Sökning: "covariance matrices"

Visar resultat 16 - 20 av 48 avhandlingar innehållade orden covariance matrices.

1. 16. Comparative network analysis of human cancer: sparse graphical models with modular constraints and sample size correction

   Författare :José Sánchez; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Inverse covariance matrix; precision matrix; graphical models; high-dimension; low-sample; networks; sparsity; fused lasso; elastic net; cancer.; fused lasso;

   Sammanfattning : In the study of transcriptional data for different groups (e.g. cancer types) it's reasonable to assume that some dependencies between genes on a transcriptional or genetic variants level are common across groups. Also, that this property is preserved locally, thus defining a modular structure in the model networks. LÄS MER

3. 17. Network models with applications to genomic data: generalization, validation and uncertainty assessment

   Författare :José Sánchez; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Inverse covariance matrix; precision matrix; graphical models; high-dimension; low-sample; networks; sparsity; fused lasso; elastic net; cancer; TCGA pan cancer analysis; online resource; discriminant analysis; classification; networks;

   Sammanfattning : The aim of this thesis is to provide a framework for the estimation and analysis of transcription networks in human cancer. The methods we develop are applied to data collected by The Cancer Genome Atlas (TCGA) and supporting simulations are based on derived models in order to reflect real data structure. LÄS MER

4. 18. Data driven modeling in the presence of time series structure: : Improved bounds and effective algorithms

   Författare :Othmane Mazhar; Boualem Djehiche; Munther Dahleh; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Time series; Non-asymptotic estimation; Minimax; Change point detection; Hidden Markov model; State space model; Least square; Penalized Regression; Random covariance matrix; Concentration inequality; Chaining integral; Self-normalized martingale inequality; Cramér-Rao inequality; van Trees inequality; Matematisk statistik; Mathematical Statistics;

   Sammanfattning : This thesis consists of five appended papers devoted to modeling tasks where the desired models are learned from data sets with an underlying time series structure. We develop a statistical methodology for providing efficient estimators and analyzing their non-asymptotic behavior. LÄS MER

5. 19. On Estimation and Prediction in Linear Mixed Models : A new approach to studying equal BLUEs and BLUPs

   Författare :Azadeh Chizarifard; Tatjana von Rosen; Katarzyna Filipiak; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Best linear unbiased estimator; Best linear unbiased predictor; Linear zero function; Matrix equations; statistik; Statistics;

   Sammanfattning : Linear mixed models (LMMs) are widely used to analyze repeated, longitudinal, or clustered data in many disciplines, such as biology, medicine, psychology, sociology, economics, etc. One of the essential components of a linear mixed model is its covariance structure, i.e. LÄS MER

7. 20. Orthonormal Motion-Adaptive Transforms for Image Sequences

   Författare :Du Liu; Markus Flierl; Peter Schelkens; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : In this thesis, we propose and discuss a class of motion-adaptive transforms (MAT) to describe the temporal correlation in image sequences for compression. The temporal correlation is based on motion models, and undirected graphs are used to represent this correlation in image sequences. The transforms are adaptive to general motion fields. LÄS MER