UNT Theses and Dissertations - Browse

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Exploring Memristor Based Analog Design in Simscape

Description: With conventional CMOS technologies approaching their scaling limits, researchers are actively investigating alternative technologies for ever increasing computing and mobile demand. A number of different technologies are currently being studied by different research groups. In the last decade, one-dimensional (1D) carbon nanotubes (CNT), graphene, which is a two-dimensional (2D) natural occurring carbon rolled in tubular form, and zero-dimensional (0D) fullerenes have been the subject of intensive research. In 2008, HP Labs announced a ground-breaking fabrication of memristors, the fourth fundamental element postulated by Chua at the University of California, Berkeley in 1971. In the last few years, the memristor has gained a lot of attention from the research community. In-depth studies of the memristor and its analog behavior have convinced the community that it has the potential in future nano-architectures for optimization of high-density memory and neuromorphic computing architectures. The objective of this thesis is to explore memristors for analog and mixed-signal system design using Simscape. This thesis presents a memristor model in the Simscape language. Simscape has been used as it has the potential for modeling large systems. A memristor based programmable oscillator is also presented with simulation results and characterization. In addition, simulation results of different memristor models are presented which are crucial for the detailed understanding of the memristor along with its properties.
Date: May 2013
Creator: Gautam, Mahesh
Partner: UNT Libraries

Spirituality, health locus of control, and wellness in organizational health promotion and wellness programs

Description: The relationship between an individual's level of spirituality, health locus of control, and participating in wellness activity was investigated. The relationship between spirituality, health locus of control on physical health was also investigated. The research question was based on prior studies that reported people who are more spiritual are healthier. Does their spirituality lead to increased levels of health, or are individual's who are more spiritual more likely to proactively take control of their health and engage in health promoting behaviors? One hundred and fifteen male and female employees completed The Spiritual Involvement and Beliefs Scale (SIBS), a spirituality measure, The Multidimensional Health Locus of Control Scale, a measure of locus of control related to health and healthcare, and The Center for Disease Control's (CDC) Health Risk Appraisal, a self-report measure of participation in health behaviors. Physical measures of health were obtained by obtaining Body Mass Index, blood pressure readings, and a cholesterol screening. The current study looked at level of spirituality (internal, external), level of health locus of control (internal, powerful other, chance) and participation in wellness/health promoting behaviors and health. Correlational analyses were performed on the relationship between spirituality and health locus of control. Hierarchical multiple regressions were performed on the internal spirituality and internal health locus of control to examine the relationship between spirituality, health locus of control and positive health behaviors and level of physical health. Stepwise discriminant function analysis using spirituality and health locus of control as predictor variables for the health-behavior criterion variables were performed. Discussion of the results, limitations of the current study and recommendations for future research were presented.
Date: August 2001
Creator: Gauthier, Janine E.
Partner: UNT Libraries

Alberto Ginastera and the Guitar Chord: An Analytical Study

Description: The guitar chord (a sonority based on the open strings of the guitar) is one of Alberto Ginastera's compositional trademarks. The use of the guitar chord expands throughout forty years, creating a common link between different compositional stages and techniques. Chapters I and II provide the historical and technical background on Ginastera's life, oeuvre and scholar research. Chapter IV explores the origins of the guitar chord and compares it to similar specific sonorities used by different composers to express extra-musical ideas. Chapter V discusses Ginastera's initial uses and modifications of the guitar chord. Chapter VI explores the use of the guitar chord as a referential sonority based on Variaciones Concertantes, Op. 23: I-II, examining vertical (subsets) and horizontal (derivation of motives) aspects. Chapter VII explores uses of trichords and hexachords derived from the guitar chord in the Sonata for Guitar Op. 47.
Date: December 2010
Creator: Gaviria, Carlos A.
Partner: UNT Libraries

Carlo Milanuzzi's Quarto Scherzo and the Climate of Venetian Popular Music in the 1620s

Description: Although music publishing in Italy was on the decline around the turn of the seventeenth century, Venice emerged as one of the most prolific publishing centers of secular song in Italy throughout the first three decades of the 1600s. Many Venetian song collections were printed with alfabeto, a chordal tablature designed to facilitate even the most untrained of musicians with the necessary tools for accompanying singers on the fashionable five-course Spanish guitar. Carlo Milanuzzi's Quarto Scherzo (1624) stands out among its contemporary Venetian song collections with alfabeto as an anthology of Venetian secular songs, including compositions by Miniscalchi, Berti, and Claudio and Francesco Monteverdi. Issues surrounding its publication, instrumentation, and musical and poetic style not only contribute to the understanding of Venetian Baroque monody, but also help to construe a repertory of vocal music with defining characteristics usually associated with popular music of the 19th, 20th, and 21st centuries.
Date: August 2001
Creator: Gavito, Cory Michael
Partner: UNT Libraries

Examination of the Alignment between the SHRM Competency Model and Undergraduate Syllabi of Human Resources and Management Degree Programs in Texas

Description: The purpose of this study was to provide a snapshot of current Human Resources (HR) and Management curricula of four-year public universities in Texas in 2016 and evaluate their alignment with the competencies of the SHRM Competency Model®. This study used a mixed methods approach and analyzed course syllabi for a purposeful sample of 21 public universities in Texas. The course objectives referenced explicitly and/or implicitly all nine competencies. Three courses encompassed all nine competencies, and 84% of all programs demonstrated alignment with the competencies. “Business Acumen”, “Critical Evaluation”, “Communication” and “Relationship Management” were the most frequently referenced competencies in course syllabi. “Consultation” appeared the least frequently. This comprehensive analysis revealed that there is alignment between course curricula of public universities in Texas and competency expectations of graduates wishing to pursue a career in Human Resources. Recommendations applied to four areas including scholarship, university administration, professional associations, and practitioners.
Date: May 2016
Creator: Gavrilova Aguilar, Mariya C
Partner: UNT Libraries

Alternate Substrates and Isotope Effects as a Probe of the Malic Enzyme Reaction

Description: Dissociation constants for alternate dirmcleotide substrates and competitive inhibitors suggest that the dinucleotide binding site of the Ascaris suum NAD-malic enzyme is hydrophobic in the vicinity of the nicotinamide ring. Changes in the divalent metal ion activator from Mg^2+ to Mn^2+ or Cd^2+ results in a decrease in the dinucleotide affinity and an increase in the affinity for malate. Primary deuterium and 13-C isotope effects obtained with the different metal ions suggest either a change in the transition state structure for the hydride transfer or decarboxylation steps or both. Deuterium isotope effects are finite whether reactants are maintained at saturating or limiting concentrations with all the metal ions and dinucleotide substrates used. With Cd^2+ as the divalent metal ion, inactivation of the enzyme occurs whether enzyme alone is present or is turning over. Upon inactivation only Cd^2+ ions are bound to the enzyme which becomes denatured. Modification of the enzyme to give an SCN-enzyme decreases the ability of Cd^2+ to cause inactivation. The modified enzyme generally exhibits increases in K_NAD and K_i_metai and decreases in V_max as the metal size increases from Mg^2+ to Mn^2+ or Cd^2+, indicative of crowding in the site. In all cases, affinity for malate greatly decreases, suggesting that malate does not bind optimally to the modified enzyme. For the native enzyme, primary deuterium isotope effects increase with a concomitant decrease in the 13-C effects when NAD is replaced by an alternate dinucleotide substrate different in redox potential. This suggests that when the alternate dinucleotides are used, a switch in the rate limitation of the chemical steps occurs with hydride transfer more rate limiting than decarboxylation. Deuteration of malate decreases the 13-C effect with NAD for the native enzyme, but an increase in 13-C effect is obtained with alternate dinucleotides. These suggest the presence of a ...
Date: August 1988
Creator: Gavva, Sandhya Reddy
Partner: UNT Libraries

Fluorescence labeling and computational analysis of the strut of myosin's 50 kDa cleft.

Description: In order to understand the structural changes in myosin S1, fluorescence polarization and computational dynamics simulations were used. Dynamics simulations on the S1 motor domain indicated that significant flexibility was present throughout the molecular model. The constrained opening versus closing of the 50 kDa cleft appeared to induce opposite directions of movement in the lever arm. A sequence called the "strut" which traverses the 50 kDa cleft and may play an important role in positioning the actomyosin binding interface during actin binding is thought to be intimately linked to distant structural changes in the myosin's nucleotide cleft and neck regions. To study the dynamics of the strut region, a method of fluorescent labeling of the strut was discovered using the dye CY3. CY3 served as a hydrophobic tag for purification by hydrophobic interaction chromatography which enabled the separation of labeled and unlabeled species of S1 including a fraction labeled specifically at the strut sequence. The high specificity of labeling was verified by proteolytic digestions, gel electrophoresis, and mass spectroscopy. Analysis of the labeled S1 by collisional quenching, fluorescence polarization, and actin-activated ATPase activity were consistent with predictions from structural models of the probe's location. Although the fluorescent intensity of the CY3 was insensitive to actin binding, its fluorescence polarization was notably affected. Intriguingly, the mobility of the probe increases upon S1 binding to actin suggesting that the CY3 becomes displaced from interactions with the surface of S1 and is consistent with a structural change in the strut due to cleft motions. Labeling the strut reduced the affinity of S1 for actin but did not prevent actin-activated ATPase activity which makes it a potentially useful probe of the actomyosin interface. The different conformations of myosin S1 indicated that the strut is not as flexible as several other key regions of myosin ...
Date: August 2007
Creator: Gawalapu, Ravi Kumar
Partner: UNT Libraries

A Study of the Effects of Frequency Variance on Duration Perception

Description: This study investigates the effects of frequency variance on duration perception, using musically trained subjects. In the experiment three silent duration intervals were examined (4.75, 5.00, and 5.25 seconds); each interval was preceded and followed by tone markers. The onset marker was preceded by seven discrete tones one second apart, on the frequency 174.968 Hertz. This established a pulse or an external standard time measure. The subjects made judgments as to whether the offset marker fell "before," "on," or "after," the pulse. The offset marker had a variable frequency. In the study, the direction of the frequency change, the distance of frequency change, and the mathematical intervallic relationships of the two frequencies show possible influence on duration perception.
Date: May 1980
Creator: Gay, Leslie C.
Partner: UNT Libraries

A Comparison Between Reading and Listening in Comprehension and Retention of Certain Language Concepts in the Third Grade

Description: This thesis compares reading verses listening comprehension in third grade students. The problem under consideration is to determine whether it is easier for a third-grade child to understand a given meaning when that meaning is presented to him in spoken words than it is when the meaning is presented in printed words,
Date: August 1950
Creator: Gay, Marcella
Partner: UNT Libraries

Jeans, Boots, and Starry Skies: Tales of a Gay Country-and-Western Bar and Places Nearby

Description: Fourteen short stories, with five interspersed vignettes, describe the lives of gay people in the southwestern United States, centered around a fictional gay country-and-western bar in Dallas and a small town in Oklahoma. Various characters, themes, and trajectories recur in the manner of a short story cycle, as explained in the prefatory Critical Analysis, which focuses on exemplary works of James Joyce, Ernest Hemingway, William Faulkner, Shirley Jackson, Italo Calvino, Yevgeny Kharitonov, and Louise Erdrich.
Date: May 2010
Creator: Gay, Wayne Lee
Partner: UNT Libraries

Short Stories

Description: This collection of seven representative original short stories will include four short stories relating to a fictional location in Dallas, the Starry Skies gay country-and-western dance hall. Three short stories set in fabulous, sometimes absurd settings, will follow. A preface dealing with the nature of fictional place and non-fictional place in fiction will precede the collection of short stories.
Date: December 2007
Creator: Gay, Wayne Lee
Partner: UNT Libraries

Shoot the Messenger or Change the Message: What are African American Men Learning About Choosing College?

Description: This study identified and described the experiences of twelve African American men that influenced the choice to participate in postsecondary education. This qualitative study used a phenomenology framework to determine 1) the formation of predisposition in the college choice process, 2) the messages received about college from influential people, and 3) perception and interpretation of the importance of a college degree. The overall theme arising from the data is that the college choice process was complicated and inconsistent; however, ten of the twelve participants completed some type of postsecondary training. Deficient messages about postsecondary education manifested as low parental support for college attendance, low academic expectations, withholding of important information from school officials and little or no exposure to postsecondary institution campuses or students. Influential people for the participants ranged from parents to themselves, and from a combination of characteristics from different people, to peers, to no one. The informants did not consistently identify their role model as the one who influenced them to attend college. The perception of the value of a college degree varied among the participants. Some described the degree as a requirement for success; others felt that strengthening family and achieving financial independence was more important.
Date: December 2005
Creator: Gayden, Kizuwanda Balayo
Partner: UNT Libraries

Factors Affecting Resistance to Change: A Case Study of Two North Texas Police Departments

Description: This study focuses on four common factors believed to affect resistance to change in public organizations. It contributes to existing literature by examining the effect of higher education and trust on the police officer's level of resistance to change and the effects of participation and communication on trust. 286 police officers from two north Texas towns responded to the survey. Regression analysis and bivariate correlations were used to determine the relationship between, resistance to change, and participation, trust, communication, information, and education and the relationship between trust and the other independent variable. The analysis failed to support previous research, which listed participation as the most important factor, but did support the concept that participation and communication improved trust.
Date: May 2001
Creator: Gaylor, Thomas Kent
Partner: UNT Libraries

Flexible Digital Authentication Techniques

Description: Abstract This dissertation investigates authentication techniques in some emerging areas. Specifically, authentication schemes have been proposed that are well-suited for embedded systems, and privacy-respecting pay Web sites. With embedded systems, a person could own several devices which are capable of communication and interaction, but these devices use embedded processors whose computational capabilities are limited as compared to desktop computers. Examples of this scenario include entertainment devices or appliances owned by a consumer, multiple control and sensor systems in an automobile or airplane, and environmental controls in a building. An efficient public key cryptosystem has been devised, which provides a complete solution to an embedded system, including protocols for authentication, authenticated key exchange, encryption, and revocation. The new construction is especially suitable for the devices with constrained computing capabilities and resources. Compared with other available authentication schemes, such as X.509, identity-based encryption, etc, the new construction provides unique features such as simplicity, efficiency, forward secrecy, and an efficient re-keying mechanism. In the application scenario for a pay Web site, users may be sensitive about their privacy, and do not wish their behaviors to be tracked by Web sites. Thus, an anonymous authentication scheme is desirable in this case. That is, a user can prove his/her authenticity without revealing his/her identity. On the other hand, the Web site owner would like to prevent a bunch of users from sharing a single subscription while hiding behind user anonymity. The Web site should be able to detect these possible malicious behaviors, and exclude corrupted users from future service. This dissertation extensively discusses anonymous authentication techniques, such as group signature, direct anonymous attestation, and traceable signature. Three anonymous authentication schemes have been proposed, which include a group signature scheme with signature claiming and variable linkability, a scheme for direct anonymous attestation in trusted computing platforms ...
Date: May 2006
Creator: Ge, He
Partner: UNT Libraries

A Study to Develop a Curriculum in Industrial Destructive Testing Procedures for Ferrous and Non-Ferrous Metals at the University Level

Description: The problem of this study was to develop a curriculum based on present destructive testing procedures used in industry dealing with the mechanical properties of ferrous and non-ferrous metals, and to organize the curriculum at the university level.
Date: May 1971
Creator: Geary, Michael Robert
Partner: UNT Libraries

A Study and Critique of the Mean Position Concept in Relativistic Wave Mechanics

Description: The basic concept to be used in studying the question of one-particle interpretations of relativistic wave equations is that of observables and operator representations that are different from the more usual classically motivated observables and representations. In particular, the concept of a mean-position observable will be used to determine to what extent the one-particle "problems" can be resolved.
Date: January 1967
Creator: Gebhart, Hugh David
Partner: UNT Libraries

Childhood Learning: Examining Attitudes toward School and Learning Ability

Description: A child's ability to learn in school and school performance are affected by various factors. Variables that affect learning and academic performance in 46 children, 4 - 7 years old, were examined. Children, parents, and teachers completed questionnaires rating children's attitudes and behavior toward school. Children completed a computerized matching-to-sample (MTS) task. The MTS trained the children to form 3 stimulus classes. One stimulus class included three arbitrary stimuli, the others contained a positively or negatively valenced stimulus, a school-related stimulus, and an arbitrary stimulus. Class formation performance was assessed. Rate of learning predicted attitudes toward school, school attitudes predicted academic performance; however a hypothesized mediation effect of attitudes was not demonstrated. No significant differences in rate of forming stimulus classes containing emotionally valenced and school stimuli were found. Future directions for intervention in the early education of students who have poor attitudes toward school are discussed.
Date: May 2009
Creator: Geddes, Jeffrey D.
Partner: UNT Libraries

Risk and Resilience Faced by Children of Deployed Service Members

Description: The purpose of this study was to examine the impact of military deployment on children, and the roles that risk and protective factors and parenting stress play in emotional symptoms and behaviors exhibited by children while their parents are deployed. A sample of 143 parents (recruited from all branches of the military) who remained at home while their spouses were deployed completed online self-report questionnaires measuring demographic and background information, child internalizing and externalizing behavior, parenting stress, child adaptability, valuing behavior, family cohesion/environment, and parenting behaviors. The sample primarily consisted of mothers (n = 141) and Caucasian individuals (n = 126), which may limit the generalizability of the findings. Results of the study suggest risk factors including parenting stress, corporal punishment, length of time a parent is deployed, and type of deployment (combat vs. non-combat) were predictive of poorer child outcomes. Protective factors including values consistent behavior, child adaptability, and family cohesion were predictive of better childhood outcomes. Parenting stress served as a mediating variable between the relationship of total risk and child outcomes, while values consistent behavior served as a mediating variable between the relationship of protective factors experienced by children and child outcomes. Military deployments not only impact the service members, but also their families at home. Further study and identification of risk and protective factors faced by military children and families are imperative. Implications of findings are discussed as well as suggestions for future research concerning deployment and impact on military families (e.g. identification and empirical validation of programs to support military families.
Date: August 2011
Creator: Geddes, Jeffrey D.
Partner: UNT Libraries