Digital Commons Network^™

Pattern Recognition For Electric Power System Protection, Yong Sheng

Doctoral Dissertations

The objective of this research is to demonstrate pattern recognition tools such as decision trees (DTs) and neural networks that will improve and automate the design of relay protection functions in electric power systems. Protection functions that will benefit from the research include relay algorithms for high voltage transformer protection (TP) and for high impedance fault (HIF) detection. A methodology, which uses DTs and wavelet analysis to distinguish transformer internal faults from other conditions that are easily mistaken for internal faults, has been developed. Also, a DT based solution is proposed to discriminate HIFs from normal operations that may confuse …

Comparison Of The Transformational Leadership Practices Of Principals Of Charter Schools And Principals Of Traditional Public Schools In Louisiana, Charles W. Patterson

Doctoral Dissertations

The primary purpose of this study was to compare the transformational leadership practices of principals of charter schools and traditional public schools in Louisiana. A causal-comparative research design was utilized. All charter schools were asked to participate in the study, and a matched sample of public schools was selected for the comparison group.

Key findings suggest that charter school and traditional public school principals possess transformational leadership skills. However, there was no difference between the groups in the extent to which they practiced these behaviors. Teachers' perceptions did not differ from principals' self-reported practices. Personal and professional characteristics did not …

A Study Of The Implementation Of The National Geography Standards And Their Alignment With Classroom Instruction In United States Pk–12 Schools, S. Kay Gandy

Doctoral Dissertations

In the 1980s, media reports of the state of geography in United States schools and national assessments documenting the failing grades of American students resulted in a campaign to eradicate geographic illiteracy. As a result, there have been many reforms made in geography education, including the development of national geography standards. The National Geographic Society developed a Geography Education Foundation to introduce a grassroots movement for curricula change through teacher inservice institutes. Furthermore, geography was recognized as a core subject in the curriculum designated by President George Bush and the governors of the United States of America as part of …

Modular Machine Learning Methods For Computer-Aided Diagnosis Of Breast Cancer, Mia Kathleen Markey '94

Doctoral Dissertations

The purpose of this study was to improve breast cancer diagnosis by reducing the number of benign biopsies performed. To this end, we investigated modular and ensemble systems of machine learning methods for computer-aided diagnosis (CAD) of breast cancer. A modular system partitions the input space into smaller domains, each of which is handled by a local model. An ensemble system uses multiple models for the same cases and combines the models' predictions.

Five supervised machine learning techniques (LDA, SVM, BP-ANN, CBR, CART) were trained to predict the biopsy outcome from mammographic findings (BIRADS™) and patient age based on a …

Efficiency And Performance Of Real Estate Investment Trusts (Reits): An Empirical Examination, Can Topuz

Doctoral Dissertations

This study has a threefold purpose. Its first objective is to investigate input and output efficiencies in the Real Estate Investment Trust (REIT) industry. Its second objective is to understand the impact of size, property share, loan production, debt ratio, property and geographic diversification, control and governance variables, overall risk, capital risk, growth rate, and management type on a number of efficiency measures, including profit, cost, allocative, technical, pure technical and scale efficiency. The third objective is to assess the impact of structural and regulatory changes in the industry on REITs' productivity, technology, and efficiency changes.

I have estimated the …

Fuzzy Product -Limit Estimators: Soft Computing In The Presence Of Very Small And Highly Censored Data Sets, Kian Lawrence Pokorny

Doctoral Dissertations

When very few data are available and a high proportion of the data is censored, accurate estimates of reliability are problematic. Standard statistical methods require a more complete data set, and with any fewer data, expert knowledge or heuristic methods are required. In the current research a computational system is developed that obtains a survival curve, point estimate, and confidence interval about the point estimate.

The system uses numerical methods to define fuzzy membership functions about each data point that quantify uncertainty due to censoring. The “fuzzy” data are then used to estimate a survival curve, and the mean survival …

Modeling And Experimental Verification Of Growth Of An Axisymmetric Cylindrical Rod By Three-Dimensional Laser-Induced Chemical Vapor Deposition, Qing Chen

Doctoral Dissertations

Three-dimensional laser-induced chemical vapor deposition (3D-LCVD) is a recently developed micro-manufacturing process that holds great potential for the production of complex microstructures with high aspect ratio. A laser beam is focused through a vacuum chamber window onto a movable substrate. The heat from the laser at or near the focal spot on the substrate induces the decomposition reaction of precursor gas in the chamber. As a result, solid-phase reaction products are deposited on the substrate to form the microstructure. In this dissertation, a numerical model is developed for simulating kinetically-limited growth of an axisymmetric cylindrical rod by pre-specifying the surface …

Asp -Pricing: A Black -Scholes Option Pricing Formulation, Chaitanya Singh

Doctoral Dissertations

The Applications Service Provider (ASP) arrangement has engendered a revolution in the area of corporate information technology (IT) by transforming software from a packaged off-the-shelf product to an on-line virtual service.

The focus of this study is to establish a sound mathematical foundation for evaluating software rental agreements (embedding exit flexibility) by incorporating a real options framework (based upon the Black-Scholes approach) into the traditional capital budgeting technique. The static discounted cash flow or net present value analysis may not adequately serve as a ‘barometer’ of outsourcing value due to its inherent weaknesses. On the other hand, the options approach …

A New Long -Term Design Model For Rehabilitation Pipe Liners, Shanyun Wang

Doctoral Dissertations

Thin-walled plastic pipe liners are routinely used to rehabilitate structurally sound host pipes that have lost their hydraulic integrity. Such liners are often installed below the water table and are consequently subjected to external hydrostatic pressure which may lead to creep-induced radial deflections and eventual collapse of the liner within the host pipe. Most of the current liner design model is based on the extension of short-term model to a long-term buckling liner design method. The objective of this thesis is to examine and provide a correction factor C* to allow short-term liner buckling models to be more accurately used …

Identifying Gifted African-American Students: A Case Study Of A Louisiana School System, Donna Lynn Sutton

Doctoral Dissertations

In 1995, the Office for Civil Rights conducted a compliance review of the Bayou Parish School System (a pseudonym) in Louisiana. The review revealed a statistically significant underrepresentation of African-American students in the Bayou Parish gifted program. This case study examined how African-American representation in a gifted program may be increased through the use of research-based interventions implemented by the Office for Civil Rights.

The researcher used both quantitative and qualitative methods to collect and analyze data. Documents from the Office for Civil Rights and the Louisiana Department of Education were examined to: (a) show patterns of African-American and nonminority …

Testing For The Significance Of Induced Highway Travel Demand In Metropolitan Areas, Lawrence Craig Barr

Doctoral Dissertations

The theory of induced growth in vehicle travel hypothesizes that highway improvements which add capacity to a specific corridor or regional transportation network will attract increased levels of vehicle traffic. This relationship of highway capacity to travel demand is an important consideration when evaluating how effective highway expansion alternatives will be in solving transportation problems. Two different but complementary empirical studies were conducted to quantify the effect of highway system improvements on travel behavior. In the first study, I apply ordinary least squares regression models to estimate travel demand elasticities with respect to travel time using travel survey data from …

Human -Machine System Design Optimization For Nondeterministic Spacecraft Anomaly Determination/Resolution, Kriss Quinn Hunold

Doctoral Dissertations

This research examines the dependence of knowledge on decision making with varying levels of uncertainty or non-deterministic situations. The work presented outlines a global approach that is not limited to a specific case study example, but can also be translated to other systems requiring operators, a degree of automation, time constraints, remote control, and high levels of personnel expertise. The specific objective of this study was to address the uncertainty inherent in satellite command and control and to assess and understand the role of human knowledge in the combined human-machine system unit. This research focused solely on the user component …

Physical And Chemical Characterization Of Single Atmospheric Aerosols: Laboratory Studies Of Interactions Of Acidic Trace Gases With Sea -Salt Aerosols, And, Development Efforts For An Aerosol Charging System Using A Corona Discharge, Matthew Brigham Loomis

Doctoral Dissertations

There has long been an interest for in situ analysis of single atmospheric aerosols. To this end, the Flytrap instrument was developed under a NASA Phase I and Phase II Small Business Innovative Research Grant. The centerpiece of the instrument was a spherical void electrodynamic levitator that was used to suspend and optically characterize the physical and chemical properties of individual aerosols. Physical measurements of the aerosols were conducted with the aid of a Mie scattering system while chemical characterization was conducted with a Raman spectroscopy microprobe. A large effort focused on development of a system for charging and trapping …

Application Of Characteristic Mode Analysis To Variable Antenna Placement On Devices Operating In The Near -Resonant Range, David Anthony Strohschein

Doctoral Dissertations

As antenna sizes on portable wireless devices decrease to the dimensions of the device itself and to that of the operating wavelength, the system begins to operate in the near-resonant frequency range. Currently, a straightforward synthesis approach for determining optimal antenna placement within such near-resonant range systems does not exist. Previously, characteristic mode analysis had only been applied to systems with constant geometry that operated in the near-resonant range and the system had constant characteristic modes independent of the probe location. Successful application of characteristic mode analysis to radiating systems with a constant characteristic mode response suggest that a similar …

The Manifestation Of Leadership In Three High -Flying New Hampshire Elementary Schools, Steven Thomas Kelley

Doctoral Dissertations

Perhaps the most dominant feature marking today's educational landscape is the presence and growth of "reform efforts" occurring in schools everywhere. Educational institutions across the U.S. struggle to reform and improve the teaching and learning that occurs within their walls. The public demands higher standards, has greater expectations, and demands academic excellence. State testing has pointed out strengths and weaknesses present in our schools and in some cases, prompted state governments to intervene in an attempt to "rescue" schools that are not demonstrating adequate progress.

Over the past fifty years, school administrators and educational researchers have been captivated by the …

Mode Conversion And Wave -Particle Interaction Processes In The Solar Wind, Edisher Kh Kaghashvili

Doctoral Dissertations

This thesis presents the theoretical study of wave coupling and wave-particle interaction processes in the solar corona and wind. We first investigate the effect of an inhomogeneous velocity field on the propagation of waves in the solar atmosphere. We find that coupling between Alfven waves and fast magnetosonic waves can occur for parameters characterizing the coronal holes. For streamer conditions, the Alfven wave couples to the slow magnetosonic mode. In the inner corona, it seems that these two possible ways of coupling do not occur simultaneously in the same structures, while beyond 5--10 R⊙ , where the plasma beta is …

Improved Swellable Polymer Microspheres For Chemical Sensing, Necati Kaval

Doctoral Dissertations

Derivatized lightly crosslinked polymer microspheres that swell and shrink as a function of pH have been investigated to develop polymeric transduction elements for fiber optic sensors and other sensors. The microspheres were immobilized in hydrogels forming a membrane. The membranes look turbid because of the difference between the refractive index of hydrogel and the refractive index of microspheres. As the microspheres swell as a function of pH, their refractive index decreases approaching the refractive index of the hydrogel. As a result, the turbidity of the membrane decreases. The change in the turbidity of the membrane was monitored by a UV-Vis-NIR …

Life History Dynamics Of Nudibranch Sibling Species In The Genus Dendronotus In The Gulf Of Maine, Chad Gordon Sisson

Doctoral Dissertations

Two different larval types have been described for the nudibranch Dendronotus frondosus (Ascanius, 1774) in the Gulf of Maine. A taxonomic review of adults with planktrophic larvae and those with lecithotrophic larvae revealed regular differences in radula morphology, and no predictable differences in the reproductive system. These data and previous data on a behavioral reproductive isolation mechanism suggest a new species designation for populations of Dendronotus with lecithotrophic larvae. Laboratory studies were used to compare the larval dispersal potential of the two types of Dendronotus. D. frondosus planktotrophic larvae had a potential planktonic period of approximately 11 weeks at 10°C …

Oxygen And Nitrate Enhanced In Situ Bioremediation Of An Oil -Contaminated Salt Marsh, Fabio A. Roldan-Garcia

Doctoral Dissertations

Salt marshes are among the most ecologically-sensitive areas to oil spills and remediation activities. Contaminated marshes may take years or decades to recover. Bioremediation is the process of enhancing naturally-occurring biodegradation by supplying limiting nutrients and terminal electron acceptors (TEAS). During this study, two TEAS (O2 and NO3 -) were evaluated for their ability to enhance natural in situ biodegradation of total petroleum hydrocarbons (TPH) in an oil-contaminated marsh. EPA (9071A) and ASTM (D5831) methods were evaluated for screening TPH in the contaminated marsh sediments. The ASTM Method was selected to evaluate TPH levels in candidate sites at the Fore …

Host Finding And Recognition By Papilio Polyxenes (Lepidoptera: Papilionidae): The Effects Of Three Host Cues And Of Host-Plant Experience On Oviposition Behavior, Cheryl Ann Heinz '89

Doctoral Dissertations

Herbivorous insects are rarely able to eat all kinds of available plant material. The majority of phytophagous insects are oligophagous, feeding on a variety of host plants that are botanically and/or chemically related (Strong, et al. 1984; Jermy, et al. 1990; Bemays and Chapman 1994). This provides these insects the flexibility to exploit a variety of plant species; however, even closely-related plants can differ in such phenotypic characters as growth form, leaf shape, and chemistry. How then can we account for the fidelity of oligophagous insects for a particular set of plants growing in complex vegetation? Clearly, host-finding responses to …

A Test Of The Ideal Free Distribution In Panhandling Humans, Leann Louise Milinder

Doctoral Dissertations

The Ideal Free Distribution (Fretwell and Lucas, 1970), an optimization model from behavioral ecology, predicts that a group of animals will distribute themselves across habitats with unequal resources such that all animals have equal success rates. The six experiments of this dissertation demonstrated that humans conform to the IFD with about the same sensitivity as animals and respond similarly when assumptions of the model are violated. The present study also revealed that cooperation, and its effect on the functional size of the foraging unit, may be an important factor in understanding the distribution of social foragers.

Experiments 1 and 2 …

A Comparative Study Of Just-In-Time (Jit) And Theory Of Constraints (Toc) Systems With Varying Constraint Locations And Operational Characteristics, Pirun Hemmondharop

Doctoral Dissertations

"Various researchers have extolled the benefits of Theory of Constraints (TOC), Just-in-Time (JIT), and other manufacturing strategies. Some supporters of JIT argue it is the least costly, while others point to the overall benefits of TOC. There are conflicting claims as to the best manufacturing philosophies which is compounded by the fact that no one system is best in every situation. The success of a production system truly depends on the manufacturing environment rather than the philosophy being used. This study uses computer simulations of differing manufacturing environments to compare Just-in-Time (JIT) and Theory of Constraints (TOC) philosophies over two …

Automated Myocardial Infarction Diagnosis From Ecg, Chen Zhou

Doctoral Dissertations

In the present dissertation, an automated neural network-based ECG diagnosing system was designed to detect the presence of myocardial infarction based on the hypothesis that an artificial neural network-based ECG interpretation system may improve the clinical myocardial infarction. 137 patients were included. Among them 122 had myocardial infarction, but the remaining 15 were normal. The sensitivity and the specificity of present system were 92.2% and 50.7% respectively. The sensitivity was consistent with relevant research. The relatively low specificity results from the rippling of the low pass filtering. We can conclude that neural network-based system is a promising aid for the …

Role Of Nitric Oxide As A Modulator Of Platelet Dense Granule Release, Clifton Ford Frilot Ii

Doctoral Dissertations

Nitric oxide (NO) has been shown to suppress platelet activation, induce vasodilation, inhibit smooth muscle cell proliferation, and act against infection. Activated platelets generally have opposite effects from these. They secrete platelet-derived growth factor (PDGF), which stimulates smooth muscle growth, serotonin, which is a platelet agonist, and a number of agents that promote further platelet aggregation. However, activated platelets also produce NO through the enzymatic functions of the constitutive form of nitric oxide synthase (NOS). The primary functions of this capability are not yet completely understood. Due to its low molecular weight and high diffusivity, NO is quickly transported from …

Perceptions Of Principals As To The Degree Of Implementation And Effect Of The Middle School Concept In Louisiana, Susan Nelson Shofner

Doctoral Dissertations

Turning Points: Preparing American Youth for the 21st Century (Carnegie, 1989) contained recommendations for improving middle level education. These recommendations included: (a) creating small communities for learning, (b) teaching a common knowledge core, (c) ensuring success for all students, (d) empowering teachers and administrators, (e) preparing teachers in middle grades, (f) improving academic performance through health and fitness, (g) re-engaging families in the education of adolescents, and (h) connecting schools with communities.

The objectives of this study were to determine, according to middle school principals, the extent to which the Carnegie recommendations have been implemented in the public schools of …

Statistical Modeling And Inference Regarding Risk In Case Control Studies, Deborah Kay Shepherd

Doctoral Dissertations

Some of the common measures of risk used m epidemiology today are the relative risk, the odds ratio, the attributable risk, and the chi-square goodness of fit test. All of these measures have their shortcomings. A new approach to measuring risk in case-control studies is to use the unitless measure of the coefficient of variation of incidence of disease over the risk categories, kˆ2, first proposed by Begg et al. (1998). Begg et al. (1998), also showed that the product of multiple risk factors may be compared to an overall measure of the square of the coefficient of variation …

Generation Of Oxygen Microbubbles In A Microchannel With Crosscurrent Liquid Flow, Sung Sam Kim

Doctoral Dissertations

An alternative way of blood oxygenation is proposed by introducing small bubbles directly into the blood stream. To be used for blood oxygenation, the bubble should be small enough to pass through the capillary beds. To explore the feasibility of producing small bubbles, bubble formation phenomena in a crosscurrent liquid flow in a silicon microchannel were studied. Small orifices with 4 μm, 4.2 μm, and 6.6 μm hydraulic diameter were machined in a direction perpendicular to a trapezoidal channel that has a hydraulic diameter of 42 micrometers. These orifices were connected to three different chambers of 2.5 × 10−7 cm3, …

Fundamental Approach To Exchange Rate Modeling: Toward An Augmented Theory Of Purchasing Power Parity, Jianzhou Zhu

Doctoral Dissertations

In this dissertation, I test the homogeneity and symmetry conditions of PPP by applying the Johansen multivariate cointegration methodology to quarterly data for six countries. I perform the tests in the framework of both a traditional version and an augmented version of PPP. The results of tests on the traditional version of PPP reveal that in all cases the theoretical PPP-vector [1, 1, −1] is not contained in the cointegrating space. This finding is consistent with that of existing literature and indicates the empirical failure of the homogeneity and symmetry conditions of PPP. However, when the traditional PPP is augmented …

Statistical Properties Of Maximum Likelihood Estimates For Accelerated Lifetime Data Under The Weibull Model, Mahmoud A. Yousef

Doctoral Dissertations

Pipe rehabilitation liners are often installed in host pipes that lie below the water table. As such, they are subjected to external hydrostatic pressure. The external pressure leads to early deformation in the liners, which could ultimately lead to its failing or buckling before its expected service lifetime is achieved. Experiments involving long term buckling behavior of liners are typically accelerated lifetime testing procedures. In an accelerated testing procedure a liner is subjected to a constant external hydrostatic pressure and observed until it fails or for a certain time, t whichever occurs first. Liners that do not fail at time …

A Multigrid Method For Elliptic Grid Generation Using Compact Schemes, Balaji S. Iyangar

Doctoral Dissertations

Traditional iterative methods are stalling numerical processes, in which the error has relatively small changes from one iteration to the next. Multigrid methods overcome the limitations of iterative methods and are computationally efficient. Convergence of iterative methods for elliptic partial differential equations is extremely slow. In particular, the convergence of the non-linear elliptic Poisson grid generation equations used for elliptic grid generation is very slow. Multigrid methods are fast converging methods when applied to elliptic partial differential equations. In this dissertation, a non-linear multigrid algorithm is used to accelerate the convergence of the non-linear elliptic Poisson grid generation method. The …