Sökning: "differential equations"

Visar resultat 6 - 10 av 477 avhandlingar innehållade orden differential equations.

  1. 6. Topics in analytic theory of partial differential equations

    Författare :Sergei Chulkov; Jan-Erik Björk; Mattias Jonsson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; partial differential equations; Algebra; geometry and mathematical analysis; Algebra; geometri och analys;

    Sammanfattning : The thesis consists of three papers I, II III devoted to some topics in analytic theory of partial differential equations. The main paper is II. In this paper we study a version of the classical problem on the convergence of formal solutions of systems of partial differential equations. LÄS MER

  3. 7. Differential-algebraic equations and matrix-valued singular perturbation

    Författare :Henrik Tidefelt; Torkel Glad; Ulf Jönsson; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Differential-algebraic equations; uncertainty; singular perturbation; state estimation; Automatic control; Reglerteknik;

    Sammanfattning : With the arrival of modern component-based modeling tools for dynamic systems, the differential-algebraic equation form is increasing in popularity as it is general enough to handle the resulting models. However, if uncertainty is allowed in the equations — no matter how small — this thesis stresses that such equations generally become ill-posed. LÄS MER

  4. 8. Exponential integrators for stochastic partial differential equations

    Författare :Rikard Anton; David Cohen; Christian Engström; Stig Larsson; Annika Lang; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Stochastic partial differential equations; numerical methods; stochastic exponential integrator; strong convergence; trace formulas;

    Sammanfattning : Stochastic partial differential equations (SPDEs) have during the past decades become an important tool for modeling systems which are influenced by randomness. Because of the complex nature of SPDEs, knowledge of efficient numerical methods with good convergence and geometric properties is of considerable importance. LÄS MER

  5. 9. The Skorohod problem and weak approximation of stochastic differential equations in time-dependent domains

    Författare :Thomas Önskog; Kaj Nyström; Leif Persson; Johan Tysk; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Skorohod problem; weak approximation; time-dependent domain; stochastic differential equations; parabolic partial differential equations; oblique reflection; stopped diffusions; Euler scheme; adaptive methods; sensitivity analysis; financial derivatives; Greeks ; MATHEMATICS; MATEMATIK; Mathematics; matematik;

    Sammanfattning : This thesis consists of a summary and four scientific articles. All four articles consider various aspects of stochastic differential equations and the purpose of the summary is to provide an introduction to this subject and to supply the notions required in order to fully understand the articles. LÄS MER

  7. 10. Topics in Nonlinear Elliptic Differential Equations

    Författare :Shoyeb Waliullah; Andrzej Szulkin; Thomas Bartsch; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Concentration-compactness principle; critical Sobolev exponent; symmetric solutions of elliptic equations; degenerate elliptic equation; Nehari manifold; Caffarelli-Kohn-Nirenberg inequality; infinitely many solutions; MATHEMATICS; MATEMATIK; Mathematics; matematik;

    Sammanfattning : In this thesis we examine the existence of solutions to nonlinear elliptic partial differential equations via variational methods.In Paper I we consider the existence of constrained minimizers which correspond to solutions of equations involving the iterated Laplacian, the iterated p-Laplacian and the critical Sobolev exponent. LÄS MER