Extinction and permanence of chemostat model with pulsed input in a polluted environment

In this paper, chemostat model with pulsed input in a polluted environment is considered. By using the Floquet theorem, we find the microorganism eradication periodic solution is globally asymptotically stable if some conditions are needed. At the same time we can find the condition of the nutrient and microorganism are permanent.     

A impulsive infective transmission SI model for pest control

In this paper, we propose a model with impulsive control of epidemics for pest management. By using Floquet's theorem, small‐amplitude perturbation skills and comparison theorem, we show that there exists a globally asymptotically stable susceptible pest‐eradication periodic solution when the release amount of infective pests is larger than some critical value. However, when the amount of infective pests released is less than this critical value, the system is shown to be permanent, which implies that the trivial periodic susceptible pest‐eradication solution loses its stability. Further, the existence of a positive periodic endemic solution and other rich dynamics are also studied by numerical simulation. Therefore, we can use the amount of release of infective pests to control susceptible pests at desirable low levels. Copyright © 2007 John Wiley & Sons, Ltd.     

Dynamics of SIS model with saturation incidence,infection age and impulsive birth

In this paper, an impulsive birth and infection age SIS epidemic model is studied. Since infection age is an important factor of epidemic progression, we incorporate the infection age into the model. In this model, we analyze the dynamical behaviors of this model and point out that there exists an infection‐free periodic solution that is globally asymptotically stable if R₀<1. When R₁>1, R₂<1, then the disease is permanent. Our results indicate that a large period T of pulse, or a small pulse birth rate p is the sufficient condition for the eradication of the disease. Copyright © 2009 John Wiley & Sons, Ltd.     

Impulsive control strategy of a pest management SI model with nonlinear incidence rate

In this work, we consider a pest management SI model with impulsive release of infective pests and spraying pesticides. We prove that all solutions of the investigated system are uniformly ultimately bounded and the pest-extinction periodic solution is globally asymptotically stable when some condition is satisfied. We also obtain the permanent condition of the system. It is concluded that the approach of combining impulsive release of infective pests with impulsive spraying pesticides provides reliable tactic basis for the practical pest management.     

Dynamical analysis of a five-dimensioned chemostat model with impulsive diffusion and pulse input environmental toxicant

In this paper, we consider a five-dimensioned chemostat model with impulsive diffusion and pulse input environmental toxicant. Using the discrete dynamical system determined by the stroboscopic map, we obtain a microorganism-extinction periodic solution. Further, it is globally asymptotically stable. The permanent condition of the investigated system is also analyzed by the theory on impulsive differential equation. Our results reveal that the chemostat environmental changes play an important role on the outcome of the chemostat.     

Extinction and permanence of a two-prey two-predator system with impulsive on the predator

In this paper, the dynamic behaviors of a two-prey two-predator system with impulsive effect on the predator of fixed moment are investigated. By applying the Floquet theory of liner periodic impulsive equation, we show that there exists a globally asymptotically stable two-prey eradication periodic solution when the impulsive period is less than some critical value. Further, we prove that the system is permanent if the impulsive period is large than some critical value, and meanwhile the conditions for the extinction of one of the two prey and permanence of the remaining three species are given. Finally, numerical simulation shows that there exists a stable positive periodic solution with a maximum value no larger than a given level. Thus, we can use the stability of the positive periodic solution and its period to control insect pests at acceptably low levels.     

具脉冲扩散的一个三维Chemostat模型动力学分析

研究具脉冲扩散的一个三维Chemostat模型.利用离散动力系统频闪映射,得到了微生物种群灭绝周期解,它是全局吸引的;利用脉冲微分方程理论,得到了系统持久的条件.结论揭示了Chemostat环境变化对Chemostat的产量起着重要的作用.     

一类具有脉冲收获和投放的捕食系统的研究

建立了一类具有Ivlev功能反应函数的捕食系统,引入二次脉冲对该系统中捕食者进行作用,讨论了系统的有界性,利用Floquet理论和小振幅扰动方法,得出了食饵灭绝的周期解的局部稳定性和该系统最终持久生存的条件.     

GLOBAL STABILITY OF SIVS MODEL WITH SATURATION INCIDENCE, INFECTION AGE AND IMPULSIVE VACCINATED RATE

In this paper, an impulsive vaccinated strategy to eradicate SIVS epidemic model is studied. Since infection age is an important factor of epidemic progression, we incorporate the infection age into the model. In this model, we analyze the dynamic behaviors of this model and obtain that there exists an infection-free periodic solution which is globally asymptotically stable under a sufficient condition. Our results indicate that a short period of pulse or a large pulse vaccination rate is the sufficient con...     

证券投资者的进化博弈模型建立及渐进均衡研究

运用进化博弈相关理论,以我国证券市场中的理性和非理性投资者为局中人建立进化博弈单群体模型,并求解此单群体模型的渐进稳定均衡策略,得到理性与非理性投资者的渐进稳定均衡比例,得出理性交易策略与噪声交易策略应同时存在而且适度的噪声有利于保持市场的流动性的结论,为我国证券市场和政府监管者提出政策性建议.     

Some new results for a logistic almost periodic system with infinite delay and discrete delay

A nonautonomous logistic almost periodic system with infinite delay and discrete delay is considered. Our result shows that the system is globally asymptotically stable under the condition for the boundedness of the system. By using almost periodic functional Hull theory and new computational techniques, we show that the almost periodic system has a unique globally asymptotically stable strictly positive almost periodic solution under the condition for the boundedness of the system. Some recent results are improved, and an open question is answered.     

New global stability conditions for a class of difference equations

In this paper we consider some classes of difference equations, including the well-known Clark model, and study the stability of their solutions. In order to do that we introduce a property, namely semicontractivity, and study relations between ‘semi-contractive’ functions and sufficient conditions for the solution of the difference equation to be globally asymptotically stable. Moreover, we establish new sufficient conditions for the solution to be globally asymptotically stable, and we improve the ‘3/2 criteria’ type stability conditions.      

Impulsive control strategy for a chemostat model with nutrient recycling and distributed time‐delay

On the basis of the simplest and deterministic chemostat model, we introduce impulsive input, nutrient recycling, and distributed time‐delay into the model in this paper. By using comparison theorem, Floquet theory, and small amplitude skills in the impulsive differential equation, it proves that if the period of impulsive input is too long and the parameter α of the kernel function in the delay is too small, then there exists a microorganism‐eradication periodic solution that is globally asymptotically stable, and the cultivation of the microorganism fails. On the contrary, if we choose suitable impulsive strategy, such as increasing the concentration of the substrate or enhance the proportion of the concentration of the impulsive input of the substrate at periodic time to that for the microbial growth, then the system could be controlled to be permanent, and the cultivation of the microorganism will be successful. Copyright © 2013 John Wiley & Sons, Ltd.     

Threshold dynamics for an HIV model in periodic environments

In this paper, we investigate an HIV model incorporating the effect of an ARV regimen. Since drug concentration varies during dose intervals, which results in periodic variation of the drug efficacy, our model is then a periodic time-dependent system. We get a threshold value between the extinction and the uniform persistence of the disease by applying the persistence theory. Our main results show that the disease goes to extinction if the threshold value is less than unity, whilst the disease persists if the threshold value is larger than unity. We also prove that there exists a positive periodic solution which is globally asymptotically stable. The threshold dynamics is in agreement with that for the system with constant coefficients, which extends the classic results for the corresponding autonomous model.     

Cross-diffusion induced Turing instability for a three species food chain model

In this paper, we study a strongly coupled reaction–diffusion system describing three interacting species in a food chain model, where the third species preys on the second one and simultaneously the second species preys on the first one. We first show that the unique positive equilibrium solution is globally asymptotically stable for the corresponding ODE system. The positive equilibrium solution remains linearly stable for the reaction–diffusion system without cross-diffusion, hence it does not belong to the classical Turing instability scheme. We further proved that the positive equilibrium solution is globally asymptotically stable for the reaction–diffusion system without cross-diffusion by constructing a Lyapunov function. But it becomes linearly unstable only when cross-diffusion also plays a role in the reaction–diffusion system, hence the instability is driven solely from the effect of cross-diffusion. Our results also exhibit some interesting combining effects of cross-diffusion, intra-species competitions and inter-species interactions.     

一类污染环境下具有脉冲输入的竞争培养模型的定性分析

本文研究了污染环境下具有脉冲输入的竞争培养模型.利用乘子理论和小振幅扰动法,我们得到了种群灭绝周期解全局渐近稳定的充分条件,同时还得到了种群持久的条件.我们的结果表明环境污染能最终导致种群灭绝.     

Global dynamics of a class of SEIRS epidemic models in a periodic environment

In this paper, we study a class of periodic SEIRS epidemic models and it is shown that the global dynamics is determined by the basic reproduction number R₀ which is defined through the spectral radius of a linear integral operator. If R₀<1, then the disease free periodic solution is globally asymptotically stable and if R₀>1, then the disease persists. Our results really improve the results in [T. Zhang, Z. Teng, On a nonautonomous SEIRS model in epidemiology Bull. Math. Biol. 69 (8) (2007) 2537-2559] for the periodic case. Moreover, from our results, we see that the eradication policy on the basis of the basic reproduction number of the time-averaged system may overestimate the infectious risk of the periodic disease. Numerical simulations which support our theoretical analysis are also given.     

Steady solution and its stability for Navier–Stokes equations with general Navier slip boundary condition

The steady solution and the asymptotic behavior of the corresponding nonsteady solution are studied for Navier–Stokes equations under the general Navier slip boundary condition. The existence of a unique stationary solution is established. It is also proved that this solution is asymptotically stable under some restrictions on the data. Bibliography: 16 titles. Dedicated to Vsevolod Alekseevich Solonnikov on the occasion of his jubilee Published in Zapiski Nauchnykh Seminarov POMI, Vol. 362, 2008, pp. 153–175.     

Dynamic analysis of pest control model with population dispersal in two patches and impulsive effect

In this paper, we investigate the pest control model with population dispersal in two patches and impulsive effect. By exploiting the Floquet theory of impulsive differential equation and small amplitude perturbation skills, we can obtain that the susceptible pest eradication periodic solution is globally asymptotically stable if the impulsive periodic τ is less than the critical value τ₀ . Further, we also prove that the system is permanent when the impulsive periodic τ is larger than the critical value τ₀. Hence, in order to drive the susceptible pest to extinction, we can take impulsive control strategy such that τ < τ₀ according to the effect of the viruses on the environment and the cost of the releasing pest infected in a laboratory. Finally, numerical simulations validate the obtained theoretical results for the pest control model with population dispersal in two patches and impulsive effect.     

一类具有抑制剂和质载的非均匀恒化器模型的共存解

研究了一类具有抑制剂和质载的非均匀恒化器模型.首先,采用锥映射上不动点指标理论得到了物种共存的充分条件.然后,根据度理论及摄动理论,研究了模型正平衡态解的唯一性和稳定性.结果表明当抑制剂的影响充分大时,模型存在唯一的渐近稳定的共存解.最后,利用比较原理和一致持续理论研究了系统的长时行为,并采用数值模拟的方法对所得结论进行了验证和补充.