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0905.2479
A note on a complex Hilbert metric with application to domain of analyticity for entropy rate of hidden Markov processes
math.DS cs.IT math.IT
In this note, we show that small complex perturbations of positive matrices are contractions, with respect to a complex version of the Hilbert metric, on the standard complex simplex. We show that this metric can be used to obtain estimates of the domain of analyticity of entropy rate for a hidden Markov process when...
0905.2501
Macrodynamics of users' behavior in Information Retrieval
cs.IR
We present a method to geometrize massive data sets from search engines query logs. For this purpose, a macrodynamic-like quantitative model of the Information Retrieval (IR) process is developed, whose paradigm is inspired by basic constructions of Einstein's general relativity theory in which all IR objects are uni...
0905.2635
Point-Set Registration: Coherent Point Drift
cs.CV
Point set registration is a key component in many computer vision tasks. The goal of point set registration is to assign correspondences between two sets of points and to recover the transformation that maps one point set to the other. Multiple factors, including an unknown non-rigid spatial transformation, large dim...
0905.2638
Secure Degrees of Freedom for Gaussian Channels with Interference: Structured Codes Outperform Gaussian Signaling
cs.IT math.IT
In this work, we prove that a positive secure degree of freedom is achievable for a large class of Gaussian channels as long as the channel is not degraded and the channel is fully connected. This class includes the MAC wire-tap channel, the 2-user interference channel with confidential messages, the 2-user interfere...
0905.2639
Information-theoretic limits of selecting binary graphical models in high dimensions
cs.IT cs.LG math.IT math.ST stat.TH
The problem of graphical model selection is to correctly estimate the graph structure of a Markov random field given samples from the underlying distribution. We analyze the information-theoretic limitations of the problem of graph selection for binary Markov random fields under high-dimensional scaling, in which the...
0905.2640
The Gaussian Many-to-One Interference Channel with Confidential Messages
cs.IT math.IT
We investigate the $K$-user many-to-one interference channel with confidential messages in which the $K$th user experiences interference from all other $K-1$ users, and is at the same time treated as an eavesdropper to all the messages of these users. We derive achievable rates and an upper bound on the sum rate for ...
0905.2643
K-user Interference Channels: Achievable Secrecy Rate and Degrees of Freedom
cs.IT math.IT
In this work, we consider achievable secrecy rates for symmetric $K$-user ($K \ge 3$) interference channels with confidential messages. We find that nested lattice codes and layered coding are useful in providing secrecy for these channels. Achievable secrecy rates are derived for very strong interference. In additio...
0905.2645
Providing Secrecy with Lattice Codes
cs.IT math.IT
Recent results have shown that lattice codes can be used to construct good channel codes, source codes and physical layer network codes for Gaussian channels. On the other hand, for Gaussian channels with secrecy constraints, efforts to date rely on random codes. In this work, we provide a tool to bridge these two ar...
0905.2649
An Immune System Inspired Approach to Automated Program Verification
cs.NE
An immune system inspired Artificial Immune System (AIS) algorithm is presented, and is used for the purposes of automated program verification. Relevant immunological concepts are discussed and the field of AIS is briefly reviewed. It is proposed to use this AIS algorithm for a specific automated program verificatio...
0905.2657
Web 2.0 OLAP: From Data Cubes to Tag Clouds
cs.DB
Increasingly, business projects are ephemeral. New Business Intelligence tools must support ad-lib data sources and quick perusal. Meanwhile, tag clouds are a popular community-driven visualization technique. Hence, we investigate tag-cloud views with support for OLAP operations such as roll-ups, slices, dices, clust...
0905.2659
Coalitional Games for Distributed Collaborative Spectrum Sensing in Cognitive Radio Networks
cs.GT cs.IT math.IT
Collaborative spectrum sensing among secondary users (SUs) in cognitive networks is shown to yield a significant performance improvement. However, there exists an inherent trade off between the gains in terms of probability of detection of the primary user (PU) and the costs in terms of false alarm probability. In th...
0905.2676
On the Benefits of Bandwidth Limiting in Decentralized Vector Multiple Access Channels
cs.IT math.IT
We study the network spectral efficiency of decentralized vector multiple access channels (MACs) when the number of accessible dimensions per transmitter is strategically limited. Considering each dimension as a frequency band, we call this limiting process bandwidth limiting (BL). Assuming that each transmitter maxi...
0905.2718
Achievable Rate and Optimal Physical Layer Rate Allocation in Interference-Free Wireless Networks
cs.IT math.IT
We analyze the achievable rate in interference-free wireless networks with physical layer fading channels and orthogonal multiple access. As a starting point, the point-to-point channel is considered. We find the optimal physical and network layer rate trade-off which maximizes the achievable overall rate for both a ...
0905.2796
Sparse Network Coding with Overlapping Classes
cs.IT math.IT
This paper presents a novel approach to network coding for distribution of large files. Instead of the usual approach of splitting packets into disjoint classes (also known as generations) we propose the use of overlapping classes. The overlapping allows the decoder to alternate between Gaussian elimination and back ...
0905.2817
Cavity approach to the Sourlas code system
cond-mat.dis-nn cond-mat.stat-mech cs.IT math.IT
The statistical physics properties of regular and irregular Sourlas codes are investigated in this paper by the cavity method. At finite temperatures, the free energy density of these coding systems is derived and compared with the result obtained by the replica method. In the zero temperature limit, the Shannon's bo...
0905.2882
Do not Choose Representation just Change: An Experimental Study in States based EA
cs.NE cs.AI
Our aim in this paper is to analyse the phenotypic effects (evolvability) of diverse coding conversion operators in an instance of the states based evolutionary algorithm (SEA). Since the representation of solutions or the selection of the best encoding during the optimization process has been proved to be very impor...
0905.2919
Succinct Representation of Codes with Applications to Testing
cs.IT math.IT
Motivated by questions in property testing, we search for linear error-correcting codes that have the "single local orbit" property: i.e., they are specified by a single local constraint and its translations under the symmetry group of the code. We show that the dual of every "sparse" binary code whose coordinates ar...
0905.2924
Colorization of Natural Images via L1 Optimization
cs.CV
Natural images in the colour space YUV have been observed to have a non-Gaussian, heavy tailed distribution (called 'sparse') when the filter G(U)(r) = U(r) - sum_{s \in N(r)} w{(Y)_{rs}} U(s), is applied to the chromacity channel U (and equivalently to V), where w is a weighting function constructed from the intensi...
0905.2958
A statistical learning approach to color demosaicing
cs.CV
A statistical learning/inference framework for color demosaicing is presented. We start with simplistic assumptions about color constancy, and recast color demosaicing as a blind linear inverse problem: color parameterizes the unknown kernel, while brightness takes on the role of a latent variable. An expectation-max...
0905.2990
Automatic Summarization System coupled with a Question-Answering System (QAAS)
cs.IR cs.CL
To select the most relevant sentences of a document, it uses an optimal decision algorithm that combines several metrics. The metrics processes, weighting and extract pertinence sentences by statistical and informational algorithms. This technique might improve a Question-Answering system, whose function is to provid...
0905.2997
Average-Case Active Learning with Costs
cs.LG
We analyze the expected cost of a greedy active learning algorithm. Our analysis extends previous work to a more general setting in which different queries have different costs. Moreover, queries may have more than two possible responses and the distribution over hypotheses may be non uniform. Specific applications i...
0905.3023
Interference and Deployment Issues for Cognitive Radio Systems in Shadowing Environments
cs.IT math.IT
In this paper we describe a model for calculating the aggregate interference encountered by primary receivers in the presence of randomly placed cognitive radios (CRs). We show that incorporating the impact of distance attenuation and lognormal fading on each constituent interferer in the aggregate, leads to a compos...
0905.3030
Performance of Cognitive Radio Systems with Imperfect Radio Environment Map Information
cs.IT math.IT
In this paper we describe the effect of imperfections in the radio environment map (REM) information on the performance of cognitive radio (CR) systems. Via simulations we explore the relationship between the required precision of the REM and various channel/system properties. For example, the degree of spatial corre...
0905.3076
On a Class of Doubly-Generalized LDPC Codes with Single Parity-Check Variable Nodes
cs.IT math.IT
A class of doubly-generalized low-density parity-check (D-GLDPC) codes, where single parity-check (SPC) codes are used as variable nodes (VNs), is investigated. An expression for the growth rate of the weight distribution of any D-GLDPC ensemble with a uniform check node (CN) set is presented at first, together with ...
0905.3086
Deterministic Relay Networks with State Information
cs.IT math.IT
Motivated by fading channels and erasure channels, the problem of reliable communication over deterministic relay networks is studied, in which relay nodes receive a function of the incoming signals and a random network state. An achievable rate is characterized for the case in which destination nodes have full knowl...
0905.3108
A Note on the Complexity of the Satisfiability Problem for Graded Modal Logics
cs.LO cs.AI cs.CC
Graded modal logic is the formal language obtained from ordinary (propositional) modal logic by endowing its modal operators with cardinality constraints. Under the familiar possible-worlds semantics, these augmented modal operators receive interpretations such as "It is true at no fewer than 15 accessible worlds tha...
0905.3109
Interference Channels with Source Cooperation
cs.IT math.IT
The role of cooperation in managing interference - a fundamental feature of the wireless channel - is investigated by studying the two-user Gaussian interference channel where the source nodes can both transmit and receive in full-duplex. The sum-capacity of this channel is obtained within a gap of a constant number ...
0905.3135
The discrete logarithm problem in the group of non-singular circulant matrices
cs.CR cs.DM cs.IT math.IT
The discrete logarithm problem is one of the backbones in public key cryptography. In this paper we study the discrete logarithm problem in the group of circulant matrices over a finite field. This gives rise to secure and fast public key cryptosystems.
0905.3178
SQS-graphs of Solov'eva-Phelps codes
math.CO cs.IT math.IT
A binary extended 1-perfect code $\mathcal C$ folds over its kernel via the Steiner quadruple systems associated with its codewords. The resulting folding, proposed as a graph invariant for $\mathcal C$, distinguishes among the 361 nonlinear codes $\mathcal C$ of kernel dimension $\kappa$ obtained via Solov'eva-Phelp...
0905.3201
On the Statistics of Cognitive Radio Capacity in Shadowing and Fast Fading Environments
cs.IT math.IT
In this paper we consider the capacity of the cognitive radio channel in a fading environment under a "low interference regime". This capacity depends critically on a power loss parameter, $\alpha$, which governs how much transmit power the cognitive radio dedicates to relaying the primary message. We derive a simple...
0905.3245
Novel Algorithm for Sparse Solutions to Linear Inverse Problems with Multiple Measurements
cs.IT math.IT
In this report, a novel efficient algorithm for recovery of jointly sparse signals (sparse matrix) from multiple incomplete measurements has been presented, in particular, the NESTA-based MMV optimization method. In a nutshell, the jointly sparse recovery is obviously superior to applying standard sparse reconstructi...
0905.3318
An Object-Oriented and Fast Lexicon for Semantic Generation
cs.CL cs.DB cs.DS cs.IR cs.PL
This paper is about the technical design of a large computational lexicon, its storage, and its access from a Prolog environment. Traditionally, efficient access and storage of data structures is implemented by a relational database management system. In Delilah, a lexicon-based NLP system, efficient access to the le...
0905.3347
Information Distance in Multiples
cs.CV cs.LG
Information distance is a parameter-free similarity measure based on compression, used in pattern recognition, data mining, phylogeny, clustering, and classification. The notion of information distance is extended from pairs to multiples (finite lists). We study maximal overlap, metricity, universality, minimal overl...
0905.3356
Memento Ludi: Information Retrieval from a Game-Theoretic Perspective
cs.IR cs.GT
We develop a macro-model of information retrieval process using Game Theory as a mathematical theory of conflicts. We represent the participants of the Information Retrieval process as a game of two abstract players. The first player is the `intellectual crowd' of users of search engines, the second is a community of...
0905.3360
A Generalized Statistical Complexity Measure: Applications to Quantum Systems
quant-ph cs.IT math.IT nlin.AO physics.atom-ph
A two-parameter family of complexity measures $\tilde{C}^{(\alpha,\beta)}$ based on the R\'enyi entropies is introduced and characterized by a detailed study of its mathematical properties. This family is the generalization of a continuous version of the LMC complexity, which is recovered for $\alpha=1$ and $\beta=2$...
0905.3369
Learning Nonlinear Dynamic Models
cs.AI cs.LG
We present a novel approach for learning nonlinear dynamic models, which leads to a new set of tools capable of solving problems that are otherwise difficult. We provide theory showing this new approach is consistent for models with long range structure, and apply the approach to motion capture and high-dimensional v...
0905.3378
Interpretations of the Web of Data
cs.AI cs.DL
The emerging Web of Data utilizes the web infrastructure to represent and interrelate data. The foundational standards of the Web of Data include the Uniform Resource Identifier (URI) and the Resource Description Framework (RDF). URIs are used to identify resources and RDF is used to relate resources. While RDF has b...
0905.3407
Throughput and Delay Scaling in Supportive Two-Tier Networks
cs.IT math.IT
Consider a wireless network that has two tiers with different priorities: a primary tier vs. a secondary tier, which is an emerging network scenario with the advancement of cognitive radio technologies. The primary tier consists of randomly distributed legacy nodes of density $n$, which have an absolute priority to a...
0905.3428
Finding Anomalous Periodic Time Series: An Application to Catalogs of Periodic Variable Stars
cs.LG astro-ph.IM physics.data-an
Catalogs of periodic variable stars contain large numbers of periodic light-curves (photometric time series data from the astrophysics domain). Separating anomalous objects from well-known classes is an important step towards the discovery of new classes of astronomical objects. Most anomaly detection methods for tim...
0905.3434
Exploiting Opportunistic Multiuser Detection in Decentralized Multiuser MIMO Systems
cs.IT math.IT
This paper studies the design of a decentralized multiuser multi-antenna (MIMO) system for spectrum sharing over a fixed narrow band, where the coexisting users independently update their transmit covariance matrices for individual transmit-rate maximization via an iterative manner. This design problem was usually in...
0905.3436
On Active Learning and Supervised Transmission of Spectrum Sharing Based Cognitive Radios by Exploiting Hidden Primary Radio Feedback
cs.IT math.IT
This paper studies the wireless spectrum sharing between a pair of distributed primary radio (PR) and cognitive radio (CR) links. Assuming that the PR link adapts its transmit power and/or rate upon receiving an interference signal from the CR and such transmit adaptations are observable by the CR, this results in a ...
0905.3527
Quantum Annealing for Clustering
cond-mat.dis-nn cond-mat.stat-mech cs.LG quant-ph
This paper studies quantum annealing (QA) for clustering, which can be seen as an extension of simulated annealing (SA). We derive a QA algorithm for clustering and propose an annealing schedule, which is crucial in practice. Experiments show the proposed QA algorithm finds better clustering assignments than SA. Furt...
0905.3528
Quantum Annealing for Variational Bayes Inference
cond-mat.dis-nn cond-mat.stat-mech cs.LG quant-ph
This paper presents studies on a deterministic annealing algorithm based on quantum annealing for variational Bayes (QAVB) inference, which can be seen as an extension of the simulated annealing for variational Bayes (SAVB) inference. QAVB is as easy as SAVB to implement. Experiments revealed QAVB finds a better loca...
0905.3582
Profiling of a network behind an infectious disease outbreak
cs.AI q-bio.PE
Stochasticity and spatial heterogeneity are of great interest recently in studying the spread of an infectious disease. The presented method solves an inverse problem to discover the effectively decisive topology of a heterogeneous network and reveal the transmission parameters which govern the stochastic spreads ove...
0905.3587
Prediction, Retrodiction, and The Amount of Information Stored in the Present
cond-mat.stat-mech cond-mat.dis-nn cs.IT math.IT physics.data-an
We introduce an ambidextrous view of stochastic dynamical systems, comparing their forward-time and reverse-time representations and then integrating them into a single time-symmetric representation. The perspective is useful theoretically, computationally, and conceptually. Mathematically, we prove that the excess e...
0905.3602
Level Crossing Rates of Interference in Cognitive Radio Networks
cs.IT math.IT
The future deployment of cognitive radios is critically dependent on the fact that the incumbent primary user system must remain as oblivious as possible to their presence. This in turn heavily relies on the fluctuations of the interfering cognitive radio signals. In this letter we compute the level crossing rates of...
0905.3640
Coevolutionary Genetic Algorithms for Establishing Nash Equilibrium in Symmetric Cournot Games
cs.GT cs.LG
We use co-evolutionary genetic algorithms to model the players' learning process in several Cournot models, and evaluate them in terms of their convergence to the Nash Equilibrium. The "social-learning" versions of the two co-evolutionary algorithms we introduce, establish Nash Equilibrium in those models, in contras...
0905.3689
Optimized Training and Feedback for MIMO Downlink Channels
cs.IT math.IT
We consider a MIMO fading broadcast channel where channel state information is acquired at user terminals via downlink training and channel feedback is used to provide transmitter channel state information (CSIT) to the base station. The feedback channel (the corresponding uplink) is modeled as an AWGN channel, ortho...
0905.3720
Where are the really hard manipulation problems? The phase transition in manipulating the veto rule
cs.AI cs.CC
Voting is a simple mechanism to aggregate the preferences of agents. Many voting rules have been shown to be NP-hard to manipulate. However, a number of recent theoretical results suggest that this complexity may only be in the worst-case since manipulation is often easy in practice. In this paper, we show that empir...
0905.3733
Trapping Set Enumerators for Repeat Multiple Accumulate Code Ensembles
cs.IT math.IT
The serial concatenation of a repetition code with two or more accumulators has the advantage of a simple encoder structure. Furthermore, the resulting ensemble is asymptotically good and exhibits minimum distance growing linearly with block length. However, in practice these codes cannot be decoded by a maximum like...
0905.3755
Decompositions of All Different, Global Cardinality and Related Constraints
cs.AI
We show that some common and important global constraints like ALL-DIFFERENT and GCC can be decomposed into simple arithmetic constraints on which we achieve bound or range consistency, and in some cases even greater pruning. These decompositions can be easily added to new solvers. They also provide other constraints...
0905.3757
Circuit Complexity and Decompositions of Global Constraints
cs.AI cs.CC
We show that tools from circuit complexity can be used to study decompositions of global constraints. In particular, we study decompositions of global constraints into conjunctive normal form with the property that unit propagation on the decomposition enforces the same level of consistency as a specialized propagati...
0905.3763
Scenario-based Stochastic Constraint Programming
cs.AI
To model combinatorial decision problems involving uncertainty and probability, we extend the stochastic constraint programming framework proposed in [Walsh, 2002] along a number of important dimensions (e.g. to multiple chance constraints and to a range of new objectives). We also provide a new (but equivalent) sema...
0905.3766
Reasoning about soft constraints and conditional preferences: complexity results and approximation techniques
cs.AI
Many real life optimization problems contain both hard and soft constraints, as well as qualitative conditional preferences. However, there is no single formalism to specify all three kinds of information. We therefore propose a framework, based on both CP-nets and soft constraints, that handles both hard and soft co...
0905.3769
Multiset Ordering Constraints
cs.AI
We identify a new and important global (or non-binary) constraint. This constraint ensures that the values taken by two vectors of variables, when viewed as multisets, are ordered. This constraint is useful for a number of different applications including breaking symmetry and fuzzy constraint satisfaction. We propos...
0905.3771
Memory Retrieved from Single Neurons
cs.NE q-bio.NC
The paper examines the problem of accessing a vector memory from a single neuron in a Hebbian neural network. It begins with the review of the author's earlier method, which is different from the Hopfield model in that it recruits neighboring neurons by spreading activity, making it possible for single or group of ne...
0905.3830
Tag Clouds for Displaying Semantics: The Case of Filmscripts
cs.AI
We relate tag clouds to other forms of visualization, including planar or reduced dimensionality mapping, and Kohonen self-organizing maps. Using a modified tag cloud visualization, we incorporate other information into it, including text sequence and most pertinent words. Our notion of word pertinence goes beyond ju...
0905.3858
Multicasting in Large Wireless Networks: Bounds on the Minimum Energy per Bit
cs.IT math.IT
We consider scaling laws for maximal energy efficiency of communicating a message to all the nodes in a wireless network, as the number of nodes in the network becomes large. Two cases of large wireless networks are studied -- dense random networks and constant density (extended) random networks. In addition, we also...
0905.3885
Swap Bribery
cs.GT cs.AI
In voting theory, bribery is a form of manipulative behavior in which an external actor (the briber) offers to pay the voters to change their votes in order to get her preferred candidate elected. We investigate a model of bribery where the price of each vote depends on the amount of change that the voter is asked to...
0905.3934
Cooperative encoding for secrecy in interference channels
cs.IT math.IT
This paper investigates the fundamental performance limits of the two-user interference channel in the presence of an external eavesdropper. In this setting, we construct an inner bound, to the secrecy capacity region, based on the idea of cooperative encoding in which the two users cooperatively design their randomi...
0905.3964
A New Solution to the Relative Orientation Problem using only 3 Points and the Vertical Direction
cs.CV
This paper presents a new method to recover the relative pose between two images, using three points and the vertical direction information. The vertical direction can be determined in two ways: 1- using direct physical measurement like IMU (inertial measurement unit), 2- using vertical vanishing point. This knowledg...
0905.3967
Optimal byzantine resilient convergence in oblivious robot networks
cs.DC cs.RO
Given a set of robots with arbitrary initial location and no agreement on a global coordinate system, convergence requires that all robots asymptotically approach the exact same, but unknown beforehand, location. Robots are oblivious-- they do not recall the past computations -- and are allowed to move in a one-dimen...
0905.4022
Transfer Learning Using Feature Selection
cs.LG
We present three related ways of using Transfer Learning to improve feature selection. The three methods address different problems, and hence share different kinds of information between tasks or feature classes, but all three are based on the information theoretic Minimum Description Length (MDL) principle and shar...
0905.4023
DMT Optimality of LR-Aided Linear Decoders for a General Class of Channels, Lattice Designs, and System Models
cs.IT math.IT
The work identifies the first general, explicit, and non-random MIMO encoder-decoder structures that guarantee optimality with respect to the diversity-multiplexing tradeoff (DMT), without employing a computationally expensive maximum-likelihood (ML) receiver. Specifically, the work establishes the DMT optimality of ...
0905.4039
Normalized Web Distance and Word Similarity
cs.CL cs.IR
There is a great deal of work in cognitive psychology, linguistics, and computer science, about using word (or phrase) frequencies in context in text corpora to develop measures for word similarity or word association, going back to at least the 1960s. The goal of this chapter is to introduce the normalizedis a gener...
0905.4057
Coalitional Game Theory for Communication Networks: A Tutorial
cs.IT cs.GT math.IT
Game theoretical techniques have recently become prevalent in many engineering applications, notably in communications. With the emergence of cooperation as a new communication paradigm, and the need for self-organizing, decentralized, and autonomic networks, it has become imperative to seek suitable game theoretical...
0905.4087
Structural Solutions for Cross-Layer Optimization of Wireless Multimedia Transmission
cs.MM cs.IT math.IT
In this paper, we propose a systematic solution to the problem of cross-layer optimization for delay-sensitive media transmission over time-varying wireless channels as well as investigate the structures and properties of this solution, such that it can be easily implemented in various multimedia systems and applicat...
0905.4091
Hybrid ARQ in Multiple-Antenna Slow Fading Channels: Performance Limits and Optimal Linear Dispersion Code Design
cs.IT math.IT
This paper focuses on studying the fundamental performance limits and linear dispersion code design for the MIMO-ARQ slow fading channel. Optimal average rate of well-known HARQ protocols is analyzed. The optimal design of space-time coding for the MIMO-ARQ channel is discussed. Information-theoretic measures are use...
0905.4138
Faster estimation of the correlation fractal dimension using box-counting
cs.DB cs.DS
Fractal dimension is widely adopted in spatial databases and data mining, among others as a measure of dataset skewness. State-of-the-art algorithms for estimating the fractal dimension exhibit linear runtime complexity whether based on box-counting or approximation schemes. In this paper, we revisit a correlation fr...
0905.4160
Codes over Quaternion Integers with Respect to Lipschitz Metric
cs.IT math.IT
I want to withdraw this paper.
0905.4162
Google matrix, dynamical attractors and Ulam networks
cs.IR
We study the properties of the Google matrix generated by a coarse-grained Perron-Frobenius operator of the Chirikov typical map with dissipation. The finite size matrix approximant of this operator is constructed by the Ulam method. This method applied to the simple dynamical model creates the directed Ulam networks...
0905.4163
Cyclic Codes over Some Finite Rings
cs.IT math.CO math.IT
In this paper cyclic codes are established with respect to the Mannheim metric over some finite rings by using Gaussian integers and the decoding algorithm for these codes is given.
0905.4164
Iterative Decoding on Multiple Tanner Graphs Using Random Edge Local Complementation
cs.IT math.IT
In this paper, we propose to enhance the performance of the sum-product algorithm (SPA) by interleaving SPA iterations with a random local graph update rule. This rule is known as edge local complementation (ELC), and has the effect of modifying the Tanner graph while preserving the code. We have previously shown how...
0905.4165
Cyclic Codes over Some Finite Quaternion Integer Rings
cs.IT math.IT
In this paper, cyclic codes are established over some finite quaternion integer rings with respect to the quaternion Mannheim distance, and de- coding algorithm for these codes is given.
0905.4201
The Usefulness of Multilevel Hash Tables with Multiple Hash Functions in Large Databases
cs.DS cs.DB
In this work, attempt is made to select three good hash functions which uniformly distribute hash values that permute their internal states and allow the input bits to generate different output bits. These functions are used in different levels of hash tables that are coded in Java Programming Language and a quite nu...
0905.4303
On Block Noncoherent Communication with Low-Precision Phase Quantization at the Receiver
cs.IT math.IT
We consider communication over the block noncoherent AWGN channel with low-precision Analog-to-Digital Converters (ADCs) at the receiver. For standard uniform Phase Shift Keying (PSK) modulation, we investigate the performance of a receiver architecture that quantizes only the phase of the received signal; this has t...
0905.4341
Characterizing predictable classes of processes
cs.AI cs.IT math.IT math.PR
The problem is sequence prediction in the following setting. A sequence $x_1,...,x_n,...$ of discrete-valued observations is generated according to some unknown probabilistic law (measure) $\mu$. After observing each outcome, it is required to give the conditional probabilities of the next observation. The measure $\...
0905.4369
Automating Quantified Multimodal Logics in Simple Type Theory -- A Case Study
cs.AI cs.LO
In a case study we investigate whether off the shelf higher-order theorem provers and model generators can be employed to automate reasoning in and about quantified multimodal logics. In our experiments we exploit the new TPTP infrastructure for classical higher-order logic.
0905.4378
The Cramer-Rao Bound for Sparse Estimation
math.ST cs.IT math.IT stat.TH
The goal of this paper is to characterize the best achievable performance for the problem of estimating an unknown parameter having a sparse representation. Specifically, we consider the setting in which a sparsely representable deterministic parameter vector is to be estimated from measurements corrupted by Gaussian...
0905.4387
Information Modeling for a Dynamic Representation of an Emergency Situation
cs.AI cs.MA
In this paper we propose an approach to build a decision support system that can help emergency planners and responders to detect and manage emergency situations. The internal mechanism of the system is independent from the treated application. Therefore, we think the system may be used or adapted easily to different...
0905.4476
Beacon-Assisted Spectrum Access with Cooperative Cognitive Transmitter and Receiver
cs.IT math.IT
Spectrum access is an important function of cognitive radios for detecting and utilizing spectrum holes without interfering with the legacy systems. In this paper we propose novel cooperative communication models and show how deploying such cooperations between a pair of secondary transmitter and receiver assists the...
0905.4482
Topics in Compressed Sensing
math.NA cs.IT math.IT
Compressed sensing has a wide range of applications that include error correction, imaging, radar and many more. Given a sparse signal in a high dimensional space, one wishes to reconstruct that signal accurately and efficiently from a number of linear measurements much less than its actual dimension. Although in the...
0905.4541
Turbo Packet Combining Strategies for the MIMO-ISI ARQ Channel
cs.IT math.IT
This paper addresses the issue of efficient turbo packet combining techniques for coded transmission with a Chase-type automatic repeat request (ARQ) protocol operating over a multiple-input--multiple-output (MIMO) channel with intersymbol interference (ISI). First of all, we investigate the outage probability and th...
0905.4545
Minimum Distance and Convergence Analysis of Hamming-Accumulate-Acccumulate Codes
cs.IT math.IT
In this letter we consider the ensemble of codes formed by the serial concatenation of a Hamming code and two accumulate codes. We show that this ensemble is asymptotically good, in the sense that most codes in the ensemble have minimum distance growing linearly with the block length. Thus, the resulting codes achiev...
0905.4570
Weak Evolvability Equals Strong Evolvability
cs.AI cs.NE
An updated version will be uploaded later.
0905.4601
Considerations on Construction Ontologies
cs.AI
The paper proposes an analysis on some existent ontologies, in order to point out ways to resolve semantic heterogeneity in information systems. Authors are highlighting the tasks in a Knowledge Acquisiton System and identifying aspects related to the addition of new information to an intelligent system. A solution i...
0905.4605
Techniques for Securing Data Exchange between a Database Server and a Client Program
cs.DB
The goal of the presented work is to illustrate a method by which the data exchange between a standalone computer software and a shared database server can be protected of unauthorized interceptation of the traffic in Internet network, a transport network for data managed by those two systems, interceptation by which...
0905.4614
A Logic Programming Approach to Activity Recognition
cs.AI
We have been developing a system for recognising human activity given a symbolic representation of video content. The input of our system is a set of time-stamped short-term activities detected on video frames. The output of our system is a set of recognised long-term activities, which are pre-defined temporal combin...
0905.4627
CoPhIR: a Test Collection for Content-Based Image Retrieval
cs.MM cs.IR
The scalability, as well as the effectiveness, of the different Content-based Image Retrieval (CBIR) approaches proposed in literature, is today an important research issue. Given the wealth of images on the Web, CBIR systems must in fact leap towards Web-scale datasets. In this paper, we report on our experience in ...
0905.4656
Quantization Errors of fGn and fBm Signals
cs.IT math.IT
In this Letter, we show that under the assumption of high resolution, the quantization errors of fGn and fBm signals with uniform quantizer can be treated as uncorrelated white noises.
0905.4684
A Simple Sequential Spectrum Sensing Scheme for Cognitive Radio
cs.IT math.IT
Cognitive radio that supports a secondary and opportunistic access to licensed spectrum shows great potential to dramatically improve spectrum utilization. Spectrum sensing performed by secondary users to detect unoccupied spectrum bands, is a key enabling technique for cognitive radio. This paper proposes a truncate...
0905.4700
Cross-Layer Design of FDD-OFDM Systems based on ACK/NAK Feedbacks
cs.IT math.IT
It is well-known that cross-layer scheduling which adapts power, rate and user allocation can achieve significant gain on system capacity. However, conventional cross-layer designs all require channel state information at the base station (CSIT) which is difficult to obtain in practice. In this paper, we focus on cro...
0905.4713
Mining Generalized Patterns from Large Databases using Ontologies
cs.AI cs.DB cs.DM
Formal Concept Analysis (FCA) is a mathematical theory based on the formalization of the notions of concept and concept hierarchies. It has been successfully applied to several Computer Science fields such as data mining,software engineering, and knowledge engineering, and in many domains like medicine, psychology, l...
0905.4757
Stochastic Optimization for Markov Modulated Networks with Application to Delay Constrained Wireless Scheduling
math.OC cs.SY
We consider a wireless system with a small number of delay constrained users and a larger number of users without delay constraints. We develop a scheduling algorithm that reacts to time varying channels and maximizes throughput utility (to within a desired proximity), stabilizes all queues, and satisfies the delay c...
0905.4761
Optimizing XML Compression
cs.DB
The eXtensible Markup Language (XML) provides a powerful and flexible means of encoding and exchanging data. As it turns out, its main advantage as an encoding format (namely, its requirement that all open and close markup tags are present and properly balanced) yield also one of its main disadvantages: verbosity. XM...
0905.4771
Variational structure of the optimal artificial diffusion method for the advection-diffusion equation
cs.CE cs.NA
In this research note we provide a variational basis for the optimal artificial diffusion method, which has been a cornerstone in developing many stabilized methods. The optimal artificial diffusion method produces exact nodal solutions when applied to one-dimensional problems with constant coefficients and forcing f...
0905.4918
Divide and Conquer: Partitioning Online Social Networks
cs.NI cs.AI cs.DC
Online Social Networks (OSNs) have exploded in terms of scale and scope over the last few years. The unprecedented growth of these networks present challenges in terms of system design and maintenance. One way to cope with this is by partitioning such large networks and assigning these partitions to different machine...
0905.4926
On Node Density -- Outage Probability Tradeoff in Wireless Networks
cs.IT math.IT
A statistical model of interference in wireless networks is considered, which is based on the traditional propagation channel model and a Poisson model of random spatial distribution of nodes in 1-D, 2-D and 3-D spaces with both uniform and non-uniform densities. The power of nearest interferer is used as a major per...
0905.4937
A criterion for hypothesis testing for stationary processes
math.ST cs.IT math.IT math.PR stat.TH
Given a finite-valued sample $X_1,...,X_n$ we wish to test whether it was generated by a stationary ergodic process belonging to a family $H_0$, or it was generated by a stationary ergodic process outside $H_0$. We require the Type I error of the test to be uniformly bounded, while the type II error has to be mande n...
0906.0037
Asymptotic Capacity and Optimal Precoding in MIMO Multi-Hop Relay Networks
cs.IT math.IT
A multi-hop relaying system is analyzed where data sent by a multi-antenna source is relayed by successive multi-antenna relays until it reaches a multi-antenna destination. Assuming correlated fading at each hop, each relay receives a faded version of the signal from the previous level, performs linear precoding and...