Biomedical subjects

N Sungar

Publications and source records attributed to N Sungar.

3 recordsLinked to original sources

PubMed2006

Pattern stabilization through parameter alternation in a nonlinear optical system.

We report the first experimental realization of pattern formation in a spatially extended nonlinear system when the system is alternated between two states, neither of which exhibits patterning. Dynamical equations modeling the system are used for both numerical simulations and a weakly nonlinear analysis of the patterned states. The simulations show excellent agreement with the experiment. The nonlinear analysis provides an explanation of the patterning under alternation and accurately predicts both the observed dependence of the patterning on the frequency of alternation and the measured spatial frequencies of the patterns.

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PubMed2003

Stochastic resonance on two-dimensional arrays of bistable oscillators in a nonlinear optical system.

We describe an experimental realization of stochastic resonance in two-dimensional arrays of coupled nonlinear oscillators. The experiment is implemented using an optoelectronic system composed of a liquid crystal light valve in a feedback loop with external, spatially variable noise being added through a liquid crystal display. The behavior of the system differs from previously studied uniform arrays, showing a high signal-to-noise ratio at the output for a broad range of input noise. We show that this behavior is qualitatively the same as that exhibited by computer models where the nonlinear elements of the array have a distribution of biases applied to their switching thresholds.

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PubMed2000

Stochastic resonance in two-dimensional arrays of coupled nonlinear oscillators

In this Brief Report we report the results of computer simulations on the periodic and noise driving of two-dimensional square arrays of coupled nonlinear oscillators. We find significant improvement in the output of these arrays over their one-dimensional counterparts (quantified by signal-to-noise ratio in the power spectrum at the frequency of the periodic driving). We also find that, within the limited resolution of our simulations, the one-dimensional scaling laws proposed by Lindner et al. [Phys. Rev. E 53, 2081 (1996)] seem to hold quite well for two-dimensional arrays.

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