Sökning: "covariance matrices"

Visar resultat 6 - 10 av 48 avhandlingar innehållade orden covariance matrices.

  1. 6. Estimation in Multivariate Linear Models with Linearly Structured Covariance Matrices

    Författare :Joseph Nzabanita; Dietrich von Rosen; Martin Singull; Daniel Klein; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis focuses on the problem of estimating parameters in multivariate linear models where particularly the mean has a bilinear structure and the covariance matrix has a linear structure. Most of techniques in statistical modeling rely on the assumption that data were generated from the normal distribution. LÄS MER

  3. 7. A study of multilevel models with block circular  symmetric covariance structures

    Författare :Yuli Liang; Tatjana von Rosen; Dietrich von Rosen; Abdullah Almasri; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Block circular symmetry; Covariance matrix; Explicit solution; Maximum likelihood estimator; Multilevel model; Spectrum; statistik; Statistics; Matematik;

    Sammanfattning : This thesis concerns the study of multilevel models with specific patterned covariance structures and addresses the issues of maximum likelihoodestimation. In particular, circular symmetric hierarchical datastructures are considered. LÄS MER

  4. 8. Contributions to Estimation and Testing Block Covariance Structures in Multivariate Normal Models

    Författare :Yuli Liang; Tatjana von Rosen; Dietrich von Rosen; Ivan Žežula; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Block circular symmetry; covariance parameters; explicit maximum likelihood estimator; likelihood ratio test; restricted model; Toeplitz matrix; Statistics; statistik;

    Sammanfattning : This thesis concerns inference problems in balanced random effects models with a so-called block circular Toeplitz covariance structure. This class of covariance structures describes the dependency of some specific multivariate two-level data when both compound symmetry and circular symmetry appear simultaneously. LÄS MER

  5. 9. Modeling Realized Covariance of Asset Returns

    Författare :Gustav Alfelt; Joanna Tyrcha; Taras Bodnar; Tatjana von Rosen; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematical Statistics; matematisk statistik;

    Sammanfattning : In this thesis, which consists of two papers, we consider the modeling of positive definitive symmetric matrices, in particular covariance matrices of financial asset returns. The return covariance matrix describes the magnitude in which prices of financial assets tend to change over time, and how price changes between different assets are related. LÄS MER

  7. 10. Bayesian Inference with Unknown Noise Covariance

    Författare :Lennart Svensson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : This thesis studies Bayesian methods in statistical signal processing. A central theme is that the treatment of the unknown noise covariance matrix is of chief concern for all scenarios. As a first application, the detection of land mines using infrared techniques is investigated. LÄS MER