A REVERSE ORDER IMPLICIT Q-THEOREM AND THE ARNOLDI PROCESS

Let A be a real square matrix and VTAV = G be an upper Hessenberg matrix with positive subdiagonal entries, where V is an orthogonal matrix. Then the implicit Q-theorem states that once the first column of V is given then V and G are uniquely determined. In this paper, three results are established. First, it holds a reverse order implicit Q-theorem: once the last column of V is given, then V and G are uniquely determined too. Second, it is proved that for a Krylov subspace two formulations of the Arnoldi process are equivalent and in one to one correspondence. Finally, by the equivalence relation and the reverse order implicit Q-theorem, it is proved that for the Krylov subspace, if the last vector of vector sequence generated by the Arnoldi process is given, then the vector sequence and resulting Hessenberg matrix are uniquely determined.     

ON THE BEST APPROXIMATION MATRIX PROBLEM AND MATRIX FOURIER SERIES

In this paper the concept of positive definite bilinear matrix moment functional. acting on the space of all the matrix valued continuous functions defined on a bounded interval [a,b], is introduced. The best approximation matrix problem with respect to such a functional is solved in terms of matrix Fourier series. Basic properties of matrix Fourier series such as the Kiemann -Lebesgue matrix property and the bessel-parseval matrix inequality are proved. The concept of total set vjith respect to a positive definite matrix functional is introduced , and the totallity of an orthonormal sequence of matrix polynomials with respect to the functional, is established.     

ON HERMITE MATRIX POLYNOMIALS AND HERMITE MATRIX FUNCTIONS

In this paper properties of Hermite matrix polynomials and Hermite matrix functions are studied. The concept ot total set with respect to a matrix functional is introduced and the total property of the Hermite matrix polynomials is proved. Asymptotic behaviour of Hermite matrix polynomials is studied and the relationship of Hermite matrix functions with certain matrix differential equations is developed. A new expression of the matrix exponential for a wide class of matrices in terms of Hermite matrix polynomials is proposed.     

On Bounds for Spectra of Operator Pencils in a Hilbert Space

A class of pencils(operator-valued functions of a complex argument) in a separeble Hilbert space is considered.Bounds for the spectra are derived.Applications to differential operators,integral operators with delay and in finite matrix pencils are discussed.     

Maximization of the sum of the trace ratio on the Stiefel manifold,I: Theory

We are concerned with the maximization of tr(VTAV)/tr(VT BV)+ tr(VT CV)over the Stiefel manifold {V ∈ Rm×| V T V = It}(t m), where B is a given symmetric and positive definite matrix, A and C are symmetric matrices, and tr() is the trace of a square matrix. This is a subspace version of the maximization problem studied in Zhang(2013), which arises from real-world applications in, for example,the downlink of a multi-user MIMO system and the sparse Fisher discriminant analysis in pattern recognition.We establish necessary conditions for both the local and global maximizers and connect the problem with a nonlinear extreme eigenvalue problem. The necessary condition for the global maximizers offers deep insights into the problem, on the one hand, and, on the other hand, naturally leads to a self-consistent-field(SCF)iteration to be presented and analyzed in detail in Part II of this paper.     

一类解析函数的联合留数插值

The necessary and sufficient conditions are given for the simultaneous two-sided residue interpolation problem with nodes in the open upper half-plane for the matrix-valued analytic functions. A linear fractional transformation of the set of all solutions to the question is presented in terms of the original data. The method is based on characterizing least common minimal multiples and the reduction of the solution of the problem to the construction of a rational matrix function which serves as the coefficient, matrix in the linear fractional transformation.     

Continuity in weak topology:higher order linear systems of ODE

We will introduce a type of Fredholm operators which are shown to have a certain con- tinuity in weak topologies.From this,we will prove that the fundamental matrix solutions of k-th, k≥2,order linear systems of ordinary differential equations are continuous in coefficient matrixes with weak topologies.Consequently,Floquet multipliers and Lyapunov exponents for periodic systems are continuous in weak topologies.Moreover,for the scalar Hill's equations,Sturm-Liouville eigenvalues, periodic and anti-periodic eigenvalues,and rotation numbers are all continuous in potentials with weak topologies.These results will lead to many interesting variational problems.     

Truncated Estimator of Asymptotic Covariance Matrix in Partially Linear Models with Heteroscedastic Errors

A partially linear regression model with heteroscedastic and/or serially correlated errors is studied here. It is well known that in order to apply the semiparametric least squares estimation （SLSE） to make statistical inference a consistent estimator of the asymptotic covariance matrix is needed. The traditional residual-based estimator of the asymptotic covariance matrix is not consistent when the errors are heteroscedastic and/or serially correlated. In this paper we propose a new estimator by truncating, which is an extension of the procedure in White. This estimator is shown to be consistent when the truncating parameter converges to infinity with some rate.     

离散神经网络指数稳定的增强李亚普诺夫方法

This paper addresses the problem of robust stability for a class of discrete-time neural networks with time-varying delay and parameter uncertainties.By constructing a new augmented Lyapunov-Krasovskii function,some new improved stability criteria are obtained in forms of linear matrix inequality（LMI） technique.Compared with some recent results in the literature,the conservatism of these new criteria is reduced notably.Two numerical examples are provided to demonstrate the less conservatism and effectiveness of the proposed results.     

Multivariate refinement equation with nonnegative masks

This paper is concerned with multivariate refinement equations of the type where (?) is the unknown function defined on the s-dimensional Euclidean space Rs, a is a finitely supported nonnegative sequence on Zs, and M is an s×s dilation matrix with m := |detM|. We characterize the existence of L2-solution of refinement equation in terms of spectral radius of a certain finite matrix or transition operator associated with refinement mask a and dilation matrix M. For s = 1 and M = 2, the sufficient and necessary conditions are obtained to characterize the existence of continuous solution of this refinement equation.     

Providing operational analysis to a peace support operation: the Kosovo experience

The Operational Analysis (OA) Branch of the HQ ARRC deployed into Kosovo concurrently with the withdrawal of Serbian forces. The authors, all members of the Operational Analysis Branch, were responsible for providing general scientific, and more specifically Operational Research, advice to General Jackson, Commander of the Kosovo Force. This paper outlines the work done by OA Branch leading up to, and during the challenging period from the first deployment of troops into Kosovo in June 1999 to October 1999. The work of the branch was in two major sections; the first, support to returning Kosovo to normality and the second, to monitor the compliance of the Kosovo Liberation Army (UCK) with the undertaking to demilitarise. OA Branch provided not only the military with work to quantify the return to normality, but also worked with and provided data to aid agencies. The work ranged from assessments of damage to the infrastructure of Kosovo, particularly the housing, through to the monitoring of crime. The population estimates produced by the branch corrected the emotive image being produced in the media, and became the subject of an international press conference. OA Branch's weekly Compliance Monitoring report was the authoritative document for checking on the progress of the UCK towards demilitarisation; this coupled with work on trends in violence were regularly briefed to the KFOR Commander.     

Non-recursive Haar Connection Coefficients Based Approach for Linear Optimal Control

In the present paper, two-fold contributions are made. First, non-recursive formulations of various Haar operational matrices, such as Haar connection coefficients matrix, backward integral matrix, and product matrix are developed. These non-recursive formulations result in computationally efficient algorithms, with respect to execution time and stack-and-memory overflows in computer implementations, as compared to corresponding recursive formulations. This is demonstrated with the help of MATLAB PROFILER. Later, a unified method is proposed, based on these non-recursive connection coefficients, for solving linear optimal control problems of all types, irrespective of order and nature of the system. This means that the single method is capable of optimizing both time-invariant and time-varying linear systems of any order efficiently; it has not been reported in the literature so far. The proposed method is applied to solve finite horizon LQR problems with final state control. Computational efficiency of the proposed method is established with the help of comparison on computation-time at different resolutions by taking several illustrative examples.     

Comparisons between the mathematical models used for the analyses of linear circuits and trusses

The methods for the anlaysis of simple electrical circuits and of structural trusses can be based on matrix formulations. These are derived from the graph theoretical structure of the inter‐connectivity of the components involved and results about the inter‐relationships of the associated physical parameters. This paper looks at the analogies between the two situations and shows that with a good choice of notation the matrix formulations are identical. These ideas can be used in a teaching environment to illustrate that widely different engineering applications are susceptible of similar means of analysis and produce analogous mathematical models.     

有限元体系的M—P逆结构拓扑变化法

本文应用Ｍｏｏｒｅ＿Ｐｅｎｒｏｓｅ逆理论，给出了一套当结构拓扑发生变化时结构静力响应的计算公·式其特点是不需建立求解线性方程组     

Investigation of stress-velocity LSFEMs for the incompressible Navier-Stokes equations

In this contribution three mixed least-squares finite element methods (LSFEMs) for the incompressible Navier-Stokes equations are investigated with respect to accuracy and efficiency. The well-known stress-velocity-pressure formulation is the basis for two further div-grad least-squares formulations in terms of stresses and velocities (SV). Advantage of the SV formulations is a system with a smaller matrix size due to a reduction of the degrees of freedom. The least-squares finite element formulations, which are investigated in this contribution, base on the incompressible stationary Navier-Stokes equations. The first formulation under consideration is the stress-velocity-pressure formulation according to [1]. Secondly, an extended stress-velocity formulation with an additional residual is derived based on the findings in [1] and [5]. The third formulation is a pressure reduced stress-velocity formulation based on a condensation scheme. Therefore, the pressure is interpolated discontinuously, and eliminated on the discrete level without the need for any matrix inverting. The modified lid-driven cavity boundary value problem, is investigated for the Reynolds number Re = 1000 for all three formulations. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

The Gramian expression of a Vandermonde matrix on symmetric points

A new expression for the Gramian of a row-wise Vandermonde matrix is devised, when the values defining the matrix are real and symmetric. The extension to complex values, symmetric with respect to the origin of the complex plane, is also derived. Both these formulations may be useful in symbolic or parallel computation.     

Numerical stability of the BEM for advection‐diffusion problems

A boundary element method (BEM) approach has been developed to solve the time‐dependent 1D advection‐diffusion equation. The 1D solution is part of a 3D numerical scheme for solving advection‐diffusion (AD) problems in fractured porous media. The full 3D scheme includes a 3D solution for the porous matrix, which is coupled with a 2D solution for fractures and a 1D solution for fracture intersections. As the hydraulic conductivity of the fracture intersections is usually higher than the hydraulic conductivity of the fractures and by at least one order of magnitude higher than the hydraulic conductivity of the porous matrix, the fastest flow and solute transport occurs in the fracture intersections. Therefore it is important to have an accurate and stable 1D solution of the transient AD problems. This article presents two different 1D BEM formulations for solution of the AD problems. The particular advantage of these formulations is that they provide one of the most straightforward and simplest ways to couple multiple intersecting 2D Boundary Element problems discretized with linear discontinuous elements. Both formulations are tested and compared for accuracy, stability, and consistency. The analysis helps to select the more suitable formulations according to the properties of the problem under consideration. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004     

A comparison of nonlinear beam finite element formulations

Two alternative nonlinear finite element formulations emanating from the Simo-Reissner beam theory are considered. The orientation of the beam cross section is characterised by a director frame which can be either represented by means of rotational parameters or the direction cosine matrix. In the planar case the use of a single angle can be considered as the canonical formulation. The corresponding finite element approximation relies on the interpolation of the nodal angles. However, the extension of this approach to the three-dimensional case is nontrivial and often leads to element formulations beeing not frame-indifferent. On the other hand, the interpolation of the nodal direction cosines in general yields frame-indifferent element formulations [1, 2]. The present talk focuses on a comparison of the two aforementioned finite element beam formulations for planar problems. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

矩阵型灰色关联度的特征检验方法及其应用

针对现有灰色关联理论的不足, 本文提出灰色关联的特征检验思路, 构建了矩阵型灰色关联度的特征检验方法。首先优化矩阵型灰色关联模型, 利用行为矩阵差值定义特征差异矩阵, 采用矩阵2范数构建关联度公式。而后分析特征差异矩阵的稳定性与趋势性, 利用变异系数形式构建稳定性系数, 利用最小二乘法估计趋势性系数, 两者共同组成矩阵型灰色关联度的特征检验方法。最后, 本文模型被应用于湖北省恩施州的长期多维贫困分析, 在与现有模型的比较中, 发现关联度评估结果有效区分了恩施州8个市县的贫困情况, 特征检验方法从贫困不确定性和趋势性两方面对结果进行补充, 验证了模型的可行性与实用性。