Pedestrian, Crowd and Evacuation Dynamics

Abstract

Collective intelligence Emergent functional behavior of a large number of people that results from interactions of individuals rather than from individual reasoning or global optimization. Crowd Agglomeration of many people in the same area at the same time. The density of the crowd is assumed to be high enough to cause continuous interactions with or reactions to other individuals. Crowd turbulence Unanticipated and unintended irregular motion of individuals into different directions due to strong and rapidly changing forces in crowds of extreme density. Emergence Spontaneous establishment of a qualitatively new behavior through non-linear interactions of many objects or subjects. Evolutionary optimization Gradual optimization based on the effect of frequently repeated randommutations and selection processes based on some success function (“fitness”). Faster-is-slower effect This term reflects the observation that certain processes (in evacuation situations, production, traffic dynamics, or logistics) take more time if performed at high speed. In other words, waiting can often help to coordinate the activities of several competing units and to speed up the average progress. Freezing-by-heating effect Noise-induced blockage effect caused by the breakdown of direction-segregated walking patterns (typically two or more “lanes” characterized by a uniform direction of motion). “Noise” means frequent variations of the walking direction due to nervousness or impatience in the crowd, e. g. also frequent overtaking maneuvers in dense, slowly moving crowds. Panic Breakdown of ordered, cooperative behavior of individuals due to anxious reactions to a certain event. Often, panic is characterized by attempted escape of many individuals from a real or perceived threat in situations of a perceived struggle for survival, which may end up in trampling or crushing of people in a crowd. Self-organization Spontaneous organization (i. e. formation of ordered patterns) not induced by initial or boundary conditions, by regulations or constraints. Self-organization is a result of non-linear interactions between many objects or subjects, and it often causes different kinds of spatio-temporal patterns of motion. Social force Vector describing acceleration or deceleration effects that are caused by social interactions rather than by physical interactions or fields.