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Visar resultat 1 - 5 av 21 avhandlingar som matchar ovanstående sökkriterier.
1. Stochastic Models in Phylogenetic Comparative Methods: Analytical Properties and Parameter Estimation
Sammanfattning : Phylogenetic comparative methods are well established tools for using inter-species variation to analyse phenotypic evolution and adaptation. They are generally hampered, however, by predominantly univariate approaches and failure to include uncertainty and measurement error in the phylogeny as well as the measured traits. LÄS MER
2. Some Extensions of Fractional Ornstein-Uhlenbeck Model : Arbitrage and Other Applications
Sammanfattning : This doctoral thesis endeavors to extend probability and statistical models using stochastic differential equations. The described models capture essential features from data that are not explained by classical diffusion models driven by Brownian motion.New results obtained by the author are presented in five articles. LÄS MER
3. Multivariate Aspects of Phylogenetic Comparative Methods
Sammanfattning : his thesis concerns multivariate phylogenetic comparative methods. We investigate two aspects of them. The first is the bias caused by measurement error in regression studies of comparative data. We calculate the formula for the bias and show how to correct for it. LÄS MER
4. A Differentiable Approach to Stochastic Differential Equations : the Smoluchowski Limit Revisited
Sammanfattning : In this thesis we generalize results by Smoluchowski [43], Chandrasekhar[6], Kramers, and Nelson [30]. Their aim is to construct Brownian motion as a limit of stochastic processes with differentiable sample paths by exploiting a scaling limit which is a particular type of averaging studied by Papanicolao [35]. LÄS MER
5. Nelson-type Limits for α-Stable Lévy Processes
Sammanfattning : Brownian motion has met growing interest in mathematics, physics and particularly in finance since it was introduced in the beginning of the twentieth century. Stochastic processes generalizing Brownian motion have influenced many research fields theoretically and practically. LÄS MER