This thesis is concerned with the choice of the uncertainty structure in robust control problems. This choice affects the optimization carried out to obtain a robust feedback controller, and determines how robust a feedback loop will be to discrepancies in the parameters or dynamics of the plant model. Firstly, it presents readily applicable distance measures, robust stability margins and associated robust stability and robust performance theorems for several commonly used uncertainty structures for linear time-invariant systems (additive, multiplicative, inverse multiplicative, inverse additive, right coprime factor uncertainty).Secondly, the thesis discusses the robust stabilization problem for linear plants with a coprime factor uncertainty structure where the coprime factors of the plant are not necessarily normalized. The problem considered here is a generalization of the normalized coprime factor robust stabilization problem. It is shown that the minimum of the ratio of (non-normalized) coprime factor distance over (non-normalized) coprime factor robust stability margin, termed the robustness ratio, is an important bound in robust stability and performance results. A synthesis method is proposed which maintains a lower bound on the normalized coprimefactor robust stability margin (as a proxy for nominal performance) while also robustly stabilizing a particular perturbed plant, potentially far outside a normalized coprime factor neighbourhood of the nominal plant. The coprime factor synthesis problem is also considered in a state-space framework. It is shown that it admits a simple and intuitive controller implementation in observer form. Via the solution of one Riccati equation, an optimally robust observer gain L can be obtained for any state-feedback matrix F. One particular method for obtaining a suitable F is also proposed, ensuring that the feedback loop is particularly robust to uncertain lightly damped poles and zeros.

The purpose of this study is to examine faculty perceptions of instructional satisfaction and support when teaching distance education at a university located in the southeastern United States. Two research questions were included to determine what factors of instructional support faculty perceive as promoting/impeding their satisfaction when they participate in distance education, and to determine if there are any meaningful and significant relationships or differences between faculty perceptions of instructional satisfaction and demographic information. Data were collected via email using Google Docs, then compared to determine any significant difference in any of the categories. Descriptive statistics, independent t-tests, ANOVA, and the follow-up Tukey HSD test were used to determine if there were significant differences among faculty members in different demographic categories. Male participants are more satisfied with technology support, appropriate workload, and fair tenure process than females. Females are more satisfied than males with the potential growth opportunities. Overall Caucasians are more satisfied than African-Americans and participants aged 40-49 are more satisfied than any other age participants when teaching distance education. Generally, faculty with higher academic rank (Professor and Associate Professor) are more satisfied than lower academic rank faculty (Assistant Professor and Instructor). Tenured faculty are more satisfied than non-tenured faculty, and full-time faculty are more satisfied than part-time faculty. Participants who earned the highest salaries are more satisfied than participants earning lower salaries. Finally, generally the participants with more years of teaching experience were more satisfied than participants in the early years of their career. Tenure is a positive factor and factor workload is a negative factor impacting faculty satisfaction when teaching distance education.

Nitrogen use efficiency (NUE) and nitrogen (N) management practices have been an increasing concern among corn (Zea mays L.) producers. The objective of this study was to assess the placement distance of UAN and measure total N uptake on corn grain yield as affected by irrigation. Field trials were conducted in 2011 and 2012 at the Plant Science Research Center, Mississippi State, MS. Placement distance and irrigation influenced both total N uptake and grain yield results during both years of this study. Total N uptake and corn grain yield results were derived from plant samples and harvest data. Overall results from this study indicate increasing placement distance from the center of the planted row resulted in a decrease in total N uptake and grain yield. Results also show the subsurface banded treatment resulted in a greater N uptake and grain yield.

COVID-19 forced all education online during Spring 2020 requiring face-to-face higher education faculty to immediately redesign their courses for an online modality. This dissertation studied faculty who used Canvas as their Learning Management System to investigate how faculty leveraged affordances and navigated constraints of the platform, specifically in Pages and Assignments, when they designed and redesigned their courses; how their pedagogical and Canvas training affected their choices; and the ways in which their experiences affected their workload and stress levels. This study employed a three-phase methodology: a) a Qualtrics survey with open and closed-ended questions; b) 11 faculty were interviewed; and, c) Canvas course sandboxes of the interviewees were observed via Zoom. The results indicate that although the majority of faculty had some kind of pedagogical or Canvas training prior to the pandemic, they felt extreme stress and higher workload during spring, but lower stress and workload during summer as they prepared for fall since they had more time to work. The majority of faculty worked nonstop throughout 2020, even during their Spring Breaks and summer vacations; they did so without additional pay while writing, designing, and redesigning courses, and only a few faculty were paid for additional summer training. The research was analyzed through a convergent framework of Critical Digital Pedagogy, Interface, and Affordance theories, which formed the Pandemic Teaching Cycle and development of a new educational affordance taxonomy.

The purpose of the study was to examine the relationship between instructor interaction with students and retention in online classes in a rural community college classroom. The literature indicated that increased instructor/student interaction should lead to greater student satisfaction and retention in online instruction. The researcher operationalized interaction as announcements to the class, emails sent, amount of feedback given on assignments, and number of times the instructor logged into the course. Retention was measured by the number of students that successfully completed the class. Data were pulled from all online classes taught at Itawamba Community College during the fall 2013 semester. This data set included a total of 397 courses. Unique to this study was that all courses used standardized material that control for content delivery. This empirical study used a quantitative approach through a causal-comparative design. The statistics computed included descriptive statistics, Pearson’s product-moment correlation, and one-way ANOVA. In summary, the analysis did not support the research hypothesis in that there were no statistically significant differences in retention between the means of the instructors that met expected thresholds of the independent variables. Limitations in the current study may have influenced the outcome of the analysis and recommendations for further studies are discussed.

The present study sought to examine the teacher-efficacy for literacy instruction (TELI) of instructors who teach in an online environment. The phenomenological methodology sought to answer the following research questions: (1) What pedagogical practices do instructors use to provide literacy instruction in an online environment? (2) How do instructors perceive their TELI in an online environment? and (3) What impact, if any, will a Professional Learning Community (PLC) focused on Rosenblatt's Transactional Theory have on TELI in an online environment? The study consisted of a group of seven online instructors. The researcher the acting as facilitator administered the initial interviews and exit interviews and adapted an Action Research PLC with activities modeled after those that influence self-efficacy. In initial interviews, the participants described their literacy practices as mostly dialogic conversations with students in which they provide examples and non-examples for students. They used some aesthetic strategies, but their practices were mainly efferent and low taxonomically. The initial interviews also revealed that instructors felt that they did not know their students well and that their literacy instructional practices were mostly silenced by the dominant role of the standardized curriculum. It was observed that teachers sourced their confidence in TELI in an online environment not from the practices they used in an online environment, but in the practices they once used in the traditional classroom which are now silenced in an online environment. During the Action Research PLC, the researcher and participants collaborated in creating questions and instructional resources that helped students take a more aesthetic stance while still meeting the standards of the curriculum through the use of aesthetic questions and discussions, semantic association, and narrative-centered learning. The PLC structure also incorporated the four influential experiences on self-efficacy. The results of the exit interviews revealed that the teachers either remained confident or increased in confidence in their TELI in an online environment. In addition, viewing TELI through Rosenblatt's Transactional Theory aided in closing the gap in transactional distance observed by the participants because they were able to engage in more positive dialogues with their students. The PLC provided a creative space for teachers to work and deliver their personalized instruction enabling them to voice their once silenced literacy instructional practices. It can be determined that the transactions that teachers have with students mediated in an online environment have a far greater impact on TELI. Viewing literacy instruction through Rosenblatt's Transactional Theory provides a reflective experience where teachers revisit whether or not an instructional practice can improve their teaching through more aesthetic dialogue thus improving their TELI.

The admission process at higher education institutions has not adapted for online distance education classes taken in high schools, such as those offered by the Florida Virtual School. The purpose of this study was to determine whether online distance education courses taken in high school can serve as an indicator of student success in post-secondary education. An honors program at a large public research university provided the data examined. This honors program stored online distance education information in a database, which allowed for analysis. Presently, the institution's primary undergraduate admission office does not collect or store this type of information. I used SPSS Statistics to calculate logistical regression on this data. My goal was to discover what effect the high school online distance education variables had on the outcome of graduating in four or six years. Graduation rate is a key metric for colleges and universities as an indicator of success. For this reason, I wanted to determine through this study whether high school online distance education assisted in predicting which students will graduate. At least two stakeholders will find this information useful. Admission officers and, more specifically, honors admission officers will gain more insight into the student selection process as this study examines students in the top 10% of the incoming class. The other group, future researchers, will learn from this study and other new studies for even more understanding on this topic. Although the results indicated that high-achieving Florida Virtual School students do not graduate at higher rate than students who have not completed distance education classes, more research is required to understand how the other 90% of student applicants are affected by distance education courses completed in high school.

This study examined the impact of video feedback (VF) as a teaching tool for responding to writing activities and assignments across disciplines and whether or not VF can help instructors facilitate dialogic exchanges between students and teachers. I conducted three case studies with three different instructors from three different disciplines: psychology, history, and nanoscience. To determine the potential of video feedback to facilitate dialogic pedagogies, this dissertation examined the presence of transformational leadership theory (Parkin, 2017), the voices of teaching and learning (Collison et al., 2001), and gesture theory (Bavelas et al., 2014; Peräkylä & Ruusuvuori, 2008) for the paralinguistic activity in the VF content to determine if the presence of these theories position students as what Buber (1965) referred to as a "Thou" and dismantle the authoritative discourses (Bakhtin, 1994) in higher education that hinder learning. This dissertation found that teachers experienced meta-reflection and self-dialogue from making videos, which is dialogic. This study also found that instructors can facilitate dialogic exchanges that undermine authoritative discourses if they can utilize their paralinguistic activity that video affords them. This study also revealed that using VF requires overcoming a significant learning curve, and that Writing Across the Curriculum (WAC) can help teachers improve how they negotiate feedback variables like the assignment, discipline, pedagogy, and learning outcome that can lead to dialogic feedback.

The purpose of this study was two-fold, to understand student perception of the supplemental online courses and improve the online learning program at ABC Online Learning School. The study focused on students in Grades 6 -12 who belonged to the ABC School District and enrolled ABC Online Learning School high school credit courses to supplement their education. Student participants were asked to complete the Student Survey of Online Course Design. The data retrieved from the survey was analyzed using the Spearman correlation to establish the strength of the relationship between student perception of quality online course design and the importance of specific components of the online course. The results indicated that as student perception of quality increased, their perception of the importance of the component increased as well. Additionally, a logistic regression formula was used to test the ability to predict successful online course completions based on the developer of the online course (instructor-developed or vendor-developed) and the type of credit the student would earn based on completion (original credit or credit retrieval/recovery). The results of the analysis of the logistic regression showed that developer of the online course and type of credit earned did not have a significant influence on successful course completions. The study is significant because, in Florida, K-12 online courses are funded based on successful course completion and students are required to successful complete an online course to earn a high school diploma.

The goal of this thesis is to study the use of the Kantorovich-Rubinstein distance as to build a descriptor of sample complexity in classification problems. The idea is to use the fact that the Kantorovich-Rubinstein distance is a metric in the space of measures that also takes into account the geometry and topology of the underlying metric space. We associate to each class of points a measure and thus study the geometrical information that we can obtain from the Kantorovich-Rubinstein distance between those measures. We show that a large Kantorovich-Rubinstein distance between those measures allows to conclude that there exists a 1-Lipschitz classifier that classifies well the classes of points. We also discuss the limitation of the Kantorovich-Rubinstein distance as a descriptor.