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- Adversarial Decision Making (1)
- Alternative tobacco products; environment; genes; nicotine; tobacco; young adulthood (1)
- Charge (1)
- Condensation (1)
- Correlated AUCs (1)
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- Counterterrorism Application (1)
- DNA (1)
- Dimer (1)
- Experimental design (1)
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- Group screening (1)
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- Longitudinal (1)
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- Nonparametric Regression; Penalized Spline; Poisson; Profile Monitoring; Semi-parametric Regression (1)
- Optimization solvers (1)
- Parameter tuning (1)
- Pfaffian (1)
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- Risk Matrices (1)
- Structural Components (1)
- Type 1 Error (1)
- U-statistics (1)
- Wavelets (1)
- Weighted Quantile Sum Regression (1)
Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Weighted Quantile Sum Regression For Analyzing Correlated Predictors Acting Through A Mediation Pathway On A Biological Outcome, Bhanu M. Evani
Weighted Quantile Sum Regression For Analyzing Correlated Predictors Acting Through A Mediation Pathway On A Biological Outcome, Bhanu M. Evani
Theses and Dissertations
Abstract
Weighted Quantile Sum Regression for Analyzing Correlated Predictors Acting Through a Mediation Pathway on a Biological Outcome
By
Bhanu M. Evani, Ph.D.
A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University.
Virginia Commonwealth University, 2017.
Major Director: Robert A. Perera, Asst. Professor, Department of Biostatistics
This work examines mediated effects of a set of correlated predictors using the recently developed Weighted Quantile Sum (WQS) regression method. Traditionally, mediation analysis has been conducted using the multiple regression method, first proposed by Baron and Kenny (1986), which has since …
A Multi-Method Exploration Of The Genetic And Environmental Risks Contributing To Tobacco Use Behaviors In Young Adulthood, Elizabeth K. Do
A Multi-Method Exploration Of The Genetic And Environmental Risks Contributing To Tobacco Use Behaviors In Young Adulthood, Elizabeth K. Do
Theses and Dissertations
Tobacco use remains the leading preventable cause of morbidity and mortality in both the United States and worldwide. Twin and family studies have demonstrated that both genetic and environmental factors are important contributors to tobacco use behaviors. Understanding how genes, the environment, and their interactions is critical to the development of public health interventions that focus on the reduction of tobacco related morbidity and mortality. However, few studies have examined the transition from adolescent to young adulthood – the time when many individuals are experimenting with and developing patterns of tobacco use. This dissertation thesis seeks to provide a comprehensive …
Comparing The Structural Components Variance Estimator And U-Statistics Variance Estimator When Assessing The Difference Between Correlated Aucs With Finite Samples, Anna L. Bosse
Theses and Dissertations
Introduction: The structural components variance estimator proposed by DeLong et al. (1988) is a popular approach used when comparing two correlated AUCs. However, this variance estimator is biased and could be problematic with small sample sizes.
Methods: A U-statistics based variance estimator approach is presented and compared with the structural components variance estimator through a large-scale simulation study under different finite-sample size configurations.
Results: The U-statistics variance estimator was unbiased for the true variance of the difference between correlated AUCs regardless of the sample size and had lower RMSE than the structural components variance estimator, providing better type 1 error …
The Generalized Monotone Incremental Forward Stagewise Method For Modeling Longitudinal, Clustered, And Overdispersed Count Data: Application Predicting Nuclear Bud And Micronuclei Frequencies, Rebecca Lehman
Theses and Dissertations
With the influx of high-dimensional data there is an immediate need for statistical methods that are able to handle situations when the number of predictors greatly exceeds the number of samples. One such area of growth is in examining how environmental exposures to toxins impact the body long term. The cytokinesis-block micronucleus assay can measure the genotoxic effect of exposure as a count outcome. To investigate potential biomarkers, high-throughput assays that assess gene expression and methylation have been developed. It is of interest to identify biomarkers or molecular features that are associated with elevated micronuclei (MN) or nuclear bud (Nbud) …
Parametric, Nonparametric And Semiparametric Approaches In Profile Monitoring Of Poisson Data, Sepehr Piri
Parametric, Nonparametric And Semiparametric Approaches In Profile Monitoring Of Poisson Data, Sepehr Piri
Theses and Dissertations
Profile monitoring is a relatively new approach in quality control best used when the process data follow a profile (or curve). The majority of previous studies in profile monitoring focused on the parametric modeling of either linear or nonlinear profiles under the assumption of the correct model specification. Our work considers those cases where the parametric model for the family of profiles is unknown or, at least uncertain. Consequently, we consider monitoring Poisson profiles via three methods, a nonparametric (NP) method using penalized splines, a nonparametric (NP) method using wavelets and a semi parametric (SP) procedure that combines both parametric …
Tuning Optimization Software Parameters For Mixed Integer Programming Problems, Toni P. Sorrell
Tuning Optimization Software Parameters For Mixed Integer Programming Problems, Toni P. Sorrell
Theses and Dissertations
The tuning of optimization software is of key interest to researchers solving mixed integer programming (MIP) problems. The efficiency of the optimization software can be greatly impacted by the solver’s parameter settings and the structure of the MIP. A designed experiment approach is used to fit a statistical model that would suggest settings of the parameters that provided the largest reduction in the primal integral metric. Tuning exemplars of six and 59 factors (parameters) of optimization software, experimentation takes place on three classes of MIPs: survivable fixed telecommunication network design, a formulation of the support vector machine with the ramp …
Adversarial Decision Making In Counterterrorism Applications, Dogucan Mazicioglu
Adversarial Decision Making In Counterterrorism Applications, Dogucan Mazicioglu
Theses and Dissertations
Our main objective is to improve decision making in counterterrorism applications by implementing expected utility for prescriptive decision making and prospect theory for descriptive modeling. The areas that we aim to improve are behavioral modeling of adversaries with multi objectives in counterterrorism applications and incorporating risk attitudes of decision makers to risk matrices in assessing risk within an adversarial counterterrorism framework. Traditionally, counterterrorism applications have been approached on a single attribute basis. We utilize a multi-attribute prospect theory approach to more realistically model the attacker’s behavior, while using expected utility theory to prescribe the appropriate actions to the defender. We …
Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker Iii
Application Of The Fisher Dimer Model To Dna Condensation, John C. Baker Iii
Theses and Dissertations
This paper considers the statistical mechanics occupation of the edge of a single helix of DNA by simple polymers. Using Fisher's exact closed form solution for dimers on a two-dimensional lattice, a one-dimensional lattice is created mathematically that is occupied by dimers, monomers, and holes. The free energy, entropy, average occupation, and total charge on the lattice are found through the usual statistical methods. The results demonstrate the charge inversion required for a DNA helix to undergo DNA condensation.