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the direct-error-compensation method of measuring the error of a six-freedom-degree parallel mechanism CMM

JOURNAL OF MATERIALS processing TECHNOLOGY 2002年第1-3期129卷 574-578页

作者： Meng, Z Che, RS Huang, QC Yu, ZJ Harbin Inst Technol Discipline Instrumentat Sci & Technol Harbin 150001 Peoples R China

A six-freedom-degree parallel mechanism CMM is designed. It has some characteristic, such as good system rigidity, rapid motion velocity, not-accumulative error, and a flexible end position stance. the errors influencing the probe position stance are analysed: they are original error of the machine, the process error for measuring, and other stochastic errors. Amongst them, the original error of the machine is the main factor causing probe error. Probe error influences directly the measuring precision of the six-freedom-degree parallel mechanism CMM. A coordinate system for analyzing the position is set-up and its position reverse solution model is obtained. Based on the position reverse solution model and according to matrix complete differential-coefficient theory, the relationship between the original machine error and the probe position stance error is deducted. and the error model is built. Creating a program in the Matlab language to calculate the error model, the position stance error of the probe is obtained under the condition of determinate machine error. Using this result to correct the probe position stance, namely the direct-error-compensation method, can clearly improve the measurement precision. the theory and flow chart of this method are introduced in the paper. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： coordinate measuring machine (CMM) six-freedom-degree parallel mechanism CMM error models position-stance error direct-error-compensation method

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the direct-error-compensation method of measuring the error of a six-freedom-degree parallel mechanism CMM

The direct-error-compensation method of measuring the error ...

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10th international Manufacturing conference in China (IMCC 2002)

作者： Meng, Z Che, RS Huang, QC Yu, ZJ Harbin Inst Technol Discipline Instrumentat Sci & Technol Harbin 150001 Peoples R China

关键词： coordinate measuring machine (CMM) six-freedom-degree parallel mechanism CMM error models position-stance error direct-error-compensation method

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the CDAG: a data structure for automatic parallelization for a multithreaded architecture

The CDAG: a data structure for automatic parallelization for...

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Euromicro conference on parallel, Distributed and Network-Based processing

作者： B. Klauer F. Eschmann R. Moore K. Waldschmidt Technical Computer Sc. Dep Johann Wolfgang Goethe-University of Frankfurt Frankfurt Germany

ISBN: (纸本)0769514448

Despite the explosive new interest in distributed computing, bringing software-particularly legacy software-to parallel platforms remains a daunting task. the self distributing associative architecture (SDAARC) takes a two-fold approach to this problem. Seemingly sequential programs are first translated into a population of migratory threads and containers by the compiler, and then allowed to migrate to minimize communication while maximizing parallelism by a run time environment. However previous compilers for multithreaded architectures such as SDAARC did not permit the full range of control flow complexity found in programming languages such as C. thus, we propose a new data structure, and present algorithms for its construction, which extends the familiar concepts of control flow and data flow graphs to conveniently represent the activities required of an automatically generated thread.

关键词： Data structures Yarn Program processors Automatic generation control Explosives Distributed computing Computer architecture Containers parallel processing Communication system control

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Receptive fields within the combinatorial pyramid framework 10th

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10th international conference on Discrete Geometry for Computer Imagery, DGCI 2002

作者： Brun, Luc Kropatsch, Walter G. Université de Reims France Institute for Computer-aided Automation Pattern Recognition and Image Processing Group Vienna Univ. of Technology Austria

ISBN: (纸本)3540433805

A hierarchical structure is a stack of successively reduced image representations. Each basic element of a hierarchical structure is the father of a set of elements in the level below. the transitive closure of this father-child relationship associates to each element of the hierarchy a set of basic elements in the base level image representation. Such a set, called a receptive field, defines the embedding of one element of the hierarchy on the original image. Using the father-child relationship, global properties of a receptive field may be computed in O(log(m)) parallel processing steps where m is the diameter of the receptive field. Combinatorial pyramids are defined as a stack of successively reduced combinatorial maps, each combinatorial map being defined by two permutations acting on a set of half edges named darts. the basic element of a combinatorial pyramid is thus the dart. this paper defines the receptive field of each dart within a combinatorial pyramid and study the main properties of these sets. © Springer-Verlag Berlin Heidelberg 2002.

关键词： Image representation

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Recursive filters using systolic architectures and switched capacitor techniques

Recursive filters using systolic architectures and switched ...

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IEEE international conference on Electronics, Circuits and Systems (ICECS)

作者： D. Chikouche R.E. Bekka A. Boucenna Département d Electronique Faculté des Sciences de IIngénieur Université de Satif Setif Algeria

In this paper, the discrete state space recursive filters are implemented in the form of parallel array processors. the state space description permits the straightforward application of systolic architectures to realize recursive filters of 1D and 2D types. We show that the recursivity inherent to the filtering algorithm introduces a latency proportional to the filter order. Moreover, we show that the use of the CTP decomposition technique together with the cylindrical-type structures reduces significantly this latency and improves the computation throughput of these arrays. the processing cells of the systolic array are designed via switched-capacitor techniques.

关键词： Filters Capacitors State-space methods Computer architecture throughput Equations Filtering algorithms Delay Systolic arrays Process design

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Improving SMT performance scheduling processes

Improving SMT performance scheduling processes

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Euromicro conference on parallel, Distributed and Network-Based processing

作者： R. Goncalves P. Navaux Departamento de Informatica Universidade Estadual de Maringa Maringa PR Brazil Universidade Federal do Rio Grande do Sul Instituto de Informatica Porto Alegre RS Brazil

ISBN: (纸本)0769514448

Nowadays, SMT (simultaneous multithreaded) architectures use aggressive techniques to execute instructions from different threads on shared resources simultaneously. SEMPRE (Superscalar architEcture with Multiple PRocesses in Execution) is a type of SMT architecture which was proposed to schedule and execute processes simultaneously. the waste of time on both process scheduling and context switching is minimal, providing high performance during the execution of applications. the SEMPRE architecture was analyzed and evaluated using execution-driven simulations of the SPEC benchmark suite. the simulations showed that process scheduling by hardware can provide reasonable performance over process scheduling by the operating system on equivalent SMT architectures, with little extra hardware. this higher performance is achieved because the hardware makes better use of the process time-slice. the performance of SEMPRE is always higher than the performance of traditional SMT, achieving more than 21% in some cases.

关键词： Surface-mount technology Yarn parallel processing Operating systems Hardware Switches Read only memory Process control Computer architecture Pipelines

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A parallel search genetic algorithm based on multiple peak values and multiple rules

A parallel search genetic algorithm based on multiple peak v...

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10th international Manufacturing conference in China (IMCC 2002)

作者： Guo, LX Zhao, MY Chinese Acad Sci Shenyang Inst Automat Shenyang 110016 Peoples R China

In this paper, Hamming distance is used to control individual difference in the process of creating an original population, and a peak-depot is established to preserve information of different peak-points. Some new methods are also put forward to improve the optimization performance of a genetic algorithm (GA), such as the point-cast method and the neighborhood search strategy around peak-points. the methods, are used to deal with genetic operation as well as cross-over and mutation, in order to obtain a global optimum solution and avoid the GAs premature convergence. By means of many control rules and a peak-depot, the new algorithm carries out an optimum search surrounding several peak-points. Along with the evolution of individuals of the population, the fitness of peak-points of peak-depot increases continually, and a global optimum solution can be obtained. the new algorithm searches around several peak-points, which increases the probability of obtaining the best global optimum solution. the results of some examples to test the modified GA indicate that what has been done makes the modified genetic algorithm effective in solving both linear optimization problems and non-linear optimization problems with restrictive functions. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： genetic algorithm peak-depot individual difference control point-cast method multi-peak search

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Fast software implementation of MPEG advanced audio encoder

Fast software implementation of MPEG advanced audio encoder

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international conference on Digital Signal processing (DSP)

作者： I. Dimkoviae D. Milovanoviae Z. Bojkoviae PsyTEL Research Belgrade Serbia Faculty of Elcclrical Engineering Belgrade Serbia

An optimized software implementation of a high quality MPEG AAC-LC (low complexity) audio encoder is presented in this paper. the standard reference encoder is improved by utilizing several algorithmic optimizations (fast psycho-acoustic model, new tonality estimation, new time domain block switching, optimized quantizer and Huffman coder) and very careful code optimizations for PC CPU architectures with SIMD (single-instruction-multiple-data) instruction set. the psychoacoustic model used the MDCT filterbank for energy estimation and peak detection as a measure of tonality. Block size decision is based on local perceptual entropies as well as LPC analysis of the time signal. Algorithmic optimizations in the quantizer include loop control module modification and optimized Huffman search. Code optimization is based on parallel processing by replacing vector algebra and math junctions with their optimized equivalents with Intel/sup /spl reg// Signal processing Library (SPL). the implemented codec outperforms consumer MP3 encoders at 30% less bitrate at the same time achieving encoding times several times faster than real-time.

关键词： Signal processing algorithms Psychoacoustic models Software quality Code standards Psychology Filter bank Energy measurement Entropy Linear predictive coding Signal analysis

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Mobility and mobility management: a conceptual framework

Mobility and mobility management: a conceptual framework

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IEEE international conference on Networks

作者： Jun-Zhao Sun J. Sauvola MediaTeam Machine Vision and Media Processing Unit Infotech Oulu University of Oulu Oulu Finland

ISBN: (纸本)0780375335

the tremendous demands from the social market are pushing the development of mobile communications faster than ever before, leading to the emergence of many new techniques. Within those techniques, mobility management has widely been recognized as one of the most important problems for seamless access to wireless networks and services. this paper proposes a conceptual framework for mobility and mobility management, with the emphasis on the key research issues involved in the effort to design graceful mobility management schemes. the effects of mobility on both the architectures and protocols of networks and communications are presented. Diversity of the future mobile communication systems introduces new challenges, which lead to the definitions of mobility on various levels according to different granularities. Mobility management is defined as two complementary operations, i.e. location management and handoff management. the paper also describes mobility management issues at the network layer. the processing stages of the two operations are introduced, together with the analyses of key research issues and possible solutions. Finally, we discuss issues concerning the performance evaluation of mobility management schemes.

关键词： Mobile radio mobility management Mobile communication Wireless networks Access protocols Mobile computing 3G mobile communication Roaming Sun Machine vision Bandwidth

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A geographically pinned QoS routing scheme for mobile ad hoc networks

A geographically pinned QoS routing scheme for mobile ad hoc...

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IEEE international conference on Networks

作者： Chi-Hsiang Yeh Department of Electrical and Computer Engineering Queen's University Kingston ONT Canada

ISBN: (纸本)0780375335

In this paper, we advocate that quality of service (QoS) routing protocols should use routes that are weaved and/or geographically pinned. this leads to a new paradigm for QoS routing called geographically pinned QoS routing (GPQR). Based on GPQR, we propose the embedded QoS routing (EQR) scheme for scalable routing with support for Differentiated Service and QoS guarantees in mobile ad hoc networks (MANET) and ad hoc cellular networks (ACENET). Due to the QoS routing disciplines proposed for EQR, the philosophy for selecting and provisioning QoS routes in EQR is fundamentally changed. Moreover, EQR combines several important advantages of localized routing and table-driven routing, including scalability and capability for wireless traffic engineering.

关键词： Mobile ad hoc networks Quality of service parallel processing Routing protocols Scalability throughput Concurrent computing Embedded computing Telecommunication traffic Power engineering and energy

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