Digital Commons Network^™

Frequency Domain Modeling And Optimal Parameter Tuning Of Power Converters For Dynamic Analysis Of The Grid Integration Of Photovoltaic Systems, Hussein Abdulrazzaq Lafta Alameri

Dissertations

Power electronic converters are essential devices for the effective interconnection of renewable energy sources to the power grid, such as DC-DC, DC-AC, and AC-DC converters. Therefore, power converter models that provide an accurate mathematical representation of their interconnection with other grid components are crucial for reliable transient and steady state analyses during normal or abnormal grid operating conditions.

This dissertation introduces a Laplace domain-based modeling approach for the study of transient converter-grid interactions. The proposed approach is based on the development of two-port admittance models of converters and other components, combined with the use of numerical Laplace transforms (NLT). The …

Predictors Of First-Time National Board Passage For Respiratory Therapists, Jennifer Kay Riggs

Dissertations

Respiratory therapists fulfill a vital role that saves and improves lives. To achieve recognition for their knowledge, unique skills, and dedication to clinical excellence, they must pass a series of national board exams. Achieving credentials from the National Board of Respiratory Care (NBRC) is a challenge, a true testament to the skills and strengths required for excellence in the profession. The problem prompting this study is the number of respiratory graduates who are not passing the Therapist Multiple Choice (TMC) exam on their first attempt. The goal of respiratory programs is to prepare graduates for success on the TMC exam …

Unsupervised Learning With Word Embeddings Captures Quiescent Knowledge From Covid-19 And Materials Science Literature, Tasnim H. Gharaibeh

Dissertations

Millions of scientific papers are produced each year and the scientific literature is continuing to grow at a head-spinning speed. Thus, massive scientific knowledge exists in solid text, but all these publications make it difficult, if not impossible, for researchers to keep in up to date with discoveries, even within a narrow scientific area. This massive amount of information also makes it difficult to find implicit and hidden connections, relationships, and dependencies within the information that may guide the direction of future research or lead to valuable new insights. So, there is a need for algorithms or models that can …

Cost-Effective Enablement Of Automated Driving Systems On Snow-Covered Roads, Nicholas Alan Goberville

Dissertations

The top reason for implementing automated driving features is to increase safety. Current deployed features like lane-keeping assist and adaptive cruise control have the ability to reduce collisions by up to 50%. However, due to perception limitations, these systems are only capable of operating in strict operational design domains. For example, the occlusion of lane lines introduced during winter weather conditions causes these safety systems to disengage. Companies targeting higher automated systems often use more expensive, high-fidelity sensors that may solve problems like this, but because of the high cost and minimal business model, deployments of such scope are unsustainable. …

Examining Academic Self-Efficacy, Race-Related Stress, Psychological Well-Being, And Racial Centrality On Black Former Undergraduate Historically Black College Students Currently Enrolled In Graduate Predominantly White Institutions, Maime Butler

Dissertations

The purpose of this study was to examine the relationships among racial centrality, racerelated stress, and psychological well-being on academic self-efficacy for Black former undergraduate HBCU and PWI students currently attending PWI graduate institutions. The following measures were used to test the research questions (a) a demographic questionnaire, (b) Mental Health Inventory (MHI; Viet & Ware, 1983), (c) Multidimensional Inventory of Black Identity – Racial Centrality Scale (MIBI; Sellers, 1998), (d) Inventory of Race-Related Stress- Brief Version (IRRS-B Utsey, 1999), (e) Graduate Education Self-Efficacy Scale (GESES; Williams, 2005). There were 200 participants, 74 former HBCU graduates and 126 former PWI …

Management Of Data Brokers In Support Of Smart Community Applications, Shadha Tabatabai

Dissertations

The widespread use of smart devices has led to the Internet of Things (IoT) revolution. Big data generated by billions of devices must be analyzed to make better decisions. However, this introduces security, communication, and processing problems. To solve these problems, we develop algorithms to enhance the work of brokers. We focus our efforts on three problems.

In the first problem, brokers are used in the cloud along with Software Defined Network (SDN) switches. We formulate minimizing brokers’ load difference within a reconfiguration budget with the constraint of indivisible topics as an Integer Linear Programming (ILP) problem. We show that …

Bayesian Credible Subgroup For Excess Zeroes, Daniel Nii Kwatei Quartey

Dissertations

A goal of subgroup analysis is to identify which subgroups of the population benefit from a given treatment. Traditional and also many recently introduced approaches to subgroup analysis that include statistical hypothesis testing of treatment-covariate interactions, prediction of personalized treatment effects via machine learning tree splitting algorithms, etc. do not explicitly address multiplicity issues. In this article, we extend the two–step Bayesian credible subgroups approach to assessment of heterogeneity in treatment effects and multiplicity-adjusted benefiting subgroup identification for zero–inflated count data, which are often encountered in medical and public health studies. Our approach is to conceptualize a zero–inflated Poisson regression …

Lost In The Cloud: The Experiences Of College Students With Visual Impairments In An Online Environment, Gwen A. Bostic

Dissertations

Online courses have become a necessity in education. Still, the online learning format, course design, and course management systems are not always conducive for learners with visual impairments. “A key concern is that faculty and individuals accountable for supporting and implementing e-learning within postsecondary institutions, in a rush to integrate technology into teaching, fail to think about the accessibility needs of students with various disabilities” (Fichten, 2009, p. 242).

This qualitative study aimed to describe and interpret the lived experiences of college students who are blind or visually impaired in an online environment. This study involved ten blind or low-vision …

The Role Of Motivation In Employee Disposition And Choosing To Act Among Manufacturing Employees: A Grounded Theory Of Discretionary Effort, Shawn Michael Andrews

Dissertations

Managers are often tasked to accomplish more with the resources at their disposal. Doing more with less is especially associated with the manufacturing industry providing a rich and relevant backdrop for study. Understanding discretionary effort as a resource, how it manifests, and when and how manufacturing employees choose to do more than is required is key to achieving results in an increasingly competitive and evolving industry. This constructive grounded research study investigated how 25 non-salaried manufacturing employees conceptualized how and why they chose to engage in activities that were considered above and beyond job role expectations. Extant literature was considered …

Factors Affecting Eighth Grade Students’ Mathematics Achievements In Timss 2015 In Abu Dhabi Emirate, Yousef Ahmed Wardat

Dissertations

This study aimed to identify the factors affecting mathematics achievement of eighth grade students in Trends in International Mathematics and Science Study (TIMSS, 2015) and to determine mathematics teachers' perceptions of TIMSS in Abu Dhabi Emirate schools. The first part of the study sample consisted of 4,838 students of grade eight (2,172 girls, 2,666 boys) and 156 respective school principals, and 220 mathematics teachers from Abu Dhabi, who attended TIMSS 2015. Study data was obtained from TIMSS 2015 student, teacher, school questionnaires, as well as cognitive test scores for mathematics. The second part of the study included data from 522 …

Behavior Of Steel Fiber Reinforced Concrete Made With Recycled Concrete Aggregates: Material Characterization And Deep Beam Shear Response, Nancy Kachouh

Dissertations

This research aims to examine the performance of concrete made with recycled concrete aggregates (RCAs) and steel fibers. It comprises material characterization tests, large-scale reinforced concrete (RC) deep beam tests, and numerical modeling. Material characterization test parameters included the RCA replacement percentage (30, 70, and 100%) and the steel fiber volume fraction (vf = 1, 2, and 3%). Fourteen large-scale deep beam numerical models with and without web openings made with 100% RCAs and steel fibers were developed and validated through a comparative analysis with test results. A numerical parametric study was conducted to investigate the effect of varying …

Stem Education:An Examination Of School Leaders’ And Teachers’ Perceptions On Stem Implementation In Uae Schools, Sara Elkeir Hamad

Dissertations

STEM education in the UAE is currently receiving growing attention due to the massive economic growth, which created a need for STEM-qualified graduates. Accordingly, UAE educational policymakers and curriculum developers advocate developing and implementing STEM education at all educational levels. The research emphasized that STEM education positively affects students’ ability to solve problems, be innovative, think critically, and be technology literate. This study aims to examine school leaders’ and STEM teachers’ perceptions of STEM implementation practices in the UAE context. A sequential explanatory, mixed-method design was employed to collect the data from the school’s leaders and teachers, quantitively using a …

Reflections On Professional Development: An Autoethnographic Study In Theories Of Practice, Sara Elizabeth Jennings

Dissertations

This autoethnographic project extends the work of Argyris and Schön (1974); Houchens (2008); Houchens and Keedy (2009); Houchens, Hurt, Stobaugh, & Keedy (2012); and Houchens, Stewart, and Jennings (2017) by replicating an experiment in reflective practice using a self-coaching protocol as a means for mapping one’s own theories of practice. Relying on selfreflexivity to study professional learning in a culture of school reform, the author used Argyris and Schon’s (1974) theories of practice as a conceptual framework by adapting a self-coaching protocol (Houchens, 2008; Houchens et al., 2012; Houchens et al., 2017) and pairing it with selfobservations of video-recorded instructional …

What Are The Factors Affecting African American High School Students' Decision For Applying To The University Of Central Florida?, Janet Martin

Dissertations

The number of African Americans enrolling in higher education has seen a steady decrease in recent years due to factors that act as barriers. This study examined these factors and their influence based on the students’ perspectives. The study design was based on the post-positivist paradigm and the quantitative methodology was used. Urban high school students were surveyed to determine their thoughts on the barriers they experienced as they applied to college. The Google survey included sixteen questions that required yes/no responses, Likert-scale responses, and short responses. The data were analyzed using logistic regression and Chi-square analysis. The results showed …

The Global Rise Of Online Devices, Cyber Crime And Cyber Defense: Enhancing Ethical Actions, Counter Measures, Cyber Strategy, And Approaches, Naresh Kshetri

Dissertations

The rise of online devices, online users, online shopping, online gaming, and online teaching has ultimately given rise to online attacks and online crimes. As cases of COVID-19 seem to increase day by day, so do online crimes and attacks (as many sectors and organizations went 100% online). Technological advancements and cyber warfare already generated many ethical issues, as internet users increasingly need ethical cyber defense strategies.

Individual internet users have challenges on their end; and on the other end, nation states (some secretly, some openly), are investing in robot weapons and autonomous weapons systems (AWS). New technologies have combined …

Delineating The Exocytic Fusion Machinery Required For Mast Cell Exocytosis, Pratikshya Adhikari

Dissertations

Mast cells undergo exocytosis to release a wide array of inflammatory mediators by utilizing membrane fusion proteins-SNAREs (soluble-N-ethyl-maleimide sensitive factor attachment protein receptor) along with essential regulatory Munc18 and Munc13 proteins. Accumulating evidence in mast cell biology suggests the existence of distinct pools of mast cell mediators. However, the precise mechanism underlying the release of each mast cell mediator is not clear. To determine whether different exocytic machineries are required for differential mediator release, I used reconstitution to investigate the differential role of Munc18s in fusion machinery regulation. Munc18a and Munc18c stimulated VAMP2 and VAMP3-mediated lipid mixing, whereas Munc18b only …

The Experiences And Expressions Of Compassion Among Critical Care Nurses, Mark S. Walker

Dissertations

Compassion is a core attribute of nursing practice and is associated with improved patient satisfaction and outcomes. For the last several decades, nurse researchers have been focused on the concept of compassion fatigue. Only recently has compassion appeared in nursing literature. Therefore, the purpose of this study was to explore the experiences and expressions of compassion among critical care nurses.

This dissertation includes a literature review of compassion within nursing education and practice, how it is currently defined, and a review of the empirical data. Next, two interpretative phenomenological qualitative studies were conducted. One study explored the experiences of compassion …

Examining The Relationship Between Therapists’ Attachment-Related Characteristics And The Process And Outcome Of Psychotherapy, Char M. Houben

Dissertations

Although psychotherapy researchers have gleaned greater understanding about how client attachment classifications influence the outcome of psychotherapy, relatively few studies have investigated therapists’ effects and have yielded inconclusive results (Steel et al., 2018). In the current study, we investigated how therapist attachment affects changes in the working alliance and client psychological distress over a course of psychotherapy treatment. We evaluated attachment in a sample of 23 therapist trainees from a university-based training clinic in the U.S. with the recently validated, transcript-based Therapist Attunement Scales (TASc; Talia & Muzi, 2017), which measures attunement by moment-to-moment discursive markers from a single psychotherapy …

Thermomechanics Of Semiconducting Polymers And Their Morphological Phenomena, Luke Galuska

Dissertations

In contrast to conventional silicon-based electronics, semiconducting polymers show great promise for emerging applications in soft, flexible, and ductile electronic technologies. This is due to their polymeric nature, tailorable structure, and sub-100 nm device thickness. Despite this mechanical novelty, there remains a poor understanding of their structure-property-processing relationships, which has hindered growth within the field. This dissertation elucidates these relationships through investigation of their thermomechanics, and morphological phenomena. This was accomplished through the following projects:

1) To demonstrate the impact of backbone rigidity on semiconducting polymer thermomechanics, we varied the backbone rigidity of an NDI-based polymer by inserting flexible methylene …

Comparing Top Industry Demands For Talent To General Studies Curriculum For Competitive Job Acquisition, Gregory Sansone

Dissertations

University General Studies degrees are rapidly increasing in enrollment, driven by an increased focus on college completion. Yet, non-traditional, non-science, technology, engineering, and math (STEM) degrees are perceived as less competitive in the job market upon graduation. This study finds that students predominantly acquire skills in three areas, analysis, critical thinking, and communication, regardless of courses taken. Variability in salary suggests that the degree was not a factor in the graduates’ ability for wage earning. Through a combination of skills outcomes for external job postings, natural language processing on course syllabi outcomes, General Studies graduates’ course records, and a survey …

The Color Of Conduct: A S.I.S.T.A.'S Tale Of Race, Housing, And Higher Education, Natasha Gibson-Winston

Dissertations

S.I.S.T.A., suffering in silence to be acknowledged, is an acronym that symbolizes the hidden voices of Black women in higher education and abroad. This study examined the experiences of a graduate student woman of color impacted by university housing policies and practices as a judicial student conduct officer at a historically white institution. Using autoethnography as a methodology, grounded in critical race theory (CRT) as a theoretical framework, this qualitative study aims to highlight the ways Black women can and have been harmed in predominantly white spaces and processes within higher education. The application of the aforementioned frameworks found the …

Applications Of Simulation Analysis To Generate Reference Points And Evaluate Management Control Rules In Three Eastern Us Fisheries, Laura Solinger

Dissertations

Myriad sources of uncertainty are characteristic of or impact all commercial and recreational fisheries, contributing uncertainty to the determination of stock status. In the face of these uncertainties, fisheries managers tend to reserve fishery resources from the management targets to allow for variability. Simulation analysis is a useful tool to complement and extend formal stock assessment models to better inform managers of the risk that a management strategy results in an overfished stock or overfishing occurs over some period of time. Three examples of simulation analysis are presented to address risk-tolerance and development of management thresholds for three commercially important …

Chlorhexidine Gluconate Bath Project: A Program Evaluation, Yavesh Crawford

Dissertations

Patients' safety outcomes are a reliable measure of how well a unit performs within any hospital. One of the most impactful patient safety factors is bloodline infections within the hospital. Blood line infections are associated with over 28,000 fatalities in the United States. The cost of central line bloodstream infection (CLABSI) in the United States is over $2 billion annually. Therefore, there is a need for a way to reduce CLABSI rates within care facilities. Considering the possible interventions, this program evaluation chose chlorhexidine gluconate (CHG) bathing to reduce infections. To establish the efficacy of the proposed solution, the program …

Radar Remote Sensing For Land Surface Studies Over The United Arab Emirates, Muhagir Hisham Elkamali

Dissertations

This dissertation is concerned with the land surface deformations related to anthropogenic activities and how a monitoring strategy can be established for nationwide studies. The main objective of this dissertation is to study land surface fluctuations in regional and local scales over the dry semi-arid climate of the United Arab Emirates with the relation to subsurface layers mechanisms and groundwater dynamics. Radar Interferometry techniques have been developed to detect and monitor land surface movement from space with very high accuracy. This dissertation investigates the implementation of these techniques over highly decorrelated surfaces. The detected land surface movements have been correlated …

An Investigation Of Single-Sex Classrooms In An Urban, Public School Ninth Grade Academy, Vivian Johnson

Dissertations

The American education system is continually in pursuit of equity, mirroring our nation’s pursuit of equity for citizens and non-citizens in all areas of life, liberty and the pursuit of happiness. There should not be discrimination towards any individual on the basis of sex, race, or physical disability. A person’s sex has always been a consideration within the confines of the American educational system. The question as to whether or not separating the sexes is advantageous for boys and girls to give them the opportunity to excel academically in the classroom learning environment is worth serious contemplation. Especially, when considering …

Correlation Of Personal Finance Class And Credit Scores, Betty W. Fagan

Dissertations

It is has become a concern: the number of people struggling with personal finance and credit scores. It is for this reason that this study scrutinizes the possible influence of one factor on the other. It is undeniable that personal finance influences some futuristic financial decisions and goals, but has the relationship been proven? This study aims to evaluate the correlation between personal finance and financial literacy, using a sample of 15 to 30 high-school students and teachers. The study collected data through interviews and surveys. The data collected were used to formulate the correlation between the course’s success and …

Predictors Of Retention And Passing National Council Licensure Examination For Registered Nurses, Nancy Susan Elkins

Dissertations

The current nursing shortage has challenged colleges to educate nurses at a faster pace than in previous times. Successful completion of the nursing programs and passing the National Council Licensure Examination for Registered Nurses (NCLEX-RN) exam is important for the students, faculty, and nursing programs. The purpose of this retrospective study was to investigate the possible predictors of completing the baccalaureate nursing program at a college in the eastern part of the United States and passing the NCLEX-RN licensure exam. Using Spearman's classical test theory and Seidman's retention formula as theoretical foundations, this study investigated historical data from 2 graduating …

Clinical Nurses Transitioning In A Faculty Role: A Cultural Analysis Of The Nursing Profession, The Academic Discipline Of Nursing, And The Academic Professorate, Cheryl L. Schriner

Dissertations

Nursing faculty are initially socialized into the culture of the nursing profession and then must transition into the culture of the academic discipline of nursing as they assume their new professorial role. This study explored how cultural similarities and differences influenced the transition of clinical nurses into a faculty role. The study was guided by Peterson and Spencer's (1990) model of organizational culture and Schlossberg's (1995) adult transition theory.

A Mixed-Methods Exploration Study On Trauma-Informed Practices Used To Dismantle The School-To-Prison Pipeline In Public And Private Schools In The City Of St. Louis, Jennifer Lauren Gabrian

Dissertations

Since the release of the Missouri Model for Trauma-Informed Schools approved by the Department of Elementary and Secondary Education (DESE) in 2019, school leaders were given the opportunity to start the process of meeting the emotional and fundamental needs of students. With the effects of trauma reaching all diverse groups of race, gender, economic status, and community surroundings, there is an increased need to use the education system to reach students emotionally. Though the model is a blueprint for schools, school districts are not required to adopt this model and implement it within their districts. Due to the recent pandemic, …

An Analysis Of Success Center Directors’ Perceptions Concerning College Remedial Education Programs, Melvin Steele Jr.

Dissertations

Success Centers are a component of community colleges that prepare students who need additional foundational coursework to proceed to college-level credit classes (Housel, 2020). In this study, the perceptions of Success Center Directors concerning their programs were explored through the lens of adult learning theory as advanced by Knowles and Lindeman (Merriam, 2018) using an online survey. Five research questions were investigated, which dealt with the services provided by Success Centers at community colleges, services that directors wanted to add, the credentials of those working in Success Centers, the impact of Success Centers on their stakeholders, and contingency plans used …