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Faster and more accurate computation of the field of values boundary for n by n matrices

LINEAR & MULTILINEAR ALGEBRA 2014年第5期62卷 554-567页

作者： Uhlig, Frank Auburn Univ Dept Math & Stat Auburn AL 36849 USA

We revisit an earlier idea of Marcus and Pesce from 1987 for generating fields of values of by matrices via 2 by 2 matrix compressions and their easily constructed elliptical field of values. This approach is used to reduce the cost of finding the FOV boundary curve of a matrix and makes it more accurate at the same time. The new algorithm succeeds by using fewer eigenanalyses and constructing 2 by 2 matrix compression ellipses of for approximating instead of only eigenanalyses. An application to verify a counterexample to the Zemanek Conjecture for companion matrices of monic polynomials and their normalized derivatives in and , respectively, in dimension 4 is given.

关键词： MATLAB code numerical algorithm matrix compression numerical range matrix pencil extreme eigenvalues field of values ellipse

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An inverse problem of Bilayer textile thickness determination in dynamic heat and moisture transfer

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APPLICABLE ANALYSIS 2014年第3期93卷 445-465页

作者： Xu, Dinghua Wen, Lei Xu, Boxi Zhejiang Sci Tech Univ Dept Math Zhejiang 310018 Peoples R China Fudan Univ Coll Math Sci Shanghai 200433 Peoples R China

An inverse problem of bilayer textile thickness determination in dynamic heat and moisture transfer is presented satisfying the heat-moisture comfort level of human body. Heat and mass transfer law in bilayer textiles is displayed by proving the existence and uniqueness of solution to the coupled partial differential equations with initial-boundary value conditions. The finite difference method is employed to derive the numerical solution to partial differential equations. The regularized solution of the inverse problem is reformulated into solving function minimum problem through the Tikhonov regularization method. The golden section method is applied to solve the direct search problem and achieve the optimal solution to the inverse problem. numerical algorithm and its numerical results provide theoretical explanation for textile materials research and development.

关键词： inverse problems of thickness determination numerical algorithm well-posedness partial differential equations of parabolic type bilayer textile materials regularized solution

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Combined state and least squares parameter estimation algorithms for dynamic systems

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APPLIED MATHEMATICAL MODELLING 2014年第1期38卷 403-412页

作者： Ding, Feng Jiangnan Univ Minist Educ Key Lab Adv Proc Control Light Ind Wuxi 214122 Peoples R China Jiangnan Univ Control Sci & Engn Res Ctr Wuxi 214122 Peoples R China

The control theory and automation technology cast the glory of our era. Highly integrated computer chip and automation products are changing our lives. Mathematical models and parameter estimation are basic for automatic control. This paper discusses the parameter estimation algorithm of establishing the mathematical models for dynamic systems and presents an estimated states based recursive least squares algorithm, and the states of the system are computed through the Kalman filter using the estimated parameters. A numerical example is provided to confirm the effectiveness of the proposed algorithm. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Dynamic system numerical algorithm Least squares Parameter estimation Recursive identification State space model

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Data assimilation problems and stabilization with respect to unstable manifolds

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RUSSIAN JOURNAL OF numerical ANALYSIS AND MATHEMATICAL MODELLING 2014年第1期29卷 47-55页

作者： Kornev, Andrei A. Moscow MV Lomonosov State Univ Dept Mech & Math Moscow 119992 Russia

A new method solving the initial data assimilation problem is proposed in the paper. The method is based on the results of the theory of global attractors. The numerical algorithm is formulated, its convergence is justified, analysis of computational formulas is performed. It is shown that the method is equivalent in some sense to the construction of nontrivial trajectories of a global attractor and also to solving the stabilization problem in terms of projections onto an unstable manifold. This result allows us to consolidate the theory of iterative methods for stabilization to unstable trajectories of the hyperbolic type based on the properties of local invariant stable and unstable manifolds.

关键词： Initial data assimilation stabilization global attractor numerical algorithm

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Coolant Flow Estimation in Natural Circulation BWR

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ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS 2014年第17期36卷 1949-1957页

作者： Valle-Hernandez, J. Espinosa-Paredes, G. Morales-Sandoval, J. B. Univ Nacl Autonoma Mexico Mexico City 04510 DF Mexico Univ Autonoma Metropolitana Iztapalapa Area Ingn Recursos Energet Mexico City 09340 DF Mexico

This work presents the design and implementation of an advanced controller in real time for the estimation of coolant flows through fuel assemblies about standard neutron flux strings of a boiling water reactor (BWR) reactor core cooled by natural circulating water. During all operations of a natural circulating BWR, the fuel assembly's coolant flow is one of the main variables to consider. The goal of this advanced controller is to reduce penalties associated with operation limits established due to coolant flow uncertainties. The design of the controller was based on the theory of an extended Kalman filter. The estimator flow uses the equivalent electrical model, which was developed from the analogies between electrical current and voltage with coolant flows and pressure drops. Results obtained from computer simulations indicate that the best estimations of the total core flow are possible for the natural circulating BWR.

关键词： coolant flow economic simplified boiling water reactor Kalman filter natural circulation numerical algorithm simulations

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Determination of Radiation Reflection and Transmission Operators in a Slab

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COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2014年第3期54卷 546-552页

作者： Muradyan, M. G. Armenian State Univ Econ Yerevan 0025 Armenia

In the framework of a discrete radiative transfer model, a method is proposed for finding the reflection and transmission operators in the conservative case.

关键词： radiative transfer reflection and transmission operators numerical algorithm

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On the development of a wake vortex in inviscid flow

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COMPUTATIONAL MATHEMATICS AND MATHEMATICAL PHYSICS 2014年第1期54卷 172-176页

作者： Belotserkovskii, O. M. Belotserkovskaya, M. S. Denisenko, V. V. Eriklintsev, I. V. Kozlov, S. A. Oparina, E. I. Troshkin, O. V. Fortova, S. V. Russian Acad Sci Inst Comp Aided Design Moscow 123056 Russia

The evolution of an initial perturbation in an axisymmetric subsonic normal inviscid gas flow through a pipe is directly simulated. The basic (unperturbed) flow has a zero radial velocity component, while its axial velocity component (along the axis of symmetry) increases or decreases linearly with the radius. The perturbation is specified as a swirl (rotation about the axis) with a positive or negative velocity vanishing on the central axis and the lateral surface. Irrespective of its direction, the swirl gives rise to a steady-state vortex carried by the flow. It shape is spherical (contiguous to the rotation axis) or circular (sliding along the impermeable lateral surface).

关键词： swirling normal gas flow development of spherical or circular vortices mathematical simulation direct numerical simulation numerical algorithm

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Conditional Multidimensional Parameter Identification with Asymmetric Correlated Losses of Estimation Errors 21

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21st International Conference on Neural Information Processing (ICONIP)

作者： Kulczycki, Piotr Charytanowicz, Malgorzata Polish Acad Sci Syst Res Inst Warsaw Poland John Paul II Catholic Univ Lublin Lublin Poland

ISBN: (纸本)9783319126401

This paper is dedicated to the problem of the estimation of a vector of parameters, as losses resulting from their under- and overestimation are asymmetric and mutually correlated. The issue is considered from an additional conditional aspect, where particular coordinates of conditioning variables may be continuous, binary, discrete or categorized (ordered and unordered). The final result is an algorithm for calculating the value of an estimator, optimal in sense of expectation of losses using a multidimensional asymmetric quadratic function, for practically any distributions of describing and conditioning variables.

关键词： parameters' vector identification conditional factors Bayes approach asymmetric loss function distribution free method numerical algorithm

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Computer Assisted Design to Develop Functional Device and Modules for Wireless Systems

Computer Assisted Design to Develop Functional Device and Mo...

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Asia-Pacific Microwave Conference Proceedings

作者： Takei, Ken Ohnishi, Masami Hitachi Ltd Hitachi Res Lab Tokyo Japan

ISBN: (纸本)9784902339314

Computer assisted design in conceptional phase is very useful for not only reducing development cost, especially human resource cost, but also creating a novel function. Since the performances of microwave devices and circuits can be precisely simulated by using Maxwell's equation and electrical circuit theory, conceptional design by computer is very useful for these devices and circuits. This report explains the technologies for automatically generating an antenna structure and a circuit configuration that satisfies the specifications of various wireless systems. These technologies enable us to provide actual products without the knowledge of a senior antenna engineer who has had a very tough and long training. Our design technologies arc categorized into brute-force methods for randomly generating antenna structures or circuit configurations and calculating their electromagnetic performances or RE characteristics, i.e., power consumption, distortion, and power conversion efficiency. If the performances satisfy the given specifications, these structures or circuit configurations become the candidates of the device or circuit to be designed. Due to the drastic speeding-up of CPU chips and the continuous improvement of numerical algorithms, we have discovered special structures or configurations that reveal the typical functions for various wireless systems. Prototypes of both devices and circuits that were obtained by using our technologies are introduced, and the typical performances for applications of wireless systems are demonstrated.

关键词： antenna power supply numerical algorithm wireless system

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An inverse eigenvalue problem of the theory of optical waveguides

An inverse eigenvalue problem of the theory of optical waveg...

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International Conference on Days on Diffraction (DD)

作者： Karchevskii, E. M. Spiridonov, A. O. Kazan Fed Univ Dept Appl Math Kazan Russia

ISBN: (纸本)9781479966998

We present a new method for calculation of permittivities of dielectric materials using optical fiber's propagation constants measurements. Our numerical algorithm is based on approximate solution of a nonlinear nonselfadjoint inverse eigenvalue problem for a system of weakly singular integral equations. We prove that it is enough to measure propagation constants of fundamental eigenmode only at two frequencies for reconstruction of dielectric constants of core and cladding of a waveguide.

关键词： approximation theory eigenvalues and eigenfunctions integral equations inverse problems optical fibre cladding optical fibre testing permittivity approximate solution dielectric constants dielectric materials fundamental eigenmode nonlinear nonselfadjoint inverse eigenvalue problem numerical algorithm optical fiber propagation constant measurements optical waveguide theory singular integral equations waveguide cladding waveguide core Eigenvalues and eigenfunctions Nonlinear optics Optical waveguide theory Permittivity Propagation constant Splines (mathematics) Dielectric constant Optical waveguide theory Eigenfunctions Propagation constant singular integral equations dielectric materials Optical fiber testing optical fibre cladding Approximation Theory Nonlinear optics Integral equations Inverse method dielectric properties

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