Sökning: "Approximation Model"

Visar resultat 1 - 5 av 364 uppsatser innehållade orden Approximation Model.

  1. 1. Feature Selection for Microarray Data via Stochastic Approximation

    Master-uppsats, Göteborgs universitet/Institutionen för data- och informationsteknik

    Författare :Erik Rosvall; [2024-03-18]
    Nyckelord :feature selection; feature ranking; microarray data; stochastic approximation; Barzilai and Borwein method; Machine Learning; AI;

    Sammanfattning : This thesis explores the challenge of feature selection (FS) in machine learning, which involves reducing the dimensionality of data. The selection of a relevant subset of features from a larger pool has demonstrated its effectiveness in enhancing the performance of various machine learning algorithms. LÄS MER

  3. 2. Solving the incompressible Navier-Stokes equations in 3-D to model gas flow in a room

    Uppsats för yrkesexamina på avancerad nivå, Uppsala universitet/Avdelningen för beräkningsvetenskap

    Författare :Fredrik Malmström; [2024]
    Nyckelord :;

    Sammanfattning : The thesis proposes to model the flow of gases in a room by solving the incompressible Navier-Stokes equations in three dimensions. The transportationof scalars such as temperature and concentration of CO2 is modeled by solving the advection-diffusion equation, and the effects of temperature on thevelocity is accounted for by employing the Boussinesq approximation. LÄS MER

  4. 3. Spatio-temporal analysis of COVID-19 in Västra Götaland, Sweden

    Master-uppsats, Göteborgs universitet/Institutionen för matematiska vetenskaper

    Författare :Natalia Andreeva; [2023-08-23]
    Nyckelord :;

    Sammanfattning : Spatio-temporal analysis of COVID-19 data with the two different statistical approaches is the main objective of this thesis. The first classical approach, the Endemic-Epidemic framework (Held et al., 2005) is a class of multivariate time-series models for the incidence counts, obtained from the surveillance systems. LÄS MER

  5. 4. Fitting a photospheric prompt emission model to GRB data: The Kompaneets RMS approximation (KRA)

    Master-uppsats, KTH/Fysik

    Författare :Oscar Wistemar; [2023]
    Nyckelord :Gamma-Ray Bursts; Astrophysics; Engineering Physics; Gamma-Blixtar; Astrofysik; Teknisk Fysik;

    Sammanfattning : Gamma-ray bursts (GRBs) are some of the most energetic events in the universe. Shocks occurring below the photosphere are likely radiation mediated shocks (RMSs) and are suspected to shape the spectra. Due to computational costs of simulating RMSs, models had not been fitted to data and a faster model was needed. LÄS MER

  7. 5. 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