Search for dissertations about: "variable splitting"
Showing result 6 - 10 of 22 swedish dissertations containing the words variable splitting.
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6. A Fast Method for Solving the Helmholtz Equation Based on Wave Splitting
Abstract : In this thesis, we propose and analyze a fast method for computing the solution of the Helmholtz equation in a bounded domain with a variable wave speed function. The method is based on wave splitting. The Helmholtz equation is first split into one--way wave equations which are then solved iteratively for a given tolerance. READ MORE
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7. Nuclear spin relaxation in paramagnetic metal complexes and the slow motion problem for the electron spin
Abstract : A general theory is derived for the relaxation of ligand nuclei in a solution of slowly tumbling paramagnetic complexes with a static zero-field splitting interaction. The Solomon-Bloembergen-Morgan theory, which is the approach traditionally taken in studies of this kind, is shown to be the limit of the new theory when the electron Zeeman interaction dominates over the zerofield splitting interaction and when the exchange rate is significant. READ MORE
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8. Robust preconditioning methods for algebraic problems, arising in multi-phase flow models
Abstract : The aim of the project is to construct, analyse and implement fast and reliable numerical solution methods to simulate multi-phase flow, modeled by a coupled system consisting of the time-dependent Cahn-Hilliard and incompressible Navier-Stokes equations with variable viscosity and variable density. This thesis mainly discusses the efficient solution methods for the latter equations aiming at constructing preconditioners, which are numerically and computationally efficient, and robust with respect to various problem, discretization and method parameters. READ MORE
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9. On some Numerical Methods and Solution Techniques for Incompressible Flow Problems
Abstract : The focus of this work is on numerical solution methods for solving the incompressible Navier-Stokes equations, which consist of a set of coupled nonlinear partial differential equations.In general, after linearization and finite element discretization in space, the original nonlinear problem is converted into finding the solutions of a sequence of linear systems of equations. READ MORE
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10. Adaptive image compression with wavelet packets and empirical mode decomposition
Abstract : This thesis addresses the problem of using wavelet packets and empirical mode decomposition (EMD) for image compression. The wavelet packet basis selection algorithm is studied through an extensive experimental survey of the generated decomposition trees. READ MORE