Now it's getting technical! Simulations model reality, i.e. they reduce or extract reality to its characteristic properties in order to make complex processes tangible and calculable. For this purpose, typical patterns are usually identified via research (e.g. Jülich) and transferred into models that can be mapped by the computer.
In the field of pedestrian simulation, two aspects are particularly important: How do I move in space and when do I move, i.e. spatial and temporal decisions. Here we distinguish between a discrete up to a quasi-continuous mapping:
Why quasi-continuous? Since each computer can calculate only discretely (each calculation is executed in the clock of the processor) a temporal discretization takes place inevitably for each computer program of the world. The same is true for the spatial discretization: The continuity existing in reality can only be approximated by the computers.
However, the degree of resolution varies. While some models resolve the geometry cell-based to agent size, i.e. are still quite coarse, there are other models (such as crowd:it) whose standard resolution is quasi-continuous by interpolating support points 10cm away. The setting of the grid points can be adjusted individually and increased simply by clicking.
For the mapping of the temporal decision there are also different accuracies. Either the model assigns all agents a fixed time in which each is allowed to take a step (usually several times per second) or an agent can decide to leave at any time. The former case is implemented in models based on differential equations. These equations are then re-evaluated at each time point (e.g., social force models). We have now changed this decision from synchronized time steps to individual time steps. Because this is how reality works: people decide when to take a step without a globally ticking clock. In this way, we manage to represent human behavior even better and to get more reality into the simulation. Our software can transfer another aspect from reality into the model world.
Selected publications on the simulation model
(1)M. J. Seitz and G. Köster, Natural discretization of pedestrian movement in continuous space, American Physical Society, PHYSICAL REVIEW E 2012, 86, 046108
(2)Kneidl, A.; Hartmann, D.; Borrmann, A. (2013): A hybrid multi-scale approach for simulation of pedestrian dynamics. In: Transportation Research Part C, in press.
(3)Kneidl, A. (2013). Methoden zur Abbildung menschlichen Navigationsverhaltens bei der Modellierung von Fußgängerströmen, PhD Thesis, Technische Universität München
(4)I. v. Sivers, G. Köster (2014): How stride adaption in pedestrian models improves navigation
(5)G. Köster, F. Treml, M. Seitz & W. Klein (2014) Validation of Crowd Models Including Social Groups, in Pedestrian and Evacuation Dynamics 2012, Springer.
(6)Angelika Kneidl (2015): How Do People Queue - A Study Of Different Queuing Models, TGF '15, Delft, Netherlands.
(8)G. Köster, D. Lehmberg, F. Dietrich: „Is Slowing Down Enough To Model Movement On Stairs?“, TGF '15, Delft, Netherlands.
(10) G. Köster; D. Lehmberg; A. Kneidl(2019): Walking on stairs: Experiment and model. In: Physical Review E, Vol. 100, Iss. 2 — August 2019.
Literature studies on setting parameters for the simulation model
(11)Richtlinie für Mikroskopische Entfluchtungsanalysen, Version 3.0, 10. März 2016,
(12)Weidmann, U. (1993): Transporttechnik der Fussgänger: Transporttechnische Eigenschaften des Fussgängerverkehrs (Literaturauswertung)
(13)Forell, B., Klüpfel H., Schneider, V., Schelter S. (2011) Vergleichende Betrachtung zu Evakuierungsberechnungen
(14)Schneider, B., Seyfried, A.: Methods for measuring pedestrian density, flow, speed and direction with minimal scatter, Physica A, vol. 389, no. 9, pp. 1902–1910, 2010.
(15)Oberhagemann, D.: Statische und dynamische Personendichten bei Großveranstaltungen, vfdb Technischer Bericht, März 2012
(16)Lam, Yuen et al. 2014 - Experimental study on upward movement in a high-rise building, Safety Science 70:397–405
(17) Leitfaden Ingenieurmethoden des Brandschutzes, Technischer Bericht vfdb TB 04-01, 3. Auflage November 2013, Hrsg.: Vereinigung zur Förderung des Deutschen Brandschutzes e. V. (vfdb), Technisch-Wissenschaftlicher Beirat (TWB), Referat 4, Prof. Dietmar Hosser