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Pedestrian flow in a lattice gas model with parallel update

Physical Review E 2010年第2期82卷 026113-026113页

作者： Qing-Yi Hao Mao-Bin Hu Xue-Qi Cheng Wei-Guo Song Rui Jiang Qing-Song Wu School of Engineering Science University of Science and Technology of China Hefei 230026 China School of Mathematics and Computational Science Anqing Teachers College Anqing 246133 China Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China State Key Laboratory of Fire Science University of Science and Technology of China Hefei 230026 China

This paper studies unidirectional pedestrian flow in a channel using the lattice gas model with parallel update rule. The conflict (i.e., several pedestrians intend to move to the same site) is solved by introducing probabilities as in floor field models. The fundamental diagram (FD) is investigated and it is found that when the drift strength D≲0.5, the FD is a concave curve. With the further increase in drift strength, a turning point appears on FD. The empirical findings show that both concave FD and FD with a turning point exist. Thus, the model might be able to reproduce both by tuning drift strength. It is also shown that in the special case D=1, two congested branches exist in the FD. We have carried out mean-field analysis of the FD and the mean-field results are in approximate agreement with simulations when the drift strength D is small. A comparison with random sequential update rule model is also made.

关键词： Gas dynamics

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Fast Facial Fitting Based on Mixture Appearance Model with 3D Constraint

Fast Facial Fitting Based on Mixture Appearance Model with 3...

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Chinese Conference on Pattern Recognition (CCPR)

作者： Xiangsheng Huang Lujin Gong Xiaoyan Wang Institute of Automation Chinese Academy and Sciences Beijing China State Key Laboratory of Scientific and Engineering Computing AMSS Institute of Computational Mathematics and Scientific/Engineering Computing Chinese Academy and Sciences Beijing China College of Computer Science and Technology Zhejiang University of Technology Hangzhou China

Fast facial points fitting plays an important role in applications such as Human-Computer Interaction, entertainment, surveillance, and is highly relevant to the techniques of facial expression analysis, face recognition, 3D face model generation, etc. Active Appearance Models (AAMs) are generative models commonly used to fit face. They are sensitive to illumination and expression changes because they use only raw intensity to build observation models. In this paper, a real time facial points fitting approach using mixture observation models is presented. Furthermore, the 3D modes are used to constrain the AAM so that it can only generate model instances that can also be generated with the 3D modes. Finally, we give a derivative process for fast energy minimization using the inverse compositional algorithm. A coarse-to-fine fitting strategy is used for realtime and robust facial points fitting. We apply this algorithm to facial expression cloning of 3D Avatar system. Experimental results demonstrate that fitting the AAM with mixture observation models and 3D constraint outperforms other classical algorithms.

关键词： Three dimensional displays Shape Active appearance model Solid modeling Face Pixel Robustness

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EMI and EMC analysis of arbitrarily shaped power-ground planes

EMI and EMC analysis of arbitrarily shaped power-ground plan...

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Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC)

作者： Guo-Ping Zou Er-Ping Li Xing-Chang Wei Guang-Xiao Luo Xiang-Cui School of Electrical and Electronic Engineering North China Electric Power University Beijing China Computational Electronics and Photonics Institute of High Performance Computing Agency for Science Technology and Research Singapore

ISBN: (纸本)9781424456215;9781424456239

The radiation from a power-ground planes structure in high-speed printed circuit boards due to high switching noise current is investigated in this paper. A 2D contour integral method is used to characterize the radiation from the power-ground planes. The contour integral method can model an arbitrarily shaped power-ground planes pair more efficient than 3D numerical methods. By combining the noise current source with the [Z] matrix of power-ground planes, the edge voltage and electric field are obtained. Based on the field equivalent principle, the equivalent magnetic current around the edges of power-ground planes is obtained. Thereafter, the radiated intensity is calculated by equivalent magnetic current and free-space Green function.

关键词： Electromagnetic interference Electromagnetic compatibility Circuit noise Noise shaping Printed circuits Switching circuits Magnetic noise Transmission line matrix methods Voltage Green function

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Lecture Notes in Computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics): Preface

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Lecture Notes in Computer science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2010年 6130 LNCS卷 VI页

作者： Mourrain, Bernard Schaefer, Scott Xu, Guoliang GALAAD Inria Méditerranée 2004 route des Lucioles 06902 Sophia Antipolis Cedex France Texas A and M University Department of Computer Science College Station TX 77843-3112 United States Chinese Academy of Science Institute of Computational Mathematics and Scientific/Engineering Computing Beijing 100080 China

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Notice of Retraction: Application of improved genetic algorithm in microstructure optimization of closed-cell material

Notice of Retraction: Application of improved genetic algori...

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International Conference on Computer Application and System Modeling (ICCASM)

作者： Junfeng Zhao Junzhi Cui Wei Li Department of Applied Mathematics Northwestern Polytechnical University Xi'an Shaanxi P.R.China Institute of Computational Mathematics and Science-Engineering Computing Chinese Academy of Sciences Beijing P.R.China Department of Mathematics Xidian University Xi'an Shaanxi P.R.China

This article has been retracted by the publisher.

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Cardiac valve annulus manual segmentation using computer assisted visual feedback in three-dimensional image data

Cardiac valve annulus manual segmentation using computer ass...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Ramón Casero Rebecca A.B. Burton T. Alexander Quinn Christian Bollensdorff Patrick Hales Jürgen E. Schneider Peter Kohl Vicente Grau Computational Biology Group Computing Laboratory University of Oxford Oxford UK Cardiac Mechano Electric Feedback lab Department of Physiology Anatomy and Genetics University of Oxford Oxford UK Department of Cardiovascular Medicine Wellcome Trust Centre of Human Genetics University of Oxford Oxford UK Institute of Biomedical Engineering Department of Engineering Science University of Oxford Oxford UK

Annulus manual segmentation is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral, tricuspid, aortic and pulmonary). In this paper we review two traditional manual segmentation approaches: slice-by-slice and interpolating a sparse set of landmarks with a spline curve. We propose a new Spline Tool for the open source software platform Seg3D, that is fast and improves spatial coherence by providing visual feedback of the segmentation in real time. The Spline Tool was tested successfully on 14 rat hearts, on all four valves.

关键词： Image segmentation Visualization Valves Biometrics Three dimensional displays Image resolution Biomedical imaging

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Dislocation climb strengthening in systems with immobile obstacles: Three-dimensional level-set simulation study

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Physical Review B 2010年第5期81卷 054104-054104页

作者： Zi Chen Kevin T. Chu David J. Srolovitz Jeffrey M. Rickman Mikko P. Haataja Department of Mechanical and Aerospace Engineering Princeton University Princeton New Jersey 08540 USA Princeton Institute for the Science and Technology of Materials (PRISM) Princeton University Princeton New Jersey 08540 USA Vitamin D Inc. Menlo Park California 94025 USA Institute of High Performance Computing Singapore Singapore Department of Materials Science and Engineering Lehigh University Bethlehem Pennsylvania 18015 USA Department of Physics Lehigh University Bethlehem Pennsylvania 18015 USA Program in Applied and Computational Mathematics (PACM) Princeton University Princeton New Jersey 08540 USA

We employ a parallel, three-dimensional level-set code to simulate the dynamics of isolated dislocation lines and loops in an obstacle-rich environment. This system serves as a convenient prototype of those in which extended, one-dimensional objects interact with obstacles and the out-of-plane motion of these objects is key to understanding their pinning-depinning behavior. In contrast to earlier models of dislocation motion, we incorporate long-ranged interactions among dislocation segments and obstacles to study the effect of climb on dislocation dynamics in the presence of misfitting penetrable obstacles/solutes, as embodied in an effective climb mobility. Our main observations are as follows. First, increasing climb mobility leads to more effective pinning by the obstacles, implying increased strengthening. Second, decreasing the range of interactions significantly reduces the effect of climb. The dependence of the critical stress on obstacle concentration and misfit strength is also explored and compared with existing models. In particular, our results are shown to be in reasonable agreement with the Friedel-Suzuki theory. Finally, the limitations inherent in the simplified model employed here, including the neglect of some lattice effects and the use of a coarse-grained climb mobility, are discussed.

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A two-order and two-scale computation method for nonselfadjoint elliptic problems with rapidly oscillatory coefficients

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Applied Mathematics and Mechanics(English Edition) 2009年第12期30卷 1579-1588页

作者：苏芳崔俊芝徐湛 Department of Mathematics and Systems Science National University of Defense Technology Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of Sciences School of Electronic Science and Engineering National University of Defense Technology

The purpose of this paper is to solve nonselfadjoint elliptic problems with rapidly oscillatory coefficients. A two-order and two-scale approximate solution expression for nonselfadjoint elliptic problems is considered, and the error estimation of the twoorder and two-scale approximate solution is derived. The numerical result shows that the presented approximation solution is effective.

关键词： nonselfadjoint elliptic problems rapidly oscillatory coefficients two-order and two-scale finite element method

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Reports of the AAAI 2010 conference workshops

Reports of the AAAI 2010 conference workshops

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作者： Aha, David W. Boddy, Mark Bulitko, Vadim D'Avila Garcez, Artur S. Doshi, Prashant Edelkamp, Stefan Geib, Christopher Gmytrasiewicz, Piotr Goldman, Robert P. Halevy, Alon Hitzler, Pascal Isbell, Charles Josyula, Darsana Kaelbling, Leslie Pack Kersting, Kristian Kunda, Maithilee Lamb, Luis C. Marthi, Bhaskara McGreggor, Keith Mihalkova, Lilyana Nastase, Vivi Natarajan, Sriraam Provan, Gregory Raja, Anita Ram, Ashwin Riedl, Mark Russell, Stuart Sabharwal, Ashish Smaus, Jan-Georg Sukthankar, Gita Tuyls, Karl Van Der Meyden, Ron Adaptive Systems Section Naval Research Laboratory Washington DC United States Adventium Labs. Minneapolis MN United States Department of Computer Science University of Alberta Canada City University London United Kingdom University of Georgia United States University of Bremen Germany School of Informatics University of Edinburgh United Kingdom University of Illinois Chicago United States Smart Information Flow Technologies LLC Minneapolis MN United States Structured Data Group Google Research United States Department of Computer Science Wright State University Dayton OH United States School of Interactive Computing Georgia Institute of Technology Atlanta GA United States Department of Computer Science Bowie State University United States Department of Computer Science and Engineering Massachusetts Institute of Technology United States Statistical Relational Mining Group Fraunhofer IAIS Germany Department of Computer Science Federal University of Rio Grande Do sul Brazil Willow Garage Inc. CA United States Computer Science Department University of Maryland College Park United States Heidelberg Institute for Theoretical Studies Heidelberg Germany Department of Computer Science University of Wisconsin Madison United States University College Cork Ireland Cork Complex Systems Lab. Ireland Department of Software and Information Systems University of North Carolina Charlotte United States Department of Computer Science and Engineering University of California Berkeley United States Department of Computer Science Cornell University United States Institute for Computational Sustainability United States University of Freiburg Germany School of Electrical Engineering and Computer Science University of Central Florida United States Maastricht University Netherlands University of New South Wales NICTA Australia

The AAAI-10 workshop program was held on July 11-12, 2010, at the Westin Peachtree Plaza in Atlanta, Georgia. The workshop program included 13 workshops covering a wide range of topics in artificial intelligence. There were several presentations on particular formalisms for combining the levels of planning from the perspectives of classical planning, motion planning, POMDPs, search-based planning, and temporal logic-based constraints. Henry Lieberman from Massachusetts institute of Technology Media Laboratory presented work developing a platform for knowledge acquisition and usage from expert users, built upon experience with eliciting information from nonexperts in a collaborative manner. The objective of the AAAI Workshop on Goal-Directed Autonomy (GDA) was to encourage discussion and novel contributions on intelligent agents that can self-select their goals. Jeremy Baxter from QinetiQ focused on user interaction, while Nick Hawes described a goal-directed reasoning framework for controlling a mobile robot.

关键词： Motion planning

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A Parallel Algorithm for Adaptive Local Refinement of Tetrahedral Meshes Using Bisection

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Numerical Mathematics(Theory,Methods and Applications) 2009年第1期2卷 65-89页

作者： Lin-Bo Zhang State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China.

Local mesh refinement is one of the key steps in the implementations of adaptive finite element methods. This paper presents a parallel algorithm for distributed memory parallel computers for adaptive local refinement of tetrahedral meshes using bisection. This algorithm is used in PHG, Parallel Hierarchical Grid Chttp：//lsec. cc. ac. cn/phg/）, a toolbox under active development for parallel adaptive finite element solutions of partial differential equations. The algorithm proposed is characterized by allowing simukaneous refinement of submeshes to arbitrary levels before synchronization between submeshes and without the need of a central coordinator process for managing new vertices. Using the concept of canonical refinement, a simple proof of the independence of the resulting mesh on the mesh partitioning is given, which is useful in better understanding the behaviour of the biseetioning refinement procedure.

关键词： Adaptive refinement bisection tetrahedral mesh parallel algorithm MPI.

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