Search for dissertations about: "variational method"

Showing result 1 - 5 of 83 swedish dissertations containing the words variational method.

  2. 1. Adaptive variational multiscale methods

    Author : Axel Målqvist; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; finite element method; Galerkin; duality; a posteriori error estimation; adaptivity; variational multiscale method; mixed formulation; multi-physics; oil reservoir simulation; finite element method;

    Abstract : In this thesis we present a new adaptive multiscale method for solving elliptic partial differential equations. The method is based on numerical solution of decoupled local fine scale problems on patches. READ MORE

  4. 2. Adaptive Finite Element Methods for Optimal Control Problems

    Author : Karin Kraft; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; dual weighted residual; adaptive; Newton method; variational inequality; vehicle dynamics.; multilevel algorithm; discontinuous Galerkin method; a posteriori error estimate; finite element method; optimal control; control constraint;

    Abstract : In this thesis we study the numerical solution of optimal control problems. The problems considered consist of a systemof differential equations, the state equations, which are governed bya control variable. The goal is to determine the states and controls which minimize a given cost functional. READ MORE

  5. 3. Adaptive Finite Element Methods for Optimal Control Problems

    Author : Karin Kraft; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; finite element method; discontinuous Galerkin method; optimal control; a posteriori error estimate; dual weighted residual; adaptive; multilevel algorithm; Newton method; control constraint; variational inequality; vehicle dynamics.;

    Abstract : In this thesis we study the numerical solution of optimal control problems. The problems considered consist of a system of differential equations, the state equations, which are governed by a control variable. The goal is to determine the states and controls which minimize a given cost functional. READ MORE

  6. 4. Some Applications of Variational Inequalities in Mathematical Finance and Numerics

    Author : Martin Dahlgren; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Matematik; Mathematics; HJB quasi variational inequalities; option pricing; Impulse control; parabolic PDE; finite element method; Galerkin method;

    Abstract : This thesis contains two parts. The first part deals with a stochastic impulse control problem, subject to the restriction of a minimum time lapse in between interventions made by the controller. We prove existence of an optimal control and show that the value function of the control problem satisfies a system of quasi-variational inequalities. READ MORE

  7. 5. Ghosts and machines : regularized variational methods for interactive simulations of multibodies with dry frictional contacts

    Author : Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Discrete mechanics; Variational method; Contact problems; Impacts; Least action principle; Saddle point problems; Lagrange Multipliers; Constrained systems; Multibody Systems; Numerical regularization; Constraint realization; Constraint stabilization; Dry friction; Differential Algebraic Equations; Nonsmooth problems; Linear Complementarity; Quaternion algebra; Numerical linear algebra; Physics modeling; Interactive simulation; Numerical stability; Rigid body dynamics; Dissipative systems; Computational physics; Beräkningsfysik;

    Abstract : A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. READ MORE