Marek Bukáček

Experimental Study of Phase Transition in Pedestrian Flow

The transition between low and high density phases is a typical feature of systems with social interactions. This contribution focuses on simple evacuation design of one room with one entrance and one exit; four passing-through experiments were organized and evaluated by means of automatic image processing. The phase of the system, determined by travel time and occupancy, is evaluated with respect to the inflow, a controlled boundary condition. Critical values of inflow and outflow were described with respect to the transition from low density to congested state. Moreover, microscopic analysis of travel time is provided.

Experimental Analysis of Two-Dimensional Pedestrian Flow in Front of the Bottleneck

This contribution presents an experimental study of two-dimensional pedestrian flow with the aim to capture the pedestrian behaviour within the cluster formed in front of the bottleneck. Two experiments of passing through a room with one entrance and one exit were arranged according to phase transition study in Ezaki and Yanagisawa (Metastability in pedestrian evacuation. In: Cellular automata, ed. by G. Sirakoulis, S. Bandini. LNCS, vol 7495. Springer, Berlin/Heidelberg, pp 776–784, 2012), the inflow rate was regulated to obtain different walking modes. By means of automatic image processing, pedestrians’ paths are extracted from camera recordings to get actual velocity and local density. Macroscopic information is extracted by means of a virtual detector and leaving times of pedestrians. The pedestrian’s behaviour is evaluated by means of density and velocity. Different approaches of measurement are compared using several fundamental diagrams. Two phases of crowd behaviour have been recognized and the phase transition is described.

Cellular Model of Pedestrian Dynamics with Adaptive Time Span

A cellular model of pedestrian dynamics based on the Floor Field model is presented. Contrary to the parallel update in Floor Field, the concept of adaptive time span is introduced. This concept, together with the concept of bounds, supports the spontaneous line formation and chaotic queue in front of the bottleneck. Model simulations are compared to the experiment “passing through”, from which a phase transition from low to high density is observed.

Case Study of Phase Transition in Cellular Models of Pedestrian Flow

One room with one exit and one multiple entrance is modelled using 32 different settings and modifications of floor field model. The influence of following aspects are investigated in the scope of the transition from free flow to congestion phase with respect to the inflow rate: Heterogeneity/Homogeneity; With/Without bounds; Moore/von Neumann neighbourhood; Synchronous/Asynchronous update; High/Low friction. Considering the average travel time through the room and average room occupancy the settings incorporating the bounds and synchronous update seems to match the experimental data from the qualitative point of view.

Influence of agents heterogeneity in cellular model of evacuation

The influence of agents heterogeneity on the microscopic characteristics of pedestrian flow is studied via an evacuation simulation tool based on the Floor-Field model. The heterogeneity is introduced in agents velocity, aggressiveness, and sensitivity to occupation. The simulation results are compared to data gathered during an original experiment. The comparison shows that the heterogeneity in aggressiveness and sensitivity occupation enables to reproduce some microscopic aspects. The heterogeneity in velocity seems to be redundant.

Cellular Model of Room Evacuation Based on Occupancy and Movement Prediction

The rule-based CA for simulating the evacuation process of single room with one exit is presented. Analogically to the Floor-Field model, the presented model is based on the movement on rectangular lattice, driven by the potential field generated by the exit. Several ideas of decision-making allowing the agent to choose an occupied cell are implemented, to reflect the observed behaviour in high densities. The velocity of pedestrians is represented by the updating frequency of the individuals. To calibrate model parameters, an experiment “leaving the room” was organized. Based on the observed behaviour, the influence of parameters is discussed and several modifications are suggested.

Conflict Solution According to “Aggressiveness” of Agents in Floor-Field-Based Model

This contribution introduces an element of “aggressiveness” into the Floor-Field based model with adaptive time-span. The aggressiveness is understood as an ability to win conflicts and push through the crowd. From experiments it is observed that this ability is not directly correlated with the desired velocity in the free flow regime. The influence of the aggressiveness is studied by means of the dependence of the travel time on the occupancy of a room. A simulation study shows that the conflict solution based on the aggressiveness parameter can mimic the observations from the experiment.

Individual Microscopic Results of Bottleneck Experiments

This contribution provides a microscopic experimental study of pedestrian motion in front of the bottleneck, and explains the high variance of individual travel time by the statistical analysis of trajectories. The analysis shows that this heterogeneity increases with increasing occupancy. Some participants were able to reach lower travel times due to more efficient path selection and more aggressive behaviour within the crowd. Based on this observations, a linear model predicting travel time with respect to the aggressiveness of pedestrian is proposed.

Microscopic travel-time analysis of bottleneck experiments

ABSTRACT This contribution provides a microscopic experimental study of pedestrian motion in front of the bottleneck. The identification of individual pedestrians in variety of experiments enables to explain the high variance of travel time by the heterogeneity of the crowd. Some pedestrians are able to push effectively through the crowd, some get trapped in the crowd for significantly longer time. This ability to push through the crowd is associated with a slope of individual linear model of the dependency of travel time on the number of pedestrians in front of the bottleneck. Further detailed study of the origin of such ability is studied by means of the route choice, i.e. strategy whether to walk around the crowd or to walk directly through it. The study reveals that the ability to push through the crowd is a combination of aggressiveness in conflicts and willingness to overtake the crowd.

Advanced CA Crowd Models of Multiple Consecutive Bottlenecks

Simulation results from two advanced CA based crowd dynamics models, namely Social Distances Model and Bonds Floor Field Model, are investigated using experimental data. Two experiments regarding pedestrian egress from simple network of rooms with multiple consecutive bottlenecks were conducted in Prague and Krakow. Simulation results comparison is the basis for discussion about models properties.