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15th International Conference on parallel and distributed Systems, ICPADS '09

作者： Fu, Yongquan Wang, Yijie National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology China

ISBN: (纸本)9780769539003

Predicting network latencies between Internet hosts can efficiently support large-scale Internet applications, e.g., file sharing service and the overlay construction. Several study use the Hyperbolic space to model the Internet densecore and many-tendril structure. However, existing Hyperbolic space based embedding approaches are not designed for accurate latency estimation in the distributed context. We present HyperSpring, which estimates latency by modelling a mass spring system in the Hyperbolic similar with Vivaldi. HyperSpring adopts coordinate initialization to speed up the convergence of coordinate computation, uses multiple-round symmetric updates to escape from bad local minima, and stabilizes coordinates by compensating RTT measurements to reduce the coordinate drifts. Evaluation results based on a network trace of 226 PlanetLab nodes indicate that, compared to Euclidean-space based Vivaldi, HyperSpring provides performance improvements for most nodes, and incurs slightly higher distortions for a small number of nodes. © 2009 IEEE.

关键词： Hyperbolic space Latency estimation Mass spring field

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iRank: Supporting proximity ranking for peer-to-peer applications

iRank: Supporting proximity ranking for peer-to-peer applica...

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15th International Conference on parallel and distributed Systems, ICPADS '09

作者： Fu, Yongquan Wang, Yijie National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology China

ISBN: (纸本)9780769539003

Proximity ranking according to end-to-end network distances (e.g., Round-Trip Time, RTT) can reveal detailed proximity information, which is important in network management and performance diagnosis in distributed systems. However, to the best of our knowledge, there has been no similar work on this subject in the P2P computing field. We present a distributed rating method iRank, that enables proximity rankings by providing discrete ratings in a distributed manner. It formulates the proximity ranking as a rating problem that faithfully captures the proximity based on noisy distance measurements scalably and practically. The primary challenge in inferring proximity rankings is enforcing distributed ratings with complex rating policies. Our solution is based on reconstructing ratings by decomposing a centralized rating method Maximum Margin Matrix Factorization (MMMF) into independent sub-problems, that can be efficiently solved in a decentralized manner. By relaxing the dependence on infrastructure nodes that are a single point of failure and limit scalability, iRank can gracefully handle network churns. Through real network latency data sets, we demonstrate that iRank can predict ratings with low distortion, which are smaller than 20 percentage worse than the centralized method, in the context of synthetic complex rating policies. © 2009 IEEE.

关键词： Complex networks

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Anadem: A hybrid overlay network for content-based data distribution

Anadem: A hybrid overlay network for content-based data dist...

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15th International Conference on parallel and distributed Systems, ICPADS '09

作者： Zheng, Zhong Wang, Yi-Jie National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China

ISBN: (纸本)9780769539003

As an infrastructure for data distribution, overlay networks have to feature efficient routing and adequate robustness to achieve fast and accurate data distribution in the environment with node churn. Considering that the existing overlay networks mostly focus on single optimization objective and fail to ensure routing efficiency and robustness simultaneously, a hybrid overlay network for content-based data distribution - Anadem is proposed in this paper. Anadem achieves a better compromise between routing efficiency and robustness by combining the intercluster multiple structured topologies with the intra-cluster unstructured topologies. Anadem also provides mechanisms for dynamic concurrent cluster creation, cluster departure and load balance to make data distribution more adaptive to the dynamic network environment. Experimental results reveal that compared with existing overlay networks, Anadem can support fast and accurate content-based data distribution even when large amount of nodes fail in the system. © 2009 IEEE.

关键词： Overlay networks

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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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2009 International Conference on Computational Intelligence and Software Engineering, CiSE 2009

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

ISBN: (纸本)9781424445073

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-LP3M. 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-LP3M can outperform the regular mapping method by up to 20.2%. ©2009 IEEE.

关键词： Mapping

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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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2009 2nd Asia-Pacific Conference on Computational Intelligence and Industrial Applications, PACIIA 2009

作者： Zhang, Wei Zhou, Hangjun Peng, Yuxing Li, Sikun Xi, Min National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Department of Computer Science Xi'an Jiaotong University Xi'an 710049 China

ISBN: (纸本)9781424446070

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. ©2009 IEEE.

关键词： Virtual reality

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Quasimonoenergetic Proton Bunch Generation by Dual-Peaked Electrostatic-Field Acceleration in Foils Irradiated by an Intense Linearly Polarized Laser

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Physical Review Letters 2010年第6期105卷 065003-065003页

作者： H. B. Zhuo (卓红斌) Z. L. Chen (陈正林) W. Yu (余玮) Z. M. Sheng (盛政明) M. Y. Yu (郁明阳) Z. Jin (金展) R. Kodama (兒玉了祐) Graduate School of Engineering Osaka University 2-1 Yamada-oka Suita Osaka 565-0871 Japan National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 People’s Republic of China Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 People’s Republic of China Department of Physics Shanghai Jiao Tong University Shanghai 200240 People’s Republic of China Beijing National Laboratory for Condensed Matter Physics Institute of Physics CAS Beijing 100080 People’s Republic of China Institute for Fusion Theory and Simulation Zhejiang University Hangzhou 310027 People’s Republic of China Institute for Theoretical Physics I Ruhr University Bochum D-44780 Germany Institute of Laser Engineering Osaka University 2-6 Yamada-oka Suita Osaka 565-0871 Japan

It is found that stable proton acceleration from a thin foil irradiated by a linearly polarized ultraintense laser can be realized for appropriate foil thickness and laser intensity. A dual-peaked electrostatic field, originating from the oscillating and nonoscillating components of the laser ponderomotive force, is formed around the foil surfaces. This field combines radiation-pressure acceleration and target normal sheath acceleration to produce a single quasimonoenergetic ion bunch. A criterion for this mechanism to be operative is obtained and verified by two-dimensional particle-in-cell simulation. At a laser intensity of ∼5.5×1022 W/cm2, quasimonoenergetic GeV proton bunches are obtained with ∼100 MeV energy spread, less than 4° spatial divergence, and ∼50% energy conversion efficiency from the laser.

关键词： Germanium compounds

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Fast query over encrypted data based on B+ tree

Fast query over encrypted data based on B+ tree

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2009 International Conference on Apperceiving Computing and Intelligence Analysis, ICACIA 2009

作者： Wang, Zheng-Fei Tang, Ai-Guo Wang, Wei Department of Computer Hunan Business College Changsha 410205 China National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China School of Computer Science Fudan University Shanghai 200433 China

ISBN: (纸本)9781424452040

There are a lot of important and sensitive data in databases, which need to be protected from attacks. To secure the data, Cryptography support is an effective mechanism. However, a tradeoff must be made between the performance and the security because encryption and decryption greatly degrade the query performance. In this paper, a framework is proposed that can quickly implement query over encrypted data based on B+ tree. When data are stored in the form of cipher, it not only stores the encrypted data themselves, but also creates a B+ tree index for the data before encrypting them. When querying the encrypted data, firstly, it locates the encrypted records related to the querying predicate based on the B+ tree index;secondly, it decrypts the encrypted records to accomplish the results. Meanwhile, it must encrypt the B+ tree itself to protect it from leaking confidential information. According to the structure of the B+ tree, it encrypts each node of the B+ tree separately. The results of experiments show that the query performance over the encrypted data decreases about 20 percent compared with the plaintext query performance, and validate the functionality and usability of our approach. ©2009 IEEE.

关键词： Cryptography

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iRank: Supporting Proximity Ranking for Peer-to-Peer Applications

iRank: Supporting Proximity Ranking for Peer-to-Peer Applica...

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International Conference on parallel and distributed Systems (ICPADS)

作者： Yongquan Fu Yijie Wang National Key Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology China

关键词： Peer to peer computing distributed computing computer networks Network servers Application software Laboratories distributed processing Concurrent computing computer network management Conference management

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HyperSpring: Accurate and Stable Latency Estimation in the Hyperbolic Space

HyperSpring: Accurate and Stable Latency Estimation in the H...

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International Conference on parallel and distributed Systems (ICPADS)

作者： Yongquan Fu Yijie Wang National Key Laboratory of Parallel and Distributed Processing School of Computer National University of Defense Technology China

Predicting network latencies between Internet hosts can efficiently support large-scale Internet applications, e.g., file sharing service and the overlay construction. Several study use the hyperbolic space to model the Internet dense-core and many-tendril structure. However, existing hyperbolic space based embedding approaches are not designed for accurate latency estimation in the distributed context. We present HyperSpring, which estimates latency by modelling a mass spring system in the hyperbolic similar with Vivaldi. HyperSpring adopts coordinate initialization to speed up the convergence of coordinate computation, uses multiple-round symmetric updates to escape from bad local minima, and stabilizes coordinates by compensating RTT measurements to reduce the coordinate drifts. Evaluation results based on a network trace of 226 PlanetLab nodes indicate that, compared to Euclidean-space based Vivaldi, hyperspring provides performance improvements for most nodes, and incurs slightly higher distortions for a small number of nodes.

关键词： Delay IP networks Web and internet services Large-scale systems Peer to peer computing Springs Convergence Coordinate measuring machines Distortion measurement Extraterrestrial measurements

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Optimization techniques of on-chip memory system based on UltraSPARC architecture

Optimization techniques of on-chip memory system based on Ul...

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Asia Pacific Conference on Postgraduate Research in Microelectronics & Electronics (PrimeAsia)

作者： Anwen Huang Jun Gao Chaochao Feng Minxuan Zhang Key Laboratory of Science and Technology of National Defense of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

It is of great significance to optimize the design of on-chip memory system for improving the performance of multi-core processor. This paper describes the organization of on-chip memory hierarchy in UltraSPARC T2, analyzes the procedure of dealing with the memory access request from multi-core processor in detail. To get the basic parameters of timing characteristic and area consumption, the primary element of on-chip memory system is simulated by ModelSim and synthesized by Synopsys Design Complier with 90 nm standard cell library. Aimed at the potential limiting factor of improving the performance of memory hierarchy, corresponding optimization techniques of critical elements in memory system are explored finally.

关键词： System-on-a-chip Elliptic curve cryptography Hardware Costs Algorithm design and analysis Random access memory Clocks Registers Elliptic curves Protection

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