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排序方式: 共有210条查询结果,搜索用时 156 毫秒
51.
In this paper, we study the global dynamics of a class of mathematical epidemiological models formulated by systems of differential equations. These models involve both human population and environmental component(s) and constitute high-dimensional nonlinear autonomous systems, for which the global asymptotic stability of the endemic equilibria has been a major challenge in analyzing the dynamics. By incorporating the theory of Volterra–Lyapunov stable matrices into the classical method of Lyapunov functions, we present an approach for global stability analysis and obtain new results on some three- and four-dimensional model systems. In addition, we conduct numerical simulation to verify the analytical results. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2014,19(4):830-841
This paper introduces an estimation method based on Least Squares Support Vector Machines (LS-SVMs) for approximating time-varying as well as constant parameters in deterministic parameter-affine delay differential equations (DDEs). The proposed method reduces the parameter estimation problem to an algebraic optimization problem. Thus, as opposed to conventional approaches, it avoids iterative simulation of the given dynamical system and therefore a significant speedup can be achieved in the parameter estimation procedure. The solution obtained by the proposed approach can be further utilized for initialization of the conventional nonconvex optimization methods for parameter estimation of DDEs. Approximate LS-SVM based models for the state and its derivative are first estimated from the observed data. These estimates are then used for estimation of the unknown parameters of the model. Numerical results are presented and discussed for demonstrating the applicability of the proposed method. 相似文献
55.
Hopf bifurcation in a predator-prey system with Holling type III functional response and time delays
Zizhen Zhang Huizhong Yang Ming Fu 《Journal of Applied Mathematics and Computing》2014,44(1-2):337-356
This paper is concerned with a delayed predator-prey system with modified Leslie-Gower and Holling type III schemes. By analyzing the associated characteristic equation, its local stability and the existence of periodic solutions via Hopf bifurcation with respect to both delays are obtained. Based on the normal form method and center manifold theorem, the formulaes for determining the direction of Hopf bifurcation and the stability of bifurcating periodic solutions are derived. Finally, some numerical simulations to illustrate the theoretical analysis are also carried out. 相似文献
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Kangbok Lee Joseph Y-T. Leung Zhao-hong Jia Wenhua Li Michael L. Pinedo Bertrand M.T. Lin 《European Journal of Operational Research》2014
We consider parallel machine scheduling problems where the processing of the jobs on the machines involves two types of objectives. The first type is one of two classical objective functions in scheduling theory: either the total completion time or the makespan. The second type involves an actual cost associated with the processing of a specific job on a given machine; each job-machine combination may have a different cost. Two bi-criteria scheduling problems are considered: (1) minimize the maximum machine cost subject to the total completion time being at its minimum, and (2) minimize the total machine cost subject to the makespan being at its minimum. Since both problems are strongly NP-hard, we propose fast heuristics and establish their worst-case performance bounds. 相似文献
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汪凯 《数学物理学报(A辑)》2009,29(3):794-799
该文利用重合度理论研究了一类具有分布时滞的高阶中立型泛函微分方程的周期解问题,得到了周期解存在的简单判别条件. 相似文献
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建立了考虑潜伏期时滞和临时免疫期时滞的具有混合隔离策略的非线性计算机病毒传播模型,旨在帮助理解计算机病毒在网络中的传播规律。通过计算模型基本再生数,以不同时滞组合为分岔参数,研究了模型的局部渐近稳定性;利用中心流形定理和规范型理论分析了Hopf分岔的方向和周期解的稳定性,并通过数值模拟验证了理论分析的正确性。研究结果可为计算机病毒治理提供理论依据。 相似文献