Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"linear mixed effect models"”.
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Multivariate muti-level non-linear mixed-effect models and their application to the modeling of drug-concentration time curves
… the techniques involved in the fitting of nonlinear mixed effect (NLME) models. In particular, it looks at the application of these techniques to the analysis of concentration-time data for the aforementioned antimalarial compounds, and details the necessary extensions to the basic modeling …
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The Importance Of Surface Mining As A Landscape Variable In Shaping Wild Bee Communities In Central Appalachian Forests
… is common. Data was analyzed using generalized linear mixed-effect models to detect the most important landscape scale variables, including mining, in shaping bee communities. Bee species richness was significantly lower on sites that contained surface mines, but abundance was similar between …
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A GLMM analysis of data from the Sinovuyo Caring Families Program (SCFP)
… used to impute missing information. Generalized linear Mixed Effect Models (GLMMs) were used to assess the impact of the intervention program on the responses, adjusted for possible confounding variables. These summed scores were often right skewed with zero-inflation. All the effects (fixed and …
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Nonparametric testing for random effects in mixed effects models based on the piecewise linear interpolate of the log characteristic function
Traditional linear mixed effect models assume the distributions of the random effects and errors follow normal distribution with mean zero and homoscedastic variance sigma square. This thesis presents a new nonparametric testing approach for normality for the random effects distribution based on …
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Longitudinal analysis of Brain Metabolite levels for HIV infected Children from ages five to eleven
… Resonance Spectroscopy (MRS). We used univariate linear mixed effect models to identify independent profiles of the metabolites measured in each region of the brain. To explore the metabolite trends in a multivariate setting we generated multilevel mixed effects models, and correlated response …
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Modelling Multivariate Nonlinear Vaccine Induced Immune Responses
Interpretable statistical models for multivariate vaccine induced immune response data are important as they provide a rigorous means of deciding which vaccine candidates should be advanced in the clinical trials process. We consider applications of several different statistical models to a vaccine …
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The Effects of Internalized Homonegativity, Outness, and Depression on Sexual Risk Prevention Behaviors of Minority Men Who Have Sex With Men
… study sought to provide an understanding of the effect of outness, homonegativity, and depression on the odds of engaging in treatment as prevention (TaSP) overtime using generalized linear mixed effect models. In addition, the linear mixed effect model was employed to determine if there were …
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Food Supply Early in the Plant Growing Season: Influences from Elk Abundance and Precipitation
… 7 sectors, 2-10 hectares in size. I compared linear mixed effect models using Aikaike Information Criterion to determine whether elk abundance and total precipitation had an additive or multiplicative influence on the herbivore food supply. The selected model included elk abundance and …
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Longitudinal analysis of platelet count data
… National Blood Service (SANBS), I employed linear mixed-effect models to analyse platelet count trajectories and latent class mixed models to uncover donor clusters with distinct patterns. The findings reveal evidence of seasonal fluctuations in platelet counts, with highs in winter months, …
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Statistical modelling to determine the influence of vaccine dose and prior Mycobacterium tuberculosis exposure on antigen-specific T cell responses
This dissertation investigates the effects of two subunit vaccines H1:IC31 and H56:IC31 as well as prior M.tb sensitization on the immune responses of three cohorts of South African adolescents and adults. The primary outcomes are frequencies of antigen-specific CD4 T cells expressing different …
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Wintering Reddish Egret (Egretta Rufescens) Foraging Response To Environmental Variability On The Southern Texas Gulf Coast
… Using negative binomial and logistic generalized linear mixed effect models of my count data and multiple environmental variables, I found increasing wind speed and an easterly wind direction had negative effect on the presence of foraging Reddish Egrets in the study area, while a westerly wind …
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Optimization methods for parameter identifications in settings with only partial knowledge
… prior knowledge into machine learning models. In the first project, a universal feature selection method for linear mixed-effect models is developed. Namely, Sparse Relaxed Regularized Regression (SR3) is extended to the case of Linear Mixed-Effect (LME) likelihoods, and we prove that …
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Assessing the Quality of Synthetic Speech when using Enhanced Speech as Training Data
… remains under-explored. In particular, the effectiveness of using enhanced speech to train a speech synthesis model is still relatively unknown. This thesis investigates the effects of using enhanced speech to train a speech synthesis model on the overall quality of the synthesised speech, …
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Analysis of Multivariate Longitudinal Data Using Structural Equation Modeling
<p>Structural equation models represent the convergence of relatively independent research traditions in psychology, psychiatry, econometrics, and biometrics. It is a multivariate technique which combines the different statistical methodologies, such as regression analysis, simultaneous equations, …
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Resurrection ecology of invertebrates in temporary wetlands in the Cape Floristic region: effects of urbanisation and fire
… methods (during September and October 2016). The effects of fire were tested, on hatching success by staging vegetation fires over the collected soil samples for five temporary wetland areas in the same region. Mann-Whitney U tests were used to test differences in abundances between treatments, …
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Habitat selection and spatial personalities of Belizean white-tailed deer
… viable wildlife populations. Therefore, movement models have emerged as important tools for wildlife management and conservation. However, consistent individual variation in movement behavior (e.g., habitat selection) – referred to as spatial personality – may have important ramifications for …
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The impact of social deprivation on development and progression of diabetic kidney disease
… a tertiary referral centre in Ireland. I used linear mixed effect models to calculate rate of decline in renal function using longitudinal estimated glomerular filtration rate (eGFR) data. I examined baseline clinical variables such as diabetes duration, smoking status, body mass index (BMI), …
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Effects of HIV on longitudinal development of the fronto-striatal resting state networks in children from 7 to 11 years
… conducted a longitudinal analysis to examine the effects of age and HIV on functional connectivity (FC) between the BG and the frontal cortex. Rs-fMRI data were collected at ages 7, 9 and 11 from children with perinatal HIV (CPHIV) who were part of the Children with HIV Early AntiRetroviral (CHER) …
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Moving towards an evidence informed approach to talent identification and development in Scottish soccer long term athlete development pathways.
… Retrospective analysis was conducted utilising linear mixed effect models across physical performance parameters (papers I, III and IV), Pearson's Chi squared and odd's ratios on relative age impacts (papers II and III) and least absolute shrinkage and selection operator (LASSO) logistic …
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Characterizing Human Driving Behavior Through an Analysis of Naturalistic Driving Data
… The second major contribution is quantifying the effect of several factors that influence acceleration behavior. The rate of mild to harsh acceleration epochs was modeled using negative binomial distribution-based generalized linear mixed effect models. Roadway speed category, driver age, driver …
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