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International Conference on parallel and distributed Systems (ICPADS)

作者： Wei Zhang Hangjun Zhou Yuxing Peng Sikun Li National Laboratory of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

Consistency and responsiveness are two important factors in providing the sense of reality in distributed Virtual Environment (DVE). However, it is not easy to optimize both aspects because of the trade-off between these two factors. As a result, most existing consistency maintenance methods ignored the responsiveness requirements, or just assumed a simple responsiveness requirement model which cannot meet the real need of DVE systems. In this paper, we first present a new responsiveness requirement model. The model can describe requirement satisfaction situation of each node. Base on this model, we propose a responsiveness requirement based consistency method. The method can adjust the utilization of time resource according to the requirements of different nodes and improve the overall responsiveness performance by at least 20%. Therefore, it provides a good support to increase the applicability of DVE systems.

关键词： Delay effects Virtual environment distributed processing computer science Games Distance learning Electronic commerce Safety Research and development Real time systems

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Anode-ALM: An Aggregation-Based Application Level Multicast for Media Streaming

Anode-ALM: An Aggregation-Based Application Level Multicast ...

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International Symposium on parallel Architectures, Algorithms and Networks (ISPAN)

作者： Feng Liu Yuxing Peng Xicheng Lu Parallel and Distributed Processing Laboratory School of Computer Science and Technology National University of Defense Technology Changsha China

Building application level multicast (ALM) for media streaming, we had better keep the invariability of source to-end delay (S2EDelay) of any node on the tree, so as to avoid delay jitter problem. In this paper, we proposed an aggregation-based ALM architecture, which aggregates the unstable nodes within a local area into a relative stable aggregation node Anode, and then builds tree by Anodes. Anode shields node's dynamicity inside and behaves as a stable one outside. To build the architecture, we first proposed an Anode structure by n-dimension anti-cube, and proposed a distributed algorithm to bind the logic view and physical view of an Anode dynamically by the differentiation and assimilation operations, which maintain the integrality of the logic view while the physical view changes dynamically. Experiment results indicate that our algorithm can keep the S2EDelay invariability of the built ALM tree effectively.

关键词： Streaming media Anodes Delay Stability Application software Jitter distributed algorithms Logic Internet Network topology

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A Two-Phase Mapping Method for parallel Applications Simulation

A Two-Phase Mapping Method for Parallel Applications Simulat...

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International Conference on Computational Intelligence and Software Engineering (CiSE)

作者： Jianbin Fang Chuanfu Xu Yonggang Che Yufen Weng Zhenghua Wang National Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China

Efficient mapping of logical processes to physical processes is one of key technologies to accelerate parallel performance simulation. Aiming at minimizing the communications between SMP nodes and between host physical processes, this paper presents a novel method named TPsmp-LP 3 M. It automatically extracts communication pattern of logical processes from trace and then generates a two-phase mapping from logical processes to SMP clusters. Experimental results show that TPsmp-LP 3 M can outperform the regular mapping method by up to 20.2%.

关键词： Computational modeling computer simulation Bandwidth Predictive models Discrete event simulation Concurrent computing parallel processing Application software Laboratories distributed processing

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Matrix Inversion on the Cell/B.E. Processor

Matrix Inversion on the Cell/B.E. Processor

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IEEE International Conference on High Performance Computing and Communications (HPCC)

作者： Shodai Yokoyama Kazuya Matsumoto Stanislav Sedukhin Distributed Parallel Processing Laboratory Graduate School of Computer Science and Engineering University of Aizu Japan

The problem of inverting matrices is one that occurs in some problems of practical importance. This paper introduces and evaluates the block algorithm for high performance matrix inversion on the Cell Broadband Engine (Cell/B.E.) processor. The Cell/B.E. is a heterogeneous multi-core processor on a single-chip jointly developed by Sony, Toshiba and IBM, which has a very high speed of the single precision floating-point arithmetic. The discussed matrix inversion algorithm is a combination of the block algebraic path problem algorithm and the well-known block matrix inversion algorithm based on the LU decomposition. For relatively big matrices, this combined block algorithm spends the most time in computing matrix-matrix multiplication of blocks and achieves 149.4 Gflop/s on Cell/B.E., when PPE and six SPEs of PlayStation3 are used, or 93.4% of the aggregated double (PPE) and single (SPEs) precision peak performance, which is 160.0 Gflop/s.

关键词： Matrix decomposition Partitioning algorithms Floating-point arithmetic Engines Multicore processing Microprocessors Reduced instruction set computing High performance computing parallel processing computer science

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Laser-driven inertial ion focusing

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Physical Review E 2009年第1期79卷 015401(R)-015401(R)页

作者： H. B. Zhuo Wei Yu M. Y. Yu H. Xu X. Wang B. F. Shen Z. M. Sheng J. Zhang National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Institute for Fusion Theory and Simulation Zhejiang University Hangzhou 310027 China Institute for Theoretical Physics I Ruhr University Bochum D-44780 Germany Department of Physics Jiaotong University Shanghai 200240 China

A Hohlraum-like configuration is proposed for realizing a simple compact source for neutrons. A laser pulse enters a tiny thin-shelled hollow-sphere target through a small opening and is self-consistently trapped in the cavity. The electrons in the inner shell-wall region are expelled by the light pressure. The resulting space-charge field compresses the local ions into a thin layer that becomes strongly heated. An inward expansion of ions into the shell cavity then occurs, resulting in the formation at the cavity center of a hot spot of ions at high density and temperature, similar to that in inertial electrostatic confinement.

关键词： laser fusion neutron sources particle beam focusing ELECTROSTATIC CONFINEMENT FUSION DEVICE

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An Irregular cutting based distributed mapping algorithm for DVE systems

An Irregular cutting based distributed mapping algorithm for...

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Pacific-Asia Workshop on Computational Intelligence and Industrial Application, PACIIA

作者： Wei Zhang Hangjun Zhou Yuxing Peng Sikun Li Min Xi National Laboratory of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China Department of Computer Science Xi'an Jiaotong University Xi'an China

distributed Virtual Environment (DVE) systems have become more and more important both in academic communities and the industries. To guarantee the load constrain, the physical world integrity and the virtual world integrity, the virtual environment should be divided into several parts and mapped to multiple servers, which are located in geographically different places. Many centralized algorithms based on regular cutting method are proposed to solve this problem. However, the dynamic property of clients and distributed property of the system make the existing algorithms unable to undertake it. In this paper, we propose a metric to measure the cutting quality and design a distributed mapping algorithm based on an irregular cutting. Simulation results show that our algorithm greatly decreases the costs of DVE systems for migration of clients and effectively improves the satisfaction degree of users.

关键词： Defense industry Virtual environment computer industry computer science Algorithm design and analysis Delay Partitioning algorithms Industrial training Computational intelligence Application software

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SCQR - A P2P Query Routing Algorithm Based on Semantic Cluster

SCQR - A P2P Query Routing Algorithm Based on Semantic Clust...

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International Symposium on Intelligent Ubiquitous Computing and Education

作者： Shiyao Jin Gui-Ming Zhu School of Computer Science National University of Defense Technology Changsha China National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

The low efficiency and uncertainty routing is correct is a problem for resource location of an unstructured p2p network. It is hard to achieve high query hit with small cost and low latency for such kind of network. In this paper, we present a p2p query routing algorithm which is based on semantic cluster (SCQR). SCQR makes nodes clustered according to their semantic, and each cluster elects a super-node as cluster computing node which is responsible for computing cluster semantic and establishing links with all neighbor cluster computing nodes. Query is routed among cluster computing nodes. SCQR achieves high query hit with small routing latency and query cost in both analytical theoretical and experimental studies.

关键词： Query processing Clustering algorithms Peer to peer computing Routing Delay Costs computer networks Frequency Floods Intelligent networks

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An Optimal Mapping Algorithm Based on Balanced Load Cutting for DVE Systems

An Optimal Mapping Algorithm Based on Balanced Load Cutting ...

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International Symposium on Intelligent Information Technology Application, IITA

作者： Wei Zhang Min Xi Hangjun Zhou Yuxing Peng Sikun Li National Laboratory for Parallel and Distributed Processing National University of Defense Technology ChangSha China Department of Computer Science Xi'an Jiaotong University Xi'an China

In distributed virtual environment (DVE) systems, a distributed server infrastructure is often used to reduce the latency between servers and clients. Under this infrastructure, mapping clients to proper servers is one of the key issues for improving the interactivity and overall performance. Most traditional methods of mapping the clients to servers only consider the load balancing problem. However, there are two other important aspects that should be involved: the physical world integrity and the virtual world integrity. In this work, we propose a novel mapping algorithm which takes care of all three aspects at the same time. The algorithm converts the mapping problem into cutting stage and matching stage to get optimal result with polynomial complexity. The experimental results show that our algorithm improves the overall performance of DVE systems significantly.

关键词： Delay Network servers computer science Virtual environment Load management Polynomials Quality of service Information technology Application software distributed processing

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Scalable unbiased sampling method based on multi-peer adaptive random walk

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Ruan Jian Xue Bao/Journal of Software 2009年第3期20卷 630-643页

作者： Fu, Yong-Quan Wang, Yi-Jie Zhou, Jing National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China Staff Room of Computer Command Academy of the Corps of Engineers Xuzhou 221000 China

To deal with the scalable and fast unbiased sampling problems in unstructured P2P systems, a sampling method based on multi-peer adaptive random walk (SMARW) is proposed. In the method, based on the multi-peer random walk process, a set of provisional peers are selected as agents which start the sampling processes, by which the sampling process is speeded up with receiving a set of tunable number samples each time;Meanwhile, after receiving new samples earlier agents are replaced with these new samples which repeat the sampling process. With this simple replacement, it can be guaranteed with high probability that the system can reach the optimal load balance;furthermore, SMARW adopts an adaptive distributed random walk adjustment process to increase the convergence rate of the sampling process. A detailed theorical analysis and performance evaluation confirm that SMARW has a high level of unbiased sampling and near-optimal load balancing capability. © by Institute of Software, the Chinese Academy of sciences. All rights reserved.

关键词： Peer to peer networks

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An example-based decoder for spoken language machine translation 6

An example-based decoder for spoken language machine transla...

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6th SIGHAN Workshop on Chinese Language processing, SIGHAN 2008

作者： Li, Zhou-Jun Chao, Wen-Han Chen, Yue-Xin National Laboratory for Parallel and Distributed Processing Changsha China School of Computer Science and Engineering Beihang University China

In this paper, we propose an example-based decoder for a statistical machine translation (SMT) system, which is used for spoken language machine translation. In this way, it will help to solve the re-ordering problem and other problems for spoken language MT, such as lots of omissions, idioms etc. Through experiments, we show that this approach obtains improvements over the baseline on a Chinese-English spoken language translation task. © IJCNLP 2008. All rights reserved.

关键词： Machine translation

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