带有双噪声的随机SI传染病模型的稳定性与分岔

建立一个带有双噪声的随机SI传染病模型,运用随机平均法及非线性动力学理论对模型进行化简．通过Lyapunov指数和奇异边界理论,得到模型的局部随机稳定性和全局随机稳定性的条件．根据不变测度的Lyapunov指数和平稳概率密度,分析模型的随机分岔．结果表明,系统在随机因素作用下变得更敏感、更不稳定.     

随机康托集的概率性质

本文讨论了两类随机康托集。关于一类随机康托集，证明它们相交等价于稳定从属过程；关于另一类随机康托集，该文证明了由它们产生的随机过程的密度函数与稳定从属过程的密度函数有很大的相似性。     

复合随机时滞系统的全局稳定

本文主要是研究了具有时滞随机复合系统的反馈律和全局稳定,及其所需要的充分条件.主要的方法是:引入一个测度函数u,使得关于ξ的随机系统稳定,再通过附加条件,从而达到整个复合系统的稳定.     

随机中立型泛函微分方程的稳定性态

给出了一类中立型随机泛函方程的随机一致稳定性的充分条件,利用了新的分析技巧处理中立型时滞项,得到了中立型随机时滞泛函微分方程渐近稳定性的充分判据.在处理各种渐近估计是有效的.     

具接种的随机SIQR流行病模型中平衡点的稳定性分析

基于对具接种的确定性SIQR流行病模型的研究,我们引进了随机扰动,建立随机SIQR流行病模型.通过构造Lyapunov函数,运用Ito公式,得到了随机系统的无病平衡点和地方病平衡点随机渐近稳定的充分条件.进一步猜想当随机扰动的强度较大时,平衡点的稳定性将会被破坏.最后,利用数值仿真验证了所得结论及猜想的正确性.     

无界延迟随机微分方程一般衰减速度的稳定性（英文）

本文用Lyapunov函数技巧对非线性无界延迟随机微分方程建立整体解的存在唯一性定理.利用半鞅收敛定理,研究零解的一般衰减速度的随机稳定性并给出判定定理.     

随机Volterra积分方程相容解的稳定性

本文考虑了随机Volterra积分方程相容解的稳定性.应用Lyapunov第二方法,并以推广的Ito公式为工具,给出了随机Volterra积分方程相容解的几乎确定指数稳定和矩指数稳定的充分性原则.     

一类随机生态系统的生态稳定性

本文引入了混合拟单调方法，并将其应用到Ito型随机生态系统中，得到了一些新的结果。     

随机泛函微分方程的渐近稳定性

应用多个Liapunov函数讨论了随机泛函微分方程解的渐近行为,建立了确定这种方程解的极限位置的充分条件,并且从这些条件得到了随机泛函微分方程渐近稳定性的有效判据,使实际应用中构造Liapunov函数更为方便．同时也说明了该结果包含了经典的随机泛函微分方程稳定性结果为其特殊情况．最后给出的结果在随机Hopfield神经网络中的应用．     

随机测度的g—致胎紧性

本文导出随机测度ｇ—致胎紧的概念，给出了它的等价定义，然后研究了稳定Ｂａｎａｃｈ空间上随机测度ｇ—致胎紧在卷积运算下的性质     

变系数Euler-Bernoulli梁振动发展系统的存在性

讨论变系数Euler-Bernoulli梁振动系统{uu(x,t) η(t)uxxxx(x,t)=0,0＜x＜1,0≤t≤T u(0,t)=ux(0,t)=0,0≤t≤t -uxxx(1,t) muu(1,t)=-αu1(1,t) βuxxx(1,t),0≤t≤T uxt(1,t) =-γuxx(1,t),0≤t≤t u(x,0)=u1(x),u1(x,0),0≤x≤1证明了该系统产生一个发展系统．     

STABILITY AND EXISTENCE OF PERIODIC SOLUTIONS AND ALMOST PERIODIC SOLUTIONS ON LIENARD SYSTEMS

1MainResultsConsidersystem11~.x f(x)x' g(x)~0(1)wheref(x)islocallyintegrable,g(x)isdifferentiablealldg(0)=0.Theroem1Thezerosolutionofsystem(1)isuniformlyasymptoticallystableifbyequivalenttransf'Ormu=xov=X' F(x).DefineW[t,(uif\v)]j6ug(s)ds Iv',thenwisaposi…     

不动点和一类中立型方程的渐近稳定性

本文用不动点定理研究了一类中立型泛函微分方程[x(t)-P(t)x(t-τ)]′+Q(t)x(t-r(t))=0,t≥t0的零解的渐近稳定性,其中τ∈(0,∞),P,Q∈C([t0,∞),R),r∈C([t0,∞),R+),且当t→∞时t-r(t)→∞.我们讨论了r(t)为常数和不为常数两种情况.所得定理改进和包含了前人已有的结果.     

Maximal inequalities for a continuous semimartingale

Let X =( X t ) t S 0 be a continuous semimartingale given by d X t = f ( t ) w ( X t )d d M ¢ t + f ( t ) σ ( X t )d M t , X 0 =0, where M =( M t , F t ) t S 0 is a continuous local martingale starting at zero with quadratic variation d M ¢ and f ( t ) is a positive, bounded continuous function on [0, X ), and w , σ both are continuous on R and σ ( x )>0 if x p 0. Denote X 𝜏 * =sup 0 h t h 𝜏 | X t | and J t = Z 0 t f ( s ) } ( X s )d d M ¢ s ( t S 0) for a nonnegative continuous function } . If w ( x ) h 0 ( x S 0) and K 1 | x | n σ 2 ( x ) h | w ( x )| h K 2 | x | n σ 2 ( x ) ( x ] R , n >0) with two fixed constants K 2 S K 1 >0, then under suitable conditions for } we show that the maximal inequalities c p , n log 1 n +1 (1+ J 𝜏 ) p h Á X 𝜏 * Á p h C p , n log 1 n +1 (1+ J 𝜏 ) p (0< p < n +1) hold for all stopping times 𝜏 .     

approximation for the solutions of stochastic differential equations. iii. jointly weak convergence

We give sufficient conditions for a family Z, e > 0 of continuous finite variation processes to converge weakly to a diffusion process Z. Then we consider the integral equation dXE(t) = (l)(Xe(t))dZE{t) and the stochastic equation dX{i) = (j)(X{t))dZ{t) and denote by X(t,x,w respectively X{t,x,(jo), the solution starting at x. We prove that PoX~l, e>0 converge weakly to Pol     

Stochastic Partial Differential Equations on Manifolds~II. Nonlinear Filtering

The conditional law of an unobservable component x(t) of a diffusion (x(t),y(t)) given the observations {y(s):s[0,t]} is investigated when x(t) lives on a submanifold of . The existence of the conditional density with respect to a given measure on is shown under fairly general conditions, and the analytical properties of this density are characterized in terms of the Sobolev spaces used in the first part of this series.     

变换中含有孤立稳定点的第二积分换元定理

在不定积分第二积分换元定理的条件中,要求变换x=φ(t)不含有稳定点,即:φ′(t)≠0.当变换x=φ(t)中含有孤立稳定点时,给出了变换中含有孤立稳定点的第二积分换元定理.拓宽了第二积分换元定理的应用范围.     

带有负指数 Kirchhoff 方程稳定解的Liouville型定理

In this paper, we consider the Liouville-type theorem for stable solutions of the following Kirchhoff equation ■,where M(t) = a + bt~θ, a 0, b, θ≥ 0, θ = 0 if and only if b = 0. N ≥ 2, q 0 and the nonnegative function g(x) ∈ L_(loc)~1(R~N). Under suitable conditions on g(x), θ and q, we investigate the nonexistence of positive stable solution for this problem.     

具有N策略和负顾客的反馈抢占型M/G/1重试可修排队模型解的渐近行为

研究具有N策略和负顾客的反馈抢占型M/G/1重试可修排队模型的时间依赖解的渐近行为.当初步服务的失效率函数η(x),主要服务的失效率函数μ(x)和修理时间的失效率函数ψ(x)满足0η≤η(x)≤η∞,0μ≤μ(x)≤μ∞,0ψ≤ψ(x)≤ψ∞并且η(x)是Lipschitz连续函数时,证明模型的时间依赖解指数稳定.     

The “Duck Survival” Problem in Three-Dimensional Singularly Perturbed Systems with Two Slow Variables

We consider the system of ordinary differential equations x = f(x,y), y = g(x,y), where x ², y , 0 < 1, and f,g C. It is assumed that the equation g = 0 determines two different smooth surfaces y = (x) and y = (x) intersecting generically along a curve l. It is further assumed that the trajectories of the corresponding degenerate system lying on the surface y = (x) are ducks, i.e., as time increases, they intersect the curve l generically and pass from the stable part {y =(x),g'_y < 0} of this surface to the unstable part {y =(x),g'_y > 0}. We seek a solution of the so-called duck survival problem, i.e., give an answer to the following question: what trajectories from the one-parameter family of duck trajectories for = 0 are the limits as 0 of some trajectories of the original system.