Search

Virtual geographic environments (VGEs) are extensively used to explore the relationship between humans and environments. Crowd simulation provides a method for VGEs to represent crowd behaviors that are observed in the real world. The social force model (SFM) can simulate interactions among individuals, but it has not sufficiently accounted for inter-group and intra-group behaviors which are important components of crowd dynamics. We present the social group force model (SGFM), based on an extended SFM, to simulate group behaviors in VGEs with focuses on the avoiding behaviors among different social groups and the coordinate behaviors among subgroups that belong to one social group. In our model, psychological repulsions between social groups make them avoid with the whole group and group members can stick together as much as possible; while social groups are separated into several subgroups, the rear subgroups try to catch up and keep the whole group cohesive. We compare the simulation results of the SGFM with the extended SFM and the phenomena in videos. Then we discuss the function of Virtual Reality (VR) in crowd simulation visualization. The results indicate that the SGFM can enhance social group behaviors in crowd dynamics. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]