127 research outputs found
Validated force-based modeling of pedestrian dynamics
This dissertation investigates force-based modeling of pedestrian dynamics. Having the quantitative validation of mathematical models in focus principle questions will be addressed throughout this work: Is it manageable to describe pedestrian dynamics solely with the equations of motion derived from the Newtonian dynamics?
On the road to giving answers to this question we investigate the consequences and side-effects of completing a force-based model with additional rules and imposing restrictions on the state variables. Another important issue is the representation of modeled pedestrians. Does the geometrical shape of a two dimensional projection
of the human body matter when modeling pedestrian movement? If yes which form is most suitable? This point is investigated in the second part while introducing a new force-based model. Moreover, we highlight a frequently underestimated aspect in force-based modeling which is to what extent the steering of pedestrians influences their dynamics? In the third part we introduce four possible strategies to define the desired direction of each pedestrian when moving in a facility. Finally, the effects of the aforementioned approaches are discussed by means of
numerical tests in different geometries with one set of model parameters. Furthermore, the validation of the developed model is questioned by comparing simulation results with empirical data
Quantitative Description of Pedestrian Dynamics with a Force based Model
This paper introduces a space-continuous force-based model for simulating
pedestrian dynamics. The main interest of this work is the quantitative
description of pedestrian movement through a bottleneck. Measurements of flow
and density will be presented and compared with empirical data. The results of
the proposed model show a good agreement with empirical data. Furthermore, we
emphasize the importance of volume exclusion in force-based models.Comment: 4 pages, 7 figures, 2009 IEEE/WIC/ACM International Joint Conferences
on Web Intelligence and Intelligent Agent Technologies (WI-IAT 2009), 15-18
September 2009, in Milano, Italy, 200
Influence of the number of predecessors in interaction within acceleration-based flow models
In this paper, the stability of the uniform solutions is analysed for
microscopic flow models in interaction with predecessors. We calculate
general conditions for the linear stability on the ring geometry and explore
the results with particular pedestrian and car-following models based on
relaxation processes. The uniform solutions are stable if the relaxation times
are sufficiently small. The analysis is focused on the relevance of the number
of predecessors in the dynamics. Unexpected non-monotonic relations between
and the stability are presented.Comment: 18 pages, 14 figure
Quantitative Verification of a Force-based Model for Pedestrian Dynamics
This paper introduces a spatially continuous force-based model for simulating
pedestrian dynamics. The main intention of this work is the quantitative
description of pedestrian movement through bottlenecks and in corridors.
Measurements of flow and density at bottlenecks will be presented and compared
with empirical data. Furthermore the fundamental diagram for the movement in a
corridor is reproduced. The results of the proposed model show a good agreement
with empirical data.Comment: 8 pages, 7 figures, Proceedings of Traffic and Granular Flow (TGF)
200
Investigation of Voronoi diagram based Direction Choices Using Uni- and Bi-directional Trajectory Data
In a crowd, individuals make different motion choices such as "moving to
destination", "following another pedestrian", and "making a detour". For the
sake of convenience, the three direction choices are respectively called
destination direction, following direction and detour direction in this paper.
Here, it is found that the featured direction choices could be inspired by the
shape characteristics of Voronoi diagram. To be specific, in the Voronoi cell
of a pedestrian, the direction to a Voronoi node is regarded as a potential
"detour" direction, and the direction perpendicular to a Voronoi link is
regarded as a potential "following" direction. A pedestrian generally owns
several alternative Voronoi nodes and Voronoi links in a Voronoi cell, and the
optimal detour and following direction are determined by considering related
factors such as deviation. Plus the destination direction which is directly
pointing to the destination, the three basic direction choices are defined in a
Voronoi cell. In order to evaluate the Voronoi diagram based basic directions,
the empirical trajectory data in both uni- and bi-directional flow experiments
are extracted. A time series method considering the step frequency is used to
reduce the original trajectories' swaying phenomena which might disturb the
recognition of actual forward direction. The deviations between the empirical
velocity direction and the basic directions are investigated, and each velocity
direction is classified into a basic direction or regarded as an inexplicable
direction according to the deviations. The analysis results show that each
basic direction could be a potential direction choice for a pedestrian. The
combination of the three basic directions could cover most empirical velocity
direction choices in both uni- and bi-directional flow experiments.Comment: 10pages, 12 figure
Quantitative Verification of a Force-based Model for Pedestrian Dynamics
This paper introduces a spatially continuous force-based model for simulating pedestrian dynamics. The main intention of this work is the quantitative description of pedestrian movement through bottlenecks and in corridors. Measurements of flow and density at bottlenecks will be presented and compared with empirical data. Furthermore the fundamental diagram for the movement in a corridor is reproduced. The results of the proposed model show a good agreement with empirical data
Single-file pedestrian dynamics: a review of agent-following models
Single-file dynamics has been studied intensively, both experimentally and
theoretically. It shows interesting collective effects, such as stop-and-go
waves, which are validation cornerstones for any agent-based modeling approach
of traffic systems. Many models have been proposed, e.g. in the form of
car-following models for vehicular traffic. These approaches can be adapted for
pedestrian streams. In this study, we delve deeper into these models, with
particular attention on their interconnections. We do this by scrutinizing the
influence of different parameters, including relaxation times, anticipation
time, and reaction time. Specifically, we analyze the inherent fundamental
problems with force-based models, a classical approach in pedestrian dynamics.
Furthermore, we categorize car-following models into stimulus-response and
optimal velocity models, highlighting their historical and conceptual
differences. These classes can further be subdivided considering the conceptual
definitions of the models, e.g. first-order vs. second-order models, or
stochastic vs. deterministic models with and without noise. Our analysis shows
how car-following models originally developed for vehicular traffic can provide
new insights into pedestrian behavior. The focus on single-file motion, which
is similar to single-lane vehicular traffic, allows for a detailed examination
of the relevant interactions between pedestrians.Comment: 35 pages, 10 Figures; chapter accepted for publication in Crowd
Dynamics (vol. 4
Steady State of Pedestrian Flow in Bottleneck Experiments
Experiments with pedestrians could depend strongly on initial conditions.
Comparisons of the results of such experiments require to distinguish carefully
between transient state and steady state. In this work, a feasible algorithm -
Cumulative Sum Control Chart - is proposed and improved to automatically detect
steady states from density and speed time series of bottleneck experiments. The
threshold of the detection parameter in the algorithm is calibrated using an
autoregressive model. Comparing the detected steady states with previous
manually selected ones, the modified algorithm gives more reproducible results.
For the applications, three groups of bottleneck experiments are analysed and
the steady states are detected. The study about pedestrian flow shows that the
difference between the flows in all states and in steady state mainly depends
on the ratio of pedestrian number to bottleneck width. When the ratio is higher
than a critical value (approximately 115 persons/m), the flow in all states is
almost identical with the flow in steady state. Thus we have more possibilities
to compare the flows from different experiments, especially when the detection
of steady states is difficult.Comment: 19 pages, 7 figure
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