Sökning: "Petrov-Galerkin"

Visar resultat 1 - 5 av 11 avhandlingar innehållade ordet Petrov-Galerkin.

  1. 1. Multiscale Methods and Uncertainty Quantification

    Författare :Daniel Elfverson; Axel Målqvist; Frédéric Legoll; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; multiscale methods; finite element method; discontinuous Galerkin; Petrov-Galerkin; a priori; a posteriori; complex geometry; uncertainty quantification; multilevel Monte Carlo; failure probability; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : In this thesis we consider two great challenges in computer simulations of partial differential equations: multiscale data, varying over multiple scales in space and time, and data uncertainty, due to lack of or inexact measurements.We develop a multiscale method based on a coarse scale correction, using localized fine scale computations. LÄS MER

  3. 2. A weak space-time formulation for the linear stochastic heat equation

    Författare :Matteo Molteni; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Inf-sup theory; Stochastic heat equation; Petrov-Galerkin; Finite element; Crank-Nicolson; Quasi-optimality; Finite element;

    Sammanfattning : The topic covered in this thesis is the introduction of a new formulation for the linear stochastic heat equation driven by additive noise, based on the space-time variational formulation for its deterministic counterpart. Having a variational formulation allows the use of the so called inf-sup theory in order to obtain results of existence and uniqueness in a relatively simple way. LÄS MER

  4. 3. The Dirac Equation: Numerical and Asymptotic Analysis

    Författare :Hasan Almanasreh; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dirac operator; eigenvalue problem; finite element method; spurious eigenvalues; Petrov-Galerkin; cubic Hermite basis functions; stability parameter; meshfree method; $hp$-cloud; intrinsic enrichment; G-convergence; $ Gamma$-convergence; scattering theory; identification; wave operator; stationary approach; Dirac operator;

    Sammanfattning : The thesis consists of three parts, although each part belongs to a specific subject area in mathematics, they are considered as subfields of the perturbation theory. The main objective of the presented work is the study of the Dirac operator; the first part concerns the treatment of the spurious eigenvalues in the computation of the discrete spectrum. LÄS MER

  5. 4. Variational Methods for Moments of Solutions to Stochastic Differential Equations

    Författare :Kristin Kirchner; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Additive and multiplicative noise; Stochastic partial differential equation; Projective and injective tensor product space; Hilbert tensor product space; Space-time variational problem; Petrov-Galerkin discretization; Stochastic ordinary differential equation;

    Sammanfattning : Numerical methods for stochastic differential equations typically estimate moments of the solution from sampled paths. Instead, we pursue the approach proposed by A. Lang, S. Larsson, and Ch. LÄS MER

  7. 5. Numerical Approximation of Solutions to Stochastic Partial Differential Equations and Their Moments

    Författare :Kristin Kirchner; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Petrov– Galerkin discretizations; Strong and weak convergence; Fractional operators; Finite element methods; Space-time variational problems; Tensor product spaces; Stochastic partial differential equations; White noise; Petrov– Galerkin discretizations;

    Sammanfattning : The first part of this thesis focusses on the numerical approximation of the first two moments of solutions to parabolic stochastic partial differential equations (SPDEs) with additive or multiplicative noise. More precisely, in Paper I an earlier result (A. Lang, S. Larsson, and Ch. LÄS MER