Search for dissertations about: "Helmholtz operator"

Showing result 1 - 5 of 10 swedish dissertations containing the words Helmholtz operator.

  2. 1. Semi-classical approximations of Quantum Mechanical problems

    Author : Ulf Karlsson; KTH; []
    Keywords : Schrödinger equation; semiclassical analysis; multi-well potential; potential wells; scale functions; spectral interval; Agmon metric; interaction matrix; hierarchical potential; Helmholtz operator; Fourier integral operator; global phase; hyperbolic;

    Abstract : .... READ MORE

  4. 2. Numerical methods for waveguide modelling

    Author : Christer Johansson; Björn Engquist; Per Lötstedt; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Waveguide; finite element; hp-adaptivity; helmholtz; maxwell; Numerical analysis; Numerisk analys;

    Abstract : Waveguides are used to transmit electromagnetic signals. Their geometry is typically long and slender. This particular shape can be used in the design of efficient computational methods. Only special modes are transmitted and eigenvalue and eigenvector analysis becomes important. READ MORE

  5. 3. Spectra of elliptic operators and applications

    Author : Medet Nursultanov; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Helmholtz and Maxwell s equations; functional calculus; electromagnetic waveguide; acoustic waveguide; Sturm-Liouville operator; singular potential; asymptotics of eigenvalues; point interactions.;

    Abstract : In this thesis we consider several problems related to elliptic equations. Namely, we investigate Helmholtz and Maxwell's equations in Paper I and Sturm-Liouville spectral problem in Papers II,III. In Paper I we study time-harmonic electromagnetic and acoustic waveguide, modeled by an in�nite cylinder with a non-smooth cross section. READ MORE

  6. 4. Accelerated Dirichlet-Robin Alternating Algorithm for Solving the Cauchy Problem for an Elliptic Equation using Krylov Subspaces

    Author : Jennifer Chepkorir; Vladimir Kozlov; Fredrik Berntsson; Linus Carlsson; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis, we study the Cauchy problem for an elliptic equation. We use Dirichlet-Robin iterations for solving the Cauchy problem. This allows us to include in our consideration elliptic equations with variable coefficient as well as Helmholtz type equations. READ MORE

  7. 5. Regularization methods for solving Cauchy problems for elliptic and degenerate elliptic equations

    Author : Jennifer Chepkorir; Vladimir Kozlov; Fredrik Berntsson; Alexei Iantchenko; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis, we study Cauchy problems for the elliptic and degenerate elliptic equations. These problems are ill-posed. We split the boundary of the domain into two parts. On one of them, say Γ0, we have available Cauchy data and on remaining part Γ1 we introduce unknown Robin data. READ MORE