Stability for several type of interval matrices

The robust stability for some types of tlme-varying interval raatrices and nonlineartime-varying interval matrices is considered and some sufficient conditions for robust stability of such interval matrices are given, The main results of this paper are only related to the verticesset of a interval matrices, and therefore, can be easily applied to test robust stability of interval matrices. Finally, some examples are given to illustrate the results.     

Stability Robustness of LQ Optimal Regulators Based on Multirate Sampling of Plant Output

The stability robustness of stable feedback loops, designed on the basis of multirate-output controllers (MROCs), is analyzed in this paper. For MROC-based feedback loops, designed in order to achieve LQ optimal regulation, we characterize additive and multiplicative norm-bounded perturbations of the loop transfer function matrix which do not destabilize the closed-loop system. New sufficient conditions for stability robustness, in terms of elementary MROC matrices, are presented. Moreover, guaranteed stability margins for MROC-based LQ optimal regulators are suggested for the first time. These margins are obtained on the basis of a fundamental spectral factorization equality, called the modified return difference equality, and are expressed directly in terms of elementary cost and system matrices. Sufficient conditions in order to guarantee the suggested stability margins are established. Finally, the connection between the suggested stability margins and the selection of cost weighting matrices is investigated and useful guidelines for choosing proper weighting matrices are presented.     

Stochastic exponential robust stability of interval neural networks with reaction–diffusion terms and mixed delays

The stochastic exponential robust stability is considered for a class of delayed neural networks with reaction–diffusion terms and Markov jumping parameters in this paper. It is assumed that the uncertain weight matrices belong to the given interval matrices. Some sufficient conditions for the stochastic exponential robust stability of the system are established by applying vector Lyapunov function method and M-matrix theory. The obtained results involving the effect of reaction–diffusion improve the existing conditions. Finally, two examples with numerical simulations are given to illustrate the obtained results.     

Ordering Epic R-fields

We are concerned with the following problem. Given a ring R and an epic R-field K, under what conditions can K be fully ordered? Epic R-fields can be constructed in terms of matrices over R; this makes it natural to consider matrix cones over R rather than ordinary cones of elements of K. Essentially, a matrix cone over R, associated with a given ordering of K, consists of all square matrices which either become singular or have positive Dieudonné determinant over K. We give necessary and sufficient conditions in terms of matrix cones for (i) an epic R-field to be orderable, (ii) a full order on R to be extendable to a field of fractions of R and (iii) for such an extension to be unique.     

Summation of bounded sequences by regular positive matrices

In terms of elements of regular positive discrete and semicontinuous matrices sufficient conditions are obtained that these matrices do not sum a given real,divergent, bounded sequence and, in particular, that the core of a given sequence coincides with the core of the sequence (function) transformed with the aid of a matrix. These conditions permit certain facts, some well-known and some new, on the theory of inefficient matrices to be obtained.Translated from Matematicheskie Zametki, Vol. 12, No. 2, pp. 179–188, February, 1973.     

时滞Cohen—Grossberg神经网络的全局渐近稳定性

本文通过构造一种新的Lyapunov泛函,得到了时滞Cohen—Gmssberg神经网络的全局渐近稳定性的充分条件,这个条件是通过线性矩阵不等式（LIM）的形式表示出来的,条件中的自由权矩阵表明本文的结论具有较小的保守性。     

正互反矩阵一致性的一个充要条件

<正> 层次分析法是一种实用的多维决策方法。在这种分析法中将一个复杂的无结构问题按照属性的不同把它的元素分成若干组,形成互不相交的层次,上一层次的元素对相邻的下一层次     

线性时滞系统的稳定性和镇定问题

本文讨论了线性时滞系统(?)(t)=Ax(t)+Bx(t-r),给出了系统绝对稳定的充分条件,且直接用系数矩阵描述,并讨论了其受控系统(?)(t)=Ax(t)+Bx(t-r)+Cu(t)的镇定问题。     

Some classes of nonsingular matrices and applications

Motivated by conditions that arise from results on mean first passage times matrices in Markov chains, we consider here two classes of real matrices whose elements satisfy some of these conditions, or variation thereof, and which result in the nonsingularity of their elements. The conditions are quite distinct from Ger?gorin circles-type conditions. Our results lead to a sufficient condition for matrices to have 1 as their unique positive eigenvalue.     

The inverses of Toeplitz band matrices

The elements of the inverse of a Toeplitz band matrix are given in terms ofthe solution of a difference equation. The expression for these elements is a quotient of determinants whose orders depend the number of nonzero superdiagonals but not on the order of the matrix. Thus, the formulae are particularly simple for lower triangular and lower Hessenberg Toeplitz matrices. When the number of nonzero superdiagonals is small, sufficient conditions on the solution of the abovementioned difference equation can be given to ensure that the inverse matrix is positive. If the inverse is positive, the row sums can be expressed in terms of the solution of the difference equation.     

有脉冲影响的κ-值逻辑网络的不动点与稳定性

讨论了有脉冲影响的κ-值逻辑网络的不动点及稳定性问题.利用矩阵的半张量积方法,首先将有脉冲影响的κ-值逻辑网络转化成基于矩阵的离散时间动态系统.然后,给出一点是系统不动点的充要条件.最后,给出了两种不同类型控制下系统稳定的充要条件.     

Global exponential stability of impulsive fuzzy cellular neural networks with mixed delays and reaction-diffusion terms

In this paper, the global exponential stability of impulsive fuzzy cellular neural networks with mixed delays and reaction-diffusion terms is considered. By establishing an integro-differential inequality with impulsive initial condition and using the properties of M-cone and eigenspace of the spectral radius of nonnegative matrices, several new sufficient conditions are obtained to ensure the global exponential stability of the equilibrium point for fuzzy cellular neural networks with delays and reaction-diffusion terms. These results extend and improve the earlier publications. Two examples are given to illustrate the efficiency of the obtained results.     

The semigroup generated by a unitary orbit of a singular matrix

We investigate the structure of the multiplicative semigroup generated by the set of matrices that are unitarily equivalent to a given singular matrix A. In particular, we give necessary and sufficient conditions, in terms of the singular values of A, for such a semigroup to consist of all matrices of rank not exceeding the rank of A.     

Strong regularity of parametric interval matrices

Several verifiable sufficient and necessary conditions for strong regularity of parametric interval matrices are given. The conditions are formulated in terms of the spectral radius, positive definiteness and eigenvalues of certain real matrices and a scaled maximum norm.     

对角占优矩阵奇异-非奇异的充分必要判据

本文研究对角占优矩阵奇异-非奇异的充分必要条件.基于Taussky定理,本文得出,可约对角占优矩阵的奇异性由其独立Frobenius块的奇异性决定,从而将这一问题化为不可约对角占优矩阵的奇异-非奇异性问题;运用Taussky定理研究奇异不可约对角占优矩阵的相似性和酉相似性,获得这类矩阵元素辐角间的关系;并与Taussky定理给出的这类矩阵元素模之间的关系结合在一起,研究不可约对角占优矩阵奇异的充分必要条件;最后给出不可约对角占优矩阵奇异-非奇异性的判定方法.     

Ranks of zero patterns and sign patterns

Let F be a field with at least three elements. Zero patterns P such that all matrices over F with pattern P have the same rank are characterized. Similar results are proven for sign patterns. These results are applied to answering two open questions on conditions for formal nonsingularity of a pattern P, as well as to proving a sufficient condition on P such that all matrices over F with pattern P have the same height characteristic.     

非奇异H矩阵迭代式充分条件

非奇异H矩阵是一类应用非常广泛的特殊矩阵.从矩阵元素出发,给出了一组非奇异H矩阵新的简捷而实用的迭代形式的充分条件.该迭代形式的充分条件推广并改进了相关的结果.最后用数值算例验证了该迭代式条件的优越性.     

The semigroup generated by a unitary orbit of a singular matrix

We investigate the structure of the multiplicative semigroup generated by the set of matrices that are unitarily equivalent to a given singular matrix A. In particular, we give necessary and sufficient conditions, in terms of the singular values of A, for such a semigroup to consist of all matrices of rank not exceeding the rank of A.     

Stability with probability 1 of solutions of systems of linear stochastic differential-difference Ito equations

Conditions for absolute (independent of lags) asymptotic stability with probability 1 of systems of stochastic equations cited in the title of this paper are obtained. The proposed approach allows us to reduce the problem of analyzing stability to determination of the conditions for the existence of a positively determined solution of a linear matrix equation. These conditions are stated in terms of locations of eigenvalues of the matrix constructed from the elements of the matrices of the initial system.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 43, No. 2, pp. 147–151, February, 1991.     

Lyapunov Stability of a Class of Operator Integro-differential Equations with Applications to Viscoelasticity

The Lyapunov stability is analysed for a class of integro-differential equations with unbounded operator coefficients. These equations arise in the study of non-conservative stability problems for viscoelastic thin-walled elements of structures. Some sufficient stability conditions are derived by using the direct Lyapunov method. These conditions are formulated for arbitrary kernels of the Volterra integral operator in terms of norms of the operator coefficients. Employing these conditions the supersonic flutter of a viscoelastic panel is studied and explicit expressions for the critical gas velocity are derived. Dependence of the critical flow velocity on the material characteristics and compressive load is analysed numerically.