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International Conference on Computer science and Network technology

作者： Yaodan Mai Long Lan Naiyang Guan Xiang Zhang Zhigang Luo College of Computer National University of Defense Technology Changsha 410073 China National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9781467381741

Nonnegative matrix factorization (NMF) is an effective speech separation approach of extracting discriminative components of different speaker. However, traditional NMF focuses only on the additive combination of the components and ignores the dependencies of speeches. Convolutive NMF (CNMF) captures the dependencies of speeches by overlapping components and achieves better separation performance. NMF and CNMF learn dictionaries for speakers in the absence of mixture, and thus they are unable to get enough information to learn dictionaries accurately when testing speeches are available. To handle this problem, transductive NMF (TNMF) is proposed which simultaneously utilizes speech of each speaker and mixture to learn more meaningful features of speakers, and significantly boost speech separation. CNMF addresses the dependencies of speech signals while it ignores the positive effect of mixtures in learning dictionaries. TNMF emphasizes the transductive learning of dictionaries while it fails to consider dependencies of speeches. This paper proposes transductive convolutive NMF (TCNMF) to overcome the deficiencies of both CNMF and TNMF. Experimental results show that our method makes significant improvement compared to aforementioned NMFbased methods.

关键词： Nonnegative matrix factorization single-channel speech separation transductive convolutive dictionary learning speech separation Speech matrix decomposition Loudspeakers Dictionaries as Topic NMF protocol Nonnegative mixtures DEPENDENCE

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Design and Implementation of a Highly Efficient DGEMM for 64-Bit ARMv8 Multi-core Processors

Design and Implementation of a Highly Efficient DGEMM for 64...

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International Conference on parallel processing (ICPP)

作者： Feng Wang Hao Jiang Ke Zuo Xing Su Jingling Xue Canqun Yang School of Computer Science National University of Defense Technology Changsha China School of Computer Science and Engineering University of New South Wales NSW Australia Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha China

This paper presents the design and implementation of a highly efficient Double-precision General Matrix Multiplication (DGEMM) based on Open BLAS for 64-bit ARMv8 eight-core processors. We adopt a theory-guided approach by first developing a performance model for this architecture and then using it to guide our exploration. The key enabler for a highly efficient DGEMM is a highly-optimized inner kernel GEBP developed in assembly language. We have obtained GEBP by (1) maximizing its compute-to-memory access ratios across all levels of the memory hierarchy in the ARMv8 architecture with its performance-critical block sizes being determined analytically, and (2) optimizing its computations through exploiting loop unrolling, instruction scheduling and software-implemented register rotation and taking advantage of A64 instructions to support efficient FMA operations, data transfers and prefetching. We have compared our DGEMM implemented in Open BLAS with another implemented in ATLAS (also in terms of a highly-optimized GEBP in assembly). Our implementation outperforms the one in ALTAS by improving the peak performance (efficiency) of DGEMM from 3.88 Gflops (80.9%) to 4.19 Gflops (87.2%) on one core and from 30.4 Gflops (79.2%) to 32.7 Gflops (85.3%) on eight cores. These results translate into substantial performance (efficiency) improvements by 7.79% on one core and 7.70% on eight cores. In addition, the efficiency of our implementation on one core is very close to the theoretical upper bound 91.5% obtained from micro-benchmarking. Our parallel implementation achieves good performance and scalability under varying thread counts across a range of matrix sizes evaluated.

关键词： Registers Kernel Computational modeling Program processors Assembly Memory management

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Iaso： an autonomous fault-tolerant management system for supercomputers

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Frontiers of Computer science 2014年第3期8卷 378-390页

作者： Kai LU Xiaoping WANG Gen LI Ruibo WANG Wanqing CHI Yongpeng LIU Hongwei TANG Hua FENG Yinghui GAO Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha 410073 China College of Computer National University of Defense Technology Changsha 410073 China ATR Laboratory National University of Defense Technology Changsha 410073 China

With the increase of system scale, the inherent reliability of supercomputers becomes lower and lower. The cost of fault handling and task recovery increases so rapidly that the reliability issue will soon harm the usability of supercomputers. This issue is referred to as the ＂reliability wall＂, which is regarded as a critical problem for current and future supercomputers. To address this problem, we propose an autonomous fault-tolerant system, named Iaso, in MilkyWay- 2 system. Iaso introduces the concept of autonomous management in supercomputers. By autonomous management, the computer itself, rather than manpower, takes charge of the fault management work. Iaso automatically manage the whole lifecycle of faults, including fault detection, fault diagnosis, fault isolation, and task recovery. Iaso endows the autonomous features with MilkyWay-2 system, such as self-awareness, self-diagnosis, self-healing, and self-protection. With the help of Iaso, the cost of fault handling in supercomputers reduces from several hours to a few seconds. Iaso greatly improves the usability and reliability of MilkyWay-2 system.

关键词： supercomputer autonomous management fault tolerant fault management MilkyWay-2 system

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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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Mirror image:newfangled cell-level layout technique for single-event transient mitigation

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Chinese science Bulletin 2014年第23期59卷 2850-2858页

作者： Pengcheng Huang Shuming Chen Zhengfa Liang Jianjun Chen Chunmei Hu Yibai He Micro-electronics and Microprocessor Institute National University of Defense Technology National Laboratory for Parallel and Distributed Processing National University of Defense Technology

Recent years,the hardening of combinational circuits is becoming a common *** the transistor-level hardening technique,the cell-level hardening technique,a divide and conquer strategy,can substantially make use of some typical character in the cell-circuit module to mitigate single event transient(SET)*** mirror image(MI)technique proposed in this paper can adequately enhance the charge sharing in those cell-circuits with stage-by-stage inverter-like structure.3D TCAD mixed-mode simulation have been performed in 65 nm twinwell bulk CMOS process,the results indicate that the MI technique can almost reduce the SET pulse width from the anterior-stage PMOS over 25%,and can mitigate the SET pulse width from the posterior-stage PMOS about 10%.The MI technique,a represent of the cell-level technique,may be the future of the hardening of combinational circuits.

关键词：单事件技术细胞瞬态镜像组合逻辑电路次布 CMOS工艺

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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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Maximizing the information diffusion opportunity in the cyber-physical network

Maximizing the information diffusion opportunity in the cybe...

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

作者： Hongliang Lu Xuan Dong Wenxiang Li Saohe Lv Xiaodong Wang Wei Chen Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Hunan China School of Information Science and Engineering Wuhan University of Science and Technology Wuhan 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

Our daily life is changing by the smart objects, such as smart watches, smart phones etc. They make the cyber world and the physical world integrated by their abundant abilities of sensing, communication and computation etc. Focusing on a wide range of the integrated network, a statistical based strategy was introduced to get a special kind of link between objects, the statistical probability communication link. To get a maximized information spread probability for grouped people, this paper introduced a distributed, yet efficient algorithm naming DMPID algorithm, for finding a sub-network to spread people oriented inforamtion. The DMPID algorithm take the size of the selection and the information spread probability into account, and made a balance between the two parameters. Extended simulation showed that the DMPID algorithm performs well in different distributed networks.

关键词： distributed algorithms probability statistical analysis telecommunication networks DMPID algorithm cyber world cyber-physical network distributed maximizing probability of information diffusion information diffusion opportunity information spread probability statistical probability communication link

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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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DREAMS: Dynamic resource allocation for MapReduce with data skew

DREAMS: Dynamic resource allocation for MapReduce with data ...

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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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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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