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Guest editorial nonlinear optimization of communication systems

IEEE Journal on Selected Areas in Communications 2006年第8期24卷 1421-1423页

作者： Chiang, Mung Low, Steven H. Luo, Zhi-Quan Shroff, Ness B. Yu, Wei Steenstrup, M. Princeton University Department of Electrical Engineering Program in Applied and Computational Mathematics Princeton NJ 08544 United States California Institute of Technology Department of Computer Science Pasadena CA 91125 United States University of Minnesota Department of Electrical and Computer Engineering Minneapolis MN 55455 United States Purdue University School of Electrical and Computer Engineering West Lafayette IN 47907 United States University of Toronto Edward S. Rogers Sr. Department of Electrical and Computer Engineering Toronto Ont. M4S 3G5 Canada

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关键词： Communication systems Design optimization Communication system control Optimization methods Protocols Distributed algorithms Power system modeling Nonlinear control systems Lagrangian functions Surges

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A first-principle study of one-dimensional carbon atomic chain inserted single-wall carbon nanotubes

A first-principle study of one-dimensional carbon atomic cha...

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作者： Mao, Yuliang Zhong, JianXin Yuan, JianMei Zhao, Xinluo Ando, Yoshinori Key Laboratory for Advanced Materials and Rheological Properties Xiangtan University Ministry of Education Xiangtan 411105 Hunan China Computer Science and Mathematics Division Oak Ridge National Laboratory P. O. Box 2008 Oak Ridge TN 37831-6016 United States Institute for Computational and Applied Mathematics Xiangtan University Xiangtan 411105 Hunan China Department of Materials Science and Engineering Meijo University Nagoya 468-8502 Japan

Using first principles calculations, we investigate the atomic and electronic structure of carbon nanowires (CNWs) as the carbon chain inserted into single wall carbon nanotubes (SWCNTs). It indicates that the (5,5) CNW system exhibits metallic character, however, the insertion of carbon chain can transit a semi-conducting (9,0) SWCNT into a metallic. Copyright © 2006 American Scientific Publishers All rights reserved.

关键词： Carbon nanotubes

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Instantaneous Radar Polarimetry with Multiple Dually-polarized Antennas

Instantaneous Radar Polarimetry with Multiple Dually-polariz...

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Asilomar Conference on Signals, Systems & computers

作者： A. R. Calderbank S. D. Howard W. Moran A. Pezeshki M. Zoltowski Program Applied and Computational Mathematics Princeton University Princeton NJ USA Defence Science and Technology Organization Edinburgh Australia Electrical Engineering and Computer Science University of Melbourne Melbourne Australia Electrical and Computer Engineering Purdue University West Lafayette IN USA

Fully polarimetric radar systems are capable of simultaneously transmitting and receiving in two orthogonal polarizations. Instantaneous radar polarimetry exploits both polarization modes of a dually-polarized radar transmitter and receiver on a pulse by pulse basis, and can improve the radar detection performance and suppress range sidelobes . In this paper, we extend the use of instantaneous radar polarimetry for radar systems with multiple dually-polarized transmit and receive antennas. Alamouti signal processing is used to coordinate transmission of Golay pairs of phase codes waveforms across polarizations and multiple antennas. The integration of multi- antenna signal processing with instantaneous radar polarimetry can further improve the detection performance, at a computational cost comparable to single channel matched filtering.

关键词： Radar polarimetry Radar antennas Polarization Radar detection Radar signal processing Transmitters Receiving antennas Transmitting antennas computational efficiency Matched filters

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Landau-Zener tunneling in a nonlinear three-level system

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Physical Review A 2006年第3期74卷 033414-033414页

作者： Guan-Fang Wang Di-Fa Ye Li-Bin Fu Xu-Zong Chen Jie Liu Institute of Applied Physics and Computational Mathematics P.O. Box 8009 (28) 100088 Beijing China Institute of Physical Science and Technology Lanzhou University 730000 Lanzhou China Key Laboratory for Quantum Information and Measurements Ministry of Education School of Electronics Engineering and Computer Science Peking University Beijing 100871 China

We present a comprehensive analysis of the Landau-Zener tunneling of a nonlinear three-level system in a linearly sweeping external field. We find the presence of nonzero tunneling probability in the adiabatic limit (i.e., very slowly sweeping field) even for the situation that the nonlinear term is very small and the energy levels keep the same topological structure as that of the linear case. In particular, the tunneling is irregular with showing an unresolved sensitivity on the sweeping rate. For the case of fast-sweeping fields, we derive an analytic expression for the tunneling probability with stationary phase approximation and show that the nonlinearity can dramatically influence the tunneling probability when the nonlinear “internal field” resonate with the external field. We also discuss the asymmetry of the tunneling probability induced by the nonlinearity. Physics behind the above phenomena is revealed and possible application of our model to triple-well trapped Bose-Einstein condensate is discussed.

关键词： INTERFERENCE TRANSITION MODEL

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NEKTAR, SPICE and Vortonics: using federated grids for large scale scientific applications

NEKTAR, SPICE and Vortonics: using federated grids for large...

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International Workshop on Challenges of Large Applications in Distributed Environments

作者： B. Boghosian P. Coveney S. Dong L. Finn S. Jha G. Karniadakis N. Karonis Department of Mathematics Tufts University Medford MA USA Centre for Computational Science University College London London UK Division of Applied Mathematics Brown University Providence RI USA Department of Computer Science Northern Illinois University Dekalb IL USA Argonne National Laboratory Argonne IL USA

In response to a joint call from US's NSF and UK's EPSRC for applications that aim to utilize the combined computational resources of the US and UK, three computational science groups from UCL, Tufts and Brown Universities teamed up with a middleware team from NIU/Argonne to meet the challenge. Although the groups had three distinct codes and aims, the projects had the underlying common feature that they were comprised of large-scale distributed applications which required high-end networking and advanced middleware in order to be effectively deployed. For example, cross-site runs were found to be a very effective strategy to overcome the limitations of a single resource. The seamless federation of a grid-of-grids remains difficult. Even if interoperability at the middleware and software stack levels were to exist, it would not guarantee that the federated grids can be utilized for large scale distributed applications. There are important additional requirements for example, compatible and consistent usage policy, automated advanced reservations and most important of all co-scheduling. This paper outlines the scientific motivation and describes why distributed resources are critical for all three projects. It documents the challenges encountered in using a grid-of-grids and some of the solutions devised in response

关键词： SPICE Large-scale systems Educational institutions Middleware Distributed computing High performance computing Proposals Grid computing Application software mathematics

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Collective excitations of a Bose-Einstein condensate in an anharmonic trap

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Physical Review A 2006年第5期74卷 055601-055601页

作者： Guan-Qiang Li Li-Bin Fu Ju-Kui Xue Xu-Zong Chen Jie Liu Institute of Applied Physics and Computational Mathematics P. O. Box 8009 (28) 100088 Beijing People’s Republic of China Physics and Electronics Engineering College Northwest Normal University 730070 Lanzhou People’s Republic of China Key Laboratory for Quantum Information and Measurements Ministry of Education School of Electronics Engineering and Computer Science Peking University Beijing 100871 People’s Republic of China

We investigate the collective excitations of a one-dimensional Bose-Einstein condensate with repulsive interaction between atoms in a quadratic plus quartic trap. Using variational approaches, the coupled equations of motions for the center-of-mass coordinate of the condensate and its width are derived. Then, two low-energy excitation modes are obtained analytically. The frequency shift induced by the anharmonic distortion, and the collapse and revival of the collective excitations originating from the nonlinear coupling between the two modes, are discussed.

关键词： NONLINEAR DYNAMICS GAS

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Parallel PDE-based simulations using the common component architecture

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Lecture Notes in computational science and Engineering 2006年 51卷 327-381页

作者： McInnes, Lois Curfman Allan, Benjamin A. Armstrong, Robert Benson, Steven J. Bernholdt, David E. Dahlgren, Tamara L. Diachin, Lori Freitag Krishnan, Manojkumar Kohl, James A. Walter Larson, J. Lefantzi, Sophia Nieplocha, Jarek Norris, Boyana Parker, Steven G. Ray, Jaideep Zhou, Shujia Mathematics and Computer Science Division Argonne National Laboratory Argonne IL United States Livermore CA United States Computer Science and Mathematics Division Oak Ridge National Laboratory Oak Ridge TN United States Center for Applied Scientific Computing Lawrence Livermore National Laboratory Livermore CA United States Computational Sciences and Mathematics Pacific Northwest National Laboratory Richland WA United States Reacting Flow Research SNL Livermore CA United States Scientific Computing and Imaging Institute University of Utah Salt Lake City UT United States Advanced Software R and D SNL Livermore CA United States Northrop Grumman Corporation Information Technology Sector Chantilly VA United States

ISBN: (纸本)9783540290766

The complexity of parallel PDE-based simulations continues to increase as multimodel, multiphysics, and multi-institutional projects become widespread. A goal of component - based software engineering in such large-scale simulations is to help manage this complexity by enabling better interoperability among various codes that have been independently developed by different groups. The Common Component Architecture (CCA) Forum is defining a component architecture specification to address the challenges of high-performance scientific computing. In addition, several execution frameworks, supporting infrastructure, and general-purpose components are being developed. Furthermore, this group is collaborating with others in the high-performance computing community to design suites of domain-specific component interface specifications and underlying implementations. © Springer-Verlag Berlin Heidelberg 2006.

关键词： Multiphysics

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Partition of unity method on nonmatching grids for the Stokes problem

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Journal of Numerical mathematics 2005年第3期13卷 157-169页

作者： Bacuta, C. Chen, J. Huang, Y. Xu, J. Zikatanov, L. Mathematical Sciences University of Delaware Newark DE 19716 School of Mathematics and Computer Science Nanjing Normal University Nanjing 210097 China Institute for Computational and Applied Mathematics Department of Mathematics Xiangtan University 411105 China Department of Mathematics Pennsylvania State University University Park PA 16802

We consider the Stokes problem on a plane polygonal domain Ω ⊂ 2. We propose a finite element method for overlapping or nonmatching grids for the Stokes problem based on the partition of unity method. We prove that the discrete inf-sup condition holds with a constant independent of the overlapping size of the subdomains. The results are valid for multiple subdomains and any spatial dimension. © VSP 2005.

关键词： Problem solving

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An efficient dynamic load-balancing algorithm in a large-scale cluster

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6th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP

作者： Zhang, Baa-Yin Mo, Ze-Yao Yang, Guang-Wen Zheng, Wei-Min Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Computer Science and Technology Tsinghua University Beijing 100084 China

ISBN: (纸本)3540292357

Random stealing is a well-known dynamic load-balancing algorithm. However, for a large-stale cluster, the simple random stealing policy is no longer efficient because an idle node must randomly steal many times to obtain a task from another node. This will not only increase the idle time for all nodes but also produce a heavy network communication overhead. In this paper, we propose a novel dynamic loadbalancing algorithm, Transitive Random Stealing (TRS), which can make any idle node obtain a task from another node with much fewer stealing times in a large-scale cluster. A probabilistic model is constructed to analyze the performance of TRS, random stealing and Shis, one of load balance policies in the EARTH system. Finally, by the random baseline technique, an experiment designed to compare TRS with Shis and random stealing for five different load distributions in the Tsinghua EastSun cluster convinces us that TRS is a highly efficient dynamic load-balancing algorithm in a large-scale cluster. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Large scale systems

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Scheduling efficiently for irregular load distributions in a large-scale cluster

Scheduling efficiently for irregular load distributions in a...

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3rd International Symposium on Parallel and Distributed Processing and Applications, ISPA 2005

作者： Zhang, Bao-Yin Mo, Ze-Yao Yang, Guang-Wen Zheng, Wei-Min Institute of Applied Physics and Computational Mathematics Beijing 100088 China Department of Computer Science and Technology Tsinghua University Beijing 100084 China

ISBN: (纸本)3540297693

Random stealing is a well-known dynamic scheduling algorithm. However, in a large-scale cluster, an idle node must randomly steal many times to obtain a task from another node, especially, this problem severely affects performance in systems where only a few nodes generate most of the system workload. In this paper, we present an efficient dynamic scheduling algorithm, Transitive Random Stealing (TRS) based on random stealing, which makes any idle node rapidly obtain a task from another node for irregular load distributions in a large-scale cluster. Then by the random baseline technique, we experimentally compare TRS with Shis, one of load balance policies in the EARTH system, and random stealing for different load distributions in the Tsinghua EastSun cluster and show that TRS is a highly efficient scheduling algorithm for irregular load distributions in a large-scale cluster. Finally, TRS is implemented in the Jcluster environment, a high performance Java parallel environment, and an experiment result is given in the HKU Gideon 300 cluster. © Springer-Verlag Berlin Heidelberg 2005.

关键词： Algorithms

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