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Visar resultat 1 - 5 av 46 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Some Markov Processes in Finance and Kinetics : Markov Processes

   Författare :Mattias Sunden; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; CGMY process; Collision kernel; Direct simulation Monte Carlo; Diffusion approximation; Extreme value theory; Feller process; Generalized hyperbolic process; Generalized $z$-process; Infinitesimal generator; Laplace-Beltrami operator; L evy Processes; Long-tailed distribution; Kac equation; Kac model; Markov process; Semigroup; Semi-heavy tailed distirbution; Spectral gap; Subexponential distibrution; Superexponential distribution; Tauberian theorem; Thermostat.; Diffusion approximation;

   Sammanfattning : This thesis consists of four papers. The first two papers treat extremes for L\'evy processes, while papers three and four treat the Kac model with unbounded collision kernel. LÄS MER

3. 2. Scalable Bayesian spatial analysis with Gaussian Markov random fields

   Författare :Per Sidén; Mattias Villani; Anders Eklund; Håvard Rue; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spatial statistics; Bayesian statistics; Gaussian Markov random fields; fMRI; Machine learning; Spatial statistik; Bayesiansk statistik; Gaussiska Markov-fält; fMRI; Maskininlärning;

   Sammanfattning : Accurate statistical analysis of spatial data is important in many applications. Failing to properly account for spatial autocorrelation may often lead to false conclusions. LÄS MER

4. 3. Methodological Studies on Models and Methods for Mixed-Effects Categorical Data Analysis

   Författare :Maria C. Kjellsson; Mats O. Karlsson; Siv Jönsson; Gordon Graham; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pharmacodynamics; Categorical data; Markov model; Modelling; NONMEM; NLMIXED; Laplace; Gaussian quadrature; Back-Step Method; Proportional odds model; Differential odds model;

   Sammanfattning : Effects of drugs are in clinical trials often measured on categorical scales. These measurements are increasingly being analyzed using mixed-effects logistic regression. However, the experience with such analyzes is limited and only a few models are used. LÄS MER

5. 4. Statistical methods in medical image estimation and sparse signal recovery

   Författare :Fekadu Lemessa Bayisa; Jun Yu; Ottmar Cronie; Henning Omre; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Computed tomography; magnetic resonance imaging; Gaussian mixture model; skew-Gaussian mixture model; hidden Markov random field; hidden Markov model; supervised statistical learning; synthetic CT images; pseudo-CT images; spike and slab prior; adaptive algorithm;

   Sammanfattning : This thesis presents work on methods for the estimation of computed tomography (CT) images from magnetic resonance (MR) images for a number of diagnostic and therapeutic workflows. The study also demonstrates sparse signal recovery method, which is an intermediate method for magnetic resonance image reconstruction. LÄS MER

7. 5. Model Based Speech Enhancement and Coding

   Författare :David Yuheng Zhao; Bastiaan Kleijn; Peter Kabal; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; statistical model; Gaussian mixture mdel GMM ; hidden Markov model HMM ; moise reduction; Telecommunication; Telekommunikation;

   Sammanfattning : In mobile speech communication, adverse conditions, such as noisy acoustic environments and unreliable network connections, may severely degrade the intelligibility and natural- ness of the received speech quality, and increase the listening effort. This thesis focuses on countermeasures based on statistical signal processing techniques. LÄS MER