Peter Molnar

Starting with a short review of the available literature in the field of pedestrian and evacuation research, an overview is given over the ob- served collective phenomena in pedestrian crowds. This includes lane for- mation in corridors and oscillations at bottlenecks in normal situations, while different kinds of blocked states are produced in panic situations. By means of molecular-dynamic-like microsimulations based on a general- ized force model of interactive pedestrian dynamics, the… Show more

Starting with a short review of the available literature in the field of pedestrian and evacuation research, an overview is given over the ob- served collective phenomena in pedestrian crowds. This includes lane for- mation in corridors and oscillations at bottlenecks in normal situations, while different kinds of blocked states are produced in panic situations. By means of molecular-dynamic-like microsimulations based on a general- ized force model of interactive pedestrian dynamics, the spatio-temporal patterns in pedestrian crowds are successfully reproduced and interpreted as self-organized phenomena. In contrast to previous socio-psychological approaches, this allows a physical understanding of the observations. De- spite the significantly different phenomena occuring in normal and panic situations, the main effects can be described by a unified model containing only well interpretable and plausible terms. The transition between the “ra- tional” normal behavior and the apparently “irrational” panic behavior is controlled by a single parameter, the “nervousness”, which influences fluc- tuation strengths, desired speeds, and the tendency of herding. Thereby, it causes paradoxial effects like “freezing by heating”, “faster is slower”, and the ignorance of available exits. Nevertheless, there are measures to improve pedestrian flows, both in normal and panic situations. For exam- ple, the suitable placement of columns can help, although they reduce the accessible space. Show less

This paper extends our development of acoustical bearings-only target localization for the case of multiple moving targets. The resulting techniques can be used to locate and track targets traveling through a network of acoustical sensor arrays. Each array computes and transmits multiple direction-of-arrival (DOA) estimates to a central processor, which employs the target localization technique. In previous work, we developed ML techniques that may or may not account for the fact that a bearing… Show more

This paper extends our development of acoustical bearings-only target localization for the case of multiple moving targets. The resulting techniques can be used to locate and track targets traveling through a network of acoustical sensor arrays. Each array computes and transmits multiple direction-of-arrival (DOA) estimates to a central processor, which employs the target localization technique. In previous work, we developed ML techniques that may or may not account for the fact that a bearing measurement points to the location of a moving target at a retarded time. By inserting a simple bearings association computation in the ML methods, we define quasi-ML techniques that can estimate the location and velocity of multiple targets using multiple bearing estimates per a sensor array. Show less

Self-organized and error-resistant control of distributed autonomous robotic units in a manufacturing environment with obstacles where the robotic units have to be assigned to manufacturing targets in a cost effective way, is achieved by using two fundamental principles of nature. First, the selection behavior of modes is used which appears in pattern formation of physical, chemical and biological systems. Coupled selection equations based on these pattern formation principles can be used as… Show more

Self-organized and error-resistant control of distributed autonomous robotic units in a manufacturing environment with obstacles where the robotic units have to be assigned to manufacturing targets in a cost effective way, is achieved by using two fundamental principles of nature. First, the selection behavior of modes is used which appears in pattern formation of physical, chemical and biological systems. Coupled selection equations based on these pattern formation principles can be used as dynamical system approach to assignment problems. These differential equations guarantee feasibility of the obtained solutions which is of great importance in industrial applications. Second, a model of behavioral forces is used, which has been successfully applied to describe self-organized crowd behavior of pedestrians. This novel approach includes collision avoidance as well as error resistivity. In particular, in systems where failures are of concern, the suggested approach outperforms conventional methods in covering up for sudden external changes like breakdowns of some robotic units. The capability of this system is demonstrated in computer simulations Show less

Although pedestrians have individual preferences, aims, and destinations, the dynamics of pedestrian crowds is surprisingly predictable. Pedestrians can move freely only at small pedestrian densities. Otherwise their motion is affected by repulsive interactions with other pedestrians, giving rise to self-organization phenomena. Examples of the resulting patterns of motion are separate lanes of uniform walking direction in crowds of oppositely moving pedestrians or oscillations of the passing… Show more

Although pedestrians have individual preferences, aims, and destinations, the dynamics of pedestrian crowds is surprisingly predictable. Pedestrians can move freely only at small pedestrian densities. Otherwise their motion is affected by repulsive interactions with other pedestrians, giving rise to self-organization phenomena. Examples of the resulting patterns of motion are separate lanes of uniform walking direction in crowds of oppositely moving pedestrians or oscillations of the passing direction at bottlenecks. If pedestrians leave footprints on deformable ground (for example, in green spaces such as public parks) this additionally causes attractive interactions which are mediated by modifications of their environment. In such cases, systems of pedestrian trails will evolve over time. The corresponding computer simulations are a valuable tool for developing optimized pedestrian facilities and way systems. Show less

The task of assigning a team of mobile robotic systems to individual job-locations has many challenges. We use the dynamical systems approach of coupled selection equations to achieve this problem. This intrinsically distributed algorithm has several advantages over traditional integer programs and other distributed approaches: 1) no backtracking is needed, 2) it can be used for NP-hard problems, such as assigning multiple robots with different capabilities to a certain job (three- or… Show more

The task of assigning a team of mobile robotic systems to individual job-locations has many challenges. We use the dynamical systems approach of coupled selection equations to achieve this problem. This intrinsically distributed algorithm has several advantages over traditional integer programs and other distributed approaches: 1) no backtracking is needed, 2) it can be used for NP-hard problems, such as assigning multiple robots with different capabilities to a certain job (three- or higher-index assignment problems), and 3) feasibility of the obtained solutions can be guaranteed.
The key point of the applicability in real distributed environments is a distinctive communication fault tolerance so that the necessary data communication between the different processes does not alter to an Achilles heel of the system. Therefore, the present paper addresses the loss of messages in a distributed robotic system based on coupled selection equations, and demonstrates the remarkable communication fault tolerance of this specific dynamical system approach by computer simulations. Show less

Pedestrian crowds can very realistically be simulated with a social force model
which describes the different influences affecting individual pedestrian motion by a few
simple force terms. The model is able to reproduce the emergence of several empirically
observed collective patterns of motion. These self-organization phenomena can be utilized
for new flow optimization methods which are indispensable for skilful town-and traffic-
planning.

Active walker models have recently proved their great value for describing the formation of clusters, periodic patterns, and spiral waves as well as the devel- opment of rivers, dielectric breakdown patterns, and many other structures. It is shown that they also allow to simulate the formation of trail systems by pedestrians and ants, yielding a better understanding of human and ani- mal behavior. A comparison with empirical material shows a good agreement between model and reality.
Our… Show more

Active walker models have recently proved their great value for describing the formation of clusters, periodic patterns, and spiral waves as well as the devel- opment of rivers, dielectric breakdown patterns, and many other structures. It is shown that they also allow to simulate the formation of trail systems by pedestrians and ants, yielding a better understanding of human and ani- mal behavior. A comparison with empirical material shows a good agreement between model and reality.
Our trail formation model includes an equation of motion, an equation for environmental changes, and an orientation relation. It contains some model functions, which are specified according to the characteristics of the considered animals or pedestrians. Not only the kind of environmental changes differs: Whereas pedestrians leave footprints on the ground, ants produce chemical markings for their orientation. Nevertheless, it is more important that pedes- trians steer towards a certain destination, while ants usually find their food sources by chance, i.e. they reach their destination in a stochastic way. As a consequence, the typical structure of the evolving trail systems depends on the respective species. Some ant species produce a dendritic trail system, whereas pedestrians generate a minimal detour system.
The trail formation model can be used as a tool for the optimization of pedestrian facilities: It allows urban planners to design convenient way systems which actually meet the route choice habits of pedestrians. Show less

Many human social phenomena, such as cooperation, the growth of settlements, traffic dynamics and pedestrian movement, appear to be accessible to mathematical descriptions that invoke self-organization. Here we develop a model of pedestrian motion to explore the evolution of trails in urban green spaces such as parks. Our aim is to address such questions as what the topological structures of these trail systems are, and whether optimal path systems can be predicted for urban planning. We use an… Show more

Many human social phenomena, such as cooperation, the growth of settlements, traffic dynamics and pedestrian movement, appear to be accessible to mathematical descriptions that invoke self-organization. Here we develop a model of pedestrian motion to explore the evolution of trails in urban green spaces such as parks. Our aim is to address such questions as what the topological structures of these trail systems are, and whether optimal path systems can be predicted for urban planning. We use an 'active walker' model that takes into account pedestrian motion and orientation and the concomitant feedbacks with the surrounding environment. Such models have previously been applied to the study of complex structure formation in physical, chemical and biological systems. We find that our model is able to reproduce many of the observed large-scale spatial features of trail systems. Show less

It is suggested that the motion of pedestrians can be described as if they would be subject to ‘‘social forces.’’ These ‘‘forces’’ are not directly exerted by the pedestrians’ personal environment, but they are a measure for the internal motivations of the individuals to perform certain actions (movements). The corresponding force concept is discussed in more detail and can also be applied to the description of other behaviors. In the presented model of pedestrian behavior several force terms… Show more

It is suggested that the motion of pedestrians can be described as if they would be subject to ‘‘social forces.’’ These ‘‘forces’’ are not directly exerted by the pedestrians’ personal environment, but they are a measure for the internal motivations of the individuals to perform certain actions (movements). The corresponding force concept is discussed in more detail and can also be applied to the description of other behaviors. In the presented model of pedestrian behavior several force terms are essential: first, a term describing the acceleration towards the desired velocity of motion; second, terms reflecting that a pedestrian keeps a certain distance from other pedestrians and borders; and third, a term modeling attractive effects. The resulting equations of motion of nonlinearly coupled Langevin equations. Computer simulations of crowds of interacting pedestrians show that the social force model is capable of describing the self-organization of several observed collective effects of pedestrian behavior very realistically. Show less

A simulation model for the dynamic behaviour of pedestrian crowds is mathematically formulated in terms of a social force model, that means, pedestrians behave in a way as if they would be subject to an acceleration force and to repulsive forces describing the reaction to borders and other pedestrians. The computational simulations presented yield many realistic results that can be compared with video films of pedestrian crowds. Especially, they show the self-organization of collective… Show more

A simulation model for the dynamic behaviour of pedestrian crowds is mathematically formulated in terms of a social force model, that means, pedestrians behave in a way as if they would be subject to an acceleration force and to repulsive forces describing the reaction to borders and other pedestrians. The computational simulations presented yield many realistic results that can be compared with video films of pedestrian crowds. Especially, they show the self-organization of collective behavioural patterns.
By assuming that pedestrians tend to choose routes that are frequently taken the above model can be extended to an active walker model of trail formation. The topological structure of the evolving trail network will depend on the disadvantage of building new trails and the durability of existing trails. Computer simulations of trail formation indicate to be a valuable tool for designing systems of ways which satisfy the needs of pedestrians best. An example is given for a non-directed trail network. Show less