Digital Commons Network^™

Computing A Diameter-Constrained Minimum Spanning Tree, Ayman Mahmoud Abdalla

Retrospective Theses and Dissertations

In numerous practical applications, it is necessary to find the smallest possible tree with a bounded diameter. A diameter-constrained minimum spanning tree (DCMST) of a given undirected, edge-weighted graph, G, is the smallest-weight spanning tree of all spanning trees of G which contain no path with more than k edges, where k is a given positive integer. The problem of finding a DCMST is NP-complete for all values of k; 4 ≤ k ≤ (n - 2), except when all edge-weights are identical.

A DCMST is essential for the efficiency of various distributed mutual exclusion algorithms, where …

Low Voltage Regulator Modules And Single Stage Front-End Converters, Wei Gu

Retrospective Theses and Dissertations

Evolution in microprocessor technology poses new challenges for supplying power to these devices. To meet demands for faster and more efficient data processing, modem microprocessors are being designed with lower voltage implementations. More devices will be packed on a single processor chip and the processors will operate at higher frequencies, exceeding 1GHz. New high-performance microprocessors may require from 40 to 80 watts of power for the CPU alone. Load current must be supplied with up to 30A/µs slew rate while keeping the output voltage within tight regulation and response time tolerances. Therefore, special power supplies and Voltage Regulator Modules (VRMs) …

A Framework For The Implementation Of An Iso 9000 Based Certification Program For Printed Circuit Board Manufacturers, Adam Y. Maamoun

Retrospective Theses and Dissertations

ISO 9000:2000 is the newest version of the ISO 9000 family of standards. Unlike the 1994 version, it does not distinguish between servicing, testing and designing standards. It emphasizes quality improvement rather than quality control and briefly explains how to implement the Plan-Do-Check- Act (PDCA) cycle for improvement and the use of statistical techniques to improve the quality of process and product instead of controlling the quality of the output. The thesis explains why companies need to be certified and how to implement quality improvement programs.

The objective of this thesis is to provide generic certification guidelines for printed circuit …

Design And Applications Of Volume Holographic Optical Elements, Steven C. Dunn

Retrospective Theses and Dissertations

Volume gratings were studied both theoretically and experimentally in order to design and analyze practical volume holographic optical elements. The diffraction of finite (Gaussian) beams by transmission gratings is investigated. A closed form solution for the off-Bragg profiles is obtained, and the distortion in the resulting profiles is analyzed. Criteria for when the finiteness of the beam has a minimal effect on the angular selectivity response are given. A model is developed to investigate the cross talk in multiplexed gratings Experimental verification in LiNb0₃ and PTR glass is demonstrated. The diffraction efficiency and output profiles of finite beams diffracted …

Scintillation Behind The Collecting Lens Of A Receiver, Clarissa A. Fleming Russell

Retrospective Theses and Dissertations

One of the negative effects that a laser beam experiences as it propagates through the atmosphere is intensity fluctuations or scintillation. Because scintillation-- as it pertains to laser radar and laser satellite communication systems-- is the main subject of this research, the assumption of an optical element ( such as a Gaussian lens) along the propagation path in front of the detector is valid. The mathematical addition of optical elements to the propagation path is treated using the ABCD ray matrix method. The expression for scintillation is derived, analyzed, and numerically calculated for positions to the left and right of …

Ultrafast Nonlinear Spectrometer For Material Characterization, Raluca A. Negres

Retrospective Theses and Dissertations

This work describes the use of a broadband spectral source for nonlinear spectroscopy to characterize various materials with potential applications in confocal microscopy, biological sample markers, optical limiting devices and optical switches. The goal is to study the spectrum of nonlinear absorption and the dispersion of nonlinear refraction as well as the dynamics of the nonlinearities by means of femtosecond excite-­probe experiments.

The principle is quite simple: if a sample is under the influence of a strong fs excitation pulse and a pro be pulse beam is incident at the same time, or shortly after (within the decay time of …

Use Of Incremental Adaptation And Habituation Regimens For Mitigating Optokinetic Side-Effects, David A. Graeber

Retrospective Theses and Dissertations

The use of incremental and repeated exposures regimens have been put forth as effective means to mitigate visually induced motion sickness based on the Dual Process Theory (DPT) (Groves & Thompson, 1970) of neural plasticity. In essence, DPT suggests that by incrementing stimulus intensity the depression opponent process should be allowed to exert greater control over the net outcome than the sensitization opponent process, thereby minimizing side-effects. This conceptual model was tested by empirically validating the effectiveness of adaptation, incremental adaptation, habituation, and incremental habituation regimens to mitigate side-effects arising from exposure to an optokinetic drum. Forty college students from …

A Comparative Study Of The Feeding Ecology Of Chelonia Mydas (Green Turtle) And The Incidental Ingestion Of Prorocentrum Spp, Karen Gayle Holloway Adkins

Retrospective Theses and Dissertations

The diets of green turtles from five dissimilar aggregations of juvenile C. mydas on the East Coast of Florida were analyzed. C. mydas were captured by tangle net from four of the study sites and a dietary sample was collected by an esophageal flushing technique. The gut content of stranded individuals was collected for the fifth site. The vegetation in these study areas differs in varying degrees of abundance and diversity. Analysis of the samples revealed the alga types preferred by green turtles from each population and provided the basis for examination of similarities and differences in their diets.

Large …

A Unified Approach To Dynamic Modeling Of High Switching Frequency Pwm Converters, Christopher J. Iannello

Retrospective Theses and Dissertations

This dissertation will present the development of a unified approach for dynamic modeling of the PWM and soft-switching power converters. Dynamic modeling of non-linear power converters is very important for the design and stability of their closed loop control. While the use of equivalent circuits is often preferred due to simulation efficiency issues, no unified and widely applicable method for the formulation of these equivalents exists.

A review of conventional modeling technique via the method of state-space averaging will be carried out. Complete development of the averaged, equivalent circuit models for the nonlinear power switch/diode combination in modem power converters …

Efficient Techniques For Management And Delivery Of Video Data, Junghwan Oh

Retrospective Theses and Dissertations

The rapid advances in electronic imaging, storage, data compression telecommunications, and networking technology have resulted in a vast creation and use of digital videos in many important applications such as digital libraries, distance learning, public information systems, electronic commerce, movie on demand, etc. This brings about the need for management as well as delivery of video data. Organizing and managing video data, however, is much more complex than managing conventional text data due to their semantically rich and unstructured contents. Also, the enormous size of video files requires high communication bandwidth for data delivery. In this dissertation, I present the …

View-Centric Reasoning About Parallel And Distributed Computation, Marc L. Smith

Retrospective Theses and Dissertations

The development of distributed applications has not progressed as rapidly as its enabling technologies. In part, this is due to the difficulty of reasoning about such complex systems. In contrast to sequential systems, parallel systems give rise to parallel events, and the resulting uncertainty of the observed order of these events. Loosely coupled distributed systems complicate this even further by introducing the element of multiple imperfect observers of these parallel events. The goal of this dissertation is to advance parallel and distributed systems development by producing a parameterized model that can be instantiated to reflect the computation and coordination properties …

A Hierarchical Channel Selection Scheme For Macro/Micro Cellular Networks, Ayesha Zaheer

Retrospective Theses and Dissertations

Hierarchical channel allocation schemes for cellular networks offer a promising approach to solve the pressing problem of increasing the cellular servicing capacity in spite of the limited radio spectrum available. We propose a hierarchical channel selection scheme for handling handoffs and new calls in micro/macro cellular systems. The scheme is intended to improve the performance and quality of service of these systems by increasing the cell channel utilization, reducing the handoff blocking probability and improving the responsive to new calls.

The proposed scheme is based on several design enhancements including an overflow buffer, which is used for handoff calls that …

The Battle's Lost And Won: Ratification Of The Nineteenth Amendment In Tennessee, Judith Beale

Retrospective Theses and Dissertations

Tennessee ratified the Nineteenth amendment by a margin of one vote. This circumstance has generated myths that serve to obscure rather than enlighten the events that occurred. Historians generally attribute women winning the right to vote to the improvements in their legal status, education, and employment that encouraged women to demand the right to vote. Following suffragists' rhetoric, historians believe that national opposition to women's enfranchisement came from the liquor industry and from railroad industries because they feared that women would vote to maintain prohibition and pass regulating legislation damaging to their industries. Suffragists, therefore, mounted many campaigns that led …

A Multivariate Approach To The Dynamic Of Violence Within Intimate Relationships: An Application Of Theory Of Coercive Power In Exchange, Giovanna Gianesini

Retrospective Theses and Dissertations

This study, drawing from theories of structural power and exchange, verified the hypotheses that the mechanisms, dynamics, and direction of violence in intimate relationships depends on the resources of each partner, the ratio of such resources, and their summative effects. Specifically, this study developed a framework that integrates the factors found related to domestic violence and defined as resources, and took into account their reward power, with reference to the status quo of the partners, to determine each partner's power within the relationship. The resources considered have included variables from four domains, individual, relational, social structural, and sociocultural. Existing gender-based …

Crash Quality- An Approach For Evaluating Spending On Quality Improvement Initiatives, Labiche Ferreira

Retrospective Theses and Dissertations

The quality movement has become popular among corporations big and small for one reason: empirical evidence suggests that quality and productivity (and hence profitability) are linked. Unfortunately, while many firms accept that quality and productivity go together, few actually track the gains associated with their quality improvement programs. Companies also tend to spend on quality improvement with no indication or estimation of the impact of funding on the targeted process. It would be of great value to know: (1) the impact of spending to enhance the product/process quality level, and (2) the point at which expenditures for quality improvement are …

Field Evaluation Of Ultrasound Enhancement Of Permeable Treatment Walls, Aamod Sudhakar Sonawane

Retrospective Theses and Dissertations

The objective of this research was to demonstrate the application of ultrasound to field sites having problems with precipitation build up and corrosion. PTW s are passive reactive walls containing zero-valent iron metal for in-situ remediation of contaminated groundwater. However, loss of reactivity over time due to build up of corrosion and other precipitates on the iron surface is a major concern. Ultrasound energy has been established as an effective tool for revitalizing iron surface. This research applied ultrasound energy to a zero-valent iron wall constructed below the ground surface to remove precipitates and iron corrosion, increasing iron reactivity. Two …

Signal Integrity In Deep Submicron Cmos Chip Design, Jignesh Suresh Sonchhatra

Retrospective Theses and Dissertations

Advancement in CMOS technology has become a driving force in the advancement of today's IC design arena. In the past few years, considerable research has been done on the CMOS devices and circuits. Constant efforts have been made to realize smaller and smaller devices by reducing the channel length of the transistors and scaling down various other device parameters. Consequently, various problems have arisen such as interconnect delay, signal integrity and signal coupling.

The purpose of this thesis is to review and understand current problems in IC design and come up with various solutions to them. Efforts have been made …

Optical Performance Of Grazing Incidence X-Ray / Euv Telescopes For Space Science Applications, Patrick Louis Thompson

Retrospective Theses and Dissertations

The science and technology of X-rays has only been part of human achievement for the past 100 years, while the study of image formation in general has endured for as long as 1000 years. The ability to conceive, design, and fabricate X-ray imagers, moreover, has existed for only the past 70 years, and X-ray astronomical telescopes have been in use for a mere 35 years. Considering that aplanatic, normal incidence telescope designs required more than 400 years to perfect, it is most interesting to note that the development of ‘aplanatic’ grazing incidence telescopes has taken only about 40 years. In …

Dynamic Modeling Of Pwm And Single-Switch Single-Stage Power Factor Correction Converters, Guangyong Zhu

Retrospective Theses and Dissertations

The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conductor losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). …

Combating Overpopulation : A Study Of The Population Policies Of China And India, Ariam J. Ferro

Retrospective Theses and Dissertations

With the world population now at 6 billion, the topic of overpopulation is becoming increasingly important. The planet cannot absorb an infinite number of humans, and steps need to be taken to combat unchecked growth. The thesis begins with a discussion of the problems currently manifesting themselves, including land degradation, water supply loss, farmland appropriation for living space, overfishing, and unequal food distribution. The thesis considers the population policy of China, long criticized by the West for its unusual harshness. In studying its history, though, it can be seen why the Chinese government felt radical steps were necessary. India's policy …

Design Considerations And Thermodynamic Feasibility Study Of A Meso-Scale Refrigerator, Nabil Shovon Ashraf

Retrospective Theses and Dissertations

Recent advances in micro-fabrication technology have ushered a new era in miniaturization of chemical, environmental and energy systems. This foreseeable trend towards miniaturization in chemical, environmental and mechanical systems is expected to revolutionize the ways the human life is being perceived today. The high volume and mass reproducibility is seen as the striking aspect of micro-fabrication based miniature systems, offering economies far exceeding than the economies of scale obtained in large plants. The focus of this thesis work is directed at the thermodynamic feasibility and preliminary prototype design for a meso-scale refrigerator. Miniaturization to sub-centimeter domain will enable configuring these …

An Intelligent Editor For Natural Language Processing Of Unrestricted Text, Demetrios George Glinos

Retrospective Theses and Dissertations

The understanding of natural language by computational methods has been a continuing and elusive problem in artificial intelligence. In recent years there has been a resurgence in natural language processing research. Much of this work has been on empirical or corpus-based methods which use a data-driven approach to train systems on large amounts of real language data. Using corpus-based methods, the performance of part-of-speech (POS) taggers, which assign to the individual words of a sentence their appropriate part of speech category (e.g., noun, verb, preposition), now rivals human performance levels, achieving accuracies exceeding 95%. Such taggers have proved useful as …

Application Of The Fdtd Method For The Analysis Of Finite-Sized Phased Array Microstrip Antennas, Javier Gomez Tagle Rangel

Retrospective Theses and Dissertations

The Finite-Difference Time-Domain (FDTD) method has gained tremendous popularity in the past decade as a tool for solving Maxwell's equations. Phased Array Antennas find several applications including mobile communications ( cellular, personal communication systems and networks), satellite communications, global positioning system (GPS), aeronautical and radar systems. This dissertation describes the application of the FDTD method for calculating broadband characteristics of finite-sized phased array antennas consisting of microstrip elements fed with coaxial probes.

The characterization of such antennas is dependent upon the development of simulation tools that can accurately model general topologies including wires, dielectrics, conductors lumped elements and metallic strips. …

The Effect Of Beach Nourishment On Loggerhead (Caretta Caretta) Nesting And Reproductive Success At Sebastian Inlet, Florida, Richard Michael Herren

Retrospective Theses and Dissertations

Beach nourishment has become common in Florida and it occurs on beaches that are major loggerhead (Caretta caretta) nesting grounds. Despite efforts to use beach-quality sand, nourishment sand may be different in grain size, moisture content, shear resistance and temperature when compared to native sand. Two main aspects of loggerhead nesting may be affected by nourishment. First, nourishment may reduce nesting success [(female nesting emergences/ female total emergences) X 100] due to physical barriers (i.e., scarps or steep cliffs) that can impede gravid females. Second, nourishment may reduce reproductive success {i.e., hatching success) by altering the nestsand environment. The objective …

Enterface: A Novella, Hubert Calip Mcleod

Retrospective Theses and Dissertations

A computer screen places each of us in an interface and virtual reality provides a totally simulated environment, a virtual world that we can enter. Enterface is a novella that examines the question first posed by Michael Heim: How far can we enter cyberspace and still remain human? It also explores the power and the limitation of language and the role of stories to shape reality in human life. Its themes are death, technology, ethics, and love. It is informed by Wittgensteinian philosophy, Norse mythology, and the "metaphysics of virtual reality."

The plot involves Moses Mackinow, a former Air Force …

The Working Relationship Of International Teaching Assistants And Undergraduate Students, Marcella A. Farina Phd

Retrospective Theses and Dissertations

The present study was conducted to ascertain undergraduate views about the effectiveness of International Teaching Assistants (ITAs) in the American classroom. The study was administered to a stratified cluster sampling by college of the target population, undergraduate students at the University of Central Florida, in Orlando, Florida. The instrument used, Questionnaire of Undergraduates about International Teaching Assistants (QUITA) as developed by Wanda Fox (1990), is composed of a total of 40 items regarding personal and academic background, cultural exposure to and views about non-native speakers of English, and ITA-classroom effectiveness and problem-solving strategies. On the basis of data from the …

Expectation And Satisfaction Of Freshmen And Seniors In Higher Education, Reuban Beryrl Rodriguez

Retrospective Theses and Dissertations

The purpose of this study was to examine the expectation, satisfaction and performance gap levels between selected freshman and seniors as measured by the selected SSI scales. The problem was to determine if expectation, satisfaction, and performance gap levels differed between freshman and seniors in 1995 and freshman and seniors in 1998 based on class level, gender and age. The study examined four selected scales from the twelve scales derived from the Student Satisfaction Inventory (SSI): Campus Climate, Campus Life, Campus Support Services, and Instruction Effectiveness. Respondents rated all items on a 7-point Likert scale with respect to their expectations …

Florida Social Studies Leaders' Perceptions Regarding An Afrocentric Curriculum, Vicki Kaplan Banks

Retrospective Theses and Dissertations

The purpose of this research study was to gain insight into the perceptions Florida's leaders have regarding the inclusion of an Afrocentric curriculum. The leaders chosen for this study were the Florida Council for the Social Studies Board and the Association of Social Studies Supervisors. These leaders were sent a questionnaire that contained 57 statements about social studies curriculum content in a Likert scale format. The results of the survey were reported by using mean scores and frequency distributions.

The Likert survey statements examined respondents' viewpoints with regard to diversity, Afrocentrism, and Eurocentrism. The results of the survey were used …

Parent Childrearing Beliefs And Child Externalizing Behaviors In Families Of Adhd And Odd Children, June E. Hoefling

Retrospective Theses and Dissertations

This study investigated the relationship between the perceived externalizing behaviors of children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) and the maladaptive childrearing beliefs of their parents. The study used archival survey data provided by Intervention Services, Inc., a community mental health center. Data from 338 families with a child diagnosed with ADHD or ODD were analyzed. The study used the Conners' Parent Behavior Rating Scale short version to measure the level of conduct problems, impulsivity, and hyperactivity of the children as perceived by the parents. The Adult-Adolescent Parenting Inventory was used to measure the degree of parental …

Numerical, Image, And Signal Processing Algorithms Applied To Radar Rainfall Estimation, John Eugene Lane

Retrospective Theses and Dissertations

Since the advent of radar in the 1940s, it has been well known that water drops composing precipitation scatter microwaves in a predictable manner. This characteristic of early. radar has lead to the present day Weather Surveillance Radar (WSR-88D) or NEXRAD systems, operated by the National Weather Service (NWS). In parallel to the evolution of weather radar for measuring precipitation over large areas, remote networks of rain gauges have been deployed and managed by agencies such as the Florida Water Management Districts. Since the recent deployment of the NWS network of WSR-88D, as well as the recent launch of the …