Crowd evacuation simulation for bioterrorism in micro-spatial environments based on virtual geographic environments

Urban management requires assessing bioterrorism response in micro-spatial environments, modeling potential attacks and carrying out efficient risk assessment. This paper presents the method of crowd evacuation simulation for bioterrorism in micro-spatial environments using the basic theory of Virtual Geographic Environments (VGE), combined with pathogen diffusion and crowd simulation modeling techniques. A framework of evacuation simulation was presented in this paper and the key technologies to implement the framework, including grid-based spatial data environment, agent-based individual model, and the method of associated individual behavior with spatial environment were also proposed to simulating crowd behaviors in bioterrorism. Taking the Olympic Park station of the Beijing Metro Line 8 as a typical study area, a crowd evacuation simulation prototype system was developed and a quasi-experiment using three different scenarios was conducted. The prototype system can be used to demonstrate some emergent individual behaviors in bioterrorism, such as competitive, queuing, and herding. Details can be obtained at each computation step (e.g., the number of people in subway station, the region of population, the geo-location of individual, the exposed population in polluted areas) with the prototype system. In the experiments, the number of people exposed is constantly increasing with the gradually increase of contaminant area as time pass. And different scenes were appeared for the different way of deal with bioterrorism. With the experiment, the number of people affected and the relevant parameters under various bioterrorism scenarios can be estimated, which can support rapid and efficient emergency decision-making for bioterrorism prevention. (C) 2012 Elsevier Ltd. All rights reserved.