Displaying 221 – 240 of 561

Showing per page

Homogenization of unbounded functionals and nonlinear elastomers. The case of the fixed constraints set

Luciano Carbone, Doina Cioranescu, Riccardo De Arcangelis, Antonio Gaudiello (2004)

ESAIM: Control, Optimisation and Calculus of Variations

The paper is a continuation of a previous work of the same authors dealing with homogenization processes for some energies of integral type arising in the modeling of rubber-like elastomers. The previous paper took into account the general case of the homogenization of energies in presence of pointwise oscillating constraints on the admissible deformations. In the present paper homogenization processes are treated in the particular case of fixed constraints set, in which minimal coerciveness hypotheses...

Homogenization of unbounded functionals and nonlinear elastomers. The case of the fixed constraints set

Luciano Carbone, Doina Cioranescu, Riccardo De Arcangelis, Antonio Gaudiello (2010)

ESAIM: Control, Optimisation and Calculus of Variations

The paper is a continuation of a previous work of the same authors dealing with homogenization processes for some energies of integral type arising in the modeling of rubber-like elastomers. The previous paper took into account the general case of the homogenization of energies in presence of pointwise oscillating constraints on the admissible deformations. In the present paper homogenization processes are treated in the particular case of fixed constraints set, in which minimal coerciveness hypotheses...

Homogenization of variational problems in manifold valued Sobolev spaces

Jean-François Babadjian, Vincent Millot (2010)

ESAIM: Control, Optimisation and Calculus of Variations

Homogenization of integral functionals is studied under the constraint that admissible maps have to take their values into a given smooth manifold. The notion of tangential homogenization is defined by analogy with the tangential quasiconvexity introduced by Dacorogna et al. [Calc. Var. Part. Diff. Eq. 9 (1999) 185–206]. For energies with superlinear or linear growth, a Γ-convergence result is established in Sobolev spaces, the homogenization problem in the space of functions of bounded variation...

How to state necessary optimality conditions for control problems with deviating arguments?

Lassana Samassi, Rabah Tahraoui (2008)

ESAIM: Control, Optimisation and Calculus of Variations

The aim of this paper is to give a general idea to state optimality conditions of control problems in the following form: inf ( u , v ) 𝒰 a d 0 1 f t , u ( θ v ( t ) ) , u ' ( t ) , v ( t ) d t , (1) where 𝒰 a d is a set of admissible controls and θ v is the solution of the following equation: { d θ ( t ) d t = g ( t , θ ( t ) , v ( t ) ) , t [ 0 , 1 ] ; θ ( 0 ) = θ 0 , θ ( t ) [ 0 , 1 ] t . (2). The results are nonlocal and new.

Image segmentation with a finite element method

Blaise Bourdin (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

The Mumford-Shah functional for image segmentation is an original approach of the image segmentation problem, based on a minimal energy criterion. Its minimization can be seen as a free discontinuity problem and is based on Γ-convergence and bounded variation functions theories. Some new regularization results, make possible to imagine a finite element resolution method. In a first time, the Mumford-Shah functional is introduced and some existing results are quoted. Then, a discrete formulation...

Integral representation and relaxation for Junctionals defined on measures

Ennio De Giorgi, Luigi Ambrosio, Giuseppe Buttazzo (1987)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Given a separable metric locally compact space Ω , and a positive finite non-atomic measure λ on Ω , we study the integral representation on the space of measures with bounded variation Ω of the lower semicontinuous envelope of the functional F ( u ) = Ω f ( x , y ) d λ    u L 1 ( Ω , λ , n ) with respect to the weak convergence of measures.

Integral representation and Γ -convergence of variational integrals with p ( x ) -growth

Alessandra Coscia, Domenico Mucci (2002)

ESAIM: Control, Optimisation and Calculus of Variations

We study the integral representation properties of limits of sequences of integral functionals like f ( x , D u ) d x under nonstandard growth conditions of ( p , q ) -type: namely, we assume that | z | p ( x ) f ( x , z ) L ( 1 + | z | p ( x ) ) . Under weak assumptions on the continuous function p ( x ) , we prove Γ -convergence to integral functionals of the same type. We also analyse the case of integrands f ( x , u , D u ) depending explicitly on u ; finally we weaken the assumption allowing p ( x ) to be discontinuous on nice sets.

Integral representation and Γ-convergence of variational integrals with p(x)-growth

Alessandra Coscia, Domenico Mucci (2010)

ESAIM: Control, Optimisation and Calculus of Variations

We study the integral representation properties of limits of sequences of integral functionals like   f ( x , D u ) d x   under nonstandard growth conditions of (p,q)-type: namely, we assume that | z | p ( x ) f ( x , z ) L ( 1 + | z | p ( x ) ) . Under weak assumptions on the continuous function p(x), we prove Γ-convergence to integral functionals of the same type. We also analyse the case of integrands f(x,u,Du) depending explicitly on u; finally we weaken the assumption allowing p(x) to be discontinuous on nice sets.

Integrals with respect to a Radon measure added to area type functionals: semi-continuity and relaxation

Michele Carriero, Antonio Leaci, Eduardo Pascali (1985)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

Diamo condizioni sulle funzioni f , g e sulla misura μ affinché il funzionale F ( u ) = Ω f ( x , u , D u ) d x + Ω ¯ g ( x , u ) d μ sia L 1 ( Ω ) -semicontinuo inferiormente su W 1 , 1 ( Ω ) C 0 ( Ω ¯ ) . Affrontiamo successivamente il problema del rilassamento.

Currently displaying 221 – 240 of 561