School of Traffic and Transportation, Beijing Jiaotong University, 100044 Beijing, China.
Institute for Advanced Simulation, Forschungszentrum Jülich, 52425 Jülich, Germany.
Phys Rev E. 2018 May;97(5-1):052127. doi: 10.1103/PhysRevE.97.052127.
In a crowd, individuals make different motion choices such as "moving to destination," "following another pedestrian," and "making a detour." For the sake of convenience, the three direction choices are respectively called destination direction, following direction, and detour direction in this paper. Here, it is found that the featured direction choices could be inspired by the shape characteristics of the Voronoi diagram. To be specific, in the Voronoi cell of a pedestrian, the direction to a Voronoi node is regarded as a potential "detour" direction and the direction perpendicular to a Voronoi link is regarded as a potential "following" direction. A pedestrian generally owns several alternative Voronoi nodes and Voronoi links in a Voronoi cell, and the optimal detour and following direction are determined by considering related factors such as deviation. Plus the destination direction which is directly pointing to the destination, the three basic direction choices are defined in a Voronoi cell. In order to evaluate the Voronoi diagram based basic directions, the empirical trajectory data in both uni- and bi-directional flow experiments are extracted. A time series method considering the step frequency is used to reduce the original trajectories' swaying phenomena which might disturb the recognition of actual forward direction. The deviations between the empirical velocity direction and the basic directions are investigated, and each velocity direction is classified into a basic direction or regarded as an inexplicable direction according to the deviations. The analysis results show that each basic direction could be a potential direction choice for a pedestrian. The combination of the three basic directions could cover most empirical velocity direction choices in both uni- and bi-directional flow experiments.
在人群中，个体做出不同的运动选择，例如“前往目的地”、“跟随其他行人”和“绕道”。为了方便起见，本文将这三个方向选择分别称为目的地方向、跟随方向和绕道方向。在这里，发现特征方向选择可以受到 Voronoi 图形状特征的启发。具体来说，在行人的 Voronoi 单元中，到 Voronoi 节点的方向被视为潜在的“绕道”方向，与 Voronoi 链路垂直的方向被视为潜在的“跟随”方向。行人通常在 Voronoi 单元中拥有几个替代的 Voronoi 节点和 Voronoi 链路，最佳的绕道和跟随方向是通过考虑偏差等相关因素来确定的。再加上直接指向目的地的目的地方向，在 Voronoi 单元中定义了三个基本方向选择。为了评估基于 Voronoi 图的基本方向，从单向和双向流动实验中提取经验轨迹数据。使用考虑步频的时间序列方法来减少原始轨迹的摆动现象，这可能会干扰对实际前进方向的识别。研究了经验速度方向与基本方向之间的偏差，根据偏差将每个速度方向分类为基本方向或视为无法解释的方向。分析结果表明，每个基本方向都可能是行人的潜在方向选择。这三个基本方向的组合可以涵盖单向和双向流动实验中大多数经验速度方向的选择。
