Investigation On Voronoi Diagram Based Pedestrian Models And Circle Antipode Experiments

With the continuous development of urbanization and the increasing frequency of large-scale activities,the safety,efficiency and comfort of pedestrian walking has attracted more attention from researchers.As a typical interdisciplinary research field,the study of pedestrian dynamics often requires the combination of psychology,behavioral science,physics,operational research,computer science and other disciplines.The common research methods of pedestrian dynamics include the simulation based on the understanding of pedestrian movement mechanism,and the investigation based on empirical data.Taken together,the main researches of this manuscript are introduced as follows:(1)The theory of pedestrian behaviors based on Voronoi diagram is proposed and verified.The Voronoi diagram has some unique geometric properties that can be used to define or study the relevant features of pedestrian movement,such as personal space,following/detour direction choices and neighbors.In order to better study relevant theories based on Voronoi diagram,this paper further studies the rule of direction choices in pedestrian movement through experimental trajectory data.It is found that the characteristic directions based on Voronoi diagram can be used to describe the direction choices in realistic,and it contributes to the modeling of pedestrian dynamics.(2)Several Voronoi diagram based pedestrian models are constructed.In this part,the Voronoi diagram based models are respectively formulated based on the social force model and heuristic model.In the modified social force model,the Voronoi diagram based detour direction is regarded as an alternative direction of the original self-driving direction pointing to the target point.The combination of the orginal direction and the detour direction contributes to the improvement of the pedestrian detour behaviors.In the modified heuristic model,three characteristic directions,i.e.destination direction,detour direction and adjustment direction,are proposed.The pedestrian will further consider the effect of local density and choose the most reasonable motion direction from the characteristic behavior directions.Both of the improved models can obtain well-agreed fundamental diagram and common self-organization phenomena,and more reasonable simulation results are obtained than the original model.(3)A macroscopic pedestrian motion network is proposed.Based on the Voronoi diagram and the Delaunay diagram,the pedestrian macroscopic motion network is constructed with the following behavior,detour behavior,and destination behavior.The motion network can reflect the macroscopic route choice behavior of pedestrians.At the same time,a macro and micro dynamic model based on the motion network is also formulated with the combination of the microscopic velocity choice behaviors and the macroscopic route choice behavior.More real and reasonable simulation results in dealing with pedestrian conflicts and macro-path navigation of complex scenes are obtained.(4)The circle antipode experiments were organized and investigated.The characteristics of the intense conflicts and the symmetrical experimental condition in the circle antipode experiments benefit the investigation of the collision avoidance mechanism and path navigation behavior of pedestrians.Through recognition and quantitative analysis of the real trajectories in the experiments,it was found that 1)the pedestrians in the experiment tend to walk on the right side.2)The route length is as the law of log-normal distribution,the route potential obeys the exponential distribution,andthe travel time is normally distributed as well as the speed.3)Taking the short routes unexpectedly cost pedestrians plenty of travel time,while detour seems to be a time－saving decision.(5)The macroscopic parameter evaluation framework of pedestrian model is designed and tested.Based on the serious conflict and symmetric distribution of the pedestrian circle antipode experiments,a set of pedestrian macroscopic parameter evaluation system is designed in this paper.The evaluation system mainly includes six evaluation indexes,namely,distribution of route length,distribution of route potential,distribution of travel time,distribution of individual speed,time series of average speed,and time series center distance.Evaluation methods based on K-S(Kolmogorov-Smirnov)test and DTW(Dynamic Time Warping)method are respectively formulated for the distribution index and time series distribution.Through the test of social force model and heuristic model,it is found that the evaluation framework can be used to evaluate the pedestrian model and reflect the differences between the pedestrian models.(6)A pedestrian dynamics simulation and analysis system is developed.The system integrates the simulation method with the empirical analysis method,and it can realize 1)real-time simulation based on pedestrian dynamics model.Namely,by initializing the pedestrian and scene,the pedestrian status is updated continuously based on the existing traditional model or custom model,and the simulation results of the pedestrian model are studied in real time.2)Visual analysis based on pedestrian trajectory data.Relevant features of pedestrian movement are studied and analyzed through the introduction of empirical pedestrian trajectories or simulated pedestrian trajectories.The development of this open source system can provide help for the modeling of pedestrian dynamics and the theoretical study of pedestrian movement.