Collective Dynamics (E-Journal)
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Analysis on Alighting and Boarding Movement Laws in Subway Using Modified Social Force Model
Full text linkThis paper presents a multi-agent simulator based on social force model to simulate each passenger’s boarding and alighting behavior both in a train and on a platform seamlessly. Passengers can be divided into three types: to board, alight and stay in train. They have different individual attributes and follow different walking rules. Due to the characteristics of subway environment and passengers' behavior in boarding and alighting, some adjustment and improvement were made to the basic social force model: (1) In some cases during the process of boarding and alighting, the driving force targeting to destination needs to be doubled, and the repulsion force between two agents needs to be reduced. (2) Passengers who stay in the train show quite different movement from the usual pedestrian. They usually want to remain still, unless they are in front of the door. To describe their behaviors, we introduced a tangent detour force. The scope of the interaction between agents is extended and some passengers out of the visual field also should be counted. (3) Divide the repulsive force between an agent and an obstacle into the frontal force and convex corner force. These two forces have different spheres of influence and calculation methods. The agents could exhibit reasonable intelligence and diversity during alighting and boarding
Tsunami evacuation facility choice behavior model in flat area and rias area considering possibility to remain at home
Full text linkThe tsunami associated with the Great East Japan Earthquake that occurred on March 11, 2011 caused enormous damage to the coast of the Pacific Ocean. Since the occurrence of the Great Earthquake, it is urgent to develop tsunami evacuation countermeasures against the great tsunamis caused by the large earthquake that is expected to occur in the future in the country and coastal municipalities. In this study, we used logit model to estimate each parameters about the relationship between evacuees and buildings in flat area and rias area by using the evacuation behavior survey data of the Great East Japan Earthquake in 2011. The estimated results show that “whether the evacuation destination is home or not” is important when people choose the tsunami evacuation destination. Moreover, by comparing the moving in flat area and in rias area the difference between them becomes clear. By using these models, it enables to estimate the home selection probability in flat area and rias area
A Case for Identity Hierarchies in Simulating Social Groups
Full text linkBy considering previous empirical studies in group dynamics, modelling designs for pedestrian simulators and psychological and sociological theories of crowd behaviour, we briefly present a hierarchical, identity-based approach to simulating pedestrian social groups
Application of Ensemble Kalman Filter to Pedestrian Flow
Full text linkWe adopted the Ensemble Kalman Filter (EnKF) methodology in our computational simulation code for pedestrian flows. The EnKF, which is a type of data assimilation methodology, has been developed in the field of weather forecast where the atmospheric condition varies hour by hour. The EnKF estimates the parameters or boundary/initial conditions in the numerical model based on the updated measured data. We considered the EnKF a promising tool for the simulation of pedestrian flows, which are notoriously difficult to predict. In this study, two scenarios were conducted to confirm the usefulness of the EnKF. The first case was unidirectional pedestrian flow in straight corridors, and the second case was Mataf scenario at the Kaaba in Mecca. Needless to say, the second scenario was very challenging because of the number of pilgrims and the degrees of freedom. In each scenario, we conducted the numerical simulation using the original parameter set and then applied the EnKF to improve the accuracy of the simulation
Decentralized Control for Self-driving Cars That can Freely Move on Two-dimensional Plane
Full text linkIn the current traffic rules, cars have to move along lanes and to stop at red traffic lights. However, in the future when all cars become completely driverless, these traffic rules may vanish and cars may be allowed to move freely on two-dimensional plane by avoiding others like pedestrian flow. This innovation could greatly reduce traffic jams. In this study, we propose a decentralized control scheme for future self-driving cars that can freely move on two-dimensional plane, based on the social force model widely used as the model of pedestrian flow. The performance of the proposed scheme is validated via simulation. Although this study is still conceptual and does not consider realistic details, we believe that it paves the way to developing novel traffic systems
Vulnerable People in Microscopic Evacuation Modelling
Full text linkComputational evacuation modelling as a part of approval procedures or design processes is sometimes concerned with vulnerable people requiring special attention. This vulnerability can be based on external circumstances or on individual characteristics. Microscopic methods are well suited to deal with such specific determinants by their ability to model individual movement and certain behavioural aspects. By reference to case studies the possibilities of up-to-date individual evacuation models to cover egress scenarios including vulnerable people are discussed. The selected examples demonstrate that the evacuation of vulnerable people often depends more on the modelling of individual behaviour rather than on a very detailed description of individual characteristics. Group formation and the guidance or assistance of other people will have a strong impact on the evacuation process and thus require special modelling techniques and respective calibration and validation efforts guided by empirical studies
Pedestrian Flow Characteristics at Upstream and Downstream of Bottleneck for Unidirectional Flow under Normal Conditions
Full text linkThe study of pedestrian flow characteristics at upstream and downstream of bottlenecks is important from level of service and evacuation perspective. Many controlled laboratory experiments have been conducted to study pedestrians’ behavior at bottlenecks. However, it is unclear whether experiments can reproduce real crowd flow characteristics. In this paper, real field data was collected at normal conditions for unidirectional pedestrian movement at Mahakaleshwar, a Hindu temple at Ujjain, India during Mahashivaratri, a festival day on which a large number of pilgrims visited the temple. Along the corridor there is a width reduction at a U-turn which creates a bottleneck. It is necessary to study pedestrian flow characteristics at bottlenecks to ensure desired level of service at temple premises during heavy flow. The speed-density relationships of upstream and downstream sections were compared and it was found that flow behavior at both the sections of bottleneck severely differ from each other. Pedestrians in the upstream are either at free flow speed for very low density values or moving slowly for intermediate to high range of density values. From the speed-density relationship, it can be concluded that pedestrians at upstream had visual clues of congestion ahead at bottleneck (pedestrian could also see the downstream flow through barricades). Therefore, pedestrians wait at their position, stay in their comfort zone and do not push each other. Thus, even at intermediate local density, pedestrians have such low speeds. This violates the general assumption that pedestrians change their speed only at the shockwave boundary. The movement of pedestrians at upstream is governed by local density and information of congestion status ahead, whereas pedestrian movement at downstream is governed by factors like density, side friction and pedestrians’ willingness to compensate for the delay at bottleneck. This study is expected to have application in planning and operation of pedestrian facilities
Evacuation Guidance Design: An Experimental Study Based on Eye Tracking Devices
Full text linkIt is a crucial issue whether evacuees follow the evacuation guidance during evacuation. Good evacuation guidance is necessary to be designed to help the evacuees follow the guidance. In this paper, evacuation experiments based on wearable eye tracking devices were carried out to study the design effect of the evacuation guidance. Three factors were considered in these experiments: 1) the position of the evacuation guidance; 2) follow guidance or follow other evacuees; 3) follow a stranger or a familiar person. The results show that more participants noticed the guidance with low position and ground position than the guidance with up position. The evacuees intend to follow others rather than to follow the guidance, i.e. most evacuees act as “follower”. Eye tracking evacuation experiments can also be used to test the effectiveness of evacuation guidance signs
Experimental Study on Variation Strategies for Complex Social Pedestrian Groups in Conflict Conditions
Full text linkThe paper concentrates on an experimental study of the variation strategies of complex social pedestrian groups in conflict conditions. We tracked the trajectories of group members and analysed the configuration of both the complex group and its subgroups when the groups walked through a narrowing passage, passed by an obstacle or faced counter flows. We summarized the variation strategies of complex groups when they faced these conflict conditions. The effect of groups on the crowd was also studied. It was found that groups could have significant effect on self-organization of the crowd. The results in the paper could be applied in modelling pedestrian group decision and behaviour and analysing crowd dynamics
Evacuation characteristics of preschool children through bottlenecks
Full text linkPedestrian movement through bottlenecks have been widely studied from various aspects to understand the effects of bottlenecks on the pedestrian flow. However, few attentions have been paid to the movement characteristics of preschool children, who show obvious differences behaviour compared to adults due to the poor balance and understanding of danger especial under emergencies. In this study, we focus on the evacuation characteristics of preschool children through bottlenecks with laboratory experiments. From all the experiment, we do not observe clear lane formation process from the trajectories diagrams. It is found that the first arrive first out principle does not work in the situation with competition. Compared to adults, children are more likely to fall and hard to be controlled during movement, which is very dangerous in emergencies. The highest speed for the preschool children can beyond 3 m/s and is depend on the location in the crowd for each individual. For a given number of evacuees, the total evacuation time firstly decreases a linear with the increasing the bottleneck width and then keeps a constant if nobody falls down during the movement. Falling down of children will increase the evacuation time incredibly. The findings will be beneficial for the evacuation drill design in kindergarten as well as the facility design for young children