Acknowledgments This work was supported by the National Natural Science Foundation of China (Grant No. 10647005) and Science and Technology Foundation of Guizhou Province, China (Grant No. 20090060).
In order to clarify the virus' spreading rules, a SIRS (Susceptible-Infected-Recovered-Susceptible) disease spread model based on sparsely distributed crowd is proposed. In this model, the effects of crowd-density,...