OpenRaiser/Intern-Atlas huggingface dataset:
Process Description of COM Object Life Cycle
Venue: arXiv cs.OS 2009
Year: 2009

The objective of this article is to provide for the reader a basic description of all the steps involved in the COM object life-cycle process. COM is a software technology and process performer. The first section briefly introduces the Component Object Model (COM), considering the process of the COM object life cycle as the baseline of all COM issues. The second part describes in detail the basic steps of the process - client request, server location, object creation, interaction, and disconnection. A brief description is given for the components involved in each step. Finally, the third section provides a brief conclusion summarizing all the process steps.
The SJR indicator: A new indicator of journals' scientific prestige
Venue: arXiv cs.DL 2009
Year: 2009

This paper proposes an indicator of journals' scientific prestige, the SJR indicator, for ranking scholarly journals based on citation weighting schemes and eigenvector centrality to be used in complex and heterogeneous citation networks such Scopus. Its computation methodology is described and the results after implementing the indicator over Scopus 2007 dataset are compared to an ad-hoc Journal Impact Factor both generally and inside specific scientific areas. The results showed that SJR indicator and JIF distributions fitted well to a power law distribution and that both metrics were strongly correlated, although there were also major changes in rank. There was an observable general trend that might indicate that SJR indicator values decreased certain JIF values whose citedeness was greater than would correspond to their scientific influence.
The weighted difference substitutions and Nonnegativity Decision of Forms
Venue: arXiv cs.SC 2009
Year: 2009

In this paper, we study the weighted difference substitutions from geometrical views. First, we give the geometric meanings of the weighted difference substitutions, and introduce the concept of convergence of the sequence of substitution sets. Then it is proven that the sequence of the successive weighted difference substitution sets is convergent. Based on the convergence of the sequence of the successive weighted difference sets, a new, simpler method to prove that if the form F is positive definite on T_n, then the sequence of sets {SDS^m(F)} is positively terminating is presented, which is different from the one given in [11]. That is, we can decide the nonnegativity of a positive definite form by successively running the weighted difference substitutions finite times. Finally, an algorithm for deciding an indefinite form with a counter-example is obtained, and some examples are listed by using the obtained algorithm.
Multicore-aware parallel temporal blocking of stencil codes for shared and distributed memory
Venue: arXiv cs.PF 2009
Year: 2009

New algorithms and optimization techniques are needed to balance the accelerating trend towards bandwidth-starved multicore chips. It is well known that the performance of stencil codes can be improved by temporal blocking, lessening the pressure on the memory interface. We introduce a new pipelined approach that makes explicit use of shared caches in multicore environments and minimizes synchronization and boundary overhead. For clusters of shared-memory nodes we demonstrate how temporal blocking can be employed successfully in a hybrid shared/distributed-memory environment.
Elkan's k-Means for Graphs
Venue: arXiv cs.AI 2009
Year: 2009

This paper extends k-means algorithms from the Euclidean domain to the domain of graphs. To recompute the centroids, we apply subgradient methods for solving the optimization-based formulation of the sample mean of graphs. To accelerate the k-means algorithm for graphs without trading computational time against solution quality, we avoid unnecessary graph distance calculations by exploiting the triangle inequality of the underlying distance metric following Elkan's k-means algorithm proposed in \cite{Elkan03}. In experiments we show that the accelerated k-means algorithm are faster than the standard k-means algorithm for graphs provided there is a cluster structure in the data.
Bit Error Rate is Convex at High SNR
Venue: arXiv cs.IT 2009
Year: 2009

Motivated by a wide-spread use of convex optimization techniques, convexity properties of bit error rate of the maximum likelihood detector operating in the AWGN channel are studied for arbitrary constellations and bit mappings, which may also include coding under maximum-likelihood decoding. Under this generic setting, the pairwise probability of error and bit error rate are shown to be convex functions of the SNR in the high SNR regime with explicitly-determined boundary. The bit error rate is also shown to be a convex function of the noise power in the low noise/high SNR regime.
Google Android: A State-of-the-Art Review of Security Mechanisms
Venue: arXiv cs.CR 2009
Year: 2009

Google's Android is a comprehensive software framework for mobile communication devices (i.e., smartphones, PDAs). The Android framework includes an operating system, middleware and a set of key applications. The incorporation of integrated access services to the Internet on such mobile devices, however, increases their exposure to damages inflicted by various types of malware. This paper provides a comprehensive security assessment of the Android framework and the security mechanisms incorporated into it. A methodological qualitative risk analysis that we conducted identifies the high-risk threats to the framework and any potential danger to information or to the system resulting from vulnerabilities that have been uncovered and exploited. Our review of current academic and commercial solutions in the area of smartphone security yields a list of applied and recommended defense mechanisms for hardening mobile devices in general and the Android in particular. Lastly, we present five major (high-risk) threats to the Android framework and propose security solutions to mitigate them. We conclude by proposing a set of security mechanisms that should be explored and introduced into Android-powered devices.
Inspiration from genetics to promote recognition and protection within ad hoc sensor networks
Venue: arXiv cs.CR 2009
Year: 2009

This work illustrates potentials for recognition within {\em ad hoc} sensor networks if their nodes possess individual inter-related biologically inspired genetic codes. The work takes ideas from natural immune systems protecting organisms from infection. Nodes in the present proposal have individual gene sets fitting into a self organised phylogenetic tree. Members of this population are genetically ''relatives''. Outsiders cannot easily copy or introduce a new node in the network without going through a process of conception between two nodes in the population. Related nodes can locally decide to check each other for their genetic relation without directly revealing their gene sets. A copy/clone of a gene sequence or a random gene set will appear as alien. Nodes go through a cycle of introduction (conception or ''birth'') with parents in the network and later exit from it (''death''). Hence the phylogenetic tree is dynamic or possesses a genetic drift. Typical lifetimes of gene sets and number of offspring from different parents affect this genetic drift and the level of correlation between gene sets. The frequency of mutations similarly affects the gene pool. Correlation between genes of the nodes implies a common secret for cryptographic material for communication and consistency check facilitating intrusion detection and tracing of events. A node can by itself (non-specifically) recognise an adversary if it does not respond properly according to its genes. Nodes can also collaborate to recognise adversaries by communicating response from intruders to check for consistency with the whole gene pool (phylogenetic tree).
Lipschitz Unimodal and Isotonic Regression on Paths and Trees
Venue: arXiv cs.DS 2009
Year: 2009

We describe algorithms for finding the regression of t, a sequence of values, to the closest sequence s by mean squared error, so that s is always increasing (isotonicity) and so the values of two consecutive points do not increase by too much (Lipschitz). The isotonicity constraint can be replaced with a unimodular constraint, where there is exactly one local maximum in s. These algorithm are generalized from sequences of values to trees of values. For each scenario we describe near-linear time algorithms.
Secure Vehicular Communication Systems: Design and Architecture
Venue: arXiv cs.CR 2009
Year: 2009

Significant developments have taken place over the past few years in the area of vehicular communication (VC) systems. Now, it is well understood in the community that security and protection of private user information are a prerequisite for the deployment of the technology. This is so, precisely because the benefits of VC systems, with the mission to enhance transportation safety and efficiency, are at stake. Without the integration of strong and practical security and privacy enhancing mechanisms, VC systems could be disrupted or disabled, even by relatively unsophisticated attackers. We address this problem within the SeVeCom project, having developed a security architecture that provides a comprehensive and practical solution. We present our results in a set of two papers in this issue. In this first one, we analyze threats and types of adversaries, we identify security and privacy requirements, and we present a spectrum of mechanisms to secure VC systems. We provide a solution that can be quickly adopted and deployed. In the second paper, we present our progress towards the implementation of our architecture and results on the performance of the secure VC system, along with a discussion of upcoming research challenges and our related current results.
Optimality in Goal-Dependent Analysis of Sharing
Venue: arXiv cs.PL 2009
Year: 2009

We face the problems of correctness, optimality and precision for the static analysis of logic programs, using the theory of abstract interpretation. We propose a framework with a denotational, goal-dependent semantics equipped with two unification operators for forward unification (calling a procedure) and backward unification (returning from a procedure). The latter is implemented through a matching operation. Our proposal clarifies and unifies many different frameworks and ideas on static analysis of logic programming in a single, formal setting. On the abstract side, we focus on the domain Sharing by Jacobs and Langen and provide the best correct approximation of all the primitive semantic operators, namely, projection, renaming, forward and backward unification. We show that the abstract unification operators are strictly more precise than those in the literature defined over the same abstract domain. In some cases, our operators are more precise than those developed for more complex domains involving linearity and freeness. To appear in Theory and Practice of Logic Programming (TPLP)
Human being is a living random number generator
Venue: arXiv cs.DS 2009
Year: 2009

General wisdom is, mathematical operation is needed to generate number by numbers. It is pointed out that without any mathematical operation true random numbers can be generated by numbers through algorithmic process. It implies that human brain itself is a living true random number generator. Human brain can meet the enormous human demand of true random numbers.
Solving non-uniqueness in agglomerative hierarchical clustering using multidendrograms
Venue: arXiv cs.IR 2009
Year: 2009

In agglomerative hierarchical clustering, pair-group methods suffer from a problem of non-uniqueness when two or more distances between different clusters coincide during the amalgamation process. The traditional approach for solving this drawback has been to take any arbitrary criterion in order to break ties between distances, which results in different hierarchical classifications depending on the criterion followed. In this article we propose a variable-group algorithm that consists in grouping more than two clusters at the same time when ties occur. We give a tree representation for the results of the algorithm, which we call a multidendrogram, as well as a generalization of the Lance and Williams' formula which enables the implementation of the algorithm in a recursive way.
Stationary Algorithmic Probability
Venue: arXiv cs.IT 2009
Year: 2009

Kolmogorov complexity and algorithmic probability are defined only up to an additive resp. multiplicative constant, since their actual values depend on the choice of the universal reference computer. In this paper, we analyze a natural approach to eliminate this machine-dependence. Our method is to assign algorithmic probabilities to the different computers themselves, based on the idea that "unnatural" computers should be hard to emulate. Therefore, we study the Markov process of universal computers randomly emulating each other. The corresponding stationary distribution, if it existed, would give a natural and machine-independent probability measure on the computers, and also on the binary strings. Unfortunately, we show that no stationary distribution exists on the set of all computers; thus, this method cannot eliminate machine-dependence. Moreover, we show that the reason for failure has a clear and interesting physical interpretation, suggesting that every other conceivable attempt to get rid of those additive constants must fail in principle, too. However, we show that restricting to some subclass of computers might help to get rid of some amount of machine-dependence in some situations, and the resulting stationary computer and string probabilities have beautiful properties.
Bounds on ordered codes and orthogonal arrays
Venue: arXiv cs.IT 2009
Year: 2009

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 polynomials, and establish some of their properties.
Efficient Divide-and-Conquer Implementations Of Symmetric FSAs
Venue: arXiv cs.FL 2010
Year: 2010

A deterministic finite-state automaton (FSA) is an abstract sequential machine that reads the symbols comprising an input word one at a time. An FSA is symmetric if its output is independent of the order in which the input symbols are read, i.e., if the output is invariant under permutations of the input. We show how to convert a symmetric FSA A into an automaton-like divide-and-conquer process whose intermediate results are no larger than the size of A's memory. In comparison, a similar result for general FSA's has been long known via functional composition, but entails an exponential increase in memory size. The new result has applications to parallel processing and symmetric FSA networks.
An Algorithm for Road Coloring
Venue: arXiv cs.DM 2010
Year: 2010

A coloring of edges of a finite directed graph turns the graph into finite-state automaton. The synchronizing word of a deterministic automaton is a word in the alphabet of colors (considered as letters) of its edges that maps the automaton to a single state. A coloring of edges of a directed graph of uniform outdegree (constant outdegree of any vertex) is synchronizing if the coloring turns the graph into a deterministic finite automaton possessing a synchronizing word. The road coloring problem is the problem of synchronizing coloring of a directed finite strongly connected graph of uniform outdegree if the greatest common divisor of the lengths of all its cycles is one. The problem posed in 1970 had evoked a noticeable interest among the specialists in the theory of graphs, automata, codes, symbolic dynamics as well as among the wide mathematical community. A polynomial time algorithm of $O(n^3)$ complexity in the most worst case and quadratic in majority of studied cases for the road coloring of the considered graph is presented below. The work is based on recent positive solution of the road coloring problem. The algorithm was implemented in the package TESTAS
Capacity of General Discrete Noiseless Channels
Venue: arXiv cs.IT 2010
Year: 2010

This paper concerns the capacity of the discrete noiseless channel introduced by Shannon. A sufficient condition is given for the capacity to be well-defined. For a general discrete noiseless channel allowing non-integer valued symbol weights, it is shown that the capacity--if well-defined--can be determined from the radius of convergence of its generating function, from the smallest positive pole of its generating function, or from the rightmost real singularity of its complex generating function. A generalisation is given for Pringsheim's Theorem and for the Exponential Growth Formula to generating functions of combinatorial structures with non-integer valued symbol weights.
Performance of LDPC Codes Under Faulty Iterative Decoding
Venue: arXiv cs.IT 2010
Year: 2010

Departing from traditional communication theory where decoding algorithms are assumed to perform without error, a system where noise perturbs both computational devices and communication channels is considered here. This paper studies limits in processing noisy signals with noisy circuits by investigating the effect of noise on standard iterative decoders for low-density parity-check codes. Concentration of decoding performance around its average is shown to hold when noise is introduced into message-passing and local computation. Density evolution equations for simple faulty iterative decoders are derived. In one model, computing nonlinear estimation thresholds shows that performance degrades smoothly as decoder noise increases, but arbitrarily small probability of error is not achievable. Probability of error may be driven to zero in another system model; the decoding threshold again decreases smoothly with decoder noise. As an application of the methods developed, an achievability result for reliable memory systems constructed from unreliable components is provided.
Spatial Interference Cancellation for Multi-Antenna Mobile Ad Hoc Networks
Venue: arXiv cs.IT 2010
Year: 2010

Interference between nodes is a critical impairment in mobile ad hoc networks (MANETs). This paper studies the role of multiple antennas in mitigating such interference. Specifically, a network is studied in which receivers apply zero-forcing beamforming to cancel the strongest interferers. Assuming a network with Poisson distributed transmitters and independent Rayleigh fading channels, the transmission capacity is derived, which gives the maximum number of successful transmissions per unit area. Mathematical tools from stochastic geometry are applied to obtain the asymptotic transmission capacity scaling and characterize the impact of inaccurate channel state information (CSI). It is shown that, if each node cancels L interferers, the transmission capacity decreases as the outage probability to the power of 1/(L+1) as the outage probability vanishes. For fixed outage probability, as L grows, the transmission capacity increases as L to the power of (1-2/alpha) where alpha is the path-loss exponent. Moreover, CSI inaccuracy is shown to have no effect on the transmission capacity scaling as the outage probability vanishes, provided that the CSI training sequence has an appropriate length, which we derived. Numerical results suggest that canceling merely one interferer by each node increases the transmission capacity by an order of magnitude or more, even when the CSI is imperfect.
Polygon Exploration with Time-Discrete Vision
Venue: arXiv cs.CG 2010
Year: 2010

With the advent of autonomous robots with two- and three-dimensional scanning capabilities, classical visibility-based exploration methods from computational geometry have gained in practical importance. However, real-life laser scanning of useful accuracy does not allow the robot to scan continuously while in motion; instead, it has to stop each time it surveys its environment. This requirement was studied by Fekete, Klein and Nuechter for the subproblem of looking around a corner, but until now has not been considered in an online setting for whole polygonal regions. We give the first algorithmic results for this important algorithmic problem that combines stationary art gallery-type aspects with watchman-type issues in an online scenario: We demonstrate that even for orthoconvex polygons, a competitive strategy can be achieved only for limited aspect ratio A (the ratio of the maximum and minimum edge length of the polygon), i.e., for a given lower bound on the size of an edge; we give a matching upper bound by providing an O(log A)-competitive strategy for simple rectilinear polygons, using the assumption that each edge of the polygon has to be fully visible from some scan point.
Relative Entropy and Statistics
Venue: arXiv cs.IT 2010
Year: 2010

Formalising the confrontation of opinions (models) to observations (data) is the task of Inferential Statistics. Information Theory provides us with a basic functional, the relative entropy (or Kullback-Leibler divergence), an asymmetrical measure of dissimilarity between the empirical and the theoretical distributions. The formal properties of the relative entropy turn out to be able to capture every aspect of Inferential Statistics, as illustrated here, for simplicity, on dices (= i.i.d. process with finitely many outcomes): refutability (strict or probabilistic): the asymmetry data / models; small deviations: rejecting a single hypothesis; competition between hypotheses and model selection; maximum likelihood: model inference and its limits; maximum entropy: reconstructing partially observed data; EM-algorithm; flow data and gravity modelling; determining the order of a Markov chain.
Energy Scaling Laws for Distributed Inference in Random Fusion Networks
Venue: arXiv cs.IT 2010
Year: 2010

The energy scaling laws of multihop data fusion networks for distributed inference are considered. The fusion network consists of randomly located sensors distributed i.i.d. according to a general spatial distribution in an expanding region. Among the class of data fusion schemes that enable optimal inference at the fusion center for Markov random field (MRF) hypotheses, the scheme with minimum average energy consumption is bounded below by average energy of fusion along the minimum spanning tree, and above by a suboptimal scheme, referred to as Data Fusion for Markov Random Fields (DFMRF). Scaling laws are derived for the optimal and suboptimal fusion policies. It is shown that the average asymptotic energy of the DFMRF scheme is finite for a class of MRF models.