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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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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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Virtual Array Processing for Active Radar and Sonar Sensing

Virtual Array Processing for Active Radar and Sonar Sensing

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Asilomar Conference on Signals, Systems & computers

作者： Louis L. Scharf Ali Pezeshki Departments of Electrical and Computer Engineering and Statistics Colorado State University Fort Collins CO USA Program Applied and Computational Mathematics Princeton University Princeton NJ USA

In this paper, we describe how an active radar/sonar imaging problem may be formulated as a virtual passive sensor array processing problem. We consider an active sensing problem where it is desired to form a range-Doppler image at a slow- time rate, even though the radar/sonar can transmit pulses at a fast time rate. By transmitting pulses at the fast time rate we can estimate the second-order statistics of an ambiguity vector, calculated at a coarse resolution. As we show this ambiguity vector plays the role of an array snapshot vector in passive sensor array processing. The noise free version of this ambiguity vector acts as a signature vector or steering vector, which can be steered around in delay and Doppler at a fine resolution to produce an image. We employ a MVDR-like principle to generate high resolution delay-Doppler images.

关键词： Array signal processing Sonar Sensor arrays Radar imaging Delay Image resolution Passive radar Image sensors Sensor phenomena and characterization Statistics

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An information theoretic framework for eukaryotic gradient sensing 06

An information theoretic framework for eukaryotic gradient s...

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Proceedings of the 20th International Conference on Neural Information Processing Systems

作者： Joseph M. Kimmel Richard M. Salter Peter J. Thomas Computer Science Program Oberlin College Oberlin Ohio and Computational Neuroscience Graduate Program The University of Chicago Computer Science Program Oberlin College Oberlin Ohio and Oberlin Center for Computation and Modeling Departments of Mathematics Biology and Cognitive Science Case Western Reserve University Cleveland Ohio and Oberlin College Research Associate

Chemical reaction networks by which individual cells gather and process information about their chemical environments have been dubbed "signal transduction" networks. Despite this suggestive terminology, there have been few attempts to analyze chemical signaling systems with the quantitative tools of information theory. Gradient sensing in the social amoeba Dictyostelium discoideum is a well characterized signal transduction system in which a cell estimates the direction of a source of diffusing chemoattractant molecules based on the spatiotemporal sequence of ligand-receptor binding events at the cell membrane. Using Monte Carlo techniques (MCell) we construct a simulation in which a collection of individual ligand particles undergoing Brownian diffusion in a three-dimensional volume interact with receptors on the surface of a static amoeboid cell. Adapting a method for estimation of spike train entropies described by Victor (originally due to Kozachenko and Leonenko), we estimate lower bounds on the mutual information between the transmitted signal (direction of ligand source) and the received signal (spatiotemporal pattern of receptor binding/unbinding events). Hence we provide a quantitative framework for addressing the question: how much could the cell know, and when could it know it? We show that the time course of the mutual information between the cell's surface receptors and the (unknown) gradient direction is consistent with experimentally measured cellular response times. We find that the acquisition of directional information depends strongly on the time constant at which the intracellular response is filtered.

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Quadruped robot obstacle negotiation via reinforcement learning

Quadruped robot obstacle negotiation via reinforcement learn...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Honglak Lee Yirong Shen Chih-Han Yu G. Singh A.Y. Ng Stanford University Stanford CA US Department of Electrical Engineering University of Stanford Stanford CA USA Scientific Computing and Computational Mathematics Program University of Stanford Stanford CA USA Computer Science Department University of Stanford Stanford CA USA

Legged robots can, in principle, traverse a large variety of obstacles and terrains. In this paper, we describe a successful application of reinforcement learning to the problem of negotiating obstacles with a quadruped robot. Our algorithm is based on a two-level hierarchical decomposition of the task, in which the high-level controller selects the sequence of foot-placement positions, and the low-level controller generates the continuous motions to move each foot to the specified positions. The high-level controller uses an estimate of the value function to guide its search; this estimate is learned partially from supervised data. The low-level controller is obtained via policy search. We demonstrate that our robot can successfully climb over a variety of obstacles which were not seen at training time

关键词： Learning Robot kinematics Legged locomotion Foot Mobile robots Leg Motion control Robotics and automation Path planning computer science

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Value function approximation with diffusion wavelets and Laplacian eigenfunctions

Value function approximation with diffusion wavelets and Lap...

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2005 Annual Conference on Neural Information Processing Systems, NIPS 2005

作者： Mahadevan, Sridhar Maggioni, Mauro Department of Computer Science University of Massachusetts Amherst MA 01003 United States Program in Applied Mathematics Department of Mathematics Yale University New Haven CT 06511 United States

ISBN: (纸本)9780262232531

We investigate the problem of automatically constructing efficient representations or basis functions for approximating value functions based on analyzing the structure and topology of the state space. In particular, two novel approaches to value function approximation are explored based on automatically constructing basis functions on state spaces that can be represented as graphs or manifolds: one approach uses the eigenfunctions of the Laplacian, in effect performing a global Fourier analysis on the graph;the second approach is based on diffusion wavelets, which generalize classical wavelets to graphs using multiscale dilations induced by powers of a diffusion operator or random walk on the graph. Together, these approaches form the foundation of a new generation of methods for solving large Markov decision processes, in which the underlying representation and policies are simultaneously learned.

关键词： Diffusion

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Alternating direction finite element method for a class of moving boundary problems

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1st International Symposium on computational and Information science, CIS 2004

作者： Liu, Xu-Zheng Cui, Xia Yong, Jun-Hai Sun, Jia-Guang Department of Computer Science and Technology Tsinghua University Beijing100084 China Laboratory of Computational Physics Institute of Applied Physics Computational Mathematics Beijing100088 China School of Software Tsinghua University Beijing100084 China

ISBN: (纸本)9783540241270

An alternating direction finite element scheme for a class of moving boundary problems is studied. Using coordinate transformations of the spatial variants, a new domain independent of the time is obtained and an ADFE scheme on the new domain is proposed. Then the unique solvability of the approximation scheme is proved, and optimal H1 and L2 norm space estimates and O((∆t)2) estimate for the temporal variant are obtained. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Finite element method

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Numerical solution of saddle point problems

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Acta Numerica 2005年 14卷 1-137页

作者： Benzi, Michele Golubt, Gene H. Liesen, Jörg Department of Mathematics and Computer Science Emory University Atlanta GA 30322 United States Scientific Computing and Computational Mathematics Program Stanford University Stanford CA 94305-9025 United States Institut für Mathematik Technische Universität Berlin D-10623 Berlin Germany

Large linear systems of saddle point type arise in a wide variety of applications throughout computational science and engineering. Due to their indefiniteness and often poor spectral properties, such linear systems represent a significant challenge for solver developers. In recent years there has been a surge of interest in saddle point problems, and numerous solution techniques have been proposed for this type of system. The aim of this paper is to present and discuss a large selection of solution methods for linear systems in saddle point form, with an emphasis on iterative methods for large and sparse problems. © Cambridge University Press, 2005.

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Value function approximation with diffusion wavelets and Laplacian eigenfunctions 05

Value function approximation with diffusion wavelets and Lap...

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Proceedings of the 19th International Conference on Neural Information Processing Systems

作者： Sridhar Mahadevan Mauro Maggioni Department of Computer Science University of Massachusetts Amherst MA Program in Applied Mathematics Department of Mathematics Yale University New Haven CT

We investigate the problem of automatically constructing efficient representations or basis functions for approximating value functions based on analyzing the structure and topology of the state space. In particular, two novel approaches to value function approximation are explored based on automatically constructing basis functions on state spaces that can be represented as graphs or manifolds: one approach uses the eigenfunctions of the Laplacian, in effect performing a global Fourier analysis on the graph; the second approach is based on diffusion wavelets, which generalize classical wavelets to graphs using multiscale dilations induced by powers of a diffusion operator or random walk on the graph. Together, these approaches form the foundation of a new generation of methods for solving large Markov decision processes, in which the underlying representation and policies are simultaneously learned.

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GISolve: A grid-based problem solving environment for computationally intensive geographic information analysis

GISolve: A grid-based problem solving environment for comput...

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3rd International Workshop on Challenges of Large Applications in Distributed Environments, CLADE 2005

作者： Wang, Shaowen Armstrong, Marc P. Ni, Jun Liu, Yan Academic Technologies - Research Services of Information Technology Services University of Iowa Iowa City IA 52242 Department of Geography University of Iowa Iowa City IA 52242 Program in Applied Mathematical and Computational Science University of Iowa Iowa City IA 52242 Department of Computer Science University of Iowa Iowa City IA 52242

ISBN: (纸本)0780390431

The purpose of this paper is to demonstrate the design and implementation of GISolve - a Grid-based problem solving environment for computationally intensive geographic information analysis based on geo-middleware. The geo-middleware resides between existing Grid middleware and geographic information analysis applications to manage heterogeneous and dynamic resources on behalf of analysis applications. At the same time, GISolve provides adaptive domain decomposition solutions to parallel geographic information analysis applications. Based on these domain decomposition solutions, GISolve also schedules distributed tasks and manages data transfers. In GISolve, these capabilities are designed as Grid services that are compliant with the open Grid service architecture (OGSA) and are implemented using Grid portal technologies. The GISolve implementation is illustrated based on a case study of a computationally intensive spatial statistic - [Gi(d)] that is used to assess spatial dependence among geographically distributional observations. © 2005 IEEE.

关键词： Problem solving

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