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cs/0508085
On the Asymptotic Performance of Iterative Decoders for Product Codes
cs.IT cs.DM math.IT
We consider hard-decision iterative decoders for product codes over the erasure channel, which employ repeated rounds of decoding rows and columns alternatingly. We derive the exact asymptotic probability of decoding failure as a function of the error-correction capabilities of the row and column codes, the number of...
cs/0508088
Special Cases of Encodings by Generalized Adaptive Codes
cs.IT math.IT
Adaptive (variable-length) codes associate variable-length codewords to symbols being encoded depending on the previous symbols in the input data string. This class of codes has been presented in [Dragos Trinca, cs.DS/0505007] as a new class of non-standard variable-length codes. Generalized adaptive codes (GA codes,...
cs/0508092
Summarizing Reports on Evolving Events; Part I: Linear Evolution
cs.CL cs.IR
We present an approach for summarization from multiple documents which report on events that evolve through time, taking into account the different document sources. We distinguish the evolution of an event into linear and non-linear. According to our approach, each document is represented by a collection of messages...
cs/0508093
Performance of PPM Multipath Synchronization in the Limit of Large Bandwidth
cs.IT math.IT
The acquisition, or synchronization, of the multipath profile for an ultrawideband pulse position modulation (PPM) communication systems is considered. Synchronization is critical for the proper operation of PPM based For the multipath channel, it is assumed that channel gains are known, but path delays are unknown. ...
cs/0508094
Conference Key Agreement and Quantum Sharing of Classical Secrets with Noisy GHZ States
cs.IT cs.CR math.IT
We propose a wide class of distillation schemes for multi-partite entangled states that are CSS-states. Our proposal provides not only superior efficiency, but also new insights on the connection between CSS-states and bipartite graph states. We then consider the applications of our distillation schemes for two crypt...
cs/0508095
Capacity of Ultra Wide Band Wireless Ad Hoc Networks
cs.IT cs.NI math.IT
Throughput capacity is a critical parameter for the design and evaluation of ad-hoc wireless networks. Consider n identical randomly located nodes, on a unit area, forming an ad-hoc wireless network. Assuming a fixed per node transmission capability of T bits per second at a fixed range, it has been shown that the un...
cs/0508096
On Multiple User Channels with Causal State Information at the Transmitters
cs.IT math.IT
We extend Shannon's result on the capacity of channels with state information to multiple user channels. More specifically, we characterize the capacity (region) of degraded broadcast channels and physically degraded relay channels where the channel state information is causally available at the transmitters. We also...
cs/0508098
An Explicit Construction of Universally Decodable Matrices
cs.IT cs.DM math.IT
Universally decodable matrices can be used for coding purposes when transmitting over slow fading channels. These matrices are parameterized by positive integers $L$ and $n$ and a prime power $q$. Based on Pascal's triangle we give an explicit construction of universally decodable matrices for any non-zero integers $...
cs/0508099
Search Process and Probabilistic Bifix Approach
cs.IT cs.CV math.IT
An analytical approach to a search process is a mathematical prerequisite for digital synchronization acquisition analysis and optimization. A search is performed for an arbitrary set of sequences within random but not equiprobable L-ary data. This paper derives in detail an expression for probability distribution fu...
cs/0508100
A primer on Answer Set Programming
cs.AI cs.LO
A introduction to the syntax and Semantics of Answer Set Programming intended as an handout to [under]graduate students taking Artificial Intlligence or Logic Programming classes.
cs/0508101
Maximum Weight Matching via Max-Product Belief Propagation
cs.IT cs.AI math.IT
Max-product "belief propagation" is an iterative, local, message-passing algorithm for finding the maximum a posteriori (MAP) assignment of a discrete probability distribution specified by a graphical model. Despite the spectacular success of the algorithm in many application areas such as iterative decoding, compute...
cs/0508102
Investigations of Process Damping Forces in Metal Cutting
cs.CE
Using finite element software developed for metal cutting by Third Wave Systems we investigate the forces involved in chatter, a self-sustained oscillation of the cutting tool. The phenomena is decomposed into a vibrating tool cutting a flat surface work piece, and motionless tool cutting a work piece with a wavy sur...
cs/0508103
Corpus-based Learning of Analogies and Semantic Relations
cs.LG cs.CL cs.IR
We present an algorithm for learning from unlabeled text, based on the Vector Space Model (VSM) of information retrieval, that can solve verbal analogy questions of the kind found in the SAT college entrance exam. A verbal analogy has the form A:B::C:D, meaning "A is to B as C is to D"; for example, mason:stone::carp...
cs/0508104
A Generalised Hadamard Transform
cs.IT cs.DM math.IT
A Generalised Hadamard Transform for multi-phase or multilevel signals is introduced, which includes the Fourier, Generalised, Discrete Fourier, Walsh-Hadamard and Reverse Jacket Transforms. The jacket construction is formalised and shown to admit a tensor product decomposition. Primary matrices under this decomposit...
cs/0508107
New Upper Bounds on A(n,d)
cs.IT cs.DM math.IT
Upper bounds on the maximum number of codewords in a binary code of a given length and minimum Hamming distance are considered. New bounds are derived by a combination of linear programming and counting arguments. Some of these bounds improve on the best known analytic bounds. Several new record bounds are obtained f...
cs/0508114
A Family of Binary Sequences with Optimal Correlation Property and Large Linear Span
cs.CR cs.IT math.IT
A family of binary sequences is presented and proved to have optimal correlation property and large linear span. It includes the small set of Kasami sequences, No sequence set and TN sequence set as special cases. An explicit lower bound expression on the linear span of sequences in the family is given. With suitable...
cs/0508115
New Sequence Sets with Zero-Correlation Zone
cs.IT math.IT
A method for constructing sets of sequences with zero-correlation zone (ZCZ sequences) and sequence sets with low cross correlation is proposed. The method is to use families of short sequences and complete orthogonal sequence sets to derive families of long sequences with desired correlation properties. It is a unif...
cs/0508117
Long-term neuronal behavior caused by two synaptic modification mechanisms
cs.NE cs.CE
We report the first results of simulating the coupling of neuronal, astrocyte, and cerebrovascular activity. It is suggested that the dynamics of the system is different from systems that only include neurons. In the neuron-vascular coupling, distribution of synapse strengths affects neuronal behavior and thus balanc...
cs/0508118
Unified Theory of Source Coding: Part I -- Two Terminal Problems
cs.IT math.IT
Since the publication of Shannon's theory of one terminal source coding, a number of interesting extensions have been derived by researchers such as Slepian-Wolf, Wyner, Ahlswede-K\"{o}rner, Wyner-Ziv and Berger-Yeung. Specifically, the achievable rate or rate-distortion region has been described by a first order inf...
cs/0508119
Unified Theory of Source Coding: Part II -- Multiterminal Problems
cs.IT math.IT
In the first paper of this two part communication, we solved in a unified framework a variety of two terminal source coding problems with noncooperative encoders, thereby consolidating works of Shannon, Slepian-Wolf, Wyner, Ahlswede-K\"{o}rner, Wyner-Ziv, Berger {\em et al.} and Berger-Yeung. To achieve such unificat...
cs/0508120
Iterative Algorithm for Finding Frequent Patterns in Transactional Databases
cs.DB
A high-performance algorithm for searching for frequent patterns (FPs) in transactional databases is presented. The search for FPs is carried out by using an iterative sieve algorithm by computing the set of enclosed cycles. In each inner cycle of level FPs composed of elements are generated. The assigned number of e...
cs/0508121
How Good is Phase-Shift Keying for Peak-Limited Rayleigh Fading Channels in the Low-SNR Regime?
cs.IT math.IT
This paper investigates the achievable information rate of phase-shift keying (PSK) over frequency non-selective Rayleigh fading channels without channel state information (CSI). The fading process exhibits general temporal correlation characterized by its spectral density function. We consider both discrete-time and...
cs/0508122
Streaming and Sublinear Approximation of Entropy and Information Distances
cs.DS cs.IT math.IT
In many problems in data mining and machine learning, data items that need to be clustered or classified are not points in a high-dimensional space, but are distributions (points on a high dimensional simplex). For distributions, natural measures of distance are not the $\ell_p$ norms and variants, but information-th...
cs/0508124
Coding Schemes for Line Networks
cs.IT cs.DC cs.NI math.IT
We consider a simple network, where a source and destination node are connected with a line of erasure channels. It is well known that in order to achieve the min-cut capacity, the intermediate nodes are required to process the information. We propose coding schemes for this setting, and discuss each scheme in terms ...
cs/0508126
A Closed-Form Solution for the Finite Length Constant Modulus Receiver
cs.GT cs.IT math.IT
In this paper, a closed-form solution minimizing the Godard or Constant Modulus (CM) cost function under the practical conditions of finite SNR and finite equalizer length is derived. While previous work has been reported by Zeng et al., IEEE Trans. Information Theory. 1998, to establish the link between the constant...
cs/0508127
On context-tree prediction of individual sequences
cs.IT math.IT
Motivated by the evident success of context-tree based methods in lossless data compression, we explore, in this paper, methods of the same spirit in universal prediction of individual sequences. By context-tree prediction, we refer to a family of prediction schemes, where at each time instant $t$, after having obser...
cs/0508129
Temporal Phylogenetic Networks and Logic Programming
cs.LO cs.AI cs.PL
The concept of a temporal phylogenetic network is a mathematical model of evolution of a family of natural languages. It takes into account the fact that languages can trade their characteristics with each other when linguistic communities are in contact, and also that a contact is only possible when the languages ar...
cs/0508130
A Fresh Look at the Reliability of Long-term Digital Storage
cs.DL cs.DB cs.OS
Many emerging Web services, such as email, photo sharing, and web site archives, need to preserve large amounts of quickly-accessible data indefinitely into the future. In this paper, we make the case that these applications' demands on large scale storage systems over long time horizons require us to re-evaluate tra...
cs/0508132
Planning with Preferences using Logic Programming
cs.AI
We present a declarative language, PP, for the high-level specification of preferences between possible solutions (or trajectories) of a planning problem. This novel language allows users to elegantly express non-trivial, multi-dimensional preferences and priorities over such preferences. The semantics of PP allows t...
cs/0509001
Asymptotic Behavior of Error Exponents in the Wideband Regime
cs.IT math.IT
In this paper, we complement Verd\'{u}'s work on spectral efficiency in the wideband regime by investigating the fundamental tradeoff between rate and bandwidth when a constraint is imposed on the error exponent. Specifically, we consider both AWGN and Rayleigh-fading channels. For the AWGN channel model, the optimal...
cs/0509002
Component Based Programming in Scientific Computing: The Viable Approach
cs.CE
Computational scientists are facing a new era where the old ways of developing and reusing code have to be left behind and a few daring steps are to be made towards new horizons. The present work analyzes the needs that drive this change, the factors that contribute to the inertia of the community and slow the transi...
cs/0509003
COMODI: Architecture for a Component-Based Scientific Computing System
cs.CE
The COmputational MODule Integrator (COMODI) is an initiative aiming at a component based framework, component developer tool and component repository for scientific computing. We identify the main ingredients to a solution that would be sufficiently appealing to scientists and engineers to consider alternatives to t...
cs/0509005
Combining Structured Corporate Data and Document Content to Improve Expertise Finding
cs.IR
In this paper, we present an algorithm for automatically building expertise evidence for finding experts within an organization by combining structured corporate information with different content. We also describe our test data collection and our evaluation method. Evaluation of the algorithm shows that using organi...
cs/0509006
Optimal space-time codes for the MIMO amplify-and-forward cooperative channel
cs.IT math.IT
In this work, we extend the non-orthogonal amplify-and-forward (NAF) cooperative diversity scheme to the MIMO channel. A family of space-time block codes for a half-duplex MIMO NAF fading cooperative channel with N relays is constructed. The code construction is based on the non-vanishing determinant criterion (NVD) ...
cs/0509007
Non-Data-Aided Parameter Estimation in an Additive White Gaussian Noise Channel
cs.IT math.IT
Non-data-aided (NDA) parameter estimation is considered for binary-phase-shift-keying transmission in an additive white Gaussian noise channel. Cramer-Rao lower bounds (CRLBs) for signal amplitude, noise variance, channel reliability constant and bit-error rate are derived and it is shown how these parameters relate ...
cs/0509008
Joint Equalization and Decoding for Nonlinear Two-Dimensional Intersymbol Interference Channels with Application to Optical Storage
cs.IT math.IT
An algorithm that performs joint equalization and decoding for nonlinear two-dimensional intersymbol interference channels is presented. The algorithm performs sum-product message-passing on a factor graph that represents the underlying system. The two-dimensional optical storage (TWODOS) technology is an example of ...
cs/0509009
Joint Equalization and Decoding for Nonlinear Two-Dimensional Intersymbol Interference Channels
cs.IT math.IT
An algorithm that performs joint equalization and decoding for channels with nonlinear two-dimensional intersymbol interference is presented. The algorithm performs sum-product message-passing on a factor graph that represents the underlying system. The two-dimensional optical storage (TwoDOS) technology is an exampl...
cs/0509010
Minimum Mean-Square-Error Equalization using Priors for Two-Dimensional Intersymbol Interference
cs.IT math.IT
Joint equalization and decoding schemes are described for two-dimensional intersymbol interference (ISI) channels. Equalization is performed using the minimum mean-square-error (MMSE) criterion. Low-density parity-check codes are used for error correction. The MMSE schemes are the extension of those proposed by Tuech...
cs/0509011
Clustering Mixed Numeric and Categorical Data: A Cluster Ensemble Approach
cs.AI
Clustering is a widely used technique in data mining applications for discovering patterns in underlying data. Most traditional clustering algorithms are limited to handling datasets that contain either numeric or categorical attributes. However, datasets with mixed types of attributes are common in real life data mi...
cs/0509012
Kriging Scenario For Capital Markets
cs.CE
An introduction to numerical statistics.
cs/0509013
On the variational distance of independently repeated experiments
cs.IT math.IT
Let P and Q be two probability distributions which differ only for values with non-zero probability. We show that the variational distance between the n-fold product distributions P^n and Q^n cannot grow faster than the square root of n.
cs/0509014
Density Evolution for Asymmetric Memoryless Channels
cs.IT math.IT
Density evolution is one of the most powerful analytical tools for low-density parity-check (LDPC) codes and graph codes with message passing decoding algorithms. With channel symmetry as one of its fundamental assumptions, density evolution (DE) has been widely and successfully applied to different channels, includi...
cs/0509015
Optimal Prefix Codes with Fewer Distinct Codeword Lengths are Faster to Construct
cs.DS cs.IT math.IT
A new method for constructing minimum-redundancy binary prefix codes is described. Our method does not explicitly build a Huffman tree; instead it uses a property of optimal prefix codes to compute the codeword lengths corresponding to the input weights. Let $n$ be the number of weights and $k$ be the number of disti...
cs/0509017
Traders imprint themselves by adaptively updating their own avatar
cs.MA cs.CE
Simulations of artificial stock markets were considered as early as 1964 and multi-agent ones were introduced as early as 1989. Starting the early 90's, collaborations of economists and physicists produced increasingly realistic simulation platforms. Currently, the market stylized facts are easily reproduced and one ...
cs/0509020
Transitive Text Mining for Information Extraction and Hypothesis Generation
cs.IR cs.AI
Transitive text mining - also named Swanson Linking (SL) after its primary and principal researcher - tries to establish meaningful links between literature sets which are virtually disjoint in the sense that each does not mention the main concept of the other. If successful, SL may give rise to the development of ne...
cs/0509021
The Throughput-Reliability Tradeoff in MIMO Channels
cs.IT math.IT
In this paper, an outage limited MIMO channel is considered. We build on Zheng and Tse's elegant formulation of the diversity-multiplexing tradeoff to develop a better understanding of the asymptotic relationship between the probability of error, transmission rate, and signal-to-noise ratio. In particular, we identif...
cs/0509022
Achievable Rates for Pattern Recognition
cs.IT cs.CV math.IT
Biological and machine pattern recognition systems face a common challenge: Given sensory data about an unknown object, classify the object by comparing the sensory data with a library of internal representations stored in memory. In many cases of interest, the number of patterns to be discriminated and the richness ...
cs/0509025
A formally verified proof of the prime number theorem
cs.AI cs.LO cs.SC
The prime number theorem, established by Hadamard and de la Vall'ee Poussin independently in 1896, asserts that the density of primes in the positive integers is asymptotic to 1 / ln x. Whereas their proofs made serious use of the methods of complex analysis, elementary proofs were provided by Selberg and Erd"os in 1...
cs/0509028
Projecting the Forward Rate Flow onto a Finite Dimensional Manifold
cs.CE cs.IT math.IT
Given a Heath-Jarrow-Morton (HJM) interest rate model $\mathcal{M}$ and a parametrized family of finite dimensional forward rate curves $\mathcal{G}$, this paper provides a technique for projecting the infinite dimensional forward rate curve $r_{t}$ given by $\mathcal{M}$ onto the finite dimensional manifold $\mathca...
cs/0509029
Quickest detection of a minimum of disorder times
cs.CE cs.IT math.IT
A multi-source quickest detection problem is considered. Assume there are two independent Poisson processes $X^{1}$ and $X^{2}$ with disorder times $\theta_{1}$ and $\theta_{2}$, respectively; that is, the intensities of $X^1$ and $X^2$ change at random unobservable times $\theta_1$ and $\theta_2$, respectively. $\th...
cs/0509032
A Simple Model to Generate Hard Satisfiable Instances
cs.AI cond-mat.stat-mech cs.CC
In this paper, we try to further demonstrate that the models of random CSP instances proposed by [Xu and Li, 2000; 2003] are of theoretical and practical interest. Indeed, these models, called RB and RD, present several nice features. First, it is quite easy to generate random instances of any arity since no particul...
cs/0509033
K-Histograms: An Efficient Clustering Algorithm for Categorical Dataset
cs.AI
Clustering categorical data is an integral part of data mining and has attracted much attention recently. In this paper, we present k-histogram, a new efficient algorithm for clustering categorical data. The k-histogram algorithm extends the k-means algorithm to categorical domain by replacing the means of clusters w...
cs/0509037
Friends for Free: Self-Organizing Artificial Social Networks for Trust and Cooperation
cs.MA
By harvesting friendship networks from e-mail contacts or instant message "buddy lists" Peer-to-Peer (P2P) applications can improve performance in low trust environments such as the Internet. However, natural social networks are not always suitable, reliable or available. We propose an algorithm (SLACER) that allows ...
cs/0509039
Coding for the feedback Gel'fand-Pinsker channel and the feedforward Wyner-Ziv source
cs.IT math.IT
We consider both channel coding and source coding, with perfect past feedback/feedforward, in the presence of side information. It is first observed that feedback does not increase the capacity of the Gel'fand-Pinsker channel, nor does feedforward improve the achievable rate-distortion performance in the Wyner-Ziv pr...
cs/0509040
Authoring case based training by document data extraction
cs.AI cs.IR
In this paper, we propose an scalable approach to modeling based upon word processing documents, and we describe the tool Phoenix providing the technical infrastructure. For our training environment d3web.Train, we developed a tool to extract case knowledge from existing documents, usually dismissal records, extend...
cs/0509041
Efficient Reconciliation of Correlated Continuous Random Variables using LDPC Codes
cs.IT math.IT
This paper investigates an efficient and practical information reconciliation method in the case where two parties have access to correlated continuous random variables. We show that reconciliation is a special case of channel coding and that existing coded modulation techniques can be adapted for reconciliation. We ...
cs/0509043
Optimal Power Control for Multiuser CDMA Channels
cs.IT math.IT
In this paper, we define the power region as the set of power allocations for K users such that everybody meets a minimum signal-to-interference ratio (SIR). The SIR is modeled in a multiuser CDMA system with fixed linear receiver and signature sequences. We show that the power region is convex in linear and logarith...
cs/0509044
Accumulate-Repeat-Accumulate Codes: Systematic Codes Achieving the Binary Erasure Channel Capacity with Bounded Complexity
cs.IT math.IT
The paper introduces ensembles of accumulate-repeat-accumulate (ARA) codes which asymptotically achieve capacity on the binary erasure channel (BEC) with {\em bounded complexity} per information bit. It also introduces symmetry properties which play a central role in the construction of capacity-achieving ensembles f...
cs/0509045
On Hats and other Covers
cs.IT math.IT
We study a game puzzle that has enjoyed recent popularity among mathematicians, computer scientist, coding theorists and even the mass press. In the game, $n$ players are fitted with randomly assigned colored hats. Individual players can see their teammates' hat colors, but not their own. Based on this information, a...
cs/0509046
On the number of t-ary trees with a given path length
cs.DM cs.IT math.IT
We show that the number of $t$-ary trees with path length equal to $p$ is $\exp(h(t^{-1})t\log t \frac{p}{\log p}(1+o(1)))$, where $\entropy(x){=}{-}x\log x {-}(1{-}x)\log (1{-}x)$ is the binary entropy function. Besides its intrinsic combinatorial interest, the question recently arose in the context of information t...
cs/0509047
Secure multiplex coding to attain the channel capacity in wiretap channels
cs.IT cs.CR math.IT
It is known that a message can be transmitted safely against any wiretapper via a noisy channel without a secret key if the coding rate is less than the so-called secrecy capacity $C_S$, which is usually smaller than the channel capacity $C$. In order to remove the loss $C - C_S$, we propose a multiplex coding scheme...
cs/0509048
Capacity of Complexity-Constrained Noise-Free CDMA
cs.IT math.IT
An interference-limited noise-free CDMA downlink channel operating under a complexity constraint on the receiver is introduced. According to this paradigm, detected bits, obtained by performing hard decisions directly on the channel's matched filter output, must be the same as the transmitted binary inputs. This chan...
cs/0509049
On the Achievable Information Rates of CDMA Downlink with Trivial Receivers
cs.IT math.IT
A noisy CDMA downlink channel operating under a strict complexity constraint on the receiver is introduced. According to this constraint, detected bits, obtained by performing hard decisions directly on the channel's matched filter output, must be the same as the transmitted binary inputs. This channel setting, allow...
cs/0509050
Effect of door delay on aircraft evacuation time
cs.MA
The recent commercial launch of twin-deck Very Large Transport Aircraft (VLTA) such as the Airbus A380 has raised questions concerning the speed at which they may be evacuated. The abnormal height of emergency exits on the upper deck has led to speculation that emotional factors such as fear may lead to door delay, a...
cs/0509053
Underwater Hacker Missile Wars: A Cryptography and Engineering Contest
cs.CR cs.CE
For a recent student conference, the authors developed a day-long design problem and competition suitable for engineering, mathematics and science undergraduates. The competition included a cryptography problem, for which a workshop was run during the conference. This paper describes the competition, focusing on the ...
cs/0509055
Learning Optimal Augmented Bayes Networks
cs.LG
Naive Bayes is a simple Bayesian classifier with strong independence assumptions among the attributes. This classifier, desipte its strong independence assumptions, often performs well in practice. It is believed that relaxing the independence assumptions of a naive Bayes classifier may improve the classification acc...
cs/0509058
Interactive Unawareness Revisited
cs.AI cs.LO
We analyze a model of interactive unawareness introduced by Heifetz, Meier and Schipper (HMS). We consider two axiomatizations for their model, which capture different notions of validity. These axiomatizations allow us to compare the HMS approach to both the standard (S5) epistemic logic and two other approaches to ...
cs/0509061
Guarantees for the Success Frequency of an Algorithm for Finding Dodgson-Election Winners
cs.DS cs.MA
In the year 1876 the mathematician Charles Dodgson, who wrote fiction under the now more famous name of Lewis Carroll, devised a beautiful voting system that has long fascinated political scientists. However, determining the winner of a Dodgson election is known to be complete for the \Theta_2^p level of the polynomi...
cs/0509062
Capacity-Achieving Codes with Bounded Graphical Complexity on Noisy Channels
cs.IT math.IT
We introduce a new family of concatenated codes with an outer low-density parity-check (LDPC) code and an inner low-density generator matrix (LDGM) code, and prove that these codes can achieve capacity under any memoryless binary-input output-symmetric (MBIOS) channel using maximum-likelihood (ML) decoding with bound...
cs/0509064
On joint coding for watermarking and encryption
cs.IT cs.CR math.IT
In continuation to earlier works where the problem of joint information embedding and lossless compression (of the composite signal) was studied in the absence \cite{MM03} and in the presence \cite{MM04} of attacks, here we consider the additional ingredient of protecting the secrecy of the watermark against an unaut...
cs/0509065
On Deciding Deep Holes of Reed-Solomon Codes
cs.IT math.IT
For generalized Reed-Solomon codes, it has been proved \cite{GuruswamiVa05} that the problem of determining if a received word is a deep hole is co-NP-complete. The reduction relies on the fact that the evaluation set of the code can be exponential in the length of the code -- a property that practical codes do not u...
cs/0509068
Channel Uncertainty in Ultra Wideband Communication Systems
cs.IT math.IT
Wide band systems operating over multipath channels may spread their power over bandwidth if they use duty cycle. Channel uncertainty limits the achievable data rates of power constrained wide band systems; Duty cycle transmission reduces the channel uncertainty because the receiver has to estimate the channel only w...
cs/0509071
CP-nets and Nash equilibria
cs.GT cs.AI
We relate here two formalisms that are used for different purposes in reasoning about multi-agent systems. One of them are strategic games that are used to capture the idea that agents interact with each other while pursuing their own interest. The other are CP-nets that were introduced to express qualitative and con...
cs/0509072
Folksonomy as a Complex Network
cs.IR cs.DL physics.soc-ph
Folksonomy is an emerging technology that works to classify the information over WWW through tagging the bookmarks, photos or other web-based contents. It is understood to be organized by every user while not limited to the authors of the contents and the professional editors. This study surveyed the folksonomy as a ...
cs/0509073
Distance-Increasing Maps of All Length by Simple Mapping Algorithms
cs.IT cs.DM math.IT
Distance-increasing maps from binary vectors to permutations, namely DIMs, are useful for the construction of permutation arrays. While a simple mapping algorithm defining DIMs of even length is known, existing DIMs of odd length are either recursively constructed by merging shorter DIMs or defined by much complicate...
cs/0509075
On the Capacity of Doubly Correlated MIMO Channels
cs.IT math.IT
In this paper, we analyze the capacity of multiple-input multiple-output (MIMO) Rayleigh-fading channels in the presence of spatial fading correlation at both the transmitter and the receiver, assuming that the channel is unknown at the transmitter and perfectly known at the receiver. We first derive the determinant ...
cs/0509077
Capacity Limits of Cognitive Radio with Distributed and Dynamic Spectral Activity
cs.IT math.IT
We investigate the capacity of opportunistic communication in the presence of dynamic and distributed spectral activity, i.e. when the time varying spectral holes sensed by the cognitive transmitter are correlated but not identical to those sensed by the cognitive receiver. Using the information theoretic framework o...
cs/0509078
On the Feedback Capacity of Stationary Gaussian Channels
cs.IT math.IT
The capacity of stationary additive Gaussian noise channels with feedback is characterized as the solution to a variational problem. Toward this end, it is proved that the optimal feedback coding scheme is stationary. When specialized to the first-order autoregressive moving-average noise spectrum, this variational c...
cs/0509079
The WSSUS Pulse Design Problem in Multicarrier Transmission
cs.IT math.IT
Optimal link adaption to the scattering function of wide sense stationary uncorrelated mobile communication channels is still an unsolved problem despite its importance for next-generation system design. In multicarrier transmission such link adaption is performed by pulse shaping, i.e. by properly adjusting the tran...
cs/0509080
Capacity and Character Expansions: Moment generating function and other exact results for MIMO correlated channels
cs.IT cond-mat.mes-hall cond-mat.stat-mech hep-lat math-ph math.IT math.MP
We apply a promising new method from the field of representations of Lie groups to calculate integrals over unitary groups, which are important for multi-antenna communications. To demonstrate the power and simplicity of this technique, we first re-derive a number of results that have been used recently in the commun...
cs/0509081
Automatic Face Recognition System Based on Local Fourier-Bessel Features
cs.CV
We present an automatic face verification system inspired by known properties of biological systems. In the proposed algorithm the whole image is converted from the spatial to polar frequency domain by a Fourier-Bessel Transform (FBT). Using the whole image is compared to the case where only face image regions (local...
cs/0509082
Face Recognition Based on Polar Frequency Features
cs.CV
A novel biologically motivated face recognition algorithm based on polar frequency is presented. Polar frequency descriptors are extracted from face images by Fourier-Bessel transform (FBT). Next, the Euclidean distance between all images is computed and each image is now represented by its dissimilarity to the other...
cs/0509083
Face Verification in Polar Frequency Domain: a Biologically Motivated Approach
cs.CV
We present a novel local-based face verification system whose components are analogous to those of biological systems. In the proposed system, after global registration and normalization, three eye regions are converted from the spatial to polar frequency domain by a Fourier-Bessel Transform. The resulting representa...
cs/0509085
An Improved Lower Bound to the Number of Neighbors Required for the Asymptotic Connectivity of Ad Hoc Networks
cs.NI cs.IT math.IT
Xue and Kumar have established that the number of neighbors required for connectivity of wireless networks with N uniformly distributed nodes must grow as log(N), and they also established that the actual number required lies between 0.074log(N) and 5.1774log(N). In this short paper, by recognizing that connectivity ...
cs/0509086
Statistical Mechanical Approach to Lossy Data Compression:Theory and Practice
cs.IT math.IT
The encoder and decoder for lossy data compression of binary memoryless sources are developed on the basis of a specific-type nonmonotonic perceptron. Statistical mechanical analysis indicates that the potential ability of the perceptron-based code saturates the theoretically achievable limit in most cases although e...
cs/0509087
On Time-Variant Distortions in Multicarrier Transmission with Application to Frequency Offsets and Phase Noise
cs.IT math.IT
Phase noise and frequency offsets are due to their time-variant behavior one of the most limiting disturbances in practical OFDM designs and therefore intensively studied by many authors. In this paper we present a generalized framework for the prediction of uncoded system performance in the presence of time-variant ...
cs/0509088
Business intelligence systems and user's parameters: an application to a documents' database
cs.DB
This article presents earlier results of our research works in the area of modeling Business Intelligence Systems. The basic idea of this research area is presented first. We then show the necessity of including certain users' parameters in Information systems that are used in Business Intelligence systems in order t...
cs/0509089
Semantics of UML 2.0 Activity Diagram for Business Modeling by Means of Virtual Machine
cs.CE cs.PL
The paper proposes a more formalized definition of UML 2.0 Activity Diagram semantics. A subset of activity diagram constructs relevant for business process modeling is considered. The semantics definition is based on the original token flow methodology, but a more constructive approach is used. The Activity Diagram ...
cs/0509092
Automatic extraction of paraphrastic phrases from medium size corpora
cs.CL cs.AI
This paper presents a versatile system intended to acquire paraphrastic phrases from a representative corpus. In order to decrease the time spent on the elaboration of resources for NLP system (for example Information Extraction, IE hereafter), we suggest to use a machine learning system that helps defining new templ...
cs/0509093
On the Outage Capacity of Correlated Multiple-Path MIMO Channels
cs.IT math.IT
The use of multi-antenna arrays in both transmission and reception has been shown to dramatically increase the throughput of wireless communication systems. As a result there has been considerable interest in characterizing the ergodic average of the mutual information for realistic correlated channels. Here, an appr...
cs/0509096
Performance Analysis and Enhancement of Multiband OFDM for UWB Communications
cs.IT math.IT
In this paper, we analyze the frequency-hopping orthogonal frequency-division multiplexing (OFDM) system known as Multiband OFDM for high-rate wireless personal area networks (WPANs) based on ultra-wideband (UWB) transmission. Besides considering the standard, we also propose and study system performance enhancements...
cs/0509097
Iterative Algebraic Soft-Decision List Decoding of Reed-Solomon Codes
cs.IT math.IT
In this paper, we present an iterative soft-decision decoding algorithm for Reed-Solomon codes offering both complexity and performance advantages over previously known decoding algorithms. Our algorithm is a list decoding algorithm which combines two powerful soft decision decoding techniques which were previously r...
cs/0509098
Applications of correlation inequalities to low density graphical codes
cs.IT cond-mat.stat-mech math.IT
This contribution is based on the contents of a talk delivered at the Next-SigmaPhi conference held in Crete in August 2005. It is adressed to an audience of physicists with diverse horizons and does not assume any background in communications theory. Capacity approaching error correcting codes for channel communicat...
cs/0510001
Retinal Vessel Segmentation Using the 2-D Morlet Wavelet and Supervised Classification
cs.CV
We present a method for automated segmentation of the vasculature in retinal images. The method produces segmentations by classifying each image pixel as vessel or non-vessel, based on the pixel's feature vector. Feature vectors are composed of the pixel's intensity and continuous two-dimensional Morlet wavelet trans...
cs/0510002
Optimal Relay Functionality for SNR Maximization in Memoryless Relay Networks
cs.IT math.IT
We explore the SNR-optimal relay functionality in a \emph{memoryless} relay network, i.e. a network where, during each channel use, the signal transmitted by a relay depends only on the last received symbol at that relay. We develop a generalized notion of SNR for the class of memoryless relay functions. The solution...
cs/0510003
Generalized ABBA Space-Time Block Codes
cs.IT math.IT
Linear space-time block codes (STBCs) of unitary rate and full diversity, systematically constructed over arbitrary constellations for any number of transmit antennas are introduced. The codes are obtained by generalizing the existing ABBA STBCs, a.k.a quasi-orthogonal STBCs (QO-STBCs). Furthermore, a fully orthogona...
cs/0510005
Taylor series expansions for the entropy rate of Hidden Markov Processes
cs.IT cond-mat.stat-mech math.IT
Finding the entropy rate of Hidden Markov Processes is an active research topic, of both theoretical and practical importance. A recently used approach is studying the asymptotic behavior of the entropy rate in various regimes. In this paper we generalize and prove a previous conjecture relating the entropy rate to e...
cs/0510008
Accurate and robust image superresolution by neural processing of local image representations
cs.CV cs.NE
Image superresolution involves the processing of an image sequence to generate a still image with higher resolution. Classical approaches, such as bayesian MAP methods, require iterative minimization procedures, with high computational costs. Recently, the authors proposed a method to tackle this problem, based on th...
cs/0510009
Tree-Based Construction of LDPC Codes Having Good Pseudocodeword Weights
cs.IT math.IT
We present a tree-based construction of LDPC codes that have minimum pseudocodeword weight equal to or almost equal to the minimum distance, and perform well with iterative decoding. The construction involves enumerating a $d$-regular tree for a fixed number of layers and employing a connection algorithm based on per...
cs/0510013
Safe Data Sharing and Data Dissemination on Smart Devices
cs.CR cs.DB
The erosion of trust put in traditional database servers, the growing interest for different forms of data dissemination and the concern for protecting children from suspicious Internet content are different factors that lead to move the access control from servers to clients. Several encryption schemes can be used t...