Mobile applications play an important role in the dissemination of computing and information resources. They are often used in domains such as mobile banking, e-commerce, and health monitoring. Cost-effective testing techniques in these domains are critical. This dissertation contributes novel techniques for automatic construction of mobile application test suites. In particular, this work provides solutions that focus on the prohibitively large number of possible event sequences that must be sampled in GUI-based mobile applications. This work makes three major contributions: (1) an automated GUI testing tool, Autodroid, that implements a novel online approach to automatic construction of Android application test suites (2) probabilistic and combinatorial-based algorithms that systematically sample the input space of Android applications to generate test suites with GUI/context events and (3) empirical studies to evaluate the cost-effectiveness of our techniques on real-world Android applications. Our experiments show that our techniques achieve better code coverage and event coverage compared to random test generation. We demonstrate that our techniques are useful for automatic construction of Android application test suites in the absence of source code and preexisting abstract models of an Application Under Test (AUT). The insights derived from our empirical studies provide guidance to researchers and practitioners involved …

The purpose of this study was to identify the status and challenges of online distance education programs in post-secondary institutions in Ghana. This study was a replication of a similar study conducted in Kenya in 2009, at the University of Nairobi and Kenyatta University. This present study was conducted with an online survey using Google survey assessment. The survey requested responses from six post-secondary institutions in Ghana. Out of a total of 450 projected student responses, 309 responses were received with a 69% participation rate. A total of 14 responses were received for instructors out of a projected 30 resulting in 47% participation rate. And for administrators, 8 responses were received out of a projected 12 resulting in a 67% participation rate. Overall the study revealed that Ghana post-secondary institutions have established and incorporated online distance education into their programs, offering both online and blended courses. Some of these institutions established regional centers across the country and incorporated foreign instructors into their programs. The survey also revealed that students were satisfied with the overall online distance education program in their institutions which included the level of instruction, feedback and evaluation. However, there were still challenges revealed from the study that …

This thesis proposes a design of a rapidly deployable cellular network prototype that provides voice and data communications and it is interoperable with legacy devices and the existing network infrastructure. The prototype is based on software defined radio and makes use of IEEE 802.11 unlicensed wireless radio frequency (RF) band for backhaul link and an open source GSM implementation software. The prototype is also evaluated in environments where there is limited control of the radio frequency landscape, and using Voice Over Internet Protocol (VoIP) performance metrics to measure the quality of service. It is observed that in environments where the IEEE 802.11 band is not heavily utilized, a large number of calls are supported with good quality of service. However, when this band is heavily utilized only a few calls can be supported as the quality of service rapidly degrades with increasing number of calls, which is due to interference. It is concluded that in order to achieve tolerable voice quality, unused licensed spectrum is needed for backhaul communication between base stations.

As part of an effort to understand psychological consequences among family members of patients sustaining a traumatic injury, medical research has turned to the role of resilience – or the ability to bounce back from and maintain psychological well-being in the wake of an adverse event— in mitigating the potential distress (i.e., depression and burden) of caregiving (Bonanno, 2004; Roberson et al., under review). This study sought to examine the ability for trait-resilience to predict trajectories of distress over the course of a year among 124 family members and loved ones of patients admitted to a Level I Trauma Center. A cross-lagged path model examining resilience, burden, and depression at baseline, 3, 6, and 12 months after injury showed that, while depression strongly predicted later burden, resilience was not a significant predictor of either outcome in the model. When depression and burden were subjected to a person-centered analysis (i.e., latent growth curve analysis), two major classes were identified: caregivers with high, chronic distress (33% of the sample) and low-moderate distress that declined over time. A three-class solution for caregiver burden further identified a moderate, increasing trajectory class. Predictive discriminant analyses revealed that trait-resilience was a major differentiating trait between class …

Elevated social anxiety (SA) is linked to issues with emotional distress, substance use, and social anxiety disorder (SAD). Notwithstanding concerns of how sexuality has been defined in the extant literature, emerging evidence suggests that the prevalence of SA and related challenges may be disproportionately present among sexual minorities, including lesbians, gay men, and bisexuals (LGBs). This trend may be especially relevant within the developmental context of emerging adulthood, an important period for development of sexual identity, and a time when individuals are already predisposed to heightened feelings of SA. The present study examined the relationship between sexual orientation (measured using sexual identity, sexual attraction, and past romantic and sexual behavior) and social anxiety (related to social interaction and social performance) among emerging adults. minority sexual identities [Welch's F(5,48.08) = 5.56, p = .002, ηp2 = .02.], same-sex attraction [Welch's F(4,108.06) = 11.27, p < .001, ηp2 = .04], and same-sex romantic [Welch's F(5,85.91) = 6.88, p < .001, ηp2 = .03] and sexual experiences[F(5,61.95) = 8.88, p < .001, ηp2 = .04], particularly among those who indicated attraction to multiple sexes. Findings support research that indicates that sexual minority adults experience higher levels of SA than majority (i.e., heterosexual, opposite-sex …

Corrosion represents the single most frequent cause for product replacement or loss of product functionality with a 5% coat to the industrial revenue generation of any country in this dissertation the efficacy of using filled coatings as a protection coating are investigated. Fillers disrupt the polymer-substrate coating interfacial area and lead to poor adhesion. Conflicting benefits of increasing surface hardness and corrosion with long term durability through loss of adhesion to the substrate are investigated. The effects of filler type, filler concentration and exposure to harsh environments such as supercritical carbon dioxide on salt water corrosion are systematically investigated. The constants maintained in the design of experiments were the substrate, AISI-SAE 1018 steel substrate, and the corrosive fluid synthetic sea salt solution (4.2 wt%) and the polymer, Bismaleimide (BMI). Adhesion strength through pull-off, lap shear and shear peel tests were determined. Corrosion using Tafel plots and electrochemical impedance spectroscopy was conducted. Vickers hardness was used to determine mechanical strength of the coatings. SEM and optical microscopy were used to examine dispersion and coating integrity. A comparison of fillers such as alumina, silica, hexagonal boron nitride, and organophilic montmorillonite clay (OMMT) at different concentrations revealed OMMT to be most effective with …

High entropy alloys (HEAs) are alloys with five or more principal elements. Due to these distinct concept of alloying, the HEA exhibits unique and superior properties. The outstanding properties of HEA includes higher strength/hardness, superior wear resistance, high temperature stability, higher fatigue life, good corrosion and oxidation resistance. Such characteristics of HEA has been significant interest leading to researches on these emerging field. Even though many works are done to understand the characteristic of these HEAs, very few works are made on how the HEAs can be applied for commercial uses. This work discusses the application of High entropy alloys in biomedical applications. The coronary heart disease, the leading cause of death in the United States kills more than 350,000 persons/year and it costs $108.9 billion for the nation each year in spite of significant advancements in medical care and public awareness. A cardiovascular disease affects heart or blood vessels (arteries, veins and capillaries) or both by blocking the blood flow. As a surgical interventions, stent implants are deployed to cure or ameliorate the disease. However, the high failure rate of stents has lead researchers to give special attention towards analyzing stent structure, materials and characteristics. Many works related to …

This dissertation examines a university faculty (n = 41) and diverse students (n = 93) including students with disability (n = 44), students without disability (n = 21), and international students (n = 28) regarding their attitudes toward and actions associated with inclusive instruction based on the universal design for learning (UDL) principles and practices. Two online surveys, the Inclusive Teaching Strategies Inventory (ITSI) and the Inclusive Teaching Strategies Inventory-Student (ITSI-S), were administered at a large, public Southwest university (N = 134). The ITSI and ITSI-S contain seven subscales representing the following constructs: (a) accommodations, (b) accessible course materials, (c) course modifications, (d) inclusive lecture strategies, (e) inclusive classroom, (f) inclusive assessment, and (g) disability laws and concepts. A series of multivariate analyses of variances (MANOVAs) measured the overall of attitude subscales and overall action subscales, and an independent-samples test (t-test) compared mean scores on the seven Attitude subscales and seven Action subscales to identify predictors of these attitudes and actions among faculty and students. The main findings were (a) significant differences among diverse students, where students with disability responded negatively on the Action subscales and (b) significant differences between faculty and diverse students where international students had a positive …

Promising results from the use of problem-based learning (PBL) as a teaching method in medical programs have encouraged many institutions to incorporate PBL into their curricula. This study investigates how applying hybrid-PBL (H-PBL) in a microbiology laboratory impacts students' higher-order thinking as compared to applying a lecture-based pedagogy. The experimental design compared the learning outcomes of two groups of students: the control group and the H-PBL group, for whom PBL cases comprised 30% of the curriculum. Both groups were taught basic skills for the microbiology lab by the same instructor. Using the traditional teaching style for the control group, the instructor offered each student what they needed for their experiments. The H-PBL group practiced experimental design, data analysis, theory proposal, and created research questions by using six study cases that were closely linked to the area of study. The outcome was measured using a pre- and post- assessment consisting of 24 questions that was designed by following Bloom's taxonomy of learning levels. A one-way ANOVA was used to analyze the data. The results showed that for the first three levels of Bloom's taxonomy— knowledge, comprehension, and application—there were no statistically significant differences between the H-PBL and control group gain scores …

Mobile wireless sensor networks are not widely implemented in the real world, even after years of research carried out in this field. One reason is the lack of understanding of the impact that mobility has on network performance. The simulation and emulation of mobile wireless sensor networks is necessary before they are deployed for the real-world applications. This thesis presents a simulation-based study of different mobility models. The total area coverage that depends on the pattern of node movements is observed through simulations. The spatial distribution of node locations is also studied. Various synthetic mobility models available are explored based on their theoretical descriptions. ‘BonnMotion' is used as the network simulator for investigating different mobility scenarios. The results obtained after simulations are imported to MATLAB and the analysis of node movements is done through various plots and inferences from the data. The comparison of mobility models is also discussed based on their spatial node distribution in the simulated scenarios.

Spaces such as the closed interval [0, 1] do not have the property of being homogeneous, strongly locally homogeneous (SLH) or countable dense homogeneous (CDH), but the Hilbert cube has all three properties. We investigate subsets X of real numbers to determine when their countable product is homogeneous, SLH, or CDH. We give necessary and sufficient conditions for the product to be homogeneous. We also prove that the product is SLH if and only if X is zero-dimensional or an interval. And finally we show that for a Borel subset X of real numbers the product is CDH iff X is a G-delta zero-dimensional set or an interval.

This study applied the stages of transformative learning to faculty perceptions and application of best practices to online learning. Research questions included: Can transformative learning theory constructs be used to identify potential barriers in faculty development and delivery of online instruction?; How does the stage of transformative learning of online faculty relate to their perceptions about online learning and their application of best practices?; Is there a correlation between stage of transformative learning and the amount of experience with online instruction a faculty member has? Principal component analysis and cluster analysis support a four-component solution. The four constructs equate to Mezirow's four stages of learning: transforming frames of reference through critical reflection of assumptions, validating contested beliefs through discourse, taking action on one's reflective insight, and critically assessing it. Multiple regression analyses were run to predict faculty perceptions on the identified components. Three of these were statistically significant based on years of experience teaching online, the number of professional development workshops taken on online teaching, or both. While the instrument appears to be a valid measurement of transformation of frame of reference, examination of previously contested beliefs, and critical assessment of action, further efforts will be needed before this is …

Plant microtubules play essential roles in cell processes such as cell division, cell elongation, and organelle organization. Microtubules are arranged in highly dynamic and ordered arrays, but unlike animal cells, plant cells lack centrosomes. Therefore, microtubule nucleation and organization are governed by microtubule-associated proteins, including a microtubule-severing protein, katanin. Mutant analysis and in vitro characterization has shown that the highly conserved katanin is needed for the organization of the microtubule arrays in Arabidopsis and rice as well as in a variety of animal models. Katanin is a protein complex that is part of the AAA+ family of ATPases. Katanin is composed of two subunits, katanin-p60, a catalytic subunit and katanin-p80, a regulatory subunit. Spastin is another MT-severing protein that was identified on the basis of its homology to katanin. In animal cells, spastin is also needed for microtubule organization, but its functionality has not yet been investigated in plants. To initiate an exploration of the function of katanin-p60 and spastin in Zea mays, my research goal was to generate tools for the expression and purification of maize katanin-p60 and spastin proteins in vitro. Plasmids that express katanin-p60 and spastin with N-terminal GST tags were designed and constructed via In-Fusion® cloning …

This study examines the ways visual culture influences a child's drawings. The child is my 9-year-old daughter Nada, who was born in Saudi Arabia and is a fourth-grade student temporarily living in the United States. The study uses qualitative methods of data collection and exploratory case study research design as a methodology. The data were analyzed in light of Althusser's theory of ideology, specifically the notion of interpellation, along with visual culture theories. In addition, gender performativity theory, specifically the work of Judith Butler, was used to consider gender issues when these concerns emerged from the study. Nada has been exposed to two diverse cultures, those of Saudi Arabia and the United States. Both cultures may impact Nada's interpretations of her visual surroundings in various ways. Therefore, recognizing and examining how she interacts with US visual culture might help to uncover how such interactions constitute the basis of her perceptions, identities, and critical thinking. Drawing is not only a means of self-expression but also an important function of communication, identity formation, and represents possible ways of being in the world that are related to culture, community, and society as a whole. The study begins with the premise that there is …

The objective of this research was to investigate the performance of two-phase spray cooling with HFC-134a and HFO-1234yf refrigerants using practical enhanced heat transfer surfaces. Results of the study were expected to provide a quantitative spray cooling performance comparison with working fluids representing the current and next-generation mobile air conditioning refrigerants, and demonstrate the feasibility of this approach as an alternative active cooling technology for the thermal management of high heat flux power electronics (i.e., IGBTs) in electric-drive vehicles. Potential benefits of two-phase spray cooling include achieving more efficient and reliable operation, as well as compact and lightweight system design that would lead to cost reduction. The experimental work involved testing of four different enhanced boiling surfaces in comparison to a plain reference surface, using a commercial pressure-atomizing spray nozzle at a range of liquid flow rates for each refrigerant to determine the spray cooling performance with respect to heat transfer coefficient (HTC) and critical heat flux (CHF). The heater surfaces were prepared using dual-stage electroplating, brush coating, sanding, and particle blasting, all featuring "practical" room temperature processes that do not require specialized equipment. Based on the obtained results, HFC-134a provided a better heat transfer performance through higher HTC and …

In game based learning, motivating the players to learn by providing them a desirable gameplay experience is extremely important. However, it's not an easy task considering the quality of today's commercial non-educational games. Throughout the gameplay, the player should neither get overwhelmed nor under-challenged. The best way to do so is to monitor the player's actions in the game because these actions can tell the reason behind the player's performance. They can also tell about the player's lacking competencies or knowledge. Based on this information, in-game educational interventions in the form of hints can be provided to the player. The success of such games depends on their interactivity, motivational outlook and thus player retention. UNTANGLED is an online mapping game based on crowd-sourcing, developed by Reconfigurable Computing Lab, UNT for the mapping problem of CGRAs. It is also an educational game for teaching the concepts of reconfigurable computing. This thesis performs qualitative comparative analysis on gameplays of low performing players of UNTANGLED. And the implications of this analysis are used to provide recommendations for improving the gameplay experience for these players by guiding them. The recommendations include strategies to reach a high score and a compact solution, hints in the …

Institutional repositories have been introduced as an innovative and alternative technology for scholarly communication and have received considerable attention from scholars across disciplines and around the globe. While some universities in Thailand have developed and implemented institutional repositories for nearly a decade, knowledge of the acceptance and use of institutional repositories on the individual level in the country remains limited. As an insufficient knowledge of technology acceptance and adoption at the individual level is considered partially responsible for the underutilization of innovation or of information system implementation, this study seeks to uncover knowledge regarding the level of institutional repository acceptance and use. This study applied the unified theory of acceptance and use of technology (UTAUT) model and the model of faculty members' self-archiving behavior to investigate factors affecting faculty acceptance and use of university-based institutional repositories. The study employed a mixed methods approach involving a survey followed by semi-structured, one-to-one interview. This study confirms that the success of university-based institutional repositories depends not on a single factor but on multiple factors. The results of the study show that performance expectancy, social influence, and resistance to change were direct determinants of faculty members' intention to use institutional repositories. Additionally, behavioral intention …

This manuscript is a study of the Thirty-Third Infantry, United States Volunteers, a regiment that was recruited in Texas, the South, and the Midwest and was trained by officers experienced from the Indian Wars and the Spanish-American War. This regiment served as a front-line infantry unit and then as a constabulary force during the Philippine War from 1899 until 1901. While famous in the United States as a highly effective infantry regiment during the Philippine War, the unit's fame and the lessons that it offered American war planners faded in time and were overlooked in favor of conventional fighting. In addition, the experiences of the men of the regiment belie the argument that the Philippine War was a brutal and racist imperial conflict akin to later interventions such as the Vietnam War. An examination of the Thirty-Third Infantry thus provides valuable context into a war not often studied in the United States and serves as a successful example of a counterinsurgency.

Natural fibers like kenaf, hemp, flax and sisal fiber are becoming alternatives to conventional petroleum fibers for many applications. One such applications is the use of Non-woven bio-fiber mats in the automobile and construction industries. Non-woven hemp fiber mats were used to manufacture plywood in order to optimize the plywood structure. Hemp fiber mats possess strong mechanical properties that comparable to synthetic fibers which include tensile strength and tensile modulus. This study focuses on the use of hemp fiber mat as a core layer in plywood sandwich composite. The optimization of fiber mat plywood was done by performing a three factor experiment. The three factors selected for this experiment were number of hemp mat layers in the core, mat treatment of the hemp mat, and the glue content in the core. From the analysis of all treatments it was determined that single hemp mat had the highest effect on improving the properties of the plywood structure.

Renewable power systems are becoming more affordable and provide better options than fossil-fuel generation, for not only the environment, but a benefit of a reduced cost of operation. Methods to optimize charging batteries from renewable technologies is an important subject for off-grid and micro-grids, and is becoming more relevant for larger installations. Overcharging or undercharging the battery can result in failure and reduction of battery life. The Arduino hybrid MPPT controller takes the advantage of solar and wind energy sources by controlling two systems simultaneously. The ability to manage two systems with one controller is better for an overall production of energy, cost, and manageability, at a minor expense of efficiency. The hybrid MPPT uses two synchronous buck DC-DC converters to control both wind and solar. The hybrid MPPT performed at a maximum of 93.6% efficiency, while the individual controller operated at a maximum 97.1% efficiency when working on the bench test. When designing the controller to manage power production from a larger generator, the inductor size was too large due to the frequency provided by the Arduino. A larger inductor means less allowable current to flow before the inductor becomes over saturated, reducing the efficiency of the controller. Utilizing …

This study analyzes corporate governance practices of foreign (non-U.S.) issuers listed on the New York Stock Exchange (NYSE) and Nasdaq. Specifically, I examine the extent to which these foreign issuers voluntarily comply with U.S. stock exchange corporate governance requirements applicable to domestic issuers. My sample consists of 201 foreign companies primarily domiciled in Brazil, China, Israel, and the United Kingdom. I find that 151 (75 per cent) of the sample firms do not elect to comply with any of the U.S. corporate governance requirements. Logistic regression analysis generally supports the hypotheses that conformance with U.S. GAAP and percentage of managerial ownership are positively associated, and that percentage ownership by major shareholders is negatively associated with foreign firms electing to comply with U.S. corporate governance rules. This evidence is relevant for regulators and investors.

A gap exists in education research in the area of district support for campus-based professional learning communities (PLCs). The current study was an examination of practitioner perceptions of district structures and practices that support the development and sustainability of PLCs in public high schools. I examined the perceptions of 341 teachers, campus administrators, and district administrators in a suburban North Texas public school district with three comprehensive high schools. Using a sequential mixed-method design, quantitative data from an electronic survey and qualitative data from face-to-face interviews were collected and analyzed. The findings revealed a generally positive view of central office support among the participants, including consistent ratings from each high school, each campus-level position, each content area, and each level of experience in the district. There was some misalignment of perceptions between campus-level and district-level staff. The study also uncovered a set of best and worst district practices, the six PLC strengtheners and six PLC inhibitors, which were synthesized into a set of recommendations and guidelines for district support for high school PLCs. From participant feedback, I concluded district support is needed and desired by high school practitioners and there are specific district practices and structures that are most effective. …

This exploratory research focuses on identifying the roles and perspectives of community gardens in the Dallas area. Results from semi-structured interviews reveal the social and political makeup of the neighborhoods where the garden projects in this study are located. While these findings highlight the benefits of gardening in the city, they can also be contested spaces. In advocating for the proliferation of garden projects in the city, community organizations would benefit from understanding the nuances of garden initiatives and the way in which they are perceived by members of the garden, nearby residents, and policy makers.

In this study, the surface degradation behavior was studied for typical examples from bulk metallic glasses (BMGs), metallic glass composites (MGCs) and high entropy alloys (HEAs) alloy systems that are of scientific and commercial interest. The corrosion and wear behavior of two Zr-based bulk metallic glasses, Zr41.2Cu12.5Ni10Ti13.8Be22.5 and Zr57Cu15.4Ni12.6Al10Nb5, were evaluated in as-cast and thermally relaxed states. Significant improvement in corrosion rate, wear behavior, and friction coefficient was seen for both the alloys after thermal relaxation. Fully amorphous structure was retained with thermal relaxation below the glass transition temperature. This improvement in surface properties was explained by annihilation of free volume, the atomic scale defects in amorphous metals resulting from kinetic freezing. Recently developed MGCs, with in situ crystalline ductile phase, demonstrate a combination of mechanical properties and fracture behavior unseen in known structural metals. The composites showed higher wear rates but lower coefficient of friction compared to monolithic amorphous glasses. No tribolayer formation was seen for the composites in sharp contrast to that of the monolithic metallic glasses. Corrosion was evaluated by open circuit potential (OCP) analysis and potentiodynamic polarization. Site-specific corrosion behavior was studied by scanning vibration electrode technique (SVET) to identify formation of galvanic couples. Scanning kelvin …