Exit dynamics of occupant evacuation in an emergency
Introduction
Along with the unceasing research on pedestrian flow and occupant evacuation, more and more researchers apply themselves to the research on individual behavior [1], [2] and a variety of phenomena resulting from collectivity behavior [3], [4] such as: jamming in traffic systems and granular materials [5], [6], [7], pedestrian behavior [8], [9], flocking in birds [10] and so on.
In order to find out the behavior of occupant evacuation at the exits of building, Ref. [11] used a simple rule of movement, namely, the occupant faces the vacant cell along the exit path and moves if where ϕ is a measure of his level of anxiety or panic (eagerness to move), otherwise he stays. L, R, and B are the total number of neighbors to the left, right and back directions of the cell, respectively. Other pedestrians who are separated from the cell by a vacant cell are not counted as neighbors.
As we know that evacuation process is quite complex and changeful, it is not suitable to simulate occupant evacuation with a deterministic rule. In order to approach the fact of evacuation, a particular two-dimensional Cellular Automata (CA) model based on the individual behavior is proposed.
Section snippets
Model description
The structure of the building is represented by a two-dimensional grid. Each cell can either be empty, occupied by an obstacle or occupied by one occupant. The size of a cell corresponds to 0.4×0.4 m2, which is the typical space occupied by an occupant in a dense crowd. In the model, each time step (ts) represents different real time of evacuation based on different walking velocity of occupant. For example, empirically the average velocity of an occupant in common condition is 1.0 m/s. Thus one
Simulation
In this paper, actual size of the side of each cell (0.4 m) is regarded as one unit, namely, the dimensionless size of the occupant is 1 and the dimensionless size of the room is the actual size divided by 0.4 m.
Generally, the range of occupants’ walking speed is between 0.5 and 1.5 m/s. It decreases with the increase of the density of occupants. Because of the dense distribution, the experiential value 0.8 m/s is regarded as the average walking speed. Therefore, one ts represents 0.5 s in this
Summary
In this paper, a two-dimensional CA random model is proposed to investigate the exit dynamics of occupant evacuation, which is regarded as a kind of collective motion caused by individual behavior. We have validated the phenomenon and conclusion proposed before: (1) there are optimal values of the exit width and the door separation; (2) arch, which indicates a jammed state will be formed at each exit door during evacuation. And the shape will change with the value of door separation. In
Acknowledgements
This paper was supported by the China NKBRSF project (no. 2001CB409603), National Natural Science Foundation of China (Grant no. 50276058) and the Important International Cooperate Project of NNSFC (no. 2003-50320120156). The authors deeply appreciate the supports.
References (20)
Saf. Sci.
(2001)Math. Comp. Simul.
(1985)- et al.
Physica A
(2001) - et al.
Physica A
(2002) - et al.
Fire Mater.
(1999) Nature
(2001)- et al.
Phys. Rev. E
(2001) - et al.
Phys. Rev. E
(1999) - et al.
Phys. Rev. Lett.
(2001) - et al.
Rev. Mod. Phys.
(1996)
Cited by (111)
Multi-agent modeling of crowd dynamics under mass shooting cases
2021, Chaos, Solitons and FractalsRobust scheduling for large scale evacuation planning
2020, Socio-Economic Planning SciencesCellular automaton model for social forces interaction in building evacuation for sustainable society
2020, Sustainable Cities and SocietyA dynamic impatience-determined cellular automata model for evacuation dynamics
2019, Simulation Modelling Practice and TheorySimulation of pedestrians’ evacuation dynamics with underground flood spreading based on cellular automaton
2019, Simulation Modelling Practice and Theory