A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,t...A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.展开更多
为了应对容迟网络中拓扑结构剧烈变化、节点间连接频繁中断等问题,报文通常采用"存储—携带—转发"的方式进行传输:节点将报文存储在缓存中,携带报文直到遇到合适的机会才将报文转发给其他节点.因为缓存有限,这样的传输方式...为了应对容迟网络中拓扑结构剧烈变化、节点间连接频繁中断等问题,报文通常采用"存储—携带—转发"的方式进行传输:节点将报文存储在缓存中,携带报文直到遇到合适的机会才将报文转发给其他节点.因为缓存有限,这样的传输方式会使节点缓存溢出,导致拥塞的发生.在容迟网络环境下提出一种基于生命游戏的拥塞控制策略(game of life based congestion control strategy in delay tolerant networks,GLCCS),并将其应用于Epidemic路由方式.GLCCS借鉴生命游戏的演化思想,依据邻居节点中持有特定报文的节点比例来决定节点本地缓存中相应报文的操作.同时还提出了基于全网信息的报文排队机制和丢弃策略,依据传递或者丢弃一个报文对整个网络投递成功率的影响,计算出报文的效用值,按照效用值对缓存中报文进行排队和丢弃.在机会网络模拟器ONE中对仿真移动模型和真实运动轨迹进行模拟,实验结果表明,GLCCS与其他拥塞控制策略相比提高了投递成功率,减小了网络时延、丢包率以及负载比率.展开更多
Tree topologies, which construct spatial graphs with large characteristic path lengths and small clustering coefficients, are ubiquitous in deployments of wireless sensor networks. Small worlds are investigated in tre...Tree topologies, which construct spatial graphs with large characteristic path lengths and small clustering coefficients, are ubiquitous in deployments of wireless sensor networks. Small worlds are investigated in tree-based networks. Due to link ad- ditions, characteristic path lengths reduce rapidly and clustering coefficients increase greatly. A tree abstract, Cayley tree, is con- sidered for the study of the navigation algorithm, which runs auto- matically in the small worlds of tree-based networks. In the further study, epidemics in the small worlds of tree-based wireless sen- sor networks on the large scale are studied, and the percolation threshold is calculated, at which the outbreak of the epidemic takes place. Compared with Cayley tree, there is a smaller percolation threshold suffering from the epidemic.展开更多
Stochastic switched epidemic systems with a discrete or distributed time delay are constructed and investigated. By the Lyapunov method and lto＇s differential rule, the existence and uniqueness of global positive sol...Stochastic switched epidemic systems with a discrete or distributed time delay are constructed and investigated. By the Lyapunov method and lto＇s differential rule, the existence and uniqueness of global positive solution of each system is proved. And stability conditions of the disease-free equilibrium of the systems are obtained. Numerical simulations are presented to illustrate the results.展开更多
基金Supported by National Natural Science Foundation of China(61911530398,12231012)Consultancy Project by the Chinese Academy of Engineering(2022-JB-06,2023-JB-12)+3 种基金the Natural Science Foundation of Fujian Province of China(2021J01621)Special Projects of the Central Government Guiding Local Science and Technology Development(2021L3018)Royal Society of Edinburgh(RSE1832)Engineering and Physical Sciences Research Council(EP/W522521/1).
文摘A stochastic epidemic model with two age groups is established in this study,in which the susceptible(S),the exposed(E),the infected(I),the hospitalized(H)and the recovered(R)are involved within the total population,the aging rates between two age groups are set to be constant.The existence-and-uniqueness of global positive solution is firstly showed.Then,by constructing several appropriate Lyapunov functions and using the high-dimensional Itô’s formula,the sufficient conditions for the stochastic extinction and stochastic persistence of the exposed individuals and the infected individuals are obtained.The stochastic extinction indicator and the stochastic persistence indicator are less-valued expressions compared with the basic reproduction number.Meanwhile,the main results of this study are modified into multi-age groups.Furthermore,by using the surveillance data for Fujian Provincial Center for Disease Control and Prevention,Fuzhou COVID-19 epidemic is chosen to carry out the numerical simulations,which show that the age group of the population plays the vital role when studying infectious diseases.
文摘为了应对容迟网络中拓扑结构剧烈变化、节点间连接频繁中断等问题,报文通常采用"存储—携带—转发"的方式进行传输:节点将报文存储在缓存中,携带报文直到遇到合适的机会才将报文转发给其他节点.因为缓存有限,这样的传输方式会使节点缓存溢出,导致拥塞的发生.在容迟网络环境下提出一种基于生命游戏的拥塞控制策略(game of life based congestion control strategy in delay tolerant networks,GLCCS),并将其应用于Epidemic路由方式.GLCCS借鉴生命游戏的演化思想,依据邻居节点中持有特定报文的节点比例来决定节点本地缓存中相应报文的操作.同时还提出了基于全网信息的报文排队机制和丢弃策略,依据传递或者丢弃一个报文对整个网络投递成功率的影响,计算出报文的效用值,按照效用值对缓存中报文进行排队和丢弃.在机会网络模拟器ONE中对仿真移动模型和真实运动轨迹进行模拟,实验结果表明,GLCCS与其他拥塞控制策略相比提高了投递成功率,减小了网络时延、丢包率以及负载比率.
基金supported by the National Natural Science Foundation of China (61104086) the National Defense Advanced Research Project of China (40405020401)
文摘Tree topologies, which construct spatial graphs with large characteristic path lengths and small clustering coefficients, are ubiquitous in deployments of wireless sensor networks. Small worlds are investigated in tree-based networks. Due to link ad- ditions, characteristic path lengths reduce rapidly and clustering coefficients increase greatly. A tree abstract, Cayley tree, is con- sidered for the study of the navigation algorithm, which runs auto- matically in the small worlds of tree-based networks. In the further study, epidemics in the small worlds of tree-based wireless sen- sor networks on the large scale are studied, and the percolation threshold is calculated, at which the outbreak of the epidemic takes place. Compared with Cayley tree, there is a smaller percolation threshold suffering from the epidemic.
基金supported by the National Natural Science Foundation of China(60874114)
文摘Stochastic switched epidemic systems with a discrete or distributed time delay are constructed and investigated. By the Lyapunov method and lto＇s differential rule, the existence and uniqueness of global positive solution of each system is proved. And stability conditions of the disease-free equilibrium of the systems are obtained. Numerical simulations are presented to illustrate the results.
