Sökning: "scaling method"

Visar resultat 1 - 5 av 267 avhandlingar innehållade orden scaling method.

  1. 1. Accurate techniques for 2D electromagnetic scattering

    Författare :Imad Akeab; Sven-Erik Sandström; Alexander Nosich; Linnéuniversitetet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Integral equations; method of moments; sparsity; scaling; shadow boundary; B-S;

    Sammanfattning : This thesis consists of three parts. The first part is an introduction and referencessome recent work on 2D electromagnetic scattering problems at high frequencies. It alsopresents the basic integral equation types for impenetrable objects. A brief discussionof the standard elements of the method of moments is followed by summaries of thepapers. LÄS MER

  3. 2. On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

    Författare :Tove Odland; Anders Forsgren; William W. Hager; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; symmetric system of linear equations; method of conjugate gradients; quasi-Newton method; unconstrained optimization; unconstrained quadratic optimiza- tion; Krylov subspace method; unnormalized Lanczos vectors; minimum-residual method; symmetriska linjära ekvationssystem; konjugerade gradientmetoden; kvasi- Newtonmetoder; optimering utan bivillkor; kvadratisk optimering utan bivillkor; Kry- lovunderrumsmetoder; icke-normaliserade Lanczosvektorer; minimum-residualmetoden; Mathematics; Matematik;

    Sammanfattning : In this thesis we present research on mathematical properties of methods for solv- ing symmetric systems of linear equations that arise in various optimization problem formulations and in methods for solving such problems.In the first and third paper (Paper A and Paper C), we consider the connection be- tween the method of conjugate gradients and quasi-Newton methods on strictly convex quadratic optimization problems or equivalently on a symmetric system of linear equa- tions with a positive definite matrix. LÄS MER

  4. 3. CFD Methods for Predicting Aircraft Scaling Effects

    Författare :Karl Pettersson; Arthur Rizzi; Bryan Richards; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; CFD; Scaling Effects; Boundary Layer Transition; Preconditioning; Vehicle engineering; Farkostteknik;

    Sammanfattning : This thesis deals with the problems of scaling aerodynamic data from wind tunnel to free flight  conditions. The main challenges when this scaling should be performed is how the model support, wall interference and the potentially lower Reynolds number in the windtunnel should be corrected. LÄS MER

  5. 4. Aspects of adaptive mesh refinement in the spectral element method

    Författare :Nicolas Offermans; Philipp Schlatter; Ananias Tomboulides; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Error estimators; mesh refinement; adaptivity; spectral element method; algebraic multigrid method; NACA4412; periodic hill case.; Engineering Mechanics; Teknisk mekanik;

    Sammanfattning : This thesis deals with the improvement of the efficiency of numerical simulations in computational fluid dynamics. Some of the limitations of current algorithms on future exascale supercomputers are addressed with the main goal of using adaptive mesh refinement for the simulation of turbulent and three-dimensional flows. LÄS MER

  7. 5. Bound states and resonances in three-body system

    Författare :Yarevsky Evgeny; Thomas N. Rescigno; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Three-body problem; Total angular momentum representation; Resonances; Complex Scaling Method; Finite Element Method; Eigenvalues problem.; Physics; fysik;

    Sammanfattning : The quantum three-body problem plays an important role in different branches of the modern physics. In the nuclear, atomic and molecular physics there exist a number of systems whose behaviour is naturally described in this framework. LÄS MER