一类具有非线性脉冲接种的SIRS流行病模型分析（英文）

本文建立了一类具有非线性脉冲免疫接种与饱和接触率的SIRS传染病模型;利用离散动力系统的频闪映射方法得到了模型的无病周期解;利用Floquet乘子理论和脉冲微分方程比较定理证明了该周期解的全局渐近稳定性,并获得了模型持久性的充分条件;还通过数值模拟展示了数值模拟结果和理论结果的一致性.     

关于具有脉冲与HollingⅣ型功能反应的时滞捕食-食饵Gompertz模型的研究 [英文]

本文运用比较定理和频闪映射,研究一类具有HollingⅣ型功能反应函数和不同时刻有脉冲收获与储存的Gompertz模型,得到成熟捕食者灭绝周期解存在和全局吸引的充分条件. 利用时滞脉冲微分方程比较理论,研究系统的持久性条件. 最后通过数值模拟进一步验证理论结果的合理性.     

关于具有脉冲与HollingⅣ型功能反应的时滞捕食-食饵Gompertz模型的研究(英文)

本文运用比较定理和频闪映射,研究一类具有HollingⅣ型功能反应函数和不同时刻有脉冲收获与储存的Gompertz模型,得到成熟捕食者灭绝周期解存在和全局吸引的充分条件.利用时滞脉冲微分方程比较理论,研究系统的持久性条件.最后通过数值模拟进一步验证理论结果的合理性.     

一类具有非线性脉冲的捕食与被捕食系统的定性分析

实际的害虫控制策略由于受到资源有限、种群密度的影响,具有饱和效应或非线性特征.因此,该文对一类具有非线性脉冲控制策略的捕食与被捕食模型进行了全局定性分析.利用脉冲微分方程中的Floquet理论和比较方法,得到模型的天敌根除周期解全局渐近稳定的充分条件,通过分支理论,得到非平凡周期解存在性的条件,数值模拟验证了具有非线性脉冲的模型具有非常复杂的动态行为.     

一类脉冲扩散与时滞的捕食-食饵模型研究

运用脉冲时滞微分方程的比较理论,频闪映射和一些分析方法,讨论了一类捕食者具有脉冲扩散、食饵具有阶段结构的捕食-食饵模型得到了成熟食饵灭绝周期解的全局吸引和系统持久的充分条件,证明了系统的所有解是一致完全有界的.最后通过举例并进行数值模拟说明所得结果的正确性.     

脉冲引入外来染病人口HIV/AIDS模型

研究具脉冲输入感染人口的HIV流行病模型.运用脉冲微分方程方程理论,得到脉冲输入周期T相似文献   

一类含有脉冲免疫和治疗的SIR流行病的分析

在考虑脉冲接种和脉冲治疗的基础上,本文提出了一类新的含有两个脉冲过程和治疗的SIR传染病模型.利用频闪映射和Floquet理论,研究了无病周期解的存在性与稳定性,这意味着疫情最终可能灭绝.此外,研究了该流行病持久流行的条件,获得了决定疫情是否发生的基本再生数.最后,通过数值模拟分析,说明了脉冲接种和脉冲治疗对疾病控制的影响.     

脉冲状态反馈控制Holling-Tanner模型的周期解（英文）

本文研究一类脉冲状态反馈控制Holling-Tanner模型.在连续系统的正平衡点全局渐近稳定的情况下,利用半连续动态系统的几何理论和后继函数的方法,获得脉冲系统阶1周期解存在唯一且轨道稳定的充分条件,并通过数值模拟验证了主要结论.     

水葫芦生态系统状态反馈控制

本文研究一类以Logistic增长为基础的具有群体防御的水葫芦生态系统.首先得到无脉冲作用的系统定性结论.其次对具有状态反馈控制的脉冲系统,利用微分方程几何理论中后续函数法得到系统的阶一周期解存在的充分条件,证明该周期解是轨道渐近稳定的,同时利用数值模拟讨论了系统生态意义.     

具有状态脉冲效应的阶段结构的害虫防治模型动力性分析(英文)

本文对符合实际的具有状态脉冲效应的阶段结构的害虫防治模型进行研究,给出半连续动力系统、半连续动力系统的后继函数等的定义,根据动力系统的基本理论,采用脉冲微分方程几何理论的方法研究模型定义的半连续动力系统各种几何性质,得到系统存在阶1周期解的充分条件,阶1周期解全局轨道渐近稳定性的充分条件.获得的理论结果说明我们可以经过一次脉冲、两次脉冲、多次脉冲就能完全控制害虫使之不超过阖值.最后,我们用数值模拟的方法说明结果的正确性.     

具有非单调发生率的传染病模型的动力学研究

假设恢复者所获得免疫力并不是永久的而是在一段时间后会减弱并丧失,建立了一类具有非单调发生率的传染病动力学方程.利用微分方程的基本理论和数值仿真的方法,将对此模型进行动力学性质的分析,得到无病平衡点稳定性和一致持久性的条件.对于该问题有效的措施,即研究使疾病以非单调发生率传染的情形,建立相应的SEIRS传染病模型,得到其无病平衡点的全局稳定性的与之条件以及系统一致持久的充分条件,并进行系统的数值仿真分析.     

A viral infection model with immune circadian rhythms

A viral infection model with immune circadian rhythms is investigated in this paper. By employing the persistence theory, we establish a threshold between the extinction and the uniform persistence of the disease. These results can be used to explain the oscillation behaviors of virus population, which were observed in chronic HBV or HCV carriers. Further, numerical simulations indicate that the dynamics of the lytic component of cytotoxicity T cells (CTLs) is crucial to the outcome of a viral infection.     

Long term dynamics in a mathematical model of HIV-1 infection with delay in different variants of the basic drug therapy model

Infection with HIV-1, degrading the human immune system and recent advances of drug therapy to arrest HIV-1 infection, has generated considerable research interest in the area. Bonhoeffer et al. (1997) [1], introduced a population model representing long term dynamics of HIV infection in response to available drug therapies. We consider a similar type of approximate model incorporating time delay in the process of infection on the healthy T cells which, in turn, implies inclusion of a similar delay in the process of viral replication. The model is studied both analytically and numerically. We also include a similar delay in the killing rate of infected CD4⁺ T cells by Cytotoxic T-Lymphocyte (CTL) and in the stimulation of CTL and analyse two resulting models numerically.The models with no time delay present have two equilibria: one where there is no infection and a non-trivial equilibrium where the infection can persist. If there is no time delay then the non-trivial equilibrium is locally asymptotically stable. Both our analytical results (for the first model) and our numerical results (for all three models) indicate that introduction of a time delay can destabilize the non-trivial equilibrium. The numerical results indicate that such destabilization occurs at realistic time delays and that there is a threshold time delay beneath which the equilibrium with infection present is locally asymptotically stable and above which this equilibrium is unstable and exhibits oscillatory solutions of increasing amplitude.     

The threshold for a stochastic HIV-1 infection model with Beddington-DeAngelis incidence rate

In this paper, we consider a stochastic HIV-1 infection model with Beddington-DeAngelis incidence rate. Before exploring its long-time behavior we show that there is a global positive solution of this model. Then sufficient conditions for extinction of the disease are established. Moreover, we give sufficient conditions for the existence of a stationary distribution of the model through constructing a suitable stochastic Lyapunov function. The stationary distribution implies that the disease is persistent in the mean. Therefore, a threshold value for the disease to disappear or prevail is obtained. Finally, some numerical examples are illustrated to support our theoretical results.     

Numerical Solution to Hybrid Stochastic Differential Systems

Abstract

In this article numerical methods for solving hybrid stochastic differential systems of Itô-type are developed by piecewise application of numerical methods for SDEs. We prove a convergence result if the corresponding method for SDEs is numerically stable with uniform convergence in the mean square sense. The Euler and Runge–Kutta methods for hybrid stochastic differential equations are specifically described and the order of the error is given for the Euler method. A numerical example is given to illustrate the theory.     

一类具有Beddington-DeAngelis型功能反应函数的HIV病毒动力学系统模型的稳定性

基于Nowak等于1996年提出的一类经典的HIV病毒动力学模型,考虑了一类具有Beddington-DeAngelis功能反映函数的HIV病毒动力学模型,并研究了无病毒平衡点的全局稳定性与感染平衡点的局部稳定性等.     

一类具有饱和感染率与治愈率的HIV病理模型

将治愈率以及饱和感染率引入基本的HIV病理模型,构建一个改进的HIV病理模型.利用微分动力系统的相关理论,证明改进模型中无病平衡点和染病平衡点的全局渐近稳定性,然后执行相关的数值模拟以验证所得结论.研究结果表明:在饱和感染率的条件下,HIV感染进程变缓;同时提高治愈率能有效地控制HIV感染.     

Galerkin alternating-direction method for a kind of second-order quasi-linear hyperbolic problems

A kind of second-order quasi-linear hyperbolic equation is firstly transformed into a first-order system of equations, then the Galerkin alternating-direction procedure for the system is derived. The optimal order estimates in H¹ norm and L² norm of the procedure are obtained respectively by using the theory and techniques of priori estimate of differential equations. The numerical experiment is also given to support the theoretical analysis. Comparing the results of numerical example with the theoretical analysis, they are uniform.     

一类三维拟线性双曲型方程交替方向有限元法

对一类一般的三维拟线性双曲型方程通过转化二阶时间导数得到关于一阶时间导数的耦合方程组,然后进行离散得到交替方向有限元格式,应用微分方程先验估计的理论和技巧得到了最优阶H~1-模和L~2-模误差估计,并给出了数值算例,数值结果和理论分析得到很好的吻合.     

Numerical analysis of a mathematical model for propagation of an electrical pulse in a neuron

This article is devoted to the study of a mathematical model arising in the mathematical modeling of pulse propagation in nerve fibers. A widely accepted model of nerve conduction is based on nonlinear parabolic partial differential equations. When considered as part of a particular initial boundary value problem the equation models the electrical activity in a neuron. A small perturbation parameter ε is introduced to the highest order derivative term. The parameter if decreased, speeds up the fast variables of the model equations whereas it does not affect the slow variables. In order to formally reduce the problem to a discussion of the moment of fronts and backs we take the limit ε → 0. This limit is singular and is therefore the solution tends to a slowly moving solution of the limiting equation. This leads to the boundary layers located in the neighborhoods of the boundary of the domain where the solution has very steep gradient. Most of the classical methods are incapable of providing helpful information about this limiting solution. To this effort a parameter robust numerical method is constructed on a piecewise uniform fitted mesh. The method consists of standard upwind finite difference operator. A rigorous analysis is carried out to obtain priori estimates on the solution of the problem and its derivatives. A parameter uniform error estimate for the numerical scheme so constructed is established in the maximum norm. It is then proven that the numerical method is unconditionally stable and provides a solution that converges to the solution of the differential equation. A set of numerical experiment is carried out in support of the predicted theory, which validates computationally the theoretical results. © 2008 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2008