检索结果-内蒙古大学图书馆

Improved algorithm for reconstructing singular connection in multi-block CFD applications

Transactions of Nanjing University of Aeronautics and Astronautics 2013年第SUPPL.1期30卷 51-57页

作者： Wang, Yongxian Zhang, Lilun Che, Yonggang Xu, Chuanfu Liu, Wei Liu, Huayong Wang, Zhenghua College of Computer National University of Defense Technology Changsha 410073 China Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha 410073 China State Key Laboratory of Aerodynamics Mianyang 621000 China

An improved algorithm is proposed for the reconstruction of singular connectivity from the available pairwise connections during preprocessing phase. To evaluate the performance of the algorithm, an in-house computational fluid dynamics (CFD) code is used in which high-order finite-difference method for spatial discretization running on the Tianhe-1A supercomputer is employed. Test cases with a varied amount of mesh points are chosen, and the test results indicate that the improved singular connection reconstruction algorithm can achieve a speedup of 2000× at least when compared with the naive search method adopted in the former version of our code. Moreover, the parallel efficiency can benefit from the strategy of local communication based on the algorithm.

关键词： Finite difference method

来源：评论

学校读者我要写书评

暂无评论

Latency-Aware Dynamic Voltage and Frequency Scaling on Many-Core Architectures for Data-Intensive Applications

Latency-Aware Dynamic Voltage and Frequency Scaling on Many-...

引用

International Conference on Cloud computing and Big Data (CloudCom-Asia)

作者： Zhiquan Lai King Tin Lam Cho-Li Wang Jinshu Su Youliang Yan Wangbin Zhu National University of Defense Technology China The University of Hong Kong Hong Kong National Key Laboratory of Parallel and Distributed Processing (PDL) China Huawei Technologies Co. Ltd. Shenzhen China

Low power is the first-class design requirement for HPC systems. Dynamic voltage and frequency scaling (DVFS) has become the commonly used and efficient technology to achieve a trade-off between power consumption and system performance. However, most the prior work using DVFS did not take into account the latency of voltage/frequency scaling, which is a critical factor in real hardware determining the power efficiency of the power management algorithm. This paper, firstly, investigate the latency features of DVFS on a real many-core hardware platform. Secondly, we propose a latency-aware DVFS algorithm for profile-based power management to avoid aggressive power state transitions. At last, we evaluate our algorithm on Intel SCC platform using a data-intensive benchmark, Graph 500 benchmark. The experimental results not only show impressive potential for energy saving in data-intensive applications (up to 31% energy saving and 60% EDP reduction), but also evaluate the efficiency of our latency-aware DVFS algorithm which achieves 12.0% extra energy saving and 5.0% extra EDP reduction, moreover, increases the execution performance by 22.4%.

关键词： Benchmark testing Runtime Hardware Heuristic algorithms Time-frequency analysis Voltage measurement

来源：评论

学校读者我要写书评

暂无评论

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Speculative symbolic execution

Speculative symbolic execution

引用

2012 IEEE 23rd International Symposium on Software Reliability Engineering, ISSRE 2012

作者： Zhang, Yufeng Chen, Zhenbang Wang, Ji National Laboratory for Parallel and Distributed Processing Department of Computing Science National University of Defense Technology Changsha China

ISBN: (纸本)9780769548883

Symbolic execution is an effective path oriented and constraint based program analysis technique. Recently, there is a significant development in the research and application of symbolic execution. However, symbolic execution still suffers from the scalability problem in practice, especially when applied to large-scale or very complex programs. In this paper, we propose a new fashion of symbolic execution, named Speculative Symbolic Execution (SSE), to speed up symbolic execution by reducing the invocation times of constraint solver. In SSE, when encountering a branch statement, the search procedure may speculatively explore the branch without regard to the feasibility. Constraint solver is invoked only when the speculated branches are accumulated to a specified number. In addition, we present a key optimization technique that enhances SSE greatly. We have implemented SSE and the optimization technique on Symbolic Pathfinder (SPF). Experimental results on six programs show that, our method can reduce the invocation times of constraint solver by 20.7% to 48.7% (with an average of 29.9%), and save the search time from 23.6% to 43.6% (with an average of 30%). © 2012 IEEE.

关键词： Java programming language

来源：评论

学校读者我要写书评

暂无评论

Providing information services for wireless sensor networks through cloud computing

Providing information services for wireless sensor networks ...

引用

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

来源：评论

学校读者我要写书评

暂无评论

Research of context situation awareness technology

Research of context situation awareness technology

引用

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

来源：评论

学校读者我要写书评

暂无评论

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

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

引用

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)

来源：评论

学校读者我要写书评

暂无评论

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

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

引用

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)

来源：评论

学校读者我要写书评

暂无评论

The demand for consistent web-based workflow editors 8

The demand for consistent web-based workflow editors

引用

8th Workshop on Workflows in Support of Large-Scale Science, WORKS 2013

作者： Gesing, Sandra Atkinson, Malcolm Klampanos, Iraklis Galea, Michelle Berthold, Michael R. Barbera, Roberto Scardaci, Diego Terstyanszky, Gabor Kiss, Tamas Kacsuk, Peter University of Notre Dame Ctr for Research Computing University of Edinburgh Informatics Forum 111 Information Technology Center Notre DameIN46556 United States University of Edinburgh Informatics Forum EdinburghEH8 9AB United Kingdom Universität Konstanz FB Informatik and Informationswissenschaft Box 712 Konstanz78457 Germany Italian National Institute of Nuclear Physics Catania95123 Italy University of Westminster 115 New Cavendish Street LondonW1W 6UW United Kingdom Laboratory of Parallel and Distributed Systems MTA SZTAKI Kende Street 13-17 Budapest1111 Hungary

ISBN: (纸本)9781450325028

This paper identifies the high value to researchers in many disciplines of having web-based graphical editors for scientific workflows and draws attention to two technological transitions: good quality editors can now run in a browser and workflow enactment systems are emerging that manage multiple workflow languages and support multi-lingual workflows. We contend that this provides a unique opportunity to introduce multi-lingual graphical workflow editors which in turn would yield substantial benefits: workflow users would find it easier to share and combine methods encoded in multiple workflow languages, the common framework would stimulate conceptual convergence and increased workflow component sharing, and the many workflow communities could share a substantial part of the effort of delivering good quality graphical workflow editors in browsers. The paper examines whether such a common framework is feasible and presents an initial design for a web-based editor, tested with a preliminary prototype. It is not a fait accompli but rather an urgent rallying cry to explore collaboratively a generic web-based framework before investing in many divergent individual implementations.

关键词： Interoperability

来源：评论

学校读者我要写书评

暂无评论

Topology awareness algorithm for virtual network mapping

引用

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

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：