一类具有时滞的流行病模型分析

讨论了一类带有时滞的SE IS流行病模型,并讨论了阈值、平衡点和稳定性.模型是一个具有确定潜伏期的时滞微分方程模型,在这里我们得到了各类平衡点存在条件的阈值R0;当R0<1时,只有无病平衡点P0,且是全局渐近稳定的;当R0>1时,除无病平衡点外还存在唯一的地方病平衡点Pe,且该平衡点是绝对稳定的.     

一类具有非线性传染率的阶段结构传染病模型

讨论了一类带有非线性传染率的阶段结构传染病模型,得到了各类平衡点存在的阈值条件.借助Hurwitz判据、Lasalle不变集原理和Bendixson法则,找到了疾病消除平衡点,及在无因病死亡时,地方病平衡点全局渐近稳定的充要条件.     

R(O)SSLER系统平衡点集的镇定

研究了R\"ossler系统的镇定问题. 当参数变化时, R\"ossler系统具有两条平衡点曲线, 因此是一个多平衡点系统. 在这些平衡点中, 有的是不稳定, 有的平衡点上会出现Hopf分岐.提出了一种多项式反馈控制律, 保证R\"ossler系统的两平衡点曲线上的平衡点都渐近稳定. 现有的方法只能保证某个参数点附近平衡点渐近稳定.     

一类捕食者存在疾病的捕食系统传染病模型

建立并分析一类捕食者存在疾病的捕食系统传染病模型,模型中不考虑疾病对捕获率的影响.通过极限系统理论、Lyapunov稳定性理论分析和Bendixson判据,给出了各类平衡点存在及其全局稳定的条件,并得到了捕食者绝灭和疾病成为地方病的充分必要条件.     

一类采取隔离措施的非线性传染率传染病模型的全局稳定性

讨论一类采取隔离措施的非线性传染率传染病的数学模型,得到了基本再生数Rθ的表达式,当Rθ<1时,仅存在无病平衡点,是全局渐近稳定的;当Rθ>1时,存在两个平衡点,其中无病平衡点不稳定,地方病平衡点全局渐近稳定.     

一类有迁移的SIS流行病模型

研究一类种群有迁移的流行病模型,得到了这类模型的基本再生数R0,证明了R0＜1无病平衡点是局部渐近稳定的,而当R0＞1时无病平衡点是不稳定的.进一步讨论了疾病持续存在与无病平衡点和地方病平衡点全局稳定的条件.     

具有时滞的生态流行病模型的稳定性和Hopf分支

该文考虑一类食饵染病的时滞捕食被捕食模型. 作者分析了系统的非负不变性, 边界平衡点的性质和全局稳定性. 证明了当时滞τ=τ\-1+τ\-2适当小时, 正平衡点是局部渐近稳定的,随着时滞的增加, 正平衡点由稳定变为不稳定, 系统在正平衡点附近发生Hopf分支.     

具有饱和发生率和免疫响应的病毒感染模型的稳定性分析

提出了具有饱和发生率和免疫响应的病毒感染数学模型,得到了基本再生数R_0的表达式.当R_01时,证明了无病平衡点是全局渐近稳定的;当R_01时,得到了免疫耗竭平衡点和持续带毒平衡点局部渐近稳定的条件.     

捕食者与食饵都染病的捕食-被捕食模型分析

建立并分析了一个捕食者和食饵都染病的捕食-被捕食模型,求得了它的非负平衡点.利用Hurwitz判据,用特征根的方法得到了边界平衡点局部渐近稳定的充分条件.进一步利用LaSalle不变性原理获得了正平衡点全局渐近稳定的充分条件.     

具有染病者输入的离散SIR传染病模型分析

引入相应的概率建立了具有染病者输入的离散SIR传染病模型,确定了决定其动力学性态的阂值.在阈值之下模型仅存在无病平衡点,且无病平衡点是全局渐近稳定的;在阈值之上模型是一致持续的,有唯一的地方病平衡点存在,且地方病平衡点是局部渐近稳定的.     

Asymptotic stability analysis of autonomous systems by applying the method of localization of compact invariant sets

The asymptotic stability and global asymptotic stability of equilibria in autonomous systems of differential equations are analyzed. Conditions for asymptotic stability and global asymptotic stability in terms of compact invariant sets and positively invariant sets are proved. The functional method of localization of compact invariant sets is proposed for verifying the fulfillment of these conditions. Illustrative examples are given.     

Stability of equilibria of discrete-time systems in terms of invariant sets

We suggest a new approach to the verification of the stability (or asymptotic stability) of the equilibria of time-invariant discrete-time systems based on stability and asymptotic stability criteria stated in terms of invariant sets. A set-theoretic method for the verification of the conditions in these criteria is presented.     

Localization of limit sets and stability of systems of the neutral type with nonmonotone Lyapunov functionals

We suggest new approaches to the study of the asymptotic stability of equilibria for equations of the neutral type. Nonmonotone indefinite Lyapunov functionals are used. We investigate the localization of solutions with respect to the level surfaces of a Lyapunov functional and a functional estimating the derivative of the Lyapunov functional along the solutions. By using solution localization tests, we obtain new conditions for the asymptotic stability of equilibria for equations of the neutral type with bounded right-hand side. We present asymptotic stability tests that do not impose any a priori stability condition on the difference operator. A generalization of the Barbashin–Krasovskii theorem for nonmonotone indefinite Lyapunov functionals is proved for autonomous equations.     

一类具有阶段结构的三种群竞争系统

对一类具有阶段结构的三种群竞争系统进行了分析,得到了边界平衡点的全局渐近稳定性条件.     

Stability of a three-dimensional diffusive Lotka–Volterra system of type-K with delays

A three-dimensional diffusive Lotka–Volterra system of type-K with delays is investigated. We give a stability analysis in detail for all equilibria of the system and obtain some threshold conditions for linear instability and linear asymptotic stability of each equilibrium. We develop the analytical method for stability analysis of reaction–diffusion equations with multi-delays.     

A ratio‐dependent predator–prey model with stage structure and optimal harvesting policy

In this paper, a ratio‐dependent predator–prey model with stage structure and harvesting is investigated. Mathematical analyses of the model equations with regard to boundedness of solutions, nature of equilibria, permanence and stability are performed. By constructing appropriate Lyapunov functions, a set of easily verifiable sufficient conditions are obtained for the global asymptotic stability of nonnegative equilibria of the model. The existence possibilities of bioeconomic equilibria have been examined. An optimal harvesting policy is also given by using Pontryagin's maximal principle. Copyright © 2007 John Wiley & Sons, Ltd.     

Global Qualitative Analysis for a Ratio-Dependent Predator-Prey Model with Delay

A ratio-dependent predator-prey model with time lag for predator is proposed and analyzed. Mathematical analyses of the model equations with regard to boundedness of solutions, nature of equilibria, permanence, and stability are analyzed. We note that for a ratio-dependent system local asymptotic stability of the positive steady state does not even guarantee the so-called persistence of the system and, therefore, does not imply global asymptotic stability. It is found that an orbitally asymptotically stable periodic orbit exists in that model. Some sufficient conditions which guarantee the global stability of positive equilibrium are given.     

一类具有标准发生率的SIS传染病模型的全局稳定性

研究一类具有标准发生率的SIS传染病模型.应用微分方程定性理论,分别给出了保证该系统地方病平衡点、无病平衡点和总人口消亡平衡点全局渐近稳定的充分条件.     

Global asymptotic stability analysis by the localization method of invariant compact sets

We study the asymptotic stability and the global asymptotic stability of equilibria of autonomous systems of differential equations. We prove necessary and sufficient conditions for the global asymptotic stability of an equilibrium in terms of invariant compact sets and positively invariant sets. To verify these conditions, we use some results of the localization method for invariant compact sets of autonomous systems. These results are related to finding sets that contain all invariant compact sets of the system (localizing sets) and to the behavior of trajectories of the system with respect to localizing sets. We consider an example of a system whose equilibrium belongs to the critical case.     

On the asymptotic stability of equilibria of nonlinear mechanical systems with delay

We consider some classes of nonlinear mechanical systems with retarded argument. It is assumed that, in the absence of delay, the systems in question have asymptotically stable equilibria. We analyze how the delay affects the stability of these equilibria. The Lyapunov function method and Razumikhin’s approach are used to derive conditions under which asymptotic stability is preserved for arbitrary delay values. We suggest a method for stabilizing strongly nonlinear conservative systems by constructing a delay feedback control depending only on the generalized coordinates.