On unique solvability of the periodic problem in the plane for linear hyperbolic equations.
On uniqueness and existence of entropy solutions of weakly coupled systems of nonlinear degenerate parabolic equations.
On volumetric growth and material frames.
On weak solution to a hyperbolic differential inclusion with nonmonotone discontinuous nonlinear term.
On weak solutions of semilinear hyperbolic-parabolic equations.
Ondes de raréfaction pour des systèmes quasilinéaires hyperboliques multidimensionnels
Ondes hyperboliques non linéaires globales
Ondes lentes et interaction contrôlée pour les équations strictement hyperboliques non linéaires
Ondes oscillantes semi-linéaires en 1.d
Ondes oscillantes simples quasilinéaires
Ondes soniques
One-dimensional adhesion model for large scale structures.
Opérateurs hyperboliques à caractéristiques de multiplicité constante
Soit un opérateur hyperbolique à caractéristiques de multiplicité constante. On sait que le problème de Cauchy est mal posé si on n’impose pas une condition, dite de Lévi, sur les termes d’ordre inférieur. On démontre que cette condition implique la possibilité de construire une paramétrix du problème de Cauchy au moyen des opérateurs intégraux de Fourier. On en déduit la résolubilité du problème de Cauchy dans les fonctions et dans les espaces de Sobolev.
Operational Methods in the Environment of a Computer Algebra System
This article presents the principal results of the doctoral thesis “Direct Operational Methods in the Environment of a Computer Algebra System” by Margarita Spiridonova (Institute of mathematics and Informatics, BAS), successfully defended before the Specialised Academic Council for Informatics and Mathematical Modelling on 23 March, 2009.The presented research is related to the operational calculus approach and its representative applications. Operational methods are considered, as well as their...
Optical leptons.
Optimal blowup rates for the minimal energy null control of the strongly damped abstract wave equation
The null controllability problem for a structurally damped abstract wave equation –often referred to in the literature as a structurally damped equation– is considered with a view towards obtaining optimal rates of blowup for the associated minimal energy function , as terminal time . Key use is made of the underlying analyticity of the semigroup generated by the elastic operator , as well as of the explicit characterization of its domain of definition. We ultimately find that the blowup rate...
Optimal control of a rotating body beam
In this paper we consider the problem of optimal control of the model for a rotating body beam, which describes the dynamics of motion of a beam attached perpendicularly to the center of a rigid cylinder and rotating with the cylinder. The control is applied on the cylinder via a torque to suppress the vibrations of the beam. We prove that there exists at least one optimal control and derive a necessary condition for the control. Furthermore, on the basis of iteration method, we propose numerical...
Optimal Control of a Rotating Body Beam
In this paper we consider the problem of optimal control of the model for a rotating body beam, which describes the dynamics of motion of a beam attached perpendicularly to the center of a rigid cylinder and rotating with the cylinder. The control is applied on the cylinder via a torque to suppress the vibrations of the beam. We prove that there exists at least one optimal control and derive a necessary condition for the control. Furthermore, on the basis of iteration method, we propose ...
Optimal control of nonlinear one-dimensional periodic wave equation with x-dependent coefficients
This paper is concerned with an optimal control problem governed by the nonlinear one dimensional periodic wave equation with x-dependent coefficients. The control of the system is realized via the outer function of the state. Such a model arises from the propagation of seismic waves in a nonisotropic medium. By investigating some important properties of the linear operator associated with the state equation, we obtain the existence and regularity of the weak solution to the state equation. Furthermore,...
Optimal control of systems determined by strongly nonlinear operator valued measures
In this paper we consider a class of distributed parameter systems (partial differential equations) determined by strongly nonlinear operator valued measures in the setting of the Gelfand triple V ↪ H ↪ V* with continuous and dense embeddings where H is a separable Hilbert space and V is a reflexive Banach space with dual V*. The system is given by dx + A(dt,x) = f(t,x)γ(dt) + B(t)u(dt), x(0) = ξ, t ∈ I ≡ [0,T] where A is a strongly nonlinear operator valued measure...