This paper deals with the synthesis of a suboptimal controller based on the solution of the algebraic Riccati equation (ARE). The numerical procedure for obtaining the solution is presented. In applications the contro...
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This paper deals with the synthesis of a suboptimal controller based on the solution of the algebraic Riccati equation (ARE). The numerical procedure for obtaining the solution is presented. In applications the controlled system parameters often differ from the ones used in the ARE. In this case the optimality of the control system and even its stability are questionable. Therefore, it would be very useful to design an adaptive linear suboptimal controller Such a controller should be able to detect changes in the system parameters and adjust its parameters. (C) 2006 Journal of Mechanical Engineering. All rights reserved.
An efficient algorithm for L ∞ -norm calculations, implemented in the SLICOT Library, is described and compared with other available algorithms. The algorithm exploits the Hamiltonian structure of the computational p...
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An efficient algorithm for L ∞ -norm calculations, implemented in the SLICOT Library, is described and compared with other available algorithms. The algorithm exploits the Hamiltonian structure of the computational problem and offers generality and flexibility. Continuous- and discrete-time, standard as well as generalized systems are addressed. Extensive comparisons with other L ∞ -norm solvers show that the generalpurpose SLICOT solver is the most efficient one, especially for standard continuous-time problems.
The present wok provides a comparative study on the numerical solution of the dynamic population balance equation (PBE) in batch particulate processes undergoing simultaneous particle aggregation, growth and nucleatio...
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The present wok provides a comparative study on the numerical solution of the dynamic population balance equation (PBE) in batch particulate processes undergoing simultaneous particle aggregation, growth and nucleation. The general PBE was numerically solved using three different techniques namely, the Galerkin on finite elements method (GFEM), the generalized method of moments (GMOM) and stochastic Monte Carlo simulations (MC). numerical simulations were carried out over a wide range of variation of particle aggregation and growth rate models.
This paper concerns an optimal control problem defined on a class of switched mode hybrid dynamical systems. Such systems change modes whenever the state intersects certain surfaces that are defined in the state space...
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This paper concerns an optimal control problem defined on a class of switched mode hybrid dynamical systems. Such systems change modes whenever the state intersects certain surfaces that are defined in the state space. These switching surfaces are parameterized by a finite dimensional vector called the switching parameter. The optimization problem we consider is to minimize a given cost-functional with respect to the switching parameter under the assumption that the initial state of the system is not completely known. Instead, we assume that the initial state can be anywhere in a given set. We will approach this problem by minimizing the worst possible cost over the given set of initial states using results from minimax optimization. The results are then applied in order to solve a navigation problem in mobile robotics.
A method is proposed for estimating both the weights and the state of a multiple model system with one common state vector. In this system, the weights are related to the activation of each individual model. For the r...
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A method is proposed for estimating both the weights and the state of a multiple model system with one common state vector. In this system, the weights are related to the activation of each individual model. For the resulting nonlinear estimation problem a method is developed that efficiently decomposes the total problem into two separate parts, one for estimating the model weights and one for estimating the state. The method has been validated on a component, actuator and sensor fault detection and identification problem for a linearized model of an aircraft.
We consider the following abstraction of competing publications. There are n players vying for the attention of the audience. The attention of the audience is abstracted by a single slot which holds, at any given time...
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ISBN:
(纸本)9781595934529
We consider the following abstraction of competing publications. There are n players vying for the attention of the audience. The attention of the audience is abstracted by a single slot which holds, at any given time, the name of the latest release. Each player needs to choose, ahead of time, when to release its product, and the goal is to maximize the amount of time its product is the latest release. Formally, each player i chooses a point xi ∈ [0,1], and its payoff is the distance from its point xi to the next larger point, or to 1 if xi is the largest. For this game, we give a complete characterization of the Nash equilibrium for the two-player, continuous-action game, and, more important, we give an efficient approximation algorithm to compute numerically the symmetric Nash equilibrium for the n-player game. The approximation is computed via a discrete-action version of the game. In both cases, we show that the (symmetric) equilibrium is unique. Our algorithmic approach to the n-player game is non-standard in that it does not involve solving a system of differential equations. We believe that our techniques can be useful in the analysis of other timing games.
We present several numerical algorithms for six-degree-of-freedom rigid-body registration of line fiducial objects to their marks in cross-sectional planar images, such as those obtained in CT and MRI, given the corre...
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We present several numerical algorithms for six-degree-of-freedom rigid-body registration of line fiducial objects to their marks in cross-sectional planar images, such as those obtained in CT and MRI, given the correspondence between the marks and line fiducials. The area of immediate application is frame-based stereotactic procedures, such as radiosurgery and functional neurosurgery. The algorithms are also suitable to problems where the fiducial pattern moves inside the imager, as is the case in robot-assisted image-guided surgical applications. We demonstrate the numerical methods on clinical CT images and computer-generated data and compare their performance in terms of robustness to missing data, robustness to noise, and speed. The methods show two unique strengths: (1) They provide reliable registration of incomplete fiducial patterns when up to two-thirds of the total fiducials are missing from the image;and (2) they are applicable to an arbitrary combination of line fiducials without algorithmic modification. The average speed of the fastest algorithm is 0.3236 s for six fiducial lines in real CT data in a Matlab implementation. (C) 2002 American Association of Physicists in Medicine.
An overview of the JMSL 2.5 numerical library, the software product of the Visual Numerics, Inc., is given. There is a package of Java classes developed especially to support scientific computations. The package offer...
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ISBN:
(纸本)9788096926428
An overview of the JMSL 2.5 numerical library, the software product of the Visual Numerics, Inc., is given. There is a package of Java classes developed especially to support scientific computations. The package offers well-known numerical algorithms of linear algebra, optimization, statistics, and lot of other ones covering various fields including 2-D graphics. The paper discusses the JMSL numerical capabilities in general overview and provides some issues focused on possibilities of that package to solve problems in computational economics particularly.
A coupled mode system is derived to investigate a three-wave parametric instability leading to energy transfer between co-propagating laser beams crossing in a plasma flow. The model includes beams of finite width ref...
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A coupled mode system is derived to investigate a three-wave parametric instability leading to energy transfer between co-propagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a Crank-Nicholson-type scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differential-algebraic system is solved using an adaptive, backward-differencing method coupled with Newton's method. A numerical study is conducted in two dimensions that compares the intensity gain of the fully time-dependent coupled mode system with the gain computed under the further assumption of a strongly damped ion acoustic response. The results demonstrate a time-dependent gain suppression when the beam diameter is commensurate with the velocity gradient scale length. The gain suppression is shown to depend on time-dependent beam refraction and is interpreted as a time-dependent frequency shift. (c) 2005 Elsevier Inc. All rights reserved.
A Hill-type incremental formulation for two-phase composites was recently proposed by Doghri and Ouaar [Int. J. Solids Struct. 40(7) (2003) 168 1]. We present a slightly improved version of the formulation and test it...
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A Hill-type incremental formulation for two-phase composites was recently proposed by Doghri and Ouaar [Int. J. Solids Struct. 40(7) (2003) 168 1]. We present a slightly improved version of the formulation and test it for non-spherical inclusions. The formulation enables the simulation of unloading and cyclic loadings. Two homogenization schemes are implemented: Mori-Tanaka (M-T) and an interpolative double-inclusion model (D-I). Two plasticity models which can be used for any phase are implemented: classical J(2) elasto-plasticity and Chaboche's model with non-linear kinematic and isotropic hardenings. All rate equations are discretized in time using implicit generalized mid-point schemes. A two-scale procedure for the simulation of composite structures is developed: a finite element (FE) program at macro-scale linked to the homogenization module at micro-scale. An extensive validation of the homogenization predictions against experimental data and direct unit cell FE simulations is conducted for several composite systems. (C) 2004 Elsevier Ltd. All rights reserved.
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