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Research on self-similar network traffic prediction

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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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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An Efficient Algorithm for the Least Areas Path Problem

An Efficient Algorithm for the Least Areas Path Problem

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

作者： Gaojun Fan Shiyao Jin Ational Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha Hunan China

The goal of the least areas path problem (LAPP) is to find a path traversing through a given region covered by a set of areas with any arbitrary shape, between a given pair of points and with the property that each point on the path is covered by the least areas. Different the weighted region optimal path problem, the LAPP asks for the cost of each step in path is as low as possible. Based on the relationship between boundaries of sub-regions and the least areas path, we can transform this continuous-domain problem to a discrete one by calculating the coverage of curves of sub-regionspsila boundaries. Depending on binary-search and breadth-first-search, an efficient and fast algorithm was devised for solving the LAPP.

关键词： Algorithm design and analysis Ad hoc networks Approximation algorithms Complexity theory Strontium Approximation methods Computational geometry

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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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Load scheduling: Reducing Pressure on distributed Register files for free 08

Load scheduling: Reducing Pressure on Distributed Register f...

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2008 Asia and South Pacific Design Automation Conference (ASP-DAC 2008), part 1

作者： Mei Wen Nan Wu Maolin Guan Chunyuan Zhang National Laboratory for Parallel & Distributed Processing Chang Sha Hu Nan P.R. of China

ISBN: (纸本)9781424419227

In this paper we describe load scheduling, a novel method that balances load among register files by residual resources. Load scheduling can reduce register pressure for clustered VLIW processors with distributed register files while not increasing VLIW scheduling length. We have implemented load scheduling in compiler for Imagine and FT64 stream processors. The result shows that the proposed technique effectively reduces the number of variables spilled to memory, and can even eliminate it. The algorithm presented in this paper is extremely efficient in embedded processor with limited register resource because it can improve registers utilization instead of increasing the requirement for the number of registers.

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Optimization approaches of organizing streams on imagine processor

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Jisuanji Xuebao/Chinese Journal of Computers 2008年第7期31卷 1092-1100页

作者： Yang, Xue-Jun Zeng, Li-Fang Deng, Yu Tang, Yu-Hua National Key Laboratory of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Jiangnan Remote Sensing Institute Shanghai 200072 China

Due to the characteristics of stream applications and the insufficiency of conventional processors when running stream programs, stream processors which support data-level parallelism become the research hotspot. This paper presents two means, stream partition (SP) and stream compression (SC), to optimize streams on Imagine. The results of simulation show that SP and SC can make stream applications take full advantage of the parallel clusters, pipelines and three-level memory hierarchy of the Imagine processor, and then reduce the execution time of stream programs.

关键词： parallel processing systems

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Modelling with relational calculus of object and component systems - RCOS

Modelling with relational calculus of object and component s...

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作者： Chen, Zhenbang Hannousse, Abdel Hakim Van Hung, Dang Knoll, Istvan Li, Xiaoshan Liu, Zhiming Liu, Yang Nan, Qu Okika, Joseph C. Ravn, Anders P. Stolz, Volker Yang, Lu Zhan, Naijun International Institute for Software Technology United Nations University China Faculty of Science and Technology University of Macau Department of Computer Science Aalborg University Denmark Lab. of Computer Science Institute of Software CAS China National Laboratory for Parallel and Distributed Processing China

ISBN: (纸本)3540852883

This chapter presents a formalization of functional and behavioural requirements, and a refinement of requirements to a design for CoCoME using the Relational Calculus of Object and Component Systems (rCOS). We give a model of requirements based on an abstraction of the use cases described in Chapter 3.2. Then the refinement calculus of rCOS is used to derive design models corresponding to the top level designs of Chapter 3.4. We demonstrate how rCOS supports modelling different views and their relationships of the system and the separation of concerns in the development. © 2008 Springer-Verlag Berlin Heidelberg.

关键词： Calculations

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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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