Search

Abstract: When the microscopic pedestrian models, in which pedestrian space is continuously represented, are used to simulate pedestrian movement in the buildings with internal obstacles, some issues arise and need be dealt with in detail. This paper discusses two of the issues, namely formulating the desired direction of each pedestrian in the buildings and determining the region around each pedestrian, other individuals and obstacles in which affect his or her movement. The methods for computing the desired direction and effect region are proposed, using the algorithms for the potential of pedestrian space. By numerical experiments, the performance results of three proposed formulae for the desired direction are compared, the method for the effect region is tested, and the validity of the method for computing the desired direction as considering the border effect of obstacles is verified. Numerical results indicate that the proposed methods can be used to formulate pedestrian movement, especially in the buildings with internal obstacles, in the microscopic models with continuous space representation. [Copyright &y& Elsevier]

Abstract: The route choice of pedestrians during evacuation under conditions of both good and zero visibility is investigated using a group of experiments conducted in a classroom, and a microscopic pedestrian model with discrete space representation. Observation of the video recordings made during the experiments reveals several typical forms of behavior related to preference for destination, effect of capacity, interaction between pedestrians, following behavior and evacuation efficiency. Based on these forms of behavior, a microscopic pedestrian model with discrete space representation is developed. In the model, two algorithms are proposed to describe the movement of pedestrians to a destination under conditions of both good and zero visibility, respectively. Through numerical simulations, the ability of the model to reproduce the behavior observed in the experiments is verified. The study is helpful for devising evacuation schemes and in the design of internal layouts and exit arrangements in buildings that are similar to the classroom. [Copyright &y& Elsevier]

We propose a pedestrian position update rule, which is added to a microscopic pedestrian model to avoid pedestrian overlap. In the rule, the step size of a pedestrian moving in a selected direction at each update is in inverse proportion to the repulsive actions imposed by other pedestrians moving in a direction with an exponential rate. The positions of the pedestrians are then updated in each small time interval. In this way, a barrier between the pedestrians can be generated, and after updating their positions the pedestrians do not overlap with each other. The modified model is compared to the original model through a simulation of the evacuation process of pedestrians in a closed area. The simulation results indicate that the modified model is superior to the original model in several aspects. [ABSTRACT FROM AUTHOR]

Abstract: We present a method of predicting pedestrian route choice behavior and physical congestion during the evacuation of indoor areas with internal obstacles. Under the proposed method, a network is first constructed by discretizing the space into regular hexagonal cells and giving these cells potentials before a modified cell transmission model is employed to predict the evolution of pedestrian flow in the network over time and space. Several properties of this cell transmission model are explored. The method can be used to predict the evolution of pedestrian flow over time and space in indoor areas with internal obstacles and to investigate the collection, spillback, and dissipation behavior of pedestrians passing through a bottleneck. The cell transmission model is further extended to imitate the movements of multiple flows of pedestrians with different destinations. An algorithm based on generalized cell potential is also developed to assign the pedestrian flow. [Copyright &y& Elsevier]

Abstract: Considering such a fact that the traffic demand freshly entering a network does not have perfect information about traffic condition and then might choose travel routes randomly, we propose an improved network traffic flow evolution model in this article. The model''s properties and fixed points are investigated. The fixed points of the model, which are different from traditional user equilibrium state or part user equilibrium state, can better formulate the result of traffic flow assignment in realization. Simulation results obtained from a grid network show that the model can be used to approximately model the process of realizing user equilibrium state, the network flow can indeed evolve to one or more fixed points, and the initial values of all available path flows can be zero. [Copyright &y& Elsevier]