Search for dissertations about: "Spectral splitting"

Showing result 1 - 5 of 29 swedish dissertations containing the words Spectral splitting.

2. 1. Novel Algorithms for Optimal Transport via Splitting Methods

   Author : Jacob Lindbäck; Mikael Johansson; Jérôme Malick; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; optimal transport; splitting methods; Optimeringslära och systemteori; Optimization and Systems Theory;

   Abstract : This thesis studies how the Douglas–Rachford splitting technique can be leveraged for scalable computational optimal transport (OT). By carefully splitting the problem, we derive an algorithm with several advantages. READ MORE

4. 2. Numerical Methods for Wave Propagation : Analysis and Applications in Quantum Dynamics

   Author : Emil Kieri; Sverker Holmgren; Vasile Gradinaru; Hans O. Karlsson; Tobias Jahnke; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

   Abstract : We study numerical methods for time-dependent partial differential equations describing wave propagation, primarily applied to problems in quantum dynamics governed by the time-dependent Schrödinger equation (TDSE). We consider both methods for spatial approximation and for time stepping. READ MORE

5. 3. Directional Decomposition in Anisotropic Heterogeneous Media for Acoustic and Electromagnetic Fields

   Author : B. Lars G. Jonsson; KTH; []
   Keywords : directional wave-field decomposition; wave splitting; spectral reduction; aourstic anisotropy; electromagnetic anisotropy; generalized eigenvalue problem;

   Abstract : Directional wave-field decomposition for heterogeneousanisotropic media with in-stantaneous response is establishedfor both the acoustic and the electromagnetic equations.We derive a sufficient condition for ellipticity of thesystem's matrix in the Laplace domain and show that theconstruction of the splitting matrix via a Dunford-Taylorintegral over the resolvent of the non-compact, non-normalsystem's matrix is well de ned. READ MORE

6. 4. Asymptotic analysis of solutions to elliptic and parabolic problems

   Author : Peter Rand; Vladimir Kozlov; Mikael Langer; Vitali Liskevich; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Asymptotic behaviour; The Emden-Fowler equation; Parabolic system; Spectral splitting; Cylinder; Perturbation; MATHEMATICS; MATEMATIK;

   Abstract : In the thesis we consider two types of problems. In Paper 1, we studysmall solutions to a time-independent nonlinear elliptic partial differential equation of Emden-Fowler type in a semi-infnite cylinder. The asymptotic behaviour of these solutions at infnity is determined. First, the equation under the Neumann boundary condition is studied. READ MORE

7. 5. Structure and Dynamics of Core-Excited Species

   Author : Oksana Travnikova; Maria Novella Piancastelli; Svante Svensson; Denis Ceolin; Pascal Lablanqui; Uppsala universitet; []
   Keywords : Physics; Synchrotron radiation; X-ray Photoelectron Spectroscopy XPS ; X-ray Absorption Spectroscopy XAS ; Resonant Auger Spectroscopy RAS ; Auger Electron Spectroscopy AES ; Energy-Selected Auger Electron PhotoIon COincidence ES-AEPICO ; core excitation; core ionization; linear free energy relationships LFER ; molecular-field splitting; substituent effects; nuclear dynamics; isomerization; Cl2; N2O; methane derivatives; allene; acetylacetone; Fysik;

   Abstract : In this thesis we have performed core-electron spectroscopy studies of gas phase molecular systems starting with smaller diatomic, continuing with triatomic and extending our research to more complex polyatomic ones. We can subdivide the results presented here into two categories: the first one focusing on electronic fine structure and effect of the chemical bonds on molecular core-levels and the other one dealing with nuclear dynamics induced by creation of a core hole. READ MORE