Search for dissertations about: "Matrix models"

Showing result 11 - 15 of 567 swedish dissertations containing the words Matrix models.

  2. 11. Statistical modeling and design in forestry : The case of single tree models

    Author : Leakemariam Berhe; Göran Arnoldsson; Göran Broström; Dieter Rasch; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Forest data; Covariance structures; Nonlinear mixed effects models; Tree taper models; Ds-optimal design; Replication-free design.; Statistics; Statistik;

    Abstract : Forest quantification methods have evolved from a simple graphical approach to complex regression models with stochastic structural components. Currently, mixed effects models methodology is receiving attention in the forestry literature. READ MORE

  4. 12. Modeling the covariance matrix of financial asset returns

    Author : Gustav Alfelt; Joanna Tyrcha; Taras Bodnar; Vasyl Golosnoy; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Realized covariance; Autoregressive time-series; Goodness-of-fit test; Matrix singularity; Portfolio theory; Wishart distribution; Matrix-variate gamma distribution; Parameter estimation; High-dimensional data; Moore-Penrose inverse; matematisk statistik; Mathematical Statistics;

    Abstract : The covariance matrix of asset returns, which describes the fluctuation of asset prices, plays a crucial role in understanding and predicting financial markets and economic systems. In recent years, the concept of realized covariance measures has become a popular way to accurately estimate return covariance matrices using high-frequency data. READ MORE

  5. 13. Strongly Correlated Models in One Dimension from a Density Matrix Renormalization Group Perspective

    Author : Stefan Rommer; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; matrix product states; impurities; density matrix renormalization group; Heisenberg model; spin chain; DMRG;

    Abstract : The density matrix renormalization group (DMRG) is a numerical method for studying low dimensional strongly correlated models. The study of these models is one of the most active areas of condensed matter physics today and has been spurred not only by the discovery of high temperature superconductivity but also by experiments on new compounds. READ MORE

  6. 14. Merging Parton Showers and Matrix Elements

    Author : Nils Lavesson; Teoretisk partikelfysik - Geonomgår omorganisation; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Parton Model; QCD Phenomenology; Phenomenological Models; QCD; Jets;

    Abstract : This thesis considers models for describing high energy particle collisions. Existing phenomonological models are modified and new implementations made in order to achive a better description of states with several hard jets. To predict final state hadrons, parton showers are used together with pheonomenological hadronization models. READ MORE

  7. 15. Rank Estimation in Elliptical Models : Estimation of Structured Rank Covariance Matrices and Asymptotics for Heteroscedastic Linear Regression

    Author : Kristi Kuljus; Silvelyn Zwanzig; Dietrich von Rosen; Jana Jureckova; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; elliptical distributions; multivariate ranks; rank covariance matrix; linear rank regression; heteroscedastic errors; linear rank statistics; Mathematical statistics; Matematisk statistik;

    Abstract : This thesis deals with univariate and multivariate rank methods in making statistical inference. It is assumed that the underlying distributions belong to the class of elliptical distributions. READ MORE