1,089 research outputs found
Cooperation of Nature and Physiologically Inspired Mechanism in Visualisation
A novel approach of integrating two swarm intelligence algorithms is considered, one simulating the behaviour of birds flocking (Particle Swarm Optimisation) and the other one (Stochastic Diffusion Search) mimics the recruitment behaviour of one species of ants – Leptothorax acervorum. This hybrid algorithm is assisted by a biological mechanism inspired by the behaviour of blood flow and cells in blood vessels, where the concept of high and low blood pressure is utilised. The performance of the nature-inspired algorithms and the biologically inspired mechanisms in the hybrid algorithm is reflected through a cooperative attempt to make a drawing on the canvas. The scientific value of the marriage between the two swarm intelligence algorithms is currently being investigated thoroughly on many benchmarks and the results reported suggest a promising prospect (al-Rifaie, Bishop & Blackwell, 2011). We also discuss whether or not the ‘art works’ generated by nature and biologically inspired algorithms can possibly be considered as ‘computationally creative’
Resilience and Controllability of Dynamic Collective Behaviors
The network paradigm is used to gain insight into the structural root causes
of the resilience of consensus in dynamic collective behaviors, and to analyze
the controllability of the swarm dynamics. Here we devise the dynamic signaling
network which is the information transfer channel underpinning the swarm
dynamics of the directed interagent connectivity based on a topological
neighborhood of interactions. The study of the connectedness of the swarm
signaling network reveals the profound relationship between group size and
number of interacting neighbors, which is found to be in good agreement with
field observations on flock of starlings [Ballerini et al. (2008) Proc. Natl.
Acad. Sci. USA, 105: 1232]. Using a dynamical model, we generate dynamic
collective behaviors enabling us to uncover that the swarm signaling network is
a homogeneous clustered small-world network, thus facilitating emergent
outcomes if connectedness is maintained. Resilience of the emergent consensus
is tested by introducing exogenous environmental noise, which ultimately
stresses how deeply intertwined are the swarm dynamics in the physical and
network spaces. The availability of the signaling network allows us to
analytically establish for the first time the number of driver agents necessary
to fully control the swarm dynamics
Evolutionary swarm robotics: a theoretical and methodological itinerary from individual neuro-controllers to collective behaviours
In the last decade, swarm robotics gathered much attention in the research community. By drawing inspiration from social insects and other self-organizing systems, it focuses on large robot groups featuring distributed control, adaptation, high robustness, and flexibility. Various reasons lay behind this interest in similar multi-robot systems. Above all, inspiration comes from the observation of social activities, which are based on concepts like division of labor, cooperation, and communication. If societies are organized in such a way in order to be more efficient, then robotic groups also could benefit from similar paradigms
Model of deep non-volcanic tremor part I: ambient and triggered tremor
There is evidence of triggering of tremor by seismic waves emanating from
distant large earthquakes. The frequency contents of triggered and ambient
tremor are largely identical, suggesting that tremor does not depend directly
on the nature of the source. We show here that the model of plate dynamics
developed earlier by us is an appropriate tool for describing the onset of
tremor. In the framework of this model, tremor is an internal response of a
fault to a failure triggered by external disturbances. The model predicts
generation of radiation in a frequency range defined by the fault parameters.
Other specific features predicted are: the upper limit of the size of the
emitting area is a few dozen km; tremor accompanies earthquakes and aseismic
slip; the frequency content of tremor depends on the type of failure. The model
also explains why a tremor has no clear impulsive phase, in contrast to
earthquakes. A comparatively small effective normal stress (hence a high fluid
pressure) is required to make the model consistent with observed tremor
parameters. Our model indicates that tremor is not necessarily a superposition
of low frequency earthquakes, as commonly assumed, although the latter may
trigger them. The approach developed complements the conventional viewpoint
which assumes that tremor reflects a frictional process with low rupture speed.
Essentially our model adds the hypothesis that resonant-type oscillations exist
inside a fault. This addition may change our understanding of the nature of
tremor in general, and the methods of its identification and location in
particular.Comment: 32 pages, 16 figures. arXiv admin note: text overlap with
arXiv:1202.091
Multi-agent decision-making dynamics inspired by honeybees
When choosing between candidate nest sites, a honeybee swarm reliably chooses
the most valuable site and even when faced with the choice between near-equal
value sites, it makes highly efficient decisions. Value-sensitive
decision-making is enabled by a distributed social effort among the honeybees,
and it leads to decision-making dynamics of the swarm that are remarkably
robust to perturbation and adaptive to change. To explore and generalize these
features to other networks, we design distributed multi-agent network dynamics
that exhibit a pitchfork bifurcation, ubiquitous in biological models of
decision-making. Using tools of nonlinear dynamics we show how the designed
agent-based dynamics recover the high performing value-sensitive
decision-making of the honeybees and rigorously connect investigation of
mechanisms of animal group decision-making to systematic, bio-inspired control
of multi-agent network systems. We further present a distributed adaptive
bifurcation control law and prove how it enhances the network decision-making
performance beyond that observed in swarms
Hysteretic behavior of spatially coupled phase-oscillators
Motivated by phenomena related to biological systems such as the
synchronously flashing swarms of fireflies, we investigate a network of phase
oscillators evolving under the generalized Kuramoto model with inertia. A
distance-dependent, spatial coupling between the oscillators is considered.
Zeroth and first order kernel functions with finite kernel radii were chosen to
investigate the effect of local interactions. The hysteretic dynamics of the
synchronization depending on the coupling parameter was analyzed for different
kernel radii. Numerical investigations demonstrate that (1) locally locked
clusters develop for small coupling strength values, (2) the hysteretic
behavior vanishes for small kernel radii, (3) the ratio of the kernel radius
and the maximal distance between the oscillators characterizes the behavior of
the network
Active Brownian Particles. From Individual to Collective Stochastic Dynamics
We review theoretical models of individual motility as well as collective
dynamics and pattern formation of active particles. We focus on simple models
of active dynamics with a particular emphasis on nonlinear and stochastic
dynamics of such self-propelled entities in the framework of statistical
mechanics. Examples of such active units in complex physico-chemical and
biological systems are chemically powered nano-rods, localized patterns in
reaction-diffusion system, motile cells or macroscopic animals. Based on the
description of individual motion of point-like active particles by stochastic
differential equations, we discuss different velocity-dependent friction
functions, the impact of various types of fluctuations and calculate
characteristic observables such as stationary velocity distributions or
diffusion coefficients. Finally, we consider not only the free and confined
individual active dynamics but also different types of interaction between
active particles. The resulting collective dynamical behavior of large
assemblies and aggregates of active units is discussed and an overview over
some recent results on spatiotemporal pattern formation in such systems is
given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte
- …