Sökning: "MATHEMATICS Applied mathematics Mathematical statistics"

Visar resultat 21 - 25 av 64 avhandlingar innehållade orden MATHEMATICS Applied mathematics Mathematical statistics.

1. 21. Bayesian Phylogenetic Inference : Estimating Diversification Rates from Reconstructed Phylogenies

   Författare :Sebastian Höhna; Tom Britton; Fredrik Ronquist; Ziheng Yang; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Phylogenetics; Bayesian inference; Graphical Models; Birth-Death Process; Diversification; matematisk statistik; Mathematical Statistics;

   Sammanfattning : Phylogenetics is the study of the evolutionary relationship between species. Inference of phylogeny relies heavily on statistical models that have been extended and refined tremendously over the past years into very complex hierarchical models. LÄS MER

3. 22. On functions of a Wishart matrix and a normal vector with applications

   Författare :Edward Ngailo; Taras Bodnar; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematical Statistics; matematisk statistik;

   Sammanfattning : This thesis consists of two papers which take a critical look on functions of an inverse Wishart matrix and a Gaussian vector. In the first paper, the product expression, of which the inverse of the pooled estimator of the covariance matrix is inverse Wishart distributed and the difference of sample means is multivariate normally distributed, is investigated by exploring the distributional properties via a stochastic representation for both the finite sample case and the infinite sample case under the large-dimensional asymptotic regime. LÄS MER

4. 23. Towards a flexible statistical modelling by latent factors for evaluation of simulated responses to climate forcings

   Författare :Ekaterina Fetisova; Gudrun Brattström; Anders Moberg; Rolf Sundberg; Johan Lindström; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Confirmatory Factor Analysis; Measurement Error models; Structural Equation models; Wald confidence interval; Fieller confidence set; Climate model simulations; Climate forcings; Climate proxy data; Detection and Attribution; Mathematical Statistics; matematisk statistik;

   Sammanfattning : In this thesis, using the principles of confirmatory factor analysis (CFA) and the cause-effect concept associated with structural equation modelling (SEM), a new flexible statistical framework for evaluation of climate model simulations against observational data is suggested. The design of the framework also makes it possible to investigate the magnitude of the influence of different forcings on the temperature as well as to investigate a general causal latent structure of temperature data. LÄS MER

5. 24. Non-parametric methods for functional data

   Författare :Johan Strandberg; Sara Sjöstedt de Luna; Konrad Abramowicz; Lina Schelin; Charlotte Häger; Pedro Delicado; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; functional data analysis; testing; clustering; prediction; inference; bagging Voronoi strategy; kriging; dependency; matematisk statistik; Mathematical Statistics;

   Sammanfattning : In this thesis we develop and study non-parametric methods within three major areas of functional data analysis: testing, clustering and prediction. The thesis consists of an introduction to the field, a presentation and discussion of the three areas, and six papers. LÄS MER

7. 25. Large deviation techniques applied to three questions of when

   Författare :Ola Hammarlid; Anders Martin-Löf; Ingmar Kaj; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Large deviations; first passage time; stopping time; rate function; convex barrier; fallacy of large numbers; utility function; insurance; ruin; variable premium; generalized Ornstein-Uhlenbeck process; Mathematical statistics; Matematisk statistik;

   Sammanfattning : Large deviation techniques are used to solve three problems; when is a distant convex barrier passed, when to accept a sequence of gambles and when is the time of ruin. This work is the collection of four papers. LÄS MER