Digital Commons Network^™

Variable Selection For Complex Data With Sparsity: An Application In Gwas, Tianhui Wei

All Dissertations

In this dissertation, we investigate the limitations of several methods that have been proposed for variable selection in recent decades, and in particular we explore how these limitations arise in genome-wide association studies (GWAS). Three often discussed categories of methods include ordinary least squares, penalized regression, and Bayesian approaches, but while there have been efforts in the past to apply these techniques to GWAS, it remained unclear whether or not one approach was superior to the others, or if certain scenarios might favor a given method. In this research, our results from two real data sets reveal that the three …

Wetting Of Bio-Inspired Complexly-Shaped Fibers And Channels, Chengqi Zhang

All Dissertations

This Dissertation is centered on studying the wetting of complexly-shaped fibers and channels which is inspired by the Lepidopteran proboscis. From materials science and engineering standpoint, the Lepidopteran proboscis is a multifunctional microfluidic device. The unique materials organization, morphology, structure, and surface properties of the proboscis allows the Lepidopterans to feed on various food sources from highly viscous to very thin liquids while keeping its surface clean. Thus, the study on the proboscis wetting phenomena has drawn great interests of materials scientists and engineers. The shape of the Lepidopteran proboscis has a very special design combining complexly-shaped fibers and channels. …

Language And Literacy In A Head Start Preschool: Understanding Practice To Inform Theory And Improve Outcomes, M. Deanna Ramey

All Dissertations

Head Start is a federally funded program providing comprehensive social and early education services to children from low-income households and their families. Seeking to boost outcomes of Head Start students, in 1998 Congress amended Head Start's statement of purpose, specifying school readiness as the program's top priority. This mission change necessitated that Head Start, long-focused on promoting social competence, shift attention to a new concern—supporting children's development in cognitive domains such as math and literacy. Data suggest that though some progress has been made, Head Start preschoolers still lag behind their peer group in assessments of early math, language, and …

Exploring Underrepresented Doctoral Students' Conceptualizations Of The Student-Advisor Relationship In Chemistry, Aubrie Lynn Pfirman

All Dissertations

While it is typical for doctoral students in the sciences to have a faculty advisor, not all students can name a mentor for their doctoral journey. Noted as the most important factor in determining a student's success and satisfaction in graduate school, the student-advisor relationship is an important area for expanded study and analysis to fill in the gaps in understanding of our doctoral education system. This study details the various ways in which underrepresented chemistry doctoral students view and perceive their relationships with their faculty advisor. I used purposeful sampling to select 16 underrepresented doctoral chemistry students at public, …

On Some Conjectures In Additive Number Theory, Huixi Li

All Dissertations

In the first part of the thesis we prove that every sufficiently large odd integer can be written as a sum of a prime and 2 times a product of at most two distinct odd primes. Together with Chen's theorem and Ross's observation, we know every sufficiently large integer can be written as a sum of a prime and a square-free number with at most three prime divisors, which improves a theorem by Estermann that every sufficiently large integer can be written as a sum of a prime and a square-free number. In the second part of the thesis we …

Model Predictive Control Of Modern High-Degree-Of-Freedom Turbocharged Spark Ignited Engines With External Cooled Egr, Rohit Vishvanath Koli

All Dissertations

The efficiency of modern downsized SI engines has been significantly improved using cooled Low-Pressure Exhaust Gas Recirculation, Turbocharging and Variable Valve Timing actuation. Control of these sub-systems is challenging due to their inter-dependence and the increased number of actuators associated with engine control. Much research has been done on developing algorithms which improve the transient turbocharged engine response without affecting fuel-economy. With the addition of newer technologies like external cooled EGR the control complexity has increased exponentially. This research proposes a methodology to evaluate the ability of a Model Predictive Controller to coordinate engine and air-path actuators simultaneously. A semi-physical …

Generalizations Of Permutation Statistics To Words And Labeled Forests, Amy Christine Grady

All Dissertations

A classical result of MacMahon shows the equidistribution of the major index and inversion number over the symmetric groups. Since then, these statistics have been generalized in many ways, and many new permutation statistics have been defined, which are related to the major index and inversion number in may interesting ways. In this dissertation we study generalizations of some newer statistics over words and labeled forests.

Foata and Zeilberger defined the graphical major index, majU , and the graphical inversion index, invU , for words over the alphabet {1, . . . , n}. In this dissertation we define a …

Modding The Apocalypse: (Re)Making Videogames As Post-Structuralist Free Play, Samuel Jackson Fuller

All Dissertations

This dissertation is about seeing videogames, and videogame design, through the lens of Gregory Ulmer"™s electracy apparatus theory. Videogame modding is emphasized an electrate approach to intervening in existing media. Mods have the potential to make potent rhetorical arguments, but they are little-understood in the field of rhet-comp, and there are numerous obstacles to carving a space for them in academic curricula; nevertheless, they are an increasingly common form of participatory engagement that make use of a broad digital skillset. Modders fit into Gregory Ulmer"™s electracy apparatus as egents"”agents of change in the Internet age"”and their playful appropriation of objects …

Mathematical Models And Algorithms For Network Flow Problems Arising In Wireless Sensor Network Applications, Robert M. Curry

All Dissertations

We examine multiple variations on two classical network flow problems, the maximum flow and minimum-cost flow problems. These two problems are well-studied within the optimization community, and many models and algorithms have been presented for their solution. Due to the unique characteristics of the problems we consider, existing approaches cannot be directly applied. The problem variations we examine commonly arise in wireless sensor network (WSN) applications. A WSN consists of a set of sensors and collection sinks that gather and analyze environmental conditions. In addition to providing a taxonomy of relevant literature, we present mathematical programming models and algorithms for …

Some Interesting Effects Of High-Frequency Non-Resonant Harmonic Excitations On The Slow Response Of Duffing Oscillators, Abdraouf Abusoua

All Dissertations

This dissertation investigates the response of Duffing oscillators to bi-harmonic ex-citations consisting of a soft resonant component and a hard high-frequency non-resonant component. To this end, the dissertation uses approximate analytical solutions, numerical simulations, and an especially-designed experimental module to detail the influence of non-resonant excitation on the resonant response for oscillators with symmetric/asymmetric, mono and bi-stable potential energy functions. For mono-stable Duffing oscillators, we demonstrate that the high-frequency excitation has a substantial influence on the shape of the potential energy function associated with the slow dynamics. In specific, we show that the hard excitation stiffens the slow response for …

A Molecular Dynamics Study Of The Cellulose-Graphene Oxide Nanocomposites: The Interface Effects, Qian Mao

All Dissertations

Cellulose has gained increasing attention due to its abundance and renewability. Obtained through a strong acid hydrolysis treatment of cellulose microfibrils, cellulose nanocrystals (CNCs) stand out among all hierarchical cellulose structures with appealing mechanical and optical properties that have been utilized as a reinforcing nanomaterial for the advanced material design. The cellulose nanocrystal graphene oxide (CNC-GO) nanocomposite film has been developed and successfully applied in portable and bendable sensing optoelectronics, energy storage and electromagnetic pulse protection devices. New material phenomena have been observed through experimental characterizations, but they lack fundamental understanding due to the experimental limitations in nanoscale. Therefore, a …

A Controls-Oriented Approach For Modeling Professional Drivers During Ultra-High Performance Maneuvers, Jeffery Ryan Anderson

All Dissertations

In the study of vehicle dynamics and controls, modeling ultra-high performance maneuvers (i.e., minimum-time vehicle maneuvering) is a fascinating problem that explores the boundaries of capabilities for a human controlling a machine. Professional human drivers are still considered the benchmark for controlling a vehicle during these limit handling maneuvers. Different drivers possess unique driving styles, i.e. preferences and tendencies in their local decisions and corresponding inputs to the vehicle. These differences in the driving style among professional drivers or sets of drivers are duly considered in the vehicle development process for component selection and system tuning to push the limits …

Coupled Hydrological-Geotechnical Model For Determinine Bearing Capacity And Elastic Settlement Of Foundations, Vahidreza Mahmoudabadi Arani

All Dissertations

This dissertation presents a coupled hydrological-geotechnical framework to investigate the performance of shallow and deep foundations under hydrological events such as heavy rainfall and drought. The variation in performance of foundation, interface between the structure and ground surface, is caused by the uncertainties associated with not only the geotechnical parameters but also the hydrological parameters that include intensity and duration of hydrological events and water table depth. The impact of such hydrological events significantly alters the performance of foundations by changing the soil strength and stiffness parameters of subsurface soil which may lead to foundation failures. Such failures can cause …

Efficient And Accurate Splitting Methods For Flow Problems, Mengying Xiao

All Dissertations

No abstract provided.

Persuasive Intelligence: On The Construction Of Rhetor-Ethical Cognitive Machines, Nathan D. Riggs

All Dissertations

This work concerns the rhetorical and moral agency of machines, offering paths forward in machine ethics as well as problematizing the issue through the development and use of an interdisciplinary framework informed by rhetoric, philosophy of mind, media studies and historical narrative. I argue that cognitive machines of the past as well as those today, such as rapidly improving autonomous vehicles, are unable to make moral decisions themselves foremost because a moral agent must first be a rhetorical agent, capable of persuading and of being persuaded. I show that current machines, artificially intelligent or otherwise, and especially digital computers, are …

Plutonium In The Presence Of Natural Organic Ligands: Sorption Kinetics, Surface Complex Stability, And Subsurface Transport, Jennifer Christine Wong

All Dissertations

This work investigated aging of plutonium (Pu) on the surface of goethite, the effect of natural organic ligands on the enhancement of Pu desorption and mobility, and Pu transport in a natural soil. Because adsorption of Pu is frequently observed to be initially rapid followed by slower adsorption over days to weeks, Pu may undergo aging, where a surface process following initial adsorption causes a change in Pu state over time. Pu uptake which exhibits fast and slow sorption phases has been successfully modeled using a multisite model where sorbed Pu is represented as two compartments with different rates of …

Probabilistic Assessment Of Soil Liquefaction Potential And Mitigation, Mengfen Shen

All Dissertations

It has been well observed and reported that much of the great losses in past earthquakes, such as the 2011 Tohoku earthquake and the 2010-2011 Canterbury earthquake, were attributed to soil liquefaction and the associated ground deformation. Thus, any relevant research that contributes to the worldwide efforts to assess and mitigate liquefaction hazards is considered timely and worthwhile. This dissertation is aimed at addressing two aspects of liquefaction research: (1) improving the existing probabilistic methods for both location-specific and areal liquefaction potential evaluation, (2) creating visualization-based procedure for assessing the effectiveness of dynamic compaction in the liquefaction hazards mitigation. Both …

Modeling And Performance Analysis Of A Sloshing Ferrofluid Based Electromagnetic Energy Harvester, Qi Liu

All Dissertations

Computational modeling and performance analysis are carried out for a ferrofluid based electromagnetic energy harvester which converts ambient vibratory energy into electromotive force through sloshing motion of a ferrofluid. The system consists of a tank partially filled with ferrofluid, magnets placed on the opposite sides of the tank and a copper coil wound around the tank. In the presence of an external magnetic field, magnetic dipoles in the ferrofluid rotate and produce a net magnetic moment aligned in the direction of the field. When the device is subjected to an external excitation, the ferrofluid in the tank undergoes a sloshing …

Some Models For Count Time Series, Yisu Jia

All Dissertations

There has been growing interest in modeling stationary series that have discrete marginal distributions. Count series arise when describing storm numbers, accidents, wins by a sports team, disease cases, etc. The first count time series model introduced in this paper is the superpositioning methods. It have proven useful in devising stationary count time series having Poisson and binomial marginal distributions. Here, properties of this model class are established and the basic idea is developed. Specifically, we show how to construct stationary series with binomial, Poisson, and negative binomial marginal distributions; other marginal distributions are possible. A second model class for …

Using Multinomial Regression To Examine The Mediating Effect Of Parental Knowledge About College Tuition On Postsecondary Attendance Expectations, Chuck Knepfle

All Dissertations

The purpose of the following paper is to utilize multinomial regression to study the effect of various demographic and family characteristic variables on both the parental expectations of future postsecondary degree attainment and the parental estimates of college costs. I also explore the effect of college cost estimates as a mediating factor on the parents' expectation of the students' degree attainment. There is significant existing research on college costs, affordability, financial aid, and educational attainment for the various demographic factors found in this study. The missing piece in both the literature and overall understanding of the problem lies in the …

Analysis Of Time-Series Data Embedded In An Experiment Design, Yinggu Bao

All Dissertations

In this dissertation, our objective is to determine the impact of air temperature and rainfall on soil temperature with proximity to sidewalk. First, we concerned the many missing values in our data set. Some traditional and commonly used methods of imputation are introduced and then applied to the data set. Then, we concerned the relationships among the soil temperature, air temperature, and rainfall data. Since these data are time series, Granger Causality is used to estimate the relationships. Lastly, we focused on the analysis of the actual study design. The four distances are considered as treatments and the three locations …

Clemson Trustees Minutes, 2018 July 20, Clemson University Board Of Trustees

Minutes

No abstract provided.

Rapid Screening Of Ellagitannins In Natural Sources Via Targeted Reporter Ion Triggered Tandem Mass Spectrometry, Jeremiah J. Bowers, Harsha P. Gunawardena, Anaëlle Cornu, Ashwini S. Narvekar, Antoine Richieu, Denis Deffieux, Stéphane Quideau, Nishanth Tharayil

Publications

Complex biomolecules present in their natural sources have been difficult to analyze using traditional analytical approaches. Ultrahigh-performance liquid chromatography (UHPLC-MS/MS) methods have the potential to enhance the discovery of a less well characterized and challenging class of biomolecules in plants, the ellagitannins. We present an approach that allows for the screening of ellagitannins by employing higher energy collision dissociation (HCD) to generate reporter ions for classification and collision-induced dissociation (CID) to generate unique fragmentation spectra for isomeric variants of previously unreported species. Ellagitannin anions efficiently form three characteristic reporter ions after HCD fragmentation that allows for the classification of unknown …

Light And Death: Figuration In Spenser, Kepler, Donne, Milton / Judith H. Anderson, Timothy Duffy

Early Modern Culture

No abstract provided.

In The Anthropocene Air: Deleuze's Encounter With Shakespeare, Steven Swarbrick

Early Modern Culture

No abstract provided.

Evaluation Of Parameters Affecting The Performance Of Lipase Transesterification Using Cottonseed Oil, Stanley Terrell Anderson

All Theses

Eversa Transform® was used with crude and glandless cottonseed oil to evaluate the key parameters in its performance. Eversa is one of the newer products produced by Novozymes A/S (Copenhagen, Denmark) and has attracted much industry use. Cottonseed oil is a fringe oil in the biodiesel production market that was not tested with Eversa Transform® to our knowledge. The goal of this research was to see which dominant parameters were the most influential on the performance of Eversa. After careful review of literature, temperature, enzyme amount and water amount were the most consistently manipulated variables to produce more optimal results. …

A Meta-Analysis Of The Enantioselectvie Dechlorination Of Select Chiral Polcychlorinated Biphenyls (Pcbs), Eric Boley

All Theses

A meta-analysis was performed to investigate nonracemic enantiomer fraction (EF) levels of chiral polychlorinated biphenyls (PCBs) found in various media across the world. Nonracemic EF levels are those determined to be statistically different than 0.5. The existing body of knowledge from the literature provided the necessary data to determine via meta-analysis a true average EF for five selected congeners, 91, 95, 132, 136, and 149. A thorough literature search was conducted to find relevant articles that contained sampling data from lab and field studies for chiral PCBs. A database was constructed to organize the sampling data obtained from the literature. …

Rendering 3d Fractals, Zachary Shore

All Theses

This thesis presents Cackle, a GPU accelerated path tracer for rendering 3D fractals. It is comprised of a GLSL viewer for real-time visualization and a series of CUDA kernels for offline rendering. Cackle supports both point lights and environment lights for lighting. A Cook-Torrance shading model was implemented for materials. The results are demonstrated with a series of renders and a discussion on artistic scene selection and lighting.

The Effect Of Hot Fill And Hold Processing On The Performance Of Multilayer Packaging Films, Meredith Leigh Johnson

All Theses

Heat transfer in thermal processing is crucial to ensure all parts of a product are sufficiently treated to achieve commercial sterility without unacceptable loss of quality. Optimizing pasteurization methods is recommended to preserve quality attributes such as color, texture, and flavor while maintaining food safety integrity. This research evaluated the temperature variability in pouches during a hot fill and hold process and the effect of those identified differences on color quality of a tomato based food simulant. The performance of multilayer films for pasteurized products in accelerated storage conditions were also studied. The research project was separated into two phases. …

The Desubjectified Subject In The Poetry Of Rosmarie Waldrop, Amanda Rebecca Johnson

All Theses

Criticism of Rosmarie Waldrop’s Driven to Abstraction has centered around her fascination with the notion of zero as both a negation and the locus of infinity, but has so far neglected to discuss the implications that this lacuna has on the role of the subject. True to its title, Driven takes the reader on a journey toward nothingness where desubjectification is made into the subject of the work. Through the use of the prose poem which eschews traditional poetic form and conventional syntax, Waldrop employs a collage that not only provides material representation of abstract concepts, but also demonstrates the …