Browsing Past Topics (PT) by Issue Date
Now showing items 2140 of 220

Localized solutions for the finite difference semidiscretization of the wave equation [Solutions localisées pour la semidiscrétisation par différences finies de l'équation des ondes]
(20101231)We study the propagation properties of the solutions of the finite difference space semidiscrete wave equation on a uniform grid of the whole Euclidean space. We provide a construction of high frequency wave packets that ... 
Localized solutions and filtering mechanisms for the discontinuous Galerkin semidiscretizations of the 1d wave equation [Solutions localisées et mécanismes de filtrage pour les approximations de Galerkin discontinues de l'équation des ondes.]
(20101231)We perform a complete Fourier analysis of the semidiscrete 1d wave equation obtained through a P1 discontinuous Galerkin (DG) approximation of the continuous wave equation on an uniform grid. The resulting system exhibits ... 
Optimal control and vanishing viscosity for the burgers equation
(20101231)[No abstract available] 
Exact Controllability of the Time Discrete Wave Equation: A Multiplier Approach
(20101231)In this paper we summarize our recent results on the exact boundary controllability of a trapezoidal time discrete wave equation in a bounded domain. It is shown that the projection of the solution in an appropriate space ... 
Asymptotic limits and stabilization for the 1D nonlinear MindlinTimoshenko system
(20101231)This paper shows how the so called von Kármán model can be obtained as a singular limit of a modified MindlinTimoshenko system when the modulus of elasticity in shear k tends to infinity, provided a regularizing term ... 
The Hardy inequality and the heat equation in twisted tubes
(20101231)We show that a twist of a threedimensional tube of uniform crosssection yields an improved decay rate for the heat semigroup associated with the Dirichlet Laplacian in the tube. The proof employs Hardy inequalities for ... 
Asymptotics and stabilization for dynamic models of nonlinear beams
(20101231)We prove that the von Kármán model for vibrating beams can be obtained as a singular limit of a modified MindlinTimoshenko system when the modulus of elasticity in shear k tends to infinity, provided a regularizing term ... 
Numerical approximation of null controls for the heat equation : Illposedness and remedies
(20101231)The numerical approximation of exact or trajectory controls for the wave equation is known to be a delicate issue, since the pioneering work of GlowinskiLions in the nineties, because of the anomalous behavior of the ... 
On the regularity of nullcontrols of the linear 1d heat equation [Sur la regularité des contrôles pour l'équation de la chaleur linéaire]
(20111231)The 1d heat equation in a bounded interval is nullcontrollable from the boundary. More precisely, for each initial data y0εL2(0,1) there corresponds a unique boundary control of minimal L2(0,T)norm which drives the state ... 
Fine structure of spectral properties for random correlation matrices: An application to financial markets
(20111231)We study some properties of eigenvalue spectra of financial correlation matrices. In particular, we investigate the nature of the large eigenvalue bulks which are observed empirically, and which have often been regarded ... 
Solutions to a model with Neumann boundary conditions for phase transitions driven by configurational forces
(20111231)We study an initial boundary value problem of a model describing the evolution in time of diffusive phase interfaces in solid materials, in which martensitic phase transformations driven by configurational forces take ... 
Observability of heat processes by transmutation without geometric restrictions
(20111231)The goal of this note is to explain how transmutation techniques (originally introduced in [14] in the context of the control of the heat equation, inspired on the classical Kannai transform, and recently revisited in [4] ... 
Hardy inequality and Pohozaev identity for operators with boundary singularities: Some applications
(20111231)We consider the Schrödinger operator Aλ:=δλ/x2, λ∈R, when the singularity is located on the boundary of a smooth domain Ω⊂RN, N≥1.The aim of this Note is two folded. Firstly, we justify the extension of the classical ... 
Large Time Asymptotics for Partially Dissipative Hyperbolic Systems
(20111231)This work is concerned with (ncomponent) hyperbolic systems of balance laws in m space dimensions. First, we consider linear systems with constant coefficients and analyze the possible behavior of solutions as t → ∞. Using ... 
Dispersive Properties for Discrete Schrödinger Equations
(20111231)In this paper we prove dispersive estimates for the system formed by two coupled discrete Schrödinger equations. We obtain estimates for the resolvent of the discrete operator and prove that it satisfies the limiting ... 
Solvability via viscosity solutions for a model of phase transitions driven by configurational forces
(20111231)This article is concerned with an initialboundary value problem for an ellipticparabolic coupled system arising in martensitic phase transition theory of elastically deformable solid materials, e.g., steel. This model ... 
The asymptotic behaviour of the heat equation in a twisted DirichletNeumann waveguide
(20111231)We consider the heat equation in a straight strip, subject to a combination of Dirichlet and Neumann boundary conditions. We show that a switch of the respective boundary conditions leads to an improvement of the decay ... 
Stationary policies for the second moment stability in a class of stochastic systems
(20111231)This paper presents a study on the uniform second moment stability for a class of stochastic control system. The main result states that the existence of the longrun average cost under a stationary policy is equivalent ... 
Emerging properties of financial time series in the "game of Life"
(20111231)We explore the spatial complexity of Conway's "Game of Life," a prototypical cellular automaton by means of a geometrical procedure generating a twodimensional random walk from a bidimensional lattice with periodical ... 
Counterexamples of regularity behavior for σevolution equations
(20111231)In this paper, we mainly discuss the infinite loss of regularity and μloss for a σevolution type model with oscillating in time coefficients. On the one hand, an explicit counterexample has been constructed in the ...