Sökning: "Function Approximation"

Visar resultat 1 - 5 av 163 uppsatser innehållade orden Function Approximation.

  1. 1. Estimating Diffusion Tensor Distributions With Neural Networks

    Master-uppsats, Linköpings universitet/Algebra, geometri och diskret matematik; Linköpings universitet/Tekniska fakulteten

    Författare :Rimaz Nismi; [2024]
    Nyckelord :Diffusion; Magnetic Resonance Imaging; MRI; Neural Networks; Optimal transport; Earth mover s distance; Sinkhorn distance;

    Sammanfattning : Magnetic Resonance Imaging (MRI) is an essential healthcare technology, with diffusion MRI being a specialized technique. Diffusion MRI exploits the inherent diffusion of water molecules within the human body to produce a high-resolution tissue image. An MRI image contains information about a 3D volume in space, composed of 3D units called voxels. LÄS MER

  3. 2. Effects of Ultrafast Ionization in X-ray Coherent Diffraction Imaging

    Master-uppsats, KTH/Kemi

    Författare :Arezu Sehati; [2023]
    Nyckelord :Coherent Diffraction Imaging; X-ray Free Electron Lasers; Refractive index; Core-shell nanoclusters; Rare-gas ionization; Koherent Diffraktionsavbildning; Röntgenfrielektronlaser; Brytningsindex; Core-shell-nanokluster; Ädelgasjonisering;

    Sammanfattning : Koherent Diffraktionsavbildning med en intensiv röntgenpuls från en Frielektronlaser har möjliggjort strukturbestämning av isolerade nanopartiklar som inte går att studera med hjälp av konventionella metoder, så som elektronmikroskopi. En mycket kort pulslängd tillsammans med spridningssignalens beroende av objektets elektroniska struktur medför också möjligheten att studera inducerad ultrasnabb dynamik med denna teknik. LÄS MER

  4. 3. Numerical Simulations of Resonant Tunnelling Diodes

    Kandidat-uppsats, KTH/Skolan för teknikvetenskap (SCI)

    Författare :Love Sundström; Alexander Holmström Janeld; [2023]
    Nyckelord :Quantum mechanics; numerical methods; resonant tunnelling diode;

    Sammanfattning : In this thesis, four different numerical techniques are implemented for the purpose of simulating resonant tunnelling diodes (RTDs). The chosen methods were: piecewise constant transfer matrix (TMM-C), piecewise linear transfer matrix (TMM-L), quantum transmitting boundary method (QTBM), and the Crank-Nicolson method (CN). LÄS MER

  5. 4. Discussion of Python Implementation Techniques for Discontinuous Galerkin Methods

    Kandidat-uppsats, Lunds universitet/Matematik (naturvetenskapliga fakulteten); Lunds universitet/Matematikcentrum

    Författare :Ulf Vestberg; [2023]
    Nyckelord :Best approximation; Orthogonal polynomials; Legendre polynomials; Integration; Full tensor product; Sum-factorization; Dune; Mathematics and Statistics;

    Sammanfattning : This paper discusses implementation techniques for integration methods within the Discontinuous Galerkin Methods. These methods are used to approximate solutions for differential equations. To do so, one must compute a polynomial, which is an approximation of the used function. LÄS MER

  7. 5. Electron-skyrmion systems, in and out of equilibrium, and isolated or contacted to reservoirs

    Magister-uppsats, Lunds universitet/Matematisk fysik; Lunds universitet/Fysiska institutionen

    Författare :Emil Adam Jonatan Östberg; [2023]
    Nyckelord :skyrmion; skyrmions; NEGF; freen s function; quantum transport; non-equlibrium; topology; topological charge; skyrmionics; current induced; open system; Physics and Astronomy;

    Sammanfattning : A Kondo lattice skyrmion model in contact with a macroscopic environment is simulated to explore skyrmion dynamics, which is an extension of previous work. The system is simulated using non-equilibrium Green's functions within the generalized Kadanoff-Baym ansatz and the wide band limit. LÄS MER