A. Auslender, Optimisation : Méthodes numériques, 1976.

M. J. Balas, Active control of flexible systems, Journal of Optimization Theory and Applications, vol.18, issue.3, pp.415-436, 1978.
DOI : 10.1007/BF00932903

C. Bardos, G. Lebeau, and J. Rauch, Sharp Sufficient Conditions for the Observation, Control, and Stabilization of Waves from the Boundary, SIAM Journal on Control and Optimization, vol.30, issue.5, pp.1024-1065, 1992.
DOI : 10.1137/0330055

E. Bednarzuk, M. Pierre, E. Rouy, and J. Sokolowski, Tangent sets in some functional spaces, Nonlinear Anal, pp.871-876, 2000.

C. Castro and S. Cox, Achieving Arbitrarily Large Decay in the Damped Wave Equation, SIAM Journal on Control and Optimization, vol.39, issue.6, pp.1748-1755, 2001.
DOI : 10.1137/S0363012900370971

G. Chen, S. A. Fulling, F. J. Narcowich, and S. Sun, Exponential Decay of Energy of Evolution Equations with Locally Distributed Damping, SIAM Journal on Applied Mathematics, vol.51, issue.1, pp.266-301, 1991.
DOI : 10.1137/0151015

R. Cominetti and J. P. Penot, Tangent sets to unilateral convex sets, C. R. Acad. Sci. Paris Sr. I Math, issue.321 12, pp.1631-1636, 1995.

S. Cox and M. Overton, Perturbing the Critically Damped Wave Equation, SIAM Journal on Applied Mathematics, vol.56, issue.5, pp.1353-1362, 1996.
DOI : 10.1137/S0036139994277403

S. Cox and E. Zuazua, The rate at which energy decays in a damped string, Comm. in partial differential equations, pp.213-243, 1994.

G. and D. Maso, An introduction to ?-convergence, 1993.

P. Freitas, Optimizing the Rate of Decay of Solutions of the Wave Equation Using Genetic Algorithms: A Counterexample to the Constant Damping Conjecture, SIAM Journal on Control and Optimization, vol.37, issue.2, pp.376-387, 1999.
DOI : 10.1137/S0363012997329445

P. Freitas, On Some Eigenvalue Problems Related to the Wave Equation with Indefinite Damping, Journal of Differential Equations, vol.127, issue.1, pp.320-335, 1996.
DOI : 10.1006/jdeq.1996.0072

P. Freitas and E. Zuazua, Stability Results for the Wave Equation with Indefinite Damping, Journal of Differential Equations, vol.132, issue.2, pp.338-352, 1996.
DOI : 10.1006/jdeq.1996.0183

P. Hébrard and A. Henrot, Optimal shape and position of the actuators for the stabilization of a string, Systems & Control Letters, vol.48, issue.3-4, pp.199-209, 2003.
DOI : 10.1016/S0167-6911(02)00265-7

A. Henrot and M. Pierre, Variations et Optimisation de formes
DOI : 10.1007/3-540-37689-5

J. B. Hiriart-urruty and C. Lemaréchal, Convex analysis and minimization algorithms Algebraic and geometric methods in mathematical physics Math, Phys. Stud, vol.19, pp.73-109, 1993.

T. J. Mahar and B. E. Willner, Sturm-Liouville eigenvalue problems in which the squares of the eigenfunctions are linearly dependent Comm, Pure Appl. Math, issue.33 4, pp.567-578, 1980.

A. M. Micheletti, Perturbazione dello spettro dell'operatore di Laplace, in relazione ad una variazione del campo, Ann. Scuola Norm. Sup. Pisa, vol.26, issue.3, pp.151-169, 1972.

J. Ortega and E. Zuazua, Generic simplicity of the spectrum and stabilization for a plate model, SIAM J. Cont. Optim, issue.395, pp.1585-1614, 2001.

J. Ortega and E. Zuazua, On a Constrained Approximate Controllability Problem for the Heat Equation, Journal of Optimization Theory and Applications, vol.76, issue.1, pp.29-64, 2001.
DOI : 10.1023/A:1026409821088

L. R. Tcheugoue and E. Zuazua, Uniform exponential long time decay for the space semidiscretizations of a damped wave equation with artificial numerical viscosity, pp.563-598, 2003.

L. R. Tcheugoue and E. Zuazua, Uniform boundary stabilization of the finite difference space discretization of the 1 ? d wave equation, Advances in Computational Mathematics

L. N. Trefethen, Group velocity in finite difference schemes SIAM Rev, pp.113-136, 1982.

E. Zuazua, Propagation, observation, and control of waves approximated by finite difference methods SIAM Review