Search for dissertations about: "stochastic wave equation"

Showing result 6 - 10 of 11 swedish dissertations containing the words stochastic wave equation.

  2. 6. On flexible random field models for spatial statistics: Spatial mixture models and deformed SPDE models

    Author : Anders Hildeman; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Spatial statistics; Significant wave height; Spatial mixture model; Stochastic partial differential equation; Log-Gaussian Cox process; Point process; Gaussian random field; Substitute-CT;

    Abstract : Spatial random fields are one of the key concepts in statistical analysis of spatial data. The random field explains the spatial dependency and serves the purpose of regularizing interpolation of measured values or to act as an explanatory model. READ MORE

  4. 7. Multiscale methods for evolution problems

    Author : Per Ljung; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; localized orthogonal decomposition; multiscale; stochastic partial differential equations; Strongly damped wave equation; finite element method; spatial network models; parabolic equations;

    Abstract : In this thesis we develop and analyze generalized finite element methods for time-dependent partial differential equations (PDEs). The focus lies on equations with rapidly varying coefficients, for which the classical finite element method is insufficient, as it requires a mesh fine enough to resolve the data. READ MORE

  5. 8. On Monte Carlo Operators for Studying Collisional Relaxation in Toroidal Plasmas

    Author : Qaisar Mukhtar; Torbjörn Hellsten; Tainia Kurki-Suonio; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Fusion plasma; thermonuclear fusion; tokamak; Coulomb collisions; stochastic differential equations with singular diffusion coefficients; Monte Carlo schemes; spatial diffusion; modelling; Fokker-Planck equation; RF-heating.;

    Abstract : This thesis concerns modelling of Coulomb collisions in toroidal plasma with Monte Carlo operators, which is important for many applications such as heating, current drive and collisional transport in fusion plasmas. Collisions relax the distribution functions towards local isotropic ones and transfer power to the background species when they are perturbed e. READ MORE

  6. 9. Uncertainty quantification for wave propagation and flow problems with random data

    Author : Markus Wahlsten; Jan Nordström; Per Pettersson; Rémi Abgrall; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis we study partial differential equations with random inputs. The effects that different boundary conditions with random data and uncertain geometries have on the solution are analyzed. Further, comparisons and couplings between different uncertainty quantification methods are performed. READ MORE

  7. 10. Uncertainty quantification for high frequency waves

    Author : Gabriela Malenova; Olof Runborg; Fabio Nobile; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Abstract : We consider high frequency waves satisfying the scalar wave equation with highly oscillatory initial data represented by a short wavelength ε. The speed of propagation of the medium as well as the phase and amplitude of the initial data is assumed to be uncertain, described by a finite number of independent random variables with known probability distributions. READ MORE