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0707.4032
One-way Hash Function Based on Neural Network
cs.CR cs.NE
A hash function is constructed based on a three-layer neural network. The three neuron-layers are used to realize data confusion, diffusion and compression respectively, and the multi-block hash mode is presented to support the plaintext with variable length. Theoretical analysis and experimental results show that th...
0707.4081
Geometrical derivation of the Boltzmann factor
nlin.CD cond-mat.stat-mech cs.MA physics.soc-ph
We show that the Boltzmann factor has a geometrical origin. Its derivation follows from the microcanonical picture. The Maxwell-Boltzmann distribution or the wealth distribution in human society are some direct applications of this new interpretation.
0707.4083
Chain of Separable Binary Goppa Codes and their Minimal Distance
cs.IT math.IT
It is shown that subclasses of separable binary Goppa codes, $\Gamma(L,G)$ - codes, with $L=\{\alpha \in GF(2^{2l}):G(\alpha)\neq 0 \}$ and special Goppa polynomials G(x) can be presented as a chain of embedded codes. The true minimal distance has been obtained for all codes of the chain.
0707.4133
Multiuser Successive Refinement and Multiple Description Coding
cs.IT math.IT
We consider the multiuser successive refinement (MSR) problem, where the users are connected to a central server via links with different noiseless capacities, and each user wishes to reconstruct in a successive-refinement fashion. An achievable region is given for the two-user two-layer case and it provides the comp...
0707.4289
A Leaf Recognition Algorithm for Plant Classification Using Probabilistic Neural Network
cs.AI
In this paper, we employ Probabilistic Neural Network (PNN) with image and data processing techniques to implement a general purpose automated leaf recognition algorithm. 12 leaf features are extracted and orthogonalized into 5 principal variables which consist the input vector of the PNN. The PNN is trained by 1800 ...
0707.4304
Spatial Aggregation: Data Model and Implementation
cs.DB
Data aggregation in Geographic Information Systems (GIS) is only marginally present in commercial systems nowadays, mostly through ad-hoc solutions. In this paper, we first present a formal model for representing spatial data. This model integrates geographic data and information contained in data warehouses external...
0707.4311
Embedded Rank Distance Codes for ISI channels
cs.IT math.IT
Designs for transmit alphabet constrained space-time codes naturally lead to questions about the design of rank distance codes. Recently, diversity embedded multi-level space-time codes for flat fading channels have been designed from sets of binary matrices with rank distance guarantees over the binary field by mapp...
0707.4360
Linear-programming Decoding of Non-binary Linear Codes
cs.IT math.IT
We develop a framework for linear-programming (LP) decoding of non-binary linear codes over rings. We prove that the resulting LP decoder has the `maximum likelihood certificate' property, and we show that the decoder output is the lowest cost pseudocodeword. Equivalence between pseudocodewords of the linear program ...
0707.4507
Competitive minimax universal decoding for several ensembles of random codes
cs.IT math.IT
Universally achievable error exponents pertaining to certain families of channels (most notably, discrete memoryless channels (DMC's)), and various ensembles of random codes, are studied by combining the competitive minimax approach, proposed by Feder and Merhav, with Chernoff bound and Gallager's techniques for the ...
0707.4518
On Throughput Scaling of Wireless Networks: Effect of Node Density and Propagation Model
cs.IT math.IT
This paper derives a lower bound to the per-node throughput achievable by a wireless network when n source-destination pairs are randomly distributed throughout a disk of radius $n^\gamma$, $ \gamma \geq 0$, propagation is modeled by attenuation of the form $1/(1+d)^\alpha$, $\alpha >2$, and successful transmission o...
0707.4524
Image Authentication Based on Neural Networks
cs.MM cs.NE
Neural network has been attracting more and more researchers since the past decades. The properties, such as parameter sensitivity, random similarity, learning ability, etc., make it suitable for information protection, such as data encryption, data authentication, intrusion detection, etc. In this paper, by investig...
0707.4597
Side-information Scalable Source Coding
cs.IT math.IT
The problem of side-information scalable (SI-scalable) source coding is considered in this work, where the encoder constructs a progressive description, such that the receiver with high quality side information will be able to truncate the bitstream and reconstruct in the rate distortion sense, while the receiver wit...
0707.4656
Communication under Strong Asynchronism
cs.IT math.IT
We consider asynchronous communication over point-to-point discrete memoryless channels. The transmitter starts sending one block codeword at an instant that is uniformly distributed within a certain time period, which represents the level of asynchronism. The receiver, by means of a sequential decoder, must isolate ...
0708.0053
Periodic complementary sets of binary sequences
cs.IT math.CO math.IT
Let PCS_p^N denote a set of p binary sequences of length N such that the sum of their periodic auto-correlation functions is a delta-function. In the 1990, Boemer and Antweiler addressed the problem of constructing such sequences. They presented a table covering the range p <= 12, N <= 50 and showing in which cases i...
0708.0171
Virtual screening with support vector machines and structure kernels
q-bio.QM cs.LG
Support vector machines and kernel methods have recently gained considerable attention in chemoinformatics. They offer generally good performance for problems of supervised classification or regression, and provide a flexible and computationally efficient framework to include relevant information and prior knowledge ...
0708.0224
Multisource Bayesian sequential change detection
math.ST cs.IT math.IT math.PR stat.TH
Suppose that local characteristics of several independent compound Poisson and Wiener processes change suddenly and simultaneously at some unobservable disorder time. The problem is to detect the disorder time as quickly as possible after it happens and minimize the rate of false alarms at the same time. These proble...
0708.0242
Distributing the Kalman Filter for Large-Scale Systems
cs.IT math.IT
This paper derives a \emph{distributed} Kalman filter to estimate a sparsely connected, large-scale, $n-$dimensional, dynamical system monitored by a network of $N$ sensors. Local Kalman filters are implemented on the ($n_l-$dimensional, where $n_l\ll n$) sub-systems that are obtained after spatially decomposing the ...
0708.0271
Capacity Region of the Finite-State Multiple Access Channel with and without Feedback
cs.IT math.IT
The capacity region of the Finite-State Multiple Access Channel (FS-MAC) with feedback that may be an arbitrary time-invariant function of the channel output samples is considered. We characterize both an inner and an outer bound for this region, using Masseys's directed information. These bounds are shown to coincid...
0708.0353
The Local Fractal Properties of the Financial Time Series on the Polish Stock Exchange Market
q-fin.ST cs.CE physics.data-an
We investigate the local fractal properties of the financial time series based on the evolution of the Warsaw Stock Exchange Index (WIG) connected with the largest developing financial market in Europe. Calculating the local Hurst exponent for the WIG time series we find an interesting dependence between the behavior...
0708.0361
Why the relational data model can be considered as a formal basis for group operations in object-oriented systems
cs.DB
Relational data model defines a specification of a type "relation". However, its simplicity does not mean that the system implementing this model must operate with structures having the same simplicity. We consider two principles allowing create a system which combines object-oriented paradigm (OOP) and relational da...
0708.0386
Diversity of MIMO Multihop Relay Channels
cs.IT math.IT
We consider slow fading relay channels with a single multi-antenna source-destination terminal pair. The source signal arrives at the destination via N hops through N-1 layers of relays. We analyze the diversity of such channels with fixed network size at high SNR. In the clustered case where the relays within the sa...
0708.0495
Virtual Manufacturing : Tools for improving Design and Production
cs.RO physics.class-ph
The research area "Virtual Manufacturing" can be defined as an integrated manufacturing environment which can enhance one or several levels of decision and control in manufacturing process. Several domains can be addressed: Product and Process Design, Process and Production Planning, Machine Tool, Robot and Manufactu...
0708.0505
A preliminary analysis on metaheuristics methods applied to the Haplotype Inference Problem
cs.AI cs.CE cs.DM q-bio.QM
Haplotype Inference is a challenging problem in bioinformatics that consists in inferring the basic genetic constitution of diploid organisms on the basis of their genotype. This information allows researchers to perform association studies for the genetic variants involved in diseases and the individual responses to...
0708.0607
Real-time control and monitoring system for LIPI's Public Cluster
cs.DC cs.RO
We have developed a monitoring and control system for LIPI's Public Cluster. The system consists of microcontrollers and full web-based user interfaces for daily operation. It is argued that, due to its special natures, the cluster requires fully dedicated and self developed control and monitoring system. We discuss ...
0708.0648
Auction-Based Distributed Resource Allocation for Cooperation Transmission in Wireless Networks
cs.IT math.IT
Cooperative transmission can greatly improve communication system performance by taking advantage of the broadcast nature of wireless channels. Most previous work on resource allocation for cooperation transmission is based on centralized control. In this paper, we propose two share auction mechanisms, the SNR auctio...
0708.0654
Structure or Noise?
physics.data-an cond-mat.stat-mech cs.IT cs.LG math-ph math.IT math.MP math.ST nlin.CD stat.TH
We show how rate-distortion theory provides a mechanism for automated theory building by naturally distinguishing between regularity and randomness. We start from the simple principle that model variables should, as much as possible, render the future and past conditionally independent. From this, we construct an obj...
0708.0694
Reconstruction of Protein-Protein Interaction Pathways by Mining Subject-Verb-Objects Intermediates
cs.IR cs.CL cs.DL
The exponential increase in publication rate of new articles is limiting access of researchers to relevant literature. This has prompted the use of text mining tools to extract key biological information. Previous studies have reported extensive modification of existing generic text processors to process biological t...
0708.0741
Characterising Web Site Link Structure
cs.IR
The topological structures of the Internet and the Web have received considerable attention. However, there has been little research on the topological properties of individual web sites. In this paper, we consider whether web sites (as opposed to the entire Web) exhibit structural similarities. To do so, we exhausti...
0708.0805
Cooperative Beamforming for Wireless Ad Hoc Networks
cs.IT math.IT
Via collaborative beamforming, nodes in a wireless network are able to transmit a common message over long distances in an energy efficient fashion. However, the process of making available the same message to all collaborating nodes introduces delays. In this paper, a MAC-PHY cross-layer scheme is proposed that enab...
0708.0846
Cooperative game theory and the Gaussian interference channel
cs.IT cs.GT math.IT
In this paper we discuss the use of cooperative game theory for analyzing interference channels. We extend our previous work, to games with N players as well as frequency selective channels and joint TDM/FDM strategies. We show that the Nash bargaining solution can be computed using convex optimization techniques. ...
0708.0850
Relations between random coding exponents and the statistical physics of random codes
cs.IT math.IT
The partition function pertaining to finite--temperature decoding of a (typical) randomly chosen code is known to have three types of behavior, corresponding to three phases in the plane of rate vs. temperature: the {\it ferromagnetic phase}, corresponding to correct decoding, the {\it paramagnetic phase}, of complet...
0708.0905
Permutation Decoding and the Stopping Redundancy Hierarchy of Cyclic and Extended Cyclic Codes
cs.IT math.IT
We introduce the notion of the stopping redundancy hierarchy of a linear block code as a measure of the trade-off between performance and complexity of iterative decoding for the binary erasure channel. We derive lower and upper bounds for the stopping redundancy hierarchy via Lovasz's Local Lemma and Bonferroni-type...
0708.0927
Modeling Visual Information Processing in Brain: A Computer Vision Point of View and Approach
cs.AI cs.CV
We live in the Information Age, and information has become a critically important component of our life. The success of the Internet made huge amounts of it easily available and accessible to everyone. To keep the flow of this information manageable, means for its faultless circulation and effective handling have bec...
0708.1037
A Formulation of the Channel Capacity of Multiple-Access Channel
cs.IT math.IT
The necessary and sufficient condition of the channel capacity is rigorously formulated for the N-user discrete memoryless multiple-access channel (MAC). The essence of the formulation is to invoke an {\em elementary} MAC where sizes of input alphabets are not greater than the size of output alphabet. The main object...
0708.1049
An Interval Analysis Based Study for the Design and the Comparison of 3-DOF Parallel Kinematic Machines
cs.RO
This paper addresses an interval analysis based study that is applied to the design and the comparison of 3-DOF parallel kinematic machines. Two design criteria are used, (i) a regular workspace shape and, (ii) a kinetostatic performance index that needs to be as homogeneous as possible throughout the workspace. The ...
0708.1078
Nearly MDS expander codes with reduced alphabet size
cs.IT math.IT
Recently, Roth and Skachek proposed two methods for constructing nearly maximum-distance separable (MDS) expander codes. We show that through the simple modification of using mixed-alphabet codes derived from MDS codes as constituent codes in their code designs, one can obtain nearly MDS codes of significantly smalle...
0708.1116
A variant of the Recoil Growth algorithm to generate multi-polymer systems
cs.CE cond-mat.stat-mech
The Recoil Growth algorithm, proposed in 1999 by Consta et al., is one of the most efficient algorithm available in the literature to sample from a multi-polymer system. Such problems are closely related to the generation of self-avoiding paths. In this paper, we study a variant of the original Recoil Growth algorith...
0708.1150
A Practical Ontology for the Large-Scale Modeling of Scholarly Artifacts and their Usage
cs.DL cs.AI
The large-scale analysis of scholarly artifact usage is constrained primarily by current practices in usage data archiving, privacy issues concerned with the dissemination of usage data, and the lack of a practical ontology for modeling the usage domain. As a remedy to the third constraint, this article presents a sc...
0708.1179
Diversity-Multiplexing Tradeoff of Asynchronous Cooperative Diversity in Wireless Networks
cs.IT math.IT
Synchronization of relay nodes is an important and critical issue in exploiting cooperative diversity in wireless networks. In this paper, two asynchronous cooperative diversity schemes are proposed, namely, distributed delay diversity and asynchronous space-time coded cooperative diversity schemes. In terms of the o...
0708.1242
Cost-minimising strategies for data labelling : optimal stopping and active learning
cs.LG
Supervised learning deals with the inference of a distribution over an output or label space $\CY$ conditioned on points in an observation space $\CX$, given a training dataset $D$ of pairs in $\CX \times \CY$. However, in a lot of applications of interest, acquisition of large amounts of observations is easy, while ...
0708.1343
A Matrix Ring Description for Cyclic Convolutional Codes
cs.IT math.IT math.RA
In this paper, we study convolutional codes with a specific cyclic structure. By definition, these codes are left ideals in a certain skew polynomial ring. Using that the skew polynomial ring is isomorphic to a matrix ring we can describe the algebraic parameters of the codes in a more accessible way. We show that th...
0708.1362
Physical limits of inference
cond-mat.stat-mech cs.CC cs.IT gr-qc math.IT
I show that physical devices that perform observation, prediction, or recollection share an underlying mathematical structure. I call devices with that structure "inference devices". I present a set of existence and impossibility results concerning inference devices. These results hold independent of the precise phys...
0708.1503
Defensive forecasting for optimal prediction with expert advice
cs.LG
The method of defensive forecasting is applied to the problem of prediction with expert advice for binary outcomes. It turns out that defensive forecasting is not only competitive with the Aggregating Algorithm but also handles the case of "second-guessing" experts, whose advice depends on the learner's prediction; t...
0708.1527
A Data-Parallel Version of Aleph
cs.AI cs.DC
This is to present work on modifying the Aleph ILP system so that it evaluates the hypothesised clauses in parallel by distributing the data-set among the nodes of a parallel or distributed machine. The paper briefly discusses MPI, the interface used to access message- passing libraries for parallel computers and clu...
0708.1558
Construction of a 3-Dimensional MDS code
cs.IT math.IT
In this paper, we describe a procedure for constructing $q$--ary $[N,3,N-2]$--MDS codes, of length $N\leq q+1$ (for $q$ odd) or $N\leq q+2$ (for $q$ even), using a set of non--degenerate Hermitian forms in $PG(2,q^2)$.
0708.1564
Learning Phonotactics Using ILP
cs.CL
This paper describes experiments on learning Dutch phonotactic rules using Inductive Logic Programming, a machine learning discipline based on inductive logical operators. Two different ways of approaching the problem are experimented with, and compared against each other as well as with related work on the task. The...
0708.1580
Optimal Causal Inference: Estimating Stored Information and Approximating Causal Architecture
cs.IT cond-mat.stat-mech cs.LG math.IT math.ST stat.TH
We introduce an approach to inferring the causal architecture of stochastic dynamical systems that extends rate distortion theory to use causal shielding---a natural principle of learning. We study two distinct cases of causal inference: optimal causal filtering and optimal causal estimation. Filtering corresponds ...
0708.1593
Updating Probabilities with Data and Moments
physics.data-an cs.IT math.IT math.ST physics.comp-ph physics.pop-ph stat.AP stat.CO stat.ME stat.TH
We use the method of Maximum (relative) Entropy to process information in the form of observed data and moment constraints. The generic "canonical" form of the posterior distribution for the problem of simultaneous updating with data and moments is obtained. We discuss the general problem of non-commuting constraints...
0708.1818
Computational Simulation and 3D Virtual Reality Engineering Tools for Dynamical Modeling and Imaging of Composite Nanomaterials
cs.CE cond-mat.other
An adventure at engineering design and modeling is possible with a Virtual Reality Environment (VRE) that uses multiple computer-generated media to let a user experience situations that are temporally and spatially prohibiting. In this paper, an approach to developing some advanced architecture and modeling tools is ...
0708.1859
Multiple-Description Coding by Dithered Delta-Sigma Quantization
cs.IT math.IT
We address the connection between the multiple-description (MD) problem and Delta-Sigma quantization. The inherent redundancy due to oversampling in Delta-Sigma quantization, and the simple linear-additive noise model resulting from dithered lattice quantization, allow us to construct a symmetric and time-invariant M...
0708.1877
A nearly tight memory-redundancy trade-off for one-pass compression
cs.IT math.IT
Let $s$ be a string of length $n$ over an alphabet of constant size $\sigma$ and let $c$ and $\epsilon$ be constants with (1 \geq c \geq 0) and (\epsilon > 0). Using (O (n)) time, (O (n^c)) bits of memory and one pass we can always encode $s$ in (n H_k (s) + O (\sigma^k n^{1 - c + \epsilon})) bits for all integers (k...
0708.1964
Solving the subset-sum problem with a light-based device
cs.AR cs.AI cs.DC
We propose a special computational device which uses light rays for solving the subset-sum problem. The device has a graph-like representation and the light is traversing it by following the routes given by the connections between nodes. The nodes are connected by arcs in a special way which lets us to generate all p...
0708.2021
Who is the best connected EC researcher? Centrality analysis of the complex network of authors in evolutionary computation
cs.CY cs.NE
Co-authorship graphs (that is, the graph of authors linked by co-authorship of papers) are complex networks, which expresses the dynamics of a complex system. Only recently its study has started to draw interest from the EC community, the first paper dealing with it having been published two years ago. In this paper ...
0708.2026
Derivative of BICM Mutual Information
cs.IT math.IT
In this letter we determine the derivative of the mutual information corresponding to bit-interleaved coded modulation systems. The derivative follows as a linear combination of minimum-mean-squared error functions of coded modulation sets. The result finds applications to the analysis of communications systems in th...
0708.2076
Repairing Inconsistent XML Write-Access Control Policies
cs.DB
XML access control policies involving updates may contain security flaws, here called inconsistencies, in which a forbidden operation may be simulated by performing a sequence of allowed operations. This paper investigates the problem of deciding whether a policy is consistent, and if not, how its inconsistencies can...
0708.2084
Empirical entropy in context
cs.IT math.IT
We trace the history of empirical entropy, touching briefly on its relation to Markov processes, normal numbers, Shannon entropy, the Chomsky hierarchy, Kolmogorov complexity, Ziv-Lempel compression, de Bruijn sequences and stochastic complexity.
0708.2173
Provenance as Dependency Analysis
cs.DB cs.PL
Provenance is information recording the source, derivation, or history of some information. Provenance tracking has been studied in a variety of settings; however, although many design points have been explored, the mathematical or semantic foundations of data provenance have received comparatively little attention. ...
0708.2213
Moderate Growth Time Series for Dynamic Combinatorics Modelisation
cs.SC cs.MA math.CO
Here, we present a family of time series with a simple growth constraint. This family can be the basis of a model to apply to emerging computation in business and micro-economy where global functions can be expressed from local rules. We explicit a double statistics on these series which allows to establish a one-to-...
0708.2270
Capacity of the Degraded Half-Duplex Relay Channel
cs.IT math.IT
A discrete memoryless half-duplex relay channel is constructed from a broadcast channel from the source to the relay and destination and a multiple access channel from the source and relay to the destination. When the relay listens, the channel operates in the broadcast mode. The channel switches to the multiple acce...
0708.2273
Opportunism in Multiuser Relay Channels: Scheduling, Routing and Spectrum Reuse
cs.IT math.IT
In order to understand the key merits of multiuser diversity techniques in relay-assisted cellular multihop networks, this paper analyzes the spectral efficiency of opportunistic (i.e., channel-aware) scheduling algorithms over a fading multiuser relay channel with $K$ users in the asymptotic regime of large (but fin...
0708.2303
Compositional Semantics Grounded in Commonsense Metaphysics
cs.AI cs.CL
We argue for a compositional semantics grounded in a strongly typed ontology that reflects our commonsense view of the world and the way we talk about it in ordinary language. Assuming the existence of such a structure, we show that the semantics of various natural language phenomena may become nearly trivial.
0708.2310
Benefiting from Disorder: Source Coding for Unordered Data
cs.IT math.IT
The order of letters is not always relevant in a communication task. This paper discusses the implications of order irrelevance on source coding, presenting results in several major branches of source coding theory: lossless coding, universal lossless coding, rate-distortion, high-rate quantization, and universal los...
0708.2319
On Semimeasures Predicting Martin-Loef Random Sequences
cs.IT cs.LG math.IT math.PR
Solomonoff's central result on induction is that the posterior of a universal semimeasure M converges rapidly and with probability 1 to the true sequence generating posterior mu, if the latter is computable. Hence, M is eligible as a universal sequence predictor in case of unknown mu. Despite some nearby results and ...
0708.2353
Continuous and randomized defensive forecasting: unified view
cs.LG
Defensive forecasting is a method of transforming laws of probability (stated in game-theoretic terms as strategies for Sceptic) into forecasting algorithms. There are two known varieties of defensive forecasting: "continuous", in which Sceptic's moves are assumed to depend on the forecasts in a (semi)continuous mann...
0708.2432
A structure from motion inequality
cs.CV cs.AI
We state an elementary inequality for the structure from motion problem for m cameras and n points. This structure from motion inequality relates space dimension, camera parameter dimension, the number of cameras and number points and global symmetry properties and provides a rigorous criterion for which reconstructi...
0708.2438
On Ullman's theorem in computer vision
cs.CV cs.AI
Both in the plane and in space, we invert the nonlinear Ullman transformation for 3 points and 3 orthographic cameras. While Ullman's theorem assures a unique reconstruction modulo a reflection for 3 cameras and 4 points, we find a locally unique reconstruction for 3 cameras and 3 points. Explicit reconstruction form...
0708.2442
Space and camera path reconstruction for omni-directional vision
cs.CV cs.AI
In this paper, we address the inverse problem of reconstructing a scene as well as the camera motion from the image sequence taken by an omni-directional camera. Our structure from motion results give sharp conditions under which the reconstruction is unique. For example, if there are three points in general position...
0708.2456
On the subset sum problem over finite fields
math.NT cs.IT math.IT
The subset sum problem over finite fields is a well-known {\bf NP}-complete problem. It arises naturally from decoding generalized Reed-Solomon codes. In this paper, we study the number of solutions of the subset sum problem from a mathematical point of view. In several interesting cases, we obtain explicit or asympt...
0708.2462
Eigenvalue bounds on the pseudocodeword weight of expander codes
cs.IT math.IT
Four different ways of obtaining low-density parity-check codes from expander graphs are considered. For each case, lower bounds on the minimum stopping set size and the minimum pseudocodeword weight of expander (LDPC) codes are derived. These bounds are compared with the known eigenvalue-based lower bounds on the mi...
0708.2566
Discrete Denoising with Shifts
cs.IT math.IT
We introduce S-DUDE, a new algorithm for denoising DMC-corrupted data. The algorithm, which generalizes the recently introduced DUDE (Discrete Universal DEnoiser) of Weissman et al., aims to compete with a genie that has access, in addition to the noisy data, also to the underlying clean data, and can choose to switc...
0708.2575
Rateless Coding for Gaussian Channels
cs.IT math.IT
A rateless code-i.e., a rate-compatible family of codes-has the property that codewords of the higher rate codes are prefixes of those of the lower rate ones. A perfect family of such codes is one in which each of the codes in the family is capacity-achieving. We show by construction that perfect rateless codes with ...
0708.2686
The universal evolutionary computer based on super-recursive algorithms of evolvability
cs.NE
This work exposes which mechanisms and procesess in the Nature of evolution compute a function not computable by Turing machine. The computer with intelligence that is not higher than one bacteria population could have, but with efficency to solve the problems that are non-computable by Turing machine is represented....
0708.2717
Aggregation Languages for Moving Object and Places of Interest Data
cs.DB
We address aggregate queries over GIS data and moving object data, where non-spatial data are stored in a data warehouse. We propose a formal data model and query language to express complex aggregate queries. Next, we study the compression of trajectory data, produced by moving objects, using the notions of stops an...
0708.2732
Secrecy Capacity Region of Binary and Gaussian Multiple Access Channels
cs.IT math.IT
A generalized multiple access channel (GMAC) with one confidential message set is studied, where two users (users 1 and 2) attempt to transmit common information to a destination, and user 1 also has confidential information intended for the destination. Moreover, user 1 wishes to keep its confidential information as...
0708.2733
Secure Communications over Fading Channels
cs.IT math.IT
The fading wire-tap channel is investigated, where the source-to-destination channel and the source-to-wire-tapper channel are corrupted by multiplicative fading gain coefficients in addition to additive Gaussian noise terms. The channel state information is assumed to be known at both the transmitter and the receive...
0708.2784
On a linear code from a configuration of affine lines
cs.IT cs.DM math.AG math.IT
We will show how to obtain a linear code from a configuration of affine lines in general position and a suitable set of rational points. We will also explain a new decoding algorithm based on the configuration, which seems to be quite effective.
0708.2788
Integrating users' needs into multimedia information retrieval system
cs.IR
The exponential growth of multimedia information and the development of various communication media generated new problems at various levels including the rate of flow of information, problems of storage and management. The difficulty which arises is no longer the existence of information but rather the access to thi...
0708.2804
On Fast-Decodable Space-Time Block Codes
cs.IT math.IT
We focus on full-rate, fast-decodable space-time block codes (STBCs) for 2x2 and 4x2 multiple-input multiple-output (MIMO) transmission. We first derive conditions for reduced-complexity maximum-likelihood decoding, and apply them to a unified analysis of two families of 2x2 STBCs that were recently proposed. In part...
0708.2893
Fast Recursive Coding Based on Grouping of Symbols
cs.IT math.IT
A novel fast recursive coding technique is proposed. It operates with only integer values not longer 8 bits and is multiplication free. Recursion the algorithm is based on indirectly provides rather effective coding of symbols for very large alphabets. The code length for the proposed technique can be up to 20-30% le...
0708.2911
Optimal Sequential Frame Synchronization
cs.IT math.IT
We consider the `one-shot frame synchronization problem' where a decoder wants to locate a sync pattern at the output of a channel on the basis of sequential observations. We assume that the sync pattern of length N starts being emitted at a random time within some interval of size A, that characterizes the asynchron...
0708.2974
The Fuzzy Vault for fingerprints is Vulnerable to Brute Force Attack
cs.CV cs.CR
The \textit{fuzzy vault} approach is one of the best studied and well accepted ideas for binding cryptographic security into biometric authentication. The vault has been implemented in connection with fingerprint data by Uludag and Jain. We show that this instance of the vault is vulnerable to brute force attack. An ...
0708.3019
Single-Symbol ML Decodable Distributed STBCs for Partially-Coherent Cooperative Networks
cs.IT math.IT
Space-time block codes (STBCs) that are single-symbol decodable (SSD) in a co-located multiple antenna setting need not be SSD in a distributed cooperative communication setting. A relay network with N relays and a single source-destination pair is called a partially-coherent relay channel (PCRC) if the destination h...
0708.3048
Identifying Small Mean Reverting Portfolios
cs.CE
Given multivariate time series, we study the problem of forming portfolios with maximum mean reversion while constraining the number of assets in these portfolios. We show that it can be formulated as a sparse canonical correlation analysis and study various algorithms to solve the corresponding sparse generalized ei...
0708.3057
Voice Service Support in Mobile Ad Hoc Networks
cs.IT cs.NI math.IT
Mobile ad hoc networks are expected to support voice traffic. The requirement for small delay and jitter of voice traffic poses a significant challenge for medium access control (MAC) in such networks. User mobility makes it more complex due to the associated dynamic path attenuation. In this paper, a MAC scheme for ...
0708.3070
Network Coding Capacity of Random Wireless Networks under a Signal-to-Interference-and-Noise Model
cs.IT math.IT
In this paper, we study network coding capacity for random wireless networks. Previous work on network coding capacity for wired and wireless networks have focused on the case where the capacities of links in the network are independent. In this paper, we consider a more realistic model, where wireless networks are m...
0708.3127
Question on Conditional Entropy
cs.IT math.IT
The problems of conditional entropy's definition and the formula to compute conditional entropy are analyzed from various perspectives, and the corrected computing formula is presented. Examples are given to prove the conclusion that conditional entropy never be increased is not absolute, thus the representation that...
0708.3220
Optimal strategies in the average consensus problem
cs.MA cs.NI math.OC
We prove that for a set of communicating agents to compute the average of their initial positions (average consensus problem), the optimal topology of communication is given by a de Bruijn's graph. Consensus is then reached in a finitely many steps. A more general family of strategies, constructed by block Kronecker ...
0708.3226
A Dichotomy Theorem for General Minimum Cost Homomorphism Problem
cs.LG cs.CC
In the constraint satisfaction problem ($CSP$), the aim is to find an assignment of values to a set of variables subject to specified constraints. In the minimum cost homomorphism problem ($MinHom$), one is additionally given weights $c_{va}$ for every variable $v$ and value $a$, and the aim is to find an assignment ...
0708.3259
Fast evaluation of union-intersection expressions
cs.DS cs.DB cs.IR
We show how to represent sets in a linear space data structure such that expressions involving unions and intersections of sets can be computed in a worst-case efficient way. This problem has applications in e.g. information retrieval and database systems. We mainly consider the RAM model of computation, and sets of ...
0708.3381
Architecture Optimization of a 3-DOF Translational Parallel Mechanism for Machining Applications, the Orthoglide
cs.RO
This paper addresses the architecture optimization of a 3-DOF translational parallel mechanism designed for machining applications. The design optimization is conducted on the basis of a prescribed Cartesian workspace with prescribed kinetostatic performances. The resulting machine, the Orthoglide, features three fix...
0708.3387
The Impact of Noise Correlation and Channel Phase Information on the Data-Rate of the Single-Symbol ML Decodable Distributed STBCs
cs.IT math.IT
Very recently, we proposed the row-monomial distributed orthogonal space-time block codes (DOSTBCs) and showed that the row-monomial DOSTBCs achieved approximately twice higher bandwidth efficiency than the repetitionbased cooperative strategy [1]. However, we imposed two limitations on the row-monomial DOSTBCs. The ...
0708.3463
A Neural Networks Model of the Venezuelan Economy
cs.CE cs.NE
Besides an indicator of the GDP, the Central Bank of Venezuela generates the so called Monthly Economic Activity General Indicator. The a priori knowledge of this indicator, which represents and sometimes even anticipates the economy's fluctuations, could be helpful in developing public policies and in investment dec...
0708.3464
A Non Parametric Study of the Volatility of the Economy as a Country Risk Predictor
cs.CE cs.NE
This paper intends to explain Venezuela's country spread behavior through the Neural Networks analysis of a monthly economic activity general index of economic indicators constructed by the Central Bank of Venezuela, a measure of the shocks affecting country risk of emerging markets and the U.S. short term interest r...
0708.3465
An Early Warning System for Bankruptcy Prediction: lessons from the Venezuelan Bank Crisis
cs.CE
During 1993-94 Venezuela experienced a severe banking crisis which ended up with 18 commercial banks intervened by the government. Here we develop an early warning system for detecting credit related bankruptcy through discriminant functions developed on financial and macroeconomic data predating the crisis. A robust...
0708.3499
Comparison of Tree-Child Phylogenetic Networks
q-bio.PE cs.CE cs.DM
Phylogenetic networks are a generalization of phylogenetic trees that allow for the representation of non-treelike evolutionary events, like recombination, hybridization, or lateral gene transfer. In this paper, we present and study a new class of phylogenetic networks, called tree-child phylogenetic networks, where ...
0708.3531
Networked Multiple Description Estimation and Compression with Resource Scalability
cs.IT math.IT
We present a joint source-channel multiple description (JSC-MD) framework for resource-constrained network communications (e.g., sensor networks), in which one or many deprived encoders communicate a Markov source against bit errors and erasure errors to many heterogeneous decoders, some powerful and some deprived. T...
0708.3567
On the Distortion of the Eigenvalue Spectrum in MIMO Amplify-and-Forward Multi-Hop Channels
cs.IT math.IT
Consider a wireless MIMO multi-hop channel with n_s non-cooperating source antennas and n_d fully cooperating destination antennas, as well as L clusters containing k non-cooperating relay antennas each. The source signal traverses all L clusters of relay antennas, before it reaches the destination. When relay antenn...
0708.3573
On the Outage Capacity of a Practical Decoder Accounting for Channel Estimation Inaccuracies
cs.IT math.IT
The optimal decoder achieving the outage capacity under imperfect channel estimation is investigated. First, by searching into the family of nearest neighbor decoders, which can be easily implemented on most practical coded modulation systems, we derive a decoding metric that minimizes the average of the transmission...
0708.3607
Parametric stiffness analysis of the Orthoglide
cs.RO
This paper presents a parametric stiffness analysis of the Orthoglide. A compliant modeling and a symbolic expression of the stiffness matrix are conducted. This allows a simple systematic analysis of the influence of the geometric design parameters and to quickly identify the critical link parameters. Our symbolic m...
0708.3613
Kinematics and Workspace Analysis of a Three-Axis Parallel Manipulator: the Orthoglide
cs.RO
The paper addresses kinematic and geometrical aspects of the Orthoglide, a three-DOF parallel mechanism. This machine consists of three fixed linear joints, which are mounted orthogonally, three identical legs and a mobile platform, which moves in the Cartesian x-y-z space with fixed orientation. New solutions to sol...