Search for dissertations about: "discretisation"

Showing result 1 - 5 of 39 swedish dissertations containing the word discretisation.

2. 1. Methods for improving covariate balance in observational studies

   Author : Philip Fowler; Xavier de Luna; Ingeborg Waernbaum; Martin Huber; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; causal effect; coarsening; discretisation; proxy variables; register study; swedish social insurance agency; unobserved variables;

   Abstract : This thesis contributes to the field of causal inference, where the main interest is to estimate the effect of a treatment on some outcome. At its core, causal inference is an exercise in controlling for imbalance (differences) in covariate distributions between the treated and the controls, as such imbalances otherwise can bias estimates of causal effects. READ MORE

4. 2. On A Posteriori Error Estimation in the Maximum Norm

   Author : Mats Boman; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : In this thesis we consider residual-based a posteriori error estimates in the maximum norm for the finite element solution of some partial differential equations. The thesis consists of three papers. The first paper concerns a pointwise a posteriori error estimate for the time dependent obstacle problem. READ MORE

5. 3. Nucleon-Nucleon Scattering in a Wave-Packet Formalism

   Author : Sean Miller; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; nuclear physics; chiral potentials; two-nucleon scattering;

   Abstract : In this thesis I analyse the prospect of leveraging statistical analyses of the strong nuclear interaction by using the wave-packet continuum discretisation (WPCD) method to efficiently compute nucleon-nucleon (NN) scattering observables on a graphics processing unit (GPU). The WPCD method gives approximate solutions to the S-matrix at multiple scattering energies at the cost of a single eigendecomposition of the NN channel Hamiltonian. READ MORE

6. 4. Stable High-Order Finite Difference Methods for Aerodynamics

   Author : Magnus Svärd; Jan Nordström; Thomas Hagstrom; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; finite difference methods; high-order accuracy; summation-by-parts; stability; energy estimates; finite volume methods; Numerical analysis; Numerisk analys; Scientific Computing; Beräkningsvetenskap; Numerical Analysis;

   Abstract : In this thesis, the numerical solution of time-dependent partial differential equations (PDE) is studied. In particular high-order finite difference methods on Summation-by-parts (SBP) form are analysed and applied to model problems as well as the PDEs governing aerodynamics. READ MORE

7. 5. Eigenfrequency Analysis FE-Adaptivity and a Nonlinear Eigenproblem Algorithm

   Author : Patrik Hager; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear eigenvalue; finite element; adaptivity; superconvergent patch recovery; rational krylov;

   Abstract : Engineering often pose the problem of computing the frequencies with which a system oscillates and the corresponding displacement patterns the system forms, and in case damping is present then the rates of which the amplitudes of the displacement patterns decay are also required. It is necessary to compute these quantities within a prescribed accuracy and the effort required for the computations should be minimised. READ MORE