Search results for "Nonlinear dynamical system"

showing 3 items of 13 documents

Experimental and numerical enhancement of Vibrational Resonance in a neural circuit

2012

International audience; A neural circuit exactly ruled by the FitzHugh-Nagumo equations is excited by a biharmonic signal of frequencies f and F with respective amplitudes A and B. The magnitude spectrum of the circuit response is estimated at the low frequency driving f and presents a resonant behaviour versus the amplitude B of the high frequency. For the first time, it is shown experimentally that this Vibrational Resonance effect is much more pronounced when the two frequencies are multiple. This novel enhancement is also confirmed by numerical predictions. Applications of this nonlinear effect to the detection of weak stimuli are finally discussed.

[ PHYS.COND.CM-DS-NN ] Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn]02 engineering and technologyLow frequency01 natural sciencesSignalVibrational ResonanceNuclear magnetic resonance[NLIN.NLIN-PS]Nonlinear Sciences [physics]/Pattern Formation and Solitons [nlin.PS]0103 physical sciences0202 electrical engineering electronic engineering information engineeringVibrational resonance[ NLIN.NLIN-PS ] Nonlinear Sciences [physics]/Pattern Formation and Solitons [nlin.PS][PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn]Electrical and Electronic Engineering010306 general physicsMathematicsQuantitative Biology::Neurons and Cognition020208 electrical & electronic engineering[SPI.TRON]Engineering Sciences [physics]/ElectronicsComputational physics[ SPI.TRON ] Engineering Sciences [physics]/ElectronicsNonlinear systemAmplitudeExcited stateNonlinear resonanceBiharmonic equationNonlinear dynamical systemsFitzHugh-Nagumo
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System identification via optimised wavelet-based neural networks

2003

Nonlinear system identification by means of wavelet-based neural networks (WBNNs) is presented. An iterative method is proposed, based on a way of combining genetic algorithms (GAs) and least-square techniques with the aim of avoiding redundancy in the representation of the function. GAs are used for optimal selection of the structure of the WBNN and the parameters of the transfer function of its neurones. Least-square techniques are used to update the weights of the net. The basic criterion of the method is the addition of a new neurone, at a generic step, to the already constructed WBNN so that no modification to the parameters of its neurones is required. Simulation experiments and compa…

least squares approximations nonlinear dynamical systems identification neural nets iterative methods genetic algorithmsQuantitative Biology::Neurons and CognitionArtificial neural networkNonlinear system identificationIterative methodComputer scienceSystem identificationTransfer functionWaveletSettore ING-INF/04 - AutomaticaControl and Systems EngineeringControl theoryRedundancy (engineering)Electrical and Electronic EngineeringRepresentation (mathematics)InstrumentationAlgorithmIEE Proceedings - Control Theory and Applications
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Numerical methods for a nonlinear impact model: A comparative study with closed-form corrections

2011

A physically based impact model-already known and exploited in the field of sound synthesis-is studied using both analytical tools and numerical simulations. It is shown that the Hamiltonian of a physical system composed of a mass impacting on a wall can be expressed analytically as a function of the mass velocity during contact. Moreover, an efficient and accurate approximation for the mass outbound velocity is presented, which allows to estimate the Hamiltonian at the end of the contact. Analytical results are then compared to numerical simulations obtained by discretizing the system with several numerical methods. It is shown that, for some regions of the parameter space, the trajectorie…

sound synthesis0209 industrial biotechnologyMathematical optimizationnumerical analysisaudio signal processingAcoustics and UltrasonicsDiscretizationComputer sciencePhysical system02 engineering and technologyParameter spaceEnergy conservationsymbols.namesake020901 industrial engineering & automation0202 electrical engineering electronic engineering information engineeringElectrical and Electronic EngineeringComputer simulationSettore INF/01 - Informaticasound synthesis; numerical analysis; audio signal processingNumerical analysisMathematical analysisphysics computing020207 software engineeringimpact modelingimpact soundsEnergy conservationNonlinear systemnumerical simulationsymbolsnonlinear dynamical systemHamiltonian (quantum mechanics)
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