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A fast successive over-relaxation algorithm for force-directed network graph drawing

Science China(Information Sciences) 2012年第3期55卷 677-688页

作者： WANG YongXian & WANG ZhengHua national key laboratory for parallel and distributed processing, national University of Defense technology, Changsha 410073, China 1. National Key Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China

Force-directed approach is one of the most widely used methods in graph drawing research. There are two main problems with the traditional force-directed algorithms. First, there is no mature theory to ensure the convergence of iteration sequence used in the algorithm and further, it is hard to estimate the rate of convergence even if the convergence is satisfied. Second, the running time cost is increased intolerablely in drawing largescale graphs, and therefore the advantages of the force-directed approach are limited in practice. This paper is focused on these problems and presents a sufficient condition for ensuring the convergence of iterations. We then develop a practical heuristic algorithm for speeding up the iteration in force-directed approach using a successive over-relaxation (SOR) strategy. The results of computational tests on the several benchmark graph datasets used widely in graph drawing research show that our algorithm can dramatically improve the performance of force-directed approach by decreasing both the number of iterations and running time, and is 1.5 times faster than the latter on average.

关键词： graph drawing graph layout successive over-relaxation force-directed algorithm

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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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2012 IEEE International Conference on Information Science and technology, ICIST 2012

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

ISBN: (纸本)9781457703454

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. © 2012 IEEE.

关键词： C (programming language)

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Providing information services for wireless sensor networks through cloud computing

Providing information services for wireless sensor networks ...

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2012 7th IEEE Asia-Pacific Services Computing Conference, APSCC 2012

作者： You, Pengfei Peng, Yuxing Gao, Hang National Key Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha China

ISBN: (纸本)9780769548975

Wireless sensor networks (WSN) is a critical technology for information gathering covering many areas, including health-care, transportation, air traffic control and environment monitoring. Despite wide use, the fast increasing data emanating from WSN is not fully utilized due to the limitation for structure of WSN itself. Along with the further development of WSN, the data form which is not be efficiently managed and applied to supply information services for users. As the emerging IT technology, cloud computing supplies powerful utilization ability for IT resources, which makes many traditional applications migrate to cloud computing. In this paper, we propose a framework integrating cloud computing paradigm and WSN, which fully uses data process ability and service model for cloud computing. In the framework, data form WSN are efficiently utilized and managed, depending on which, information services for WSN are well provided to users. © 2012 IEEE.

关键词： Virtualization

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Research of context situation awareness technology

Research of context situation awareness technology

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作者： Shi, Dianxi Wu, Zhendong Ding, Bo Yan, Huining National Key Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9780769546698

Context situation, which means a snapshot of the status of the real world, is formed by integrating a large amount of contexts collected from various resources. How to get the context situation and use the situation to provide better services is a challenging issue. In this paper, we focused on this challenge on the basis of the mobile cloud computing architecture. An abstract model is proposed in this paper to uniformly collect the context and send them to cloud. A rule-based large-scale context aggregation algorithm is also proposed which utilizes the MapReduce computing paradigm. Finally, a large-scale context management framework based on the abstract model and the context aggregation algorithm is proposed, and a real-time traffic demo is implemented to verify the validity of the framework. © 2012 IEEE.

关键词： MapReduce

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On the feasibility of common-friend measurements for the distributed online social networks

On the feasibility of common-friend measurements for the dis...

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2012 7th International ICST Conference on Communications and Networking in China, CHINACOM 2012

作者： Fu, Yongquan Wang, Yijie National Key Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Hunan province 410073 China

ISBN: (纸本)9781467326995

distributed social networks have emerged recently. Nevertheless, recommending friends in the distributed social networks has not been exploited fully. We propose FDist, a distributed common-friend estimation scheme that estimates the number of common-friends between any pair of users without disclosing the friends' information. FDist uses privacy-preserving common-friend measurements to collect a small number of common-friend samples, and uses low-dimensional coordinates to estimate the number of common friends to other users. Simulation results on real-world social networks confirm that FDist is both scalable and accurate. © 2012 IEEE.

关键词： Social networking (online)

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BCE: A privacy-preserving common-friend estimation method for distributed online social networks without cryptography

BCE: A privacy-preserving common-friend estimation method fo...

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2012 7th International ICST Conference on Communications and Networking in China, CHINACOM 2012

作者： Fu, Yongquan Wang, Yijie National Key Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Hunan province 410073 China

ISBN: (纸本)9781467326995

distributed online social networks (DOSN) have emerged recently. Nevertheless, recommending friends in the distributed social networks has not been exploited fully. We propose BCE (Bloom Filter based Common-Friend Estimation), a scalable and privacy-preserving common-friend estimation scheme that estimates the set of common friends without the need of cryptography techniques. First, BCE denotes each user using the identifiers created by the Peer-to-Peer underlay that are robust against the dictionary attacks. Second, BCE uses a Bloom filter to represent a friend list for scalability. Third, BCE estimates common friends of two users using the intersection of Bloom filters computed by one of their common friends, which ensures the privacy of friend lists against unknown users. Our privacy analysis shows that BCE hides the privacy of each user with a high probability. Simulations over real-world social-network data sets confirms that BCE is both accurate and scalable. © 2012 IEEE.

关键词： Social networking (online)

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Topology awareness algorithm for virtual network mapping

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第3期13卷 178-186页

作者： Xiao-ling LI Huai-min WANG Chang-guo GUO Bo DING Xiao-yong LI Wen-qi BI Shuang TAN National Key Laboratory of Parallel and Distributed Processing National University of Defense Technology.Changsha 410073China School of Computer National University of Defense TechnologyChangsha 410073China China Electronic Systems Engineering Corporation Beijing 100039China The Northern Institute of Electronic Equipment of China Beijing 100083China

Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the k-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C).

关键词： Network virtualization Ossification Virtual network （VN） mapping Substrate network （SN） Topology awareness Acceptance ratio

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Concurrent access control using subcarrier signature in heterogeneous MIMO-based WLAN

Concurrent access control using subcarrier signature in hete...

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5th International Workshop on Multiple Access Communications, MACOM 2012

作者： Shen, Hu Lv, Shaohe Sun, Yanqiang Dong, Xuan Wang, Xiaodong Zhou, Xingming National Key Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China Institute of Network Information and Security National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9783642349751

In recent WLAN standards (such as IEEE 802.11n), MIMO (Multiple Input Multiple Output) is deployed to provide high data transmission rate. It is however challenging to efficiently share the channel resources among different stations/users. In this paper, we study the MAC protocol in heterogeneous MIMO-based WLAN to effectively exploit the capability of concurrent transmission. We propose a novel subcarrier encoding method, which uses frequency signatures to perform the control message exchange between the AP and multiple stations simultaneously. Afterwards, a MAC protocol, HT-MIMO MAC, is presented to support concurrent transmission in both the uplink and downlink directions. HT-MIMO MAC supports link adaptation and is completely compatible with legacy stations. We evaluate the performance of the HT-MIMO MAC protocol and find that it outperforms the existing 802.11 MAC protocol with SU-MIMO and the downlink MU-MIMO MAC protocol in [9] with a remarkable throughput gains up to 86%. © 2012 Springer-Verlag.

关键词： MIMO systems

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Using NMFAS to identify key biological pathways associated with human diseases

Using NMFAS to identify key biological pathways associated w...

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2012 IEEE 6th International Conference on Systems Biology, ISB 2012

作者： Guo, Hao Zhu, Yunping Li, Dong He, Fuchu Liu, Qijun State Key Laboratory of Proteomics Beijing Proteome Research Centre Beijing Institute of Radiation Medicine Beijing China National Laboratory for Parallel and Distributed Processing National University of Deference and Technology Changsha China

ISBN: (纸本)9781467343985

Gene expression microarray enables us to measure the gene expression levels for thousands of genes at the same time. Here, we constructed the non-negative matrix factorization analysis strategy (NMFAS) to dig the underlying biological pathways related with various diseases by factorizing the pathway expression matrix, which was extracted from microarray matrix using pathway membership information, into the product of row and column vectors. We defined row vector as the pathway activity and column vector as the gene contribution weight. Via comparing the pathway activity of two different sample groups, we can identify significantly expressed pathways. We applied this strategy on two different cases: smoking and type 2 diabetes (DM2). We found 152 differentially expressed pathways by the comparison of pathway activity between smoker and never smoker, including pathways that have been validated in literature, such as "O-Glycans biosynthesis" and "Glutathione metabolism". We also found important genes related to smoking phenotype, such as NQO, HSPA1A, ALDH3A1. As for DM2 analysis, our results suggested 9 pathways were significantly expressed, including typical pathways like "Oxidative phosphorylation" and "mTOR signaling pathway", and found genes like CAPNS1, APP, COX7A1, COX7B, which might play important roles in the cellular regulations of DM2. In conclusion, Our strategy can be efficiently used to integrate gene expression profiles and biological pathway information to identify the key processes underlying human disease and can identify gene pathways missed by alternative approaches. © 2012 IEEE.

关键词： Non-negative matrix factorization

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Cooperative spectrum sharing in relay-trading mode: A fairness view

Cooperative spectrum sharing in relay-trading mode: A fairne...

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4th International Conference on Cyber-Enabled distributed Computing and Knowledge Discovery, CyberC 2012

作者： Liu, Lixia Hu, Gang Xu, Ming Peng, Yuxing National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China Department of Networks Engineering School of Computer National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9780769548104

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. © 2012 IEEE.

关键词： Cognitive radio

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