DEM-based Group Behaviour Model and Its Impact in Tsunami Evacuation Simulation

Abstract

Most of the existing crowd behavior models simulate crowd motions based on interactions among isolated walking individuals. In reality, a crowd not only contains individuals who walk alone, but walk in groups as well. Hence, the interactions should be extended among individuals who belong to the same group as well as among individuals and different groups’ persons. Limited number of works has incorporate group behavior in crowd behavior models. This topic is still new and its impact in crowd dynamics is more to be discovered. Driven by the belief of group behavior modeling can lead to a more realistic crowd motions, this paper is objectively to model group behavior in crowd behavior simulation and its impact in tsunami evacuation process. For this, observations and video footages of public area had been conducted as a basis of group behavior model development. Relying on observations made, the existing Distinct Element Method (DEM)-based Crowd Behavior Simulator for Disaster Evacuation (CBS-DE) is extended to incorporate group behavior by introducing in-group and out-group interactions. Validation on the extended CBS-DE was executed in two stages work; (1) looking for a suitable grouping scenario from the observations conducted; and (2) the simulation of a suitable scenario in (1). It shows that the CBS-DE with group behavior model can realistically simulate group behavior. Later, the new model was demonstrated in the simulation of tsunami evacuation process. The effects of the group behavior model were shown in the context of evacuation completion time by comparison with the CBS-DE without group behavior model. Keywords: DEM, group behaviour, in-group interaction, out-group interaction