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IEEE International Conference on Cloud Computing Technology and science (CloudCom)

作者： Shadi Ibrahim Hai Jin Lu Lu Song Wu Bingsheng He Li Qi Cluster and Grid Computing Laboratory Services Computing Technology and System Laboratory Huazhong University of Science and Technology Wuhan China School of Computer Engineering Nanyang Technological University Singapore Information and Technology Department China Development Bank Beijing China

This paper investigates the problem of Partitioning Skew in MapReduce-based system. Our studies with Hadoop, a widely used MapReduce implementation, demonstrate that the presence of partitioning skew causes a huge amount of data transfer during the shuffle phase and leads to significant unfairness on the reduce input among different data nodes. As a result, the applications experience performance degradation due to the long data transfer during the shuffle phase along with the computation skew, particularly in reduce phase. We develop a novel algorithm named LEEN for locality-aware and fairness-aware key partitioning in MapReduce. LEEN embraces an asynchronous map and reduce scheme. All buffered intermediate keys are partitioned according to their frequencies and the fairness of the expected data distribution after the shuffle phase. We have integrated LEEN into Hadoop-0.18.0. Our experiments demonstrate that LEEN can efficiently achieve higher locality and reduce the amount of shuffled data. More importantly, LEEN guarantees fair distribution of the reduce inputs. As a result, LEEN achieves a performance improvement of up to 40% on different workloads.

关键词： Partitioning algorithms Distributed databases Cloud computing Performance evaluation Time factors Degradation Kernel

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All-optical wavelength conversion based on four-wave mixing in silicon waveguides

All-optical wavelength conversion based on four-wave mixing ...

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9th International Conference on Optical Communications and Networks (ICOCN 2010)

作者： Shiming Gao Zhiqiang Li Yanqiao Xie Qiang Liu Xingzhi Zhang Yaocheng Shi Sailing He En-Kuang Tien Ozdal Boyraz Centre for Optical Electromagnetic Research State Key Laboratory of Modern Optical Instrumentation University of Zhejiang Hangzhou China Advanced Photonics Device and System Laboratory Department of Electrical Engineering and Computer Science University of California Irvine Irvine CA USA

All-optical wavelength conversion is investigated using four wave mixing in silicon waveguides. The influences of nonlinear losses caused by two-photon absorption (TPA) and TPA-induced free-carrier absorption on the conversion efficiency and phase-matching condition are analyzed. The conversion bandwidth is tempted to enhance by optimizing the waveguide geometry and using the two-pump regime. And finally an angled-polarization pump is used to realize the polarization-independent wavelength conversion by eliminating the polarization discrepancy between the TE and TM modes.

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Quality multi-domain meshing for volumetric data

Quality multi-domain meshing for volumetric data

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International Conference on BioMedical engineering and Informatics (BMEI)

作者： Qin Zhang Bharadwaj Subramanian Guoliang Xu Chandrajit L. Bajaj CVC Institute for Computational Engineering and Sciences University of Technology Austin TX USA Institute of Computational Mathematics Academy of Mathematics and System Sciences Chinese Academy and Sciences Beijing China CVC Institute for Computational Engineering and Sciences Department of Computer Science University of Technology Austin TX USA

Multi-domain meshing from volumetric data is of great importance in many fields like medicine, biology and geology. This paper proposes a new approach to produce a high quality mesh with separated multiple domains. A point cloud is generated from a preliminary mesh representing the boundary between different domains from the discrete volumetric representation used as input. A higher-order level-set method is employed to produce a quality sub-mesh from this point cloud and geometric flow is used as smoothing mechanism. A new approach to detect and curate intersections within an assembly of these 2-manifold sub-meshes by utilizing the intermediate volumetric representation is developed. The separation between sub-meshes can be controlled by the user using a gap threshold parameter. The resulting high quality multi-domain mesh is free from self- and inter-domain intersections and can be further utilized in finite element and boundary element computations. The proposed pipeline has been efficiently implemented and sample meshes have been provided for visualization.

关键词： Surface reconstruction Pipelines Clouds Smoothing methods Isosurfaces Three dimensional displays Image reconstruction

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4D respiratory motion-corrected Rb-82 myocardial perfusion PET image reconstruction

4D respiratory motion-corrected Rb-82 myocardial perfusion P...

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IEEE Symposium on Nuclear science (NSS/MIC)

作者： Arman Rahmim Jing Tang M. R. Ay F. M. Bengel Department of Radiology and the Department of Electrical and Computer Engineering Johns Hopkins University Baltimore MD USA Division of Imaging Physics and System Analysis Philips Healthcare Cleveland OH USA Research Center of Science and Technology Department of Medical Physics and Biomedical Engineering Tehran University of Medical Sciences Tehran Iran Department of Radiology Johns Hopkins University Baltimore MD USA

Routine clinical myocardial perfusion (MP) PET imaging involves the use of cardiac gating only. Nonetheless, respiratory motion of the heart can considerably degrade the quality of MP images and the quantitative accuracy of myocardial uptake estimates. We first performed a quantitative evaluation of the degrading contributions of cardiac (C) and respiratory (R) motion, as well as non-motion factors of Rb-82 positron range, photon non-collinearity, crystal scattering and penetration. For a normal human simulated phantom, we showed that the combination of all above factors resulted in -48% underestimation of myocardial activity, while corrections for all non-motion factors resulted in 21%, 36% and 41% underestimated myocardial activities in the presence of C, R and C&R motion. This means that compensation for respiratory motion must be considered as critical towards achieving overall motion compensation and/or resolution modeling. To achieve respiratory motion compensation, we used translation motion vectors to first match respiratory-only gated images to the end-expiration reference frame. Next, for each cardiac gate, a 4D EM reconstruction algorithm was applied to the R-gated data within that cardiac phase. Three techniques were compared involving reconstructions of (a) a single R-gate only, and all R-gates (b) without and (c) with respiratory motion correction (MC). Using simulated PET data, quantitative comparisons of noise vs. bias trace-off curves indicated notable improvements for the proposed 4D respiratory MC method. Using CHO analysis as applied to the task of perfusion defect detection, ROC analysis of the three methods resulted in AUC values of 0.610±0.039, 0.645±0.038 and 0.821±0.029. The CLABROC statistical test revealed that the proposed MC technique significantly outperformed the other two methods in the task of defect detection.

关键词： Positron emission tomography Logic gates Image reconstruction Myocardium Computed tomography Heart

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Research of geometric computing and its theory

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Shanghai Jiaotong Daxue Xuebao/Journal of Shanghai Jiaotong University 2010年第3期44卷 407-412页

作者： He, Yuan-Jun Department of Computer Science and Engineering MOE-Microsoft Key Laboratory for Intelligent Computing and Intelligent System Shanghai Jiaotong University Shanghai 200240 China

A new geometric computing theory was proposed. On the definition level of geometric elements, using the Cartesian coordinates ideology as reference, 2D and 3D ″geometric algebra elements″ (or ″geometric elements″ for short, which could construct an upper-level element in the solving sequence) were constructed by geometry algebraization methods. On the processing level of geometries, geometric problems were solved with geometry methods, by which a geometric element solving sequence could be constructed. Directional property was introduced into geometries in this theory and geometries were represented in a unified format. They help to simplify the processing of finding the geometric element solving sequence for a geometry problem. The paper also tried to theoretically find out an integrated solution for geometry ambiguity issues, and established a unified, standardized geometry computing architecture. The Leibniz's mind-to process geometric objects with geometric language-was implemented in an indirect way!

关键词： Geometry

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Monte Carlo analysis of a low power domino gate under parameter fluctuation

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Journal of Semiconductors 2009年第12期30卷 113-117页

作者：汪金辉吴武臣宫娜侯立刚彭晓宏高大明 VLSI and System Laboratory Beijing University of Technology Department of Computer Science and Engineering State University of New York at Buffalo

Using the multiple-parameter Monte Carlo method, the effectiveness of the dual threshold voltage technique （DTV） in low power domino logic design is analyzed. Simulation results indicate that under significant temperature and process fluctuations, DTV is still highly effective in reducing the total leakage and active power consumption for domino gates with speed loss. Also, regarding power and delay characteristics, different structure domino gates with DTV have different robustness against temperature and process fluctuation.

关键词： domino gate temperature and process fluctuation effectiveness

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Optimal Control of Affine Nonlinear Continuous-time systems Using an Online Hamilton-Jacobi-Isaacs Formulation

Optimal Control of Affine Nonlinear Continuous-time Systems ...

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2010 49th IEEE Conference on Decision and Control

作者： T. Dierks S. Jagannathan DRS Sustainment System Inc. 201 Evans Lane St. Louis MO 63121 Department of Electrical and Computer Engineering Missouri University of Science and Technology 301 W. 16th St. Rolla MO 65409

ISBN: (纸本)9781424477456

Solving the Hamilton-Jacobi-Isaacs (HJI) equation, commonly used in H_(infinity) optimal control, is often referred to as a two-player differential game where one player tries to minimize the cost function while the other tries to maximize it. In this paper, the HJI equation is formulated online and forward-in-time using a novel single online approximator (SOLA)-based scheme to achieve optimal regulation and tracking control of affine nonlinear continuous-time systems. The SOLA-based adaptive approach is designed to learn the infinite horizon HJI equation, the corresponding optimal control input, and the worst case disturbance. A novel parameter tuning algorithm is derived which not only achieves the optimal cost function, control input, and the disturbance, but also ensures the system states remain bounded during the online learning. Lyapunov methods are used to show that all signals are uniformly ultimately bounded (UUB) while ensuring the approximated signals approach their optimal values with small bounded error. In the absence of OLA reconstruction errors, asymptotic convergence to the optimal signals is demonstrated, and simulation results illustrate the effectiveness of the approach.

关键词： Optimal control Cost functions Continuous time systems Affine In-law Lyapunov methods signals control input tracking control Bounded disturbance trees (mathematics)

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Four-level superradiant laser with full atomic cooperativity

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Physical Review A 2010年第5期81卷 053809-053809页

作者： Deshui Yu Jingbiao Chen Department of Applied Physics Graduate School of Engineering The University of Tokyo Bunkyo-ku Tokyo 113-8656 Japan Institute of Quantum Electronics and State Key Laboratory of Advanced Optical Communication System & Network School of Electronics Engineering & Computer Science Peking University Beijing 100871 People's Republic of China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai 200062 People's Republic of China

We investigate a four-level superradiant laser whose intensity is proportional to N2 and whose linewidth scales as 1/N2. In the absence of spontaneous emissions, we derive the stationary solutions of the atomic full cooperativity, analyze their stabilities, and find the corresponding irreducible representation based on group U(4). We also investigate the spectra of the phase and amplitude fluctuations of the fields inside and outside the cavity and find that the amplitude fluctuations of the output fields cannot be squeezed in the low-frequency limit, which is completely different from the three-level superradiant laser system. Finally, we consider the stationary solutions corresponding to the partial cooperativity due to the symmetry breaking of U(4) induced by the atomic spontaneous emissions.

关键词： Spontaneous emission

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New features of Easy Java Simulations for 3D Modeling

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IFAC Proceedings Volumes 2010年第24期42卷 250-255页

作者： Carlos A. Jara Francisco Esquembre Francisco A. Candelas Fernando Torres Sebastián Dormido Department of Physics System Engineering and Signal Theory University of Alicante Alicante Spain (e-mail:{carlos.jara francisco.candelas fernando.torres}@ua.es) Department of Mathematics University of Murcia Murcia Spain (e-mail: fem@um.es) Department of Computer Science and Automatic Control UNED University Madrid Spain (e-mail: sdormido@dia.uned.es)

This paper presents a new interface framework which has been added to Easy Java Simualtions' environment in order to improve its graphical features for 3D modeling. These new 3D capabilities provide users a set of new view elements which can be used to develop models with a high degree of reality. In this way, Easy Java Simulations becomes a powerful tool to easily and quickly create 3D realistic simulations.

关键词： computer simulation modeling programming environment software tool virtual reality

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Movement Persuit Control of an Offshore Automated Platform via a RAM-based Neural Network

Movement Persuit Control of an Offshore Automated Platform v...

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International Conference on Control, Automation, Robotics and Vision

作者： Horacio L. Franca Joao Carlos P. da Silva Omar Lengerke Max S. Dutra Massimo De Gregorio Felipe M. G. Franca Computer Science Department Mathematics Institute Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Mechanical Engineering Program COPPE Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Istituto di Cibernetica "Eduardo Caianiello" Consiglio Nazionale delle Ricerche (CNR) Naples Italy System Engineering and Computer Science Program COPPE Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil

ISBN: (纸本)9781424478149

The reproduction of the movements of a ship by automated platforms, without the use of sensors providing exact data related to the numeric variables involved, is a non-trivial matter. The creation of an artificial vision system that can follow the cadence of said ship, in six axes of freedom, is the goal of this research. Considering that a real time response is a requisite in this case, it was decided to adopt a Boolean artificial neural network system that could identify and follow arbitrary interest points that could define, as a group, a model of the movement of an observed vessel. This paper describes the development of a prototype based on the Boolean perceptron model WiSARD (Wilkie, Stonham and Aleksander's Recognition Device), that is being implemented in the C programming language on a desktop computer using a regular webcam as input.

关键词： Stewart platform weightless neural networks WiSARD

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