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International Symposium on parallel and distributed processing with Applications, ISPA

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

Imagine stream processor has shown high performance and efficiency for media applications. Its potential for scientific applications is of great interest to the high performance computing community. This paper investigates this subject from a new angle. It roughly classifies the scientific programs into three classes based on their computation to memory access ratios. For each class, typical programs are programmed with StreamC/KernelC stream language and simulated based on the cycle-accurate simulator of Imagine. In-depth analysis is carried out for the performance data, with special attentions on the performance bottlenecks. The performance data obtained on Imagine are compared against data on two general-purpose x86 processors. The results show that programs with no DRAM accesses attain high floating point performance and efficiencies on Imagine. These programs' performance is only restricted by limited ILP (Instruction-Level parallelism) and load imbalance across ALUs. Programs with computation to memory operation ratios O(n) attain absolute floating point performance on Imagine comparable to that obtained on general-purpose processors, but their floating-point efficiencies are not satisfactory. It is essential to optimize these programs for high SRF (Stream Register File) and LRF (Local Register File) reuse and high ILP on Imagine. Programs with lower computation to memory operation ratios attain much lower floating-point performance and efficiencies on Imagine, compared to those obtained on x86 processors.

关键词： Image analysis Streaming media Analytical models Computer architecture Computational modeling High performance computing Bandwidth Arithmetic Application software Scientific computing

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Automating Software FMEA via Formal Analysis of Dependence Relations

Automating Software FMEA via Formal Analysis of Dependence R...

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IEEE Annual International Computer Software and Applications Conference (COMPSAC)

作者： Wei Dong Ji Wang Changzhi Zhao Xian Zhang Jie Tian School of Computer National University of Defense Technology China National Laboratory for Parallel and Distributed Processing China

The paper presents the ongoing work of studying FMEA method for embedded safely critical software via formal analysis of various dependence relations among software elements, which can fairly improve the automation and precision of both system level and detailed level FMEA. These dependence relations are depicted by the formal models abstracted from software design and implementation, and the FMEA processes for both structural and object-oriented software are proposed respectively. The initial result of case study shows the effectiveness of the approach.

关键词： Software Unified modeling language Safety Aircraft Object oriented modeling Atmospheric modeling Software reliability

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Research on self-similar network traffic prediction

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Hunan Daxue Xuebao/Journal of Hunan University Natural sciences 2008年第6期35卷 82-86页

作者： Zhang, Guang-Sheng Li, Jing-Bo Dou, Wen-Hua Shao, Li-Song National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China Journal of Hunan University Changsha 410082 China

Recent studies on network traffic have shown that self-similar is very popular, and the character will not be changed during buffering, switching and transmitting. The character self-similar must be considered in network traffic prediction. This paper analyzed and summarized the research results of self-similar network traffic prediction from the fields of self-similar modeling, parameter computing and performance prediction. An equivalent bandwidth algorithm of self-similar traffic prediction based on measurement was put forward. Our analysis has shown that the algorithm can effectively reduce computing and realizing complexities.

关键词： Parameter estimation

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Compiler-Assisted Application-Level Checkpointing for MPI Programs

Compiler-Assisted Application-Level Checkpointing for MPI Pr...

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IEEE International Conference on distributed Computing Systems

作者： Xuejun Yang Panfeng Wang Hongyi Fu Yunfei Du Zhiyuan Wang Jia Jia National Laboratory for Parallel & Distributed Processing College of Computer National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9781424431748

Application-level checkpointing can decrease the overhead of fault tolerance by minimizing the amount of checkpoint data. However this technique requires the programmer to manually choose the critical data that should be saved. In this paper, we firstly propose a live-variable analysis method for MPI programs. Then, we provide an optimization method of data saving for application-level check-pointing based on the analysis method. Based on the theoretical foundation, we implement a source-to-source pre-compiler (ALEC) to automate application-level checkpointing. Finally, we evaluate the performance of five FOR-TRAN/MPI programs which are transformed and integrated checkpointing features by ALEC on a 512-CPU cluster system. The experimental results show that i)the application-level checkpointing based on live-variable analysis for MPI programs can efficiently reduce the amount of checkpoint data, thereby decrease the overhead of checkpoint and restart;ii)ALEC is capable of automating application-level checkpointing correctly and effectively.

关键词： checkpointing message passing mannose phosphate isomerase remote procedure calls artificial lung expanding compound optimization method Checkpoints Computer personnel Fault tolerance application layer

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Optimal Placement of Application-Level Checkpoints

Optimal Placement of Application-Level Checkpoints

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

作者： Panfeng Wang Zhiyuan Wang Yunfei Du Xuejun Yang Haifang Zhou National Laboratory for Parallel and Distributed Processing College of Computer National University of Defense Technology Changsha Hunan China

One of the basic problems related to the efficient application-level checkpointing is the placement of checkpoints in the source codes. In this paper we discuss two common questions with a source-to-source precompiler ALEC: 1) if there are N checkpoints in the application's source code, how to pick M checkpoints out of them minimizing the total amount of checkpoint data? 2) if there are no checkpoint in the application's source code, how to insert a set of checkpoints minimizing the amount of checkpoint data? We reveal that these two questions can both be abstracted as a mathematic model which is similar to the 0-1 integer programming model, and the model can be solved using implicit enumeration method. The solving methods proposed in the paper have been implemented and integrated into ALEC. Experimental results show that the method is efficient.

关键词： Checkpointing Fault tolerance Fault tolerant systems Program processors Computers Flow graphs Data structures

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Static Analysis for Application-Level Checkpointing of MPI Programs

Static Analysis for Application-Level Checkpointing of MPI P...

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

作者： Panfeng Wang Yunfei Du Hongyi Fu Xuejun Yang Haifang Zhou National Laboratory for Parallel and Distributed Processing College of Computer National University of Defense Technology Changsha Hunan China

Application-level checkpointing is a promising technology in the domain of large-scale scientific computing. The consistency of global checkpoint must be carefully guaranteed in order to correctly restore the computation. Usually, some complex coordinated protocols are employed to ensure the consistency of global checkpoint, which require logging orphan or in-transit messages during checkpointing. These protocols complicate the recovery of the computation and increase the checkpoint overhead due to logging message. In this paper, a new method which ensures the consistency of global checkpoint by static analysis is proposed. The method identifies the safe checkpointing regions in MPI programs, where the global checkpoint is always strongly consistent. All checkpoints are located in those safe checkpoint regions. During checkpointing, the method will not log any messages and introduce no extra overhead. The method was implemented and integrated into ALEC, which is a source-to-source precompiler for automating application-level checkpointing. The experimental results show that our method is effective.

关键词： Checkpointing Algorithms Flow graphs Protocols Fault tolerance Fault tolerant systems parallel machines

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Flexible Routing in Grouped DHTs

Flexible Routing in Grouped DHTs

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International Conference on Peer-to-Peer Computing

作者： Yiming Zhang Dongsheng Li Lei Chen Xicheng Lu National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China Department of Computer Science Hong Kong University of Science and Technology Hong Kong China

In most DHTs proposed so far, all nodes are assumed to be homogeneous, and all messages are routed using a common algorithm. In practice, however, nodes in large-scale systems might be heterogeneous with respect to their capabilities, reputations, affiliations of administrative domains, and so on, which consequently makes it preferable to distinguish the heterogeneity of participant nodes. To achieve this, in this paper we present grouped tapestry (GTap), a novel tapestry-based DHT that supports organizing nodes into groups and allows flexible DHT routing. The effectiveness of our proposals is demonstrated through theoretical analysis and extensive simulations.

关键词： Routing Fingers Peer to peer computing Maintenance engineering Security Availability Data structures

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distributed Line Graphs: A Universal Framework for Building DHTs Based on Arbitrary Constant-Degree Graphs

Distributed Line Graphs: A Universal Framework for Building ...

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International Conference on distributed Computing Systems

作者： Yiming Zhang Ling Liu Dongsheng Li Xicheng Lu National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China Georgia Institute of Technology College of Computing Georgia Institute of Technology Atlanta USA

ISBN: (纸本)9781424431748

Most proposed DHTs have their unique maintenance mechanisms specific to the static graphs on which they are based. In this paper we propose distributed line graphs (DLG), a universal framework for building DHTs based on arbitrary constant-degree graphs. We prove that in a DLG-enabled, N-node DHT, the out-degree is d, the in-degree is between 1 and 2d, and the diameter is less than 2(log d N-log d N 0 +D 0 +1), where d, D 0 and N 0 represent the degree, diameter and number of nodes of the initial graph, respectively. The maintenance cost of DLG-enabled DHTs is O(log d N). We show the power of DLG technique by applying it to Kautz graphs to propose a new DHT scheme.

关键词： Routing Maintenance engineering Buildings Distance measurement Topology Industries Construction industry

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An Efficient Approximation for Weapon-Target Assignment

An Efficient Approximation for Weapon-Target Assignment

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ISECS International Colloquium on Computing, Communication, Control, and Management, CCCM

作者： Lina Chen ChuanJun Ren Su Deng C4ISR Technology National Defense Science and Technology Key Laboratory National University of Defense Technology Changsha Hunan China National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha Hunan China

The weapon-target assignment (WTA) problem is a fundamental problem arising in defense-related applications of operations research. The WTA problem can be formulated as a nonlinear integer programming problem and is known to be NP-complete. We present firstly a technique founded on the use weapon cell, which enables one-to-many mapping about weapon-target to become one-to-one mapping. Next, we introduce a framework of solving the WTA problem. Based on this framework, an approximation algorithm that is grounded on the rules about weapon cells and targets is proposed. Finally, the simulative results show that the proposed algorithm indeed is very efficient.

关键词： Weapons Heuristic algorithms Algorithm design and analysis Resource management Artificial neural networks Genetic algorithms Operations research

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An Efficient Approach for Point Coverage Problem of Sensor Network

An Efficient Approach for Point Coverage Problem of Sensor N...

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International Symposium on Electronic Commerce and Security

作者： GaoJun Fan Feng Liang ShiYao Jin National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha Hunan China Military Representative Office of Navy Chinese Shipbuilding Company Limited Shanghai China

ISBN: (纸本)9780769532585

One fundamental issue in application of wireless sensor networks is to provide proper coverage of their deployment regions, which answers the questions about the quality of service (surveillance or monitoring) that can be provided by a sensor network. In this paper, we consider the point-coverage problem where a given set of n points requires to be covered in the two-dimension (such as monitoring leakage of hazardous gaseous materials at ventilation points or observing the fixed location important targets). Our objective is to place the minimal number sensors such that coverage points in the field can be covered by at least k sensors. By combining computational geometry and combinatorics techniques, we investigate the issue from a different angle, demonstrate an important relationship between coverage points and sensors, and develop an efficient algorithm for 1-coverage problem. Finally, we indicate our approach can easily solve k-coverage problem based on 1-coverage.

关键词： Wireless sensor networks Sensors Monitoring Ad hoc networks Tin Computational geometry Wireless communication

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