In this paper a new model for the spread of sexually transmitted diseases （STDs） is presented. The dynamic behaviors of the model on a heterogenons scale-free （SF） network are considered, where the absence of a th...In this paper a new model for the spread of sexually transmitted diseases （STDs） is presented. The dynamic behaviors of the model on a heterogenons scale-free （SF） network are considered, where the absence of a threshold on the SF network is demonstrated, and the stability of the disease-free equilibrium is obtained. Three immunization strategies, uniform immunization, proportional immunization and targeted immunization, are applied in this model. Analytical and simulated results are given to show that the proportional immunization strategy in the model is effective on SF networks.展开更多
A new epidemic SIRS model with discrete delay on scale-free network is presented. We give the formula of the basic reproductive number for the model and prove that the disease dies out when the basic reproductive numb...A new epidemic SIRS model with discrete delay on scale-free network is presented. We give the formula of the basic reproductive number for the model and prove that the disease dies out when the basic reproductive number is less than unity, while the disease is uniformly persistent when the basic reproductive number is more than unity. Numerical simulations are given to demonstrate the main results.展开更多
The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully in...The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully instrumented with thermocouples, video cameras and gas extraction probes. The apartments were ignited successively whereupon the fire in the second apartment developed freely to post-flashover conditions and got the main focus in this report. The apartment was completely furnished with contemporary furniture and objects, and had an average fire load density for residential occupancy. A full description of the fire load, ventilation conditions and instrumentation are provided. The focus of this report is primarily to obtain conclusions on the horizontal spread of smoke throughout the apartment during the fire growth period. Velocities of smoke spreading were measured to be in the range below 0.05 m/s which means that the smoke migrated over the longest distance throughout the apartment for about 3 to 4 minutes while the flame did not leave the initial fire room. The main aim of the experiments was to collect a comprehensive set of data from a realistic and contemporary fire scenario to validate numerical simulations.展开更多
Based on the two-dimensional regular lattice,a modified SIS(Susceptible-Infected-Susceptible)epidemic model with motion rules is presented to study the spreading behavior on networks with dynamical topology.The mean-f...Based on the two-dimensional regular lattice,a modified SIS(Susceptible-Infected-Susceptible)epidemic model with motion rules is presented to study the spreading behavior on networks with dynamical topology.The mean-field theory is utilized to analyze the critical threshold(λc)of epidemic spreading under the randomly mixing conditions.It is found that λc is only related with the population density within the lattice.Large-scale numerical simulations are carried out to verify the mean-field results,and it is observed that the long-range probability p largely affects the epidemic spreading behavior.In addition,the effect of the dual time scales on epidemic spreading is also investigated by the simulations,and it is shown that the dual time scales accelerate the dynamic spreading behavior.The results indicate that the model with motion can help us to further understand the real epidemics.展开更多
文摘In this paper a new model for the spread of sexually transmitted diseases （STDs） is presented. The dynamic behaviors of the model on a heterogenons scale-free （SF） network are considered, where the absence of a threshold on the SF network is demonstrated, and the stability of the disease-free equilibrium is obtained. Three immunization strategies, uniform immunization, proportional immunization and targeted immunization, are applied in this model. Analytical and simulated results are given to show that the proportional immunization strategy in the model is effective on SF networks.
文摘A new epidemic SIRS model with discrete delay on scale-free network is presented. We give the formula of the basic reproductive number for the model and prove that the disease dies out when the basic reproductive number is less than unity, while the disease is uniformly persistent when the basic reproductive number is more than unity. Numerical simulations are given to demonstrate the main results.
文摘The apartment fire tests comprise a set of two full-scale fire experiments in a dwelling building made from pre-fabricated concrete elements in April 2013. Two apartments were nearly identically furnished and fully instrumented with thermocouples, video cameras and gas extraction probes. The apartments were ignited successively whereupon the fire in the second apartment developed freely to post-flashover conditions and got the main focus in this report. The apartment was completely furnished with contemporary furniture and objects, and had an average fire load density for residential occupancy. A full description of the fire load, ventilation conditions and instrumentation are provided. The focus of this report is primarily to obtain conclusions on the horizontal spread of smoke throughout the apartment during the fire growth period. Velocities of smoke spreading were measured to be in the range below 0.05 m/s which means that the smoke migrated over the longest distance throughout the apartment for about 3 to 4 minutes while the flame did not leave the initial fire room. The main aim of the experiments was to collect a comprehensive set of data from a realistic and contemporary fire scenario to validate numerical simulations.
基金Sponsored by the National Natural Science Foundation of China(Grant No.60904063,60774088 and 70871090)Tianjin Municipal Natural Science Foundation(Grant No.08JCZDJC21900)Science and Technology Development Foundation of University of Tianjin(Grant No.20090813)
文摘Based on the two-dimensional regular lattice,a modified SIS(Susceptible-Infected-Susceptible)epidemic model with motion rules is presented to study the spreading behavior on networks with dynamical topology.The mean-field theory is utilized to analyze the critical threshold(λc)of epidemic spreading under the randomly mixing conditions.It is found that λc is only related with the population density within the lattice.Large-scale numerical simulations are carried out to verify the mean-field results,and it is observed that the long-range probability p largely affects the epidemic spreading behavior.In addition,the effect of the dual time scales on epidemic spreading is also investigated by the simulations,and it is shown that the dual time scales accelerate the dynamic spreading behavior.The results indicate that the model with motion can help us to further understand the real epidemics.
