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All-at-once preconditioning in PDE-constrained optimization

Tyrone Rees, Martin Stoll, Andy Wathen (2010)

Kybernetika

The optimization of functions subject to partial differential equations (PDE) plays an important role in many areas of science and industry. In this paper we introduce the basic concepts of PDE-constrained optimization and show how the all-at-once approach will lead to linear systems in saddle point form. We will discuss implementation details and different boundary conditions. We then show how these system can be solved efficiently and discuss methods and preconditioners also in the case when bound...

Almost sure properties of controlled diffusions and worst case properties of deterministic systems

Martino Bardi, Annalisa Cesaroni (2008)

ESAIM: Control, Optimisation and Calculus of Variations

We compare a general controlled diffusion process with a deterministic system where a second controller drives the disturbance against the first controller. We show that the two models are equivalent with respect to two properties: the viability (or controlled invariance, or weak invariance) of closed smooth sets, and the existence of a smooth control Lyapunov function ensuring the stabilizability of the system at an equilibrium.


A-monotone nonlinear relaxed cocoercive variational inclusions

Ram Verma (2007)

Open Mathematics

Based on the notion of A - monotonicity, a new class of nonlinear variational inclusion problems is presented. Since A - monotonicity generalizes H - monotonicity (and in turn, generalizes maximal monotonicity), results thus obtained, are general in nature.

An a posteriori error analysis of adaptive finite element methods for distributed elliptic control problems with control constraints

Michael Kieweg, Yuri Iliash, Ronald H. W. Hoppe, Michael Hintermüller (2008)

ESAIM: Control, Optimisation and Calculus of Variations

We present an a posteriori error analysis of adaptive finite element approximations of distributed control problems for second order elliptic boundary value problems under bound constraints on the control. The error analysis is based on a residual-type a posteriori error estimator that consists of edge and element residuals. Since we do not assume any regularity of the data of the problem, the error analysis further invokes data oscillations. We prove reliability and efficiency of the error estimator...

An a posteriori error analysis of adaptive finite element methods for distributed elliptic control problems with control constraints

Michael Hintermüller, Ronald H.W. Hoppe, Yuri Iliash, Michael Kieweg (2007)

ESAIM: Control, Optimisation and Calculus of Variations

We present an a posteriori error analysis of adaptive finite element approximations of distributed control problems for second order elliptic boundary value problems under bound constraints on the control. The error analysis is based on a residual-type a posteriori error estimator that consists of edge and element residuals. Since we do not assume any regularity of the data of the problem, the error analysis further invokes data oscillations. We prove reliability and efficiency of the error estimator...

An a priori Campanato type regularity condition for local minimisers in the calculus of variations

Thomas J. Dodd (2010)

ESAIM: Control, Optimisation and Calculus of Variations

An a priori Campanato type regularity condition is established for a class of W1X local minimisers u ¯ of the general variational integral Ω F ( u ( x ) ) d x where Ω n is an open bounded domain, F is of class C2, F is strongly quasi-convex and satisfies the growth condition F ( ξ ) c ( 1 + | ξ | p ) for a p > 1 and where the corresponding Banach spaces X are the Morrey-Campanato space p , μ ( Ω , N × n ) , µ < n, Campanato space p , n ( Ω , N × n ) and the space of bounded mean oscillation BMO Ω , N × n ) . The admissible maps u : Ω N are of Sobolev class W1,p, satisfying a Dirichlet boundary...

An active set strategy based on the augmented Lagrangian formulation for image restoration

Kazufumi Ito, Karl Kunisch (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Lagrangian and augmented Lagrangian methods for nondifferentiable optimization problems that arise from the total bounded variation formulation of image restoration problems are analyzed. Conditional convergence of the Uzawa algorithm and unconditional convergence of the first order augmented Lagrangian schemes are discussed. A Newton type method based on an active set strategy defined by means of the dual variables is developed and analyzed. Numerical examples for blocky signals and images perturbed by...

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