Search for dissertations about: "higher order scattering"

Showing result 6 - 10 of 71 swedish dissertations containing the words higher order scattering.

  2. 6. Towards higher order immersed finite elements for the wave equation

    Author : Simon Sticko; Gunilla Kreiss; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Abstract : We consider solving the scalar wave equation using immersed finite elements. Such a method might be useful, for instance, in scattering problems when the geometry of the domain is not known a priori. For hyperbolic problems, the amount of computational work per dispersion error is generally lower when using higher order methods. READ MORE

  4. 7. Nonlinear Propagation of Optical Pulses and Beams

    Author : Magnus Karlsson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; self-phase modulation; optical wave breaking; paraxial-ray approximation; stimulated Raman scattering; nonlinear Schrödinger equation; optical collapse; modulational instability; higher-order dispersion; optical fibers; saturable nonlinearity; Kerr-nonlinearity; self-trapping; group-velocity dispersion; optical solitons; self-focusing;

    Abstract : The propagation of optical beams and pulses under the influence of nonlinear effects is characterized by a rich variety of phenomena and many potentially important applications. We analyse two main topics in this context: nonlinear beam propagation, and nonlinear pulse propagation in optical fibers. READ MORE

  5. 8. Antennas and Propagation from a Signal Processing Perspective

    Author : Thomas Svantesson; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diversity reception; parameter estimation; higher order modes; mutual coupling; sensor array processing; switched parasitic antennas; physical modeling; channel modeling; MIMO channels; channel capacity;

    Abstract : This thesis studies several topics within the area of antennas and propagation from a signal processing perspective. However, theory and methods from electromagnetics and communications have also been used, contributing to an interdisciplinary character of the thesis. READ MORE

  6. 9. Coupling mechanisms in scattering reactions involving small molecular systems

    Author : Patrik Hedvall; Åsa Larson; Magnus Gustafsson; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Theoretical Physics; teoretisk fysik;

    Abstract : In this thesis, theoretical ab initio treatments of two-body molecular collision reactions are studied, having in common that the interaction region including all coupling mechanisms driving the reaction amounts to a molecular description. The main goal is to gain an understanding in the underlying coupling mechanisms involved in these reactions. READ MORE

  7. 10. High Order Cut Finite Element Methods for Wave Equations

    Author : Simon Sticko; Gunilla Kreiss; Mats G. Larson; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Cut finite element; Wave equation; Immersed; Fictitious domain; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Abstract : This thesis considers wave propagation problems solved using finite element methods where a boundary or interface of the domain is not aligned with the computational mesh. Such methods are usually referred to as cut or immersed methods. READ MORE