Displaying similar documents to “Nouvelles formulations intégrales pour les problèmes de diffraction d'ondes”

Stabilisation frontière de problèmes de Ventcel

Amar Heminna (2010)

ESAIM: Control, Optimisation and Calculus of Variations

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The problem of boundary stabilization for the isotropic linear elastodynamic system and the wave equation with Ventcel's conditions are considered (see [12]). The boundary observability and the exact controllability were etablished in [11]. We prove here the enegy decay to zero for the elastodynamic system with stationary Ventcel's conditions by introducing a nonlinear boundary feedback. We also give a boundary feedback leading to arbitrarily large energy decay rates for the elastodynamic...

Remarques sur l'observabilité pour l'équation de Laplace

Kim-Dang Phung (2010)

ESAIM: Control, Optimisation and Calculus of Variations

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We consider the Laplace equation in a smooth bounded domain. We prove logarithmic estimates, in the sense of John [5] of solutions on a part of the boundary or of the domain without known boundary conditions. These results are established by employing Carleman estimates and techniques that we borrow from the works of Robbiano [8,11]. Also, we establish an estimate on the cost of an approximate control for an elliptic model equation.

Sur des inégalités intégrales et applications à la stabilité de quelques systèmes distribués non dissipatifs

Aïssa Guesmia

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First we prove some new integral inequalities to obtain a precise estimate on behavior at infinity of a positive and not necessarily decreasing functon. This extends in many directions and improves in certain cases some integral inequalities due to A. Haraux, V. Komornik, P. Martinez, M. Eller et al. and F. Alabau-Boussouira concerning decreasing functions. Then we give applications to (internal or boundary, linear or nonlinear) stabilization of certain nondissipative distributed...

Sur les paires d'équations pré-Schröder et leur équivalence

Józef Kalinowski (2004)

Annales Polonici Mathematici

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Pairs of functional pre-Schröder equations (Sₙ) are considered. We show that under some assumptions the system of two equations (S₃), (Sₙ) for some n ≥ 4 is equivalent to the system of all equations (Sₙ) for n ≥ 2. The results answer a question of Gy. Targonski [5] in a particular case.