采用动态背景场元胞自动机模型研究了双出口教室的人群疏散. 该模型将静态的障碍物分为不可穿越和可穿越两种, 行人被当作移动的障碍物, 因此背景场随人群的运动而变化. 行人通过比较两个出口在其当前所在位置产生的背景场值来选择目标出口. 通过数值模拟研究了不同出口宽度和桌椅排列下双出口教室的人群疏散过程, 得到了不同位置处的疏散时间分布以及平均和最大疏散时间的变化曲线. 模拟结果表明, 距离因素是学生选择出口的主要因素. 疏散开始时, 学生倾向于进入就近的过道. 疏散过程中, 少数中间的学生会由于目标出口的拥堵而选择另一出口. 当学生到达目标出口附近时, 通常不会再选择其他出口. 模拟结果与日常经验一致. 该模型可以用于具有复杂内部结构、多出口房间的人群疏散模拟.

A cellular automaton model based on a time-varying floor field is applied to investigate crowd evacuation from a classroom with two exits. In this model, static obstacles are classified into impassable ones and passable ones. As pedestrians are treated as movable obstacles, the floor field varies with the crowd movement. Each exit produces its floor field, and a pedestrian selects his/her target exit by comparing values of both fields in his/her position. Numerical simulations are performed to study the evacuation process in consideration of exit width and desk layouts. It is shown that the key factor of exit choice is the distance to each exit in the evacuation process. Initially students prefer to enter the nearest aisle. In an evacuation process, few students in the middle of the classroom turn to another exit due to the congestion near the previously selected exit. Once they are approaching their target exits, they usually do not change their choices again. It coincides with the daily experience. This model can be used to simulate crowd evacuation from a multi-exit room with complex inner structures.