Sökning: "eigenvalues"

Visar resultat 1 - 5 av 110 avhandlingar innehållade ordet eigenvalues.

  1. 1. Matrix-Less Methods for Computing Eigenvalues of Large Structured Matrices

    Författare :Sven-Erik Ekström; Maya Neytcheva; Stefano Serra-Capizzano; Carlo Garoni; Lothar Reichel; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Toeplitz matrices; eigenvalues; eigenvalue asymptotics; polynomial interpolation; extrapolation; generating function and spectral symbol; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : When modeling natural phenomena with linear partial differential equations, the discretized system of equations is in general represented by a matrix. To solve or analyze these systems, we are often interested in the spectral behavior of these matrices. LÄS MER

  3. 2. Krylov Subspace Methods for Linear Systems, Eigenvalues and Model Order Reduction

    Författare :Daniel Skoogh; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; eigenvalues; eigenvectors; sparse; parallel; rational; Krylov; shift; invert; Arnoldi; linear systems; iterative; model; reduction; passive; 65F15; 65F50; 65Y05; 65F10; 93A30; 93B40; rational;

    Sammanfattning : New variants of Krylov subspace methods for numerical solution of linear systems, eigenvalue, and model order reduction problems are described. A new method to solve linear systems of equations with several right-hand sides is described. LÄS MER

  4. 3. Some new results concerning general weighted regular Sturm-Liouville problems

    Författare :Mervis Kikonko; Lars-Erik Persson; Peter Wall; Angelo B. Mingarelli; Alexey Karapetyants; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Partial differential equations; Sturm-Liouville problem; Right-definite; left-definite; non-definite; indefinite; Dirichlet problem; spectrum; eigenvalues; non-real eigenvalues; Richardson number; Richardson index; turning point; Mathematics; Matematik;

    Sammanfattning : In this PhD thesis we study some weighted regular Sturm-Liouville problems in which the weight function takes on both positive and negative signs in an appropriate interval [a,b]. With such  problems there is the possible existence of non-real eigenvalues, unlike in the definite case (i.e. LÄS MER

  5. 4. Heterogeneous Materials - Diffusion, Laplace Spectrum, and Nuclear Magnetic Resonance

    Författare :Matias Nordin; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; eigenfunctions; eigenvalues; propagator; diffusion; Laplace operator; Nuclear Magnetic Resonance;

    Sammanfattning : In this thesis diffusion in heterogeneous materials is studied using spectral analysisof the Laplace operator. Relations to the effective diffusion constant and therelaxation rate of the time-dependent diffusion coefficient for porous systems arederived from the Laplace operator’s spectrum. LÄS MER

  7. 5. Bandwidth-reduced Linear Models of Non-continuous Power System Components

    Författare :Jonas Persson; Lennart Söder; Liisa Haarla; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Linearization methods; frequency analysis; transient analysis; time-domain simulations; eigenvalues; linear analysis; TCSC; Electric power engineering; Elkraftteknik;

    Sammanfattning : Denna avhandling är fokuserad på modellering av elkraftsystemkomponenter och deras representation vid simuleringar av elkraftsystem. Avhandlingen jämför olika linjäriseringstekniker. Dessa tekniker är såväl numeriska som analytiska och används vid linjärisering av ett dynamiskt system. LÄS MER