初始分布非均匀的疏散行人流实验研究和数学建模

Experimental features and mathematical model of pedestrian evacuation with asymmetrical pedestrian distribution

针对初始分布非均匀的行人流疏散问题,通过定义行人在行走过程中的方向模糊可视域,充分考虑了行人在方向可视域选择上的差异性;通过引入出口处行人密度,有效实现了建筑物内初始分布非均匀的行人流动态疏散演化过程;通过定义和标准化处理影响转移概率的因素,改进了场域元胞自动机模型,并将仿真结果与相关已知模型做了对比分析,研究结果表明,改进模型避免了对影响转移概率相关因素的权重依赖;系统疏散时间与方向模糊可视域和出口处行人分布区域大小有关;如果行人在疏散过程中拥有一个较大的视野,系统能够在出口处适中区域内通过电子屏、语音提示等方式实时提供行人密度,就能够有效提高整个系统的疏散效率.

Pedestrian＇s movement is a complex dynamic process because of the diversity in their psychological characteristics, such as cognitive, emotion, attitude and demand, etc. Simulation of pedestrian flow evacuation from a room with asymmetrical pedestrian distribution is presented based on the improved floor field cellular automata model in this paper. This model aims to define the direction fuzzy visual field to describe the difference of pedestrian＇s behavior in different environments, and present the region of pedestrian distribution in an exit to achieve the simulation of pedestrian flow evacuation with asymmetrical pedestrian distribution. When a pedestrian chooses the next target position, his behavior is affected by the repulsive force and the attractive force between pedestrians in direction fuzzy visual field, pedestrian＇s distribution in exits, and the shortest distance from a pedestrian to his target position. It simulates the scenes of a single exit and four exits in the condition of asymmetrical pedestrian distribution, and observes the self-organization phenomena in the process of simulation in order to reveal the inherent law of pedestrian flow evacuation with asymmetrical pedestrian distribution. Moreover, the simulation results of the improved and original models are compared and analyzed. The results indicate that the modified model can achieve the dynamic evacuation balance in the process of movement with asymmetrical pedestrian distribution. The improved model does not have to rely on the influence coefficient of every factor. Therefore, it avoids the subjectivity and the limitations of evacuation system in the process of making these factors. Evacuation time is related to radii of the direction fuzzy visual field and the region of pedestrian distribution in exits. If pedestrians can keep a lager radius of view in the direction fuzzy visual field and real-time master a moderate pedestrian＇s distribution of exits, these should effectively improve the evacuation efficiency of pedestrian flow. The present study is helpful for devising evacuation strategies and schemes in buildings that are similar to this pedestrian flow.