting},
author={Ping Li},
journal={arXiv preprint arXiv:0808.1766},
year={2008},
archivePrefix={arXiv},
eprint={0808.1766},
primaryClass={cs.DS}
} | li2008the |
arxiv-4563 | 0808.1771 | A Very Efficient Scheme for Estimating Entropy of Data Streams Using Compressed Counting | <|reference_start|>A Very Efficient Scheme for Estimating Entropy of Data Streams Using Compressed Counting: Compressed Counting (CC)} was recently proposed for approximating the $\alpha$th frequency moments of data streams, for $0<\alpha \leq 2$. Under the relaxed strict-Turnstile model, CC dramatically improves the standard algorithm based on symmetric stable random projections}, especially as $\alpha\to 1$. A direct application of CC is to estimate the entropy, which is an important summary statistic in Web/network measurement and often serves a crucial "feature" for data mining. The R\'enyi entropy and the Tsallis entropy are functions of the $\alpha$th frequency moments; and both approach the Shannon entropy as $\alpha\to 1$. A recent theoretical work suggested using the $\alpha$th frequency moment to approximate the Shannon entropy with $\alpha=1+\delta$ and very small $|\delta|$ (e.g., $<10^{-4}$). In this study, we experiment using CC to estimate frequency moments, R\'enyi entropy, Tsallis entropy, and Shannon entropy, on real Web crawl data. We demonstrate the variance-bias trade-off in estimating Shannon entropy and provide practical recommendations. In particular, our experiments enable us to draw some important conclusions: (1) As $\alpha\to 1$, CC dramatically improves {\em symmetric stable random projections} in estimating frequency moments, R\'enyi entropy, Tsallis entropy, and Shannon entropy. The improvements appear to approach "infinity." (2) Using {\em symmetric stable random projections} and $\alpha = 1+\delta$ with very small $|\delta|$ does not provide a practical algorithm because the required sample size is enormous.<|reference_end|> | arxiv | @article{li2008a,
title={A Very Efficient Scheme for Estimating Entropy of Data Streams Using
Compressed Counting},
author={Ping Li},
journal={arXiv preprint arXiv:0808.1771},
year={2008},
archivePrefix={arXiv},
eprint={0808.1771},
primaryClass={cs.DS}
} | li2008a |
arxiv-4564 | 0808.1787 | Transitive-Closure Spanners | <|reference_start|>Transitive-Closure Spanners: Given a directed graph G = (V,E) and an integer k>=1, a k-transitive-closure-spanner (k-TC-spanner) of G is a directed graph H = (V, E_H) that has (1) the same transitive-closure as G and (2) diameter at most k. These spanners were implicitly studied in access control, data structures, and property testing, and properties of these spanners have been rediscovered over the span of 20 years. The main goal in each of these applications is to obtain the sparsest k-TC-spanners. We bring these diverse areas under the unifying framework of TC-spanners. We initiate the study of approximability of the size of the sparsest k-TC-spanner for a given directed graph. We completely resolve the approximability of 2-TC-spanners, showing that it is Theta(log n) unless P = NP. For k>2, we present a polynomial-time algorithm that finds a k-TC-spanner with size within O((n log n)^{1-1/k}) of the optimum. Our algorithmic techniques also yield algorithms with the best-known approximation ratio for well-studied problems on directed spanners when k>3: DIRECTED k-SPANNER, CLIENT/SERVER DIRECTED k-SPANNER, and k-DIAMETER SPANNING SUBGRAPH. For constant k>=3, we show that the size of the sparsest k-TC-spanner is hard to approximate with 2^{log^{1-eps} n} ratio unless NP \subseteq DTIME(n^{polylog n}}). Finally, we study the size of the sparsest k-TC-spanners for H-minor-free graph families. Combining our constructions with our insight that 2-TC-spanners can be used for designing property testers, we obtain a monotonicity tester with O(log^2 n /eps) queries for any poset whose transitive reduction is an H-minor free digraph, improving the Theta(sqrt(n) log n/eps)-queries required of the tester due to Fischer et al (2002).<|reference_end|> | arxiv | @article{bhattacharyya2008transitive-closure,
title={Transitive-Closure Spanners},
author={Arnab Bhattacharyya, Elena Grigorescu, Kyomin Jung, Sofya
Raskhodnikova, David P. Woodruff},
journal={arXiv preprint arXiv:0808.1787},
year={2008},
archivePrefix={arXiv},
eprint={0808.1787},
primaryClass={cs.DS cs.CC}
} | bhattacharyya2008transitive-closure |
arxiv-4565 | 0808.1802 | Compute and Storage Clouds Using Wide Area High Performance Networks | <|reference_start|>Compute and Storage Clouds Using Wide Area High Performance Networks: We describe a cloud based infrastructure that we have developed that is optimized for wide area, high performance networks and designed to support data mining applications. The infrastructure consists of a storage cloud called Sector and a compute cloud called Sphere. We describe two applications that we have built using the cloud and some experimental studies.<|reference_end|> | arxiv | @article{grossman2008compute,
title={Compute and Storage Clouds Using Wide Area High Performance Networks},
author={Robert L. Grossman, Yunhong Gu, Michael Sabala and Wanzhi Zhang},
journal={arXiv preprint arXiv:0808.1802},
year={2008},
archivePrefix={arXiv},
eprint={0808.1802},
primaryClass={cs.DC}
} | grossman2008compute |
arxiv-4566 | 0808.1928 | Decision Problems For Convex Languages | <|reference_start|>Decision Problems For Convex Languages: In this paper we examine decision problems associated with various classes of convex languages, studied by Ang and Brzozowski (under the name "continuous languages"). We show that we can decide whether a given language L is prefix-, suffix-, factor-, or subword-convex in polynomial time if L is represented by a DFA, but that the problem is PSPACE-hard if L is represented by an NFA. In the case that a regular language is not convex, we prove tight upper bounds on the length of the shortest words demonstrating this fact, in terms of the number of states of an accepting DFA. Similar results are proved for some subclasses of convex languages: the prefix-, suffix-, factor-, and subword-closed languages, and the prefix-, suffix-, factor-, and subword-free languages.<|reference_end|> | arxiv | @article{brzozowski2008decision,
title={Decision Problems For Convex Languages},
author={Janusz Brzozowski, Jeffrey Shallit, and Zhi Xu},
journal={Proc. LATA 2009 Conference, LNICS #5457, pp. 247-258},
year={2008},
doi={10.1007/978-3-642-00982-2_21},
archivePrefix={arXiv},
eprint={0808.1928},
primaryClass={cs.CC cs.DM cs.FL}
} | brzozowski2008decision |
arxiv-4567 | 0808.2017 | Nearly Tight Low Stretch Spanning Trees | <|reference_start|>Nearly Tight Low Stretch Spanning Trees: We prove that any graph $G$ with $n$ points has a distribution $\mathcal{T}$ over spanning trees such that for any edge $(u,v)$ the expected stretch $E_{T \sim \mathcal{T}}[d_T(u,v)/d_G(u,v)]$ is bounded by $\tilde{O}(\log n)$. Our result is obtained via a new approach of building ``highways'' between portals and a new strong diameter probabilistic decomposition theorem.<|reference_end|> | arxiv | @article{abraham2008nearly,
title={Nearly Tight Low Stretch Spanning Trees},
author={Ittai Abraham, Yair Bartal, and Ofer Neiman},
journal={arXiv preprint arXiv:0808.2017},
year={2008},
archivePrefix={arXiv},
eprint={0808.2017},
primaryClass={cs.DS cs.DM}
} | abraham2008nearly |
arxiv-4568 | 0808.2045 | Correctness is not enough | <|reference_start|>Correctness is not enough: The usual aim of spreadsheet audit is to verify correctness. There are two problems with this: first, it is often difficult to tell whether the spreadsheets in question are correct, and second, even if they are, they may still give the wrong results. These problems are explained in this paper, which presents the key criteria for judging a spreadsheet and discusses how those criteria can be achieved<|reference_end|> | arxiv | @article{pryor2008correctness,
title={Correctness is not enough},
author={Louise Pryor},
journal={Proc. European Spreadsheet Risks Int. Grp. (EuSpRIG) 2003 117-122
ISBN 1 86166 199 1},
year={2008},
archivePrefix={arXiv},
eprint={0808.2045},
primaryClass={cs.SE cs.HC}
} | pryor2008correctness |
arxiv-4569 | 0808.2059 | Diversity-Multiplexing Tradeoffs in MIMO Relay Channels | <|reference_start|>Diversity-Multiplexing Tradeoffs in MIMO Relay Channels: A multi-hop relay channel with multiple antenna terminals in a quasi-static slow fading environment is considered. For both full-duplex and half-duplex relays the fundamental diversity-multiplexing tradeoff (DMT) is analyzed. It is shown that, while decode-and-forward (DF) relaying achieves the optimal DMT in the full-duplex relay scenario, the dynamic decode-and-forward (DDF) protocol is needed to achieve the optimal DMT if the relay is constrained to half-duplex operation. For the latter case, static protocols are considered as well, and the corresponding achievable DMT performance is characterized.<|reference_end|> | arxiv | @article{gunduz2008diversity-multiplexing,
title={Diversity-Multiplexing Tradeoffs in MIMO Relay Channels},
author={Deniz Gunduz, Andrea Goldsmith, H. Vincent Poor},
journal={arXiv preprint arXiv:0808.2059},
year={2008},
doi={10.1109/GLOCOM.2008.ECP.194},
archivePrefix={arXiv},
eprint={0808.2059},
primaryClass={cs.IT math.IT}
} | gunduz2008diversity-multiplexing |
arxiv-4570 | 0808.2073 | Lower Bounds on the Rate-Distortion Function of LDGM Codes | <|reference_start|>Lower Bounds on the Rate-Distortion Function of LDGM Codes: A recent line of work has focused on the use of low-density generator matrix (LDGM) codes for lossy source coding. In this paper, wedevelop a generic technique for deriving lower bounds on the rate-distortion functions of binary linear codes, with particular interest on the effect of bounded degrees. The underlying ideas can be viewing as the source coding analog of the classical result of Gallager, providing bounds for channel coding over the binary symmetric channel using bounded degree LDPC codes. We illustrate this method for different random ensembles of LDGM codes, including the check-regular ensemble and bit-check-regular ensembles, by deriving explicit lower bounds on their rate-distortion performance as a function of the degrees.<|reference_end|> | arxiv | @article{dimakis2008lower,
title={Lower Bounds on the Rate-Distortion Function of LDGM Codes},
author={A. G. Dimakis, M. J. Wainwright, K. Ramchandran},
journal={arXiv preprint arXiv:0808.2073},
year={2008},
archivePrefix={arXiv},
eprint={0808.2073},
primaryClass={cs.IT math.IT}
} | dimakis2008lower |
arxiv-4571 | 0808.2081 | Concurrent Imitation Dynamics in Congestion Games | <|reference_start|>Concurrent Imitation Dynamics in Congestion Games: Imitating successful behavior is a natural and frequently applied approach to trust in when facing scenarios for which we have little or no experience upon which we can base our decision. In this paper, we consider such behavior in atomic congestion games. We propose to study concurrent imitation dynamics that emerge when each player samples another player and possibly imitates this agents' strategy if the anticipated latency gain is sufficiently large. Our main focus is on convergence properties. Using a potential function argument, we show that our dynamics converge in a monotonic fashion to stable states. In such a state none of the players can improve its latency by imitating somebody else. As our main result, we show rapid convergence to approximate equilibria. At an approximate equilibrium only a small fraction of agents sustains a latency significantly above or below average. In particular, imitation dynamics behave like fully polynomial time approximation schemes (FPTAS). Fixing all other parameters, the convergence time depends only in a logarithmic fashion on the number of agents. Since imitation processes are not innovative they cannot discover unused strategies. Furthermore, strategies may become extinct with non-zero probability. For the case of singleton games, we show that the probability of this event occurring is negligible. Additionally, we prove that the social cost of a stable state reached by our dynamics is not much worse than an optimal state in singleton congestion games with linear latency function. Finally, we discuss how the protocol can be extended such that, in the long run, dynamics converge to a Nash equilibrium.<|reference_end|> | arxiv | @article{ackermann2008concurrent,
title={Concurrent Imitation Dynamics in Congestion Games},
author={Heiner Ackermann, Petra Berenbrink, Simon Fischer, Martin Hoefer},
journal={arXiv preprint arXiv:0808.2081},
year={2008},
archivePrefix={arXiv},
eprint={0808.2081},
primaryClass={cs.GT}
} | ackermann2008concurrent |
arxiv-4572 | 0808.2083 | Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap Indexes | <|reference_start|>Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap Indexes: Bitmap indexes must be compressed to reduce input/output costs and minimize CPU usage. To accelerate logical operations (AND, OR, XOR) over bitmaps, we use techniques based on run-length encoding (RLE), such as Word-Aligned Hybrid (WAH) compression. These techniques are sensitive to the order of the rows: a simple lexicographical sort can divide the index size by 9 and make indexes several times faster. We investigate reordering heuristics based on computed attribute-value histograms. Simply permuting the columns of the table based on these histograms can increase the sorting efficiency by 40%.<|reference_end|> | arxiv | @article{kaser2008histogram-aware,
title={Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap
Indexes},
author={Owen Kaser, Daniel Lemire, Kamel Aouiche},
journal={arXiv preprint arXiv:0808.2083},
year={2008},
archivePrefix={arXiv},
eprint={0808.2083},
primaryClass={cs.DB}
} | kaser2008histogram-aware |
arxiv-4573 | 0808.2089 | Capacity-achieving Feedback Scheme for Gaussian Finite-State Markov Channels with Channel State Information | <|reference_start|>Capacity-achieving Feedback Scheme for Gaussian Finite-State Markov Channels with Channel State Information: In this paper, we propose capacity-achieving communication schemes for Gaussian finite-state Markov channels (FSMCs) subject to an average channel input power constraint, under the assumption that the transmitters can have access to delayed noiseless output feedback as well as instantaneous or delayed channel state information (CSI). We show that the proposed schemes reveals connections between feedback communication and feedback control.<|reference_end|> | arxiv | @article{liu2008capacity-achieving,
title={Capacity-achieving Feedback Scheme for Gaussian Finite-State Markov
Channels with Channel State Information},
author={Jialing Liu, Nicola Elia, and Sekhar Tatikonda},
journal={arXiv preprint arXiv:0808.2089},
year={2008},
doi={10.1109/TIT.2015.2437380},
archivePrefix={arXiv},
eprint={0808.2089},
primaryClass={cs.IT math.IT}
} | liu2008capacity-achieving |
arxiv-4574 | 0808.2092 | On zero-rate error exponent for BSC with noisy feedback | <|reference_start|>On zero-rate error exponent for BSC with noisy feedback: For the information transmission a binary symmetric channel is used. There is also another noisy binary symmetric channel (feedback channel), and the transmitter observes without delay all the outputs of the forward channel via that feedback channel. The transmission of a nonexponential number of messages (i.e. the transmission rate equals zero) is considered. The achievable decoding error exponent for such a combination of channels is investigated. It is shown that if the crossover probability of the feedback channel is less than a certain positive value, then the achievable error exponent is better than the similar error exponent of the no-feedback channel. The transmission method described and the corresponding lower bound for the error exponent can be strengthened, and also extended to the positive transmission rates.<|reference_end|> | arxiv | @article{burnashev2008on,
title={On zero-rate error exponent for BSC with noisy feedback},
author={Marat V. Burnashev and Hirosuke Yamamoto},
journal={Problems of Information Transmission, vol. 44, no. 3, pp. 33-49,
2008},
year={2008},
archivePrefix={arXiv},
eprint={0808.2092},
primaryClass={cs.IT math.IT}
} | burnashev2008on |
arxiv-4575 | 0808.2181 | Spectrum Sharing Between Cellular and Mobile Ad Hoc Networks: Transmission-Capacity Trade-Off | <|reference_start|>Spectrum Sharing Between Cellular and Mobile Ad Hoc Networks: Transmission-Capacity Trade-Off: Spectrum sharing between wireless networks improves the efficiency of spectrum usage, and thereby alleviates spectrum scarcity due to growing demands for wireless broadband access. To improve the usual underutilization of the cellular uplink spectrum, this paper studies spectrum sharing between a cellular uplink and a mobile ad hoc networks. These networks access either all frequency sub-channels or their disjoint sub-sets, called spectrum underlay and spectrum overlay, respectively. Given these spectrum sharing methods, the capacity trade-off between the coexisting networks is analyzed based on the transmission capacity of a network with Poisson distributed transmitters. This metric is defined as the maximum density of transmitters subject to an outage constraint for a given signal-to-interference ratio (SIR). Using tools from stochastic geometry, the transmission-capacity trade-off between the coexisting networks is analyzed, where both spectrum overlay and underlay as well as successive interference cancelation (SIC) are considered. In particular, for small target outage probability, the transmission capacities of the coexisting networks are proved to satisfy a linear equation, whose coefficients depend on the spectrum sharing method and whether SIC is applied. This linear equation shows that spectrum overlay is more efficient than spectrum underlay. Furthermore, this result also provides insight into the effects of different network parameters on transmission capacities, including link diversity gains, transmission distances, and the base station density. In particular, SIC is shown to increase transmission capacities of both coexisting networks by a linear factor, which depends on the interference-power threshold for qualifying canceled interferers.<|reference_end|> | arxiv | @article{huang2008spectrum,
title={Spectrum Sharing Between Cellular and Mobile Ad Hoc Networks:
Transmission-Capacity Trade-Off},
author={Kaibin Huang, Vincent K. N. Lau, Yan Chen},
journal={arXiv preprint arXiv:0808.2181},
year={2008},
archivePrefix={arXiv},
eprint={0808.2181},
primaryClass={cs.IT math.IT}
} | huang2008spectrum |
arxiv-4576 | 0808.2220 | Every Computably Enumerable Random Real Is Provably Computably Enumerable Random | <|reference_start|>Every Computably Enumerable Random Real Is Provably Computably Enumerable Random: We prove that every computably enumerable (c.e.) random real is provable in Peano Arithmetic (PA) to be c.e. random. A major step in the proof is to show that the theorem stating that "a real is c.e. and random iff it is the halting probability of a universal prefix-free Turing machine" can be proven in PA. Our proof, which is simpler than the standard one, can also be used for the original theorem. Our positive result can be contrasted with the case of computable functions, where not every computable function is provably computable in PA, or even more interestingly, with the fact that almost all random finite strings are not provably random in PA. We also prove two negative results: a) there exists a universal machine whose universality cannot be proved in PA, b) there exists a universal machine $U$ such that, based on $U$, PA cannot prove the randomness of its halting probability. The paper also includes a sharper form of the Kraft-Chaitin Theorem, as well as a formal proof of this theorem written with the proof assistant Isabelle.<|reference_end|> | arxiv | @article{calude2008every,
title={Every Computably Enumerable Random Real Is Provably Computably
Enumerable Random},
author={Cristian S. Calude, Nicholas J. Hay},
journal={arXiv preprint arXiv:0808.2220},
year={2008},
number={CDMTCS Research Report 328, 2008},
archivePrefix={arXiv},
eprint={0808.2220},
primaryClass={cs.CC cs.LO math.LO}
} | calude2008every |
arxiv-4577 | 0808.2222 | Better Bounds for Frequency Moments in Random-Order Streams | <|reference_start|>Better Bounds for Frequency Moments in Random-Order Streams: Estimating frequency moments of data streams is a very well studied problem and tight bounds are known on the amount of space that is necessary and sufficient when the stream is adversarially ordered. Recently, motivated by various practical considerations and applications in learning and statistics, there has been growing interest into studying streams that are randomly ordered. In the paper we improve the previous lower bounds on the space required to estimate the frequency moments of a randomly ordered streams.<|reference_end|> | arxiv | @article{andoni2008better,
title={Better Bounds for Frequency Moments in Random-Order Streams},
author={Alexandr Andoni, Andrew McGregor, Krzysztof Onak, Rina Panigrahy},
journal={arXiv preprint arXiv:0808.2222},
year={2008},
archivePrefix={arXiv},
eprint={0808.2222},
primaryClass={cs.DS}
} | andoni2008better |
arxiv-4578 | 0808.2227 | Higher Order Moments Generation by Mellin Transform for Compound Models of Clutter | <|reference_start|>Higher Order Moments Generation by Mellin Transform for Compound Models of Clutter: The compound models of clutter statistics are found suitable to describe the nonstationary nature of radar backscattering from high-resolution observations. In this letter, we show that the properties of Mellin transform can be utilized to generate higher order moments of simple and compound models of clutter statistics in a compact manner.<|reference_end|> | arxiv | @article{bhattacharya2008higher,
title={Higher Order Moments Generation by Mellin Transform for Compound Models
of Clutter},
author={C Bhattacharya},
journal={arXiv preprint arXiv:0808.2227},
year={2008},
archivePrefix={arXiv},
eprint={0808.2227},
primaryClass={cs.CV}
} | bhattacharya2008higher |
arxiv-4579 | 0808.2246 | Comparing human and automatic thesaurus mapping approaches in the agricultural domain | <|reference_start|>Comparing human and automatic thesaurus mapping approaches in the agricultural domain: Knowledge organization systems (KOS), like thesauri and other controlled vocabularies, are used to provide subject access to information systems across the web. Due to the heterogeneity of these systems, mapping between vocabularies becomes crucial for retrieving relevant information. However, mapping thesauri is a laborious task, and thus big efforts are being made to automate the mapping process. This paper examines two mapping approaches involving the agricultural thesaurus AGROVOC, one machine-created and one human created. We are addressing the basic question "What are the pros and cons of human and automatic mapping and how can they complement each other?" By pointing out the difficulties in specific cases or groups of cases and grouping the sample into simple and difficult types of mappings, we show the limitations of current automatic methods and come up with some basic recommendations on what approach to use when.<|reference_end|> | arxiv | @article{lauser2008comparing,
title={Comparing human and automatic thesaurus mapping approaches in the
agricultural domain},
author={Boris Lauser, Gudrun Johannsen, Caterina Caracciolo, Johannes Keizer,
Willem Robert van Hage, Philipp Mayr},
journal={arXiv preprint arXiv:0808.2246},
year={2008},
doi={10.18452/1251},
archivePrefix={arXiv},
eprint={0808.2246},
primaryClass={cs.DL}
} | lauser2008comparing |
arxiv-4580 | 0808.2296 | Fixed-Point Design of Generalized Comb Filters: A Statistical Approach | <|reference_start|>Fixed-Point Design of Generalized Comb Filters: A Statistical Approach: This paper is concerned with the problem of designing computationally efficient Generalized Comb Filters (GCF). Basically, GCF filters are anti-aliasing filters that guarantee superior performance in terms of selectivity and quantization noise rejection compared to classical comb filters, when used as decimation filters in multistage architectures. Upon employing a partial polyphase (PP) architecture proposed in a companion paper, we develop a sensitivity analysis in order to investigate the effects of the coefficients' quantization on the frequency response of the designed filters. We show that the sensitivity of the filter response to errors in the coefficients is dependent on the particular split of the decimation factor between the two sub-filters constituting the PP architecture. The sensitivity analysis is then used for developing a fixed-point implementation of a sample filter from the class of GCF filters, used as reference filter throughout the paper. Finally, we present computer simulations in order to evaluate the performance of the designed fixed-point filters.<|reference_end|> | arxiv | @article{laddomada2008fixed-point,
title={Fixed-Point Design of Generalized Comb Filters: A Statistical Approach},
author={Massimiliano Laddomada},
journal={arXiv preprint arXiv:0808.2296},
year={2008},
archivePrefix={arXiv},
eprint={0808.2296},
primaryClass={cs.OH}
} | laddomada2008fixed-point |
arxiv-4581 | 0808.2314 | Capacity of Symmetric K-User Gaussian Very Strong Interference Channels | <|reference_start|>Capacity of Symmetric K-User Gaussian Very Strong Interference Channels: This paper studies a symmetric K user Gaussian interference channel with K transmitters and K receivers. A "very strong" interference regime is derived for this channel setup. A "very strong" interference regime is one where the capacity region of the interference channel is the same as the capacity region of the channel with no interference. In this regime, the interference can be perfectly canceled by all the receivers without incurring any rate penalties. A "very strong" interference condition for an example symmetric K user deterministic interference channel is also presented.<|reference_end|> | arxiv | @article{sridharan2008capacity,
title={Capacity of Symmetric K-User Gaussian Very Strong Interference Channels},
author={Sriram Sridharan, Amin Jafarian, Sriram Vishwanath and Syed A. Jafar},
journal={arXiv preprint arXiv:0808.2314},
year={2008},
archivePrefix={arXiv},
eprint={0808.2314},
primaryClass={cs.IT math.IT}
} | sridharan2008capacity |
arxiv-4582 | 0808.2325 | Networking in the Physical World | <|reference_start|>Networking in the Physical World: In this work we propose a network meta-architecture based on fundamental laws of physics and a physical model of computation. This meta-architecture may be used to frame discussions about novel network architectures as well as cross-layer alterations to the canonical network stack.<|reference_end|> | arxiv | @article{neufeld2008networking,
title={Networking in the Physical World},
author={Michael Neufeld and Craig Partridge},
journal={arXiv preprint arXiv:0808.2325},
year={2008},
archivePrefix={arXiv},
eprint={0808.2325},
primaryClass={cs.NI}
} | neufeld2008networking |
arxiv-4583 | 0808.2417 | On NFAs Where All States are Final, Initial, or Both | <|reference_start|>On NFAs Where All States are Final, Initial, or Both: We examine questions involving nondeterministic finite automata where all states are final, initial, or both initial and final. First, we prove hardness results for the nonuniversality and inequivalence problems for these NFAs. Next, we characterize the languages accepted. Finally, we discuss some state complexity problems involving such automata.<|reference_end|> | arxiv | @article{kao2008on,
title={On NFAs Where All States are Final, Initial, or Both},
author={Jui-Yi Kao, Narad Rampersad, and Jeffrey Shallit},
journal={arXiv preprint arXiv:0808.2417},
year={2008},
archivePrefix={arXiv},
eprint={0808.2417},
primaryClass={cs.CC cs.FL}
} | kao2008on |
arxiv-4584 | 0808.2428 | Author-choice open access publishing in the biological and medical literature: a citation analysis | <|reference_start|>Author-choice open access publishing in the biological and medical literature: a citation analysis: In this article, we analyze the citations to articles published in 11 biological and medical journals from 2003 to 2007 that employ author-choice open access models. Controlling for known explanatory predictors of citations, only 2 of the 11 journals show positive and significant open access effects. Analyzing all journals together, we report a small but significant increase in article citations of 17%. In addition, there is strong evidence to suggest that the open access advantage is declining by about 7% per year, from 32% in 2004 to 11% in 2007.<|reference_end|> | arxiv | @article{davis2008author-choice,
title={Author-choice open access publishing in the biological and medical
literature: a citation analysis},
author={Philip M. Davis},
journal={JASIST, 60(1):3-8, 2008},
year={2008},
doi={10.1002/asi.20965},
archivePrefix={arXiv},
eprint={0808.2428},
primaryClass={cs.DL}
} | davis2008author-choice |
arxiv-4585 | 0808.2431 | A Simple E-Voting Protocol | <|reference_start|>A Simple E-Voting Protocol: We propose an e-voting protocol that seems to allow citizens to verify that their vote has been accurately taken into account while preserving its secrecy, without requiring the use of a complex process. The main idea is to give each voter a receipt on which her choice is mixed with the choices of other voters.<|reference_end|> | arxiv | @article{connes2008a,
title={A Simple E-Voting Protocol},
author={Frederic Connes},
journal={arXiv preprint arXiv:0808.2431},
year={2008},
archivePrefix={arXiv},
eprint={0808.2431},
primaryClass={cs.CY}
} | connes2008a |
arxiv-4586 | 0808.2486 | Wet Paper Coding for Watermarking of Binary Images | <|reference_start|>Wet Paper Coding for Watermarking of Binary Images: We propose a new method to embed data in binary images, including scanned text, figures, and signatures. Our method relies on the concept of wet paper codes. The shuffling before embedding is used in order to equalize irregular embedding capacity from diverse areas in the image. The hidden data can be extracted without the original binary image. We illustrate some examples of watermarked binary images after wet paper coding.<|reference_end|> | arxiv | @article{zubarev2008wet,
title={Wet Paper Coding for Watermarking of Binary Images},
author={Michail Zubarev, Valery Korzhik and Guillermo Morales-Luna},
journal={arXiv preprint arXiv:0808.2486},
year={2008},
archivePrefix={arXiv},
eprint={0808.2486},
primaryClass={cs.IT cs.CR math.IT}
} | zubarev2008wet |
arxiv-4587 | 0808.2515 | Provably efficient instanton search algorithm for LP decoding of LDPC codes over the BSC | <|reference_start|>Provably efficient instanton search algorithm for LP decoding of LDPC codes over the BSC: We consider Linear Programming (LP) decoding of a fixed Low-Density Parity-Check (LDPC) code over the Binary Symmetric Channel (BSC). The LP decoder fails when it outputs a pseudo-codeword which is not a codeword. We design an efficient algorithm termed the Instanton Search Algorithm (ISA) which, given a random input, generates a set of flips called the BSC-instanton. We prove that: (a) the LP decoder fails for any set of flips with support vector including an instanton; (b) for any input, the algorithm outputs an instanton in the number of steps upper-bounded by twice the number of flips in the input. Repeated sufficient number of times, the ISA outcomes the number of unique instantons of different sizes.<|reference_end|> | arxiv | @article{chilappagari2008provably,
title={Provably efficient instanton search algorithm for LP decoding of LDPC
codes over the BSC},
author={Shashi Kiran Chilappagari, Michael Chertkov and Bane Vasic},
journal={arXiv preprint arXiv:0808.2515},
year={2008},
number={LA-UR-08-05304},
archivePrefix={arXiv},
eprint={0808.2515},
primaryClass={cs.IT cond-mat.stat-mech math.IT}
} | chilappagari2008provably |
arxiv-4588 | 0808.2530 | Fair Scheduling in Networks Through Packet Election | <|reference_start|>Fair Scheduling in Networks Through Packet Election: We consider the problem of designing a fair scheduling algorithm for discrete-time constrained queuing networks. Each queue has dedicated exogenous packet arrivals. There are constraints on which queues can be served simultaneously. This model effectively describes important special instances like network switches, interference in wireless networks, bandwidth sharing for congestion control and traffic scheduling in road roundabouts. Fair scheduling is required because it provides isolation to different traffic flows; isolation makes the system more robust and enables providing quality of service. Existing work on fairness for constrained networks concentrates on flow based fairness. As a main result, we describe a notion of packet based fairness by establishing an analogy with the ranked election problem: packets are voters, schedules are candidates and each packet ranks the schedules based on its priorities. We then obtain a scheduling algorithm that achieves the described notion of fairness by drawing upon the seminal work of Goodman and Markowitz (1952). This yields the familiar Maximum Weight (MW) style algorithm. As another important result we prove that algorithm obtained is throughput optimal. There is no reason a priori why this should be true, and the proof requires non-traditional methods.<|reference_end|> | arxiv | @article{jagabathula2008fair,
title={Fair Scheduling in Networks Through Packet Election},
author={Srikanth Jagabathula, Devavrat Shah},
journal={arXiv preprint arXiv:0808.2530},
year={2008},
doi={10.1109/TIT.2010.2103851},
archivePrefix={arXiv},
eprint={0808.2530},
primaryClass={cs.IT math.IT}
} | jagabathula2008fair |
arxiv-4589 | 0808.2543 | A Refined Difference Field Theory for Symbolic Summation | <|reference_start|>A Refined Difference Field Theory for Symbolic Summation: In this article we present a refined summation theory based on Karr's difference field approach. The resulting algorithms find sum representations with optimal nested depth. For instance, the algorithms have been applied successively to evaluate Feynman integrals from Perturbative Quantum Field Theory.<|reference_end|> | arxiv | @article{schneider2008a,
title={A Refined Difference Field Theory for Symbolic Summation},
author={Carsten Schneider},
journal={J. Symbolic Comput. 43(9), pp. 611-644. 2008},
year={2008},
doi={10.1016/j.jsc.2008.01.001},
number={SFB F013, J. Kepler University Linz. Technical report no. 2007-24},
archivePrefix={arXiv},
eprint={0808.2543},
primaryClass={cs.SC math-ph math.CO math.MP}
} | schneider2008a |
arxiv-4590 | 0808.2544 | Morphic and Automatic Words: Maximal Blocks and Diophantine Approximation | <|reference_start|>Morphic and Automatic Words: Maximal Blocks and Diophantine Approximation: Let $\mb w$ be a morphic word over a finite alphabet $\Sigma$, and let $\Delta$ be a nonempty subset of $\Sigma$. We study the behavior of maximal blocks consisting only of letters from $\Delta$ in $\mb w$, and prove the following: let $(i_k,j_k)$ denote the starting and ending positions, respectively, of the $k$'th maximal $\Delta$-block in $\mb w$. Then $\limsup_{k\to\infty} (j_k/i_k)$ is algebraic if $\mb w$ is morphic, and rational if $\mb w$ is automatic. As a result, we show that the same conclusion holds if $(i_k,j_k)$ are the starting and ending positions of the $k$'th maximal zero block, and, more generally, of the $k$'th maximal $x$-block, where $x$ is an arbitrary word. This enables us to draw conclusions about the irrationality exponent of automatic and morphic numbers. In particular, we show that the irrationality exponent of automatic (resp., morphic) numbers belonging to a certain class that we define is rational (resp., algebraic).<|reference_end|> | arxiv | @article{bugeaud2008morphic,
title={Morphic and Automatic Words: Maximal Blocks and Diophantine
Approximation},
author={Yann Bugeaud, Dalia Krieger, Jeffrey Shallit},
journal={arXiv preprint arXiv:0808.2544},
year={2008},
archivePrefix={arXiv},
eprint={0808.2544},
primaryClass={math.CO cs.FL}
} | bugeaud2008morphic |
arxiv-4591 | 0808.2548 | Negative Beta Encoder | <|reference_start|>Negative Beta Encoder: A new class of analog-to-digital (A/D) and digital-to-analog (D/A) converters using a flaky quantiser, called the $\beta$-encoder, has been shown to have exponential bit rate accuracy while possessing a self-correction property for fluctuations of the amplifier factor $\beta$ and the quantiser threshold $\nu$. The probabilistic behavior of such a flaky quantiser is explained as the deterministic dynamics of the multi-valued R\'enyi map. That is, a sample $x$ is always confined to a contracted subinterval while successive approximations of $x$ are performed using $\beta$-expansion even if $\nu$ may vary at each iteration. This viewpoint enables us to get the decoded sample, which is equal to the midpoint of the subinterval, and its associated characteristic equation for recovering $\beta$ which improves the quantisation error by more than $3{dB}$ when $\beta>1.5$. The invariant subinterval under the R\'enyi map shows that $\nu$ should be set to around the midpoint of its associated greedy and lazy values. %in terms of its quantisation MSE (mean square error). Furthermore, a new A/D converter is introduced called the negative $\beta$-encoder, which further improves the quantisation error of the $\beta$-encoder. A two-state Markov chain describing the $\beta$-encoder suggests that a negative eigenvalue of its associated transition probability matrix reduces the quantisation error.<|reference_end|> | arxiv | @article{kohda2008negative,
title={Negative Beta Encoder},
author={Tohru Kohda, Satoshi Hironaka, and Kazuyuki Aihara},
journal={arXiv preprint arXiv:0808.2548},
year={2008},
archivePrefix={arXiv},
eprint={0808.2548},
primaryClass={cs.IT math.IT}
} | kohda2008negative |
arxiv-4592 | 0808.2562 | Spectrum Sensing Algorithms for Cognitive Radio Based on Statistical Covariances | <|reference_start|>Spectrum Sensing Algorithms for Cognitive Radio Based on Statistical Covariances: Spectrum sensing, i.e., detecting the presence of primary users in a licensed spectrum, is a fundamental problem in cognitive radio. Since the statistical covariances of received signal and noise are usually different, they can be used to differentiate the case where the primary user's signal is present from the case where there is only noise. In this paper, spectrum sensing algorithms are proposed based on the sample covariance matrix calculated from a limited number of received signal samples. Two test statistics are then extracted from the sample covariance matrix. A decision on the signal presence is made by comparing the two test statistics. Theoretical analysis for the proposed algorithms is given. Detection probability and associated threshold are found based on statistical theory. The methods do not need any information of the signal, the channel and noise power a priori. Also, no synchronization is needed. Simulations based on narrowband signals, captured digital television (DTV) signals and multiple antenna signals are presented to verify the methods.<|reference_end|> | arxiv | @article{zeng2008spectrum,
title={Spectrum Sensing Algorithms for Cognitive Radio Based on Statistical
Covariances},
author={Yonghong Zeng and Ying-Chang Liang},
journal={arXiv preprint arXiv:0808.2562},
year={2008},
archivePrefix={arXiv},
eprint={0808.2562},
primaryClass={cs.IT math.IT}
} | zeng2008spectrum |
arxiv-4593 | 0808.2584 | On Transformations of Load-Store Maurer Instruction Set Architecture | <|reference_start|>On Transformations of Load-Store Maurer Instruction Set Architecture: In this paper, we study how certain conditions can affect the transformations on the states of the memory of a strict load-store Maurer ISA, when half of the data memory serves as the part of the operating unit.<|reference_end|> | arxiv | @article{hou2008on,
title={On Transformations of Load-Store Maurer Instruction Set Architecture},
author={Tie Hou},
journal={arXiv preprint arXiv:0808.2584},
year={2008},
archivePrefix={arXiv},
eprint={0808.2584},
primaryClass={cs.AR}
} | hou2008on |
arxiv-4594 | 0808.2586 | Towards Provable Secure Neighbor Discovery in Wireless Networks | <|reference_start|>Towards Provable Secure Neighbor Discovery in Wireless Networks: In wireless systems, neighbor discovery (ND) is a fundamental building block: determining which devices are within direct radio communication is an enabler for networking protocols and a wide range of applications. To thwart abuse of ND and the resultant compromise of the dependent functionality of wireless systems, numerous works proposed solutions to secure ND. Nonetheless, until very recently, there has been no formal analysis of secure ND protocols. We close this gap in \cite{asiaccs08}, but we concentrate primarily on the derivation of an impossibility result for a class of protocols. In this paper, we focus on reasoning about specific protocols. First, we contribute a number of extensions and refinements on the framework of [24]. As we are particularly concerned with the practicality of provably secure ND protocols, we investigate availability and redefine accordingly the ND specification, and also consider composability of ND with other protocols. Then, we propose and analyze two secure ND protocols: We revisit one of the protocols analyzed in [24], and introduce and prove correct a more elaborate challenge-response protocol.<|reference_end|> | arxiv | @article{poturalski2008towards,
title={Towards Provable Secure Neighbor Discovery in Wireless Networks},
author={Marcin Poturalski, Panos Papadimitratos, Jean-Pierre Hubaux},
journal={ACM Computer and Communications Security Conference (CCS) Sixth
Workshop on Formal Methods in Security Engineering (FMSE), pages 31{42,
Alexan- dria, VA, USA, October 2008},
year={2008},
archivePrefix={arXiv},
eprint={0808.2586},
primaryClass={cs.CR cs.NI}
} | poturalski2008towards |
arxiv-4595 | 0808.2591 | GossiCrypt: Wireless Sensor Network Data Confidentiality Against Parasitic Adversaries | <|reference_start|>GossiCrypt: Wireless Sensor Network Data Confidentiality Against Parasitic Adversaries: Resource and cost constraints remain a challenge for wireless sensor network security. In this paper, we propose a new approach to protect confidentiality against a parasitic adversary, which seeks to exploit sensor networks by obtaining measurements in an unauthorized way. Our low-complexity solution, GossiCrypt, leverages on the large scale of sensor networks to protect confidentiality efficiently and effectively. GossiCrypt protects data by symmetric key encryption at their source nodes and re-encryption at a randomly chosen subset of nodes en route to the sink. Furthermore, it employs key refreshing to mitigate the physical compromise of cryptographic keys. We validate GossiCrypt analytically and with simulations, showing it protects data confidentiality with probability almost one. Moreover, compared with a system that uses public-key data encryption, the energy consumption of GossiCrypt is one to three orders of magnitude lower.<|reference_end|> | arxiv | @article{luo2008gossicrypt:,
title={GossiCrypt: Wireless Sensor Network Data Confidentiality Against
Parasitic Adversaries},
author={Jun Luo, Panos Papadimitratos and Jean-Pierre Hubaux},
journal={Proceedings of the Fifth IEEE-CS Conference on Sensor, Mesh and Ad
Hoc Communi- cations and Networks (IEEE SECON), pages 441{450, San Francisco,
CA, USA, June 2008},
year={2008},
doi={10.1109/SAHCN.2008.60},
archivePrefix={arXiv},
eprint={0808.2591},
primaryClass={cs.CR cs.NI}
} | luo2008gossicrypt: |
arxiv-4596 | 0808.2596 | Parameterized Telescoping Proves Algebraic Independence of Sums | <|reference_start|>Parameterized Telescoping Proves Algebraic Independence of Sums: Usually creative telescoping is used to derive recurrences for sums. In this article we show that the non-existence of a creative telescoping solution, and more generally, of a parameterized telescoping solution, proves algebraic independence of certain types of sums. Combining this fact with summation-theory shows transcendence of whole classes of sums. Moreover, this result throws new light on the question why, e.g., Zeilberger's algorithm fails to find a recurrence with minimal order.<|reference_end|> | arxiv | @article{schneider2008parameterized,
title={Parameterized Telescoping Proves Algebraic Independence of Sums},
author={Carsten Schneider},
journal={arXiv preprint arXiv:0808.2596},
year={2008},
number={SFB F013, J. Kepler University Linz. Technical report no. 2006-40,
2006},
archivePrefix={arXiv},
eprint={0808.2596},
primaryClass={cs.SC math.CO math.NT}
} | schneider2008parameterized |
arxiv-4597 | 0808.2602 | Easily testable logical networks based on a 'widened long flip-flop' | <|reference_start|>Easily testable logical networks based on a 'widened long flip-flop': The article describes an attempt to solve at once three basic problems arising at testing a complex digital equipment for defects: 1) the problem of an exponential increasing of the complexity of testing the equipment with the complexity of the equipment; 2) the problem of testing of the tester; 3) the problem of a mutual masking of defects. The proposed solution is nothing more than using certain limitations for connections between usual logical gates. Arbitrary multiple stuck-at-faults are supposed as defects.<|reference_end|> | arxiv | @article{stukach2008easily,
title={Easily testable logical networks based on a 'widened long flip-flop'},
author={Nick Stukach},
journal={arXiv preprint arXiv:0808.2602},
year={2008},
archivePrefix={arXiv},
eprint={0808.2602},
primaryClass={cs.AR}
} | stukach2008easily |
arxiv-4598 | 0808.2654 | Report on the "Secure Vehicular Communications: Results and Challenges Ahead" Workshop | <|reference_start|>Report on the "Secure Vehicular Communications: Results and Challenges Ahead" Workshop: This is a report and a collection of abstracts from the Feb. 2008 Lausanne Workshop on Secure Vehicular Communication Systems.<|reference_end|> | arxiv | @article{papadimitratos2008report,
title={Report on the "Secure Vehicular Communications: Results and Challenges
Ahead" Workshop},
author={Panos Papadimitratos and Jean-Pierre Hubaux},
journal={ACM SIGMOBILE Mobile Computing and Communications Review (MC2R),
12(2):53-64, April 2008},
year={2008},
archivePrefix={arXiv},
eprint={0808.2654},
primaryClass={cs.CR cs.NI}
} | papadimitratos2008report |
arxiv-4599 | 0808.2659 | Distributed Source Coding using Abelian Group Codes | <|reference_start|>Distributed Source Coding using Abelian Group Codes: In this work, we consider a distributed source coding problem with a joint distortion criterion depending on the sources and the reconstruction. This includes as a special case the problem of computing a function of the sources to within some distortion and also the classic Slepian-Wolf problem, Berger-Tung problem, Wyner-Ziv problem, Yeung-Berger problem and the Ahlswede-Korner-Wyner problem. While the prevalent trend in information theory has been to prove achievability results using Shannon's random coding arguments, using structured random codes offer rate gains over unstructured random codes for many problems. Motivated by this, we present a new achievable rate-distortion region for this problem for discrete memoryless sources based on "good" structured random nested codes built over abelian groups. We demonstrate rate gains for this problem over traditional coding schemes using random unstructured codes. For certain sources and distortion functions, the new rate region is strictly bigger than the Berger-Tung rate region, which has been the best known achievable rate region for this problem till now. Further, there is no known unstructured random coding scheme that achieves these rate gains. Achievable performance limits for single-user source coding using abelian group codes are also obtained as parts of the proof of the main coding theorem. As a corollary, we also prove that nested linear codes achieve the Shannon rate-distortion bound in the single-user setting.<|reference_end|> | arxiv | @article{krithivasan2008distributed,
title={Distributed Source Coding using Abelian Group Codes},
author={Dinesh Krithivasan and S. Sandeep Pradhan},
journal={arXiv preprint arXiv:0808.2659},
year={2008},
archivePrefix={arXiv},
eprint={0808.2659},
primaryClass={cs.IT math.IT}
} | krithivasan2008distributed |
arxiv-4600 | 0808.2662 | Multitask Efficiencies in the Decision Tree Model | <|reference_start|>Multitask Efficiencies in the Decision Tree Model: In Direct Sum problems [KRW], one tries to show that for a given computational model, the complexity of computing a collection of finite functions on independent inputs is approximately the sum of their individual complexities. In this paper, by contrast, we study the diversity of ways in which the joint computational complexity can behave when all the functions are evaluated on a common input. We focus on the deterministic decision tree model, with depth as the complexity measure; in this model we prove a result to the effect that the 'obvious' constraints on joint computational complexity are essentially the only ones. The proof uses an intriguing new type of cryptographic data structure called a `mystery bin' which we construct using a small polynomial separation between deterministic and unambiguous query complexity shown by Savicky. We also pose a variant of the Direct Sum Conjecture of [KRW] which, if proved for a single family of functions, could yield an analogous result for models such as the communication model.<|reference_end|> | arxiv | @article{drucker2008multitask,
title={Multitask Efficiencies in the Decision Tree Model},
author={Andrew Drucker},
journal={24th Annual IEEE Conference on Computational Complexity, 2009, p.
286-297},
year={2008},
doi={10.1109/CCC.2009.33},
archivePrefix={arXiv},
eprint={0808.2662},
primaryClass={cs.CC}
} | drucker2008multitask |
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