Skip to Main content Skip to Navigation
Theses

Contribution à la théorie des ondelettes : application à la turbulence des plasmas de bord de Tokamak et à la mesure dimensionnelle de cibles

Abstract : The necessary scale-based representation of the world leads us to explain why the wavelet theory is the best suited formalism. Its performances are compared to other tools: R/S analysis and empirical modal decomposition method (EMD). The great diversity of analyzing bases of wavelet theory leads us to propose a morphological approach of the analysis. The study is organized into three parts. The first chapter is dedicated to the constituent elements of wavelet theory. Then we will show the surprising link existing between recurrence concept and scale analysis (Daubechies polynomials) by using Pascal's triangle. A general analytical expression of Daubechies' filter coefficients is then proposed from the polynomial roots. The second chapter is the first application domain. It involves edge plasmas of tokamak fusion reactors. We will describe how, for the first time on experimental signals, the Hurst coefficient has been measured by a wavelet-based estimator. We will detail from fbm-like processes (fractional Brownian motion), how we have established an original model perfectly reproducing fBm and fGn joint statistics that characterizes magnetized plasmas. Finally, we will point out the reasons that show the lack of link between high values of the Hurst coefficient and possible long correlations. The third chapter is dedicated to the second application domain which is relative to the backscattered echo analysis of an immersed target insonified by an ultrasonic plane wave. We will explain how a morphological approach associated to a scale analysis can extract the diameter information
Document type :
Theses
File URL :
http://docnum.univ-lorraine.fr/prive/SCD_T_2010_0125_SCIPIONI.pdf
Complete list of metadata

https://hal.univ-lorraine.fr/tel-01746379
Contributor : Thèses Ul <>
Submitted on : Thursday, March 29, 2018 - 10:32:53 AM
Last modification on : Friday, March 6, 2020 - 10:00:47 AM

Identifiers

  • HAL Id : tel-01746379, version 1

Collections

Citation

Angel Scipioni. Contribution à la théorie des ondelettes : application à la turbulence des plasmas de bord de Tokamak et à la mesure dimensionnelle de cibles. Autre. Université Henri Poincaré - Nancy 1, 2010. Français. ⟨NNT : 2010NAN10125⟩. ⟨tel-01746379⟩

Share

Metrics

Record views

28