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Simulation-based evaluation of the Imagine stream processor with scientific programs

International Journal of High Performance Computing and Networking 2012年第2期7卷 99-110页

作者： Che, Yonggang Xu, Chuanfu Lu, Pingjing Wang, Zhenghua National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 Hunan China

This paper evaluates the performance and efficiency of Imagine stream processor for scientific programs. It classifies scientific programs into three classes based on their computation to memory access ratios. Typical programs are selected and measured on a simulated Imagine and two general-purpose processors. Comparative analysis is made with special attentions on the computational efficiency, power efficiency and performance bottleneck. The results show that programs in Class 1 attain high performance and high computational efficiency on Imagine. Their performance is only restricted by limited ILP and load imbalance across ALUs. Programs in Class 2 attain moderate performance but non-satisfactory computational efficiency on Imagine due to limited LRF and SRF reuse. Programs in Class 3 attain extremely low performance on Imagine because most of the execution time is spent on DRAM accesses. The estimated power efficiency on Imagine is excellent except for programs in Class 3. Copyright © 2012 Inderscience Enterprises Ltd.

关键词： Computational efficiency

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A modified estimation scheme of EBT algorithm for RFID system

A modified estimation scheme of EBT algorithm for RFID syste...

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International Conference on Intelligent Control and Information processing (ICICIP)

作者： Ruisi Zhao Yulu Yang Parallel and distributed processing laboratory Department of Computer Science and Technology Nankai University Tianjin China

The paper proposes a scheme to improve the accuracy of tag estimation in the EBT algorithm in RFID system. In the proposed scheme, the mean value of the estimated tag number should be acquired before calculating the optimal prefix. And the circular queue is used to record the average tag number which has been acquired recently. Thought the computer simulation we proposed the optimal length of the queue and make an explanation why the circular queue should be used to store the average tag number. The proposed scheme makes a better system performance compared with the original EBT algorithm.

关键词： Estimation Heuristic algorithms Algorithm design and analysis Radiofrequency identification Binary trees Accuracy Computer simulation

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UCBench: A user-centric benchmark suite for C code static analyzers

UCBench: A user-centric benchmark suite for C code static an...

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International Conference on Information Science and Technology (ICIST)

作者： Jiangchao Liu Liqian Chen Longming Dong Ji Wang National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China

In recent years, many C code static analyzers, with different abilities of bug detection, have appeared and been applied in various domains. There are so many choices that it becomes hard for programmers to know in detail the strengths as well as limitations of all these analyzers and to find the most suitable ones for their code. In this paper, we propose a benchmark for C code static analyzers, named UCBench, to provide quantitative and qualitative measurements for evaluating analyzers. Being different from other benchmarks, UCBench concentrates more on users' requirements rather than the improvements of bug detecting technique itself. The major components of UCBench include test case database, evaluation metrics and harness. We classify test cases into several groups according to their attributes and design various user-centric evaluation metrics. Besides, we develop some harness to automate the evaluation process. Finally, we demonstrate our benchmark suite over four C code static analyzers: Flawfinder, Cppcheck, Uno and Splint.

关键词： Benchmark testing Libraries Measurement Computer bugs Databases Standards Monitoring

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Precise pointer analysis for list-manipulating programs based on quantitative separation logic

Precise pointer analysis for list-manipulating programs base...

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International Conference on Information Science and Technology (ICIST)

作者： Longming Dong Liqian Chen Jiangchao Liu Renjian Li National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China

Full precise pointer analysis has been a challenging problem, especially when dealing with dynamically-allocated memory. Separation logic can describe pointer alias formally, but cannot describe the quantitative reachability between pointers. In this paper, we present a symbolic framework for analyzing the reachability between pointers in list-manipulating programs. The precise points-to relations of pointers in lists are described by formulae of quantitative separation logic (QSL), and the analysis framework is based on the operational and rearrangement rules about the assignments of pointers. The fixpoint calculus and the counter symbolic abstraction are used to find loop invariants. We can get precise relations between pointers at each point of list-manipulating programs. In the end, several initial examples about list-manipulating programs are given to show that the approach can get precise pointer analysis for list-manipulating programs.

关键词： Radiation detectors Shape Instruments Calculus Semantics Data structures Argon

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Security issues and solutions in cloud computing

Security issues and solutions in cloud computing

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32nd IEEE International Conference on distributed Computing Systems Workshops, ICDCSW 2012

作者： You, Pengfei Peng, Yuxing Liu, Weidong Xue, Shoufu National Key Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China Jiangsu Automation Research Institute Jiangsu China Air Defense Forces Academy CPLA Zhengzhou Henan China

ISBN: (纸本)9781467314237

Recently, Cloud computing, as one of the hottest words in IT world, has drawn great attention. Many IT companies such as IBM, Google, Amazon, Microsoft, Yahoo and others vigorously develop cloud computing systems and related products to customers. However, there are still some difficulties for customers to adopt cloud computing, in which many security issues exist, because data for a customer is stored and processed in cloud, not in a local machine. This paper briefly introduces cloud computing and its key concepts. In particularly, we intend to discuss security requirements and security issues involving data, application and virtualization in cloud computing, as well as current solutions to these issues. © 2012 IEEE.

关键词： Virtualization

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Invalid Pointer Dereferences Detection for CPS Software Based on Extended Pointer Structures

Invalid Pointer Dereferences Detection for CPS Software Base...

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International Conference on Secure Software Integration and Reliability Improvement Companion (SSIRI-C)

作者： Longming Dong Wei Dong Liqian Chen National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China

Invalid pointer dereferences, such as null pointer dereferences, dangling pointer dereferences and double frees, are a prevalent source of software bugs in CPS software, due to flexible dereferencing pointers along various pointer fields. Existing tools have high overhead or are incomplete, thereby limiting their efficiency in checking the kind of CPS software with shared and mutable memory. In this paper, we present a novel extended pointer structure for detecting all invalid pointer dereferences in this kind of CPS software. We propose an invalid pointer dereferences detection algorithm based on the uniform transformation of abstract heap states. Experimental evaluation about a set of large C benchmark programs shows that the proposed approach is sufficiently efficient in detecting invalid pointer dereferences of CPS software with shared and mutable memory.

关键词： Abstracts Software Frequency modulation Semantics Switches Detection algorithms Runtime

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Skyline Query processing on Interval Uncertain Data

Skyline Query Processing on Interval Uncertain Data

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IEEE International Symposium on Object/Component/Service-Oriented Real-Time distributed Computing Workshops (ISORCW)

作者： Xiaoyong Li Yijie Wang Xiaoling Li Guangdong Wang National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

Many recent applications involve processing and analyzing uncertain data. Recently, several research efforts have addressed answering skyline queries efficiently on massive uncertain datasets. However, the research lacks methods to compute these queries on uncertain data, where each dimension of the uncertain object is represented as an interval or an exact value. In this paper, we extensively study the problem of skyline query on these interval based uncertain objects, which has never been studied before. We first model the problem of querying the skylines on interval datasets. Typically, we address two efficient algorithms with I/O optimal for the conventional interval skyline queries and constrained interval skyline queries, respectively. Extensive experiments demonstrate the efficiency of all our proposed algorithms.

关键词： Probability density function Distribution functions Probability distribution Random variables Computational modeling Uncertainty distributed databases

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A study of strategies to restrain the C&C activities of structured P2P botnets

A study of strategies to restrain the C&C activities of stru...

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International Conference on Computer Sciences and Convergence Information Technology (ICCIT)

作者： Tianzuo Wang Bo Liu Huaimin Wang Hao Ren Xiaolong Ma School of Computer Science National Laboratory for Parallel and Distributed Processing National University of Defense and Technology Changsha China

Botnets are threatening the Internet heavily, and more and more botnets are utilizing the P2P technology to build their C&C (Command and Control) mechanisms. Some research have been made to compare the resilience of structured P2P botnets and unstructured ones, against elimination of nodes, but the problem that which eliminating strategy is the best is rarely studied. In this paper, we proposed a new metric called the half point, to measure the effectiveness of different strategies. We also selected seven different eliminating strategies and compared them. Through extensive simulations, we find that RBC is the best eliminating strategy. Further analysis shows that for the strategy RBC, the average degree of nodes in the botnet have the most significant influence. The bigger the average degree is, the bigger the half point of RBC is, which implies that node eliminating may not be a reasonable choice for mitigating botnets with big average degree. Results of this paper can provide guidance for restraining structured P2P botnets.

关键词： C&C mechanism betweenness centrality coreness eliminating strategy half point restrain structured P2P botnets

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SMP-SIM: An event-driven performance simulator for SMP

SMP-SIM: An event-driven performance simulator for SMP

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International Conference on Systems and Informatics (ICSAI)

作者： Xin Zhang Yuhua Tang Yufei Lin Xinhai Xu Xiaowei Guo Xiaoguang Ren National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha Hunan China

Performance prediction for the high performance computer system is of great importance for designing, implementing, and optimizing system. As a widely used technique for predicting performance, simulation method attracts more and more attention from the research community. Based on analyzing the problems in the current performance simulation techniques, we present a key idea of the performance simulator for SMP system based on event-driven. We propose the framework of SMP-SIM and implement it based on MPICH2. The simulation results show that, our simulation technique has the advantages of high accuracy and simulation performance.

关键词： Computational modeling Switches Clocks Educational institutions Computers Predictive models Analytical models

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Bodhi: Detecting Buffer Overflows with a Game

Bodhi: Detecting Buffer Overflows with a Game

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International Conference on Secure Software Integration and Reliability Improvement Companion (SSIRI-C)

作者： Jie Chen Xiaoguang Mao School of Computer National University of Defense Technology Changsha China National Laboratory for Parallel and Distributed Processing Changsha China

Buffer overflow is one of the most dangerous and common vulnerabilities in CPS software. Despite static and dynamic analysis, manual analysis is still heavily used which is useful but costly. Human computation harness humans' time and energy in a way of playing games to solve computational problems. In this paper we propose a human computation method to detect buffer overflows that does not ask a person whether there is a potential vulnerability, but rather a random person's idea. We implement this method as a game called Bodhi in which each player is shown a piece of code snippet and asked to choose whether their partner would think there is a buffer overflow vulnerability at a given position in the code. The purpose of the game is to make use of the rich distributed human resource to increase effectiveness of manual detection for buffer overflows. The game has been proven to be efficient and enjoyable in practice.

关键词： Games Buffer overflow Humans Software Servers Manuals Programming

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