13,434 research outputs found
Pedestrian Flow Simulation Validation and Verification Techniques
For the verification and validation of microscopic simulation models of
pedestrian flow, we have performed experiments for different kind of facilities
and sites where most conflicts and congestion happens e.g. corridors, narrow
passages, and crosswalks. The validity of the model should compare the
experimental conditions and simulation results with video recording carried out
in the same condition like in real life e.g. pedestrian flux and density
distributions. The strategy in this technique is to achieve a certain amount of
accuracy required in the simulation model. This method is good at detecting the
critical points in the pedestrians walking areas. For the calibration of
suitable models we use the results obtained from analyzing the video recordings
in Hajj 2009 and these results can be used to check the design sections of
pedestrian facilities and exits. As practical examples, we present the
simulation of pilgrim streams on the Jamarat bridge.
The objectives of this study are twofold: first, to show through verification
and validation that simulation tools can be used to reproduce realistic
scenarios, and second, gather data for accurate predictions for designers and
decision makers.Comment: 19 pages, 10 figure
Quantitative validation of PEDFLOW for description of unidirectional pedestrian dynamics
The results of a systematic quantitative validation of PEDFLOW based on the
experimental data from FZJ are presented. Unidirectional flow experiments,
totaling 28 different combinations with varying entry, corridor and exit
widths, were considered. The condition imposed on PEDFLOW was that all the
cases should be run with the same input parameters. The exit times and
fundamental diagrams for the measuring region were evaluated and compared. This
validation process led to modifications and enhancements of the model
underlying PEDFLOW. The preliminary conclusions indicate that the results agree
well for densities smaller than 3 m-2 and a good agreement is observed even at
high densities for the corridors with bcor = 2.4 m, and bcor = 3.0 m. For
densities between 1 and 2 m-2 the specific flow and velocities are
underpredicted by PEDFLOW.Comment: 6 pages, 3 figures, 1 Table, conference PED201
Modeling Crowd Turbulence by Many-Particle Simulations
A recent study [D. Helbing, A. Johansson and H. Z. Al-Abideen, {\it Phys.
Rev. E} 75, 046109 (2007)] has revealed a "turbulent" state of pedestrian
flows, which is characterized by sudden displacements and causes the falling
and trampling of people. However, turbulent crowd motion is not reproduced well
by current many-particle models due to their insufficient representation of the
local interactions in areas of extreme densities. In this contribution, we
extend the repulsive force term of the social force model to reproduce crowd
turbulence. We perform numerical simulations of pedestrians moving through a
bottleneck area with this new model. The transitions from laminar to
stop-and-go and turbulent flows are observed. The empirical features
characterizing crowd turbulence, such as the structure function and the
probability density function of velocity increments are reproduced well, i.e.
they are well compatible with an analysis of video data during the annual
Muslim pilgrimage
Effects of communication efficiency and exit capacity on fundamental diagrams for pedestrian motion in an obscure tunnel|a particle system approach
Fundamental diagrams describing the relation between pedestrians speed
and density are key points in understanding pedestrian dynamics.
Experimental data evidence the onset of complex behaviors in which the
velocity decreases with the density and different logistic regimes are
identified. This paper addresses the issue of pedestrians transport and of fundamental diagrams for a scenario involving the motion of pedestrians
escaping from an obscure tunnel.
% via a simple one--dimensional particle system model.
We capture the effects of the communication efficiency and
the exit capacity by means of two thresholds controlling the rate
at which particles (walkers, pedestrians) move on the lattice.
Using a particle system model, we show that in absence of limitation in communication among
pedestrians we reproduce
with good accuracy the standard fundamental diagrams, whose
basic behaviors can be interpreted in terms of the exit capacity
limitation.
When the effect of a limited communication ability is considered, then
interesting non--intuitive phenomena occur. Particularly, we shed light on
the loss of monotonicity of the typical speed--density curves,
revealing the existence of a
pedestrians density optimizing the escape.
We study both the discrete particle dynamics as well as the corresponding hydrodynamic limit (a porous medium equation and a transport (continuity) equation). We also point out the dependence of the effective transport coefficients on the two thresholds -- the essence of the microstructure information
Analyzing Stop-and-Go Waves by Experiment and Modeling
The main topic of this paper is the analysis and modeling of stop-and-go
waves, observable in experiments of single lane movement with pedestrians. The
velocity density relation using measurements on a 'microscopic' scale shows the
coexistence of two phases at one density. These data are used to calibrate and
verify a spatially continuous model. Several criteria are chosen that a model
has to satisfy: firstly we investigated the fundamental diagram (velocity
versus density) using different measurement methods. Furthermore the
trajectories are compared to the occurrence of stop-and-go waves qualitatively.
Finally we checked the distribution of the velocities at fixed density against
the experimental one. The adaptive velocity model introduced satisfies these
criteria well.Comment: Fifth International Conference on Pedestrian and Evacuation Dynamics,
March 8-10, 2010, National Institute of Standards and Technology,
Gaithersburg, MD US
Pedestrian dynamics in single-file movement of crowd with different age compositions
An aging population is bringing new challenges to the management of escape
routes and facility design in many countries. This paper investigates
pedestrian movement properties of crowd with different age compositions. Three
pedestrian groups are considered: young student group, old people group and
mixed group. It is found that traffic jams occur more frequently in mixed group
due to the great differences of mobilities and self-adaptive abilities among
pedestrians. The jams propagate backward with a velocity 0.4 m/s for global
density around 1.75 m-1 and 0.3 m/s for higher than 2.3 m-1. The fundamental
diagrams of the three groups are obviously different from each other and cannot
be unified into one diagram by direct non-dimensionalization. Unlike previous
studies, three linear regimes in mixed group but only two regimes in young
student group are observed in the headway-velocity relation, which is also
verified in the fundamental diagram. Different ages and mobilities of
pedestrians in a crowd cause the heterogeneity of system and influence the
properties of pedestrian dynamics significantly. It indicates that the density
is not the only factor leading to jams in pedestrian traffic. The composition
of crowd has to be considered in understanding pedestrian dynamics and facility
design.Comment: 11 pages, 13 figures, 3 table
- …