共查询到20条相似文献，搜索用时 250 毫秒
1.
考虑肺部感染初始先天系统反应的动态模型,首先根据三次多项式方程根的判别式,得到了模型有正平衡点的条件,其次利用平衡点稳定性理论和中心流形定理讨论了在该条件下模型正平衡点的具体类型及稳定性,最后考虑了在平衡点处出现的鞍结点分支. 相似文献
2.
杨纪华 《宁夏师范学院学报》2011,32(3):4-9
研究了具时滞电磁轴承系统的数学模型.从对系统线性化方程的特征方程根的分布分析入手,讨论了系统平衡点的稳定性条件,进而确定了系统平衡点的线性稳定性区域,然后又讨论了系统Hopf分支的存在性.最后,通过数值模拟验证了得到的结论. 相似文献
3.
研究了一类具收获率的功能性反应两种群模型,运用微分方程稳定性理论,确定了捕食系统模型的平衡点,得到了该系统正平衡点在第一象限的全局稳定性条件。 相似文献
4.
研究一类具有相互干扰功能反应的捕食-食饵系统.对正平衡点的局部渐近稳定性和全局稳定进行了详细说明,证明了系统在正平衡点处是全局稳定的,并利用Pontrjagin最大值原理及最优控制理论,得到该系统的最优捕获策略.所得结果改进和推广了相关文献的主要结果. 相似文献
5.
研究了一类具有食饵避难的Leslie-Gower捕食与被捕食系统的收获模型,讨论了平衡点的稳定性,考虑对食饵种群进行捕获,利用Hurwitz判据,得到了系统平衡点局部渐进稳定的充分条件,最后使用Pontryagin最大值原理得到了最优收获策略. 相似文献
6.
建立了具有时滞及非线性发生率的SIQR传染病模型,通过对无病平衡点和正平衡点处的特征方程的讨论,可得到在这两个平衡点处的局部渐近稳定性,进而得到了系统在两个平衡点处的全局渐近稳定性. 相似文献
7.
主要考虑平面系统极限集的性质,利用平衡点的稳定性,研究了Poincare-Bendixson定理,得到如下定理:若在系统的平衡点处满足af1/ax af2/ay│p≠0,则有界区域内半轨线的极限集只可能是以下二类型之一(1)单平衡点集(2)闭轨线. 相似文献
8.
甘乃峰 《鞍山师范学院学报》2017,(6):1-7
研究了一类具有初值的高阶差分方程系统平衡点的稳定性问题,得到了平衡点处稳定、局部渐近稳定性、全局渐近稳定性的充分条件,讨论了正平衡点处解的振动性问题. 相似文献
9.
10.
王红飞 《中国科教创新导刊》2009,(22):39-40
本文建立和研究了一类禽流感传染病动力学模型.模型中人类群体是SIR模型,禽类群体是SI模型.在建立模型时,考虑了人类易感者和禽类染病者之间联系.通过分析,得到了无病平衡点和地方病平衡点的局部稳定性和全局渐近稳定条件;并得到了疾病流行与否的阈值. 相似文献
11.
对四方格子上的具有决定性倒塌过程和随机倒塌过程的二维米堆模型的临界行为进行了数值模拟研究.系统经一个暂态过程后达到一个临界态,其雪崩大小的概率统计分布服从幂次规律.决定性倒塌模型和随机倒塌模型不属于同一个普适类,决定性模型的临界雪崩指数为τs=1.09±0.02,τa=1.10±0.02和τt=1.14±0.02.随机模型的临界雪崩指数为τs=1.25±0.02,τa=1.29±0.02和τt=1.40±0.02. 相似文献
12.
A minimax optimal control strategy for quasi-Hamiltonian systems with bounded parametric and/or external disturbances is proposed based on the stochastic averaging method and stochastic differential game. To conduct the system energy control, the partially averaged Ito stochastic differential equations for the energy processes are first derived by using the stochastic averaging method for quasi-Hamiltonian systems. Combining the above equations with an appropriate performance index, the proposed strategy is searching for an optimal worst-case controller by solving a stochastic differential game problem. The worst-case disturbances and the optimal controls are obtained by solving a Hamilton-Jacobi-Isaacs （HJI） equation. Numerical results for a controlled and stochastically excited DulTlng oscillator with uncertain disturbances exhibit the efficacy of the proposed control strategy. 相似文献
13.
In this study on the nature of pressure signals generated by a deterministic or stochastic process in a bubbling fluidized
bed, pressure fluctuation measurements were carried out in a 300-mm-diamet column at 0.090 m and 0.40 m above the distributor
for different gas velocities. The method of detecting deterministic dynamic underlying pressure signals is proposed on the
basis of predictability of pressure fluctuations. The deterministic nature of dynamics in fluidizing system was verified.
The deterministic level of dynamics in fluidizing system was analyzed for different locations of pressure measurements and
different gas velocities.
Project supported by the Science and Engineering Foundation of SINOPEC, China (X599029) 相似文献
14.
研究了资源量bi为随机变量的多目标随机线性规划问题,指出了多目标规划问题的目标一般不是同等重要的,针对多目标模糊线性规划问题,利用模糊集合理论建立了相应等价的确定性加权模糊随机规划模型。算例表明本文给出的模型算法是有效的,具有广泛的应用价值。 相似文献
15.
KE Hai-sen YE Xu-dong 《浙江大学学报(A卷英文版)》2006,7(10):1742-1747
INTRODUCTION In recent years, much progress has been made in the design of control laws for systems subjected to nonholonomic constraint making it impossible to stabilize the system by any time-invariant continuous state feedback control law. This fact stimulates re- searchers to construct time-varying (Jiang and Ni- jmeijer, 1999; Jiang, 2001; Samson, 1995; Tian and Li, 2002) or discontinuous (Chang and Chen, 2002; Ge et al., 2003; Hu et al., 2004; Kim and Tsiotras, 2002; Mnif, 2004;… 相似文献
16.
针对具有时延非线性系统提出一种神经网络预测控制．相应的预测模型通过递阶遗传算法离线训练数据并实时多步递推得到;性能函数中引入模型误差校正以克服模型失配及干扰等对系统造成的影响．仿真结果表明该系统具有良好动态响应及鲁棒性． 相似文献
17.
研究了由随机噪声反射布朗运动干扰的非线性系统dx(t)=f(x)(t)dt的随机稳定化,建立了受干扰系统的几乎必然指数稳定性判定性定理并估计了相应的样本Lyapunov指数。 相似文献
18.
A rectangular thin plate vibration model subjected to inplane stochastic excitation is simplified to a quasinonintegrable Hamiltonian system with two degrees of freedom. Subsequently a one-dimensional Ito? stochastic differential equation for the system is obtained by applying the stochastic averaging method for quasi-nonintegrable Hamiltonian systems. The conditional reliability function and conditional probability density are both gained by solving the backward Kolmogorov equation numerically. Finally, a stochastic optimal control model is proposed and solved. The numerical results show the effectiveness of this method. 相似文献
19.
Jun-hai SHI Zhi-dan ZHONG Xin-jian ZHU Guang-yi CAO 《浙江大学学报(A卷英文版)》2008,9(3):401-409
This study presents a robust design method for autonomous photovoltaic （PV）-wind hybrid power systems to obtain an optimum system configuration insensitive to design variable variations. This issue has been formulated as a constraint multi-objective optimization problem, which is solved by a multi-objective genetic algorithm, NSGA-II. Monte Carlo Simulation （MCS） method, combined with Latin Hypercube Sampling （LHS）, is applied to evaluate the stochastic system performance. The potential of the proposed method has been demonstrated by a conceptual system design. A comparative study between the proposed robust method and the deterministic method presented in literature has been conducted, The results indicate that the proposed method can find a large mount of Pareto optimal system configurations with better compromising performance than the deterministic method. The trade-off information may be derived by a systematical comparison of these configurations, The proposed robust design method should be useful for hybrid power systems that require both optimality and robustness. 相似文献
20.
探讨了用目标函数的经验均值代替目标函数求解有补偿二阶段问题的方法，将随机最优化问题转化为容易求解的确定性优化问题．不要求了解所涉及的随机变量的分布函数是该方法的特点． 相似文献