Sökning: "missing not at random"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden missing not at random.

1. 1. Methodology for Handling Missing Data in Nonlinear Mixed Effects Modelling

   Författare :Åsa M. Johansson; Mats O. Karlsson; Andrew C. Hooker; Leon Aarons; Uppsala universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Pharmacometrics; population models; censored observations; missing covariates; missing dependent variable; missing data mechanism; missing completely at random MCAR ; missing at random MAR ; missing not at random MNAR ; estimation algorithms; Pharmaceutical Science; Farmaceutisk vetenskap;

   Sammanfattning : To obtain a better understanding of the pharmacokinetic and/or pharmacodynamic characteristics of an investigated treatment, clinical data is often analysed with nonlinear mixed effects modelling. The developed models can be used to design future clinical trials or to guide individualised drug treatment. LÄS MER

3. 2. Uncertainty intervals and sensitivity analysis for missing data

   Författare :Minna Genbäck; Xavier de Luna; Elena Stanghellini; Arvid Sjölander; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; missing data; missing not at random; non-ignorable; set identification; uncertainty intervals; sensitivity analysis; self reported health; average causal effect; average causal effect on the treated; mixed-effects models; Statistics; statistik;

   Sammanfattning : In this thesis we develop methods for dealing with missing data in a univariate response variable when estimating regression parameters. Missing outcome data is a problem in a number of applications, one of which is follow-up studies. LÄS MER

4. 3. Numerical methods for load and response prediction for use in acoustic fatigue

   Författare :Johan Nilsson; Byggnadsmekanik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Acoustic fatigue; Sonic fatigue; Computational Fluid Dynamics; Large Eddy Simulation; Finite Element Method; Random response analysis; Separated flow; High Re; Backward-facing step; Fence flow; Aircraft; Proper Orthogonal Decomposition; Acoustic fatigue; Sonic fatigue; Computational Fluid Dynamics; Large Eddy Simulation; Finite Element Method; Random response analysis; Separated flow; High Re; Backward-facing step; Fence flow; Aircraft; Proper Orthogonal Decomposition;

   Sammanfattning : Acoustic fatigue can occur in structural elements of an aircraft exposed to very high sound pressures. To deal with acoustic fatigue, mainly empirical methods have been applied and often late in the design phase. Current design guidelines have three main limitations. First, they do not say anything about the load intensities. LÄS MER

5. 4. Finding fitness : empirical and theoretical explorations of inferring fitness effects from population-level SNP data

   Författare :Bea Angelica Andersson; Xiao-Ru Wang; Åke Brännström; Tanja Slotte; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; distribution of fitness effects; site frequency spectra; missing data filtering; downsampling; imputation; sample size; population structure; inbreeding; selfing; homozygosity; Arabidopsis; Pinus; DFE-alpha; SLiM; population genomics; adaptation; biology; biologi; evolutionär genetik; evolutionary genetics; populationsbiologi; Population Biology; molekylärbiologi; Molecular Biology; Genetics; genetik;

   Sammanfattning : The distribution of fitness effects (DFE) describes the likelihood that a new mutation has a specific effect on the fitness of an individual in a given population. The shape of the DFE is a result of several factors such as population size, mating system and selective environment, and can in turn influence the evolutionary potential of a species. LÄS MER

7. 5. The Shortened Dental Arch (SDA) concept and Swedish general dental practitioners : attitudes and prosthodontic decision-making

   Författare :Eva-Karin Korduner; Malmö högskola; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Shortened dental arch; Decision-making; qualitatative research; compromised molars; dentistry; prosthodontic decision-making; Attitudes;

   Sammanfattning : 10ABSTRACTA Shortened Dental Arch (SDA) is defined as a dentition where most posterior teeth are missing. The SDA concept, described by Käyser and co-workers in the 1980s, was developed mainly for elderly and high risk-patients, those with poor general health and those with accumulation of dental problems. LÄS MER