Maïtine Bergounioux

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This paper deals with a method of tomographic reconstruction of radially symmetric objects from a single radiograph, in order to study the behavior of shocked material. The usual tomographic reconstruction algorithms such as generalized inverse or filtered back-projection cannot be applied here because data are very noisy and the inverse problem associated(More)
In this paper we investigate optimal control problems governed by elliptic variational inequalities with additional state constraints. We present a relaxed formulation for the problem. With penalization methods and approximation techniques we give qualification conditions to get first-order optimality conditions. 1. Introduction. In this paper we(More)
We consider an optimal control problem where the state satisfies a bilateral elliptic varia-tional inequality and the control functions are the upper and lower obstacles. We seek a state that is close to a desired profile and the H 2 norms of the obstacles are not too large. Existence results are given and an optimality system is derived. A particular case(More)
The aim of this paper is to construct a model which decomposes a 3D image into two components: the first one containing the geometrical structure of the image, the second one containing the noise. The proposed method is based on a second order variational model and an undecimated wavelet thresholding operator. The numerical implementation is described, and(More)