Collective Dynamics (E-Journal)
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A Memory-Based Evacuation Navigation Model in Complex High-Rise Buildings
Full text linkIn contemporary society, safety issues are the main focus in the field of pedestrian and evacuation dynamics. As for complex high-rise buildings, the navigation strategies of evacuees still need to be further studied. Previous types of research has contributed to the construction of evacuation navigation model in complex high-rise buildings, where pedestrians are regarded as having an omniscient view in most of these models. In reality, evacuees’ perception is always limited, especially when the scenario is complex. In this contribution, pedestrians’ perception procedure is considered by computing the visible space so that the occlusion of the visual field can be estimated. In addition, human memory progress is modeled. Not all parts of environmental information would be remembered. Driven by evacuees’ memory data, a proposed dynamical shortest path algorithm will be periodically implemented or suddenly triggered by incidents during the simulation. For the pedestrians who have no enough knowledge about the evacuation scenario, a communication system is utilized so that information can be obtained from well-knowledged pedestrian, and an autonomous way-finding system will be executed when useful information cannot be acquired through near evacuees. For the microscopic perspective, human following and avoidance behavior is modeled. Simulations in two different types of scenarios are conducted. The knowledge level of simulated agents is gradually evolved by in-room free exploration. Results in different conditions show that the proposed memory-based model can reproduce pedestrians’ observation, turn-back, communication, and searching behavior. The intense conflict caused by the bidirectional crowd is observed and analyzed. In addition, the effects of knowledge level are investigated. The presented model in this contribution can be promising and useful in safety engineering
RSSi-Based Visitor Tracking in Museums via Cascaded AI Classifiers and Coloured Graph Representations
Full text linkIndividual tracking of museum visitors based on portable radio beacons, an asset for behavioural analyses and comfort/performance improvements, is seeing increasing diffusion. Conceptually, this approach enables room-level localisation based on a network of small antennas (thus, without invasive modification of the existent structures). The antennas measure the intensity (RSSi) of self-advertising signals broadcasted by beacons individually assigned to the visitors. The signal intensity provides a proxy for the distance to the antennas and thus indicative positioning. However, RSSi signals are well-known to be noisy, even in ideal conditions (high antenna density, absence of obstacles, absence of crowd, ...). In this contribution, we present a method to perform accurate RSSi-based visitor tracking when the density of antennas is relatively low, e.g. due to technical constraints imposed by historic buildings. We combine an ensemble of "simple" localisers, trained based on ground-truth, with an encoding of the museum topology in terms of a total-coloured graph. This turns the localisation problem into a cascade process, from large to small scales, in space and in time. Our use case is visitors tracking in Galleria Borghese, Rome (Italy), for which our method manages >96% localisation accuracy, significantly improving on our previous work (J. Comput. Sci. 101357, 2021)
Exploring the Gait and Stability of Passengers at the Moment they get off an Urban Railway Train by Laboratory Experiments
Full text linkThe Santiago of Chile subway system is nowadays one of the most used means of transportation in the city, therefore many passengers with reduced mobility prefer it. However, in the subway lines, we can find different vertical gaps that are generated between the train and the platform. These vertical gaps makes it difficult for passengers with reduced mobility to get on and off the train, by generating a change in their gait, affecting their stability. This stability can be represented by different variables such as the rejection and damping force, the travel ranges of each step component, and the area generated by these travel ranges. The objective of this paper is to study, experimentally, the effect of vertical gaps on the gait and stability of passengers with reduced mobility in the train-platform space of subway stations. For this purpose, the construction of full-scale experiments representing the train-platform transition was carried out at the Human Dynamics Laboratory of the Universidad de los Andes. To obtain the data, a Bertec force plate and Bertec Acquire 4 software were used, which allows, to obtain the force in the z-axis and the pressure centers in the x-axis and y-axis. The results show that the higher the vertical gap, the higher the instability in passengers with reduced mobility. In addition, it was also observed how passengers with reduced mobility change their gait strategy when having to face vertical gaps greater than 11 cm, since they changed the angle of inclination with which people position their foot when descending, to be able to do the process with greater stability. It is hoped that future experiments will expand the scope of this type of study, by implementing more instrumentation and a larger number of participants
A Comparative Study of Flows Through Funnel-Shaped Bottlenecks Placed in the Middle and Corner
Full text linkUpon exiting buildings, theatres, and stadiums, which house a great number of people, egress points can act as bottlenecks, resulting in crowded exits and decreased flows. Most studies investigating flow have been conducted in either narrow bottlenecks (doors) or funnel shape bottlenecks, with the latter investigating bottlenecks placed in the middle of the walkway. This study investigates, for the first time, crowd flow through funnel-shaped bottlenecks placed in the corner of the walkway and makes comparisons with similar bottlenecks of the same length, entrance and exit width placed in the middle of the walkway. The entry width and exit width of the bottlenecks were 3 m and 1 m respectively, with lengths varying from 1 m to 4 m; they continued into a 10 m corridor. Ninety-four participants of various ages were observed moving through each of the configurations. The results indicated that using funnel-shaped bottlenecks in the middle of the walkway increased the flow rate significantly compared to the corner in bottlenecks with 2 m and 3 m lengths. This is contrary to what some other researchers have found for narrow bottlenecks placed in the middle and corner of a wall, although it is recognised that the configuration of funnel-shaped bottlenecks makes the comparison more complex and further work is required in this area. Notwithstanding these results are considered valuable for consideration when designing egress points and corridors in complex buildings such as metro and train stations
Effect of a Moving Obstacle on Pedestrian Flow Through an Exit
No full textCurrent studies about moving obstacles mainly focus on uncommon evacuation scenarios, while there lacks researches on common egress scenarios, such as evacuation from an exit. This study aims to prove that pedestrian flow through exit can be improved by the presence of a moving obstacle and investigate the effect of a moving obstacle on regulating pedestrian flow. Unidirectional pedestrian flow simulations based on social force model are conducted to study the influence of a moving obstacle, that is a mobile robot, on the pedestrian flow through an exit. The robot reciprocates parallel to the wall of the exit with a constant speed 0.5m/s, and the gap between the robot and the exit is set to 1.0m. The pedestrians need to obey the rule of avoiding collision with the robot. By comparing the distributions of individual evacuation time with and without a moving obstacle, it is proven that that the average evacuation time can be reduced by a moving obstacle obviously. The moving obstacle can lead to the inhomogeneous distribution of the crowd near the exit by observing the density profiles. Furthermore, the crowd near the exit is classified into four groups according to movement direction (left or right) and position (the left or right part relative to the center of the exit) of the robot. It reveals that the moving obstacle impedes the evacuation of small proportion pedestrians, but promotes the evacuation of the large proportion pedestrians by the analysis on the fundamental diagrams of the four groups
Moving Risk of Crowds in the Entrance Confluence Area in the Presence of Channelizing Facilities
Full text linkIn recent years, the measures to interfere the crowds movement with physical facilities (such as channelizing, separation railing) have become more and more common, but how they affect the crowd movement and what moving risks exist in the entrance confluence area have not been fully revealed. Therefore, this paper analyzes the moving risk of the crowds before the bottleneck entrance area, in the presence of the channelizing barriers by controllable laboratory experiments. The visual color cloud charts of the local density, speed and confusion degree of moving directions within the entrance confluence area are analyzed in the presence of different gaps (1.05m and 0.7m) channelizing barriers, to further quantify the motion risk of the crowds. The study finds that the narrower gaps of the channelizing railings, the larger area of high-risk zones, and they have clear ‘lane formation’ effect in shaping the risk zones. The both ends of the channelizing barriers are higher moving risk zones for multi-entry sides conditions, but the area before the middle channels also needs to be closely concerned when the participants entering from two opposite entering sides. The study will provide theoretical basis for evaluating the safety of the setting conditions of the channelizing barriers and conducting scientific crowd management decisions
Microscopic Characteristics and Modelling of Pedestrian Inflow Process with Inactive Persons
Full text linkInflow and outflow processes are common phenomena in daily life. Many types of research have been conducted to study the features of the outflow process, especially in scenarios with a single room or a straight corridor. A few scholars have paid attention to the movement characteristics of pedestrian inflow. Further explorations are still under great demand. In this contribution, a set of pre-conducted experiments are used to analyze the characteristics of the pedestrian inflow process with inactive persons. In these experiments, inactive persons were required to randomly cease within the room, leading to intensive detour behavior of pedestrians. The characteristics are carefully investigated using gradient analysis and curl analysis. To mimic the aforementioned inflow process, static global field is constructed to heuristically navigate a social force based microscopic model. The proposed model can reproduce the self-organized phenomena in the experiments. Our work can help understand the field feature of the pedestrian inflow process with inactive persons. High chaos level areas can be marked out providing practical information for managers
Initiating Lane and Band Formation in Heterogeneous Pedestrian Dynamics
Full text linkSelf-avoiding agents such as pedestrians or road vehicles can exhibit different types of collective and coordinated dynamics. Prominent examples are stop-and-go waves and lane formation, or nonuniform patterns and ordered structures at bottlenecks and intersections. Non-linear effects, phase transitions, and metastability in the collective dynamics of interacting agents raise interesting theoretical questions. Besides scientific interests, understanding and controlling collective performances from individual interaction rules is fundamental to authorities. In this contribution, we show using a two-species agent-based model that heterogeneity can generically initiate segregation and spontaneous formation of lanes and bands. Two universal heterogeneity mechanisms are identified. In the first one, we attribute statically two different values to the parameters of the two types of agents. We aim here to model static heterogeneous individual characteristics. In the second model, we attribute dynamically two different values for the parameters according to the type of the closest agent in front. In contrast to the first model for which the heterogeneity lies statically in agent characteristics, we aim to model dynamic heterogeneity in the interactions. Simulation results show that self-organized lane and band formations spontaneously occur when the heterogeneity factors are sufficiently high. More precisely, we observe the emergence of longitudinal lanes when the heterogeneity lies in the agents when transversal bands arise if we assume heterogeneity in the interactions. The different organizations of the flow highly influence the system's performance. Lane patterns significantly improve the flow, while band formation acting as gridlocks result in lower performance
Modeling Routing Choices in Unidirectional Pedestrian Flows
Full text linkIn this work we present a simple routing model capable of capturing pedestrians path choices in the presence of a herding effect. The model is tested and validated against data from a large scale tracking campaign which we have conducted during the GLOW 2019 festival. The choice between alternative paths is modeled as an individual cost minimization procedure, with the cost function being associated to the (estimated) traveling time. In order to trigger herding effects the cost function is supplemented with a penalty term, modulated as a function of the fraction of pedestrians walking along each route. The model is shown to provide an accurate quantitative description of the decision process
The Influence of Fixed and Moving NPC on Pedestrians’ Avoidance Behaviors: VR-Based Experiments
Full text linkPedestrians have to take actions when crossing other pedestrians to avoid collisions. In this work, we focus on the differences of avoidance behaviors when a pedestrian crosses a moving and fixed intruder (NPC) in the virtual environment. The avoidance process is divided into three stages using the start avoidance point and maximum lateral deviation point. In moving NPC experiments, the distance from start avoidance point to the potential collision point (CP) first decreases and then increases as the intrusion angle increases. In standing NPC experiments, pedestrians start avoidance closer to the CP (average distance: 3.73m). In moving NPC experiments, the average maximum lateral offset distance (MLD) for the pedestrians to detour decreases with the intrusion angles decreases (Behind MLD ∈[1.09 m, 1.94 m], Front MLD ∈[1.13 m, 1.56 m]). In standing NPC experiments, the average MLD is 1.01m (left: 1.04m, right: 0.98m), which is the closest to the MLD of pedestrians at 180° intrusion angles. What’s more, at 30°, 60°, 90° and 120° intrusion angles, pedestrians avoiding behind the NPC require higher MLD than others avoiding in front of the NPC. Thus, more subjects prefer to avoid in front of the NPC under these conditions (88%, 86%, 78%, 69% of all). But the preference weakens and disappears at 150° and 180° intrusion angles due to the decrease of MLD. In standing NPC experiments, significant left-right preference is not found in pedestrians’ avoidance strategies (right: 46%, left: 54%). This article quantitatively analyses the difference between the influence of fixed and movement NPC on pedestrians’ avoidance strategies. The mechanism of pedestrian’s avoidance behavior is obtained by analyzing characteristic parameters, which is helpful to adjust pedestrian avoidance prediction models and design humanoid robots