广义系统正则状态观测器的存在性和设计

水文借助于广义函数与矩阵广义逆理论,在前人工作的基础上证明了广义系统的(包括干扰解耦的)正则状态观测器的设计问题,等价于一个低于rank E阶的正则系统的相应问题,从理论上解决了广义系统正则状态观测器的设计问题。     

奇异二阶拟线性椭圆型方程Dirichlet问题（Ⅲ）

本文应用摄动方法、上下解方法、截断函数方法，得到了一类带奇异项的二阶拟线性椭圆型方程Ｄｉｒｉｃｈｌｅｔ问题正解的存在性和正则性，发展了文献［１］－［７］的相应工作．     

一类不确定线性脉冲系统的奇异H_∞控制

主要讨论一类不确定线性脉冲系统的奇异H_∞控制问题,当系统不满足正则性条件时,给出奇异H_∞控制问题可解的充分条件,并且控制律保证闭环系统达到内稳定且满足干扰衰减.     

基于严格线性矩阵不等式的奇异系统的H2控制

本文研究了一类线性连续奇异系统的H2控制问题.利用严格线性矩阵不等式的方法,获得了奇异系统H2控制的新的有界实引理,保证了奇异系统的正则性、稳定性、无脉冲性及H2性能.     

奇异系统的正常最小阶状态观测器

本文利用特殊的“快”反馈，在能观的奇异系统的对偶系统中消除脉门冲，获得能控的正常子系统，然后在此降阶的正常子系统的对偶基础上设计状态观测器，本文提出了一般状态能观奇异系统的最小阶正常状态观测器的一种设计途径。     

一类非线性离散系统基于有界反馈的奇异H_∞控制问题

主要研究基于有界控制律的一类非线性离散系统的奇异H∞控制问题.在系统不满足正则条件的情况下,分离出正则部分与非正则部分,给出基于有界反馈与二次Lyapunov函数的离散系统奇异H∞问题可解性的必要条件以及充分条件,求出的有界控制律能使得闭环系统在保证内稳定的条件下达到干扰衰减.     

模的弱消去问题与qu－正则环

本文考虑模的弱消去问题与正则环的Ｓｔａｂｌｅｒａｎｇｅ条件，引进了ｑｕ－正则环的概念，并用它刻划了一类满足弱消去条件的模，刻划了ｑｕ－正则环，指出一切满足比较公理的正则环均为ｑｕ－正则环．文中还考虑这些结果的应用．例如，刻划了满足弱消去律的拟内射模；证明了素的正则右自内射环上的任意非奇异内射右Ｒ－模可以从直和项中弱消去．     

模的弱消去问题与qu－正则环

本文考虑模的弱消去问题与正则环的Ｓｔａｂｌｅｒａｎｇｅ条件，引进了ｑｕ－正则环的概念，并用它刻划了一类满足弱消去条件的模，刻划了ｑｕ－正则环，指出一切满足比较公理的正则环均为ｑｕ－正则环．文中还考虑这些结果的应用．例如，刻划了满足弱消去律的拟内射模；证明了素的正则右自内射环上的任意非奇异内射右Ｒ－模可以从直和项中弱消去．     

基于输入输出线性化方法的一类非线性系统观测器设计

研究一类非线性系统的观测器设计问题.基于输入输出线性化方法提出了一类非线性系统的观测器设计.并且此非线性系统具有多输入多输出的特点,证明了在适当条件下,提出的观测器保证了观测误差渐近趋于零.仿真例表明了所得结果的有效性.     

临界增长的半线性椭圆方程的一个奇异扰动问题

本文考虑下面的奇异扰动问题－Δｕ＝ｕ２－１＋εｕ，ｘ∈Ω；ｕ＞０，ｘ∈Ω；ｕ＝０，ｘ∈Ω，其中Ω是ＲＮ的一个有界区域，Ｎ５，２＝２ＮＮ－２本文证明了当ｘ０是Ｈ（ｘ，ｘ）的一个严格局部极小点时，其中Ｈ（ｘ，ｙ）是Ｇｒｅｅｎ函数的正则部分，则所考虑的问题在ε＞０充分小时，存在解ｕε满足｜Ｄｕε｜２ＳＮ／２δｘ０，这里，Ｓ是Ｓｏｂｏｌｅｖ嵌入Ｈ１（ＲＮ）Ｌ２（ＲＮ）的最佳常数     

Singular optimal controls of stochastic recursive systems and Hamilton–Jacobi–Bellman inequality

In this paper, we study the optimal singular controls for stochastic recursive systems, in which the control has two components: the regular control, and the singular control. Under certain assumptions, we establish the dynamic programming principle for this kind of optimal singular controls problem, and prove that the value function is a unique viscosity solution of the corresponding Hamilton–Jacobi–Bellman inequality, in a given class of bounded and continuous functions. At last, an example is given for illustration.     

Neural firing rate model with a steep firing rate function

In this study we justify rigorously the approximation of the steep firing rate functions with a unit step function in a two-population neural firing rate model with steep firing rate functions. We do this justification by exploiting the theory of switching dynamical systems. It has been demonstrated that switching dynamics offer a possibility of simplifying the dynamical system and getting approximations of the solution of the system for any specific choice of parameters. In this approach the phase space of the system is divided into regular and singular domains, where the limit dynamics can be written down explicitly. The advantages of this method are illustrated by a number of numerical examples for different cases of the singular domains (i.e. for black, white and transparent walls) and for specific choices of the parameters involved. General conditions have been formulated on these parameters to give black, white and transparent walls. Further, the existence and stability of regular and singular stationary points have been investigated. It has been shown that the regular stationary points (i.e. stationary points inside the regular domains) are always stable and this property is preserved for smooth and sufficiently steep activation functions. In the most technical part of the paper we have provided conditions on the existence and stability of singular stationary points (i.e. those belonging to the singular domains). For the existence results, the implicit function theorem has been used, whereas the stability of singular stationary points is addressed by applying singular perturbation analysis and the Tikhonov theorem.     

Permutations of tori in integrable Hamiltonian systems and spectral series of pseudodifferential operators

In the present paper, we study integrable Hamiltonian systems with two degrees of freedom, whose regular level sets consist of several Liouville tori, and the bifurcation diagram has an isolated point. We study assumptions under which going around the singular point causes a permutation of the tori. We also consider a quantum analog of this situation and give model examples.     

求解一类具有Hibert核的奇异积分方程的小波方法

1　引　　言近年来,用小波方法数值求解积分方程越来越引起人们的注意.文献[1]提出的算法可将一类积分算子所对应的矩阵稀疏化,为小波方法快速求解积分方程开辟了一条新的道路这方面的研究不仅可以深入发展小波理论和应用算法,深入发展小波方法的功效,而且对边界元方法有重要的指导意义.然而研究稳健快速的数值方法,一直是这方面研究的难点问题.本文考虑带Hilbert核的奇异积分方程q(y)=12π∫2π0f(x)ctg12(x-y)dx,y∈[0,2π],(1.1)的小波数值解法;其中f(x)∈H2π,q(y)∈H2π是以2π为周期的Holder类函数;q(y)已知,f(x)待求解;(1.1)式右…     

奇异脉冲系统的奇异H_∞控制

主要研究奇异脉冲系统的奇异H∞控制问题.当系统不满足正则条件时,给出奇异脉冲系统的奇异H∞控制问题可解的充分条件,控制律使得闭环系统在保证内稳定的条件下达到干扰衰减.     

退化时滞中立型微分系统解的存在唯一性及指数估计

本文主要讨论退化时滞中立型微分系统解的存在唯一性及指数估计问题.通过定义正则矩阵对讨论退化时滞中立型微分系统解的存在唯一性.再定义基解矩阵以及Laplace变换,给出该系统的通解表达式,最后利用通解表达式和Gronwall-Bellman积分不等式给出该系统解的指数估计及解的精确指数界限.     

广义系统渐近稳定性的一种新的Lyapunov判别方法

本文中，对广义系统构造了一种新的Lyapunov函数，并给出相应的渐近稳定性的Laypunov判别方法。另外，我们证明了当广义系数为R－能稳时，必存在一反馈控制使得闭环系统为渐近稳定性的。     

On regular and singular interval systems

We give a survey on interval linear systems discussing problems for regular systems as well as for singular ones. We consider several solution sets and direct methods to enclose them. Moreover we study iterative methods, particularly the total step method as the basis for other ones. We also use this method for enclosing solutions of singular linear systems.     

Generalized steiner triple systems with group size five

Generalized Steiner triple systems, GS(2, 3, n, g) are used to construct maximum constant weight codes over an alphabet of size g+1 with distance 3 and weight 3 in which each codeword has length n. The existence of GS(2, 3, n, g) has been solved for g=2, 3, 4, 9. In this paper, by introducing a special kind of holey generalized Steiner triple systems (denoted by HGS(2, 3, (n, u), g)), singular indirect product (SIP) construction for GDDs is used to construct generalized Steiner systems. The numerical necessary conditions for the existence of a GS(2, 3, n, g) are shown to be sufficient for g=5.