Arturo Buscarino

Effects of mobility in a population of prisoner's dilemma players.

We address the problem of how the survival of cooperation in a social system depends on the motion of the individuals. Specifically, we study a model in which prisoners dilemma players are allowed to move in a two-dimensional plane. Our results show that cooperation can survive in such a system provided that both the temptation to defect and the velocity at which agents move are not too high. Moreover, we show that when these conditions are fulfilled, the only asymptotic state of the system is that in which all players are cooperators. Our results might have implications for the design of cooperative strategies in motion coordination and other applications including wireless networks.

A chaotic circuit based on Hewlett-Packard memristor.

Memristors are gaining increasing attention as next generation electronic devices. They are also becoming commonly used as fundamental blocks for building chaotic circuits, although often arbitrary (typically piece-wise linear or cubic) flux-charge characteristics are assumed. In this paper, a chaotic circuit based on the mathematical realistic model of the HP memristor is introduced. The circuit makes use of two HP memristors in antiparallel. Numerical results showing some of the chaotic attractors generated by this circuit and the behavior with respect to changes in its component values are described.

Design of Time-Delay Chaotic Electronic Circuits

This paper investigates the problem of the design and the implementation of time-delay chaotic circuits. A simple feedback scheme consisting of a nonlinearity, a first-order RC circuit and a delay block has been fixed and a procedure to design the characteristics of these blocks in order to obtain chaotic dynamics has been introduced. A series of n Bessel filters in cascade is used to implement the time-delay. The suitability of the approach is demonstrated with an example: a new chaotic circuit has been first designed and, then, implemented with off-the-shelf discrete components. The approach allows us to design and implement a new class of time-delay chaotic circuits with simple components, like resistors, capacitors, and operational amplifiers.

MEMRISTIVE CHAOTIC CIRCUITS BASED ON CELLULAR NONLINEAR NETWORKS

Memristors are gaining increasing interest in the scientific community for their possible applications, e.g. high-speed low-power processors or new biological models for associative memories. Due t...

Chimera states in time-varying complex networks.

Chimera states have been recently found in a variety of different coupling schemes and geometries. In most cases, the underlying coupling structure is considered to be static, while many realistic systems display significant temporal changes in the pattern of connectivity. In this work we investigate a time-varying network made of two coupled populations of Kuramoto oscillators, where the links between the two groups are considered to vary over time. As a main result we find that the network may support stable, breathing, and alternating chimera states. We also find that, when the rate of connectivity changes is fast, compared to the oscillator dynamics, the network may be described by a low-dimensional system of equations. Unlike in the static heterogeneous case, the onset of alternating chimera states is due to the presence of fluctuations, which may be induced either by the finite size of the network or by large switching times.

A GALLERY OF CHAOTIC OSCILLATORS BASED ON HP MEMRISTOR

This work deals with the design of chaotic circuits based on memristors modeled as in [Strukov et al., 2008]. This physical model has the capability of capturing the behavior of the TiO2 memristor ...

Disease spreading in populations of moving agents

We study the effect of motion on disease spreading in a system of random walkers which additionally perform long-distance jumps. A small percentage of jumps in the agent motion is sufficient to destroy the local correlations and to produce a large drop in the epidemic threshold, that we explain in terms of a mean-field approximation. This effect is similar to the crossover found in static small-world networks, and can be furthermore linked to the structural properties of the dynamical network of agent interactions.

Dynamical network interactions in distributed control of robots

In this paper the dynamical network model of the interactions within a group of mobile robots is investigated and proposed as a possible strategy for controlling the robots without central coordination. Motivated by the results of the analysis of our simple model, we show that the system performance in the presence of noise can be improved by including long-range connections between the robots. Finally, a suitable strategy based on this model to control exploration and transport is introduced.

Memristor-Based Adaptive Coupling for Consensus and Synchronization

A configuration of two memristors connected with opposite polarity is proposed to realize an adaptive law for consensus and synchronization. This configuration allows one to couple two systems so that the memristor memory variables regulate the coupling strength and dynamically evolve as a function of the mismatches between the units. A physical-based model capturing the main feature of TiO2 memristors is used for our study. Adaptive consensus of two integrators and adaptive synchronization of two chaotic circuits are investigated, and, then, extended to the case of more than two units coupled into a network configuration. The approach provides an effective strategy for the analog implementation of adaptive laws at the circuit level, as the proposed coupling configuration consists of only two components.

CHAOS DOES HELP MOTION CONTROL

This work consists in the realization and control of a walking microrobot actuated by piezoelectric materials. Usually, the actuation of robot legs is controlled by square wave signals characterized by fixed amplitude and frequency. In this work the control signals are generated performing a frequency modulation driven by the chaotic evolution of Chuas circuit state variables. The smooth changes of the actuation signal frequency, performed by our chaotic system, enhance the microrobot walking capabilities especially when walking on given surfaces.