Digital Commons Network^™

Using Character Varieties: Presentations, Invariants, Divisibility And Determinants, Jeffrey Allan Hall

Doctoral Dissertations

If G is a finitely generated group, then the set of all characters from G into a linear algebraic group is a useful (but not complete) invariant of G . In this thesis, we present some new methods for computing with the variety of SL2C -characters of a finitely presented group. We review the theory of Fricke characters, and introduce a notion of presentation simplicity which uses these results. With this definition, we give a set of GAP routines which facilitate the simplification of group presentations. We provide an explicit canonical basis for an invariant ring associated with a symmetrically …

Displacement-Based Analysis And Design Of Rigid Retaining Walls During Earthquakes, Yingwei Wu

Doctoral Dissertations

"This research focused on the analysis and design of rigid retaining walls subjected to earthquakes and considered nonlinear foundation soil properties. The simultaneous sliding and rocking movements of retaining walls were considered. Seven field conditions, including moist, submerged, perched and saturated backfill with a sloping drain, were specified by design codes. A computer program capable of computing displacement using real time history records or equivalent sinusoidal motions was developed. Finally, a dynamic design procedure was proposed for practicing engineers.

The study revealed that maximum shear modulus in foundation soil, maximum ground acceleration, and soil nonlinearity had significant effect on the …

Machine Tool Accuracy Characterization, Error Modeling And Compensation Using Telescopic Ballbar And Laser Interferometer, Yalcin M. Ertekin

Doctoral Dissertations

"This dissertation presents the results of the research investigation on the machine tool accuracy characterization, error modeling and error compensation using telescopic ballbar and laser interferometer. Increasing demand for both higher machine tool accuracy and machining tolerances has resulted in a great need to measure and characterize the accuracy of NC machine tools and minimize machine tool induced errors on machined components before manufacturing parts, instead of inferring it from parts already machined. Using a telescopic magnetic ballbar, the results of the accuracy assessment of an old Bridgeport Series I CNC 2 1/2 axes vertical machining center are presented in …

Stability Of Paleosinks And Karstic Carbonates In The Southern Fire Clay Mining District Of Missouri, Robert Weiser Dillon

Doctoral Dissertations

"The Southern Fire Clay District of Missouri was intensely mined during the late-1800’s to mid-1900’s for its valuable resource of high refractory clays deposited within Pennsylvanian sinkholes “paleosinks”. Mining operations have produced modifications in the Ozark aquifer, which in effect has possibly increased the instability of this paleokarst terrain and the potential of further environmental impacts to the land. Evidence supporting this hypothesis are: (1) A southerly shift in the regional groundwater divide relative to the topographic divide. This possibly is caused by the distribution of leaking clay pits, which suggests that the bedrock permeability or hydraulic conductivity has been …

Determinants Of Loan Losses In National Banks: Size, Regulation, And The Aicpa Model, Randy Marl Reed

Doctoral Dissertations

Because of recent failures, the AICPA Banking Committee has developed a normative model citing specific variables for auditors to use in bank audits. This research has examined that AICPA model.

In addition, the Auditing Principles Board has identified several areas of concern for auditing internal control structures. Research into size and regulation from other sources has indicated that both are significant modifiers of financial models. Regulations now require banks and holding companies of more than $500 million in assets to submit to an annual independent audit.

The primary purpose of this research was to determine whether the AICPA normative model …

Fuzzy Logic Applied To System Control To Enhance Commercial Appliance Performance, Glenn Moffett

Doctoral Dissertations

The purpose of this research is to determine the usefulness of fuzzy logic and fuzzy control when applied to a commercial appliance. Fuzzy logic is a structured, model-free estimator that approximates a function through linguistic input/output associations. Fuzzy rule-based systems apply these methods to solve many types of "real-world" problems, especially where a system is difficult to model, is controlled by a human operator or expert, or where ambiguity or vagueness is common.

This dissertation presents fuzzy sets, fuzzy systems, and fuzzy control, with an example conveying the use of fuzzy control of a consumer product and an overview of …

A Quantitative Analysis Of The Effects Of Chess Instruction On The Mathematics Achievement Of Southern, Rural, Black Secondary Students, James Paul Smith

Doctoral Dissertations

This study investigates the effects of chess instruction on the mathematics achievement of a group of southern, rural, black, secondary students. Instruments used included the mathematics section of the CAT (Level 20), Group Embedded Figures Test (GEFT), Matrix Analogies Test-Short Form (MAT-SF), Guilford-Zimmerman Spatial Visualization Test (SV), and Guilford Zimmerman Spatial Orientation Test (SO). The treatment group, which received 18 weeks of chess instruction, consisted of 11 females and 8 males. The control group was comprised of 10 females and 10 males. All participants were high school juniors or seniors. Analysis of variance of the pre-tests found no significant differences …

A Study Of Calculator Usage On The Mathematics Achievement Of Seventh- And Eighth-Grade Students And On Attitudes Of Students And Teachers, Tracie Bidwell Ellerman

Doctoral Dissertations

The purpose of this study was to examine the effects of calculator usage on the mathematics achievement of seventh and eighth grade students as measured by the Mathematics Concepts and Applications sections of the California Achievement Test. The study also investigated the attitudes of students and teachers toward calculator usage. Student attitudes were measured through responses to the Student Calculator Survey. Teacher attitudes were measured through responses to the Attitude Instrument for Mathematics and Applied Technology-Version II.

Intact classes from two north central Louisiana school systems were assigned randomly to treatment and control groups. The sample consisted of 1070 students …

The Effect Of Pipe Bursting On Nearby Utilities, Pavement, And Structures, Alan Atalah

Doctoral Dissertations

This dissertation has involved field and analytical studies of ground movements, ground vibrations and other design issues associated with trenchless pipe replacement (or pipe bursting, as it is commonly known). The process is used to replace an existing underground service pipe with a completely new pipe but without the disturbance and cost of excavating a trench from the surface. The process typically involves the insertion of a tool into the existing pipe that has a maximum diameter that is slightly larger than the existing pipe. This tool is used to break the existing pipe into pieces and to displace the …

Literacies Without Judgment: Composing A (Con)Text For Cultural Healing In Northeast Brazil, Francisco Silva Cavalcante Jr.

Doctoral Dissertations

In this study the researcher describes and interprets the experiences with Projeto (Con)texto, a research group created in Northeast Brazil composed of eleven people with different levels of formal schooling, social classes and ages varying from 14 to 50 years old. The researcher explores the dynamics of the Brazilian relational universe and its impact on people's lives, the multiple forms of letramento (literacies) used by people in a certain cultural context to construe and convey meaning, and the process of strengthening of one's self to deal with cultural conflicts through cultural healing.

The researcher gathered descriptive data during one year …

Transactional Bond In The Novels Of Charles Brockden Brown, Gretchen Elspeth Digeronimo

Doctoral Dissertations

The six novels and various other fiction pieces Charles Brockden Brown wrote between 1799 and 1801 coherently demonstrate the operation and effect of literary and artistic representation in early Republican America.

In original close readings of Arthur Mervyn, Edgar Huntly, Ormond, and several other works, this dissertation identifies transactional bond and describes how Brown charted the establishment of the public and private individual self through transactional bond in three specific arenas: relationships between the developing self and written, visual, or reported representation; relationships between master/mentors and apprentices; relationships among women.

Bonds that begin, operate, and dissolve between male characters are …

Fluid-Structure Interaction In Taylor-Couette Flow, Martin Horst Willi Kempf

Doctoral Dissertations

The linear stability of a viscous fluid between two concentric, rotating cylinders is considered. The inner cylinder is a rigid boundary and the outer cylinder has an elastic layer exposed to the fluid. The subject is motivated by flow between two adjoining rollers in a printing press. The governing equations of the fluid layer are the incompressible Navier-Stokes equations, and the governing equations of the elastic layer are Navier's equations. A narrow gap, neutral stability, and axisymmetric disturbances are assumed. The solution involves a novel technique for treating two layer stability problems, where an exact solution in the elastic layer …

Alternative Removal Methodologies For Environmental Waters, Shannon Patrick Hogan

Doctoral Dissertations

The Environmental Protection Agency (EPA) continues to establish criteria for the reduction of pathogens in environmental waters used for drinking water. The EPA also states criteria on the amount of chlorine by-products allowed in drinking water. Alternative removal methods that are used in conjunction with chlorine are needed to assure safe drinking water.

The Surface Water Treatment Rule (SWTR) states that a 99.99% reduction of viruses and a 99.9% reduction in Giardia lamblia cysts needs to be achieved by a treatment facility that uses surface water for the production of drinking water. The SWTR also states Maximum Contaminant Levels (MCL) …

Music And The General Classroom: Literacy In A New Key, F Dan Seger

Doctoral Dissertations

After a personal description of the traditional role of music education and its relationship to the overall curriculum of an American elementary school, this dissertation asks: What do grade 4/5 students do when their classroom and music teachers integrate music more deliberately into classroom life? Set in a classroom in a small New England town, the dissertation describes how a collaboration between a classroom teacher and a music teacher brought the music curriculum into the daily lives of students in a school where scheduled music class occurred only once per week.

Viewing music as a valid means to represent thought …

Factors That Influence The Decision Regarding Hormone Replacement Therapy In Postmenopausal Women, Ruth A Rogers Reilly

Doctoral Dissertations

Cardiovascular disease is the leading cause of death in women in the United States today. Prior to menopause women have lower rates of heart disease than men; however, after menopause a woman's risk for heart disease rises dramatically. This is thought to be due the ovaries' decreased production of estradiol, but the mechanisms for this effect have not been fully elucidated. The need exists to investigate the impact of healthy lifestyles on attenuating the risk of cardiovascular disease in women as they age.

The majority of research on hormone replacement therapy (HRT) has focused on the biomedical model suggesting that …

Ice Core Glaciochemical Records Of Late Holocene Climatic Variability In West Antarctica, Karl Jacob Kreutz

Doctoral Dissertations

The complex atmospheric and glaciological dynamics of West Antarctica make this region of particular interest in addressing the continent's cause and effect relationship in the global climate system, and for evaluating future global change scenarios. Ice core records from this region provide the resolution necessary to both improve our understanding of modern regional climate variability, and to reconstruct past changes in a number of climate components.

High-resolution (subannual to biannual) snow and ice core samples collected from two regions of West Antarctica, Siple Dome and Marie Byrd Land, were analyzed for water soluble major ion content. Examination of detailed surface …

Examining Student Conceptions Of The Nature Of Science From Two Project-Based Classrooms, David M. Moss

Doctoral Dissertations

The purpose of this research was to develop descriptive accounts of precollege students' conceptions of the nature of science from two project-based classrooms, and track those conceptions over the course of an academic year. A model of the nature of science was developed and served as the criterion by which students' beliefs were evaluated. The model distinguishes between two major categories of science, the nature of the scientific enterprise and the nature of scientific knowledge. Five students were selected from each class and interviewed individually for 30-45 minutes each, six times over the year. Data from semi-structured, formal interviewing consisted …

Differentiation And Composition On The Hardy And Bergman Spaces, Neil Portnoy

Doctoral Dissertations

Banach spaces of analytic functions are defined by norming a collection of these functions defined on a set X. Among the most studied are the Hardy and Bergman spaces of analytic functions on the unit disc in the complex plane. This is likely due to the richness of these spaces.

An analytic self-map of the unit disc induces a composition operator on these spaces in the natural way. Beginning with independent papers by E. Nordgren and J. V. Ryff in the 1960's, much work has been done to relate the properties of the composition operator to the characteristics of the …

The Role Of Industrial Innovation In Growth And Convergence Across The United States States, Norman Henry Sedgley Iii.

Doctoral Dissertations

This dissertation is concerned with testing economic growth theory using data from US States. Work on endogenous growth has recently been extended to determine the rate of technological change across economies where the incentive to innovate is linked to economic rewards. These models of endogenous innovation are on the cutting edge of theoretical advances in economic growth.

I extend the endogenous innovation literature to study the consequences of knowledge spillovers and the different industrial concentrations that clearly exist across states. This extension of the theory suggests it is reasonable to expect rates of innovation to differ across states if knowledge …

A Very High Level Logic Synthesis, Norbert Ange Valverde

Doctoral Dissertations

The evolution of Computer Aided Design (CAD) calls for the incorporation of design specifications into a microelectronics system development cycle. This expansion requires the establishment of a new generation of CAD procedures, defined as Very High Level Logic Synthesis (VHLLS). The fundamental characteristics of open-ended VHLLS are: (1) front-end graphical interface; (2) time encapsulation; and (3) automatic translation into a behavioral description. Consequently, the VHLLS paradigm represents an advanced category of CAD-based microelectronics system design, built on a deep usage of expert systems and intelligent methods. Artificial Intelligence (AI) formalisms such as Knowledge Representation System (KRS) are necessary to model …

Fixation And Incubation Effects In Problem-Solving, Marie Theresa Hansberry

Doctoral Dissertations

In four experiments, the effects of fixation and suppression processes in problem solving ability were investigated. Previous research has shown that efficient suppression mechanisms are integral to verbal ability (e.g., Gernsbacher & Faust, 1991; Gernsbacher, Varner, & Faust, 1990; Hartman & Hasher, 1991). The present set of experiments demonstrated that such a mechanism is also a component of problem solving ability. The efficiency with which participants were able to suppress inappropriate meanings of ambiguous words was used as a measure of suppression skill. Experiment I established that participants who were able to make use of previously-presented information to solve difficult …

Money, Output And Real Wages In A New Keynesian Framework With Heterogeneous Labor And Monopsonistic Firms, Robert J. Martel

Doctoral Dissertations

Representative agent models do not match up well with three stylized facts of the business cycle: a money-output connection, countercyclical markups, and acyclical real wages. This thesis investigates whether a New Keynesian model which departs from the representative agent assumptions and models heterogeneity and imperfect competition in the labor market is more consistent with these stylized facts.

One possible explanation of countercyclical markups and acyclical real wages is that labor markets are monopsonistic and monopsony power is weaker during expansions than in recessions, This would require that the elasticity of labor supply be procyclical. This is not possible if worker …

Stability And Weight Smoothing In Cmac Neural Networks, David Paul Campagna

Doctoral Dissertations

Although the CMAC (Cerebellar Model Articulation Controller) neural network has been successfully used in control systems for many years, its property of local generalization, the availability of trained information for network responses at adjacent untrained locations, although responsible for the networks rapid learning and efficient implementation, results in network responses that is, when trained with sparse or widely spaced training data, spiky in nature even when the underlying function being learned is quite smooth. Since the derivative of such a network response can vary widely, the CMAC's usefulness for solving optimization problems as well as for certain other control system …

The Impact Of The Louisiana Lottery On Salaries In Education, Melissa Vicknair Melancon

Doctoral Dissertations

The study was undertaken to decide whether lottery revenues impacted teachers' salaries in Louisiana. Economic recession brought on by the collapse of the oil and gas industry, disgruntled taxpayers, and the lure of easy money prompted Louisiana legislators to pass a bill adopting a state lottery. Initially, all funds were earmarked for education. Subsequently, lottery revenues were deposited into the general fund. Yet many thought the lottery would be a significant source of money for education and teachers' salaries.

Logged annual salaries were used in models for university teachers and for elementary and secondary school teachers. Variables were incorporated to …

Portfolio Performance Evaluation Of Institutional Investors: An Empirical Investigation Of Selection Ability Via The Levels Of Institutional Ownership, Risks, Firm Size, And R&D Expenditures, Jawook Baek

Doctoral Dissertations

The purpose of this study is threefold: (1) To evaluate how the portfolio performance of institutional investors differs from the market index portfolio, first, as a whole, and second, as several different institutional ownership portfolios. (2) To investigate the relationship between the institutions' superior stock selection ability and firm quality attributes such as beta, volatility, firm size, and R&D expenditures. Most previous academic work has focused on institutional investment behaviors, finding the relationship between institutional ownership and firm quality attributes, based on only mutual funds. (3) To develop a decision model for future institutional investors' portfolio performance based on the …

Myoglobin-Facilitated Oxygen Diffusion In The Heart: A Mathematical Assessment, Jason D. Gardner

Doctoral Dissertations

Myoglobin facilitated oxygen diffusion and Michaelis-Menten kinetics are added to an experimentally-validated cardiac tissue model to determine the steady-state function of myoglobin in working heart tissue. Previous modeling of tissue oxygen partial pressure (pO$\sb2)$ data suggests that the oxygen diffusion coefficient in working heart tissue is greater than expected. To fit the pO$\sb2$ data, the tissue oxygen diffusion coefficient in the model must be elevated to 8 to 12 times reported values. These elevated values of the tissue oxygen diffusion coefficient are not acceptable based upon the current understanding of cardiac muscle physiology. In this dissertation the effect of including …

Two-Phase Flow In Microchannels, Roger Scott Stanley

Doctoral Dissertations

The purpose of this study was to investigate fluid mechanic and heat transfer characteristics of two-phase two-component flow in rectangular microchannels. Experiments were conducted using rectangular aluminum channels with hydraulic diameters ranging between 56 $\mu$m and 256 $\mu$m and aspect ratios which varied from 0.5 to 1.5. Both single- and two-phase tests were conducted using water and gaseous argon, helium, and nitrogen as the working fluids. The Reynolds number for both types of experiments ranged from approximately 50 to nearly 10,000. The Nusselt number ranged between 0.0002 and 70. The single- and two-phase experimental data were empirically correlated, using parameters …

Judging Contingencies Accurately: The Effects Of Feedback, Practice, And Self-Efficacy, Steven C. Clark

Doctoral Dissertations

Some psychologists have claimed that people are not good at judging covariation (e.g., Smedslund, 1963; Jenkins & Ward, 1965). This claim, however, has been based on the results of experiments that may not have been optimal for promoting judgmental accuracy (Allan & Jenkins, 1980). Other psychologists have claimed that people are relatively good judges of covariation (e.g., Wasserman, Chatlosh, & Neunaber, 1983; Wasserman & Shaklee, 1984). Common to most of this research is an experimental paradigm in which participants do not ever receive feedback concerning the accuracy of their judgments.

The two experiments in this dissertation were designed to promote …

Dynamic Response Of Poroelastic Materials Containing Bingham Fluid: Application To Electrorheological Fluids, Mete Kesan

Doctoral Dissertations

This work examines the dynamic response to harmonic loading of a disk of poroelastic material containing non-Newtonian Bingham fluid which exhibits a yield stress. Biot's poroelasticity equations and modified Darcy's law for non-Newtonian fluids exhibiting a yield stress are combined together to obtain the governing equations of the system for quasi-static case. Dissipation due to friction arising from the flow of fluid relative to the solid is taken into account but inertia effects are neglected. The response and the complex modulus of the system are calculated using the finite element method taking into account the nonlinear nature of Bingham fluid. …

Student Achievement, Parental Effort And Schooling, Andrew James Houtenville

Doctoral Dissertations

When evaluating public education programs that are aimed at improving student achievement, it is often assumed that a child's family background is an exogenous factor, albeit an important factor. However, parental decisions may be influenced by such programs. It is the assertion of Becker and Tomes (1976) that distortions in parental behavior (time allocation) may be one of the reasons that compensatory education fails to improve student achievement. In short, parents reduce their own effort when school services (schooling) is increased. However, theoretically parental responses are ambiguous; parental effort can increase or decrease in response to increased schooling. This dissertation …