An epidemic models of SIR type and SIRS type with general contact rate and constant immigration of each class were discussed by means of theory of limit system and suitable Liapunov functions. In the absence of input ...An epidemic models of SIR type and SIRS type with general contact rate and constant immigration of each class were discussed by means of theory of limit system and suitable Liapunov functions. In the absence of input of infectious individuals, the threshold of existence of endemic equilibrium is found.For the disease-free equilibrium and the endemic equilibrium of corresponding SIR model, the sufficient and necessary conditions of global asymptotical stabilities are all obtained.For corresponding SIRS model, the sufficient conditions of global asymptotical stabilities of the disease-free equilibrium and the endemic equilibrium are obtained. In the existence of input of infectious individuals, the models have no disease-free equilibrium. For corresponding SIR model, the endemic equilibrium is globally asymptotically stable; for corresponding SIRS model, the sufficient conditions of global asymptotical stability of the endemic equilibrium are obtained.展开更多
Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte C...Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.展开更多
As the COVID-19 pandemic continues to spread, the global tourism industry is facing enormous challenges. There is an urgent need to explore an effective path for tourism to recover and revitalize. With the normalizati...As the COVID-19 pandemic continues to spread, the global tourism industry is facing enormous challenges. There is an urgent need to explore an effective path for tourism to recover and revitalize. With the normalization of the epidemic, tourism destinations will pay more attention to the prevention, warning, and coping strategies of the epidemic, and this focus will also be evident in the study of tourism destination resilience in the post-epidemic period. Some studies on the epidemic and the resilience of tourism are currently underway, but few of them are integrated with research on the resilience of tourism destinations in the post-epidemic period, although no systematic research ideas or methods have been found. Based on resilience theory, this paper summarizes the general research ideas and develops an epidemic resilience model suitable for urban tourism destinations. The present study also proposes a set of research methods based on the index system to analyze the resilience and its spatiotemporal dynamic characteristics of tourism destinations in the post-epidemic period. The methodology can be divided into three stages: Firstly, construct the conceptual model and evaluation system for tourism destination resilience;Secondly, select case sites for empirical analysis, measure the resilience of tourism destinations, and analyze the characteristics of spatiotemporal differences and subsequent factors of influence;And finally, establish an adaptive management mechanism for tourism destinations to use in response to the epidemic and in guiding the formulation of post-epidemic recovery policies.展开更多
2020年初的新冠肺炎疫情加速了全面网课时代到来。随着疫情防控取得阶段性胜利,各地高校逐渐回归并开启后疫情时代教学。后疫情时代,公共外语课不可能再延续以往的传统课程体系和教学模式,而要顺应教育信息化趋势,遵循结果导向(Outcome ...2020年初的新冠肺炎疫情加速了全面网课时代到来。随着疫情防控取得阶段性胜利,各地高校逐渐回归并开启后疫情时代教学。后疫情时代,公共外语课不可能再延续以往的传统课程体系和教学模式,而要顺应教育信息化趋势,遵循结果导向(Outcome Based Education,缩写为OBE)的教育理念,以“学生为中心”的产出设计原则反向进行教学设计和正向实施教学过程。基于OBE理念,本研究构建了地方普通高校公共外语三级课程体系,分别为一级重语言基础课程群、二级重素质培养课程群和三级服务学生发展需求课程群。三级立体化课程体系既是地方高校公共外语适应后疫情时代“互联网+教育”信息化教学改革的出发点,又充分体现了公共外语课程的OBE设计理念和“以学生为中心”的教学思想。展开更多
文摘An epidemic models of SIR type and SIRS type with general contact rate and constant immigration of each class were discussed by means of theory of limit system and suitable Liapunov functions. In the absence of input of infectious individuals, the threshold of existence of endemic equilibrium is found.For the disease-free equilibrium and the endemic equilibrium of corresponding SIR model, the sufficient and necessary conditions of global asymptotical stabilities are all obtained.For corresponding SIRS model, the sufficient conditions of global asymptotical stabilities of the disease-free equilibrium and the endemic equilibrium are obtained. In the existence of input of infectious individuals, the models have no disease-free equilibrium. For corresponding SIR model, the endemic equilibrium is globally asymptotically stable; for corresponding SIRS model, the sufficient conditions of global asymptotical stability of the endemic equilibrium are obtained.
基金supported by the National Natural Science Foundation and the President Fund from the Graduate School of the Chinese Academy of Sciences
文摘Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.
基金The Major Project of Beijing Social Science Foundation (19ZDA11)。
文摘As the COVID-19 pandemic continues to spread, the global tourism industry is facing enormous challenges. There is an urgent need to explore an effective path for tourism to recover and revitalize. With the normalization of the epidemic, tourism destinations will pay more attention to the prevention, warning, and coping strategies of the epidemic, and this focus will also be evident in the study of tourism destination resilience in the post-epidemic period. Some studies on the epidemic and the resilience of tourism are currently underway, but few of them are integrated with research on the resilience of tourism destinations in the post-epidemic period, although no systematic research ideas or methods have been found. Based on resilience theory, this paper summarizes the general research ideas and develops an epidemic resilience model suitable for urban tourism destinations. The present study also proposes a set of research methods based on the index system to analyze the resilience and its spatiotemporal dynamic characteristics of tourism destinations in the post-epidemic period. The methodology can be divided into three stages: Firstly, construct the conceptual model and evaluation system for tourism destination resilience;Secondly, select case sites for empirical analysis, measure the resilience of tourism destinations, and analyze the characteristics of spatiotemporal differences and subsequent factors of influence;And finally, establish an adaptive management mechanism for tourism destinations to use in response to the epidemic and in guiding the formulation of post-epidemic recovery policies.
文摘2020年初的新冠肺炎疫情加速了全面网课时代到来。随着疫情防控取得阶段性胜利,各地高校逐渐回归并开启后疫情时代教学。后疫情时代,公共外语课不可能再延续以往的传统课程体系和教学模式,而要顺应教育信息化趋势,遵循结果导向(Outcome Based Education,缩写为OBE)的教育理念,以“学生为中心”的产出设计原则反向进行教学设计和正向实施教学过程。基于OBE理念,本研究构建了地方普通高校公共外语三级课程体系,分别为一级重语言基础课程群、二级重素质培养课程群和三级服务学生发展需求课程群。三级立体化课程体系既是地方高校公共外语适应后疫情时代“互联网+教育”信息化教学改革的出发点,又充分体现了公共外语课程的OBE设计理念和“以学生为中心”的教学思想。
