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cs/0701160
Supporting Finite Element Analysis with a Relational Database Backend, Part II: Database Design and Access
cs.DB cs.CE
This is Part II of a three article series on using databases for Finite Element Analysis (FEA). It discusses (1) db design, (2) data loading, (3) typical use cases during grid building, (4) typical use cases during simulation (get and put), (5) typical use cases during analysis (also done in Part III) and some perfor...
cs/0701161
Thousands of DebitCredit Transactions-Per-Second: Easy and Inexpensive
cs.DB cs.PF
A $2k computer can execute about 8k transactions per second. This is 80x more than one of the largest US bank's 1970's traffic - it approximates the total US 1970's financial transaction volume. Very modest modern computers can easily solve yesterday's problems.
cs/0701162
A Measure of Transaction Processing 20 Years Later
cs.DB cs.PF
This provides a retrospective of the paper "A Measure of Transaction Processing" published in 1985. It shows that transaction processing peak performance and price-peformance have improved about 100,000x respectively and that sort/sequential performance has approximately doubled each year (so a million fold improveme...
cs/0701163
Using Table Valued Functions in SQL Server 2005 To Implement a Spatial Data Library
cs.DB cs.CE
This article explains how to add spatial search functions (point-near-point and point in polygon) to Microsoft SQL Server 2005 using C# and table-valued functions. It is possible to use this library to add spatial search to your application without writing any special code. The library implements the public-domain C#...
cs/0701164
Indexing the Sphere with the Hierarchical Triangular Mesh
cs.DB cs.DS
We describe a method to subdivide the surface of a sphere into spherical triangles of similar, but not identical, shapes and sizes. The Hierarchical Triangular Mesh (HTM) is a quad-tree that is particularly good at supporting searches at different resolutions, from arc seconds to hemispheres. The subdivision scheme i...
cs/0701165
Petascale Computational Systems
cs.DB cs.AR
Computational science is changing to be data intensive. Super-Computers must be balanced systems; not just CPU farms but also petascale IO and networking arrays. Anyone building CyberInfrastructure should allocate resources to support a balanced Tier-1 through Tier-3 design.
cs/0701166
Empirical Measurements of Disk Failure Rates and Error Rates
cs.DB cs.AR
The SATA advertised bit error rate of one error in 10 terabytes is frightening. We moved 2 PB through low-cost hardware and saw five disk read error events, several controller failures, and many system reboots caused by security patches. We conclude that SATA uncorrectable read errors are not yet a dominant system-fa...
cs/0701167
Large-Scale Query and XMatch, Entering the Parallel Zone
cs.DB cs.CE
Current and future astronomical surveys are producing catalogs with millions and billions of objects. On-line access to such big datasets for data mining and cross-correlation is usually as highly desired as unfeasible. Providing these capabilities is becoming critical for the Virtual Observatory framework. In this p...
cs/0701168
To BLOB or Not To BLOB: Large Object Storage in a Database or a Filesystem?
cs.DB
Application designers often face the question of whether to store large objects in a filesystem or in a database. Often this decision is made for application design simplicity. Sometimes, performance measurements are also used. This paper looks at the question of fragmentation - one of the operational issues that can...
cs/0701169
A Framework for Designing MIMO systems with Decision Feedback Equalization or Tomlinson-Harashima Precoding
cs.IT math.IT
We consider joint transceiver design for general Multiple-Input Multiple-Output communication systems that implement interference (pre-)subtraction, such as those based on Decision Feedback Equalization (DFE) or Tomlinson-Harashima precoding (THP). We develop a unified framework for joint transceiver design by consid...
cs/0701170
Life Under Your Feet: An End-to-End Soil Ecology Sensor Network, Database, Web Server, and Analysis Service
cs.DB cs.CE
Wireless sensor networks can revolutionize soil ecology by providing measurements at temporal and spatial granularities previously impossible. This paper presents a soil monitoring system we developed and deployed at an urban forest in Baltimore as a first step towards realizing this vision. Motes in this network mea...
cs/0701171
The Zones Algorithm for Finding Points-Near-a-Point or Cross-Matching Spatial Datasets
cs.DB cs.DS
Zones index an N-dimensional Euclidian or metric space to efficiently support points-near-a-point queries either within a dataset or between two datasets. The approach uses relational algebra and the B-Tree mechanism found in almost all relational database systems. Hence, the Zones Algorithm gives a portable-relation...
cs/0701172
Cross-Matching Multiple Spatial Observations and Dealing with Missing Data
cs.DB cs.CE
Cross-match spatially clusters and organizes several astronomical point-source measurements from one or more surveys. Ideally, each object would be found in each survey. Unfortunately, the observation conditions and the objects themselves change continually. Even some stationary objects are missing in some observatio...
cs/0701173
SkyServer Traffic Report - The First Five Years
cs.DB cs.CE
The SkyServer is an Internet portal to the Sloan Digital Sky Survey Catalog Archive Server. From 2001 to 2006, there were a million visitors in 3 million sessions generating 170 million Web hits, 16 million ad-hoc SQL queries, and 62 million page views. The site currently averages 35 thousand visitors and 400 thousan...
cs/0701174
A Prototype for Educational Planning Using Course Constraints to Simulate Student Populations
cs.AI cs.CY cs.DS cs.SC
Distance learning universities usually afford their students the flexibility to advance their studies at their own pace. This can lead to a considerable fluctuation of student populations within a program's courses, possibly affecting the academic viability of a program as well as the related required resources. Prov...
cs/0701178
Distributed Detection in Sensor Networks with Limited Range Sensors
cs.IT math.IT
We consider a multi-object detection problem over a sensor network (SNET) with limited range sensors. This problem complements the widely considered decentralized detection problem where all sensors observe the same object. While the necessity for global collaboration is clear in the decentralized detection problem, ...
cs/0701180
Ontology from Local Hierarchical Structure in Text
cs.IR
We study the notion of hierarchy in the context of visualizing textual data and navigating text collections. A formal framework for ``hierarchy'' is given by an ultrametric topology. This provides us with a theoretical foundation for concept hierarchy creation. A major objective is {\em scalable} annotation or labeli...
cs/0701181
A Note on Local Ultrametricity in Text
cs.CL
High dimensional, sparsely populated data spaces have been characterized in terms of ultrametric topology. This implies that there are natural, not necessarily unique, tree or hierarchy structures defined by the ultrametric topology. In this note we study the extent of local ultrametric topology in texts, with the ai...
cs/0701182
Supplement to: Code Spectrum and Reliability Function: Binary Symmetric Channel
cs.IT math.IT
A much simpler proof of Theorem 1 from M.Burnashev "Code spectrum and reliability function: Binary symmetric channel" is presented.
cs/0701184
Structure and Problem Hardness: Goal Asymmetry and DPLL Proofs in<br> SAT-Based Planning
cs.AI
In Verification and in (optimal) AI Planning, a successful method is to formulate the application as boolean satisfiability (SAT), and solve it with state-of-the-art DPLL-based procedures. There is a lack of understanding of why this works so well. Focussing on the Planning context, we identify a form of problem stru...
cs/0701194
Menzerath-Altmann Law for Syntactic Structures in Ukrainian
cs.CL
In the paper, the definition of clause suitable for an automated processing of a Ukrainian text is proposed. The Menzerath-Altmann law is verified on the sentence level and the parameters for the dependences of the clause length counted in words and syllables on the sentence length counted in clauses are calculated f...
cs/0701196
One-bit Distributed Sensing and Coding for Field Estimation in Sensor Networks
cs.IT math.IT
This paper formulates and studies a general distributed field reconstruction problem using a dense network of noisy one-bit randomized scalar quantizers in the presence of additive observation noise of unknown distribution. A constructive quantization, coding, and field reconstruction scheme is developed and an upper...
cs/0701197
On Delayed Sequential Coding of Correlated Sources
cs.IT math.IT
Motivated by video coding applications, the problem of sequential coding of correlated sources with encoding and/or decoding frame-delays is studied. The fundamental tradeoffs between individual frame rates, individual frame distortions, and encoding/decoding frame-delays are derived in terms of a single-letter infor...
cs/0702007
Power Optimal Scheduling for Guaranteed Throughput in Multi-access Fading Channels
cs.IT math.IT
A power optimal scheduling algorithm that guarantees desired throughput and bounded delay to each user is developed for fading multi-access multi-band systems. The optimization is over the joint space of all rate allocation and coding strategies. The proposed scheduling assigns rates on each band based only on the cu...
cs/0702008
MMSE Optimal Algebraic Space-Time Codes
cs.IT math.IT
Design of Space-Time Block Codes (STBCs) for Maximum Likelihood (ML) reception has been predominantly the main focus of researchers. However, the ML decoding complexity of STBCs becomes prohibitive large as the number of transmit and receive antennas increase. Hence it is natural to resort to a suboptimal reception t...
cs/0702009
On Evaluating the Rate-Distortion Function of Sources with Feed-Forward and the Capacity of Channels with Feedback
cs.IT math.IT
We study the problem of computing the rate-distortion function for sources with feed-forward and the capacity for channels with feedback. The formulas (involving directed information) for the optimal rate-distortion function with feed-forward and channel capacity with feedback are multi-letter expressions and cannot ...
cs/0702011
Dealing With Logical Omniscience: Expressiveness and Pragmatics
cs.LO cs.AI
We examine four approaches for dealing with the logical omniscience problem and their potential applicability: the syntactic approach, awareness, algorithmic knowledge, and impossible possible worlds. Although in some settings these approaches are equi-expressive and can capture all epistemic states, in other setting...
cs/0702012
Plagiarism Detection in arXiv
cs.DB cs.DL cs.IR
We describe a large-scale application of methods for finding plagiarism in research document collections. The methods are applied to a collection of 284,834 documents collected by arXiv.org over a 14 year period, covering a few different research disciplines. The methodology efficiently detects a variety of problemat...
cs/0702014
Probabilistic Analysis of Linear Programming Decoding
cs.IT cs.DM math.IT
We initiate the probabilistic analysis of linear programming (LP) decoding of low-density parity-check (LDPC) codes. Specifically, we show that for a random LDPC code ensemble, the linear programming decoder of Feldman et al. succeeds in correcting a constant fraction of errors with high probability. The fraction of ...
cs/0702015
Network Coding for Distributed Storage Systems
cs.IT cs.NI math.IT
Peer-to-peer distributed storage systems provide reliable access to data through redundancy spread over nodes across the Internet. A key goal is to minimize the amount of bandwidth used to maintain that redundancy. Storing a file using an erasure code, in fragments spread across nodes, promises to require less redund...
cs/0702017
Comment on Improved Analysis of List Decoding and Its Application to Convolutional Codes and Turbo Codes
cs.IT math.IT
In a recent paper [1] an improved analysis concerning the analysis of List Decoding was presented. The event that the correct codeword is excluded from the list is central. For the additive white Gaussian noise (AWGN) channel an important quantity is the in [1] called effective Euclidean distance. This was earlier co...
cs/0702018
Estimation of the Rate-Distortion Function
cs.IT math.IT math.ST stat.TH
Motivated by questions in lossy data compression and by theoretical considerations, we examine the problem of estimating the rate-distortion function of an unknown (not necessarily discrete-valued) source from empirical data. Our focus is the behavior of the so-called "plug-in" estimator, which is simply the rate-dis...
cs/0702020
Construction of Minimal Tail-Biting Trellises for Codes over Finite Abelian Groups
cs.IT math.IT
A definition of atomic codeword for a group code is presented. Some properties of atomic codewords of group codes are investigated. Using these properties, it is shown that every minimal tail-biting trellis for a group code over a finite abelian group can be constructed from its characteristic generators, which exten...
cs/0702023
High-rate, Multi-Symbol-Decodable STBCs from Clifford Algebras
cs.IT math.IT
It is well known that Space-Time Block Codes (STBCs) obtained from Orthogonal Designs (ODs) are single-symbol-decodable (SSD) and from Quasi-Orthogonal Designs (QODs) are double-symbol decodable. However, there are SSD codes that are not obtainable from ODs and DSD codes that are not obtainable from QODs. In this pap...
cs/0702024
Searching for low weight pseudo-codewords
cs.IT math.IT
Belief Propagation (BP) and Linear Programming (LP) decodings of Low Density Parity Check (LDPC) codes are discussed. We summarize results of instanton/pseudo-codeword approach developed for analysis of the error-floor domain of the codes. Instantons are special, code and decoding specific, configurations of the chan...
cs/0702025
Algebraic Signal Processing Theory: Cooley-Tukey Type Algorithms for DCTs and DSTs
cs.IT cs.DS math.IT
This paper presents a systematic methodology based on the algebraic theory of signal processing to classify and derive fast algorithms for linear transforms. Instead of manipulating the entries of transform matrices, our approach derives the algorithms by stepwise decomposition of the associated signal models, or pol...
cs/0702028
Uniform and Partially Uniform Redistribution Rules
cs.AI
This short paper introduces two new fusion rules for combining quantitative basic belief assignments. These rules although very simple have not been proposed in literature so far and could serve as useful alternatives because of their low computation cost with respect to the recent advanced Proportional Conflict Redi...
cs/0702030
Optimizing the SINR operating point of spatial networks
cs.IT math.IT
This paper addresses the following question, which is of interest in the design and deployment of a multiuser decentralized network. Given a total system bandwidth of W Hz and a fixed data rate constraint of R bps for each transmission, how many frequency slots N of size W/N should the band be partitioned into to max...
cs/0702031
Quantized vs. Analog Feedback for the MIMO Downlink: A Comparison between Zero-Forcing Based Achievable Rates
cs.IT math.IT
We consider a MIMO fading broadcast channel and compare the achievable ergodic rates when the channel state information at the transmitter is provided by analog noisy feedback or by quantized (digital) feedback. The superiority of digital feedback is shown, with perfect or imperfect CSIR, whenever the number of feedb...
cs/0702033
Bounds on ordered codes and orthogonal arrays
cs.IT math.CO math.IT
We derive new estimates of the size of codes and orthogonal arrays in the ordered Hamming space (the Niederreiter-Rosenbloom-Tsfasman space). We also show that the eigenvalues of the ordered Hamming scheme, the association scheme that describes the combinatorics of the space, are given by the multivariable Krawtchouk...
cs/0702035
New Models for the Correlation in Sensor Data
cs.IT math.IT
In this paper, we propose two new models of spatial correlations in sensor data in a data-gathering sensor network. A particular property of these models is that if a sensor node knows in \textit{how many} bits it needs to transmit its data, then it also knows \textit{which} bits of its data it needs to transmit.
cs/0702037
Evolutionary Approaches to Minimizing Network Coding Resources
cs.NI cs.IT math.IT
We wish to minimize the resources used for network coding while achieving the desired throughput in a multicast scenario. We employ evolutionary approaches, based on a genetic algorithm, that avoid the computational complexity that makes the problem NP-hard. Our experiments show great improvements over the sub-optima...
cs/0702038
Genetic Representations for Evolutionary Minimization of Network Coding Resources
cs.NE cs.NI
We demonstrate how a genetic algorithm solves the problem of minimizing the resources used for network coding, subject to a throughput constraint, in a multicast scenario. A genetic algorithm avoids the computational complexity that makes the problem NP-hard and, for our experiments, greatly improves on sub-optimal s...
cs/0702044
Transmission Capacity of Ad Hoc Networks with Spatial Diversity
cs.IT math.IT
This paper derives the outage probability and transmission capacity of ad hoc wireless networks with nodes employing multiple antenna diversity techniques, for a general class of signal distributions. This analysis allows system performance to be quantified for fading or non-fading environments. The transmission capa...
cs/0702045
Gaussian Interference Channel Capacity to Within One Bit
cs.IT math.IT
The capacity of the two-user Gaussian interference channel has been open for thirty years. The understanding on this problem has been limited. The best known achievable region is due to Han-Kobayashi but its characterization is very complicated. It is also not known how tight the existing outer bounds are. In this wo...
cs/0702050
Permutation Decoding and the Stopping Redundancy Hierarchy of Linear Block Codes
cs.IT math.IT
We investigate the stopping redundancy hierarchy of linear block codes and its connection to permutation decoding techniques. An element in the ordered list of stopping redundancy values represents the smallest number of possibly linearly dependent rows in any parity-check matrix of a code that avoids stopping sets o...
cs/0702051
The Gaussian multiple access wire-tap channel: wireless secrecy and cooperative jamming
cs.IT cs.CR math.IT
We consider the General Gaussian Multiple Access Wire-Tap Channel (GGMAC-WT). In this scenario, multiple users communicate with an intended receiver in the presence of an intelligent and informed eavesdropper. We define two suitable secrecy measures, termed individual and collective, to reflect the confidence in the ...
cs/0702052
On Random Network Coding for Multicast
cs.IT math.IT
Random linear network coding is a particularly decentralized approach to the multicast problem. Use of random network codes introduces a non-zero probability however that some sinks will not be able to successfully decode the required sources. One of the main theoretical motivations for random network codes stems fro...
cs/0702055
On the possibility of making the complete computer model of a human brain
cs.NE
The development of the algorithm of a neural network building by the corresponding parts of a DNA code is discussed.
cs/0702059
Redundancy-Related Bounds on Generalized Huffman Codes
cs.IT math.IT
This paper presents new lower and upper bounds for the compression rate of binary prefix codes optimized over memoryless sources according to various nonlinear codeword length objectives. Like the most well-known redundancy bounds for minimum average redundancy coding - Huffman coding - these are in terms of a form o...
cs/0702063
Entropy vectors and network codes
cs.IT cs.NI math.IT
We consider a network multicast example that relates the solvability of the multicast problem with the existence of an entropy function. As a result, we provide an alternative approach to the proving of the insufficiency of linear (and abelian) network codes and demonstrate the utility of non-Shannon inequalities to ...
cs/0702064
Group characterizable entropy functions
cs.IT math.IT
This paper studies properties of entropy functions that are induced by groups and subgroups. We showed that many information theoretic properties of those group induced entropy functions also have corresponding group theoretic interpretations. Then we propose an extension method to find outer bound for these group in...
cs/0702067
The Haar Wavelet Transform of a Dendrogram: Additional Notes
cs.IR
We consider the wavelet transform of a finite, rooted, node-ranked, $p$-way tree, focusing on the case of binary ($p = 2$) trees. We study a Haar wavelet transform on this tree. Wavelet transforms allow for multiresolution analysis through translation and dilation of a wavelet function. We explore how this works in o...
cs/0702068
Distributed Decision Through Self-Synchronizing Sensor Networks in the Presence of Propagation Delays and Nonreciprocal Channels
cs.IT cs.MA math.IT
In this paper we propose and analyze a distributed algorithm for achieving globally optimal decisions, either estimation or detection, through a self-synchronization mechanism among linearly coupled integrators initialized with local measurements. We model the interaction among the nodes as a directed graph with weig...
cs/0702070
A Practical Approach to Lossy Joint Source-Channel Coding
cs.IT math.IT
This work is devoted to practical joint source channel coding. Although the proposed approach has more general scope, for the sake of clarity we focus on a specific application example, namely, the transmission of digital images over noisy binary-input output-symmetric channels. The basic building blocks of most stat...
cs/0702071
What is needed to exploit knowledge of primary transmissions?
cs.IT math.IT
Recently, Tarokh and others have raised the possibility that a cognitive radio might know the interference signal being transmitted by a strong primary user in a non-causal way, and use this knowledge to increase its data rates. However, there is a subtle difference between knowing the signal transmitted by the prima...
cs/0702072
Logic Programming with Satisfiability
cs.PL cs.AI
This paper presents a Prolog interface to the MiniSat satisfiability solver. Logic program- ming with satisfiability combines the strengths of the two paradigms: logic programming for encoding search problems into satisfiability on the one hand and efficient SAT solving on the other. This synergy between these two ex...
cs/0702073
Tradeoff between decoding complexity and rate for codes on graphs
cs.IT cs.CC math.IT
We consider transmission over a general memoryless channel, with bounded decoding complexity per bit under message passing decoding. We show that the achievable rate is bounded below capacity if there is a finite success in the decoding in a specified number of operations per bit at the decoder for some codes on grap...
cs/0702075
Firebird Database Backup by Serialized Database Table Dump
cs.DB
This paper presents a simple data dump and load utility for Firebird databases which mimics mysqldump in MySQL. This utility, fb_dump and fb_load, for dumping and loading respectively, retrieves each database table using kinterbasdb and serializes the data using marshal module. This utility has two advantages over th...
cs/0702077
Properties of Rank Metric Codes
cs.IT math.IT
This paper investigates general properties of codes with the rank metric. We first investigate asymptotic packing properties of rank metric codes. Then, we study sphere covering properties of rank metric codes, derive bounds on their parameters, and investigate their asymptotic covering properties. Finally, we establ...
cs/0702081
Random Sentences from a Generalized Phrase-Structure Grammar Interpreter
cs.CL
In numerous domains in cognitive science it is often useful to have a source for randomly generated corpora. These corpora may serve as a foundation for artificial stimuli in a learning experiment (e.g., Ellefson & Christiansen, 2000), or as input into computational models (e.g., Christiansen & Dale, 2001). The follo...
cs/0702082
Invariant template matching in systems with spatiotemporal coding: a vote for instability
cs.CV cs.AI
We consider the design of a pattern recognition that matches templates to images, both of which are spatially sampled and encoded as temporal sequences. The image is subject to a combination of various perturbations. These include ones that can be modeled as parameterized uncertainties such as image blur, luminance, ...
cs/0702084
Performance of Ultra-Wideband Impulse Radio in Presence of Impulsive Interference
cs.IT math.IT
We analyze the performance of coherent impulsive-radio (IR) ultra-wideband (UWB) channel in presence of the interference generated by concurrent transmissions of the systems with the same impulsive radio. We derive a novel algorithm, using Monte-Carlo method, to calculate a lower bound on the rate that can be achieve...
cs/0702085
Social Behaviours Applied to P2P Systems: An efficient Algorithm for Resource Organisation
cs.DC cs.IR
P2P systems are a great solution to the problem of distributing resources. The main issue of P2P networks is that searching and retrieving resources shared by peers is usually expensive and does not take into account similarities among peers. In this paper we present preliminary simulations of PROSA, a novel algorith...
cs/0702091
Observable Graphs
cs.MA
An edge-colored directed graph is \emph{observable} if an agent that moves along its edges is able to determine his position in the graph after a sufficiently long observation of the edge colors. When the agent is able to determine his position only from time to time, the graph is said to be \emph{partly observable}....
cs/0702093
Secure Broadcasting
cs.IT math.IT
Wyner's wiretap channel is extended to parallel broadcast channels and fading channels with multiple receivers. In the first part of the paper, we consider the setup of parallel broadcast channels with one sender, multiple intended receivers, and one eavesdropper. We study the situations where the sender broadcasts e...
cs/0702096
Overcoming Hierarchical Difficulty by Hill-Climbing the Building Block Structure
cs.NE cs.AI
The Building Block Hypothesis suggests that Genetic Algorithms (GAs) are well-suited for hierarchical problems, where efficient solving requires proper problem decomposition and assembly of solution from sub-solution with strong non-linear interdependencies. The paper proposes a hill-climber operating over the buildi...
cs/0702097
Avoiding bias in cards cryptography
cs.CR cs.MA
We outline the need for stricter requirements for unconditionally secure cryptographic protocols inspired by the Russian Cards problem. A new requirement CA4 is proposed that checks for bias in single card occurrence in announcements consisting of alternatives for players' holdings of cards. This requirement CA4 is s...
cs/0702099
Discrete Memoryless Interference and Broadcast Channels with Confidential Messages: Secrecy Rate Regions
cs.IT math.IT
We study information-theoretic security for discrete memoryless interference and broadcast channels with independent confidential messages sent to two receivers. Confidential messages are transmitted to their respective receivers with information-theoretic secrecy. That is, each receiver is kept in total ignorance wi...
cs/0702100
A Class of Multi-Channel Cosine Modulated IIR Filter Banks
cs.IT math.IT
This paper presents a class of multi-channel cosine-modulated filter banks satisfying the perfect reconstruction (PR) property using an IIR prototype filter. By imposing a suitable structure on the polyphase filter coefficients, we show that it is possible to greatly simplify the PR condition, while preserving the ca...
cs/0702101
An identity of Chernoff bounds with an interpretation in statistical physics and applications in information theory
cs.IT math.IT
An identity between two versions of the Chernoff bound on the probability a certain large deviations event, is established. This identity has an interpretation in statistical physics, namely, an isothermal equilibrium of a composite system that consists of multiple subsystems of particles. Several information--theore...
cs/0702102
Paging and Registration in Cellular Networks: Jointly Optimal Policies and an Iterative Algorithm
cs.IT cs.NI math.IT
This paper explores optimization of paging and registration policies in cellular networks. Motion is modeled as a discrete-time Markov process, and minimization of the discounted, infinite-horizon average cost is addressed. The structure of jointly optimal paging and registration policies is investigated through the ...
cs/0702104
A Union Bound Approximation for Rapid Performance Evaluation of Punctured Turbo Codes
cs.IT math.IT
In this paper, we present a simple technique to approximate the performance union bound of a punctured turbo code. The bound approximation exploits only those terms of the transfer function that have a major impact on the overall performance. We revisit the structure of the constituent convolutional encoder and we de...
cs/0702105
The Simplest Solution to an Underdetermined System of Linear Equations
cs.IT math.IT
Consider a d*n matrix A, with d<n. The problem of solving for x in y=Ax is underdetermined, and has infinitely many solutions (if there are any). Given y, the minimum Kolmogorov complexity solution (MKCS) of the input x is defined to be an input z (out of many) with minimum Kolmogorov-complexity that satisfies y=Az. ...
cs/0702106
Wild, Wild Wikis: A way forward
cs.IR
Wikis can be considered as public domain knowledge sharing system. They provide opportunity for those who may not have the privilege to publish their thoughts through the traditional methods. They are one of the fastest growing systems of online encyclopaedia. In this study, we consider the importance of wikis as a w...
cs/0702107
AMIEDoT: An annotation model for document tracking and recommendation service
cs.IR
The primary objective of document annotation in whatever form, manual or electronic is to allow those who may not have control to original document to provide personal view on information source. Beyond providing personal assessment to original information sources, we are looking at a situation where annotation made ...
cs/0702108
Orthogonal Codes for Robust Low-Cost Communication
cs.IT math.IT
Orthogonal coding schemes, known to asymptotically achieve the capacity per unit cost (CPUC) for single-user ergodic memoryless channels with a zero-cost input symbol, are investigated for single-user compound memoryless channels, which exhibit uncertainties in their input-output statistical relationships. A minimax ...
cs/0702109
AMIE: An annotation model for information research
cs.IR
The objective of most users for consulting any information database, information warehouse or the internet is to resolve one problem or the other. Available online or offline annotation tools were not conceived with the objective of assisting users in their bid to resolve a decisional problem. Apart from the objectiv...
cs/0702111
Informed Dynamic Scheduling for Belief-Propagation Decoding of LDPC Codes
cs.IT math.IT
Low-Density Parity-Check (LDPC) codes are usually decoded by running an iterative belief-propagation, or message-passing, algorithm over the factor graph of the code. The traditional message-passing schedule consists of updating all the variable nodes in the graph, using the same pre-update information, followed by u...
cs/0702112
The General Gaussian Multiple Access and Two-Way Wire-Tap Channels: Achievable Rates and Cooperative Jamming
cs.IT cs.CR math.IT
The General Gaussian Multiple Access Wire-Tap Channel (GGMAC-WT) and the Gaussian Two-Way Wire-Tap Channel (GTW-WT) are considered. In the GGMAC-WT, multiple users communicate with an intended receiver in the presence of an eavesdropper who receives their signals through another GMAC. In the GTW-WT, two users communi...
cs/0702115
Guessing based on length functions
cs.IT cs.CR math.IT
A guessing wiretapper's performance on a Shannon cipher system is analyzed for a source with memory. Close relationships between guessing functions and length functions are first established. Subsequently, asymptotically optimal encryption and attack strategies are identified and their performances analyzed for sourc...
cs/0702118
Interpolation-based Decoding of Alternant Codes
cs.IT math.IT
We formulate the classical decoding algorithm of alternant codes afresh based on interpolation as in Sudan's list decoding of Reed-Solomon codes, and thus get rid of the key equation and the linear recurring sequences in the theory. The result is a streamlined exposition of the decoding algorithm using a bit of the t...
cs/0702122
Transmitter and Precoding Order Optimization for Nonlinear Downlink Beamforming
cs.IT math.IT
The downlink of a multiple-input multiple output (MIMO) broadcast channel (BC) is considered, where each receiver is equipped with a single antenna and the transmitter performs nonlinear Dirty-Paper Coding (DPC). We present an efficient algorithm that finds the optimum transmit filters and power allocation as well as...
cs/0702126
Efficient Searching and Retrieval of Documents in PROSA
cs.DC cs.IR
Retrieving resources in a distributed environment is more difficult than finding data in centralised databases. In the last decade P2P system arise as new and effective distributed architectures for resource sharing, but searching in such environments could be difficult and time-consuming. In this paper we discuss ef...
cs/0702127
Exploiting social networks dynamics for P2P resource organisation
cs.DC cs.IR
In this paper we present a formal description of PROSA, a P2P resource management system heavily inspired by social networks. Social networks have been deeply studied in the last two decades in order to understand how communities of people arise and grow. It is a widely known result that networks of social relationsh...
cs/0702130
Syndrome Decoding of Reed-Solomon Codes Beyond Half the Minimum Distance based on Shift-Register Synthesis
cs.IT math.IT
In this paper, a new approach for decoding low-rate Reed-Solomon codes beyond half the minimum distance is considered and analyzed. Unlike the Sudan algorithm published in 1997, this new approach is based on multi-sequence shift-register synthesis, which makes it easy to understand and simple to implement. The comput...
cs/0702131
AICA: a New Pair Force Evaluation Method for Parallel Molecular Dynamics in Arbitrary Geometries
cs.CE cs.DC
A new algorithm for calculating intermolecular pair forces in Molecular Dynamics (MD) simulations on a distributed parallel computer is presented. The Arbitrary Interacting Cells Algorithm (AICA) is designed to operate on geometrical domains defined by an unstructured, arbitrary polyhedral mesh, which has been spatia...
cs/0702132
Uplink Capacity and Interference Avoidance for Two-Tier Femtocell Networks
cs.NI cs.IT math.IT
Two-tier femtocell networks-- comprising a conventional macrocellular network plus embedded femtocell hotspots-- offer an economically viable solution to achieving high cellular user capacity and improved coverage. With universal frequency reuse and DS-CDMA transmission however, the ensuing cross-tier cochannel inter...
cs/0702138
On the Maximal Diversity Order of Spatial Multiplexing with Transmit Antenna Selection
cs.IT math.IT
Zhang et. al. recently derived upper and lower bounds on the achievable diversity of an N_R x N_T i.i.d. Rayleigh fading multiple antenna system using transmit antenna selection, spatial multiplexing and a linear receiver structure. For the case of L = 2 transmitting (out of N_T available) antennas the bounds are tig...
cs/0702142
An Optimal Linear Time Algorithm for Quasi-Monotonic Segmentation
cs.DS cs.DB
Monotonicity is a simple yet significant qualitative characteristic. We consider the problem of segmenting an array in up to K segments. We want segments to be as monotonic as possible and to alternate signs. We propose a quality metric for this problem, present an optimal linear time algorithm based on novel formali...
cs/0702143
Attribute Value Reordering For Efficient Hybrid OLAP
cs.DB
The normalization of a data cube is the ordering of the attribute values. For large multidimensional arrays where dense and sparse chunks are stored differently, proper normalization can lead to improved storage efficiency. We show that it is NP-hard to compute an optimal normalization even for 1x3 chunks, although w...
cs/0702144
Slope One Predictors for Online Rating-Based Collaborative Filtering
cs.DB cs.AI
Rating-based collaborative filtering is the process of predicting how a user would rate a given item from other user ratings. We propose three related slope one schemes with predictors of the form f(x) = x + b, which precompute the average difference between the ratings of one item and another for users who rated bot...
cs/0702146
A Local Tree Structure is NOT Sufficient for the Local Optimality of Message-Passing Decoding in Low Density Parity Check Codes
cs.IT math.IT
We address the problem,`Is a local tree structure sufficient for the local optimality of message passing algorithm in low density parity check codes?'.It is shown that the answer is negative. Using this observation, we pinpoint a flaw in the proof of Theorem 1 in the paper `The Capacity of Low-Density Parity-Check Co...
cs/0702147
On the Complexity of Exact Maximum-Likelihood Decoding for Asymptotically Good Low Density Parity Check Codes
cs.IT math.IT
Since the classical work of Berlekamp, McEliece and van Tilborg, it is well known that the problem of exact maximum-likelihood (ML) decoding of general linear codes is NP-hard. In this paper, we show that exact ML decoding of a classs of asymptotically good error correcting codes--expander codes, a special case of lo...
cs/0702148
Linking Microscopic and Macroscopic Models for Evolution: Markov Chain Network Training and Conservation Law Approximations
cs.CE cs.IT cs.NA cs.NE math.IT
In this paper, a general framework for the analysis of a connection between the training of artificial neural networks via the dynamics of Markov chains and the approximation of conservation law equations is proposed. This framework allows us to demonstrate an intrinsic link between microscopic and macroscopic models...
cs/0702149
Coupling Control and Human-Centered Automation in Mathematical Models of Complex Systems
cs.CE cs.AI cs.HC cs.IT math.IT
In this paper we analyze mathematically how human factors can be effectively incorporated into the analysis and control of complex systems. As an example, we focus our discussion around one of the key problems in the Intelligent Transportation Systems (ITS) theory and practice, the problem of speed control, considere...
cs/0702150
A note on rate-distortion functions for nonstationary Gaussian autoregressive processes
cs.IT math.IT
Source coding theorems and Shannon rate-distortion functions were studied for the discrete-time Wiener process by Berger and generalized to nonstationary Gaussian autoregressive processes by Gray and by Hashimoto and Arimoto. Hashimoto and Arimoto provided an example apparently contradicting the methods used in Gray,...
cs/0702154
On the Capacity of the Single Source Multiple Relay Single Destination Mesh Network
cs.IT cs.NI math.IT
In this paper, we derive the information theoretic capacity of a special class of mesh networks. A mesh network is a heterogeneous wireless network in which the transmission among power limited nodes is assisted by powerful relays, which use the same wireless medium. We investigate the mesh network when there is one ...
cs/0702159
Perfect Hashing for Data Management Applications
cs.DS cs.DB
Perfect hash functions can potentially be used to compress data in connection with a variety of data management tasks. Though there has been considerable work on how to construct good perfect hash functions, there is a gap between theory and practice among all previous methods on minimal perfect hashing. On one side,...
cs/0702161
Perfectly Secure Steganography: Capacity, Error Exponents, and Code Constructions
cs.IT cs.CR math.IT
An analysis of steganographic systems subject to the following perfect undetectability condition is presented in this paper. Following embedding of the message into the covertext, the resulting stegotext is required to have exactly the same probability distribution as the covertext. Then no statistical test can relia...