Digital Commons Network^™

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 …