Unicité des lois optimales du contrôle stochastique continu dans le cas complètement observable
Unicité et contrôle pour le système de Lamé
Dans cet article on étudie le problème de l’unicité locale pour le système de Lamé. On prouve qu’on a l’unicité de Cauchy par rapport à toute surface non caractéristique. Nous donnons également deux résultats de densité qui s’applique à la théorie du contrôle pour le système de Lamé.
Unicité et contrôle pour le système de Lamé
In this paper, we study the uniqueness problem for the Lamé system. We prove that we have the uniqueness property across any non characteristic surface. We also give two results which apply to the boundary controllability for the Lamé system.
Uniform controllability for Kirchhoff and Mindlin-Timoshenko elastic systems.
Uniform controllability for the beam equation with vanishing structural damping
This paper is devoted to studying the effects of a vanishing structural damping on the controllability properties of the one dimensional linear beam equation. The vanishing term depends on a small parameter . We study the boundary controllability properties of this perturbed equation and the behavior of its boundary controls as goes to zero. It is shown that for any time sufficiently large but independent of and for each initial data in a suitable space there exists a uniformly bounded...
Uniform controllability of the linear one dimensional Schrödinger equation with vanishing viscosity
This article considers the linear 1-d Schrödinger equation in (0,π) perturbed by a vanishing viscosity term depending on a small parameter ε > 0. We study the boundary controllability properties of this perturbed equation and the behavior of its boundary controls vε as ε goes to zero. It is shown that, for any time T sufficiently large but independent of ε and for each initial datum in H−1(0,π), there exists a uniformly...
Uniform controllability of the linear one dimensional Schrödinger equation with vanishing viscosity
This article considers the linear 1-d Schrödinger equation in (0,π) perturbed by a vanishing viscosity term depending on a small parameter ε > 0. We study the boundary controllability properties of this perturbed equation and the behavior of its boundary controls vε as ε goes to zero. It is shown that, for any time T sufficiently large but independent of ε and for each initial datum in H−1(0,π), there exists a uniformly...
Uniform energy decay rates of hyperbolic equations with nonlinear boundary and interior dissipation
Uniform exponential energy decay of Euler-Bernoulli equations by suitable boundary feedback operators
We study the uniform stabilization problem for the Euler-Bernoulli equation defined on a smooth bounded domain of any dimension with feedback dissipative operators in various boundary conditions.
Uniform exponential stability for linear discrete time systems with stochastic perturbations in Hilbert spaces
In this paper we study the exponential and uniform exponential stability problem for linear discrete time-varying systems with independent stochastic perturbations. We give two representations of the solutions of the discussed systems and we use them to obtain necessary and sufficient conditions for the two types of stability. A deterministic characterization of the uniform exponential stability, in terms of Lyapunov equations are given.
Uniform local null control of the Leray-α model
This paper deals with the distributed and boundary controllability of the so called Leray-α model. This is a regularized variant of the Navier−Stokes system (α is a small positive parameter) that can also be viewed as a model for turbulent flows. We prove that the Leray-α equations are locally null controllable, with controls bounded independently of α. We also prove that, if the initial data are sufficiently small, the controls converge as α → 0+ to a null control of the Navier−Stokes equations....
Uniform null-controllability for the one-dimensional heat equation with rapidly oscillating periodic density
Uniform stability of displacement coupled second-order equations.
Uniform stabilization and exact control of multilayered piezoelectric body.
Uniform stabilization and exact controllability for hyperbolic systems with discontinuous coefficients.
Uniform stabilization for the Timoshenko beam by a locally distributed damping.
Uniform stabilization of a coupled structural acoustic system by boundary dissipation.
Uniform stabilization of some damped second order evolution equations with vanishing short memory
We consider a damped abstract second order evolution equation with an additional vanishing damping of Kelvin–Voigt type. Unlike the earlier work by Zuazua and Ervedoza, we do not assume the operator defining the main damping to be bounded. First, using a constructive frequency domain method coupled with a decomposition of frequencies and the introduction of a new variable, we show that if the limit system is exponentially stable, then this evolutionary system is uniformly − with respect to the calibration...
Uniformly exponentially stable approximations for a class of second order evolution equations
We consider the approximation of a class of exponentially stable infinite dimensional linear systems modelling the damped vibrations of one dimensional vibrating systems or of square plates. It is by now well known that the approximating systems obtained by usual finite element or finite difference are not, in general, uniformly stable with respect to the discretization parameter. Our main result shows that, by adding a suitable numerical viscosity term in the numerical scheme, our approximations are...
Unifying approach to observer-filter design
The paper examines similarities between observer design as introduced in Automatic Control Theory and filter design as established in Signal Processing. It is shown in the paper that there are obvious connections between them in spite of different aims for their design. Therefore, it is prospective to make them be compatible from the structural point of view. Introduced error invariance and error convergence properties of both of them are unifying tools for their design. Lyapunov's stability theory,...