Sökning: "variance"

Visar resultat 1 - 5 av 880 avhandlingar innehållade ordet variance.

1. 1. On Degree Variance in Random Graphs

   Författare :Jan Hagberg; Ove Frank; Tom A.B. Snijders; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Degree Sequences; Uniform Random Graphs; Bernoulli Graphs; Degree Moments; Degree Statistics; Degree Variance; Gamma Approximation; Centrality Testing; Integer Sequences; Statistics; Statistik;

   Sammanfattning : This thesis is concerned with degree moments and degree variance in random graphs. The degree of vertex i in a graph is the number of edges incident to vertex i.In the first paper, degree moments and functions of degree moments are investigated for three random graph models. LÄS MER

3. 2. Novel Statistical Methods in Quantitative Genetics : Modeling Genetic Variance for Quantitative Trait Loci Mapping and Genomic Evaluation

   Författare :Xia Shen; Örjan Carlborg; Lars Rönnegård; William Hill; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; statistical genetics; quantitative trait loci; genome-wide association study; genomic selection; genetic variance; hierarchical generalized linear model; linear mixed model; random effect; heteroscedastic effects model; variance-controlling genes; Complex Systems – Microdata Analysis;

   Sammanfattning : This thesis develops and evaluates statistical methods for different types of genetic analyses, including quantitative trait loci (QTL) analysis, genome-wide association study (GWAS), and genomic evaluation. The main contribution of the thesis is to provide novel insights in modeling genetic variance, especially via random effects models. LÄS MER

4. 3. Mean-Variance Portfolio Optimization : Eigendecomposition-Based Methods

   Författare :Fred Mayambala; Torbjörn Larsson; Elina Rönnberg; Juma Kasozi; Ann-Brith Strömberg; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Modern portfolio theory is about determining how to distribute capital among available securities such that, for a given level of risk, the expected return is maximized, or for a given level of return, the associated risk is minimized. In the pioneering work of Markowitz in 1952, variance was used as a measure of risk, which gave rise to the wellknown mean-variance portfolio optimization model. LÄS MER

5. 4. Variance Reduction in Analytical Chemistry : New Numerical Methods in Chemometrics and Molecular Simulation

   Författare :K. Magnus Åberg; Sven P. Jacobsson; Richard G. Brereton; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; chemometrics; pulse-coupled neural networks; peak alignment; class separability; molecular dynamics; Monte Carlo; expanded ensembles; free energy; Analytical chemistry; Analytisk kemi;

   Sammanfattning : This thesis is based on five papers addressing variance reduction in different ways. The papers have in common that they all present new numerical methods. LÄS MER

7. 5. Estimating Probability Distribution by doing Computer Experiments

   Författare :Gunnar Kjell; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computer simulations; seismic verification; response spectrum prediction; stratified sampling; latin hypercube sampling; variance reduction; variance estimation; seismic verification;

   Sammanfattning : In almost every field of engineering, advanced computer programs are used. In many cases only the probability distributions of the input variables to the programs are known. Sometimes stochastic processes are used as input, for example if the stresses in a construction due to an earthquake are to be calculated. LÄS MER