Search results for "bruit"
showing 5 items of 15 documents
Noise contribution to resonance phenomena and information propagation in non linear electronic networks
2015
This manuscript presents research aiming to show possible positive effects of deterministic and stochastic perturbations on the responses of different nonlinear systems. To that end, both numerical and experimental studies were carried out on two kinds of structures : an elementary electronic FitzHugh-Nagumo oscillator and an electrical line developed by resistively coupling 45 elementary cells. In the first section, the elementary cell characterization was undertaken in a deterministic regime. In the presence of a bichromatic stimulus, it is shown that when the low frequency component is subthreshold, its detection can be maximized for an optimal magnitude of the second component thanks to…
Electronic implementation of a non-linear oscillator subjected to noise : application to the modeling of neuronal information coding
2011
We study the nonlinear FitzHugh-Nagumo model witch describes the dynamics of excitable neural element. It is well known that this system exhibits three different possible responses. Indeed, the system can be mono-stable, oscillatory or bistable. In the oscillatory regime, the system periodically responds by generating action potential. By contrast, in the mono-stable state the system response remains constant after a transient. Under certain conditions, the system can undergo a bifurcation between the stable and the oscillatory regime via the so called Andronov-Hopf bifurcation. In this Phd thesis, we consider the FitzHugh-Nagumo model in the stable state, that is set near the Andronov-Hopf…
Exposition environnementale au bruit et à la pollution de l'air au cours de la grossesse avec comorbidités associées
2018
L’objectif était d’analyser le lien entre l’exposition environnementale au bruit et à la pollution de l’air en milieu urbain et la prématurité chez les femmes dont le risque d’accouchement prématuré était augmenté par la présence d’une ou plusieurs comorbidités. Méthode. Une étude cas-témoins a été conduite sur les grossesses uniques accompagnées d’au moins une comorbidité. Les accouchements ont eu au CHU de Besançon ou de Dijon entre 2005 et 2009. Le niveau sonore de nuit (Lnight en façade du bâtiment d’habitation) et la concentration en dioxyde d’azote (NO2) dans les 50 m autour de l’habitation ont été modélisés à l’adresse déclarée au moment de l’accouchement. Une régression logistique c…
Aspects acoustique et sensoriel du bruit
2008
National audience
Spatiocolorimetric neighborhood hypergraph and Image Processing Applications : Noise Removal and Edge Detection.
2004
In this document, we are interested in image modeling by the means of the hypergraph theory. Our contribution is essentially centered on the determination of the properties resulting from this theory and on the analysis from their adequacy with image problems, particularly edge and noise detection.First, we study the image spatiocolorimetric neighborhood hypergraph representation. Three representations are respectively presented incorporating global properties, local properties and similarity functions. Then, we use the hypergraph properties generated by the representation in order to define the structural models of noise and edge. This enables us to deduce the algorithms of noise suppressi…