Influence of repulsion zone in the directional alignment of self-propelled particles

2014 ◽  
Vol 28 (15) ◽  
pp. 1450094 ◽  
Author(s):  
Dorilson Cambui
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
Biological Systems ◽  
Nearest Neighbors ◽  
Animal Groups ◽  
Rule Set ◽  
Directional Alignment ◽  
Interaction Rule

Collective behavior in animal groups such as schools of fish, swarms of insects or flocks of birds, although a phenomenon widely studied in biological systems, is subject of great interdisciplinary interest. An important tool to describe the dynamics of collective motion and ordered live organisms is the concept of self-propelled particles. Proposed by Vicsek and collaborators, it was considered in this model only as an (single) interaction rule, set as alignment, where particles align to motion the nearest neighbors. In this paper, we have considered a variant of this model by adding a second rule called repulsion zone, where particles repel each other at short distances, in order to investigate the influence of this zone on directional order of the particles.

scholarly journals Collective motion in biological systems

2012 ◽  
Vol 2 (6) ◽  
pp. 689-692 ◽  
Author(s):  
Andreas Deutsch ◽  
Guy Theraulaz ◽  
Tamas Vicsek
Keyword(s):  
Collective Motion ◽  
Biological Systems

scholarly journals Active sensing in groups: (what) do bats hear in the sonar cocktail party nightmare?

2019 ◽  
Author(s):  
Thejasvi Beleyur ◽  
Holger R. Goerlitz
Keyword(s):  
Group Size ◽  
Collective Behavior ◽  
Sensory Input ◽  
Nearest Neighbors ◽  
Active Sensing ◽  
Cocktail Party ◽  
Loud Calls ◽  
Sensory Strategies ◽  
Collective Group ◽  
Echo Detection

ABSTRACTActive sensing animals perceive their surroundings by emitting probes of energy and analyzing how the environment modulates these probes. However, the probes of conspecifics can jam active sensing, which should cause problems for groups of active sensing animals. This problem was termed the cocktail party nightmare for echolocating bats: as bats listen for the faint returning echoes of their loud calls, these echoes will be masked by the loud calls of other close-by bats. Despite this problem, many bats echolocate in groups and roost socially. Here, we present a biologically parametrized framework to quantify echo detection in groups. Incorporating known properties of echolocation, psychoacoustics, spatial acoustics and group flight, we quantify how well bats flying in groups can detect each other despite jamming. A focal bat in the center of a group can detect neighbors for group sizes of up to 100 bats. With increasing group size, fewer and only the closest and frontal neighbors are detected. Neighbor detection is improved for longer call intervals, shorter call durations, denser groups and more variable flight and sonar beam directions. Our results provide the first quantification of the sensory input of echolocating bats in collective group flight, such as mating swarms or emergences. Our results further generate predictions on the sensory strategies bats may use to reduce jamming in the cocktail party nightmare. Lastly, we suggest that the spatially limited sensory field of echolocators leads to limited interactions within a group, so that collective behavior is achieved by following only nearest neighbors.SIGNIFICANCE STATEMENTClose-by active sensing animals may interfere with each other. We investigated if and what many echolocators fly in a group hear – can they detect each other after all? We modelled acoustic and physical properties in group echolocation to quantify neighbor detection probability as group size increases. Echolocating bats can detect at least one of their closest neighbors per call up to group sizes of even 100 bats. Call parameters such as call rate and call duration play a strong role in how much echolocators in a group interfere with each other. Even when many bats fly together, they are indeed able to detect at least their nearest frontal neighbors – and this prevents them from colliding into one another.

scholarly journals Oscillating collective motion of active rotors in confinement

2020 ◽  
Vol 117 (22) ◽  
pp. 11901-11907 ◽  
Author(s):  
Peng Liu ◽  
Hongwei Zhu ◽  
Ying Zeng ◽  
Guangle Du ◽  
Luhui Ning ◽  
...  
Keyword(s):  
Collective Behavior ◽  
Collective Motion ◽  
Dynamic Structure ◽  
Packing Fraction ◽  
Frictional Stress ◽  
Active Matter ◽  
Active Particles ◽  
Particle Level ◽  
Inhomogeneous Density ◽  
Oscillation Properties

Due to its inherent out-of-equilibrium nature, active matter in confinement may exhibit collective behavior absent in unconfined systems. Extensive studies have indicated that hydrodynamic or steric interactions between active particles and boundary play an important role in the emergence of collective behavior. However, besides introducing external couplings at the single-particle level, the confinement also induces an inhomogeneous density distribution due to particle-position correlations, whose effect on collective behavior remains unclear. Here, we investigate this effect in a minimal chiral active matter composed of self-spinning rotors through simulation, experiment, and theory. We find that the density inhomogeneity leads to a position-dependent frictional stress that results from interrotor friction and couples the spin to the translation of the particles, which can then drive a striking spatially oscillating collective motion of the chiral active matter along the confinement boundary. Moreover, depending on the oscillation properties, the collective behavior has three different modes as the packing fraction varies. The structural origins of the transitions between the different modes are well identified by the percolation of solid-like regions or the occurrence of defect-induced particle rearrangement. Our results thus show that the confinement-induced inhomogeneity, dynamic structure, and compressibility have significant influences on collective behavior of active matter and should be properly taken into account.

scholarly journals Conformity in the collective: differences in hunger affect individual and group behavior in a shoaling fish

2019 ◽  
Vol 30 (4) ◽  
pp. 968-974 ◽  
Author(s):  
Alexander D M Wilson ◽  
Alicia L J Burns ◽  
Emanuele Crosato ◽  
Joseph Lizier ◽  
Mikhail Prokopenko ◽  
...  
Keyword(s):  
Collective Behavior ◽  
Nearest Neighbor ◽  
Collective Motion ◽  
Internal State ◽  
Group Behavior ◽  
Fundamental Interest ◽  
Individual Level ◽  
Group Members ◽  
The Individual ◽  
Nearest Neighbor Distances

Abstract Animal groups are often composed of individuals that vary according to behavioral, morphological, and internal state parameters. Understanding the importance of such individual-level heterogeneity to the establishment and maintenance of coherent group responses is of fundamental interest in collective behavior. We examined the influence of hunger on the individual and collective behavior of groups of shoaling fish, x-ray tetras (Pristella maxillaris). Fish were assigned to one of two nutritional states, satiated or hungry, and then allocated to 5 treatments that represented different ratios of satiated to hungry individuals (8 hungry, 8 satiated, 4:4 hungry:satiated, 2:6 hungry:satiated, 6:2 hungry:satiated). Our data show that groups with a greater proportion of hungry fish swam faster and exhibited greater nearest neighbor distances. Within groups, however, there was no difference in the swimming speeds of hungry versus well-fed fish, suggesting that group members conform and adapt their swimming speed according to the overall composition of the group. We also found significant differences in mean group transfer entropy, suggesting stronger patterns of information flow in groups comprising all, or a majority of, hungry individuals. In contrast, we did not observe differences in polarization, a measure of group alignment, within groups across treatments. Taken together these results demonstrate that the nutritional state of animals within social groups impacts both individual and group behavior, and that members of heterogenous groups can adapt their behavior to facilitate coherent collective motion.

scholarly journals Mechanical spectroscopy of insect swarms

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw9305 ◽  
Author(s):  
Kasper van der Vaart ◽  
Michael Sinhuber ◽  
Andrew M. Reynolds ◽  
Nicholas T. Ouellette
Keyword(s):  
Information Flow ◽  
Collective Behavior ◽  
Mechanical Spectroscopy ◽  
Bulk Materials ◽  
Animal Groups ◽  
Environmental Perturbations ◽  
Storage And Loss Moduli ◽  
Social Animals ◽  
In The Wild ◽  
Flow Through

Social animals routinely form groups, which are thought to display emergent, collective behavior. This hypothesis suggests that animal groups should have properties at the group scale that are not directly linked to the individuals, much as bulk materials have properties distinct from those of their constituent atoms. Materials are often probed by measuring their response to controlled perturbations, but these experiments are difficult to conduct on animal groups, particularly in the wild. Here, we show that laboratory midge swarms have emergent continuum mechanical properties, displaying a collective viscoelastic response to applied oscillatory visual stimuli that allows us to extract storage and loss moduli for the swarm. We find that the swarms strongly damp perturbations, both viscously and inertially. Thus, unlike bird flocks, which appear to use collective behavior to promote lossless information flow through the group, our results suggest that midge swarms use it to stabilize themselves against environmental perturbations.

scholarly journals Collective behavior emerges from genetically controlled simple behavioral motifs in zebrafish

2021 ◽  
Author(s):  
Ariel C. Aspiras ◽  
Roy Harpaz ◽  
Sydney Chambule ◽  
Sierra Tseng ◽  
Florian Engert ◽  
...  
Keyword(s):  
Larval Stage ◽  
Visual Motion ◽  
Collective Motion ◽  
Group Behavior ◽  
Visual Responses ◽  
Animal Groups ◽  
Collective Behaviors ◽  
Early Larval Stage ◽  
Model Simulations ◽  
Species Survival

AbstractSince Darwin, coordinated movement of animal groups has been believed to be essential to species survival, but it is not understood how changes in the genetic makeup of individuals might alter behavior of the collective. Here we find that even at the early larval stage, zebrafish regulate their proximity and alignment with each other. Two simple visual responses, one that measures relative visual field occupancy and the other global visual motion, suffice to account for the group behavior that emerges. We analyze how mutations in genes known to affect social behavior of humans perturb these simple reflexes in larval zebrafish and thereby affect their collective behaviors. We use model simulations to show that changes in reflexive responses of individual mutant animals predict well the distinctive collective patterns that emerge in a group. Hence group behaviors reflect in part genetically defined primitive sensorimotor “motifs”, which are evident even in young larvae.Long AbstractCoordinated movement of animal groups is essential to species survival. It is not clear whether there are simple interactions among the individuals that account for group behaviors, nor when they arise during development. Zebrafish at the early larval stage do not manifest obvious tendencies to form groups, but we find here that they have already established mechanisms to regulate proximity and alignment with respect to their neighbors, which are the two key ingredients of shoaling and schooling. Specifically, we show that two basic reflexes are sufficient to explain a large part of emerging collective behaviors. First, young larvae repel away from regions of high visual clutter, leading to a dispersal of the group. At later developmental stages, this dispersal reflex shifts to attraction and aggregation behaviors. Second, larvae display a strong tendency to move along with whole field motion stimuli, a well-described behavior known as the optomotor reflex (OMR). When applied to individuals swimming within a group, this reflex leads to an emergence of mutual alignment between close neighbors and induces collective motion of the whole group. The combined developmental maturation of both reflexes can then explain emergent shoaling and schooling behavior.In order to probe the link between single genetic mutations and emergent collective motion, we select fish with mutations in genes orthologous to those associated with human behavioral disorders and find that these mutations affect the primitive visuomotor behaviors at a very young age and persist over development. We then use model simulations to show that the phenotypic manifestations of these mutations are predictive of changes in the emergent collective behaviors of mutant animals. Indeed, models based solely on these two primitive motor reflexes can synergistically account for a large fraction of the distinctive emergent group behaviors across ages and genetic backgrounds. Our results indicate that complex interactions among individuals in a group are built upon genetically defined primitive sensorimotor “motifs”, which are evident even in young larvae at a time when the nervous system is far less complex and more directly accessible to detailed analysis.

scholarly journals Emergence of self-organized multivortex states in flocks of active rollers

2020 ◽  
Vol 117 (18) ◽  
pp. 9706-9711 ◽  
Author(s):  
Koohee Han ◽  
Gašper Kokot ◽  
Oleh Tovkach ◽  
Andreas Glatz ◽  
Igor S. Aranson ◽  
...  
Keyword(s):  
Computational Modeling ◽  
Collective Behavior ◽  
Rotational Motion ◽  
Collective Motion ◽  
Self Organization ◽  
Design Strategies ◽  
Vortex Phase ◽  
Active Elements ◽  
Self Organized ◽  
Dynamic Materials

Active matter, both synthetic and biological, demonstrates complex spatiotemporal self-organization and the emergence of collective behavior. A coherent rotational motion, the vortex phase, is of great interest because of its ability to orchestrate well-organized motion of self-propelled particles over large distances. However, its generation without geometrical confinement has been a challenge. Here, we show by experiments and computational modeling that concentrated magnetic rollers self-organize into multivortex states in an unconfined environment. We find that the neighboring vortices more likely occur with the opposite sense of rotation. Our studies provide insights into the mechanism for the emergence of coherent collective motion on the macroscale from the coupling between microscale rotation and translation of individual active elements. These results may stimulate design strategies for self-assembled dynamic materials and microrobotics.

COLLECTIVE BEHAVIOR OF INTERACTING PARTICLES: RADIUS-DEPENDENT PHASE TRANSITION

2013 ◽  
Vol 27 (04) ◽  
pp. 1350028 ◽  
Author(s):  
I. TARRAS ◽  
N. MOUSSA ◽  
M. MAZROUI ◽  
Y. BOUGHALEB ◽  
A. HAJJAJI
Keyword(s):  
Phase Transition ◽  
Collective Behavior ◽  
Collective Motion ◽  
Simulation Method ◽  
Critical Value ◽  
Original Model ◽  
Multi Agent System ◽  
Interacting Particles ◽  
Main Motivation ◽  
Multi Agent

The aim of this paper is to study and discuss the effect of three zones (repulsion zone, orientation zone and attraction zone) on the phase transition in 2D-collective moving particles. Our main motivation is to better understand the complex behavior of non-equilibrium multi-agent system by extending the earlier and original model proposed by Viscek et al. [T. Viscek et al., Phys. Rev. Lett.75 (1995) 1226] for one zone. The analysis is performed over different situations by using a numerical simulation method. It is found that the radius R2 of orientation zone plays an important role in the system. In effect, by varying the parameter R2 a phase transition can be achieved from disordered moving of individuals to a group to highly aligned collective motion. The results also show that, the critical value of R2 at which the transition emerges depends strongly on the size of the repulsion zone but not on the size of attraction one.

scholarly journals Compound-V formations in shorebird flocks

2019 ◽  
Author(s):  
Aaron J. Corcoran ◽  
Tyson L. Hedrick
Keyword(s):  
Nearest Neighbor ◽  
Migratory Birds ◽  
Nearest Neighbors ◽  
Sparse Sampling ◽  
Emergent Properties ◽  
Mixed Species ◽  
Lateral Distance ◽  
Mixed Species Flocks ◽  
Interaction Rule ◽  
Species Flocks

AbstractAnimal groups have emergent properties that result from simple interactions among individuals. However, we know little about why animals adopt different interaction rules because of sparse sampling among species. Here, we identify an interaction rule that holds across single and mixed-species flocks of four migratory shorebird species spanning a seven-fold range of body masses. The rule, aligning with a 1-wingspan lateral distance to nearest neighbors in the same horizontal plane, scales linearly with wingspan but is independent of nearest neighbor distance and neighbor species. This rule propagates outward to create a global flock structure that we term the compound-V formation. We propose that this formation represents an intermediary between the cluster flocks of starlings and the simple-V formations of geese and other large migratory birds. Analysis of individual wingbeat frequencies and airspeeds indicates that the compound-V formation may be an adaptation for aerodynamic flocking.

Sign in / Sign up

Export Citation Format

Share Document