Sökning: "Convergence"

Visar resultat 1 - 5 av 718 avhandlingar innehållade ordet Convergence.

  1. 1. Selected Topics in Homogenization

    Författare :Jens Persson; Anders Holmbom; Liselott Flodén; Marianne Olsson Lindberg; Mårten Gulliksson; Peter Wall; Mittuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; homogenization theory; H-convergence; two-scale convergence; very weak two-scale convergence; multiscale convergence; very weak multiscale convergence; evolution-multiscale convergence; very weak evolution-multiscale convergence; λ-scale convergence; non-periodic linear elliptic problems; evolution-multiscale linear parabolic problems; evolution-multiscale monotone parabolic problems; detection of scales of heterogeneity;

    Sammanfattning : The main focus of the present thesis is on the homogenization of some selected elliptic and parabolic problems. More precisely, we homogenize: non-periodic linear elliptic problems in two dimensions exhibiting a homothetic scaling property; two types of evolution-multiscale linear parabolic problems, one having two spatial and two temporal microscopic scales where the latter ones are given in terms of a two-parameter family, and one having two spatial and three temporal microscopic scales that are fixed power functions; and, finally, evolution-multiscale monotone parabolic problems with one spatial and an arbitrary number of temporal microscopic scales that are not restricted to be given in terms of power functions. LÄS MER

  2. 2. Sequential convergence for functions and operators

    Författare :Jeanette Silfver; Mårten Gulliksson; Anders Holmbom; Nils Svanstedt; Mittuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; homogenization; two-scale convergence; G-convergence; H-convergence; partial differential equations; functional analysis; heterogeneous media; MATHEMATICS; MATEMATIK;

    Sammanfattning : The mathematical discipline homogenization theory is closely related to convergence issues. In this thesis different types of convergence are studied and put in relation to each other. We consider the classical concepts of G- and H-convergence and compensated compactness. LÄS MER

  3. 3. Homogenization of Partial Differential Equations using Multiscale Convergence Methods

    Författare :Pernilla Johnsen; Liselott Flodén; Anders Holmbom; Marianne Olsson Lindberg; Jens Persson; Niklas Wellander; Mittuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; homogenization theory; two-scale convergence; multiscale convergence; very weak multiscale convergence; evolution multiscale convergence; very weak evolution multiscale convergence; linear parabolic problems; linear hyperbolic-parabolic problems;

    Sammanfattning : The focus of this thesis is the theory of periodic homogenization of partial differential equations and some applicable concepts of convergence. More precisely, we study parabolic problems exhibiting both spatial and temporal microscopic oscillations and a vanishing volumetric heat capacity type of coefficient. LÄS MER

  4. 4. Homogenization of Some Selected Elliptic and Parabolic Problems Employing Suitable Generalized Modes of Two-Scale Convergence

    Författare :Jens Persson; Anders Holmbom; Liselott Flodén; Marianne Lindberg; Mårten Gulliksson; Peter Wall; Mittuniversitetet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; H-convergence; G-convergence; homogenization; multiscale analysis; two-scale convergence; multiscale convergence; elliptic partial differential equations; parabolic partial differential equations; monotone operators; heterogeneous media; non-periodic media; Mathematical analysis; Analys;

    Sammanfattning : The present thesis is devoted to the homogenization of certain elliptic and parabolic partial differential equations by means of appropriate generalizations of the notion of two-scale convergence. Since homogenization is defined in terms of H-convergence, we desire to find the H-limits of sequences of periodic monotone parabolic operators with two spatial scales and an arbitrary number of temporal scales and the H-limits of sequences of two-dimensional possibly non-periodic linear elliptic operators by utilizing the theories for evolution-multiscale convergence and λ-scale convergence, respectively, which are generalizations of the classical two-scale convergence mode and custom-made to treat homogenization problems of the prescribed kinds. LÄS MER

  5. 5. The Dirac Operator; From Numerics to the Theory of G-convergence

    Författare :Hasan Almanasreh; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dirac operator; spuriousity; cubic Hermitian; stability parameter; G-convergence; ¡-convergence; spectral measure; quadratic form; stability parameter;

    Sammanfattning : We consider two main issues concerning the Dirac operator, the first is widely known as the appearance of spurious eigenvalues within the spectrum. The second is the study of the asymptotic behavior of the eigenvalues for a family of Dirac operators with oscillatory potential added to the Coulomb-Dirac Hamiltonian. LÄS MER