Sökning: "iterative solution methods"

Visar resultat 6 - 10 av 90 avhandlingar innehållade orden iterative solution methods.

  1. 6. Iterative Filtered Backprojection Methods for Helical Cone-Beam CT

    Författare :Johan Sunnegårdh; Michael Felsberg; Michel Defrise; Linköpings universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Iterative reconstruction; filtered backprojection; regularization; cone-beam CT; Medical engineering; Medicinsk teknik;

    Sammanfattning : State-of-the-art reconstruction algorithms for medical helical cone-beam Computed Tomography (CT) are of type non-exact Filtered Backprojection (FBP). They are attractive because of their simplicity and low computational cost, but they produce sub-optimal images with respect to artifacts, resolution, and noise. LÄS MER

  3. 7. Iterative and Adaptive PDE Solvers for Shared Memory Architectures

    Författare :Henrik Löf; Jarmo Rantakokko; Sverker Holmgren; Erik Hagersten; Mark Bull; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; partial differential equations; iterative methods; finite elements; conjugate gradients; adaptive mesh refinement; multigrid; cc-NUMA; distributed shared memory; OpenMP; page migration; TLB shoot-down; bandwidth minimization; reverse Cuthill-McKee; migrate-on-next-touch; affinity; temporal locality; chip multiprocessors; CMP; Beräkningsvetenskap; Scientific Computing;

    Sammanfattning : Scientific computing is used frequently in an increasing number of disciplines to accelerate scientific discovery. Many such computing problems involve the numerical solution of partial differential equations (PDE). LÄS MER

  4. 8. Robust preconditioned iterative solution methods for large-scale nonsymmetric problems

    Författare :Erik Bängtsson; Maya Neytcheva; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : We study robust, preconditioned, iterative solution methods for large-scale linear systems of equations, arising from different applications in geophysics and geotechnics.The first type of linear systems studied here, which are dense, arise from a boundary element type of discretization of crack propagation in brittle material. LÄS MER

  5. 9. The Use of Landweber Algorithm in Image Reconstruction

    Författare :Touraj Nikazad; Tommy Elfving; George Baravdish; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; convex feasibility; projection methods; simultaneous algorithms; iterative methods; stopping rules; semi-convergence; Numerical analysis; Numerisk analys;

    Sammanfattning : Ill-posed sets of linear equations typically arise when discretizing certain types of integral transforms. A well known example is image reconstruction, which can be modelled using the Radon transform. After expanding the solution into a finite series of basis functions a large, sparse and ill-conditioned linear system arises. LÄS MER

  7. 10. On Numerical Solution Methods for Block-Structured Discrete Systems

    Författare :Petia Boyanova; Maya Neytcheva; Oleg Iliev; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Preconditioning techniques; Finite element method; Two-by-two block matrices; Optimal order methods; AMLI method; Cahn-Hilliard equation; Multiphase flow; Inexact Newton method; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : The development, analysis, and implementation of efficient methods to solve algebraic systems of equations are main research directions in the field of numerical simulation and are the focus of this thesis. Due to their lesser demands for computer resources, iterative solution methods are the choice to make, when very large scale simulations have to be performed. LÄS MER