Dissertation Defense Announcements

Accurate knowledge and estimation of the electro-mechanical modes in the power system are of great importance since a system-wide outage can be caused by one single unstable mode of oscillation. Most of these unstable mode of oscillations are inter-area oscillations which typically are in the range of 0.15Hz to 1Hz. Generally oscillation identification and damping are performed based on Model-based frequency studies. However, the stochastic nature of modern power grid with the advent of renewables and changing load dynamics, and nonlinear interactions makes the oscillation study with apriori models inaccurate and inefficient. Due to these factors, recently, measurement-based power grid mode estimation has attracted great attention.

In this research work, a series of measurement-based oscillation identification methods are proposed. First, a comparison of various measurement-based electro-mechanical oscillation mode detection methods is studied. Among the measurement-based techniques, Prony analysis, Eigenvalue Realization Algorithm (ERA), and Matrix Pencil (MP) methods are found to be very useful. These methods have successfully been used to determine low-frequency oscillatory modes from measurement data. Recently, Subspace Identification (SSI) methods have become popular as they are robust to variations, and can be represented in state-space form, thus making it easier for designing time-domain control approaches. Thus, second, an online wide-area direct coordinated control architecture for power grid transient stability enhancement based on subspace identification and Lyapunov energy functions has been designed and studied. Third, a novel hybrid deterministic-stochastic online measurement-based identification framework using subspace theory is introduced. The novelty of the design using a fully recursive algorithm and the effectiveness of combined treatment are further discussed. For controlling electro-mechanical oscillations of the power system effectively, identifying the location of the oscillation source is very important. Thus, fourth, an approach for power system oscillatory mode estimation and classification and source location identification based on Lyapunov energy functions are proposed. This new method is then compared with the most commonly used method known as dissipated energy flow (DEF). Finally, this work explores grid following and grid forming control architecture of battery energy storage and the use of identification methods to observe low-frequency oscillation with Distributed Energy Resource (DER) connections.

ABSTRACT
TITUS L. HOPPER. Motivational Factors Affecting Black Male Principals in Rural North Carolina. (Under the direction of DR. REBECCA SHORE)

Many Black educators and principals led the nation’s schools in the early-to-mid-1900’s, when American public education was racially segregated. Black male principals leading predominantly Black schools was commonplace before the United States Supreme Court’s decision in Brown v. Board of Education that ruled that the practice of separate was no longer equal. The number of Black male principals serving in North Carolina schools today is disproportionately low. Research on rural schools is scant and there is even less research about Black male principals leading these schools. This study focused on the motivational factors affecting Black male principals working in rural North Carolina school districts. The purpose of this basic, interpretive qualitative case-study was to explore the lived experiences of these principals. As part of this exploration, the researcher examined factors that motivated Black male principals to work in rural North Carolina counties. All five participants in the study expressed that they embraced their profession and work as a major component of their identity; four were native to their rural communities. They believed they had a moral obligation to serve as a mirror, a window, and an advocate for rural North Carolina students and prove that Black male principals were educational leaders and more than disciplinarians. Job dissatisfaction factors included the low expectations and deficit perceptions of schools and students from rural counties in North Carolina, as well as the inequitable distribution and access to human capital and resources. The researcher’s hope is that insight gained from this investigation would positively impact recruiting, mentoring, coaching of Black male principals, and aid in their retention not only in rural districts, but potentially all districts.

Students experience many stressors that impact their academic achievement and overall well-being. Therefore, schools must explore methods to help students address stressors and to focus on academic learning. In the age of school accountability for academic growth and stagnant or shrinking budgets, schools must explore options that are fiscally possible and have a limited impact on school schedule. Mindfulness is a practice that claims to help students focus in on the learning environment at school in cost-effective and manageable ways.
The purpose of this quantitative study was to analyze the impact of participation in Inner Explorer, an audio-guided, online, mindfulness-based intervention on the academic growth of students. Specifically, the researcher aimed to examine the impact of Inner Explorer on elementary school students in traditional classrooms and to also analyze the impact on students with disabilities. The study consisted of 378 students in second through fifth grades across two schools. A split-plot analysis of variance was used to gauge the impact of Inner Explorer on academic growth for all students and to focus on students with disabilities. Findings suggest that student participation in the Inner Explorer program did not have a significant impact on academic growth. In addition, students with disabilities did not gain academically because of participation in the Inner Explorer program. While previous research suggested a positive relationship between mindfulness and students’ well-being, results of this study did not demonstrate a large-scale impact on academic growth. However, there were aspects within the data that can be attributed to participation in the Inner Explorer program. Further analysis of the impact of mindfulness on academic performance would require a more in-depth research approach spanning a longer timespan than that used in this study. In addition, the concept would best be researched using a larger sample to explore the impact on sub-groups of student populations.

As schools adapt curriculum and learning environments to better prepare students for entry into an increasingly globalized society, cultivating intercultural competencies in K-12 in-service educators is of heightened importance. The purpose of this study was to develop and validate a new instrument designed to assess these competencies called the Intercultural Competency Measure for Educators (ICME). Byram (1997) defines intercultural competencies as the ability to effectively communicate, understand, and work with people from diverse cultural backgrounds. Deardorff (2006) adds to this a call for action, which lends itself to the critical cosmopolitanism framework that guides this study. A pilot study was used to develop a four-factor theoretical intercultural competencies framework through a process defined in this study. Reliability and validity were examined using data collected from K-12 in-service educators at schools in the United States and Canada. An Exploratory Factor Analysis suggested a revision of the constructs to include five factors: Curriculum, Diverse Student Inclusion, Cross-Cultural Openness, Collaboration and Adaptation, and Systematic Awareness. Construct validity was tested using Confirmatory Factor Analysis and supported by examining demographic data using parametric tests. The emergence of a factor related to systematic awareness highlights teachers' increased role in addressing the root causes of inequity in schools. The five-factor model provides a framework for schools wishing to further develop and assess intercultural competencies growth in teachers.