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IEEE conference on Control applications (CCA)

作者： Cvetanovic, Cecilia Laroche, Edouard Univ Strasbourg ICube Lab F-67412 Illkirch Graffenstaden France CNRS F-67412 Illkirch Graffenstaden France

ISBN: (纸本)9781479974092

Models obtained from the laws of Physics are naturally written as differential-algebraic equations (DAE) also known as descriptor models. However, the usual methodology in control consists in reducing the model to a set of ordinary equations. Remaining in the DAE word has several advantages: the reduction step is not necessary any more and the parameter dependance might be simplified. This paper is a step forward towards a control methodology that would be entirely based on DAE models. Its goal is twofold. First, the tools and methods available for DAE models are reviewed. Second, a case taken form robotics is considered. The simulation being done with Maple, a linear model is derived and transferred to Matlab for synthesis. A H-infinity controller is then synthesized and evaluated. The controlled system is then simulated with Maple.

关键词： Control systems Equations Indexes MATLAB Mathematical model numerical models control systems MATLAB numerical models Mathematical Model Control methods mathematics computing Symbolic algebra Acer Parallel robots Standing Orders Equation robotics simulating

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Straight Beams Rested on Nonlinear Elastic Foundations - Part 1 (theory, Experiments, numerical Approach)

Straight Beams Rested on Nonlinear Elastic Foundations - Par...

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International conference on Mechanics and Mechanical Engineering (MME)

作者： Frydrysek, Karel Michenkova, Sarka Nikodym, Marek VSB Tech Univ Ostrava Fac Mech Engn Dept Mech Mat 17 Listopadu 15-2172 Ostrava 70833 Czech Republic VSB Tech Univ Ostrava Dept Mech Mat Fac Mech Engn Ostrava 70833 Czech Republic VSB Tech Univ Ostrava Dept Math & Descript Geometry Ostrava 70833 Czech Republic

ISBN: (纸本)9783038353225

This paper presents theory, experiments and numerical approaches suitable for the solution of straight plane beams rested on an elastic (Winkler's) foundation, including nonlinearities. The nonlinear dependence of the reaction force on displacement in the foundation (i.e. the experimental data) can be described via bilateral linear or bilateral linear + cubic or bilateral linear + cubic + quintic approximations, or by unilateral approximation (i.e. by using the Least Squares Method). These applications lead to linear or nonlinear differential 4th-order equations. For solutions of nonlinear problems of mechanics, the Finite Difference Method (i.e. the Central Difference Method) and boundary conditions are applied. The solution and its evaluation is performed in second part of this article.

关键词： Elastic foundation Beam Experiments Finite Difference Method ( Central Differences) Nonlinearity

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Finite Memory Observers for linear time-varying systems: theory and diagnosis applications

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JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS 2014年第2期351卷 785-810页

作者： Graton, Guillaume Kratz, Frederic Fantini, Jacques Ecole Cent Marseille F-13451 Marseille 20 France Ecole Cent Marseille Lab Informat Sci & Syst F-13451 Marseille 20 France ENSI Bourges F-18020 Bourges France ENSI Bourges PRISME Lab F-18020 Bourges France Univ Orleans Polytech Orleans F-45067 Orleans France Polytech Orleans PRISME Lab F-45067 Orleans France

Fault detection and diagnosis are important issues in process engineering. Hence, a considerable interest exists in this field now from industrial practitioners as well as academic researchers, as opposed to 30 years ago. The literature on process fault diagnosis, ranging from analytical methods to artificial intelligence and statistical approaches, is largely widespread. In this paper, the modeling of the real process is known, and the state-space representation is used The properties of the Finite Memory Observer (FM()) are studied from a global point of view for the class of linear time-varying (LTV) systems with stochastic noises. The FMO performances are framed by the study of their properties, and that of their influences on diagnosis results. Fundamentally, the generation of residuals is an essential procedure in diagnosis. So, the determination of the optimal window length of the observer is resolved, and the generation of residuals for diagnosis completed. In the first part, the design of the observer and the residual generation are shown. The second part is devoted to the study of the sensitivity and robustness of the observer and of residuals generated from the observer. (C) 2013 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.

关键词： Fault detection

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Iterative Image-Domain Decomposition for Dual-Energy CT

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MEDICAL PHYSICS 2014年第6期41卷 475-476页

作者： Niu, T. Dong, X. Petrongolo, M. Zhu, L. Georgia Inst Technol Atlanta GA 30332 USA

Purpose: Dual energy CT (DECT) imaging plays an important role in advanced imaging applications due to its capability of material decomposition. Direct decomposition via matrix inversion suffers from significant degradation of image signal-to-noise ratios, which reduces clinical values of DECT. Existing denoising algorithms achieve suboptimal performance since they suppress image noise either before or after the decomposition and do not fully explore the noise statistical properties of the decomposition process. In this work, the authors propose an iterative image-domain decomposition method for noise suppression in DECT, using the full variance-covariance matrix of the decomposed images. methods: The proposed algorithm is formulated in the form of least-square estimation with smoothness regularization. Based on the design principles of a best linear unbiased estimator, the authors include the inverse of the estimated variance-covariance matrix of the decomposed images as the penalty weight in the least-square term. The regularization term enforces the image smoothness by calculating the square sum of neighboring pixel value differences. To retain the boundary sharpness of the decomposed images, the authors detect the edges in the CT images before decomposition. These edge pixels have small weights in the calculation of the regularization term. Distinct from the existing denoising algorithms applied on the images before or after decomposition, the method has an iterative process for noise suppression, with decomposition performed in each iteration. The authors implement the proposed algorithm using a standard conjugate gradient algorithm. The method performance is evaluated using an evaluation phantom (Catphan©600) and an anthropomorphic head phantom. The results are compared with those generated using direct matrix inversion with no noise suppression, a denoising method applied on the decomposed images, and an existing algorithm with similar formulation as the prop

关键词： Computed tomography Matrix theory Noise numerical linear algebra General statistical methods Spatial resolution computerised tomography conjugate gradient methods covariance matrices edge detection image denoising image resolution iterative methods least squares approximations matrix inversion medical image processing phantoms dual-energy CT image-domain decomposition noise suppression best linear unbiased estimation edge predetection Computerised tomographs Biological material, e.g. blood, urine Haemocytometers Digital computing or data processing equipment or methods, specially adapted for specific applications Image data processing or generation, in general Image enhancement or restoration, e.g. from bit-mapped to bit-mapped creating a similar image Medical imaging Medical image noise Computed tomography Medical image reconstruction Medical image spatial resolution Medical X-ray imaging Spatial resolution Matrix inversion Medical image smoothing Density measurement

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Outer Bound Estimations for the Spectral Radii of Interval Matrices 18

Outer Bound Estimations for the Spectral Radii of Interval M...

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18th International conference on System theory, Control and Computing (ICSTCC)

作者： Matcovschi, Mihaela-Hanako Pastravanu, Octavian Voicu, Mihail Tech Univ Gheorghe Asachi Iasi Dept Automat Control & Appl Informat Blvd Mangeron 27 Iasi 700050 Romania

ISBN: (纸本)9781479946013

The paper proposes two estimation methods for the spectral radius of a complex interval matrix. These methods exploit different properties of the interval matrix and construct distinct numerical approaches, so that their results dispute, from case to case, the precision of the estimation. This complementarity of the two methods recommends their parallel use in practical applications, allowing the selection of the best outer approximation for the spectral radius. The paper also discusses the algorithmic implementations by using MATLAB compatible software environments. The considered case studies illustrate (i) the operation of the two methods;(ii) the dependence of the accuracy of each method on the concrete entries of the interval matrix, and, implicitly, the usefulness of comparisons between the results provided by both presented methods.

关键词： interval matrix spectral radius linear and bilinear matrix inequalities

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3rd International conference on numerical Analysis and Optimization: theory, methods, applications and Technology Transfer, NAOIII 2014

3rd International Conference on Numerical Analysis and Optim...

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3rd International conference on numerical Analysis and Optimization: theory, methods, applications and Technology Transfer, NAOIII-2014

ISBN: (纸本)9783319176888

The proceedings contain 13 papers. The special focus in this conference is on numerical Analysis and Optimization. The topics include: A conic representation of the convex hull of disjunctive sets and conic cuts for integer second order cone optimization;runge-kutta methods for ordinary differential equations;a positive barzilai-borwein-like stepsize and an extension for symmetric linear systems;necessary optimality conditions for the control of partial integro-differential equations;an aid to formulating and solving optimization problems;dynamics characterization based geo-statistical prior sampling;solving multiscale linear programs using the simplex method in quadruple precision;real and integer extended rank reduction formulas and matrix decompositions;distributed block coordinate descent for minimizing partially separable functions;models for optimization of power systems and on chubanov’s method for solving a homogeneous inequality system.

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methods for the Quick Analysis of Micro-chaos 12

Methods for the Quick Analysis of Micro-chaos

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12th International conference on Dynamical Systems-theory and applications (DSTA)

作者： Gyebroszki, Gergely Csernak, Gabor Budapest Univ Technol & Econ Dept Appl Mech Muegyetem Rkp 5 H-1111 Budapest Hungary HAS BUTE Res Grp Dynam & Machines Vehicles H-1111 Budapest Hungary

ISBN: (纸本)9783319082653

Micro-chaos is a phenomenon when sampling, round-off and processing delay (shortly, digital effects) lead to chaotic oscillations with small amplitude. In previous works [1], the so-called micro-chaos maps of various digitally controlled unstable linear mechanical systems were derived and the possibility of the coexistence of several disconnected attractors was highlighted. The typical size of these attractors is usually negligible from the practical point of view, but the distance of the farthest attractor from the desired state can be rather large. This is why the phenomenon of micro-chaos can be the source of significant control error. In this paper, a set of numerical methods (e.g. cell mapping techniques for the exploration of the phase-space structure) is assembled in order to create a toolkit for the quick analysis of micro-chaotic behaviour. The elaborated methods are tested on models of PD-controlled unstable systems and the practically important characteristics of chaotic behaviour are determined.

关键词： numerical methods

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Time-Dependent Behavior of Queueing Delay in GI/M/1/K-type Model with N-policy: Analytical Study with applications to WSNs

Time-Dependent Behavior of Queueing Delay in <i>GI</i>/<i>M<...

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21st International conference on Analytical and Stochastic Modelling Techniques and applications (ASMTA)

作者： Kempa, Wojciech M. Silesian Tech Univ Inst Math PL-44100 Gliwice Poland

ISBN: (纸本)9783319082196;9783319082189

The transient queueing delay distribution in the GI/M/1/Ktype model with the N-policy is investigated. After finishing each busy period the service is being initialized simultaneously with the Nth packet arrival occurrence. Using the approach based on the idea of embedded Markov chain, the formula of total probability, renewal theory and linear algebra, the compact-form representation for the Laplace transform of the tail of delay distribution is obtained. The results can be useful in modeling the operation of wireless sensor networks (WSNs) with energy saving mechanism based on "queued" waking up of nodes. A network-motivated numerical example is attached.

关键词： Finite-buffer queue N-policy Queueing delay Transient state Wireless sensor network (WSN)

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Experiments with GPU-Acceleration for Solving a Radiative Transfer Problem

Experiments with GPU-Acceleration for Solving a Radiative Tr...

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14th International conference on Computational Science and Its applications (ICCSA)

作者： Vasconcelos, Paulo B. Marques, Osni Univ Porto Rua Campo Alegre 823 P-4100 Oporto Portugal CMUP Oporto Portugal Lawrence Berkeley Natl Lab Berkeley CA USA

ISBN: (纸本)9783319091471;9783319091464

High performance computing systems are increasingly incorporating the computational power provided by accelerators, especially GPUs. With the programmability of GPUs greatly facilitated by OpenCL or NVIDIA's CUDA, with support for full double precision on GPUs, many challenging problems are benefiting from these processing units. It is well-known that memory latency is the speed limiting factor on GPUs. To hide memory latency, kernel instances must be executed in parallel on the same core, making sparse data more difficult to deal with than dense data. In this work we examine the numerical solution of a radiative transfer problem. We show that integral problem formulations relying on sparse linear algebra computations can benefit from the computing power of such devices, achieving an average speedup of 50x when compared to a representative CPU implementation.

关键词： GPU implementation integral operators sparse linear iterative methods

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6th International conference on Finite Difference methods, theory and applications, FDM 2014

6th International Conference on Finite Difference Methods, T...

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6th International conference on Finite Difference methods, FDM 2014

ISBN: (纸本)9783319202389

The proceedings contain 48 papers. The special focus in this conference is on Finite Difference methods, theory and applications. The topics include: Simulation of flow in fractured poroelastic media;a transparent boundary condition for an elastic bottom in underwater acoustics;operator semigroups for convergence analysis;on extension of asymptotic comparison principle for time periodic reaction-diffusion-advection systems with boundary and internal layers;the finite difference method for boundary value problem with singularity;superconvergence of some linear and quadratic functionals for higher-order finite elements;time step for numerically solving parabolic problems;recent advances in numerical solution of HJB equations arising in option pricing;applications of numerical methods for stochastic controlled switching diffusions with a hidden markov chain;difference schemes for delay parabolic equations with periodic boundary conditions;some results of FEM schemes analysis by finite difference method;application of finite difference TVD methods in hypersonic aerodynamics;finite difference equations for neutron flux and importance distribution in 3D heterogeneous reactor;matrix-free iterative processes for implementation of implicit runge-kutta methods;simulation of technogenic and climatic influences in permafrost for northern oil fields exploitation;iterative implicit methods for solving nonlinear dynamical systems;modeling textile fabric used in pest control with a 3 scale domain decomposition method;the theory and applications of the SMIF method for correct mathematical modeling of the incompressible fluid flows and determination of the time-dependent thermal conductivity in the heat equation with spacewise dependent heat capacity.

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