Biomimicry of Crowd Evacuation with a Slime Mould Cellular Automaton Model

Abstract

Evacuation is an imminent movement of people away from sources of danger. Evacuation in highly structured environments, e.g. building, requires advance planning and large-scale control. Finding a shortest path towards exit is a key for the prompt successful evacuation. Slime mould Physarum polycephalum is proven to be an efficient path solver: the living slime mould calculates optimal paths towards sources of attractants yet maximizes distances from repellents. The search strategy implemented by the slime mould is straightforward yet efficient. The slime mould develops may active traveling zones, or pseudopodia, which propagates along different, alternative, routes the pseudopodia close to the target loci became dominating and the pseudopodia propagating along less optimal routes decease. We adopt the slime mould’s strategy in a Cellular-Automaton (CA) model of a crowd evacuation. CA are massive-parallel computation tool capable for mimicking the Physarum’s behaviour. The model accounts for Physarum foraging process, the food diffusion, the organism’s growth, the creation of tubes for each organism, the selection of optimum path for each human and imitation movement of all humans at each time step towards near exit. To test the efficiency and robustness of the proposed CA model, several simulation scenarios were proposed proving that the model succeeds to reproduce sufficiently the Physarum’s inspiring behaviour.