Sökning: "Numerisk analys"

Visar resultat 1 - 5 av 430 avhandlingar innehållade orden Numerisk analys.

  1. 1. Adaptive time-integration for goal-oriented and coupled problems

    Författare :Peter Meisrimel; Numerisk analys; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; time-adaptivity; goal-oriented problems; error estimation; coupled problems; waveform relaxation; asynchronous methods; conjugate heat transfer;

    Sammanfattning : We consider efficient methods for the partitioned time-integration of multiphysics problems, which commonly exhibit a multiscale behavior, requiring independent time-grids. Examples are fluid structure interaction in e.g., the simulation of blood-flow or cooling of rocket engines, or ocean-atmosphere-vegetation interaction. LÄS MER

  2. 2. Numerical Approximation of Reaction and Diffusion Systems in Complex Cell Geometry

    Författare :Qasim Ali Chaudhry; Michael Hanke; Maya Gueorguieva Neytcheva; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Complex Cell Geometry; Reaction and Diffusion System; Metabolism in Biological Cells; Homogenization; Compartment Modelling; Numerical analysis; Numerisk analys;

    Sammanfattning : The mathematical modelling of the reaction and diffusion mechanism of lipophilic toxic compounds in the mammalian cell is a challenging task because of its considerable complexity and variation in the architecture of the cell. The heterogeneity of the cell regarding the enzyme distribution participating in the bio-transformation, makes the modelling even more difficult. LÄS MER

  3. 3. Coarse Graining Monte Carlo Methods for Wireless Channels and Stochastic Differential Equations

    Författare :Håkon Hoel; Anders Szepessy; Ola Hössjer; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Coarse graining; Monte Carlo Methods; Stochastic processes; Numerical analysis; Numerisk analys;

    Sammanfattning : This thesis consists of two papers considering different aspects of stochastic process modelling and the minimisation of computational cost. In the first paper, we analyse statistical signal properties and develop a Gaussian pro- cess model for scenarios with a moving receiver in a scattering environment, as in Clarke’s model, with the generalisation that noise is introduced through scatterers randomly flip- ping on and off as a function of time. LÄS MER

  4. 4. Multi-scale methods for wave propagation in heterogeneous media

    Författare :Henrik Holst; Bjorn Engquist; Nils Svanstedt; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; Numerisk analys;

    Sammanfattning : Multi-scale wave propagation problems are computationally costly to    solve by traditional techniques because the smallest scales must be    represented over a domain determined by the largest scales of the    problem.  We have developed new numerical methods for multi-scale wave    propagation in the framework of heterogeneous multi-scale methods. LÄS MER

  5. 5. High performance adaptive finite element methods for turbulent fluid flow

    Författare :Niclas Jansson; Johan Hoffman; Sverker Holmgren; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Numerical analysis; Numerisk analys;

    Sammanfattning : Understanding the mechanics of turbulent fluid flow is of key importance for industry and society as for example in aerodynamics and aero-acoustics. The massive computational cost for resolving all turbulent scales in a realistic problem makes direct numerical simulation of the underlying Navier-Stokes equations impossible. LÄS MER