Modeling And Evacuation Of Pedestrian Dynamics Based On Markov Model

Urban rail transit is the main way to solve the problem of traffic jam in large cities.Building an urban rail transit system with convenient traffic,safe operation,and high efficiency and comfort is a major content of achieving harmonious urban traffic.In the commuter rush hours in urban rail transit,a large number of passengers gather in the station,leading to the jam.If passenger flow is not controlled and managed in time,it will seriously affect the subway operational efficiency and may cause security risks.To establish the correct pedestrian movement model for simulating the passenger movement and improving the evacuation efficiency in the emergency condition is a research hotspot in the field of urban rail transit.Therefore,based on the traffic characteristics of passenger flow of rail transit,the passengers' movement characteristics in the station and the evacuation of crowds under emergency conditions were studied.The specific research contents are as follows:Firstly,the movement behavior of passengers in the passage of the station was studied,and the pedestrian movement prediction based on a mixed Markov model was established according to the heuristic algorithm.In the model,the pedestrian chooses the moving direction according to the dynamic environment within the field of vision and selects the speed according to a principle for a Markov regime switching jump model.It not only realizes the information exchange between the pedestrian and the surrounding environment,but also reflects the randomness in the moving process.By simulation experiments and data collection,the parameters of the model were determined.The validity of the parameters of the model was verified.The basic curves of pedestrian speed-flow-density and the self-organizing phenomenon occurred in the simulation process were obtained.Secondly,the emergency evacuation of the crowd under normal vision conditions according to the pedestrian movement prediction based on a mixed Markov model was modeled and simulated.The pedestrians in the evacuation status were divided into rational pedestrians and pedestrians with crowd mentality.The crowd evacuation model with psychological factors was established and the model was verified.The parameters of the model were adjusted to study the evacuation characteristics of the crowd.The experimental results showed the relationship between the crowd proportion coefficient and the expected speed and the evacuation time.Then the "arching" phenomenon of crowding at the bottleneck was studied.The effects of pedestrians' visual field size of and the influence of the construction on the evacuation of the room were studied.The experimental results show that increasing the field size and setting a reasonable obstacle in the room can effectively increase the evacuation rate.Finally,taking into account the crowd evacuation characteristics under the invisible environments,a crowd evacuation model under an invisible environment was established according to the pedestrian movement prediction based on a mixed Markov model.The pedestrian path and crowd evacuation strategies under invisible environments were described by analyzing the walking rules in different areas of evacuation space.In addition,the evacuation behavior and evacuation time of crowds at different initial densities were studied.The effects of export indications,export width and quantity,and pedestrians' memory information on evacuation were studied to provide a decision-making basis for emergency evacuation management.