OpenRaiser/Intern-Atlas huggingface dataset:
Simulation Platform for Wireless Sensor Networks Based on Impulse Radio Ultra Wide Band
Venue: arXiv cs.NI 2010
Year: 2010

Impulse Radio Ultra Wide Band (IR-UWB) is a promising technology to address Wireless Sensor Network (WSN) constraints. However, existing network simulation tools do not provide a complete WSN simulation architecture, with the IR-UWB specificities at the PHYsical (PHY) and the Medium Access Control (MAC) layers. In this paper, we propose a WSN simulation architecture based on the IR-UWB technique. At the PHY layer, we take into account the pulse collision by dealing with the pulse propagation delay. We also modelled MAC protocols specific to IRUWB, for WSN applications. To completely fit the WSN simulation requirements, we propose a generic and reusable sensor and sensing channel model. Most of the WSN application performances can be evaluated thanks to the proposed simulation architecture. The proposed models are implemented on a scalable and well known network simulator: Global Mobile Information System Simulator (GloMoSim). However, they can be reused for all other packet based simulation platforms.
An Optimal Algorithm for the Indirect Covering Subtree Problem
Venue: arXiv cs.DS 2010
Year: 2010

We consider the indirect covering subtree problem (Kim et al., 1996). The input is an edge weighted tree graph along with customers located at the nodes. Each customer is associated with a radius and a penalty. The goal is to locate a tree-shaped facility such that the sum of setup and penalty cost is minimized. The setup cost equals the sum of edge lengths taken by the facility and the penalty cost is the sum of penalties of all customers whose distance to the facility exceeds their radius. The indirect covering subtree problem generalizes the single maximum coverage location problem on trees where the facility is a node rather than a subtree. Indirect covering subtree can be solved in $O(n\log^2 n)$ time (Kim et al., 1996). A slightly faster algorithm for single maximum coverage location with a running time of $O(n\log^2n/\log\log n)$ has been provided (Spoerhase and Wirth, 2009). We achieve time $O(n\log n)$ for indirect covering subtree thereby providing the fastest known algorithm for both problems. Our result implies also faster algorithms for competitive location problems such as $(1,X)$-medianoid and $(1,p)$-centroid on trees. We complement our result by a lower bound of $Ω(n\log n)$ for single maximum coverage location and $(1,X)$-medianoid on a real-number RAM model showing that our algorithm is optimal in running time.
IR-UWB Channel Capacity for Analog and Mostly Digital Implementation
Venue: arXiv cs.NI 2010
Year: 2010

The impact of the type of implementation is considered on the IR-UWB channel capacity. This study is lead for analog and mostly digital implementation. Key parameters and theirs impacts on the channel capacity are exposed in each case: data converters for mostly digital implementations and pulse generators capabilities for analog implementations. These two implementations are compared from a data rate point of view. Their behaviors regarding an increase of the operating frequency are also studied
Approximations to the MMI criterion and their effect on lattice-based MMI
Venue: arXiv cs.CL 2010
Year: 2010

Maximum mutual information (MMI) is a model selection criterion used for hidden Markov model (HMM) parameter estimation that was developed more than twenty years ago as a discriminative alternative to the maximum likelihood criterion for HMM-based speech recognition. It has been shown in the speech recognition literature that parameter estimation using the current MMI paradigm, lattice-based MMI, consistently outperforms maximum likelihood estimation, but this is at the expense of undesirable convergence properties. In particular, recognition performance is sensitive to the number of times that the iterative MMI estimation algorithm, extended Baum-Welch, is performed. In fact, too many iterations of extended Baum-Welch will lead to degraded performance, despite the fact that the MMI criterion improves at each iteration. This phenomenon is at variance with the analogous behavior of maximum likelihood estimation -- at least for the HMMs used in speech recognition -- and it has previously been attributed to `over fitting'. In this paper, we present an analysis of lattice-based MMI that demonstrates, first of all, that the asymptotic behavior of lattice-based MMI is much worse than was previously understood, i.e. it does not appear to converge at all, and, second of all, that this is not due to `over fitting'. Instead, we demonstrate that the `over fitting' phenomenon is the result of standard methodology that exacerbates the poor behavior of two key approximations in the lattice-based MMI machinery. We also demonstrate that if we modify the standard methodology to improve the validity of these approximations, then the convergence properties of lattice-based MMI become benign without sacrificing improvements to recognition accuracy.
Polar Codes for the m-User MAC
Venue: arXiv cs.IT 2010
Year: 2010

In this paper, polar codes for the $m$-user multiple access channel (MAC) with binary inputs are constructed. It is shown that Arıkan's polarization technique applied individually to each user transforms independent uses of a $m$-user binary input MAC into successive uses of extremal MACs. This transformation has a number of desirable properties: (i) the `uniform sum rate' of the original MAC is preserved, (ii) the extremal MACs have uniform rate regions that are not only polymatroids but matroids and thus (iii) their uniform sum rate can be reached by each user transmitting either uncoded or fixed bits; in this sense they are easy to communicate over. A polar code can then be constructed with an encoding and decoding complexity of $O(n \log n)$ (where $n$ is the block length), a block error probability of $o(\exp(- n^{1/2 - \e}))$, and capable of achieving the uniform sum rate of any binary input MAC with arbitrary many users. An application of this polar code construction to communicating on the AWGN channel is also discussed.
Towards Social Profile Based Overlays
Venue: arXiv cs.DC 2010
Year: 2010

Online social networking has quickly become one of the most common activities of Internet users. As social networks evolve, they encourage users to share more information, requiring the users, in turn, to place more trust into social networks. Peer-to-peer (P2P) overlays provide an environment that can return ownership of information, trust, and control to the users, away from centralized third-party social networks. In this paper, we present a novel concept, social profile overlays, which enable users to share their profile only with trusted peers in a scalable, reliable, and private manner. Each user's profile consists of a unique private, secure overlay, where members of that overlay have a friendship with the overlay owner. Profile data is made available without regard to the online state of the profile owner through the use of the profile overlay's distributed data store. Privacy and security are enforced through the use of a public key infrastructure (PKI), where the role of certificate authority (CA) is handled by the overlay owner and each member of the overlay has a CA-signed certificate. All members of the social network join a common public or directory overlay facilitating friend discovery and bootstrap connections into profile overlays. We define interfaces and present tools that can be used to implement this system, as well as explore some of the challenges related to it.
MADMX: A Novel Strategy for Maximal Dense Motif Extraction
Venue: arXiv cs.DS 2010
Year: 2010

We develop, analyze and experiment with a new tool, called MADMX, which extracts frequent motifs, possibly including don't care characters, from biological sequences. We introduce density, a simple and flexible measure for bounding the number of don't cares in a motif, defined as the ratio of solid (i.e., different from don't care) characters to the total length of the motif. By extracting only maximal dense motifs, MADMX reduces the output size and improves performance, while enhancing the quality of the discoveries. The efficiency of our approach relies on a newly defined combining operation, dubbed fusion, which allows for the construction of maximal dense motifs in a bottom-up fashion, while avoiding the generation of nonmaximal ones. We provide experimental evidence of the efficiency and the quality of the motifs returned by MADMX
Programming Idioms for Transactional Events
Venue: arXiv cs.PL 2010
Year: 2010

Transactional events (TE) are an extension of Concurrent ML (CML), a programming model for synchronous message-passing. Prior work has focused on TE's formal semantics and its implementation. This paper considers programming idioms, particularly those that vary unexpectedly from the corresponding CML idioms. First, we solve a subtle problem with client-server protocols in TE. Second, we argue that CML's wrap and guard primitives do not translate well to TE, and we suggest useful workarounds. Finally, we discuss how to rewrite CML protocols that use abort actions.
Virtual Machine Support for Many-Core Architectures: Decoupling Abstract from Concrete Concurrency Models
Venue: arXiv cs.DC 2010
Year: 2010

The upcoming many-core architectures require software developers to exploit concurrency to utilize available computational power. Today's high-level language virtual machines (VMs), which are a cornerstone of software development, do not provide sufficient abstraction for concurrency concepts. We analyze concrete and abstract concurrency models and identify the challenges they impose for VMs. To provide sufficient concurrency support in VMs, we propose to integrate concurrency operations into VM instruction sets. Since there will always be VMs optimized for special purposes, our goal is to develop a methodology to design instruction sets with concurrency support. Therefore, we also propose a list of trade-offs that have to be investigated to advise the design of such instruction sets. As a first experiment, we implemented one instruction set extension for shared memory and one for non-shared memory concurrency. From our experimental results, we derived a list of requirements for a full-grown experimental environment for further research.
The WebStand Project
Venue: arXiv cs.DB 2010
Year: 2010

In this paper we present the state of advancement of the French ANR WebStand project. The objective of this project is to construct a customizable XML based warehouse platform to acquire, transform, analyze, store, query and export data from the web, in particular mailing lists, with the final intension of using this data to perform sociological studies focused on social groups of World Wide Web, with a specific emphasis on the temporal aspects of this data. We are currently using this system to analyze the standardization process of the W3C, through its social network of standard setters.
Towards a Heuristic Categorization of Prepositional Phrases in English with WordNet
Venue: arXiv cs.CL 2010
Year: 2010

This document discusses an approach and its rudimentary realization towards automatic classification of PPs; the topic, that has not received as much attention in NLP as NPs and VPs. The approach is a rule-based heuristics outlined in several levels of our research. There are 7 semantic categories of PPs considered in this document that we are able to classify from an annotated corpus.
Dimensionality Reduction: An Empirical Study on the Usability of IFE-CF (Independent Feature Elimination- by C-Correlation and F-Correlation) Measures
Venue: arXiv cs.LG 2010
Year: 2010

The recent increase in dimensionality of data has thrown a great challenge to the existing dimensionality reduction methods in terms of their effectiveness. Dimensionality reduction has emerged as one of the significant preprocessing steps in machine learning applications and has been effective in removing inappropriate data, increasing learning accuracy, and improving comprehensibility. Feature redundancy exercises great influence on the performance of classification process. Towards the better classification performance, this paper addresses the usefulness of truncating the highly correlated and redundant attributes. Here, an effort has been made to verify the utility of dimensionality reduction by applying LVQ (Learning Vector Quantization) method on two Benchmark datasets of 'Pima Indian Diabetic patients' and 'Lung cancer patients'.
Towards Public Key Infrastructure less authentication in Session Initiation Protocol
Venue: arXiv cs.CR 2010
Year: 2010

The Session Initiation Protocol (SIP) has become the most predominant protocol for Voice over Internet Protocol (VoIP) signaling. Security of SIP is an important consideration for VoIP communication as the traffic is transmitted over the insecure IP network. And the authentication process in SIP ranges from pre-shared secret based solutions to Public Key Infrastructure (PKI) based solution. However, due to the limitations in PKI based solutions, some PKI less authentications mechanisms are proposed. This paper aims to present an overview of different authentication methods used in or together with SIP. We start by highlighting the security issues in SIP in the context of VoIP communication. Then we illustrate the current activities regarding the SIP authentication mechanisms including the recent developments in the research community and standardization efforts within the Internet Engineering Task Force (IETF). Finally we analyze the security aspects of these approaches.
Shape-Adaptive Motion Estimation Algorithm for MPEG-4 Video Coding
Venue: arXiv cs.MM 2010
Year: 2010

This paper presents a gradient based motion estimation algorithm based on shape-motion prediction, which takes advantage of the correlation between neighboring Binary Alpha Blocks (BABs), to match with the Mpeg-4 shape coding case and speed up the estimation process. The PSNR and computation time achieved by the proposed algorithm seem to be better than those obtained by most popular motion estimation techniques.
M-Banking Security - a futuristic improved security approach
Venue: arXiv cs.CR 2010
Year: 2010

In last few decades large technology development raised various new needs. Financial sector has also no exception. People are approaching all over the world to fulfill there dreams. Any sector needs to understand changing need of customer. In order to satisfy financial need for customer banks are taking help of new technology such as internet. Only problem remain is of security. The aim of this work is to provide a secure environment in terms of security for transaction by various ways. In order to improve security we are making use of "Steganography" technique in the way never used before. Task of enhancing security include construction of formula for both data encryption and also for hiding pattern. Server should not process any fake request hence concept of custom "Session id" and "Request id" is introduced. Implementation of such a security constraints in banking sector not only help to serve customer in better way but also make customer confident and satisfy.
RFID Applications: An Introductory and Exploratory Study
Venue: arXiv cs.NI 2010
Year: 2010

RFID is not a new technology and has passed through many decades of use in military, airline, library, security, healthcare, sports, animal farms and other areas. Industries use RFID for various applications such as personal/vehicle access control, departmental store security, equipment tracking, baggage, fast food establishments, logistics, etc. The enhancement in RFID technology has brought advantages that are related to resource optimization, increased efficiency within business processes, and enhanced customer care, overall improvements in business operations and healthcare. Our research is part of a big project; its aim is to produce a model for mobile technology implementation of hospital patients' movement process. However, the focus of this paper is to explore the main RFID components, i.e. the tag, antenna and reader. The results of the investigations conducted on the three RFID components will be used to develop our research model.
Unidirectional Error Correcting Codes for Memory Systems: A Comparative Study
Venue: arXiv cs.IT 2010
Year: 2010

In order to achieve fault tolerance, highly reliable system often require the ability to detect errors as soon as they occur and prevent the speared of erroneous information throughout the system. Thus, the need for codes capable of detecting and correcting byte errors are extremely important since many memory systems use b-bit-per-chip organization. Redundancy on the chip must be put to make fault-tolerant design available. This paper examined several methods of computer memory systems, and then a proposed technique is designed to choose a suitable method depending on the organization of memory systems. The constructed codes require a minimum number of check bits with respect to codes used previously, then it is optimized to fit the organization of memory systems according to the requirements for data and byte lengths.
ICT in Universities of the Western Himalayan Region of India II: A Comparative SWOT Analysis
Venue: arXiv cs.OH 2010
Year: 2010

This study presents a comparative SWOT analysis to comprehend the pattern of development of ICT within six universities of western Himalayan region of India. With the objective of achieving quality and excellence in higher education system in the region, this study provides a basis to decision makers to exploit opportunities and minimize the external threats. The SWOT analysis of different universities, placed under three categories, has been undertaken within the four-tier framework used earlier by the authors. Guided by the initiatives of National Mission on Education through ICT (NMEICT) for SWOT analysis, findings of this paper reveal, relative consistency of these three categories of universities, with the earlier study. A few suggestions, as opportunities, with an emphasis on problem solving orientation in higher education, have been made to strengthen the leadership of universities in the field of ICT.
Understanding Formulation of Social Capital in Online Social Network Sites (SNS)
Venue: arXiv cs.OH 2010
Year: 2010

Online communities are the gatherings of like-minded people, brought together in cyberspace by shared interests. The shared interest has hidden social capital aspects and can be of bridging or bonding type. Creating such communities is not a big challenge but sustaining member's participation is. This study examines the formation and maintenance of social capital in social network sites. In addition to assessing bonding and bridging social capital, we explore a dimension of social capital that assesses one's ability to stay connected with members of a previously inhabited community, which we call maintained social capital. Such dimension is enacted here in terms of Hypothesis.
Mod/Resc Parsimony Inference
Venue: arXiv cs.DS 2010
Year: 2010

We address in this paper a new computational biology problem that aims at understanding a mechanism that could potentially be used to genetically manipulate natural insect populations infected by inherited, intra-cellular parasitic bacteria. In this problem, that we denote by \textsc{Mod/Resc Parsimony Inference}, we are given a boolean matrix and the goal is to find two other boolean matrices with a minimum number of columns such that an appropriately defined operation on these matrices gives back the input. We show that this is formally equivalent to the \textsc{Bipartite Biclique Edge Cover} problem and derive some complexity results for our problem using this equivalence. We provide a new, fixed-parameter tractability approach for solving both that slightly improves upon a previously published algorithm for the \textsc{Bipartite Biclique Edge Cover}. Finally, we present experimental results where we applied some of our techniques to a real-life data set.
Pure Nash Equilibria: Complete Characterization of Hard and Easy Graphical Games
Venue: arXiv cs.GT 2010
Year: 2010

We consider the computational complexity of pure Nash equilibria in graphical games. It is known that the problem is NP-complete in general, but tractable (i.e., in P) for special classes of graphs such as those with bounded treewidth. It is then natural to ask: is it possible to characterize all tractable classes of graphs for this problem? In this work, we provide such a characterization for the case of bounded in-degree graphs, thereby resolving the gap between existing hardness and tractability results. In particular, we analyze the complexity of PUREGG(C, -), the problem of deciding the existence of pure Nash equilibria in graphical games whose underlying graphs are restricted to class C. We prove that, under reasonable complexity theoretic assumptions, for every recursively enumerable class C of directed graphs with bounded in-degree, PUREGG(C, -) is in polynomial time if and only if the reduced graphs (the graphs resulting from iterated removal of sinks) of C have bounded treewidth. We also give a characterization for PURECHG(C,-), the problem of deciding the existence of pure Nash equilibria in colored hypergraphical games, a game representation that can express the additional structure that some of the players have identical local utility functions. We show that the tractable classes of bounded-arity colored hypergraphical games are precisely those whose reduced graphs have bounded treewidth modulo homomorphic equivalence. Our proofs make novel use of Grohe's characterization of the complexity of homomorphism problems.
PAPR reduction of space-time and space-frequency coded OFDM systems using active constellation extension
Venue: arXiv cs.IT 2010
Year: 2010

Active Constellation Extension (ACE) is one of techniques introduced for Peak to Average Power Ratio (PAPR) reduction for OFDM systems. In this technique, the constellation points are extended such that the PAPR is minimized but the minimum distance of the constellation points does not decrease. In this paper, an iterative ACE method is extended to spatially encoded OFDM systems. The proposed methods are such that the PAPR is reduced simultaneously at all antennas, while the spatial encoding relationships still hold. It will be shown that the original ACE method can be employed before Space Time Block Coding (STBC). But in case of Space Frequency Block Coding (SFBC), two modified techniques have been proposed. In the first method, the OFDM frame is separated by several subframes and the ACE method is applied to these subframes independently to reduce their corresponding PAPRs. Then the low PAPR subframes are recombined based on SFBC relationships to yield the transmitted signals from different antennas. In the second method, for each iteration, the ACE is applied to the antenna with the maximum PAPR, and the signals of the other antennas are generated from that of this antenna. Simulation results show that both algorithms converge, but the second method outperforms the first one when the number of antennas is increased.
Extensible type checker for parser generation
Venue: arXiv cs.PL 2010
Year: 2010

Parser generators generate translators from language specifications. In many cases, such specifications contain semantic actions written in the same language as the generated code. Since these actions are subject to little static checking, they are usually a source of errors which are discovered only when generated code is compiled. In this paper we propose a parser generator front-end which statically checks semantic actions for typing errors and prevents such errors from appearing in generated code. The type checking procedure is extensible to support many implementation languages. An extension for Java is presented along with an extension for declarative type system descriptions.