Sökning: "a posteriori error"

Visar resultat 1 - 5 av 82 avhandlingar innehållade orden a posteriori error.

  1. 1. Time-domain Reconstruction Methods for Ultrasonic Array Imaging : A Statistical Approach

    Författare :Fredrik Lingvall; Tadeusz Stepinski; Karl-Jörg Langenberg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; Ultrasonic array imaging; synthetic aperture imaging; maximum a posteriori estimation; linear minimum mean squared error estimation; SAFT; Bayesian image reconstruction; Signalbehandling; Signal processing; Signalbehandling; Signal Processing; signalbehandling;

    Sammanfattning : This thesis is concerned with reconstruction techniques for ultrasonic array imaging based on a statistical approach. The reconstruction problem is posed as the estimation of an image consisting of scattering strengths. LÄS MER

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

    Författare :Mats Boman; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : 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. LÄS MER

  4. 3. On adaptive finite element methods based on a posteriori estimates

    Författare :Axel Målqvist; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite element method; Galerkin; duality; a posteriori error estimation; adaptivity; Poisson equation; boundary penalty method; Helmholtz equation; pollution; variational multiscale method; adaptivity;

    Sammanfattning : .... LÄS MER

  5. 4. Mathematical analysis and approximation of a multiscale elliptic-parabolic system

    Författare :Omar Richardson; Adrian Muntean; Alfred Schmidt; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Two-scale modelling; two-scale Galerkin approximation; inverse Robin estimates; elliptic-parabolic system; a priori analysis; a posteriori error estimators; Matematik; Mathematics;

    Sammanfattning : We study a two-scale coupled system consisting of a macroscopic elliptic equation and a microscopic parabolic equation. This system models the interplay between a gas and liquid close to equilibrium within a porous medium with distributed microstructures. We use formal homogenization arguments to derive the target system. LÄS MER

  7. 5. A moving boundary problem for capturing the penetration of diffusant concentration into rubbers : Modeling, simulation and analysis

    Författare :Surendra Nepal; Adrian Muntean; Yosief Wondmagegne; Magnus Ögren; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Moving boundary problem; finite element method; a priori error estimate; a posteriori error estimate; order of convergence; diffusion of chemicals into rubber; swelling; Matematik; Mathematics;

    Sammanfattning : We propose a moving-boundary scenario to model the penetration of diffusants into rubbers. Immobilizing the moving boundary by using the well-known Landau transformation transforms the original governing equations into new equations posed in a fixed domain. LÄS MER