利用矩阵的广义逆求线性方程组的解

在线性代数中,解齐次线性方程组最常用的方法是消元法以一般解或以基础解系的线性组合的形式给出通解,但并没有给出以系数矩阵显示的通解表达式;矩阵的广义逆理论虽然能解决上述困难,但不易实际求解。本文给出与矩阵的广义逆有关的几个定理,给出解方程组的一种方法。1基本概念定义1.1设A为m×n矩阵。如果n×m矩阵G满足AGA=A,称G为A的一个广义逆。定义1.2设m×n矩阵A的秩为r,若存在m阶可逆矩阵P和n阶可逆矩阵Q使000A=P???Er???Q则称此式为A的一个PSQ分解式。(显然,上述分解式一般不唯一)。定义1.3称主对角线上的元素全为1的上三角形…     

基于DRNN神经网络的非线性系统的广义预测控制

提出一种针对一类可分非线性系统的广义预测控制算法。首先利用对角回归型神经网络（Diagonal Recurrent Neura Network,简称DRNN）逼近非线性子系统,线性子系统的模型采用受控自回归积分滑动平均模型（CARIMA）,从而建立了一种适合于非线性系统的广义预测模型。在该算法中引入柔化系数矩阵,避免矩阵求逆的计算,减少了在线计算量。仿真结果表明,该广义预测控制算法具有响应速度快、控制效果好的特点。     

广义逆在解线性代数方程组中的应用

介绍了广义逆的基本概念，并讨论了广义逆在解线性代数方程组及线性最小二乘问题上的应用。     

矩阵α-β广义逆的加速计算

研究矩阵A∈Cm×n的α-β广义逆的加速计算并且给出了误差界。最后还给出了数值算例。     

关于环上矩阵的Γαβ-广义逆

研究环上矩阵的Гαβ-广义逆和Гαβ-Moore-Penrose逆,得到带有对合反自同构的有单位元的结合环R上的一类可分解矩阵的Гαβ-广义逆和Гαβ-Moore-Penrose逆存在的充要条件及表达式,推广了以往的相应结果。     

算子广义逆发展理论

从矩阵广义逆的发展开始,详细地论述了算子广义逆的发展过程,特别强调了Banach空间中的一些重要结论。     

非交换复微分调控方程边值周期解存在特征分析

非交换复微分调控方程是构建非线性动力系统的基础,对非交换复微分调控方程边值周期解存在特征分析,在高阶累积量矩阵的特征分解和系统设计中具有重要应用价值。构建非交换复微分调控方程的渐进控制闭环系统,估计非交换复微分调控方程的M-P广义逆矩,根据不同场合的需求,进行双边界条件下的平衡点分解,实现边值周期解的存在性分析。用近似线性方法判断其边界平衡点,定义其联合特征函数集合,求解非交换复微分调控方程的两组规范化的第二联合特征函数,得到边值周期解的插值拟合式,证明了交换复微分调控方程的边值周期解具有收敛性。     

二阶系统数值解耦方法的研究

数值代数领域通过保持Lancaster结构来研究二阶系统的解耦问题,但寻找解耦变换涉及到了非线性方程组求解问题,难以实现. 提出了一种二阶系统数值解耦的新方法. 根据系统解耦前后的同谱信息确定解耦后的系统,将寻找解耦变换的非线性问题转化为齐次Sylvester方程求解问题; 并利用矩阵的Kronecker积理论求解二阶系统的解耦变换. 数值试验证明了该方法的可行性,为二阶系统的数值解耦找到了更便易的实现途径.     

有限元矩阵的存贮与分解的实现

在有限元方法中,无论是线形问题还是非线性问题,利用有限元方法离散化后,在大多数情况下,最后都要求解大型对称、正定、带状线形代数方程组。所以,求解这类方程组的各种有效方法,是有限元方法的基本手段之一。本文利用最基本的对称、正定、带状矩阵来研究有限元矩阵的一维存贮问题,并且对有限元矩阵进行三角分解(LLT分解)。     

逆矩阵的性质及在考研中的应用

逆矩阵及其性质是线性代数中的重要的基础知识,在考研试题中占有重要地位。首先总结了逆矩阵的定义及其性质。其次,介绍了求逆矩阵的求解方法,为后面研究考研真题打下基础。最后,从考研真题出发,分析逆矩阵及其性质在考研真题中的运用。找到试题与知识点之间的联系,熟练掌握解题方法,提高解题速度。     

对称扰动理论在偏微分方程中的应用研究

非线性科学已经被广泛应用于数学、物理、化学、经济等领域。许多非线性现象都可以用非线性偏微分方程来很好地描述,所以得到非线性偏微分方程的解具有重要的意义。在研究非线性科学的同时,出现了一些带有扰动项的非线性偏微分方程。为了研究这种扰动偏微分方程,一些以对称理论为基础的扰动方法相继产生。本文主要研究对称扰动理论在偏微分方程中的应用,寻求偏微分方程的近似对称约化和无穷级数解。     

Approximate solution (with error bounds) to a nonlinear,nonautonomous second-order differential equation

Two approximations are developed to the solution of an important nonlinear, nonautonomous second-order differential equation that arises in various fields of science and technology such as operations research, mathematical ecology and epidemiology. The origin of the second-order differential equation from a system of two nonlinear first-order differential equations modelling, for example, Lanchester-type combat between two homogeneous military forces is discussed. Extension of our results to a more general system of nonlinear first-order differential equations is indicated. Error bounds that do not require that the exact solution be known are developed. Some connections between our results and those for the Liouville-Green (or WKB) approximation to the solution of the linear second-order equation are indicated.     

Direct transformation of variational problems into Cauchy systems—II. scalar-semi-quadratic case

This series of papers addresses three interrelated problems: the solution of a variational problem, the solution of integral equations, and the solution of an initial valued system of integrodifferential equations. It will be shown that a large class of variational problems requires the solution of a nonlinear integral equation. It has also been shown that the solution of a nonlinear integral equation is identical to the solution of a Cauchy system. In this paper, we by-pass the nonlinear integral equations and show that the minimization problems directly imply a solution of the Cauchy system. This second paper in the series looks at semi-quadratic functional and scalar functions.     

Chebyshev polynomial solution of nonlinear integral equations

In the current work, the Chebyshev collocation method is adopted to find an approximate solution for nonlinear integral equations. Properties of the Chebyshev polynomials and operational matrix are used in the integral equation of a system consisting of nonlinear algebraic equations with the unknown Chebyshev coefficients. Numerical examples are presented to illustrate the method and results are discussed.     

On numerical solutions for hyperbolic–parabolic equations with the multipoint nonlocal boundary condition

A numerical method is proposed for solving multi-dimensional hyperbolic–parabolic differential equations with the nonlocal boundary condition in t and Dirichlet and Neumann conditions in space variables. The first and second order of accuracy difference schemes are presented. The stability estimates for the solution and its first and second orders difference derivatives are established. A procedure of modified Gauss elimination method is used for solving these difference schemes in the case of a one-dimensional hyperbolic–parabolic differential equations with variable coefficients in x and two-dimensional hyperbolic–parabolic equation.     

A new direct method based on the Chebyshev cardinal functions for variable-order fractional optimal control problems

In this paper, a new direct method based on the Chebyshev cardinal functions is proposed to solve a class of variable-order fractional optimal control problems (V-OFOCPs). To this end, a new operational matrix (OM) of variable-order (V-O) fractional derivative in the Caputo sense is derived for these basis functions and is used to obtain an approximate solution for the problem under study. In the proposed method, the state and the control variables are expanded in terms of the Chebyshev cardinal functions with unknown coefficients, at first. Then, the OM of V-O fractional derivative and some properties of the Chebyshev cardinal functions are employed to achieve a nonlinear algebraic equation corresponding to the performance index and a nonlinear system of algebraic equations corresponding to the dynamical system in terms of the unknown coefficients. Finally, the method of constrained extremum is applied, which consists of adjoining the constraint equations derived from the given dynamical system and the initial conditions to the performance index by a set of undetermined Lagrange multipliers. As a result, the necessary conditions of optimality are derived as a system of algebraic equations in the unknown coefficients of the state variable, control variable, and Lagrange multipliers. Furthermore, some numerical examples of different types are demonstrated with their approximate solutions for confirming the high accuracy and applicability of the proposed method.     

On stability of a class of discrete systems

The problem of stability properties for the solutions of nonlinear difference equations is considered. The approach used is to study the behavior of the solutions of nonlinear difference equations with respect to solutions of a nonlinear difference equation. This is a more general setting than the comparison principle in which the comparison equation is a linear difference equation.The principal technique employed is an extension of Liapunov's direct method. A series of theorems is obtained yielding criteria for the behavior of solutions in terms of existence of the Liapunov-type function with appropriate properties.     

On the matching equations of kinetic energy shaping in IDA-PBC

Interconnection and damping assignment passivity-based control scheme has been used to stabilize many physical systems such as underactuated mechanical systems through total energy shaping. In this method, some partial differential equations (PDEs) related to kinetic and potential energy shaping shall be solved analytically. Finding a suitable desired inertia matrix as the solution of nonlinear PDEs relevant to kinetic energy shaping is a challenging problem. In this paper, a systematic approach to solving this matching equation for systems with one degree of underactuation is proposed. A special structure for desired inertia matrix is proposed to simplify the solution of the corresponding PDE. It is shown that the proposed method is more general than that of some reported methods in the literature. In order to derive a suitable desired inertia matrix, a necessary condition is also derived. The proposed method is applied to three examples, including pendubot, VTOL aircraft, and 2D SpiderCrane.     

A method for the closed-form evaluation of critical buckling loads for planar strongly curved bars

The calculation of critical buckling loads of planar curved bars, subjected to a general co-planar continuous external load (or a general co-planar terminal loading), leads to the solution of transcendental (nonlinear) equations. In this investigation a new method for the closed-form solution of such types of equations is presented. In particular, the transcendental equation u tan γ cot uγ = 1, corresponding to the buckling problem of a cantilever circular bar of high curvature loaded by two co-planar forces acting along its chord, is solved in a closed-form. Finally, several numerical results are presented, based on the Gauss integration rule.