A stochastic two-group SIR model is presented in this paper. The existence and uniqueness of its nonnegative solution is obtained, and the solution belongs to a positively invariant set. Further- more, the globally as...A stochastic two-group SIR model is presented in this paper. The existence and uniqueness of its nonnegative solution is obtained, and the solution belongs to a positively invariant set. Further- more, the globally asymptotical stability of the disease-free equilibrium is deduced by the stochastic Lyapunov functional method if R0 〈 1, which means the disease will die out. While if R0 〉 1, we show that the solution is fluctuating around a point which is the endemic equilibrium of the deterministic model in time average. In addition, the intensity of the fluctuation is proportional to the intensity of the white noise. When the white noise is small, we consider the disease will prevail. At last, we illustrate the dynamic behavior of the model and their approximations via a range of numerical experiments.展开更多
为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分...为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分组控制直流孤岛检测技术。同时,设计故障判据,并优化检测结果输出流程。通过实际案例验证,文章提出的方法能够在短时间内精准检测出故障,从而显著提升电源系统的运行稳定性。展开更多
基金Supported by National Natural Science Foundation of China (Grant No. 10971021)the Ministry of Education of China (Grant No. 109051)+1 种基金the Ph.D. Programs Foundation of Ministry of China (Grant No. 200918)the Graduate Innovative Research Project of NENU (Grant No. 09SSXT117)
文摘A stochastic two-group SIR model is presented in this paper. The existence and uniqueness of its nonnegative solution is obtained, and the solution belongs to a positively invariant set. Further- more, the globally asymptotical stability of the disease-free equilibrium is deduced by the stochastic Lyapunov functional method if R0 〈 1, which means the disease will die out. While if R0 〉 1, we show that the solution is fluctuating around a point which is the endemic equilibrium of the deterministic model in time average. In addition, the intensity of the fluctuation is proportional to the intensity of the white noise. When the white noise is small, we consider the disease will prevail. At last, we illustrate the dynamic behavior of the model and their approximations via a range of numerical experiments.
文摘为保障模块化串联结构电源系统的正常运行,探讨模块化串联结构电源系统中两级分组控制的故障检测策略。该方法通过优化模块化串联结构电源的故障反馈信号接收机制,引入基于最大功率点跟踪(Maximum Power Point Tracking,MPPT)的两级分组控制直流孤岛检测技术。同时,设计故障判据,并优化检测结果输出流程。通过实际案例验证,文章提出的方法能够在短时间内精准检测出故障,从而显著提升电源系统的运行稳定性。
