Sökning: "variational problems"

Visar resultat 1 - 5 av 64 avhandlingar innehållade orden variational problems.

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

    Författare :Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

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

    Författare :Jan Erik Solem; Matematik LTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; level set methods; computer vision; variational problems; Matematik;

    Sammanfattning : 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. LÄS MER

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

    Författare :Henrik Jönsson; Beräkningsbiologi och biologisk fysik - Genomgår omorganisation; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

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

    Författare :Axel Ringh; Johan Karlsson; Rodolphe Sepulchre; KTH; []
    Nyckelord :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; Mathematics; Matematik;

    Sammanfattning : 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. LÄS MER

  7. 5. Adaptive variational multiscale methods

    Författare :Axel Målqvist; Göteborgs universitet; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER