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31st Chinese Control And Decision conference (CCDC)

作者： Xu, Chuanchuan Thou, Bin Hou, Mingzhe Harbin Inst Technol Ctr Control Theory & Guidance Technol Harbin 150001 Peoples R China

ISBN: (纸本)9781728101057

This paper studies the low-pass filter (LPF) design in the delayed output feedback control of linear time-varying systems. In the case of linear time-invariant systems, the safe implementation of the distributed delay (integral terms) needs to introduce an LPF in the control loop and the LPF can be designed by using the pole assignment method. However, the parameters of LPF in linear time-varying systems are time-varying and the existing design methods are not applicable. This paper provides a new method to design the LPF for time-varying systems. The designed LPFs are such that, if the closed-loop system without LPF is uniformly asymptotically stable, then the closed-loop system with LPF is also uniformly asymptotically stable, while the later is robust with respect to approximated numerical implementation. Finally, simulations are carried out on a magnetic attitude control system and the results verify the effectiveness of the methods proposed in this paper.

关键词： Low-pass Filter Delayed Output Feedback Time-delay Systems Spacecraft Attitude Control Magnetic Attitude Control

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The Maximum Localization Error Bound of Distributed Array for Focused Energy Delivery in Precision Electronic Warfare

The Maximum Localization Error Bound of Distributed Array fo...

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International conference on Computer and Communications (ICCC)

作者： Zhongping Yang Shuning Yang Jianyun Zhang Qingsong Zhou College of Electronic Engineering National University of Defense Technology Hefei China

ISBN: (数字)9781728186351

ISBN: (纸本)9781728186368

Focused energy delivery is the core technology for bringing energy to a specific area by the ultra-sparse array. This paper mainly focuses on one of its typical applications: precision electronic warfare (PREW), and analyzes the influence of localization errors caused by each nodes on focused energy delivery. According to the model proposed, we obtain the analytical expressions of the objective function appropriately and introduce the localization errors. Under the reasonable assumption based on the theory of algebra and geometry, the maximum localization error bound is concluded that it should be less than 1/8 of the carrier wavelength. Finally, numerical results demonstrate the correctness of the maximum localization error bound derived, and indicate the impact of different errors on the model.

关键词： Location awareness Geometry Electronic warfare numerical simulation linear programming Robustness numerical models

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Faster randomized infeasible interior point methods for tall/wide linear programs 20

Faster randomized infeasible interior point methods for tall...

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Proceedings of the 34th International conference on Neural Information Processing Systems

作者： Agniva Chowdhury Palma London Haim Avron Petros Drineas Department of Statistics Purdue University West Lafayette IN ORIE Department Cornell University Ithaca NY School of Mathematical Sciences Tel Aviv University Tel Aviv Israel Department of Computer Science Purdue University West Lafayette IN

ISBN: (纸本)9781713829546

linear programming (LP) is used in many machine learning applications, such as ℓ1-regularized SVMs, basis pursuit, nonnegative matrix factorization, etc. Interior Point methods (IPMs) are one of the most popular methods to solve LPs both in theory and in practice. Their underlying complexity is dominated by the cost of solving a system of linear equations at each iteration. In this paper, we consider infeasible IPMs for the special case where the number of variables is much larger than the number of constraints (i.e., wide), or vice-versa (i.e., tall) by taking the dual. Using tools from Randomized linear algebra, we present a preconditioning technique that, when combined with the Conjugate Gradient iterative solver, prov-ably guarantees that infeasible IPM algorithms (suitably modified to account for the error incurred by the approximate solver), converge to a feasible, approximately optimal solution, without increasing their iteration complexity. Our empirical evaluations verify our theoretical results on both real and synthetic data.

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A General Test for the linear Structure of Covariance Matrices of Gaussian Populations

A General Test for the Linear Structure of Covariance Matric...

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IEEE International conference on Acoustics, Speech and Signal Processing

作者： Yu-Hang Xiao David Ramirez Peter J. Schreier Signal and System Theory Group University of Paderborn Germany Dept. of Signal Theory and Communications Universidad Carlos III de Madrid Spain

ISBN: (数字)9781509066315

ISBN: (纸本)9781509066315;9781509066322

This paper addresses the problem of testing whether a covariance matrix can be expressed by an unknown linear combination of a set of known matrices or by another unknown linear combination of a set of different, but known, matrices. This problem is of interest in a wide range of real-world applications, such as radar, sonar, and spectrum sensing. We study the problem under the Gaussian assumption and derive the generalized likelihood ratio test (GLRT). Since there is no general closed-form solution for the maximum likelihood (ML) estimates of the covariance matrices, which are required for the GLRT, we resort to a powerful inverse iteration algorithm. Finally, an example, along with numerical results, is given to illustrate the methodology.

关键词： covariance matrices iterative methods maximum likelihood estimation signal detection

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Nonlinear static FE-analysis of smart piezolaminated FGM shells at finite rotations 7th

Nonlinear static FE-analysis of smart piezolaminated FGM she...

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7th International conference on Structural Engineering, Mechanics and Computation (SEMC)

作者： Schmidt, R. Rao, M. N. Schroeder, K-U Rhein Westfal TH Aachen Inst Struct Mech & Lightweight Design Aachen Germany

ISBN: (纸本)9780429426506;9781138386969

The purpose of this work is to investigate the static behavior of piezolaminated thin-walled functionally graded material (FGM) and composite shells in the range of geometrically linear and nonlinear deformations. A power law type variation of FGM material properties is adopted. Finite rotations and full nonlinear terms in the geometrically nonlinear strain-displacement relations are considered in the framework of FOSD theory to derive the variational formulation. In order to enrich the behavior and reliability of the four-node piezolaminated composite shell element, an assumed natural strain (ANS) method for the shear strains, an enhanced assumed strain (EAS) method for the membrane strains and an enhanced assumed gradient (EAG) method for the electric field is encompassed. Predictive capabilities of the proposed numerical formulation are demonstrated using several numerical examples, in particular shells integrated with piezolayers in both sensory and actuator applications in the range of linear and geometrically nonlinear deformations. numerical simulations with the present model and other simplified nonlinear models available in literature are performed and compared, demonstrating the worthiness of the present method in large deflection analysis. Additionally, the present results are compared with those obtained by Abaqus by modeling the master structure using the shell S8R element and piezo-layers using C3D20RE solid elements.

关键词： numerical methods

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Stresses in a pressurised parabolic ogival toroidal vessel 7th

Stresses in a pressurised parabolic ogival toroidal vessel

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7th International conference on Structural Engineering, Mechanics and Computation (SEMC)

作者： Enoma, N. Zingoni, A. Univ Cape Town Dept Civil Engn Struct Engn & Mech Grp Cape Town South Africa

ISBN: (纸本)9780429426506;9781138386969

A closed-form analytical solution is presented for the complete determination of the stress state and deformations within parabolic ogival toroidal vessels under internal pressure. linear theory-equations for the vessels are formulated on the basis of the theory of thin-shells of revolution. The equations are simplified and systematically solved using the general strategy of Zingoni (2018), in which the Geckeler approximations are adopted, and the membrane solution is superimposed with an approximate bending solution of the bending-theory equations. The accuracy of the developed solution algorithm is demonstrated through a numerical example by comparing results with those from finite element analysis. Excellent agreement is achieved throughout the vessel. The accuracy of the developed method demonstrates the validity of Geckeler approximations even in the anticlastic surfaces of shells of revolution.

关键词： numerical methods

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Control of non-linear systems based on interval observer design

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IET CONTROL theory AND applications 2018年第4期12卷 543-548页

作者： He, Zhongwei Xie, Wei Jiangxi Univ Finance & Econ Sch Informat Technol Nanchang 330013 Jiangxi Peoples R China South China Univ Technol Coll Automat Sci & Technol Guangzhou 510641 Guangdong Peoples R China

This study develops a Luenberger-like interval observer design methodology for a class of non-linear systems with bounded uncertainties. First, a simple procedure is given to find a positive representation that provides a method to guarantee the existence of observer gain by means of the matrix theory. Then, based on interval observer design, the gain of feedback controllers for non-linear systems is presented in terms of a linear matrix inequality formulation. Finally, a numerical example is provided to demonstrate the efficiency of the proposed approach.

关键词： bounded uncertainties control system synthesis feedback linear algebra (numerical analysis) Control system analysis and synthesis methods Luenberger-like interval observer design methodology observers linear matrix inequality formulation LMI Simulation, modelling and identification nonlinear control systems observer gain nonlinear systems control Nonlinear control systems feedback controllers uncertain systems linear matrix inequalities positive representation

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On solving the geometrically nonlinear and linear problems of transverse bending of a hinged fixing sandwich plate with transversally soft core 12

On solving the geometrically nonlinear and linear problems o...

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12th International conference on Mesh methods for Boundary - Value Problems and applications

作者： Makarov, M. V. Badriev, I. B. Buyanov, V. Yu Smirnova, E. V. Kazan Fed Univ 18 Kremlyovskaya St Kazan 420008 Russia Kazan Natl Res Tech Univ 10 K Marks St Kazan 420111 Russia

The study of the problem of finding the stress-strain state of a sandwich plate with a transversally soft core under the action of a transverse load in a one-dimensional geometrically nonlinear formulation was carried out. A generalized formulation of the problem in the form of an operator equation is proposed. The properties of the operator of the equation are established, which make it possible to use the general results of the theory of monotone operators in the study of correctness. To find the stress-strain state of the plate, a two-layer iterative method is proposed with lowering the nonlinearity on the lower layer. A finite-dimensional approximation of the problem and the iterative method was carried out. The convergence of finite-dimensional approximations and the iterative method has been studied. For the numerical implementation of the proposed approximate methods, a software package has been developed in the Matlab environment. Based on it, numerical experiments were carried out.

关键词： Iterative methods

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On transmutation operators and neumann series of bessel functions representations for solutions of linear higher order differential equations

On transmutation operators and neumann series of bessel func...

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International Scientific conference of Modern methods and Problems of Operator theory and Harmonic Analysis and Their applications, OTHA 2018

作者： Gómez, Flor A. Kravchenko, Vladislav V. Departamento de Matemáticas Cinvestav Unidad Querétaro Juriquilla Mexico Regional Mathematical Center of Southern Federal University Rostov-on-Don Russia

ISBN: (纸本)9783030267476

A new representation for solutions of linear higher order ordinary differential equations with a spectral parameter is obtained in terms of Neumann series of Bessel functions. The result is based on a Fourier-Legendre series representation for the Borel transform of the solution with respect to the spectral parameter. Estimates for the coefficients and for the convergence of the representation are derived. numerical illustrations of the applicability of the obtained formulae are presented. © Springer Nature Switzerland AG 2019.

关键词： Bessel functions

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numerical Analysis for Applied Science, Second Edition 2

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丛书名： Pure and applied mathematics

2019年

作者： Myron B. Allen Eli L. Isaacson

ISBN: (数字)9781119245476

ISBN: (纸本)9781119245469

Pragmatic and Adaptable Textbook Meets the Needs of Students and Instructors from Diverse Fields numerical analysis is a core subject in data science and an essential tool for applied mathematicians, engineers, and physical and biological scientists. This updated and expanded edition of numerical Analysis for Applied Science follows the tradition of its precursor by providing a modern, flexible approach to the theory and practical applications of the field. As before, the authors emphasize the motivation, construction, and practical considerations before presenting rigorous theoretical analysis. This approach allows instructors to adapt the textbook to a spectrum of uses, ranging from one-semester, methods-oriented courses to multi-semester theoretical courses. The book includes an expanded first chapter reviewing useful tools from analysis and linear algebra. Subsequent chapters include clearly structured expositions covering the motivation, practical considerations, and theory for each class of methods. The book includes over 250 problems exploring practical and theoretical questions and 32 pseudocodes to help students implement the methods. Other notable features include: A preface providing advice for instructors on using the text for a single semester course or multiple-semester sequence of courses Discussion of topics covered infrequently by other texts at this level, such as multidimensional interpolation, quasi-Newton methods in several variables, multigrid methods, preconditioned conjugate-gradient methods, finite-difference methods for partial differential equations, and an introduction to finite-element theory New topics and expanded treatment of existing topics to address developments in the field since publication of the first edition More than twice as many computational and theoretical exercises as the first edition. numerical Analysis for Applied Science, Second Edition provides an excellent foundation for graduate and advanced undergraduate cours

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