具有衰退记忆的非自治非经典扩散方程的强吸引子

在强拓扑空间$H_0^1(Omega)capH^2(Omega)$$times L_mu^2(mathbb R^+; H_0^1(Omega)capH^2(Omega))$中, 讨论了具有衰退记忆的非自治非经典扩散方程当非线性项临界增长时的长时间动力学行为. 当与时间相关的外力项仅满足平移有界而非平移紧时, 首先得到了强解的渐近正则性, 然后获得了强吸引子的存在性及其结构与正则性.该结果推广和改进了一些已有结果.     

带衰退记忆的经典反应扩散方程的强全局吸引子

当任意阶多项式增长的非线性项为耗散,且外力项仅属于L~2(Ω)时,研究了带衰退记忆的经典反应扩散方程的解在强拓扑空间H_0~1(Ω)×L_μ~2(R~+;D(A))的长时间行为.应用抽象函数理论、半群理论以及新的估计技巧,在拓扑空间H_0~1(Ω)×L_μ~2(R~+;D(A))上,验证了强解半群的渐近紧性并且证明了强全局吸引子的存在性.     

连续映射的渐近行为

本文采用“追溯”法，获得连续映射ｆ的非渐近周期点集为零测集的一个充分条件。     

混合中立型方程渐近衰退正解的存在性

该文利用Krasnoselskii不动点定理,讨论了一阶混合中立型微分方程[x(t)-cx(t-h)-c^*x(t+h^*)]'=p(t)x(g(t)),获得了方程在p\leq p(t)<0与0相似文献   

带衰退记忆的经典反应扩散方程的全局吸引子

当非线性项满足任意阶多项式增长且外力项仅属于H~(-1)(Ω)时,研究了带衰退记忆的经典反应扩散方程的长时间动力学行为.应用抽象函数理论、半群理论以及新的估计技巧,在空间L~2(Ω)×L_μ~2(R~+;H_0~1(Ω))上证明了全局吸引子的存在性.该结果改进和推广了Chepyzhov等人(2006)及Zhong等人(2006)的相应结果.     

函数不连续的二阶拟线性奇摄动边值问题

讨论了函数不连续情况下二阶拟线性奇摄动边值问题,用边界层函数法和轨道的光滑缝接,构造了问题的形式渐近解,并在整个区间上证明了形式渐近解的一致有效性,把吉洪诺夫系统中的函数光滑条件推广到了不连续情况.     

具有不连续系数的奇异摄动拟线性边值问题

研究一类具有不连续系数的奇异摄动二阶拟线性边值问题,其解因一阶导数的不连续性而出现内部层.用合成展开法和上下解定理得到所提问题内部层解的存在性和渐近估计.所得结果应用到由Farrell等（Farrell P A,O＇Riordan E,Shishkin G.A class of singularly perturbed quasilineax differential equations with interiors layers.Mathematics of Computation,2009,78：103-127）所提出的一个特殊拟线性问题.     

具有连续时滞的非自治扩散Lotka—Volterra模型的周期解

本文研究了一类具有周期系数和连续时滞的两种群非自治扩散模型,确定了保证存在一个全局渐近隐定的正周期解的充分条件．     

线性时变切换系统的渐近稳定性研究

考虑一类线性时变切换系统的渐近稳定性.基于矩阵测试理论,文中给出线性时变切换系统在周期切换和等时切换下渐近稳定的充分条件,并通过仿真实例说明结论是正确的.     

关于置换环上强可分性的注记

环R是强可分的,如果对任意有限生成投射R-模A,B,A⊕A ≌B⊕B,则A≌B.该文证明了置换环上的强可分性在亚直积下是不变量.作为应用,证明了R/(IJ)是强可分的当且仅当R/(I∩J)是强可分的.     

具有衰减记忆的多维映射的逼近和系统识别(英)

本文主要研究具有衰减记忆的多维映射的逼近，考虑了因果和非因果两种情形．在实际应用上，可以用来识别一类因果和非因果系统．     

带有衰退记忆的非自治经典反应扩散方程的吸引子

当非线性项以任意阶多项式增长,且外力项仅为平移有界而非平移紧时,研究了非自治经典反应扩散方程解的长时间动力学行为.应用抽象函数理论和新的估计技术,在拓扑空间L~2(Ω)×L_μ~2(R~+;H_0~1(Ω)上,证明了一致吸引子的存在性.该结果改进和推广了Chepyzhov等(2006)和钟承奎等(2006)的相应结果.     

Sequential Identification of Linear Dynamic Systems with Memory

This paper presents a sequential estimator for some unknown parameters in stochastic linear systems with memory. As examples stochastic differential equations with time delayed drift are considered. Based on the maximum likelihood method, we construct an estimation procedure with given accuracy in the sense of the L _p -norm (p 2). It is shown, that this procedure works also in certain cases, when the normalized information matrix of the observed process is asymptotically degenerated. The almost surely consistency of the proposed estimators and the asymptotic behavior of the length of observations are derived.     

一类全局收敛的记忆梯度法及其线性收敛性

本文研究一类新的解无约束最优化问题的记忆梯度法,在强Wolfe线性搜索下证明了其全局收敛性．当目标函数为一致凸函数时,对其线性收敛速率进行了分析．数值试验表明算法是很有效的．     

Asymptotic Decay for Some Differential Systems with Fading Memory

We study the large time behavior of the solution u to an initial and boundary value problem related to the following integro-differential equation $$ u_{tt} = G_0 \Delta u + \int_0^t G'(t-s) \Delta u(x, s)\, ds - a u_t \eqno(0.1) $$ where G 0 , a are real constant coefficients, G 0 > 0, a S 0 and $ G\,' \in L^1({{\shadR}}^ + ) \cap L^2({{\shadR}}^ + ), G\,' \le 0 $ . It is known that, when G ' L 0 and a > 0, the solution u of (0.1) exponentially decays. Here we prove that, for any nonnegative a and for any $ G ' \not \equiv 0 $ , the solution u of the Eq. (0.1) exponentially decays only if the relaxation kernel G ' does. In other words, the introduction of the dissipative term related to G ' does not allow the exponential decay due to the presence of the positive coefficient a . We also prove analogous results for the polynomial decay.     

ON THE ALMOST PERIODIC SOLUTIONS OF HIGHER DIMENSIONAL NONAUTONOMOUS SYSTEMS

By means of the properties of almost periodic system and Lyapunov function, we give some criteria which guarantee the existence and uniqueness and stability of almost periodic solutions of higher dimensional nonautonomous system. The result is more convenient and effective than the related result in[1].     

Random Attractor for the Nonclassical Diffusion Equation with Fading Memory

In this paper,we consider the stochastic nonclassical diffusion equationwith fading memory on a bounded domain. By decomposition of the solution operator, we give the necessary condition of asymptotic smoothness of the solution to the initial boundary value problem, and then we prove the existence of a random attractor in the space $M_1=D(A^{\frac{1}{2}}) × L^2_μ(R^+, D(A^{\frac{1}{2}}))$, where A=-Δ with Dirichlet boundary condition.     

极大代数上多输入多输出线性系统的最小实现

研究了极大代数上无穷阵序列{Gi}0∞的实现问题.首先给出了周期阵序列的概念,得到了1-阶和2-阶周期阵序列{Gi}0∞元素之间的关系,并得到多输入多输出情况下线性系统存在1维和2维最小实现的充要条件.