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噪声和捕捞对捕食生态系统稳定性的影响
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作者 董庆国 宁丽娟 《动力学与控制学报》 2015年第4期314-320,共7页
讨论了在色噪声激励下,具有独立常数率捕捞和庇护所效应的捕食生态系统的稳定性问题.在弱扰动假设下应用Stratonovich-Khasminskii随机平均原理分别得到了两个物种的稳态概率密度,并研究了捕捞强度E1,色噪声强度Kii,谱宽和噪声相关时间... 讨论了在色噪声激励下,具有独立常数率捕捞和庇护所效应的捕食生态系统的稳定性问题.在弱扰动假设下应用Stratonovich-Khasminskii随机平均原理分别得到了两个物种的稳态概率密度,并研究了捕捞强度E1,色噪声强度Kii,谱宽和噪声相关时间对两个物种的稳态概率密度的影响.Monte-Carlo模拟验证理论求解的合理性.研究表明:1)随着捕捞活动的增大,随机因素对生态系统的影响逐渐减弱;2)噪声强度越大,生态系统越不稳定;3)随机激励的谱带越宽,生态系统越稳定;4)随机激励的相关时间越小,生态系统越稳定. 展开更多
关键词 色噪声 常数率捕捞 随机平均方法 稳态概率密度
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Discrete-Time Mean-Field Stochastic H_2/H_∞ Control 被引量:2
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作者 ZHANG Weihai MA Limin ZHANG Tianliang 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2017年第4期765-781,共17页
The finite horizon H_2/H_∞ control problem of mean-field type for discrete-time systems is considered in this paper. Firstly, the authors derive a mean-field stochastic bounded real lemma(SBRL). Secondly, a sufficien... The finite horizon H_2/H_∞ control problem of mean-field type for discrete-time systems is considered in this paper. Firstly, the authors derive a mean-field stochastic bounded real lemma(SBRL). Secondly, a sufficient condition for the solvability of discrete-time mean-field stochastic linearquadratic(LQ) optimal control is presented. Thirdly, based on SBRL and LQ results, this paper establishes a sufficient condition for the existence of discrete-time stochastic H_2/H_∞ control of meanfield type via the solvability of coupled matrix-valued equations. 展开更多
关键词 Discrete-time systems H2/H∞ control mean-field.
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First-passage failure of MDOF nonlinear oscillator 被引量:1
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作者 XU Ming JIN XiaoLing HUANG ZhiLong 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第8期1999-2006,共8页
First-passage failure of multiple-degree-of-freedom nonlinear oscillators with lightly nonlinear dampings and strongly nonlinear stiffness subject to additive and/or parametric Gaussian white noise excitations is stud... First-passage failure of multiple-degree-of-freedom nonlinear oscillators with lightly nonlinear dampings and strongly nonlinear stiffness subject to additive and/or parametric Gaussian white noise excitations is studied. First, by using the stochastic averaging method based on the generalized harmonic functions, the averaged It stochastic differential equation for the amplitudes of the nonlinear oscillators can be derived. Then the associated backward Kolmogorov equation of the conditional reliability function is established, and the conditional reliability is approximately expressed as a series expansion in terms of Kummer functions with time-dependent coefficients. By using the Galerkin method, the time dependent coefficients of the associated conditional reliability function can be solved by a set of differential equations. Finally, the proposed procedure is applied to Duffing-Van der Pol systems under external and/or parametric excitations of Gaussian white noises. The results are also verified by those obtained from Monte Carlo simulation of the original system. The effects of system parameters on first-passage failure are discussed briefly. 展开更多
关键词 first-passage stochastic averaging method generalized harmonic function Kummer function Galerkin method
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