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International Conference on Cyber-Enabled distributed Computing and Knowledge Discovery, CyberC

作者： Lixia Liu Gang Hu Ming Xu Yuxing Peng National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha China Department of Networks Engineering School of Computer National University of Defense Technology Changsha China

In the relay-trading mode of wireless cognitive radio networks the secondary user (SU) can achieve a promised spectrum access opportunity by relaying for the primary user (PU). How to utilize the exchanged resource efficiently and fairly is an interesting and practical problem. In this paper we proposed a cooperative spectrum sharing strategy (RT-CSS) for the relay-trading mode from the fairness view. The cooperative SUs are gathered in a cooperative sharing group (CSG), and contribution metric (CM) is proposed to measure each CSG member's contribution to CSG as well as benefit from CSG. The adjustment of CM can guarantee the fairness and efficiency of spectrum sharing. The numerical simulation shows that RT-CSS can achieve better performance than the sense-uncooperative mode.

关键词： Relays Cognitive radio Measurement Qualifications Wireless sensor networks Radio networks

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Betweenness-based algorithm for a partition scale-free graph

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Chinese Physics B 2011年第11期20卷 556-564页

作者：张百达吴俊杰唐玉华周静 National Laboratory for Parallel and Distributed Processing School of ComputersNational University of Defense Technology Department of Computer Science and Technology School of ComputersNational University of Defense Technology

Many real-world networks are found to be scale-free. However, graph partition technology, as a technology capable of parallel computing, performs poorly when scale-free graphs are provided. The reason for this is that traditional partitioning algorithms are designed for random networks and regular networks, rather than for scale-free networks. Multilevel graph-partitioning algorithms are currently considered to be the state of the art and are used extensively. In this paper, we analyse the reasons why traditional multilevel graph-partitioning algorithms perform poorly and present a new multilevel graph-partitioning paradigm, top down partitioning, which derives its name from the comparison with the traditional bottom-up partitioning. A new multilevel partitioning algorithm, named betweenness-based partitioning algorithm, is also presented as an implementation of top-down partitioning paradigm. An experimental evaluation of seven different real-world scale-free networks shows that the betweenness-based partitioning algorithm significantly outperforms the existing state-of-the-art approaches.

关键词： graph partitioning betweenness-based partitioning algorithm scale free network

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Topology-Aware Deployment of Scientific Applications in Cloud Computing

Topology-Aware Deployment of Scientific Applications in Clou...

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IEEE International Conference on Cloud Computing, CLOUD

作者： Pei Fan Zhenbang Chen Ji Wang Zibin Zheng Michael R. Lyu National Laboratory for Parallel & Distributed Processing National University of Defense Technology Changsha P.R.China Dept. of Computer Science & Engineering The Chinese University of Hong Kong Hong Kong China

Nowadays, more and more scientific applications are moving to cloud computing. The optimal deployment of scientific applications is critical for providing good services to users. Scientific applications are usually topology-aware applications. Therefore, considering the topology of a scientific application during the development will benefit the performance of the application. However, it is challenging to automatically discover and make use of the communication pattern of a scientific application while deploying the application on cloud. To attack this challenge, in this paper, we propose a framework to discover the communication topology of a scientific application by pre-execution and multi-scale graph clustering, based on which the deployment can be optimized. Comprehensive experiments are conducted by employing a well-known MPI benchmark and comparing the performance of our method with those of other methods. The experimental results show the effectiveness of our topology-aware deployment method.

关键词： Topology Clustering algorithms Benchmark testing Cloud computing Partitioning algorithms Clustering methods Throughput

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Intention oriented itinerary recommendation by bridging physical trajectories and online social networks

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Ruan Jian Xue Bao/Journal of Software 2012年第SUPPL.期23卷 159-168页

作者： Meng, Xiang-Xu Wang, Xiao-Dong Zhou, Xing-Ming National Key Laboratory of Parallel and Distributed Processing College of Computer Science National University of Defense Technology Changsha 410073 China

Human itineraries are often initiated by some general intentions and will be optimized after considering all kinds of constraints and available information. This paper proposes a category-based itinerary recommendation framework to help the user transfer from intentions to itinerary planning, which join physical trajectories and information of location based social networks. The main contributions are: (1) Build the category based activity scheduling model;(2) Design and implement the category tree based POI (point or interest) query strategy and algorithm;(3) Propose the Voronoi graph based GPS trajectory analysis method to build traffic information networks;(4) Combine social networks with traffic information networks to implement category based recommendation by ant colony algorithm. The study conducts experiments on datasets from FourSquare and GeoLife project. A test on satisfaction of recommended items is also performed. Results show that the satisfaction reaches 80% in average.

关键词： Trajectories

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Jammer Localization for Wireless Sensor Networks

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电子学报(英文版) 2011年第4期20卷 735-738页

作者： SUN Yanqiang WANG Xiaodong ZHOU Xingming National Key Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Changsha China

Jamming attack can severely affect the performance of Wireless sensor networks (WSNs) due to the broadcast nature of wireless medium. In order to localize the source of the attacker, we in this paper propose a jammer localization algorithm named as Minimum-circlecovering based localization (MCCL). Comparing with the existing solutions that rely on the wireless propagation parameters, MCCL only depends on the location information of sensor nodes at the border of the jammed region. MCCL uses the plane geometry knowledge, especially the minimum circle covering technique, to form an approximate jammed region, and hence the center of the jammed region is treated as the estimated position of the jammer. Simulation results showed that MCCL is able to achieve higher accuracy than other existing solutions in terms of jammer's transmission range and sensitivity to nodes' density.

关键词：无线传感器网络干扰定位传感器节点位置信息覆盖技术定位算法无线传播几何知识

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Security Issues and Solutions in Cloud Computing

Security Issues and Solutions in Cloud Computing

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International Conference on distributed Computing Systems Workshop

作者： Pengfei You Yuxing Peng Weidong Liu Shoufu Xue 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 CPLA Air Defence Forces Command Academy Zhengzhou Henan China

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.

关键词： Cloud computing Computational modeling Virtual machine monitors Operating systems Cryptography

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P-Tracer: Path-Based Performance Profiling in Cloud Computing Systems

P-Tracer: Path-Based Performance Profiling in Cloud Computin...

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IEEE Annual International Computer Software and Applications Conference (COMPSAC)

作者： Haibo Mi Huaimin Wang Hua Cai Yangfan Zhou Michael R. Lyu Zhenbang Chen National Lab for Parallel & Distributed Processing National Univ. of Defense Technology Changsha China Computing Platform Alibaba Cloud Computing Company Hangzhou China Dept. of Computer Science & Engineering The Chinese Univ. of Hong Kong Hong Kong

In large-scale cloud computing systems, the growing scale and complexity of component interactions pose great challenges for operators to understand the characteristics of system performance. Performance profiling has long been proved to be an effective approach to performance analysis; however, existing approaches do not consider two new requirements that emerge in cloud computing systems. First, the efficiency of the profiling becomes of critical concern; second, visual analytics should be utilized to make profiling results more readable. To address the above two issues, in this paper, we present P-Tracer, an online performance profiling approach specifically tailored for large-scale cloud computing systems. P-Tracer constructs a specific search engine that adopts a proactive way to process performance logs and generates particular indices for fast queries; furthermore, PTracer provides users with a suite of web-based interfaces to query statistical information of all kinds of services, which helps them quickly and intuitively understand system behavior. The approach has been successfully applied in Alibaba Cloud Computing Inc. to conduct online performance profiling both in production clusters and test clusters. Experience with one real-world case demonstrates that P-Tracer can effectively and efficiently help users conduct performance profiling and localize the primary causes of performance anomalies.

关键词： Cloud computing Instruments Postal services Search engines Shape System performance Production

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A performance study of CSMA in wireless networks with successive interference cancellation

A performance study of CSMA in wireless networks with succes...

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IEEE International Conference on Communications (ICC)

作者： Shaohe Lv Weihua Zhuang Xiaodong Wang Chi Liu Xiaofeng Hu Yipin Sun Xingming Zhou Institute of Network Information and Security National University of Defense Technology Changsha China Department of Electrical and Computer Engineering University of Waterloo Waterloo ONT Canada Central South University Changsha China National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China

Successive interference cancellation (SIC) is an effective way of multipacket reception to combat interference. As conventional CSMA (Carrier Sense Multiple Access) is designed for single packet reception, it is unclear whether or not CSMA performs well to exploit the SIC capability. In this paper, we analyze the performance of a simple CSMA protocol in a network with SIC. For a given link, we derive the residing areas of an interfering node when simultaneous transmission is allowed and when the interference is harmful, respectively. We show that, though SIC provides many new transmission opportunities, CSMA cannot effectively exploit them. There is a fundamental tradeoff in a CSMA protocol between exploiting the transmission opportunities from SIC and capturing the harmful interference. In many cases, when CSMA achieves its best performance, almost all new transmission opportunities are not exploited. It is therefore very necessary to design a new distributed access protocol in wireless networks with SIC.

关键词： Silicon carbide Multiaccess communication Interference Receivers Propagation losses Protocols Wireless networks

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Storage allocation for redundancy scheme in reliability-aware cloud systems

Storage allocation for redundancy scheme in reliability-awar...

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2011 IEEE 3rd International Conference on Communication Software and Networks, ICCSN 2011

作者： Huang, Zhen Yuan, Yuan Peng, Yuxing National Laboratory of Parallel and Distributed Processing Computer Department National University of Defense Technology Changsha China

ISBN: (纸本)9781612844855

As the burst increasing of created and demand on information and data, the efficient solution on storage management is highly required in the cloud storage systems. As an important component of management, storage allocation scheme aims to use a low redundancy and also to achieve a high reliability. However, the two aims are hard to be unified. Considering the practical situation of Cloud systems, we propose a systematic storage allocation scheme to touch them both. And we also study the impact of many factors to the data reliability. © 2011 IEEE.

关键词： Information management

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Research on online failure prediction model and status pretreatment method for exascale system

Research on online failure prediction model and status pretr...

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3rd International Conference on Cyber-Enabled distributed Computing and Knowledge Discovery, CyberC 2011

作者： Zhou, Hao Jiang, Yanhuang National Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Changsha China

ISBN: (纸本)9780769545578

The reliability issue of Exascale system is extremely serious. Traditional passive fault-tolerant methods, such as rollback-recovery, can not fully guarantee system reliability any more because of their large executing overhead and long recovering duration. Active fault tolerance is expected to become another important fault-tolerant approach for Exascale system. Focusing on system failure prediction, which is one key step of active fault tolerance, we construct online failure prediction model and research on the effective method of system status pretreatment. In order to improve the accuracy and real-time feature of current methods, the proposed Improved Adaptive Semantic Filter (IASF) method processes the latest system logs regularly, filtering useless information out of them according to their semantics. Adopting the main idea of Vector Space Model (VSM), IASF method creates Event Vector corresponding to each log record. By calculating the cosine of vectorial angle, it evaluates the semantics correlation between different log records, and then executes temporal and spatial redundant filter considering the burst feature of log records. IASF method is insensitive to the type of system log and does not introduce any expert system or domain knowledge. The experiment result shows that system can eliminate about 99.6% of useless log records after executing IASF method. © 2011 IEEE.

关键词： Fault tolerance

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