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A parallel SIMULATED ANNEALING ALGORITHM

parallel COMPUTING 1993年第8期19卷 859-872页

作者： BOISSIN, N LUTTON, JL France Telecom Centre National d'Etudes des T&eacute l&eacute communications PAA/ATR/ORI 38 rue du G&eacute n&eacute ral Leclerc 92131 Issy Les Moulineaux France

In this paper we present a generalization of the sequential simulated annealing algorithm for combinatorial optimization problems. By performing a parallel study of the current solution neighbourhood we obtain an algorithm that can be very efficiently implemented on a massively parallel computer. We test the convergence and the quality of our algorithm by comparing it to the sequential algorithm for two classical problems: the minimization of an unconstrained 0-1 quadratic function and the quadratic sum assignment problem.

关键词： COMBINATORIAL OPTIMIZATION SIMULATED ANNEALING parallel implementations

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parallel FETI algorithms for mortars

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APPLIED NUMERICAL MATHEMATICS 2005年第2期54卷 266-279页

作者： Stefanica, D CUNY Bernard M Baruch Coll New York NY 10010 USA MIT Cambridge MA 02139 USA

We propose a new version of the FETI algorithm for mortar discretizations based on generalized coupling conditions across the interface. The new algorithm preserves the parallelization properties of, and has the same scalability properties as, the FETI method for continuous finite elements. We compare the numerical performance of the new algorithm with that of other FETI methods for mortars. When mortar conditions are required only on a small part of the interface, while continuity is required elsewhere, we show that the extra storage and extra computational effort required by the parallel algorithm is minimal. (c) 2004 IMACS. Published by Elsevier B.V. All rights reserved.

关键词： FETI method mortar finite elements parallel implementations

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FOURIER MATRIX DECOMPOSITION METHODS FOR THE LEAST-SQUARES SOLUTION OF SINGULAR NEUMANN AND PERIODIC HERMITE BICUBIC COLLOCATION PROBLEMS

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SIAM JOURNAL ON SCIENTIFIC COMPUTING 1995年第2期16卷 431-451页

作者： BIALECKI, B REMINGTON, KA OAK RIDGE NATL LAB OAK RIDGETN 37831

The use of orthogonal spline collocation with piecewise Hermite bicubics is examined for the solution of Poisson's equation on a rectangle subject to either pure Neumann or pure periodic boundary conditions. Emphasis is placed on finding a least squares solution of these singular collocation problems. The technique of matrix decomposition is applied and explicit formulas for the requisite eigensystems corresponding to two-point Neumann and periodic collocation boundary value problems are presented. The resulting algorithms use fast Fourier transforms for efficiency and are highly parallel in nature. On an N x N partition, a fourth order accurate least squares solution is computed at a cost of O(N-2 log N) operations. The results of numerical experiments are provided that demonstrate that the implementations compare very favorably with recent fourth order accurate finite difference and finite element Galerkin codes.

关键词： POISSONS EQUATION NEUMANN AND PERIODIC BOUNDARY CONDITIONS PIECEWISE HERMITE BICUBICS ORTHOGONAL SPLINE COLLOCATION FAST DIRECT SOLVERS LEAST SQUARES SOLUTIONS MATRIX DECOMPOSITION ALGORITHMS FAST FOURIER TRANSFORMS parallel implementations

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Shuffled Decoding of Serial Concatenated Convolutional Codes 11

Shuffled Decoding of Serial Concatenated Convolutional Codes

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11th International Symposium on Topics in Coding (ISTC)

作者： Bourenane, Aomar Arzel, Matthieu Guilloud, Frederic Thomas, Alain Space & Commun Lab Safran Data Syst Les Ulis France IMT Atlantique Lab STICC UMR CNRS 6285 F-29238 Brest France

ISBN: (纸本)9781665409438

Shuffled decoding enables to accelerate the extrinsic information exchange during iterative decoding of concatenated codes. It has already been applied to parallel convolutional codes or low-density parity-check codes. In this article, we propose to apply shuffled decoding to serial concatenation convolutional codes. We take advantage of their systematic encoding to propose an efficient shuffled decoding scheme. Compared to a standard iterative decoding scheme, the convergence of our shuffled implementation is obtained within fewer iterations, each one requiring also less time to be completed. This convergence acceleration yields doubling the throughput. We finally show that doubling the throughput comes at a lower cost than doubling the hardware resources, making this shuffled scheme efficient in term of implementation. For instance, the memory usage is 29% more efficient thanks to our proposal than a baseline scheme, which significantly reduces the power consumption of hardware decoders.

关键词： Serial Concatenated Convolutional Codes (SCCC) iterative decoding shuffled decoding parallel implementations

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An Imperialistic Strategy Approach to Continuous Global Optimization Problem 16

An Imperialistic Strategy Approach to Continuous Global Opti...

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16th International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC)

作者： Anescu, George Univ Politehn Bucuresti Power Plant Engn Fac Bucharest 060042 Romania

ISBN: (纸本)9781479984480

The paper is introducing the principles of a new global optimization strategy, Imperialistic Strategy (IS), applied to the Continuous Global Optimization Problem (CGOP). Inspired from existing multi-population strategies, like the Island Model (IM) approaches to parallel Evolutionary Algorithms (EA) and the Imperialistic Competitive Algorithm (ICA), the proposed IS method is considered an optimization strategy for the reason that it can integrate other well-known optimization methods, which in the context are regarded as sub-methods (although in other contexts they are prominent global optimization methods). Four optimization methods were implemented and tested in the roles of sub-methods: Genetic Algorithm (GA) (a floating-point representation variant), Differential Evolution (DE), Quantum Particle Swarm Optimization (QPSO) and Artificial Bee Colony (ABC). The optimization performances of the proposed optimization methods were compared on a test bed of 9 known multimodal optimization problems by applying an appropriate testing methodology. The obtained increased success rates of IS multi-population variants compared to the success rates of the optimization sub-methods run separately, combined with the increased computing efficiencies possible to be perceived for parallel and distributed implementations, demonstrated that IS is a promising approach to CGOP.

关键词： genetic algorithms parallel algorithms quantum computing ABC CGOP DE EA GA ICA IM IS multipopulation variants QPSO artificial bee colony continuous global optimization problem differential evolution distributed implementations floating-point representation variant genetic algorithm imperialistic competitive algorithm imperialistic strategy approach island model multimodal optimization problems multipopulation strategies parallel evolutionary algorithms parallel implementations quantum particle swarm optimization Biological cells Genetic algorithms Linear programming Optimization Sociology Statistics Vectors Artificial Bee Colony Continuous Global Optimization Problem Differential Evolution Genetic Algorithm IS Imperialistic Competitive Algorithm Imperialistic Strategy Island Model Quantum Particle Swarm Optimization Genetic Algorithm (GA) MT activity based costing Independent component analysis islet cell antibody Instant messaging Particle swarm optimization Gallium cytology Sociology parallel algorithms quantum computing Policies and plans bee colonies linear programming

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Clusters versus FPGAs for Spectral Mixture Analysis-Based Lossy Hyperspectral Data Compression

Clusters versus FPGAs for Spectral Mixture Analysis-Based Lo...

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Conference on Satellite Data Compression, Communications and Archiving IV

作者： Plaza, Antonio J. Univ Extremadura Dept Technol Comp & Commun E-10071 Caceres Spain

ISBN: (纸本)9780819473042

The increasing number of airborne and satellite platforms that incorporate hyperspectral imaging spectrometers has soon created the need for efficient storage, transmission and data compression methodologies. In particular, hyperspectral data compression is expected to play a crucial role in many remote sensing applications. Many efforts have been devoted to designing and developing lossless and lossy algorithms for hyperspectral imagery. However, most available lossy compression approaches have largely overlooked the impact of mixed pixels and subpixel targets, which can be accurately modeled and uncovered by resorting to the wealth of spectral information provided by hyperspectral image data. In this paper, we develop a simple lossy compression technique which relies on the concept of spectral unmixing, one of the most popular approaches to deal with mixed pixels and subpixel targets in hyperspectral analysis. The proposed method uses a two-stage approach in which the purest spectral signatures (also called endmembers) are first extracted from the input data, and then used to express mixed pixels as linear combinations of endmembers. Analytical and experimental results are presented in the context of a real application, using hyperspectral data collected by NASA's Jet Propulsion Laboratory over the World Trade Center area in New York City, right after the terrorist attacks of September 11th. These data are used in this work to evaluate the impact of compression using different methods on spectral signature quality for accurate detection of hot spot fires. Two parallel implementations are developed for the proposed lossy compression algorithm: a multiprocessor implementation tested on Thunderhead, a massively parallel Beowulf cluster at NASA's Goddard Space Flight Center, and a hardware implementation developed on a Xilinx Virtex-II FPGA device. Combined, these parts offer a thoughtful perspective on the potential and emerging challenges of incorporating parallel d

关键词： Hyperspectral imaging data compression parallel implementations clusters of computers field programmable gate arrays (FPGAs)

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Techniques of linear programming based on the theory of convex cones

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Optimization 1989年第6期20卷 761-777页

作者： D’Alessandro, P. Mora, Manuel Dalla De Santis, Elena University of I’A quila Department of Electrical Engineering Italy

The convex cones approach to linear programming is illustrated. Two methods are introduced. The first, called primal, is based on a tangeney condition for nonnegative orthant and an affine set. The second, called dual, uses the extreme rays of a pointed polyhedral cone, given by the intersection of the nonnegative orthant with a subspace, to compute the maximum and than proceeds in the same way as the primal to derive the solution. A complete theory for the extreme rays of any cone of this form is given. Another highlight of the paper is the theory of the strictly tangent relaxation, which is independent of the particular method used, and allows the reduction of the problem to a minimal form. A numerical example is included to give a practical feeling of the dual method. Finally features of the methods, like the possibility of highly parallel implementations, open problems and perspectives are discussed. © 1989, Taylor & Francis Group, LLC. All rights reserved.

关键词： Extreme rays parallel implementations Polyhedral cones Reduction of dimension of linear programming problems Solution of linear programming problems

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Performance analysis and parallel implementation of dedicated hash functions 1

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International Conference on the Theory and Applications of Cryptographic Techniques

作者： Nakajima, J Matsui, M Mitsubishi Electr Corp Kamakura Kanagawa 2478501 Japan

ISBN: (数字)9783540460350

ISBN: (纸本)3540435530

This paper shows an extensive software performance analysis of dedicated hash functions, particularly concentrating on Pentium III, which is a current dominant processor. The targeted hash functions are MD5, RIPEMD-128 -160, SHA-1-256 -512 and Whirlpool, which fully cover currently used and future promising hashing algorithms. We try to optimize hashing speed not only by carefully arranging pipeline scheduling but also by processing two or even three message blocks in parallel using MMX registers for 32-bit oriented hash functions. Moreover we thoroughly utilize 64-bit MMX instructions for maximizing performance of 64-bit oriented hash functions, SHA-512 and Whirlpool. To our best knowledge, this paper gives the first detailed measured performance analysis of SHA-256, SHA-512 and Whirlpool.

关键词： dedicated hash functions parallel implementations Pentium III

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Measuring Efficiency of Ant Colony Communities 10th

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10th International on Conference Multimedia and Network Information Systems (MISSI)

作者： Sieminski, Andrzej Wroclaw Univ Sci & Technol Fac Comp Sci & Management Wroclaw Poland

ISBN: (纸本)9783319439822;9783319439815

The paper presents a study on the efficiency measures of the Ant Colony Communities (ACC). The ACC is an approach to parallelize the Ant Colony Optimization algorithm (ACO). An ACC is made up of a Community Server that coordinates the work of a set Ant Colony clients. Each client implements a classical ACO algorithm. The individual colonies work in an asynchronous manner processing data sent by server and sending back the obtained results. There are many possible locations for the clients: the same computer as the server, computers of a local or wide area network. The paper presents a detailed description of concept the ACC and reports the study of the efficiency of the such Communities. The efficiency is measured by their power (the amount of data processed in a given period of time) and scalability-the efficiency of adding colony clients on the Community. The paper contains also the taxonomy of parallel implementations of the Ant Colony.

关键词： Ant colony optimization Travelling salesman problem parallel implementations Sockets Task complexity ACC power ACC scalability

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parallel FETI algorithms for mortars

Parallel FETI algorithms for mortars

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6th International Symposium on Iterative Methods in Scientific Computing

作者： Stefanica, D CUNY Bernard M Baruch Coll New York NY 10010 USA MIT Cambridge MA 02139 USA

关键词： FETI method mortar finite elements parallel implementations

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