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IFIP/IEEE International Symposium on Integrated Network Management

作者： Zhihong Liu Qi Zhang Mohamed Faten Zhani Raouf Boutaba Yaping Liu Zhenghu Gong College of Computer National University of Defense Technology Changsha China David R. Cheriton School of Computer Science University of Waterloo Waterloo ON Canada Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9781479982424

MapReduce has become a popular model for large-scale data processing in recent years. However, existing MapRe-duce schedulers still suffer from an issue known as partitioning skew, where the output of map tasks is unevenly distributed among reduce tasks. In this paper, we present DREAMS, a framework that provides run-time partitioning skew mitigation. Unlike previous approaches that try to balance the workload of reducers by repartitioning the intermediate data assigned to each reduce task, in DREAMS we cope with partitioning skew by adjusting task run-time resource allocation. We show that our approach allows DREAMS to eliminate the overhead of data repartitioning. Through experiments using both real and synthetic workloads running on a 11-node virtual virtualised Hadoop cluster, we show that DREAMS can effectively mitigate negative impact of partitioning skew, thereby improving job performance by up to 20.3%.

关键词： Resource management Containers Predictive models Mathematical model Monitoring Biomedical monitoring Yarn

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Constraint-Relaxation Approach for Nonnegative Matrix Factorization: A Case Study

Constraint-Relaxation Approach for Nonnegative Matrix Factor...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Jue Wang Naiyang Guan Xuhui Huang Zhigang Luo Science and Technology on Parallel and Distributed Processing Laboratory College of Computer National University of Defense Technology Hunan P.R. China Department of Computer Science and Techonoly College of Computer National University of Defense Technology Hunan P.R. China

ISBN: (纸本)9781479986989

Nonnegative matrix factorization (NMF) is a powerful technique for dimensionality reduction. Conventional NMF algorithms usually keep the matrices W and H nonnegative while iterating. However, to get the NMF of a matrix, it's unnecessary to force the temporary solutions in iterations nonnegative. In this paper, we propose a two-staged approach for NMF. At the relaxation stage, the nonnegative constraint of temporary solutions is relaxed and a real valued matrix factorization is generated. At the constraint stage, the real valued matrix factorization is transformed to a nonnegative matrix factorization by an invertible linear transformation. Based on this approach, we study on exact nonnegative matrix factorization when rank=2. We proved that, given two real valued matrices of rank=2, there exists an invertible linear transformation which can transform the real valued matrices to nonnegative matrices with their product stable. We propose an algorithm to find out the transformation. When rank is higher than 2, this kind of transformation may not exist. In the experiments, it's showed that this approach can reach a nonnegative matrix factorization with lower reconstruction error than conventional methods, and the technique for rank=2 exact NMF works well.

关键词： Algorithm design and analysis Matrix decomposition Additives Computers Transforms Matrix converters Clustering algorithms

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Performance Optimization of a CFD Application on Intel Multicore and Manycore Architectures

Performance Optimization of a CFD Application on Intel Multi...

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10th Annual Conference of Advanced Computer Architecture, ACA 2014

作者： Che, Yonggang Zhang, Lilun Wang, Yongxian Xu, Chuanfu Liu, Wei Cheng, Xinghua Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha China

ISBN: (纸本)9783662444900

This paper reports our experience optimizing the performance of a high-order and high accurate Computational Fluid Dynamics (CFD) application (HOSTA) on the state of art multicore processor and the emerging Intel Many Integrated Core (MIC) coprocessor. We focus on effective loop vectorization and memory access optimization. A series techniques, including data structure transformations, procedure inlining, compiler SIMDization, OpenMP loop collapsing, and the use of Huge Pages, are explored. Detailed execution time and event counts from Performance Monitoring Units are measured. The results show that our optimizations have improved the performance of HOSTA by 1.61× on a two Intel Sandy Bridge processors based computer node and 1.97× on a Intel Knights Corner coprocessor, the public MIC product. The microarchitecture level effects of these optimizations are also discussed. © Springer-Verlag Berlin Heidelberg 2014.

关键词： Computational fluid dynamics

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High-energy-density electron beam from interaction of two successive laser pulses with subcritical-density plasma

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Physical Review Accelerators and Beams 2016年第2期19卷 021301-021301页

作者： J. W. Wang W. Yu M. Y. Yu H. Xu J. J. Ju S. X. Luan M. Murakami M. Zepf S. Rykovanov Helmholtz Institute Jena Jena 07743 Germany State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 China Institute for Fusion Theory and Simulation and the Department of Physics Zhejiang University Hangzhou 310027 China Institute for Theoretical Physics I Ruhr University Bochum D-44780 Germany National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha 410073 China Institute of Laser Engineering Osaka University Osaka 565-0871 Japan Centre for Plasma Physics School of Mathematics and Physics Queen’s University Belfast Belfast BT7 1NN United Kingdom

It is shown by particle-in-cell simulations that a narrow electron beam with high energy and charge density can be generated in a subcritical-density plasma by two consecutive laser pulses. Although the first laser pulse dissipates rapidly, the second pulse can propagate for a long distance in the thin wake channel created by the first pulse and can further accelerate the preaccelerated electrons therein. Given that the second pulse also self-focuses, the resulting electron beam has a narrow waist and high charge and energy densities. Such beams are useful for enhancing the target-back space-charge field in target normal sheath acceleration of ions and bremsstrahlung sources, among others.

关键词： Plasma acceleration & new acceleration techniques

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Completion time-a ware flow scheduling in heterogenous networks 1

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15th International Conference on Algorithms and Architectures for Parallel processing, ICA3PP 2015

作者： He, Shiming Xie, Kun Zhang, Dafang Hunan Provincial Key Laboratory of Intelligent Processing of Big Data on Transportation School of Computer and Communication Engineering Hunan Province Engineering Research Center of Electric Transportation and Smart Distributed Network Changsha University of Science and Technology Changsha410114 China College of Computer Science and Electronics Engineering Hunan University Changsha410082 China Department of Electrical and Computer Engineering State University of New York at Stony Brook NY United States

ISBN: (数字)9783319271194

ISBN: (纸本)9783319271187

In China, the expressway isn’t free. When a vehicle exits, the exit toll station needs to calculate the toll according to the vehicle trajectory obtained by sending a trajectory query task to the trajectory center remotely. For the accurate of toll and keep the exit smoothly, transmitting the trajectory result reliably and in time is a key issue. There are three heterogenous networks in expressway, Fibernet, Telecommunications Network and 3G. We concurrently exploit three heterogenous networks by allocating the trajectory result into three sub-flows where each sub-flow is transmitted in one kind of networks. But existing multipath transfer solution(FMTCP) doesn’t consider the difference of completed time among all sub-flows and can’t make sure the completed time in time. Therefore, we formulate the sub-flows schedule as a integer programming problem, which is proved to be NP-hard problem, and propose a Completion time-aware Flow Scheduling scheme (CaFS) which calculates the size of sub-flows. For the reliably, it exploits generation-based network coding. For the transmission in time, CaFS allocates the size of sub-flow into suitable generation and scheduling the generations. The simulation results demonstrate that, comparing with the FMTCP, CaFS improves 31. 9% in completion time and 30% in task finished rate. © Springer International Publishing Switzerland 2015.

关键词： Network coding

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NVLAN: A Novel VLAN technology for Scalable Multi-tenant Datacenter Networks 2

NVLAN: A Novel VLAN Technology for Scalable Multi-tenant Dat...

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2nd International Conference on Advanced Cloud and Big Data, CBD 2014

作者： Hu, Yang Li, Huiba Peng, Yuxing Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Computer Science Department China

ISBN: (纸本)9781479980857

Nowadays, cloud providers of 'Infrastructure as a service' require datacenter networks to support virtualization and multi-tenancy at large scale, while it brings a grand challenge to datacenters. Traditional network technologies of datacenters and common commodity devices of network can not meet these new needs. In this paper, we present NVLAN, a novel VLAN technology for scalable multi-tenant datacenter networks. NVLAN eliminates the quantity limitation of logic isolated networks on VLAN through a slight modification. NVLAN can be applied to very large-scale datacenter networks, without the need of expensive and dedicated switches. Through encapsulation of tenant's packets, NVLAN provides tenants with full address space virtualization to configure their own logic network. We implemented NVLAN on a test bed, and demonstrated that it can be scaled up to large numbers of multi-tenant networks with negligible overhead. © 2014 IEEE.

关键词： Virtualization

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Merge-Weighted Dynamic Time Warping for Speech Recognition

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Journal of Computer science & technology 2014年第6期29卷 1072-1082页

作者：张湘莉兰骆志刚李明 State Key Laboratory of Pathogen and Biosecurity Beijing Institute of Microbiology and Epidemiology Science and Technology on Parallel and Distributed Processing Laboratory School of Computer Science National University of Defense Technology David R.Cheriton School of Computer Science University of WaterlooWaterlooOntario N2L 3G1Canada ACM IEEE

Obtaining training material for rarely used English words and common given names from countries where English is not spoken is difficult due to excessive time, storage and cost factors. By considering personal privacy, language- independent （LI） with lightweight speaker-dependent （SD） automatic speech recognition （ASR） is a convenient option to solve tile problem. The dynamic time warping （DTW） algorithm is the state-of-the-art algorithm for small-footprint SD ASR for real-time applications with limited storage and small vocabularies. These applications include voice dialing on mobile devices, menu-driven recognition, and voice control on vehicles and robotics. However, traditional DTW has several lhnitations, such as high computational complexity, constraint induced coarse approximation, and inaccuracy problems. In this paper, we introduce the merge-weighted dynamic time warping （MWDTW） algorithm. This method defines a template confidence index for measuring the similarity between merged training data and testing data, while following the core DTW process. MWDTW is simple, efficient, and easy to implement. With extensive experiments on three representative SD speech recognition datasets, we demonstrate that our method outperforms DTW, DTW on merged speech data, the hidden Markov model （HMM） significantly, and is also six times faster than DTW overall.

关键词： merge-weighted dynamic time warping natural language processing speech recognition and synthesis tem-plate confidence index

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RTC: Link schedule based MAC design in multi-hop wireless network

RTC: Link schedule based MAC design in multi-hop wireless ne...

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International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE)

作者： Xuan Dong Yinjia Huo Chunsheng Zhu Shaohe Lv Wenxiang Li Xiaodong Wang Department of Electrical and Computer Engineering The University of British Columbia Vancouver BC Canada National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China Engineering Research Center for Metallurgical Automation and Detecting Technology of Ministry of Education Wuhan University of Science and Technology Wuhan China

ISBN: (纸本)9781479982172

The performance of an ad-hoc network is greatly limited by collisions due to hidden terminals. In this paper, we propose a receiver tracking contention (RTC) scheme, which achieves high throughput by allowing the receivers to assist for channel contention. In RTC, link is the basic unit for channel access contention. Specifically, transmitter is used to contend for the channel and receiver is used to announce the potential collision. Based on INT message coding scheme, transmitter and its corresponding receiver can be well coordinated. In such mechanism, hidden terminals are avoided and exposed terminals are encouraged to transmit simultaneously. Based on OFDM modulation, RTC packets several subcarriers as subcontention unit and operates channel contention over multiple subcontention units. Furthermore, each subcontention unit maintains a transmission set, where collision-free links are allowed to merged into the transmission set In this case, the transmission set of subcontention unit can be aggregated after each contention period. When the subcontention unit i is the smallest index of non-empty subcontention unit, the transmission set of unit i will win the channel contention and transmitters of unit i will start to transmit in the following data transmission period. Analysis and simulation results show that RTC achieves a notable throughput gain over Back2f as high as 190% through simulation.

关键词： Receivers OFDM Transmitters Electronics packaging

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Symmetric Non-negative Matrix Factorization Based Link Partition Method for Overlapping Community Detection

Symmetric Non-negative Matrix Factorization Based Link Parti...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Xiang Zhang Naiyang Guan Wenju Zhang Xuhui Huang Shuyi Wu Zhigang Luo Science and Technology on Parallel and Distributed Processing Laboratory College of Computer National University of Defense Technology Hunan P.R. China Institute of Software College of Computer National University of Defense Technology Hunan P.R. China Department of Computer Science and Technology College of Computer National University of Defense Technology Hunan P.R. China

ISBN: (纸本)9781479986989

Partitioning links rather than nodes is effective in overlapping community detection (OCD) on complex networks. However, it consumes high CPU and memory overheads because the volume of links is huge especially when the network is rather complex. In this paper, we proposes a symmetric non-negative matrix factorization (SNMF) based link partition method called SNMF-Link to overcome this deficiency. In particular, SNMF-Link represents data in a lower-dimensional space spanned by the node-link incidence matrix. By solving a lighter SNMF problem, SNMF-Link learns the clustering indicators of each links. Since traditional multiplicative update rule (MUR) based optimization algorithm for SNMF suffers from slow convergence, we applied the augmented Lagrangian method (ALM) to efficiently optimize SNMF. Experimental results show that SNMF-Link is much more efficient than the representative clustering algorithms without reducing the OCD performance.

关键词： Symmetric matrices Convergence Optimization Partitioning algorithms Chlorine Complex networks Image edge detection

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Exploring the patterns of social behavior in Github 1

Exploring the patterns of social behavior in Github

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1st International Workshop on Crowd-Based Software Development Methods and Technologies, CrowdSoft 2014

作者： Yu, Yue Yin, Gang Wang, Huaimin Wang, Tao National Laboratory for Parallel and Distributed Processing School of Computer Science National University of Defense Technology Changsha410073 China

ISBN: (纸本)9781450332248

Social coding paradigm is reshaping the distributed soft- ware development with a surprising speed in recent years. Github, a remarkable social coding community, attracts a huge number of developers in a short time. Various kinds of social networks are formed based on social activities among developers. Why this new paradigm can achieve such a great success in attracting external developers, and how they are connected in such a massive community, are interesting questions for revealing power of social coding paradigm. In this paper, we firstly compare the growth curves of project and user in GitHub with three traditional open source software communities to explore differences of their growth modes. We find an explosive growth of the users in GitHub and introduce the Diffusion of Innovation theory to illustrate intrinsic sociological basis of this phenomenon. Secondly, we construct follow-networks according to the follow behaviors among developers in GitHub. Finally, we present four typical social behavior patterns by mining follow-networks containing independence-pattern, group-pattern, star-pattern and hub-pattern. This study can provide several instructions of crowd collaboration to newcomers. According to the typical behavior patterns, the community manager could design corresponding assistive tools for developers. Copyright 2014 ACM.

关键词： Software design

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