HDR : Ondes, interactions et information : contributions dans une approche modélisation

Abstract:

The work presented for my HDR offers an overview of the research activities carried out since my doctoral thesis in 2000. Although my scientific background, since this doctorate, has been varied and has addressed different issues, it seems retrospectively that all my research is really based on the three key concepts of waves, interactions with the environment and the information carried by these waves.

A first part is devoted to my thesis theme which was the modeling of acoustic diffusion by a cylinder near a penetrable plane interface. Within the framework of modal theory, the objective was to build a generalization of the image method.

The following section presents my activities at a biomedical research center dedicated to the exploration of brain activity. With experimental tools such as Magnetic Resonance Imaging, Magneto-encephalography and Electroencephalography, the problem was to identify this activity according to pathologies or pharmaceutical treatments by approaches of signal treatment or modeling and then inversion.

Several chapters are then devoted to my activities at ENSTA Bretagne in remote sensing for maritime environments. The first approaches to modeling electromagnetic diffusion by sea surfaces were to consider them as rough surfaces with given statistical characteristics and to apply asymptotic electromagnetic models. Secondly, my activities have focused more on modeling the interaction of electromagnetic waves with moving deterministic sea surfaces, especially breaking waves. Subsequently, I set out to consider statistical moving sea surfaces and to see to what extent the diffused electromagnetic field could be described by nonlinear stochastic equations systems.

The last part of my manuscript addresses the use of Shannon’s information theory for wave phenomena. A first application focuses on a classical physics theme in electronic warfare. The second application, which is the subject of my most recent work, is in the context of quantum physics and more precisely on the subject of quantum illumination radar.