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S Bouzat

Publications and source records attributed to S Bouzat.

4 recordsLinked to original sources

Dynamics of learning in coupled oscillators tutored with delayed reinforcements.

In this work we analyze the solutions of a simple system of coupled phase oscillators in which the connectivity is learned dynamically. The model is inspired by the process of learning of birdsongs by oscine birds. An oscillator acts as the generator of a basic rhythm and drives slave oscillators which are responsible for different motor actions. The driving signal arrives at each driven oscillator through two different pathways. One of them is a direct pathway. The other one is a reinforcement pathway, through which the signal arrives delayed. The coupling coefficients between the driving oscillator and the slave ones evolve in time following a Hebbian-like rule. We discuss the conditions under which a driven oscillator is capable of learning to lock to the driver. The resulting phase difference and connectivity are a function of the delay of the reinforcement. Around some specific delays, the system is capable of generating dramatic changes in the phase difference between the driver and the driven systems. We discuss the dynamical mechanism responsible for this effect and possible applications of this learning scheme.

Animals↗

Pattern dynamics in bidimensional oscillatory media with bistable inhomogeneities.

By means of numerical simulations, we study pattern dynamics in selected examples of inhomogeneous active media described by a reaction diffusion model of the activator-inhibitor type. We consider inhomogeneities corresponding to a variation in space of the (nonlinear) reaction characteristics of the system or the diffusion constants. Three different bidimensional systems are analyzed: an oscillatory medium in a square reactor with a circular central bistable domain, and cases of a bistable stripe immersed in an oscillatory medium in a trapezoidal reactor and in a rectangular reactor with inhomogeneous diffusion. The different types of complex behavior that arise in these systems are analyzed.

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Stochastic resonance in extended bistable systems: the role of potential symmetry.

We study the role of potential symmetry in a three-field reaction-diffusion system presenting bistability by means of a two-state theory for stochastic resonance in general asymmetric systems. By analyzing the influence of different parameters in the optimization of the signal-to-noise ratio, we observe that this magnitude always increases with the symmetry of the system's potential, indicating that it is this feature which governs the optimization of the system's response to periodic signals.

Journal Article↗

Reaction kinetics of diffusing particles injected into a reactive substrate.

We analyze the kinetics of trapping (A+B-->B) and annihilation (A+B-->0) processes on a one-dimensional substrate with homogeneous distribution of immobile B particles while the A particles are supplied by a localized source. For the imperfect reaction case, we analyze both problems by means of a stochastic model and compare the results with numerical simulations. In addition, we present the exact analytical results of the stochastic model for the case of perfect trapping.

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