Search for dissertations about: "Conjugate gradient"

Showing result 1 - 5 of 19 swedish dissertations containing the words Conjugate gradient.

  2. 1. Algorithms for a Partially Regularized Least Squares Problem

    Author : Ingegerd Skoglund; Tommy Elfving; Inge Söderkvist; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Least squares; Regularization; Block-matrices; Conjugate gradient; QR-factorization; Cross-validation; Numerical analysis; Numerisk analys;

    Abstract : Vid analys av vattenprover tagna från t.ex. ett vattendrag betäms halten av olika ämnen. Dessa halter är ofta beroende av vattenföringen. READ MORE

  4. 2. Utilizing Problem Structure in Optimization of Radiation Therapy

    Author : Fredrik Carlsson; Anders Forsgren; Edwin Romeijn; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Optimization; intensity-modulated radiation therapy; conjugate-gradient method; step-and-shoot delivery; column generation; quasi-Newton method; regularization; sequential quadratic programming; Optimization; systems theory; Optimeringslära; systemteori;

    Abstract : In this thesis, optimization approaches for intensity-modulated radiation therapy are developed and evaluated with focus on numerical efficiency and treatment delivery aspects. The first two papers deal with strategies for solving fluence map optimization problems efficiently while avoiding solutions with jagged fluence profiles. READ MORE

  5. 3. Experimental and analytical study of thermal mixing at reactor conditions

    Author : Mattia Bergagio; Henryk Anglart; Horst-Michael Prasser; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-cycle thermal fatigue; Hilbert-Huang transform; large eddy; WALE; rainflow; inverse heat conduction; adjoint conjugate gradient; Energy Technology; Energiteknik; Fysik; Physics;

    Abstract : High-cycle thermal fatigue due to turbulent mixing of streams at distinct temperatures is an interdisciplinary issue affecting safety and life extension of existing reactors together with the design of new reactors. It is challenging to model damage and thermal loads arising from the above mixing. READ MORE

  6. 4. On Methods for Solving Symmetric Systems of Linear Equations Arising in Optimization

    Author : Tove Odland; Anders Forsgren; William W. Hager; KTH; []
    Keywords : 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;

    Abstract : 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. READ MORE

  7. 5. High Performance Computing for the Optimization of Radiation Therapy Treatment Plans

    Author : Felix Liu; Stefano Markidis; Artur Podobas; Albin Fredriksson; David Keyes; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; HPC; Radiation Therapy; Optimization; Numerical Linear Algebra; Interior Point Methods; Datalogi; Computer Science;

    Abstract : Radiation therapy is a clinical field in which computer simulations play a crucial role. Before patients undergo radiation therapy, an individual treatment plan for each patient needs to be created based on the specifics of their case (a process often referred to as \emph{treatment planning}). READ MORE