ED(i)形图簇的伴随多项式的因式分解及色性分析

令Dm表示三阶完全圈K3的一个顶点与路Pm-2的一个1度点重迭后得到的图；ψD^(i)(k,m），表示把Dm的第i个顶点（第1个顶点是1度点）与星图Sk 1的k度点重迭后得到的图；Erm r-1^D(i)表示把rDm中一个分支的第i个顶点与Sr的r-1度点重迭，同时把其余r-1个分支的第i个顶点分别与Sr的r-1个1度点都依次连一条边后得到的图。我们证明了对于1≤i≤m,r≥2，科簇Erm r-1^D(i) ∪(r-1)K1与Dm∪(r-2)ψD^(i)(1,m)∪ψD^(i)(r,m)两的补图是色等价的。     

整环上几类矩阵空间的保持伴随矩阵线性算子

本文刻画了整环上的全矩阵空间、对称矩阵空间和上三角矩阵空间上保持伴随矩阵的线性算子的结构。     

Exact Controllability and Boundary Stabilization of Torsional Vibrations of an Internally Damped Flexible Space Structure

In this paper, we study the exact controllability and boundary stabilization of the torsional vibrations of a flexible space structure (such as a solar cell array) modeled by a rectangular panel, incorporating the material damping of the structure. The panel is hoisted at one end by a rigid hub and the other end is totally free. For the attachment of this hub on one side of the panel, the hub dynamics leads to a nonstandard boundary condition. To incorporate internal damping of the material, we assume Voigt-type viscoelasticity of the structure. Exact controllability theory is established using the Hilbert uniqueness method by means of a control torque applied only on the rigid hub of the panel. At the same time, uniform exponential energy decay rate is obtained directly for the solution of this problem.     

The Semigroup Characterizations of Nil BCI-Algebras

In this paper, some characterizations of nil BCI-algebras X are given by disscusing the adjoint semigroup of X. Moreover, the definition of generalized positive implicative BCI-algebras is introduced and some properties are obtained.AMS Subject Classification (1991): 03G25, 06F35.The subject supported by the Educational Committee of Hebei.     

Control of a hybrid conditionally linear Gaussian process

A control problem is considered where the coefficients of the linear dynamics are functions of a noisily observed Markov chain. The approximation introduced is to consider these coefficients as functions of the filtered estimate of the state of the chain; this gives rise to a finite-dimensional conditional Kalman filter. A minimum principle and a new equation for an adjoint process are obtained.This research was partially supported by NSERC under Grant A-7964, by the US Air Force Office of Scientific Research under Contract AFOSR-86-0332, and by the US Army Research Office under Contract DAAL03-87-0102.The authors obtained these results during a visit to UCSD by the first author in January 1990. This author wishes to thank Professor D. D. Sworder and his department for their hospitality.     

Ergodicity of asymptotically mean stationary channels

Some equivalence conditions for an asymptotically mean stationary channel to be ergodic are given. Incidental results on asymptotically mean stationary measures are also given. Absolute continuity of measures plays a crucial role.     

Sensitivity analysis and model optimization for reaction-diffusion systems

This paper presents a computational framework for the optimization and sensitivity analysis of a process whose state depends upon several parameter functions. Assuming that the process is described by a system of quasilinear, parabolic, partial differential equations, we show how determining the problem parameters so as to improve an associated objective functional is directly related to knowing the state function sensitivities. An expression for the gradient of the objective functional in terms of the solutions of an adjoint system enables one to bypass the calculation of state function sensitivities. These concepts are illustrated for a simple model of cooperative processes in chemical kinetics. Since sensitivity analysis and model optimization are important tools for investigating parameter dependence and validating mathematical models, research developments in such diverse fields as optimal design theory, chemical kinetics, and parameter identification are important motivations for this paper.This author would like to gratefully acknowledge Dr. M. Delle Donne, EGG, for several helpful discussions.This author was partially supported by NSF Grant No. CMS-80-05677.     

On the estimation of mixing coefficients for a multiphase service system

We consider a multiphase service system with a Poisson input flow. Its intensity depends on the number of customers under service. The stationary distribution for this system can be found in an explicit form. We study the rate of convergence to this stationary distribution as well as the bounds for some mixing coefficients. Coupling arguments and Liapunov's function approach form the basis of considerations. This revised version was published online in June 2006 with corrections to the Cover Date.     

Nonhomogeneous markov chains with desired properties - the nearest markovian model

A new class of operators performing an optimization (optimization operators or, simply, optimators) which generate transition matrices with required properties such as ergodicity, recurrence etc., is considered and their fundamental features are described. Some criteria for comparing such operators by taking into account their strenght are given and sufficient conditions for both weak and strong ergodicity are derived. The nearest Markovian model with respect to a given set of observed probability vectors is then defined as a sequence of transition matrices satisfying certain constraints that express our prior knowledge about the system. Finally, sufficient conditions for the existence of such a model are given and the related algorithm is illustrated by an example.