Threshold dynamics of a stage-structured single population model with non-transient and transient impulsive effects

In this paper, we present a stage-structured single population model with non-transient and transient impulsive effects. By the stroboscopic map theories of impulsive differential equations, we obtain the sufficient conditions for the permanence of the investigated system. The results indicate that the thresholds of the transient impulsive harvesting amount and the non-transient impulsive harvesting interval play important roles on the permanence of population. Our results also provide reliable tactic basis for the practical biological resource management.     

Global attractability and permanence for a new stage-structured delay impulsive ecosystem

In this paper, a new stage-structured delay ecosystem with impulsive effect is formulated and some dynamical properties of this system is investigated.By using comparison theorem and the stroboscopic technique, we prove the existence of the predator-extinction periodic solution of this system and obtain some sufficient conditions to guarantee the global attractivity of the prey-extinction periodic solution. In the final, we also obtain the permanence of this system. It should be pointed out that the new mathematical method used in this paper can also be applied to investigate such other ecosystems corresponding to both impulsive and delay differential equations.     

A single stage-structured population model with mature individuals in a polluted environment and pulse input of environmental toxin

In this paper, we concentrates on the study of a single stage-structured population model with mature individuals in a polluted environment and pulse input of environmental toxin. A globally attractive condition for the population-extinction boundary periodic solution of the investigated system is obtained. Sufficient criteria on the permanence of the population are derived.     

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.     

Positive periodic solutions for impulsive predator-prey model with dispersion and time delays

In this paper, we study the existence and global attractivity of positive periodic solutions for impulsive predator-prey systems with dispersion and time delays. By using coincidence degree theorem, a set of easily verifiable sufficient conditions are obtained for the existence of at least one strictly positive periodic solutions, and by means of a suitable Lyapunov functional, the uniqueness and global attractivity of positive periodic solution is presented. Some known results subject to the underlying systems without impulses are improved and generalized.     

Controllability analysis of linear time-varying systems with multiple time delays and impulsive effects

In this paper, the issue of controllability for linear time-varying systems with multiple time delays in the control and impulsive effects is addressed. The solution of such systems based on the variation of parameters is derived. Several sufficient and necessary algebraic conditions for two kinds of controllability, i.e., controllability to the origin and controllability, are derived. The relation among these conditions are established. A numerical example is provided to illustrate the effectiveness of the proposed methods.     

脉冲输入毒素对具有阶段结构的单种群生存影响的研究

研究了一类小容量污染环境中脉冲输入毒素对具有阶段结构的单种群生存问题,分别找到了种群生存与灭绝的阈值,利用不等式放缩技巧,得到了种群灭绝和持久生存的充分条件.利用MATLAB数值仿真,验证了理论结果的正确性,分析了毒素输入量,毒素输入周期及种群成长时间对种群生存的影响.     

Permanence and extinction of a nonautonomous impulsive plankton model with help

In this paper, we consider a nonautonomous impulsive plankton model with mutual help of preys. Sufficient conditions ensuring permanence and global attractivity of the model are established by the relation between solutions of impulsive system and corresponding nonimpulsive system. Also, we propose the conditions for which the species of system are driven to extinction. Numerical simulations are given to verify the main results.     

Epidemic dynamics model with delay and impulsive vaccination control base on variable population

Pulse vaccination is an effective strategy for the elimination of infectious diseases. In this paper, we considered an SEIR epidemic model with delay and impulsive vaccination direct at a variable population and analyzed its dynamic behaviors. Using the discrete dynamical system determined by the stroboscopic map, we obtain the exact infection‐free periodic solution of the impulsive epidemic system, further, prove that the infection‐free periodic solution is globally attractive if the vaccination rate is larger than θ* or the length of latent period of disease is larger than τ* or the length of period of impulsive vaccination is smaller than T*. We also prove that a short latent period of the disease (with τ) or a long period of pulsing (with T) or a small pulse vaccination rate (with θ) is sufficient to bring about the disease is uniformly persistent. Copyright © 2011 John Wiley & Sons, Ltd.     

具有脉冲毒素投放和营养再生的恒化器模型

研究具有脉冲毒素投放和营养再生的恒化器模型．利用脉冲微分方程的比较定理和小扰动方法得到了边界周期解全局渐近稳定的充分条件,进而得到了系统持续生存的充分条件．结果表明毒素环境将会导致微生物种群的灭绝．     

A stage-structured predator–prey model with disturbing pulse and time delays

In this article we propose a stage-structured predator–prey model with disturbing pulse and time delays and obtain the sufficient conditions for the global attractivity of predator-eradiation periodic solution and permanence of the system. We also show that time delay, pulse catching rate and the period of pulsing can affect the dynamics of the system.     

Persistence and extinction of a stochastic logistic model with delays and impulsive perturbation

A stochastic logistic model with delays and impulsive perturbation is proposed and investigated. Sufficient conditions for extinction are established as well as nonpersistence in the mean, weak persistence and stochastic permanence. The threshold between weak persistence and extinction is obtained. Furthermore, the theoretical analysis results are also derivated with the help of numerical simulations.     

Dynamics behaviors of a delayed stage-structured predator-prey model with impulsive effect

In this paper, we analyzed a delayed stage-structured predator-prey model with impulsive stocking on prey and continuous harvesting on predator. Sufficient conditions for the global attractivity of ‘predator-eradication’ periodic solution and permanence of the system are obtained. The results show that the behavior of impulsive stocking on prey plays an important role for the permanence of the system.     

Effect of pollution tax on population in a polluted environment

This paper establishes a mathematical model to study the long behavior of a single‐species population living in a polluted environment. In this paper, we suppose that pollution tax is imposed on toxicant emitters if their emission crosses the permissible limit, limit up to which there is no harm to the population. Some sufficient conditions for the persistence of the population are obtained. Copyright © 2011 John Wiley & Sons, Ltd.     

Qualitative analysis of hepatitis B virus infection model with impulsive vaccination and time delay

According to the epidemic state, propagation mode and transformation between HBV infection states,the Hepatitis B Virus (HBV) infection with impulsive vaccination and time delay are modelled and analyzed. The control methods of impulsive vaccination and active therapy are adopted. By using comparative theorem of impulsive differential equation, the sufficient conditions that Hepatitis B Virus will be eliminated eventually or be persistent are derived.     

Dynamics of an SI epidemic model with external effects in a polluted environment

In a polluted environment, considering the biological population infected with some kinds of diseases and hunted by human beings, we formulate two SI pollution-epidemic models with continuous and impulsive external effects, respectively, and investigate the dynamics of such systems. We assume that only the susceptible population is hunted by human beings. For the continuous system, we obtain sufficient conditions of the ultimate boundedness of solutions and the global asymptotical stability of equilibria. For the impulsive system, by using the comparison theorem and the analysis method, we show that under different conditions the disease-free periodic solution is globally asymptotically attractive, or the system is permanent. Numerical simulations confirm our theoretical results.     

The dynamics of a mutual interference age structured predator-prey model with time delay and impulsive perturbations on predators

In this paper, we introduce a mutual interference age structured predator-prey (natural enemy-pest) model with constant maturation time delay for the prey, and then propose a pest management strategy by constant periodic releasing for the predator. We show that there exists a global attractive pest-eradication periodic solution when the periodic releasing amount μ₁ and μ₂ are lager than some critical value. Further, to obtain a more effective pest control strategy, we give the conditions (involving the estimate of μ₁ and μ₂) in which the model is uniformly permanent and the pest population is under the economic threshold level. We believe that the results will provide reliable tactic basis for the practical pest management.     

Study of chemostat model with impulsive input and nutrient recycling in a polluted environment

In this paper, we introduce and study a Monod type chemostat model with nutrient recycling and impulsive input in a polluted environment. The sufficient and necessary conditions on the permanence and extinction of the microorganism are obtained. Two examples are given in the last section to verify our mathematical results. The numerical analysis show that if only the system is permanent, then it also is globally attractive.     

食饵具有流行病的阶段结构捕食模型

本文考虑了一类食饵具有流行病和阶段结构的脉冲时滞捕食模型．利用脉冲时滞微分方程的相关理论和方法，获得易感害虫根除周期解全局吸引的充分条件以及当脉冲周期在一定范围内时，天敌与易感害虫可以共存且易感害虫的密度可以控制在经济危害水平E（EIL）之下．我们的结论为现实的害虫管理提供了可靠的策略依据．     

Dynamical analysis of impulsive neural networks with time‐varying delays

In this work, a new criterion concerning the global exponential stability of impulsive neural networks with time‐varying delays is presented by employing the impulsive delayed differential inequality method. The criterion is independent of the time‐varying delays and does not require the differentiability of delay functions. An example and its simulation showing the effectiveness of the present criterion is given finally. Copyright © 2012 John Wiley & Sons, Ltd.