A glossary for research on human crowd dynamics

This article presents a glossary of terms that are frequently used in research on human crowds. This topic is inherently multidisciplinary as it includes work in and across computer science, engineering, mathematics, physics, psychology and social science, for example. We do not view the glossary presented here as a collection of finalised and formal definitions. Instead, we suggest it is a snapshot of current views and the starting point of an ongoing process that we hope will be useful in providing some guidance on the use of terminology to develop a mutual understanding across disciplines. The glossary was developed collaboratively during a multidisciplinary meeting. We deliberately allow several definitions of terms, to reflect the confluence of disciplines in the field. This also reflects the fact not all contributors necessarily agree with all definitions in this glossary

Dynamics and thermodynamics of a gas automata

We consider a system of point charges interacting within a cone of vision and confined by an external potential, as a simple model of individuals provided with vision. The non Newtonian nature of the interaction introduces dissipative effects which are balanced by a memory mechanism. The two-body system is amenable to quadrature, whereas the $N \gg 1$ body system exhibits crystal-like and disordered states with a non-trivial phase diagram if the interaction range and memory persistence are chosen as control parameters

Social force model with explicit collision prediction

We introduce a new specification of the social force model in which pedestrians explicitly predict the place and time of the next collision in order to avoid it. This and other specifications of the social force model are calibrated, using genetic algorithms, on a set of pedestrian trajectories, obtained tracking with laser range finders the movement of pedestrians in controlled experiments, and their performance is compared. The results show that the proposed method has a better performance in describing the trajectory set

A mesoscopic model for the effect of density on pedestrian group dynamics

We introduce a mesoscopic model of pedestrian group behaviour, in which the internal group dynamics is modelled using a microscopic potential, while the effect of the environment is modelled using a harmonic term whose intensity depends on a macroscopic quantity, crowd density. We show that, in order to properly describe the behaviour of 2-person groups, the harmonic term is directed orthogonally to the walking direction, and its intensity grows linearly with density. We also show that, once calibrated on 2-person groups, the model correctly predicts the velocity and spatial extension of 3-person groups in the walking direction, while in order to describe properly also the abreast extension of 3-person groups a modification in the microscopic group dynamics has to be introduced. The model also correctly predicts the presence of a bifurcation phenomenon, namely the emergence of a stable 3-person Λ configuration at high densities, while only the V formation is stable at low densities

Error distribution in randomly perturbed orbits

E' stata condotta una analisi di sistemi dinamici discreti 1D e 2D perturbati stocasticamente, utilizzando la fidelity per valutare la evoluzione nel tempo della distribuzione degli errori. Ci\uf2 che distingue le propriet\ue0 dinamiche delle mappe \ue8 la modalit\ue0 di rilassamento verso la distribuzione asintotica di equilibrio, che \ue8 superesponenziale per mappe caotiche, eponenziale per mappe regolari. Nelle prime esiste una soglia temporale netta, che cresce come il logaritmo dell'inverso della ampiezza del rumore, al di sotto del quale l'effetto della perturbazione \ue8 trascurabil