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Solitons in two-dimensional lattices possessing defects, dislocations, and quasicrystal structures

Physical Review E 2006年第3期74卷 035601(R)-035601(R)页

作者： Mark J. Ablowitz Boaz Ilan Ethan Schonbrun Rafael Piestun Department of Applied Mathematics University of Colorado Boulder Colorado 80309-0526 USA School of Natural Sciences University of California Merced P.O. Box 2039 Merced California 95344 USA Department of Electrical and Computer Engineering University of Colorado Boulder Colorado 80309-0425 USA

Localized nonlinear modes, or solitons, are obtained for the two-dimensional nonlinear Schrödinger equation with various external potentials that possess large variations from periodicity, i.e., vacancy defects, edge dislocations, and quasicrystal structure. The solitons are obtained by employing a spectral fixed-point computational scheme. Investigation of soliton evolution by direct numerical simulations shows that irregular-lattice solitons can be stable, unstable, or undergo collapse.

关键词： NONLINEAR PHOTONIC LATTICES WAVE ARRAYS TRAINS LIGHT

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P1H-2 Particle Sizing in the Process Industry using Hertz-Zener Impact Theory and Acoustic Emission Spectra

P1H-2 Particle Sizing in the Process Industry using Hertz-Ze...

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IEEE Symposium (IUS) Ultrasonics

作者： A. Gachagan A. J. Mulholland G. Hayward M. Tramontana A. Nordon G. Carson Department of Mathematics University of Strathclyde Glasgow UK Department of Pure and Applied Chemistry Centre for Process Analytics and Control Technology (CPACT) University of Strathclyde Glasgow UK Department of Electronic and Electrical Engineering The Centre for Ultrasonic Engineering (CUE) University of Strathclyde Glasgow UK

The cost of implementing real-time monitoring and control of industrial processes is a significant barrier for many companies. Acoustic techniques provide complementary information to optical spectroscopic sensors and have a number of advantages: they are relatively inexpensive, can be applied non-invasively, are non-destructive, multi-point measurements are possible, opaque samples can be analysed in containers that are made from opaque materials (e.g. steel or concrete) and the analysis can be conducted in real-time. In this paper a new theoretical model is proposed which describes the transport of particles in a stirred reactor, their collision with the reactor walls, the subsequent vibrations which are then transmitted through the vessel walls, and their detection by an ultrasonic transducer. The particle-wall impact is modelled using Hertz-Zener impact theory. Experimental data is then used in conjunction with this (forward) model to form an inverse problem for the particle size distribution using a least squares cost function. Application of an integral smoothing operator to the power spectra greatly enhances the accuracy and robustness of the approach. One advantage of this new approach is that since it operates in the frequency domain, it can cope with the industrially relevant case of many particle-wall collisions. The technique will be illustrated using data from a set of controlled experiments. In the first instance a set of simplified experiments involving single particles being dropped in air onto a substrate are utilised. The second set of experiments involves particles in a carrier fluid being stirred in a reactor vessel. In each case the approach is able to successfully recover the associated particle size

关键词： Acoustic emission Inductors Optical sensors Information analysis Costs Monitoring Process control Industrial control Stimulated emission Spectroscopy

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Nonminimum phase output tracking control strategies for DC-to-DC power converters

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Lecture Notes in Control and Information Sciences 2006年 334卷 447-482页

作者： Zinober, Alan Shtessel, Yuri Fossas, Enric Olm, Josep Patterson, Joe Department of Applied Mathematics University of Sheffield Sheffield S10 2TN United Kingdom Department of Electrical and Computer Engineering University of Alabama in Huntsville Huntsville AL 35899 United States Institute of Industrial and Control Engineering Technical University of Catalonia Barcelona 08028 Spain Department of Applied Mathematics IV Technical University of Catalonia Barcelona 08034 Spain Electronics Simulation Analysis and Modeling US Army AMCOM Redstone Arsenal AL 35898 United States

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High-Order Sliding-Mode Observer for Linear Systems with Unknown Inputs

High-Order Sliding-Mode Observer for Linear Systems with Unk...

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Mediterranean Conference on Control and Automation (MED)

作者： Leonid Fridman Arie Levant Jorge Davila Department of Control Division of Electrical Engineering Facultad de Ingenieria Universidad Nacional Autonoma de Mexico Mexicali Mexico Applied Mathematics Department School of Mathematical Sciences Tel-Aviv University Tel-Aviv Israel

Extended sufficient conditions for the observation of linear time invariant systems with unknown inputs are formulated. A new observation scheme is proposed. An additional linear term ensuring global stability is included for this sake in the differentiation algorithm based on high-order sliding-modes. The global robust finite-time-convergent estimation of observable states and unknown inputs is obtained, exact in the absence of measurement noises. Under the detectability conditions the whole state is asymptotically estimated. The accuracy of the estimation in the presence of bounded deterministic Lebesgue-measurable noises and discrete sampling is worked out

关键词： Linear systems State estimation Observers Time invariant systems Sampling methods Noise robustness Noise measurement Sliding mode control Robust stability Asymptotic stability

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DraXRouter: global routing in X-architecture with dynamic resource assignment 06

DraXRouter: global routing in X-architecture with dynamic re...

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Asia and South Pacific Design Automation Conference

作者： Zhen Cao Tong Jing Yu Hu Yiyu Shi Xianlong Hong Xiaodong Hu Guiying Yan Computer Science & Technology Department Tsinghua University Beijing China Electrical Engineering Department University of California Los Angeles Los Angeles CA USA Institute of Applied Mathematics Chinese Academy and Sciences Beijing China

ISBN: (纸本)9780780394513

In recent years, the X-architecture is introduced to obtain better performance for integrated circuit physical design. This paper reformulates the global routing problem in X-architecture under the liquid routing model. Then, a dynamic resource assignment (Dra) method is presented to reduce potential vias. At last, a global router called DraXRouter, is designed, in which we adopt a dynamic-tabulist-based tree construction algorithm and a stochastic optimization strategy to gain high quality routing solution. Tested on ISPD'98 benchmarks, DraXRouter achieves better routing performance compared with two recent global routers.

关键词： Routing Integrated circuit interconnections Wire Algorithm design and analysis Design optimization Stochastic processes Benchmark testing Delay Space technology Heuristic algorithms

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Notes on averaging over acyclic digraphs and discrete coverage control

Notes on averaging over acyclic digraphs and discrete covera...

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IEEE Conference on Decision and Control

作者： Chunkai Gao Francesco Bullo Jorge Cortes Ali Jadbabaie Center for Control Dynamical Systems and Computation and the Department of Mechanical Engineering University of California Santa Barbara CA USA Department of Applied Mathematics and Statistics University of California Santa Cruz CA USA Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia PA USA

ISBN: (纸本)1424401704;9781424401703

In this paper, we show the relationship between two algorithms and optimization problems that are the subject of recent attention in the networking and control literature. First, we obtain some results on averaging algorithms over acyclic digraphs with fixed and controlled-switching topology. Second, we discuss continuous and discrete coverage control laws. Further, we show how discrete coverage control laws can be cast as averaging algorithms over discrete Voronoi graphs

关键词： Optimal control Distributed control Algorithm design and analysis Convergence USA Councils Network topology Robot sensing systems Robot kinematics Drives Laplace equations

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Quantum Key Distribution Based on Arbitrarily Weak Distillable Entangled States

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Physical Review Letters 2006年第7期96卷 070501-070501页

作者： Karol Horodecki Debbie Leung Hoi-Kwong Lo Jonathan Oppenheim Department of Mathematics Physics and Computer Science University of Gdańsk 80-952 Gdańsk Poland Institute of Quantum Information MSC 107-81 Caltech Pasadena California 91125 USA Department of Electrical and Computer Engineering and Department of Physics University of Toronto Toronto Ontario M5S 3G4 Canada Department of Applied Mathematics and Theoretical Physics University of Cambridge United Kingdom

States with private correlations but little or no distillable entanglement were recently reported. Here, we consider the secure distribution of such states, i.e., the situation when an adversary gives two parties such states and they have to verify privacy. We present a protocol which enables the parties to extract from such untrusted states an arbitrarily long and secure key, even though the amount of distillable entanglement of the untrusted states can be arbitrarily small.

关键词： Quantum theory

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Auger recombination of excitons in one-dimensional systems

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Physical Review B 2006年第24期73卷 245424-245424页

作者： Feng Wang Yang Wu Mark S. Hybertsen Tony F. Heinz Departments of Physics and Electrical Engineering Columbia University New York New York 10027 USA Center for Electron Transport in Molecular Nanostructures Columbia University New York New York 10027 USA Department of Applied Physics and Applied Mathematics Columbia University New York New York 10027 USA

In tightly confined one-dimensional (1D) systems, the effective Coulomb interaction is greatly enhanced and optical transitions generally lead to the formation of strongly bound excitons. When more than one exciton is present, the Coulomb interaction also leads to rapid exciton-exciton annihilation through an Auger recombination process. This effect, which may be significant even at low exciton densities, can be described by a rate law governing two-body interactions. The Auger recombination rate for excitons in a strongly confined 1D system is analyzed. The rate increases sharply with exciton binding energy, but varies only weakly with temperature. An explicit expression for the Auger recombination rate in terms of the exciton binding energy, optical matrix element and reduced carrier mass is derived for a two-band model in which the Coulomb interaction is approximated by a point-contact potential. Results for the prototypical 1D system of single-walled carbon nanotubes are obtained and compared with experiment.

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Parameter Stability of the Structural-Functional Model GREENLAB-Tomato as Affected by Plant Density and Biomass Data Acquisition

Parameter Stability of the Structural-Functional Model GREEN...

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International Symposium on Plant Growth Modeling and Applications (PMA)

作者： G. Louarn Q.X. Dong Y.M. Wang J.F. Barczi P. de Reffye Sino-French Laboratory of Informatics Automation and Applied Mathematics (LIAMA) Chinese Academy and Sciences Beijing China Department of Electronic Information College of Information and Electrical Engineering China Agricultural University Beijing China CIRAD UMR AMAP Montpellier France Digiplant Program INRIA Rocquencourt Le Chesnay France

In this study, we assessed the possibility of using the GREENLAB model to quantitatively simulate adaptive responses of tomato plants competing for light. The model was able to reproduce modifications induced by a reduction of plant spacing in dry matter production and in the allocation pattern. However, the analysis of parameter stability showed that some parameters were environment dependent and that an adjustment of model formalisms was required to explicitly represent the plant response. Model parameters also proved to be sensitive to the data acquisition procedure. We confirmed that target files composed of dry matter records lead to parameters that were better indicators of the carbohydrates metabolism at all densities.

关键词： Stability Bioinformatics Biomass Crops Predictive models Irrigation Production Data visualization Educational institutions Laboratories

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Comparison of linear and non-linear PLS methods for soft-sensing of an SBR for nutrient removal

Comparison of linear and non-linear PLS methods for soft-sen...

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3rd Biennial Meeting of the International Environmental Modelling and Software Society: Summit on Environmental Modelling and Software, iEMSs 2006

作者： Villez, K. Lee, D.S. Rosen, C. Vanrolleghem, P.A. BIOMATH Department of Applied Mathematics Biometrics and Process Control Ghent Univeristy Coupure Links 653 B-9000 Gent Belgium Department of Environmental Engineering Kyungpook National University Sankyuk-dong Buk-gu Daegu 702-701 Korea Republic of IEA: Department of Industrial Electrical Engineering and Automation Lund University LTH SE-221 00 Lund Sweden ModelEAU: Département de Génie Civil Pavillon Pouliot Université Laval Québec QC G1K 7P4 Canada

ISBN: (纸本)1424308526

Despite of promising results in research, advanced control strategies fail to gain trust in wastewater treatment practice. Due to the sensitivity of the biological processes to disturbances, operators are often unable to find the causes of faults due to the lack of effective real-time on-line monitoring. Strategies for on-line monitoring are therefore essential to enhance biological process control. Therefore, a suitable multivariate soft-sensor is desired for fault detection and control for a pilot-scale sequencing batch reactor (SBR) system to allow effluent quality to be estimated well before off-line analysis is finished. For this purpose, several multivariate methods are available, including (linear) partial least squares (PLS), Neural Net PLS (NNPLS) and Kernel PLS (KPLS). While non-linear extensions of PLS such as NNPLS require fitting of non-linear functions, KPLS does not. KPLS is based on a non-linear transformation of the process data, followed by the fitting of a linear PLS model between the transformed inputs and outputs. PLS, NNPLS and KPLS were compared regarding their ability to predict effluent quality data and their computational requirements. While (linear) PLS and NNPLS lead to acceptable prediction, KPLS results in poor model performance. Moreover, the computational requirement of KPLS were large compared to PLS and NNPLS. When comparing PLS and NNPLS to each other, it was found that NNPLS leads to the best possible prediction given the experimental data set, while the extra computational requirements are minimal.

关键词： Neural networks

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