All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Page 1

Displaying 1 – 11 of 11

Showing per page

Mathematical Modeling of Atmospheric Flow and Computation of Convex Envelopes

A. Caboussat (2011)

Mathematical Modelling of Natural Phenomena

Atmospheric flow equations govern the time evolution of chemical concentrations in the atmosphere. When considering gas and particle phases, the underlying partial differential equations involve advection and diffusion operators, coagulation effects, and evaporation and condensation phenomena between the aerosol particles and the gas phase. Operator splitting techniques are generally used in global air quality models. When considering organic aerosol...

Mesh-independence and preconditioning for solving parabolic control problems with mixed control-state constraints

Michael Hintermüller, Ian Kopacka, Stefan Volkwein (2009)

ESAIM: Control, Optimisation and Calculus of Variations

Optimal control problems for the heat equation with pointwise bilateral control-state constraints are considered. A locally superlinearly convergent numerical solution algorithm is proposed and its mesh independence is established. Further, for the efficient numerical solution reduced space and Schur complement based preconditioners are proposed which take into account the active and inactive set structure of the problem. The paper ends by numerical tests illustrating our theoretical findings and...

Mesh-independence and preconditioning for solving parabolic control problems with mixed control-state constraints

Michael Hintermüller, Ian Kopacka, Stefan Volkwein (2008)

ESAIM: Control, Optimisation and Calculus of Variations

Optimal control problems for the heat equation with pointwise bilateral control-state constraints are considered. A locally superlinearly convergent numerical solution algorithm is proposed and its mesh independence is established. Further, for the efficient numerical solution reduced space and Schur complement based preconditioners are proposed which take into account the active and inactive set structure of the problem. The paper ends by numerical tests illustrating our theoretical findings and comparing...

Minimal invasion: An optimal L∞ state constraint problem

Christian Clason, Kazufumi Ito, Karl Kunisch (2011)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

In this work, the least pointwise upper and/or lower bounds on the state variable on a specified subdomain of a control system under piecewise constant control action are sought. This results in a non-smooth optimization problem in function spaces. Introducing a Moreau-Yosida regularization of the state constraints, the problem can be solved using a superlinearly convergent semi-smooth Newton method. Optimality conditions are derived, convergence of the Moreau-Yosida regularization is proved, and...

Minimal invasion: An optimal L∞ state constraint problem

Christian Clason, Kazufumi Ito, Karl Kunisch (2011)

ESAIM: Mathematical Modelling and Numerical Analysis

In this work, the least pointwise upper and/or lower bounds on the state variable on a specified subdomain of a control system under piecewise constant control action are sought. This results in a non-smooth optimization problem in function spaces. Introducing a Moreau-Yosida regularization of the state constraints, the problem can be solved using a superlinearly convergent semi-smooth Newton method. Optimality conditions are derived, convergence of the Moreau-Yosida regularization is proved, and...

Mixed formulations for a class of variational inequalities

Leila Slimane, Abderrahmane Bendali, Patrick Laborde (2004)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

A general setting is proposed for the mixed finite element approximations of elliptic differential problems involving a unilateral boundary condition. The treatment covers the Signorini problem as well as the unilateral contact problem with or without friction. Existence, uniqueness for both the continuous and the discrete problem as well as error estimates are established in a general framework. As an application, the approximation of the Signorini problem by the lowest order mixed finite element...

Mixed formulations for a class of variational inequalities

Leila Slimane, Abderrahmane Bendali, Patrick Laborde (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

A general setting is proposed for the mixed finite element approximations of elliptic differential problems involving a unilateral boundary condition. The treatment covers the Signorini problem as well as the unilateral contact problem with or without friction. Existence, uniqueness for both the continuous and the discrete problem as well as error estimates are established in a general framework. As an application, the approximation of the Signorini problem by the lowest order mixed finite element...

Modelling and control in pseudoplate problem with discontinuous thickness

Ján Lovíšek (2009)

Applications of Mathematics

This paper concerns an obstacle control problem for an elastic (homogeneous) and isotropic) pseudoplate. The state problem is modelled by a coercive variational inequality, where control variable enters the coefficients of the linear operator. Here, the role of control variable is played by the thickness of the pseudoplate which need not belong to the set of continuous functions. Since in general problems of control in coefficients have no optimal solution, a class of the extended optimal control...

Currently displaying 1 – 11 of 11

Page 1