Sökning: "partial differential equations"

Visar resultat 21 - 25 av 230 avhandlingar innehållade orden partial differential equations.

  1. 21. Approximation of Optimally Controlled Ordinary and Partial Differential Equations

    Författare :Mattias Sandberg; Anders Szepessy; Nils-Henrik Risebro; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MATHEMATICS; MATEMATIK;

    Sammanfattning : In this thesis, which consists of four papers, approximation of optimal control problems is studied. In Paper I the Symplectic Pontryagin method for approximation of optimally controlled ordinary differential equations is presented. LÄS MER

  3. 22. Homogenization of some linear and nonlinear partial differential equations

    Författare :Niklas Wellander; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : In this thesis is studied two-scale convergence for sequences of linear and nonlinear evolution problems. In particular homogenization procedures, correctors and a numerical algorithm for such problems are studied. The main results are the following: We prove a crucial compactness results of two-scale convergence type. LÄS MER

  4. 23. Partial differential equations and systems related to Morrey spaces

    Författare :Maria Alessandra Ragusa; Alexey Karapetyants; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : This PhD thesis deals with the study of well posedness, existence and regularity properties of solutions of partial differential equations and systems. Preparatory to the study of partial differential equations is the action of some integral operators, that are extensively used. LÄS MER

  5. 24. Localised Radial Basis Function Methods for Partial Differential Equations

    Författare :Victor Shcherbakov; Elisabeth Larsson; Grady B. Wright; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Radial basis function; Partition of unity; Computational finance; Option pricing; Credit default swap; Glaciology; Fluid dynamics; Non-Newtonian flow; Anisotropic RBF; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Radial basis function methods exhibit several very attractive properties such as a high order convergence of the approximated solution and flexibility to the domain geometry. However the method in its classical formulation becomes impractical for problems with relatively large numbers of degrees of freedom due to the ill-conditioning and dense structure of coefficient matrix. LÄS MER

  7. 25. On weak and strong convergence of numerical approximations of stochastic partial differential equations

    Författare :Fredrik Lindgren; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Additive noise; Cahn-Hilliard-Cook equation; Error estimate; Finite element; Hyperbolic equation; Parabolic equation; Rational approximation; Stochastic partial differential equation; Strong convergence; Truncation; Wiener process; Weak convergence; Weak convergence;

    Sammanfattning : This thesis is concerned with numerical approximation of linear stochastic partial differential equations driven by additive noise. In the first part, we develop a framework for the analysis of weak convergence and within this framework we analyze the stochastic heat equation, the stochastic wave equation, and the linearized stochastic Cahn-Hilliard, or the linearized Cahn-Hilliard-Cook equation. LÄS MER