Sökning: "Helmholtz operator"
Visar resultat 1 - 5 av 10 avhandlingar innehållade orden Helmholtz operator.
1. Semi-classical approximations of Quantum Mechanical problems
Sammanfattning : .... LÄS MER
2. Numerical methods for waveguide modelling
Sammanfattning : 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. LÄS MER
3. Spectra of elliptic operators and applications
Sammanfattning : 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. LÄS MER
4. Accelerated Dirichlet-Robin Alternating Algorithm for Solving the Cauchy Problem for an Elliptic Equation using Krylov Subspaces
Sammanfattning : 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. LÄS MER
5. Regularization methods for solving Cauchy problems for elliptic and degenerate elliptic equations
Sammanfattning : 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. LÄS MER