scholarly journals The visual coupling between neighbors explains 'flocking' in human crowds

2021 ◽  
Author(s):  
Gregory C. Dachner ◽  
Trenton D. Wirth ◽  
Emily Richmond ◽  
William H Warren
Keyword(s):  
Angular Velocity ◽  
Walking Speed ◽  
Collective Motion ◽  
Natural Consequence ◽  
Local Interactions ◽  
Physical Systems ◽  
Fish Schools ◽  
Visual Model ◽  
Visual Occlusion ◽  
Overhead View

Patterns of collective motion or 'flocking' in birds, fish schools, and human crowds are believed to emerge from local interactions between individuals. Most models of collective motion attribute these interactions to hypothetical rules or forces, often inspired by physical systems, and described from an overhead view. We develop a visual model of human flocking from an embedded view, based on optical variables that actually govern pedestrian interactions. Specifically, people control their walking speed and direction by canceling the average optical expansion and angular velocity of their neighbors, weighted by visual occlusion. We test the model by simulating data from experiments with virtual crowds and real human 'swarms'. The visual model outperforms our previous overhead model and explains basic properties of physics-inspired models: 'repulsion' forces reduce to canceling optical expansion, 'attraction' forces to canceling optical contraction, and 'alignment' to canceling the combination of expansion/contraction and angular velocity. Critically, the neighborhood of interaction follows from Euclid's Law of perspective and the geometry of occlusion. We conclude that the local interactions underlying human flocking are a natural consequence of the laws of optics. Similar principles may apply to collective motion in other species.

scholarly journals Collective Motion in Human Crowds

2018 ◽  
Vol 27 (4) ◽  
pp. 232-240 ◽  
Author(s):  
William H. Warren
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
Local Level ◽  
Self Organization ◽  
Coherent Motion ◽  
Global Level ◽  
Crowd Behavior ◽  
Local Interactions ◽  
Fish Schools ◽  
Emergency Situations

The balletic motion of bird flocks, fish schools, and human crowds is believed to emerge from local interactions between individuals in a process of self-organization. The key to explaining such collective behavior thus lies in understanding these local interactions. After decades of theoretical modeling, experiments using virtual crowds and analysis of real crowd data are enabling us to decipher the “rules of engagement” governing these interactions. On the basis of such results, my students and I built a dynamical model of how a pedestrian aligns his or her motion with that of a neighbor and how these binary interactions are combined within a neighborhood of interaction. Computer simulations of the model generate coherent motion at the global level and reproduce individual trajectories at the local level. This approach has yielded the first experiment-driven, bottom-up model of collective motion, providing a basis for understanding more complex patterns of crowd behavior in both everyday and emergency situations.

The combined effect of attraction and orientation zones in 2D flocking models

2016 ◽  
Vol 30 (04) ◽  
pp. 1650002 ◽  
Author(s):  
Tarras Iliass ◽  
Dorilson Cambui
Keyword(s):  
Collective Motion ◽  
Numerical Study ◽  
Biological Behavior ◽  
Behavior Patterns ◽  
Vicsek Model ◽  
Agent Based ◽  
Fish Schools ◽  
Behavioral Rules ◽  
Parallel Group ◽  
Kinetic Phase Transition

In nature, many animal groups, such as fish schools or bird flocks, clearly display structural order and appear to move as a single coherent entity. In order to understand the complex motion of these systems, we study the Vicsek model of self-propelled particles (SPP) which is an important tool to investigate the behavior of collective motion of live organisms. This model reproduces the biological behavior patterns in the two-dimensional (2D) space. Within the framework of this model, the particles move with the same absolute velocity and interact locally in the zone of orientation by trying to align their direction with that of the neighbors. In this paper, we model the collective movement of SPP using an agent-based model which follows biologically motivated behavioral rules, by adding a second region called the attraction zone, where each particles move towards each other avoiding being isolated. Our main goal is to present a detailed numerical study on the effect of the zone of attraction on the kinetic phase transition of our system. In our study, the consideration of this zone seems to play an important role in the cohesion. Consequently, in the directional orientation, the zone that we added forms the compact particle group. In our simulation, we show clearly that the model proposed here can produce two collective behavior patterns: torus and dynamic parallel group. Implications of these findings are discussed.

scholarly journals Swarming, swirling and stasis in sequestered bristle-bots

2013 ◽  
Vol 469 (2151) ◽  
pp. 20120637 ◽  
Author(s):  
L. Giomi ◽  
N. Hawley-Weld ◽  
L. Mahadevan
Keyword(s):  
Cell Phone ◽  
Autonomous Agents ◽  
Collective Motion ◽  
Relative Magnitude ◽  
Single Parameter ◽  
Local Interactions ◽  
Substrate Topography ◽  
Space And Time ◽  
Behavioural Repertoire

The collective ability of organisms to move coherently in space and time is ubiquitous in any group of autonomous agents that can move and sense each other and the environment. Here, we investigate the origin of collective motion and its loss using macroscopic self-propelled bristle-bots, simple automata made from a toothbrush and powered by an onboard cell phone vibrator-motor, that can sense each other through shape-dependent local interactions, and can also sense the environment non-locally via the effects of confinement and substrate topography. We show that when bristle-bots are confined to a limited arena with a soft boundary, increasing the density drives a transition from a disordered and uncoordinated motion to organized collective motion either as a swirling cluster or a collective dynamical stasis. This transition is regulated by a single parameter, the relative magnitude of spinning and walking in a single automaton. We explain this using quantitative experiments and simulations that emphasize the role of the agent shape, environment and confinement via boundaries. Our study shows how the behavioural repertoire of these physically interacting automatons controlled by one parameter translates into the mechanical intelligence of swarms.

scholarly journals Collision Avoidance Mechanism for Symmetric Circular Formations of Unitary Mass Autonomous Vehicles at Constant Speed

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Vander L. S. Freitas ◽  
Elbert E. N. Macau
Keyword(s):  
Data Collection ◽  
Collision Avoidance ◽  
Mobile Agents ◽  
Autonomous Vehicles ◽  
Coupled Oscillators ◽  
Collective Motion ◽  
Interconnection Network ◽  
Constant Speed ◽  
Local Interactions ◽  
Use Phase

Collective motion is a promising field that studies how local interactions lead groups of individuals to global behaviors. Biologists try to understand how those subjects interplay in nature, and engineers are concerned with the application of interaction strategies to mobile vehicles, satellites, robots, etc. There are several models in literature that employ strategies observed in groups of beings in nature. The aim is not to literally mimic them but to extract suitable strategies for the chosen application. These models, constituted of multiple mobile agents, can be used in tasks such as data collection, surveillance and monitoring. One approach is to use phase-coupled oscillators to design the mobile agents, in which each member is an oscillator and they are coupled according to an interconnection network. This design usually does not keep track and handle the possible collisions within the group, and real applications obviously must manage these situations to prevent the equipment from crashing. This paper introduces a collision avoidance mechanism to a model of particles with phase-coupled oscillators dynamics for symmetric circular formations.

scholarly journals Initiation and spread of escape waves within animal groups

2015 ◽  
Vol 2 (4) ◽  
pp. 140355 ◽  
Author(s):  
James E. Herbert-Read ◽  
Jerome Buhl ◽  
Feng Hu ◽  
Ashley J. W. Ward ◽  
David J. T. Sumpter
Keyword(s):  
Natural Selection ◽  
Simulation Model ◽  
Entire Group ◽  
Centralized Control ◽  
Local Interactions ◽  
Animal Groups ◽  
Fish Schools ◽  
Group Members ◽  
Group Density ◽  
Transfer Of Information

The exceptional reactivity of animal collectives to predatory attacks is thought to be owing to rapid, but local, transfer of information between group members. These groups turn together in unison and produce escape waves. However, it is not clear how escape waves are created from local interactions, nor is it understood how these patterns are shaped by natural selection. By startling schools of fish with a simulated attack in an experimental arena, we demonstrate that changes in the direction and speed by a small percentage of individuals that detect the danger initiate an escape wave. This escape wave consists of a densely packed band of individuals that causes other school members to change direction. In the majority of cases, this wave passes through the entire group. We use a simulation model to demonstrate that this mechanism can, through local interactions alone, produce arbitrarily large escape waves. In the model, when we set the group density to that seen in real fish schools, we find that the risk to the members at the edge of the group is roughly equal to the risk of those within the group. Our experiments and modelling results provide a plausible explanation for how escape waves propagate in nature without centralized control.

Intermittency and cascades

2000 ◽  
Vol 409 ◽  
pp. 99-120 ◽  
Author(s):  
JAVIER JIMÉNEZ
Keyword(s):  
Coherent Structures ◽  
Intensity Scale ◽  
Self Similarity ◽  
Local Interactions ◽  
Physical Systems ◽  
The Real ◽  
Multiplicative Cascades ◽  
Large Fluctuations ◽  
Non Local ◽  
The Right

The theory of intermittency in multiplicative cascades is reviewed, with special, but not exclusive, emphasis on its applications to turbulence. It is noted that, in many physical systems, this theory is incomplete, and two of its limitations are discussed in some detail. It is first argued that large fluctuations will in most cases behave differently from the lower-level background, since the overall mean introduces an intensity scale that breaks self-similarity, and that they will, under the right conditions, evolve into coherent structures decoupled from the rest of the system. The effect of non-local interactions is then addressed. It is shown that the results depend on the nature of the interaction, and that it is possible to generate non-local cascades which are less intermittent, as intermittent, or even more intermittent, than local ones. It is finally stressed that the multiplicative theory of cascades is a kinematic description, and that its relation with the real dynamics is not straightforward.

scholarly journals Computational exploration of treadmilling and protrusion growth observed in fire ant rafts

2021 ◽  
Author(s):  
Robert James Wagner ◽  
Franck J Vernerey
Keyword(s):  
Solenopsis Invicta ◽  
Swarm Robotics ◽  
Collective Motion ◽  
Active Matter ◽  
Local Interactions ◽  
Agent Based ◽  
Computational Exploration ◽  
In Fire ◽  
Cellular Aggregates

Condensed active matter systems regularly achieve cooperative emergent functions that individual constituents could not accomplish alone. The rafts of fire ants (Solenopsis invicta) are often studied in this context for their ability to create structures comprised entirely of their own bodies, including tether-like protrusions that facilitate exploration of flooded environments. While similar protrusions are observed in cytoskeletons and cellular aggregates, they are generally dependent on morphogens or external gradients leaving the isolated role of local interactions poorly understood. Here we demonstrate through an ant-inspired, agent-based numerical model how protrusions in ant rafts may emerge spontaneously due to local interactions and how phases of exploratory protrusion growth may be induced by increased ant activity. These results provide an example in which functional morphogenesis of condensed active matter may emerge purely from locally-driven collective motion and may provide a source of inspiration for the development of autonomous active matter and swarm robotics.

scholarly journals Super-individual based model for fish migration

2014 ◽  
Author(s):  
Petro Babak
Keyword(s):  
Collective Motion ◽  
Fish Migration ◽  
Computationally Efficient ◽  
Individual Based Model ◽  
Migration Patterns ◽  
Fish Schools ◽  
Fish School ◽  
Individual Based Models ◽  
Ecological Mechanisms ◽  
Large Groups

One of the most remarkable characteristics of collective motion of fish is the emergence of complex migration patterns in which swimming fish are synchronised by remaining together and moving in the same direction. These migration patterns, referred to as fish schools, are often explained using individual based models (IBM’s) that focus on interactions between single individuals. The IBM’s appear to be realistic and robust; however, they are computationally unable to efficiently describe migration of large groups of fish. Here, an approach for developing computationally efficient super-individual based models from simple individual based models for fish migration is proposed. This approach accentuates on ecological mechanisms underlying collective motion of fish, and interaction between them; it explicitly incorporates such important mechanisms in collective motion of fish as fish school splitting and merging.

scholarly journals From behavioural analyses to models of collective motion in fish schools

2012 ◽  
Vol 2 (6) ◽  
pp. 693-707 ◽  
Author(s):  
Ugo Lopez ◽  
Jacques Gautrais ◽  
Iain D. Couzin ◽  
Guy Theraulaz
Keyword(s):  
Statistical Physics ◽  
Collective Motion ◽  
Theoretical Biology ◽  
Quantitative Agreement ◽  
Point Of View ◽  
School Level ◽  
Fish Schools ◽  
Individual Level ◽  
Modelling Assumptions ◽  
The Individual

Fish schooling is a phenomenon of long-lasting interest in ethology and ecology, widely spread across taxa and ecological contexts, and has attracted much interest from statistical physics and theoretical biology as a case of self-organized behaviour. One topic of intense interest is the search of specific behavioural mechanisms at stake at the individual level and from which the school properties emerges. This is fundamental for understanding how selective pressure acting at the individual level promotes adaptive properties of schools and in trying to disambiguate functional properties from non-adaptive epiphenomena. Decades of studies on collective motion by means of individual-based modelling have allowed a qualitative understanding of the self-organization processes leading to collective properties at school level, and provided an insight into the behavioural mechanisms that result in coordinated motion. Here, we emphasize a set of paradigmatic modelling assumptions whose validity remains unclear, both from a behavioural point of view and in terms of quantitative agreement between model outcome and empirical data. We advocate for a specific and biologically oriented re-examination of these assumptions through experimental-based behavioural analysis and modelling.

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