共查询到18条相似文献,搜索用时 125 毫秒
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研究了一类具非线性发生率和垂直传染的SEIR传染病模型,在模型中考虑了时滞和脉冲免疫接种,运用离散动力系统的频闪映射,获得了一个无病周期解,并得到了无病周期解全局吸引的条件,运用脉冲时滞泛函微分方程理论,获得了含有时滞的模型持久性的充分条件. 相似文献
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考虑的是带脉冲毒物输入和时滞的单种群模型的动力学行为,特别地,这里时滞项包含常时滞和分布成熟时滞.通过控制成熟个体的收获率,不仅得到了种群灭绝的充分条件,而且得到了种群灭绝周期解的指数渐近稳定和种群持久性的充分条件.这样的话,通过控制收获率,脉冲周期及脉冲毒物的输入量就能保护物种的数量,从而,结果对生物资源的管理具有一定的意义. 相似文献
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构建了具脉冲扰动的时滞Ivlev型捕食系统,获得了捕食者灭绝周期解全局渐近吸引和系统持续生存的充分条件.数值例子验证了理论结果,揭示了系统诸如吸引子突变,高倍周期振动,分支等复杂的动力学行为,最后进行了总结与讨论. 相似文献
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本文讨论了具有脉冲和无限时滞的模糊细胞神经网络的全局指数稳定性.通过建立一个脉冲时滞%积分微分不等式,以及模糊逻辑算子与M-矩阵的性质,不仅得到了系统全局指数稳定的充分条件,而且也给出了指数收敛速度.最后,所给的例子充分验证了文中所给出的充分条件的有效性. 相似文献
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本文考虑了一类在污染环境下具有时滞增长反应及脉冲输入营养基的恒化器模型.获得微生物灭绝周期解全局吸引的充分条件,并运用脉冲微分方程的相关理论和方法,证明了系统在适当的条件下是持久的,结论还表明该时滞是有害时滞. 相似文献
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Since the investigation of impulsive delay differential equations is beginning, the literature on delay epidemic models with pulse vaccination is not extensive. In this paper, we propose a new SEIRS epidemic disease model with two profitless delays and vertical transmission, and analyze the dynamics behaviors of the model under pulse vaccination. Using the discrete dynamical system determined by the stroboscopic map, we obtain a ‘infection-free’ periodic solution, further, show that the ‘infection-free’ periodic solution is globally attractive when some parameters of the model are under appropriate conditions. Using a new modeling method, we obtain sufficient condition for the permanence of the epidemic model with pulse vaccination. We show that time delays, pulse vaccination and vertical transmission can bring different effects on the dynamics behaviors of the model by numerical analysis. Our results also show the delays are “profitless”. In this paper, the main feature is to introduce two discrete time delays, vertical transmission and impulse into SEIRS epidemic model and to give pulse vaccination strategies. 相似文献
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In this paper, a new delay SIR epidemic model with pulse vaccination and incubation times is considered. We obtain an infection-free semi-trivial periodic solution and establish the sufficient conditions for the global attractivity of the semi-trivial periodic solution. By use of new computational techniques for impulsive differential equations with delay, we prove that the system is permanent under appropriate conditions. The results show that time delay, pulse vaccination and nonlinear incidence have significant effects on the dynamics behaviors of the model. Our results are illustrated and corroborated with some numerical experiments. 相似文献
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一类具时滞的中立型Lotka-Volterra模型的周期解 总被引:3,自引:0,他引:3
讨论了n种群时滞的中立型Lotka Volterra生态模型。利用新的重合度理论中连续性定理 ,得到了该模型正周期解存在性的充分条件 相似文献
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Dynamical analysis of a delayed singular prey–predator economic model with stochastic fluctuations 下载免费PDF全文
This article studies a delayed singular prey–predator economic model with stochastic fluctuations, which is described by differential‐algebraic equations due to a economic theory. Local stability and Hopf bifurcation condition are described on the delayed singular prey–predator economic model within deterministic environment. It reveals the sensitivity of the model dynamics on gestation time delay. A phenomenon of Hopf bifurcation occurs as the gestation time delay increases through a certain threshold. Subsequently, a singular stochastic prey–predator economic model with time delay is obtained by introducing Gaussian white noise terms to the above deterministic model system. The fluctuation intensity of population and harvest effort are calculated by Fourier transforms method. Numerical simulations are carried out to substantiate these theory analysis. © 2013 Wiley Periodicals, Inc. Complexity 19: 23–29, 2014 相似文献
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In this paper, we propose and analyze a nonautonomous predator-prey model with disease in prey, and a discrete time delay for the incubation period in disease transmission. Employing the theory of differential inequalities, we find sufficient conditions for the permanence of the system. Further, we use Lyapunov’s functional method to obtain sufficient conditions for global asymptotic stability of the system. We observe that the permanence of the system is unaffected due to presence of incubation delay. However, incubation delay affects the global stability of the positive periodic solution of the system. To reinforce the analytical results and to get more insight into the system’s behavior, we perform some numerical simulations of the autonomous and nonautonomous systems with and without time delay. We observe that for the gradual increase in the magnitude of incubation delay, the autonomous system develops limit cycle oscillation through a Hopf-bifurcation while the corresponding nonautonomous system shows chaotic dynamics through quasi-periodic oscillations. We apply basic tools of non-linear dynamics such as Poincaré section and maximum Lyapunov exponent to confirm the chaotic behavior of the system. 相似文献
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Yongli Song Tao Yin Hongying Shu 《Mathematical Methods in the Applied Sciences》2017,40(18):6451-6467
In this paper, we investigate the dynamics of a time‐delay ratio‐dependent predator‐prey model with stage structure for the predator. This predator‐prey system conforms to the realistically biological environment. The existence and stability of the positive equilibrium are thoroughly analyzed, and the sufficient and necessary conditions for the stability and instability of the positive equilibrium are obtained for the case without delay. Then, the influence of delay on the dynamics of the system is investigated using the geometric criterion developed by Beretta and Kuang. 26 We show that the positive steady state can be destabilized through a Hopf bifurcation and there exist stability switches under some conditions. The formulas determining the direction and the stability of Hopf bifurcations are explicitly derived by using the center manifold reduction and normal form theory. Finally, some numerical simulations are performed to illustrate and expand our theoretical results. 相似文献