scholarly journals The Inflection Point of the Speed-Density Relation and the Social Force Model

2016 ◽  
Vol 1 ◽  
Author(s):  
Tobias Kretz ◽  
Jochen Lohmiller ◽  
Johannes Schlaich
Keyword(s):  
Inflection Point ◽  
Temporal Variations ◽  
Force Model ◽  
Social Force ◽  
Social Force Model ◽  
Single File ◽  
Stop And Go ◽  
The Social ◽  
Density Relation ◽  
Continuous Description

It has been argued that the speed-density diagram of pedestrian movement has an inflection point. This inflection point was found empirically in investigations of closed-loop single-file pedestrian movement.The reduced complexity of single-file movement does not only allow a higher precision for the evaluation of empirical data, but it also significantly simplifies analytical considerations. This is especially true if one assumes homogeneous conditions, i.e. neglects temporal variations (consider time averages, neglect stop-and-go waves), individual differences of pedestrians (all simulated pedestrians have identical parameters) and investigates only steady-state (not the initial phase). As will be shown in this contribution one then can make a transition from the microscopic to a continuous and macroscopic perspective.Building on that it will be shown that certain (common) variants of the Social Force Model (SFM) do not produce an inflection point in the speed-density diagram if – assuming periodic boundary conditions – infinitely many pedestrians contribute to the force computed for one pedestrian. It will furthermore be shown that if – in said 1d movement situation – one only considers nearest neighbors for the computation of the inter-pedestrian forces the Social Force Model in the continuous description results in the so called Kladek formula for the speed-density relation. Since the Kladek formula exhibits the desired inflection point this observation is used as a motivation for an extension of the Social Force Model which allows to transform the continuous description of the SFM continuously to the Kladek formula and which also exhibits the inflection point in the speed density relation. It will be shown then, that this extended SFM yields astonishingly similar speed density relations as the original SFM when only a fixed limited number of (nearest) pedestrians are considered in the computation of the inter-pedestrian force.Finally it will be discussed, if also the description of the speed-density diagram for (motorized, four-wheel) vehicular and/or bicycle traffic could benefit from these measures.

scholarly journals A Harmony Search Algorithm for the Reproduction of Experimental Data in the Social Force Model

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Osama Moh'd Alia ◽  
Mohammed Mahmod Shuaib
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Harmony Search ◽  
Force Model ◽  
Social Force ◽  
Specific Flow Rate ◽  
Social Force Model ◽  
Specific Flow ◽  
The Social ◽  
Density Relation

Crowd dynamics is a discipline dealing with the management and flow of crowds in congested places and circumstances. Pedestrian congestion is a pressing issue where crowd dynamics models can be applied. The reproduction of experimental data (velocity-density relation and specific flow rate) is a major component for the validation and calibration of such models. In the social force model, researchers have proposed various techniques to adjust essential parameters governing the repulsive social force, which is an effort at reproducing such experimental data. Despite that and various other efforts, the optimal reproduction of the real life data is unachievable. In this paper, a harmony search-based technique called HS-SFM is proposed to overcome the difficulties of the calibration process for SFM, where the fundamental diagram of velocity-density relation and the specific flow rate are reproduced in conformance with the related empirical data. The improvisation process of HS is modified by incorporating the global best particle concept from particle swarm optimization (PSO) to increase the convergence rate and overcome the high computational demands of HS-SFM. Simulation results have shown HS-FSM’s ability to produce near optimal SFM parameter values, which makes it possible for SFM to almost reproduce the related empirical data.

scholarly journals SPECIFICATION OF THE SOCIAL FORCE PEDESTRIAN MODEL BY EVOLUTIONARY ADJUSTMENT TO VIDEO TRACKING DATA

2007 ◽  
Vol 10 (supp02) ◽  
pp. 271-288 ◽  
Author(s):  
ANDERS JOHANSSON ◽  
DIRK HELBING ◽  
PRADYUMN K. SHUKLA
Keyword(s):  
Large Scale ◽  
Optimal Parameter ◽  
Video Tracking ◽  
Urban Environments ◽  
Force Model ◽  
Tracking Data ◽  
Social Force ◽  
Social Force Model ◽  
Video Recordings ◽  
The Social

Based on suitable video recordings of interactive pedestrian motion and improved tracking software, we apply an evolutionary optimization algorithm to determine optimal parameter specifications for the social force model. The calibrated model is then used for large-scale pedestrian simulations of evacuation scenarios, pilgrimage, and urban environments.

scholarly journals Influence of different merging angles of pedestrian flows on evacuation time

Fire Research ◽  
2019 ◽  
Vol 3 (1) ◽  
Author(s):  
Manuela Marques Lalane Nappi ◽  
Ivana Righetto Moser ◽  
João Carlos Souza
Keyword(s):  
Built Environment ◽  
Computer Simulations ◽  
Force Model ◽  
Social Force ◽  
Social Force Model ◽  
Evacuation Time ◽  
Emergency Evacuations ◽  
Crowd Dynamics ◽  
The Social ◽  
The Impact

The growing number of fires and other types of catastrophes occurring at large events highlights the need to rethink safety concepts and also to include new ways to optimize buildings and venues where events are held. Although there have been some attempts to model and simulate the movement of pedestrian crowds, little knowledge has been gathered to better understand the impact of the built environment and its geometric characteristics on the crowd dynamics. This paper presents computer simulations about pedestrians’ crowd dynamics that were conducted based on the Social Force Model. The influence of different configurations of pedestrian flows merging during emergency evacuations was investigated. In this study, 12 designs with different merging angles were examined, simulating the evacuation of 400 people in each scenario. The Planung Transport Verkehr (PTV, German for Planning Transport Traffic) Viswalk module of the PTV Vissim software (PTV Group, Karlsruhe, Germany) program was adopted, which allows the employment of the Social Force approach. The results demonstrate that both symmetric and asymmetric scenarios are sensitive to the angles of convergence between pedestrian flows.

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