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Investigating manifold learning algorithms based on magnification factors and principal spread directions

Jisuanji Xuebao/Chinese Journal of Computers 2005年第12期28卷 2000-2009页

作者： He, Li Zhang, Jun-Ping Zhou, Zhi-Hua Shanghai Key Laboratory of Intelligent Information Processing Department of Computer Science and Engineering Fudan University Shanghai 200433 China Key Laboratory of Complex Systems and Intelligence Science Chinese Academy of Sciences Shanghai 200433 China Department of Computer Science and Engineering School of Mathematical Sciences Fudan University Shanghai 200433 China National Laboratory for Novel Software Technology Nanjing University Nanjing 210093 China

As a new unsupervised learning technique, manifold learning has captured the attention of many researchers in the field of machine learning and cognitive sciences. The major algorithms include Isometric mapping (ISOMAP) and Locally Linear Embedding (LLE). The approaches can be used for discovering the intrinsic dimensions of nonlinear high-dimensional data effectively and aim researchers to analyze the data better. How to quantitatively analyze the relationship between the intrinsic dimensions and the observation space, however, has fewer reports. And thus further works in manifold learning may have suffered some difficulties. The paper focuses on two kinds of manifold learning algorithms (ISOMAP, LLE), and discusses magnification factors and principal spread directions from the observation space to the intrinsic low-dimensional space. Also the corresponding algorithm is proposed. Experiments show the effectiveness and advantages of the research.

关键词： Learning algorithms

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Effect of periodic disturbance to the hierarchical structure in turbulent boundary layer

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Beijing Daxue Xuebao (Ziran Kexue Ban)/Acta Scientiarum Naturalium Universitatis Pekinensis 2005年第5期41卷 688-694页

作者： Cheng, Xueling Hu, Fei State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Science Beijing 100029 China State Key laboratory for Turbulence and Complex System Department of Mechanical and Engineering Science Peking University Beijing 100871 China

Artificial periodic disturbances are introduced to the outer field of turbulent boundary layer in an closed-circuit open water channel. Statistical method is employed for analyzing the velocity-fluctuation-time-series. The effect of the disturbance to turbulent structure in boundary layer is studied. The result indicates the She-Leveque hierarchical similarity exists among high frequency turbulence.

关键词： Hierarchical structure Periodic vibration Scaling law Turbulence

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Numerical Solution of Lock-Release Gravity Current with Viscous Self-Similar Regime

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海洋工程：英文版 2004年第1期18卷 157-162页

作者：张立柱李行伟陈国谦 Department of Mechanics and Engineering Science/State Key Laboratory for Turbulence and Complex System Department of Civil Engineering

Lock-release gravity currents with a viscous self-similar regime are simulated by use of the renormalization group (RNG) k-ε model for Reynolds-stress closure. Besides the turbulent regime with initially a slumping phase of a constant current front speed and later an inviscid self-similar phase of front speed decreasing as t -1/3 (where t is the time measured from release), the viscous self-similar regime is satisfactorily reproduced with front speed decreasing as t -4/5, consistent with well known experimental observations.

关键词： gravity current self-similarity turbulence modeling environmental fluid mechanics

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DECAY OF VORTEX VELOCITY AND DIFFUSION OF TEMPERATURE IN A GENERALIZED SECOND GRADE FLUID

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Applied Mathematics and Mechanics(English Edition) 2004年第10期25卷 1151-1159页

作者：沈芳谭文长赵耀华 T.增冈隆士 Department of Mechanics and Engineering Science State Key Laboratory for Turbulence and Complex System Research Peking University Institute of Engineering Thermophysics Chinese Academy of Sciences Department of Mechanical Engineering Science Kyushu University

The fractional calculus approach in the constitutive relationship model of viscoelastic fluid was introduced. The velocity and temperature fields of the vortex flow of a generalized second fluid with fractional derivative model were described by fractional partial differential equations. Exact analytical solutions of these differential equations were obtained by using the discrete Laplace transform of the sequential fractional derivatives and generalized Mittag-Leffler function. The influence of fractional coefficient on the decay of vortex velocity and diffusion of temperature was also analyzed.

关键词： generalized second grade fluid fractional calculus unsteady flow temperature field generalized Mittag-Leffler function

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UNSTEADY FLOWS OF A GENERALIZED SECOND GRADE FLUID WITH THE FRACTIONAL DERIVATIVE MODEL BETWEEN TWO PARALLEL PLATES

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Acta Mechanica Sinica 2004年第5期20卷 471-476页

作者：谭文长徐明喻 1 Department of Mechanics and Engineering Science & State Key Laboratory for Turbulence and Complex System Research Peking UniversityBeijing 100871China Institute of Mathematics and Systematical Science Shandong UniversityJinan 250100China

The fractional calculus approach in the constitutive relationship model of a generalized second grade fluid is *** analytical solutions are obtained for a class of unsteady flows for the generalized second grade fluid with the fractional derivative model between two parallel plates by using the Laplace transform and Fourier transform for fractional *** unsteady flows are generated by the impulsive motion or periodic oscillation of one of the *** addition,the solutions of the shear stresses at the plates are also determined.

关键词： fractional derivative unsteady flows generalized second grade fluid parallel plates

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Teracluster LSSC-II--Its designing principles and applications in large scale numerical simulations

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中国科学A辑（英文版） 2004年第z1期47卷 53-68页

作者： Zhang Linbo Chen Shiyi LI Xinliang CAO Jianwen ZHANG Wensheng GONG Xingao State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China Department of Mechanical Engineering The Johns Hopkins University and Center for Computational Science and Engineering Peking University Beijing 100875 China Institute of Mechanics Chinese Academy of SciencesBeijing 100080 China Parallel Computing Laboratory Institute of Software Chinese Academy of Sciences Beijing 100080 China Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China Surface Physics Laboratory National Key Laboratory Fudan University Shanghai 200433 Institute of Solid State Physics Chinese Academy of Sciences Hefei 230031 China

The teracluster LSSC-II installed at the State key laboratory of Scientific and engineering Computing, Chinese Academy of Sciences is one of the most powerful PC clusters in China. It has a peek performance of 2Tflops. With a Linpack performance of 1.04Tflops, it is ranked at the 43rd place in the 20th TOP500 List (November 2002), 51st place in the 21st TOP500 List (June 2003), and the 82nd place in the 22nd TOP500 List (November 2003) with a new Linpack performance of 1.3Tflops. In this paper, we present some design principles of this cluster, as well as its applications in some large-scale numerical simulations.

关键词： high performance computing PC cluster large scale numerical simulations

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Routing strategy for satellite-based networks with a hierarchical space grid architecture 4

Routing strategy for satellite-based networks with a hierarc...

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Joint Conference of the 4th International Conference on Information, Communications and Signal Processing and 4th Pacific-Rim Conference on Multimedia, ICICS-PCM 2003

作者： Zhao, Z.W. Zhang, Jun Sun, Fuchun Li, Lei Chen, I-Ming Singapore-MIT Alliance Program Singapore School of Electronic and Information Engineering Beijing University of Aeronautics and Astronautics Beijing China National Key Laboratory of Intelligence and System Tsinghua University Beijing China Institute of Software Chinese Academy of Sciences Beijing China

ISBN: (纸本)0780381858

Routing algorithms and the hierarchical three-dimensional grid architecture of satellite-based networks (SN) are presented. The performance of the proposed architecture and the routing algorithms are analyzed. Simulation of the routing algorithm based on the extended OPNET platform is performed. It is shown in simulation that the proposed three-dimensional satellite-based network architecture outperforms other SN architectures, and the corresponding routing algorithms have superior performances in simplicity, expandability, robustness and high-speed convergence. The full protocols and the related algorithms of routing and switching for the satellite-based networks then can be proposed and verified on an OPNET platform. © 2003 IEEE.

关键词： Routing algorithms

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A new measure for evaluating level of service for traffic operational systems

A new measure for evaluating level of service for traffic op...

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2003 IEEE International Conference on Intelligent Transportation systems, ITSC 2003

作者： Tang, Shuming Wang, Fei-Yue Key Laboratory Complex Systems and Intelligence Science Institute of Automation Chinese Academy of Sciences Room 925 Automation Building Zhongguanchun East Road No. 95 Beijing100080 China Department of System and Industrial Engineering University of Arizona TucsonAZ85721 United States

ISBN: (纸本)0780381254

This paper proposes a new measure to evaluate level of service for traffic operation based on the process capability indices (PCIs). A brief introduction to the concepts of PCIs and the characteristics of traffic flow is presented and followed by a discussion on the appropriateness of applying PCIs to measure the quality of traffic flow. Several case studies have conducted to investigate the effectiveness of the proposed new measure for traffic LOS and the results indicate that the speed and density are the most appropriate parameters for this purpose. The paper concludes with directions for future works. © 2003 IEEE.

关键词： Process control

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A new measure for evaluating level of service for traffic operational systems

A new measure for evaluating level of service for traffic op...

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International Conference on Intelligent Transportation

作者： Shuming Tang Fei-Yue Wang Key Laboratory Complex System and Intelligence Science Institute of Automation Chinese Academy and Sciences Beijing China Department of System and Industrial Engineering University of Arizona Tucson Tucson AZ USA Key Laboratory Complex Systems and Intelligence Science Istitute of Automation Chinese Academy and Sciences China

ISBN: (纸本)0780381254

关键词： Communication system traffic control Delay effects Intelligent systems Automation Road vehicles Intelligent transportation systems Fluid flow measurement Density measurement Velocity measurement Road transportation

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An integrated design framework for driver/passenger-oriented trajectory planning

An integrated design framework for driver/passenger-oriented...

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International Conference on Intelligent Transportation

作者： L. Li F.-Y. Wang Department of Systems and Industrial Engineering University of Arizona Tucson Tucson AZ USA Key Laboratory for Complex Systems and Intelligence Science Institute of Automation Chinese Academy of Sciences Beijing China Department of System and Industrial Engineering University of Arizona Tucson Tucson AZ USA

This paper presents an integrated trajectory planning framework for the front wheel steering vehicles that are equipped with digital map systems. It first addresses the importance of the driver and the passengers' requirement for automatic driving. After introducing the concept of optimal driver/passenger-oriented driving performance, several driving performance indices are introduced as following in order to provide a measurement of the automatic driving process. Based on these indices, the whole optimal trajectory planning problem is divided into two incorporated sub problems: the longitudinal trajectory planning problem and the lateral steering trajectory generation problem. Since the driving performance indices are primarily determined by the longitudinal driving procedure of the vehicle, the desired optimal longitudinal trajectory is formulated first. With the obtained velocity setting of the longitudinal trajectory planning problem, the lateral steering trajectory generation problem is solved based on cell mapping method then.

关键词： Trajectory Vehicle driving Road vehicles Road transportation Path planning Wheels Intelligent vehicles Tracking Automotive engineering systems engineering and theory

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