Search for dissertations about: "Variational problems"

Showing result 1 - 5 of 47 swedish dissertations containing the words Variational problems.

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

    University dissertation from Umeå : Datavetenskap

    Author : Claude Lacoursière; Umeå universitet.; [2007]
    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; NATURAL SCIENCES Physics Other physics Computational physics; NATURVETENSKAP Fysik Övrig fysik 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

  2. 2. Variational Problems and Level Set Methods in Computer Vision - Theory and Applications

    University dissertation from Mathematics (Faculty of Technology)

    Author : Jan Erik Solem; Lund University.; Lunds universitet.; [2006]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; level set methods; computer vision; variational problems; Matematik;

    Abstract : Current state of the art suggests the use of variational formulations for solving a variety of computer vision problems. This thesis deals with such variational problems which often include the optimization of curves and surfaces. READ MORE

  3. 3. Variational Methods in Combinatorial Optimization and Phylogeny Reconstruction

    University dissertation from Department of Theoretical Physics, Lund University

    Author : Henrik Jönsson; Lund University.; Lunds universitet.; [2001]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; statistical physics; gravitation; relativity; annealing; variational; mean-field; phylogeny; constraint satisfaction; combinatorial optimization; maximum likelihood; Physics; Fysik; Mathematical and general theoretical physics; quantum mechanics; classical mechanics; klassisk mekanik; kvantmekanik; relativitet; statistisk fysik; termodynamik; Fysicumarkivet A:2001:Jönsson; Matematisk och allmän teoretisk fysik; thermodynamics;

    Abstract : Algorithms based on the variational approach, as used in statistical physics, are developed. For constraint satisfaction problems a novel cost function, based on information-theoretic arguments, is introduced, and an algorithm similar to the mean-field annealing algorithm is proposed. READ MORE

  4. 4. Multidimensional inverse problems in imaging and identification using low-complexity models, optimal mass transport, and machine learning

    University dissertation from Stockholm, Sweden : KTH Royal Institute of Technology

    Author : Axel Ringh; KTH.; [2018]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Inverse problems; convex optimization; variational regularization; trigonometric moment problems; optimal mass transport; computed tomography; machine learning; analytic interpolation; delay systems; Inversa problem; konvex optimering; variationell regularisering; trigonometriska momentproblem; optimal masstransport; datortomografi; maskininlärning; analytisk interpolation; system med tidsfördröjning; Matematik; Mathematics;

    Abstract : This thesis, which mainly consists of six appended papers, primarily considers a number of inverse problems in imaging and system identification.In particular, the first two papers generalize results for the rational covariance extension problem from one to higher dimensions. READ MORE

  5. 5. Adaptive variational multiscale methods

    University dissertation from Göteborg : Chalmers University of Technology

    Author : Axel Målqvist; Göteborgs universitet.; Gothenburg University.; [2005]
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; finite element method; Galerkin; duality; a posteriori error estimation; adaptivity; variational multiscale method; mixed formulation; multi-physics; oil reservoir simulation;

    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