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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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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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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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Towards estimating expected sizes of probabilistic skylines

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science China(Information sciences) 2011年第12期54卷 2574-2584页

作者： YANG YongTao & WANG YiJie National Key laboratory for parallel and distributed processing, school of computer, National University of Defense technology, Changsha 410073, China 1. National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China

We consider the maximal vector problem on uncertain data, which has been recently posed by the study on processing skyline queries over a probabilistic data stream in the database context. Let D n be a set of n points in a d-dimensional space and q (0 < q 1) be a probability threshold; each point in D n has a probability to occur. Our problem is concerned with how to estimate the expected size of the probabilistic skyline, which consists of all the points that are not dominated by any other point in D n with a probability not less than q. We prove that the upper bound of the expected size is O(min{n, (- ln q)(ln n) d-1 }) under the assumptions that the value distribution on each dimension is independent and the values of the points along each dimension are distinct. The main idea of our proof is to find a recurrence about the expected size and solve it. Our results reveal the relationship between the probability threshold q and the expected size of the probabilistic skyline, and show that the upper bound is poly-logarithmic when q is not extremely small.

关键词： probabilistic skyline probabilistic data streams expected size

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A Compact Model for Multi-Island Single Electron Transistors

A Compact Model for Multi-Island Single Electron Transistors

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3rd IEEE International NanoElectronics Conference (INEC)/Symposium on Nanoscience and Nanotechnology in China

作者： Chi, Yaqing Zhong, Haiqin Zhang, Chao Fang, Liang National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Hunan 410073 China

ISBN: (纸本)9781424435449

Multi-island single electron transistor is an important kind of the single electron transistor, which is convenient to realize the controllable room temperature operation. A novel semi-empirical compact model for the Multi-island single electron transistor is proposed. The new approach combines the orthodox theory of the single electron tunneling through single coulomb island and a novel empirical analysis procedure for the chain of multi coulomb islands to solve the current of the whole multi-island single electron transistor. The tunneling rates are calculated based on the orthodox theory for the single electron tunneling. The tunneling currents representing the first splitted peaks in the coulomb oscillation curves are calculated according to the assumption that the currents through all the coulomb islands are equal to each other at the stable states, while the currents representing the other splitted peaks are constructed and merged together according to the empirical analysis. The model is verified by the traditional SET simulator SIMON and shows much faster calculation speed than SIMON. Therefore, the novel compact model is suitable for the large scale MISET circuit simulation.

关键词： Single Electron Transistor Coulomb Island Coulomb Oscillation Splitted Peak

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Impact of imprecise programming of memristor on building hardware neural network

Impact of imprecise programming of memristor on building har...

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2nd Annual Conference on Electrical and Control Engineering, ICECE 2011

作者： Zhu, Xuan National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology ChangSha China

ISBN: (纸本)9781424481637

The application of memristor in building hardware neural network has accepted widespread interests, and may bring novel opportunities to neural computing. However, due to the limitation of programming precision, the conductance of memristor which represents stored information may deviate from theoretical value, and thus bring error to the neural computing results. In this paper, we analyze the impact of imprecise programming on building hardeware neural network through Monte Carlo simulation on feedback layer model. The results show that the fault-tolerance ability of neural network could well adapt to these errors, which further proves the potential of building neural networks using memristors. © 2011 IEEE.

关键词： Errors

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Survey of DHT topology construction techniques in virtual computing environments

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science China(Information sciences) 2011年第11期54卷 2221-2235页

作者： ZHANG YiMing 1,2,LU XiCheng 1,2 & LI DongSheng 1,21 National laboratory for parallel and distributed processing (PDL),Changsha 410073,China 2 school of computer,National University of Defense technology,Changsha 410073,China 1. National Laboratory for Parallel and Distributed Processing (PDL) Changsha 410073 China2. School of Computer National University of Defense Technology Changsha 410073 China

The Internet-based virtual computing environment (iVCE) is a novel network computing *** characteristics of growth,autonomy,and diversity of Internet resources present great challenges to resource sharing in *** DHT overlay (DHT for short) technique has various advantages such as high scalability,low latency,and desirable availability,and is thus an important approach to realizing efficient resource *** construction is a key technique for structured overlays that realizes basic overlay functions including dynamic maintenance and message *** this paper,we first introduce the traditional techniques of DHT topology construction,focusing mainly on dynamic maintenance and message routing of typical DHTs,DHT indexing techniques for complex queries,and DHT grouping techniques for matching domain *** then present recent advances in DHT topology construction techniques in iVCE taking advantage of the characteristics of Internet ***,we discuss the future of DHT topology construction techniques.

关键词： virtual computing environments DHT overlays topology construction distributed indexing flexible routing

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An efficient two-level bitmap index for cloud data management

An efficient two-level bitmap index for cloud data managemen...

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

作者： Bin, Huang Yu-Xing, Peng School of Computer Science Wuhan University Wuhan China National Laboratory of Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

ISBN: (纸本)9781612844855

A Cloud may be seen as a type of flexible computing infrastructure consisting of many compute nodes, where resizable computing capacities can be provided to different customers. To fully harness the power of the Cloud, efficient data management is needed to handle huge volumes of data and support a large number of concurrent end users. To achieve that, a scalable and high-throughput indexing scheme is generally required. Such an indexing scheme must support parallel search to improve scalability. In this paper, we present a bitmap based indexing scheme for efficient data processing in the Cloud. Our approach can be summarized as follows. First, we build a local bitmap index for each compute node which only indexes data residing on the node. Second, we organize the compute nodes as a structured overlay and each node maintains a portion of the global index for the whole different data. The global index is also bitmap index to indicate the node each data resides in. Third, all bitmaps are compressed by adopting run-length coding for reducing storage requirement. We conduct extensive experiments on a LAN, and the results demonstrate that our indexing scheme is dynamic, efficient and scalable. © 2011 IEEE.

关键词： Information management

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Fault recovery based on parallel recomputing in transactional memory system

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2011 International Conference on Electric and Electronics, EEIC 2011

作者： Song, Wei Jia, Jia National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9783642217647

This paper addresses the issue of fault recovery in transactional memory, and proposes a method of fault recovery based on parallel recomputing in transactional memory system. This method utilizes the data-versioning mechanism of transactional memory system to avoid the extra cost of state saving, rolls back a single transaction to avoid wasting the computing time of the fault-free transactions, and adopts the parallel recomputing method to reduce the cost of fault recovery. This paper applies this method to OpenTM programs, and proposes the implementation method of parallel recomputing in OpenTM. At last, this paper tests the performance of this method through a test program. The experimental results show that, compared with the fault recovery method of rolling back a single transaction, the parallel recomputing method in transactional memory system can execute the fault recovery quickly and accurately and the method has a well scalability. © 2011 Springer-Verlag Berlin Heidelberg.

关键词： Fault tolerance

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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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