Significant research efforts have been devoted to large-scale dynamical systems, with the aim of understanding their complicated behaviors and managing their responses in real-time. One pivotal technological obstacle in this process is the existence of uncertainty. Although many of these large-scale dynamical systems function well in the design stage, they may easily fail when operating in realistic environment, where environmental uncertainties modulate system dynamics and complicate real-time predication and management tasks. This dissertation aims to develop systematic methodologies to evaluate the performance of large-scale dynamical systems under uncertainty, as a step toward real-time decision support. Two uncertainty evaluation approaches are pursued: the analytical approach and the effective simulation approach. The analytical approach abstracts the dynamics of original stochastic systems, and develops tractable analysis (e.g., jump-linear analysis) for the approximated systems. Despite the potential bias introduced in the approximation process, the analytical approach provides rich insights valuable for evaluating and managing the performance of large-scale dynamical systems under uncertainty. When a system’s complexity and scale are beyond tractable analysis, the effective simulation approach becomes very useful. The effective simulation approach aims to use a few smartly selected simulations to quickly evaluate a complex system’s statistical performance. This approach was originally developed …

The subject of this manuscript is the Texas Rangers “clean-up” of San Augustine, which was undertaken between late January 1935 until approximately July 1936 at the direction of then newly-elected Governor James V. Allred, in response to the local “troubles” that arose from an near decade long “crime wave.” Allred had been elected on a platform advocating dramatic reform of state law enforcement, and the success of the “clean-up” was heralded as validation of those reforms, which included the creation of – and the Rangers’ integration into – the Texas Department of Public Safety that same year. Despite such historic significance for the community of San Augustine, the state, and the Texas Rangers, no detailed account has ever been published. The few existing published accounts are terse, vague, and inadequate to address the relevant issues. They are often also overly reliant on limited oral accounts and substantially factually flawed, thereby rendering their interpretive analysis moot in regard to certain issues. Additionally, it is a period of San Augustine’s history that haunts that community to this day, particularly as a result of the wide-ranging myths that have taken hold in the absence of a thoroughly researched and documented published account. Concerns …

This study examined differences between adult first-generation (AFG) and adult-continuing generation (ACG) students’ academic self-efficacy with regard to the online courses in which they were currently enrolled. The study used an online survey methodology to collect self-reported quantitative data from 1,768 undergraduate students enrolled in an online course at a mid-sized, four-year public university in the southwestern United States; 325 cases were usable for the study. The t-tests revealed no statistically significant differences between the academic self-efficacy of the AFG and ACG students. Parents’ level of educational attainment was unrelated to adult students’ academic self-efficacy with online courses. Ordinary least-squares analysis was used to evaluate student characteristics that might be associated with academic self-efficacy in the online environment. A combination of gender, GPA, age, race/ethnicity (White, Black, Hispanic, and other), and number of previous online courses predicted a statistically significant 12% of the variance in academic self-efficacy in an online environment (p < .001). Age (p < .001) and self-efficacy were positively correlated, meaning that adult students reported greater academic self-efficacy than did younger students; and number of previous online courses (p < .001) was also positively correlated to academic self-efficacy, indicating that students with greater experience with online courses …

Compared to the general population, diabetic patients experience a higher prevalence of depression, which can often exacerbate diabetic symptoms and complicate treatment. Studies show that religion is associated with both better physical health and better psychological functioning; however, studies incorporating religion and depression among diabetic individuals are scarce. The present study addressed this gap in the literature by examining archival data from the 2008 and 2010 data waves of the Health and Retirement Study (HRS). Cross-sectional findings confirmed that stronger religiosity was positively correlated with perceived diabetes control and positive diabetes change, and negatively correlated with total number of depressive symptoms and total number of weeks depressed. Longitudinal findings confirmed that stronger religiosity in 2008 was positively correlated with perceived diabetes change in 2010 and negatively correlated with total number of depressive symptoms in 2010. Logistic regression and multiple regression analyses were performed to test four moderation models. Results showed that religiosity significantly moderated the relationship between perceived diabetes control and total number of weeks depressed. More specifically, for diabetics with low levels of religiosity, whether they believed their diabetes was under control or not did not make a significant difference in the total number of weeks depressed. However, high …

Current energy and environmental challenges are driving the use of cellulosic materials for biofuel production. A major obstacle in this pursuit is poor ethanol tolerance among cellulolytic Clostridium species. The first objective of this work was to establish a potential upper boundary of ethanol tolerance for the cellulosome itself. The hydrolytic function of crude cellulosome extracts from C. cellulolyticum on carboxymethyl cellulose (CMC) with 0, 5, 10, 15, 20 and 25% (v/v) ethanol was determined. Results indicated that the endoglucanase activity of the cellulosome incubated in 5% and 10% ethanol was significantly different from a control without ethanol addition. Furthermore a significant difference was observed in endoglucanase activity for cellulosome incubated in 5%, 10%, 15%, 20% and 25% ethanol in a standalone experiment. Endoglucanase activity continued to be observed for up to 25% ethanol, indicating that cellulosome function in ethanol will not be an impediment to future efforts towards engineering increasing production titers to levels at least as high as the current physiological limits of the most tolerant ethanologenic microbes. The second objective of this work was to study bioethanol production by a microbial co-culture involving Clostridium cellulolyticum and a recombinant Zymomonas mobilis engineered for the utilization of oligodextrans. The …

This research seeks to derive and examine a multidimensional definition of information security awareness, investigate its antecedents, and analyze its effects on compliance with organizational information security policies. The above research goals are tested through the theoretical lens of technology threat avoidance theory and protection motivation theory. Information security awareness is defined as a second-order construct composed of the elements of threat and coping appraisals supplemented by the responsibilities construct to account for organizational environment. The study is executed in two stages. First, the participants (employees of a municipality) are exposed to a series of phishing and spear-phishing messages to assess if there are any common characteristics shared by the phishing victims. The differences between the phished and the not phished group are assessed through multiple discriminant analysis. Second, the same individuals are asked to participate in a survey designed to examine their security awareness. The research model is tested using PLS-SEM approach. The results indicate that security awareness is in fact a second-order formative construct composed of six components. There are significant differences in security awareness levels between the victims of the phishing experiment and the employees who maintain compliance with security policies. The study extends the theory by …

Professionals in education continue to explore technology as a way to instruct young students, and there is an accompanying belief that this technology can make an educational and academic difference. Despite the high percentage of young students in classrooms using technology, the impact of this technology on the early literacy skills of young children remains largely unknown. Guided by Vygotsky’s social learning theory, this study reports a 24-week investigation on whether regular use of Istation®, an integrated learning system used by approximately 3,000,000 students in the United States, had an effect on the early literacy achievement of children in twelve kindergarten classrooms. A mixed-method, quasi-experimental design was constructed using propensity scores. Also investigated were the effects of the level of teacher literacy support on early literacy achievement and the interaction between Istation® use and the level of teacher literacy support. A descriptive discriminant analysis was performed to determine the main effect of Istation®. The level of teacher support and the interaction effect was then tested using a multivariate between-subject analysis. Results indicated that Istation® did have a statistically significant effect on the early literacy skills of the 72 kindergarten students studied and was able to explain 17.7% of the variance …

A steepest descent method is constructed for the general setting of a linear differential equation paired with uniqueness-inducing conditions which might yield a generally overdetermined system. The method differs from traditional steepest descent methods by considering the conditions when defining the corresponding Sobolev space. The descent method converges to the unique solution to the differential equation so that change in condition values is minimal. The system has a solution if and only if the first iteration of steepest descent satisfies the system. The finite analogue of the descent method is applied to example problems involving finite difference equations. The well-posed problems include a singular ordinary differential equation and Laplace’s equation, each paired with respective Dirichlet-type conditions. The overdetermined problems include a first-order nonsingular ordinary differential equation with Dirichlet-type conditions and the wave equation with both Dirichlet and Neumann conditions. The method is applied in an investigation of the Tricomi equation, a long-studied equation which acts as a prototype of mixed partial differential equations and has application in transonic flow. The Tricomi equation has been studied for at least ninety years, yet necessary and sufficient conditions for existence and uniqueness of solutions on an arbitrary mixed domain remain unknown. The domains …

Most students with hearing loss attend community college, yet very little research on this population of students exists in higher education. This dissertation is one of the first to explore the experiences of mainstreamed d/Deaf students in community college. This research was conducted in order to gain a better understanding of how students who are d/Deaf interact navigate the mainstream postsecondary environment. Purposeful sampling was used to gather data from 19 individuals who attended postsecondary institutions not designed specifically for d/Deaf students. These participants were enrolled in an urban community college district in the southwestern U.S. and were receiving accommodations from their campus accessibility office. The sample included six Black females, one Black male, five Latinos, three Latinas, two White males, one White female, and two females who identified as multiracial. Data were collected through 30-60 minute semi-structured interviews in American Sign Language or spoken English, and a brief demographic survey. The interviews conducted in American Sign Language were then interpreted into English; one participant did not know ASL, and relied on oral communication. The theoretical framework of this study was Bronfenbrenner’s ecological theory. Individual development does not occur inside a vacuum; utilizing this theory allows for the analysis of …

This dissertation examines the effects of tax and expenditure limitations (TELs) stringency and its interaction with revenue diversity and the council-manager form of government on municipal general fund expenditure. TELs are explicit rules that states impose to reduce local government spending. TELs stringency varies from state to state, leading to difficulties in assessing their impact across the nation. This dissertation proposes a new means for measuring the stringency of TELs imposed on local governments. Factor analysis is utilized, and then factor scores are calculated to identify degrees of TELs stringency. This study contends that higher levels of TELs stringency are associated with lower local government spending. However, the effectiveness of TELs is dependent on revenue diversity and the form of government. This study suggests that both revenue diversity and the council-manager form of government mitigate the impacts of TELs stringency on local government spending. Panel data from 2007 to 2011 from 1,508 municipalities are utilized. This study finds that higher levels of TELs stringency are associated with lower levels of municipal general fund expenditures per capita. However, TELs stringency is effective only when revenue diversity is low and when cities have a form of government other than council-manager. These results …

Instructional communication research clearly indicates that instructor immediacy contributes significantly to effective instruction. However, the majority of immediacy studies have been conducted in traditional (face-to-face) classroom environments. More recently, instructional communication research has focused on assessing the impact of immediacy in online classroom environments. Again, immediacy appears to significantly contribute to effective instruction. The challenge is that most recent immediacy studies use immediacy measurements developed to test immediacy behaviors in face-to-face settings. Considering the lack of nonverbal communication and limited or absent synchronous or verbal communication in online instructional settings, the behaviors contributing most significantly to perceived immediacy, researchers need to reassess the immediacy construct in online environments. The present research explores and identifies behaviors reported by instructors to establish psychological closeness (i.e., immediacy) in online learning environments and assesses to what extent these behaviors are similar to or different from face-to-face immediacy-producing behaviors.

The objectives of this study were to mathematically model the quality of college life (QCL) concept and to study the associations between attachment style, emotion regulation abilities, psychological needs fulfillment and QCL via structural equation modeling. Data was collected from 507 undergraduate students (men = 178, women = 329; age M = 21.78 years, SD = 4.37). This data was used to provide evidence for the validity of the College Adjustment Scales (CAS) as a measure of quality of college life. The CAS demonstrated good convergent validity with the World Health Organization Quality of Life measure (WHOQOL), Subjective Well-being and Psychological Well-being Scales. Results: Students who were insecurely attached were as likely to feel adequate in their academic and professional endeavors as securely attached students. However, insecurely attached students had lower QCL levels, lower fulfillment of psychological needs and more emotion regulation difficulties than securely attached students. The results also indicated that Anxious Attachment and Avoidant Attachment were positively and strongly associated. Nonetheless, Anxious Attachment and Avoidant Attachment affected QCL through different mechanism. Emotion regulation mediated the path between Anxious Attachment and QCL while the fulfillment of psychological needs mediated the path between Avoidant Attachment and QCL. The fulfillment of …

Diversity impacts organizations, both internally and externally. Responses to changes in demographics come from legal and moral imperatives. As a reflection of the changes in the population demographics in the United States, universities have seen and sought increased diversity in their student enrollment. Many institutions have purposeful plans to increase representation of under-represented groups as well as those students from low-income families. Some schools also recognize the importance of having diversity represented within their staff and faculty positions as a way of creating a supportive environment that also promotes diversity of thought. As schools increase the diversity of their student population, at what level are they increasing diversity among their tenured and tenure-track faculty? The purpose of this study is to examine the impact on full-time tenured/tenure-track faculty diversity compared to enrolled student diversity at institutions that promote, require, or provide access to training for faculty search committees, including diversity/cultural awareness, legal compliance, and process training, and those institutions that do not appear to have any training requirement as documented on their websites. Only tenured/tenure-track faculty were considered as they are the permanent teaching/research positions and generally represent the core faculty of every department at a university.

The purpose of this qualitative study was to explore the association between student involvement and self-authorship among African American undergraduate students enrolled at a medium-sized, North Texas STEM-focused university. Self-identified African American undergraduate students at the university completed an online, researcher-developed survey focused on co-curricular involvement activities, degree of involvement in those activities, and perceived self-authorship indicators. From the completed survey pool (N = 49), 10 females and 5 males participated in follow-up focus group sessions. The survey data analysis was limited to descriptive statistics of student involvement and demographic data. Survey results showed that African American undergraduate students at the university were actively involved in co-curricular activities and generally satisfied with their involvement experiences. The focus groups provided a more in-depth picture of the involvement experiences showing that students believed that their commitment to co-curricular activities contributed significantly to their interpersonal and intrapersonal growth—characteristics of self-authorship. The survey and qualitative data combined suggested a positive association between the involvement of African American undergraduate students in co-curricular activities at the university and the development of self-authorship characteristics in those students. Findings from this study support the practice of intentional outreach to African American undergraduate students in order to promote their …

Zoltán Gárdonyi is described as having exemplified “the continuation of the Liszt tradition” in his music; however, since for so much of his compositional life he was forbidden to publish by the Communist government in Hungary due to his connection to the Christian church, he has been largely forgotten. Shortly after the composer’s death in 1986, Gárdonyi’s son, Zsolt (b.1946) began publishing his father’s music in addition to his own. However, the elder Gárdonyi’s works are still not widely known outside Hungary and Germany. Gárdonyi’s ability to support and reflect text musically makes his songs excellent teaching tools and recital repertoire. A characteristic example of this may be found in his Fünf Lieder nach Gedichten von Rainer Maria Rilke. According to his son, Zoltán wrote these songs “in the German romantic tradition (e.g. Brahms) like a mirror for the romantic influenced lyrics.” Examination of the Rilke-Lieder, and of the poems which make up the cycle, demonstrates the composer’s ability to “mirror” text in both general tone and specific idea. Discussion of imagery, textures and sonorities, and elements of harmony, melody and rhythm as they relate to interpretation of the poetry, reveal the depth to which the poetry is embedded in …

Security is a primary concern in this era of pervasive computing. Hardware based security mechanisms facilitate the construction of trustworthy secure systems; however, existing hardware security approaches require modifications to the micro-architecture of the processor and such changes are extremely time consuming and expensive to test and implement. Additionally, they incorporate cryptographic security mechanisms that are computationally intensive and account for excessive energy consumption, which significantly degrades the performance of the system. In this dissertation, I explore the domain of hardware based security approaches with an objective to overcome the issues that impede their usability. I have proposed viable solutions to successfully test and implement hardware security mechanisms in real world computing systems. Moreover, with an emphasis on cryptographic memory integrity verification technique and embedded systems as the target application, I have presented energy efficient architectures that considerably reduce the energy consumption of the security mechanisms, thereby improving the performance of the system. The detailed simulation results show that the average energy savings are in the range of 36% to 99% during the memory integrity verification phase, whereas the total power savings of the entire embedded processor are approximately 57%.

This study provide empirical evidence whether bias in the standard errors of Jensen’s alpha explains conflicting results in the extant literature in real estate funds. Significant alphas in real estate mutual funds and REITs are compared with heteroskedasticity consistent covariance matrix estimators (HC1, HC2 and HC3), Newey-West standard errors, a robust regression tempering the effect of high leverage points, a GARCH model, and a HC3 adjusted wild bootstrap. In the analysis of real estate mutual funds and a separate sample set of REITs, the HCCME had a minimal impact attenuating the number of firms with excess returns. Contrary to expectations the differences from HC1 to HC2 to HC3 were also negligible. The Newey-West standard error provided highly variable results when compared with the OLS results particularly in the REIT sample. Of the techniques to adjust for bias in the standard error, the wild bootstrap with HC3 adjustment to the standard error provided the most conservative result to the number of real estate mutual funds and REITs with significant alphas. The co-movement of real estate funds suggests common exogenous influences. Including state variables such as the changes in unexpected inflation, term spread, default spread, market skewness and industrial production growth in …

Consumers demand new and innovative personal computing devices every 2 years when their cellular phone service contracts are renewed. Yet, a 2 year development cycle for the concurrent development of both hardware and software is nearly impossible. As more components and features are added to the devices, maintaining this 2 year cycle with current tools will become commensurately harder. This dissertation delves into the feasibility of simplifying the development of such systems by employing heterogeneous systems on a chip in conjunction with a retargetable compiler such as the hybrid computer retargetable compiler (Hy-C). An example of a simple architecture description of sufficient detail for use with a retargetable compiler like Hy-C is provided. As a software engineer with 30 years of experience, I have witnessed numerous system failures. A plethora of software development paradigms and tools have been employed to prevent software errors, but none have been completely successful. Much discussion centers on software development in the military contracting market, as that is my background. The dissertation reviews those tools, as well as some existing retargetable compilers, in an attempt to determine how those errors occurred and how a system like Hy-C could assist in reducing future software errors. In …

Why does civil conflict spread from country to country? Existing research relies primarily on explanations of rebel mobilization tied to geographic proximity to explain this phenomenon. However, this approach is unable to explain why civil conflict appears to spread across great geographic distances, and also neglects the government’s role in conflict. To explain this phenomenon, this dissertation formulates an informational theory in which individuals contemplating rebellion against their government, or “proto-rebels,” observe the success and failure of rebels throughout the international system. In doing so, proto-rebels and governments learn whether rebellion will be fruitful, which is then manifested in the timing of rebellion and repression. The core of the dissertation is composed of three essays. The first exhorts scholars of the international spread of civil violence to directly measure proto-rebel mobilization. I show that such mobilization is associated with conflicts across the entire international system, while the escalation to actual armed conflict is associated with regional conflicts. The second chapter theorizes that proto-rebels learn from successful rebellions across the international system. This relationship applies globally, although it is attenuated by cultural and regime-type similarity. Finally, the third chapter theorizes that governments are aware of this process and engage in repression …

Conventional liquid lubricants are faced with limitations under extreme cyclic operating conditions, such as in applications that require lubrication when changing from atmospheric pressure to ultrahigh vacuum and ambient air to dry nitrogen (e.g., satellite components), and room to elevated (>500°C) temperatures (e.g., aerospace bearings). Alternatively, solid lubricant coatings can be used in conditions where synthetic liquid lubricants and greases are not applicable; however, individual solid lubricant phases usually perform best only for a limited range of operating conditions. Therefore, solid lubricants that can adequately perform over a wider range of environmental conditions are needed, especially during thermal cycling with temperatures exceeding 500°C. One potential material class investigated in this dissertation is lubricious oxides, because unlike other solid lubricant coatings they are typically thermodynamically stable in air and at elevated temperatures. While past studies have been focused on binary metal oxide coatings, such as ZnO, there have been very few ternary oxide and no reported quaternary oxide investigations. The premise behind the addition of the third and fourth refractory metals Ti and Zr is to increase the number of hard and wear resistant phases while maintaining solid lubrication with ZnO. Therefore, the major focus of this dissertation is to investigate …

We are entering an era of business intelligence and big data where simple tables and other traditional means of data display cannot deal with the vast amounts of data required to meet the decision-making needs of businesses and their clients. Graphical figures constructed with modern visualization software can convey more information than a table because there is a limit to the table size that is visually usable. Contemporary decision performance is influenced by the task domain, the user experience, and the visualizations themselves. Utilizing data visualization in task performance to aid in decision making is a complex process. We develop and test a decision-making framework to examine task performance in a visual and non-visual aided decision-making by using three experiments to test this framework. Studies 1 and 2 investigate DV formats and how complexity and design affects the proposed visual decision making framework. The studies also examine how DV formats affect task performance, as measured by accuracy and timeliness, and format preference. Additionally, these studies examine how DV formats influence the constructs in the proposed decision making framework which include information usefulness, decision confidence, cognitive load, visual aesthetics, information seeking intention, and emotion. Preliminary findings indicate that graphical DV allows …

Given unprecedented shifts in the U.S. demography marked by rapid growth in Hispanic, Asian and other ethnic market segments, marketing scholars and practitioners are confronting ways to cultivate ethnic consumers' brand preference formation, retail patronage and their ensuring consumption choices. Food is cited as a common signifier for consumers’ ethnic/cultural identity because food itself is a cultural symbol. However, little research has examined the influences of ethnic identities on consumers’ patronage behaviors of ethnic-themed restaurants. Thus, this dissertation critically explores the impact of ethnic identity and motivational factors to better understand consumers' choices of ethnic-themed restaurants with a mix-method approach. The present research investigates how ethnic identity and consumers’ need for uniqueness interplay with perceived authenticity in consumers’ patronage intention of ethnic-themed restaurants. The findings advocate the interplay among ethnic identity, consumers’ need for uniqueness, and perceived authenticity of general consumers in decision making choices of patronizing ethnic-themed restaurants. The findings have important implications for market segmentation guiding the owners of ethnic-themed restaurant the choice of environmental cues to encourage patronage intentions among general consumers. Furthermore, this study provides additional insights about motivating factors affecting decision making of patronizing ethnic-themed restaurants and contributes to the stream of research by enhancing …

Language education policy and its implementation have been controversial and ongoing issues throughout the United States, especially in the border state of Texas, with its large population of students who are learning English. This dissertation reports two studies, the first of which was a frame analysis of problems and solutions as represented by the five bills amending the Texas Education Code with regard to bilingual education and English as a second language programs. These laws, passed in 1969, 1973, 1975, 1981, and 2001, have been enacted since 1968, the year the Bilingual Education Act (BEA) was passed. The problem framed consistently by these state policy documents was inadequate instruction for children who come to school speaking languages other than English. More variability was seen in the framing of solutions, with approaches changing from the authorization of instruction in languages other than English, to the establishment of mandated bilingual programs, to the extension of special language programs, and to the establishment of dual language immersion programs. The primary ideology influencing the policy documents was the monolingual English ideology; however, alternative ideologies are apparent in the policies that allow for dual language immersion programs. Geographic information systems (GIS) analysis was used in …

Charles Baxter, in his essay “Dysfunctional Narratives: or: ‘Mistakes Were Made,’” implies that all trauma narrative is synonymous with “dysfunctional narrative,” or narrative that leaves all characters unaccountable. He writes: “In such fiction, people and events are often accused of turning the protagonist into the kind of person the protagonist is, usually an unhappy person. That’s the whole story. When blame has been assigned, the story is over.” For Baxter, trauma narrative lets everyone “off the hook,” so to speak. He would say that we write about our bitter lemonade to make excuses for our poor choices, and “audiences of fellow victims” read our tales, because their lemonade and their choices carry equal bitterness, and they require equal excuses. While trauma narrative can soothe us, as can other narrative genres, we should not dismiss trauma fiction because of a sweeping generalization. Trauma fiction also allows us to explore the missing parts of our autobiographical narratives and to explore the effects of trauma—two endeavors not fully possible without fiction. As explained in more detail later, the human mind requires narrative to formulate an identity. Trauma disrupts this process, because “trauma does not lie in the possession of the individual, to be …