Study on the influencing mechanism of the obstacle layout to improve the pedestrian egress

参考我们去年进行的实验分析，我们今年开发了建模和仿真部分。在以往的实验中，障碍物造成了瓶颈，减少了行人可行走的宽度，不同的障碍物布局对应不同的出口效率。为了重现这一结果，我们开发了一种基于密度-流量基本图（FD）估算出口效率的数学方法。该方法将行走场景抽象为一种以瓶颈为链接，不同区域为节点的方案。我们成功地再现了不同布局下的出口时间，并由此估计了保持稳定出口效率的障碍物大小和障碍物出口宽度的合理范围。另一方面，我们根据真实的行人轨迹数据，探索了不同条件下FD的不同形状，因为FD的形状会影响仿真结果。具体而言，我们发现在火车站的高峰时段，可以观察到违反直觉的高密度-高速FD。我们预计高密度-高速FD是由于行人期望速度的变化，基于改进的基于agent的社会力模型的仿真结果支持这一观点，其中密度越大，速度越快。这表明，在探索障碍物的影响时，除了障碍物的几何布局外，关注行人的状态也很重要。

Referring to the experimental analysis we conducted last year, we developed the modeling and simulation part this year. In previous experiments, the obstacle created a bottleneck that reduced the pedestrian walkable width, and different obstacle layouts correspond to different egress efficiency. To reproduce this result, we developed a mathematical approach that estimates egress efficiency based on the density-flow rate fundamental diagram (FD). This approach abstracts the walking scenario as a scheme with bottlenecks as links and different regions as nodes. We successfully reproduced the egress times under different layouts, from which we estimated a reasonable range of obstacle size and obstacle-exit width that maintains stable egress efficiency.On the other hand, we explored the different shapes of the FD under various conditions based on real pedestrian trajectory data, as the shape of the FD affects the simulation results. Specifically, we found that during rush hours at railway stations, a counterintuitive high-density-high-velocity FD can be observed. We expect that the high-density-high-velocity FD is due to the variation of the pedestrian's desired velocity, which is supported by the simulation results based on a modified agent-based social force model, where higher density corresponds to a higher velocity. This suggests that, besides the geometrical layout of the obstacle, it is also significant to focus on the pedestrian's status when exploring the obstacle's influence.