Sökning: "numerical approximation"

Visar resultat 16 - 20 av 284 avhandlingar innehållade orden numerical approximation.

  1. 16. Models for capturing the penetration of a diffusant concentration into rubber : Numerical analysis and simulation

    Författare :Surendra Nepal; Adrian Muntean; Nadja Ray; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; transport of diffusants; moving-boundary problem; finite element method; a priori and a posteriori error estimates; random walk method; two-scale coupled system; Matematik; Mathematics;

    Sammanfattning : Understanding the transport of diffusants into rubber plays an important role in forecasting the material's durability. In this regard, we study different models, conduct numerical analysis, and present simulation results that predict the evolution of the penetration front of diffusants. LÄS MER

  3. 17. Geometric Decompositions and Networks - Approximation Bounds and Algorithms

    Författare :Joachim Gudmundsson; Institutionen för datavetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computer technology; Systems engineering; kontroll; system; Delaunay triangulation; Computational geometry; TSP with neighborhoods; geometric spanners; covering polygons; Computer science; numerical analysis; systems; control; numerisk analys; Datalogi; algebraisk topologi; algebraic topology; Geometry; Data- och systemvetenskap; Geometri;

    Sammanfattning : In this thesis we focus on four problems in computational geometry: In the first four chapters we consider the problem of covering an arbitrary polygon with simpler polygons, i.e., rectangles. LÄS MER

  4. 18. Numerical Algorithms for Optimization Problems in Genetical Analysis

    Författare :Kateryna Mishchenko; Sverker Holmgren; Dmitrii Silvestrov; Lars Rönnegård; Ann-Charlotte Berglund Sonnhammer; Mälardalens högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantitative Trait Loci QTL ; restricted maximum likelihood REML ; variance components; average information AI matrix; Local optimization; Quasi-Newton method; Active Set method; Hessian approximation; BFGS update; Applied mathematics; Tillämpad matematik; Matematik tillämpad matematik;

    Sammanfattning : The focus of this thesis is on numerical algorithms for efficient solution of QTL analysis problem in genetics.Firstly, we consider QTL mapping problems where a standard least-squares model is used for computing the model fit. LÄS MER

  5. 19. Approximating Stochastic Partial Differential Equations with Finite Elements: Computation and Analysis

    Författare :Andreas Petersson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Lévy process; Lyapunov equation; white noise; finite element method; multilevel Monte Carlo; Monte Carlo; multiplicative noise; asymptotic mean square stability; stochastic heat equation; covariance operator; weak convergence; generalized Wiener process; numerical approximation; stochastic wave equation; Stochastic partial differential equations;

    Sammanfattning : Stochastic partial differential equations (SPDE) must be approximated in space and time to allow for the simulation of their solutions. In this thesis fully discrete approximations of such equations are considered, with an emphasis on finite element methods combined with rational semigroup approximations. LÄS MER

  7. 20. Stable High-Order Finite Difference Methods for Aerodynamics

    Författare :Magnus Svärd; Jan Nordström; Thomas Hagstrom; Uppsala universitet; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER