Displaying similar documents to “Stabilisation frontière de problèmes de Ventcel”

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.

Nouvelles formulations intégrales pour les problèmes de diffraction d'ondes

David P. Levadoux, Bastiaan L. Michielsen (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

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We present an integral equation method for solving boundary value problems of the Helmholtz equation in unbounded domains. The method relies on the factorisation of one of the Calderón projectors by an operator approximating the exterior admittance (Dirichlet to Neumann) operator of the scattering obstacle. We show how the pseudo-differential calculus allows us to construct such approximations and that this yields integral equations without internal resonances and being well-conditioned at...

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.

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...

Vortex motion and phase-vortex interaction in dissipative Ginzburg-Landau dynamics

F. Bethuel, G. Orlandi, D. Smets (2004)

Journées Équations aux dérivées partielles

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We discuss the asymptotics of the parabolic Ginzburg-Landau equation in dimension N 2 . Our only asumption on the initial datum is a natural energy bound. Compared to the case of “well-prepared” initial datum, this induces possible new energy modes which we analyze, and in particular their mutual interaction. The two dimensional case is qualitatively different and requires a separate treatment.

Un algorithme d'identification de frontières soumises à des conditions aux limites de Signorini

Slim Chaabane, Mohamed Jaoua (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

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This work deals with a non linear inverse problem of reconstructing an unknown boundary , the boundary conditions prescribed on being of Signorini type, by using boundary measurements. The problem is turned into an optimal shape design one, by constructing a Kohn & Vogelius-like cost function, the only minimum of which is proved to be the unknown boundary. Furthermore, we prove that the derivative of this cost function with respect to a direction depends only on the state ...