The attitude (or orientation) of an object is often crucial in its ability to perform a task, whether the task is driving a car, flying an aircraft, or focusing a satellite. In traditional control approaches, the attitude is often parameterized by Euler angles or unit quaternions which exhibit problems such as gimbal lock or ambiguity in representation, respectively. These complications prevent the controllers from achieving global stability and worse they may cause real physical harm due to unexpected large motions. More recent works have achieved global stability and avoided these system failures by working directly on the configuration manifold, but these approaches are generally complex or lack automatic, user-friendly ways to tune them. The goal of this dissertation is to develop simple geometric attitude controllers that are globally, exponentially stable and can be automatically tuned. By simple, we mean that the controllers are computationally efficient for real time implementation on embedded computers and the tuning parameters have geometric interpretations. These properties make the controllers user friendly and practical for real hardware implementation even on fast dynamical systems. Furthermore, we aim to obtain an automatic tuning procedure that ensures convergence, and can also quantify and optimize performance guarantees. We achieve our goal through four major contributions. The first is a substantial generalization on the theory of classical Riemannian metrics for tangent bundles which provides the ability to compare and combine attitude and velocity terms in the stability analysis, allowing us to consider a larger set of feasible controller gains. The second contribution is a framework to study the stability of attitude systems on manifolds and to automatically tune the controller gains by combining Riemannian geometry, contraction theory, and offline optimization. The third contribution is the development of a globally, exponentially stable attitude controller. This controller overcomes the topological limitation that prevents continuous, time-invariant controllers from achieving global stability by using a time-varying intermediate reference trajectory. The fourth contribution is the improvement of the proposed controllers by way of point-wise-in-time quadratic programming.

For the same reasons which prompted its ratification in 1990 as the Global Stratotype Section and Point for the Mid-Carboniferous boundary, namely, section completeness, abundant fossils, and excellent exposure, the Morrowan Arrow Canyon Bird Spring strata is recommended as a candidate standard sequence stratigraphic reference for the Morrowan portion of the Lower Absaroka I supersequence. The stratigraphic architecture of Morrowan strata in Arrow Canyon was largely controlled by high-amplitude (100-m), high-frequency sea-level changes. Outcrop data and facies stacking patterns define 59 fifth-order fundamental cycles. These fundamental cycles stack into ten third-order sequences with an average duration of 320 ka. Changes in both cycle thickness and fundamental cycle type indicate that the second-order sea-level curve of Golonka and Keissling for the Lower Absaroka Ia supersequence should be modified to reflect rising sea-level from the Mid-Carboniferous boundary with maximum flooding conditions ~120 to 135 meters above the Mid-Carboniferous boundary, followed by falling sea-level to ~6 meters below the Morrowan-Atokan boundary in Arrow Canyon. Additionally, cycle diagnostic conodonts and foraminifera permit correlation of selected third-order sequences to basins containing time-equivalent strata.

In this thesis, formulas for the local tangent stiffness matrix of a plane frame member are derived by differentiating the member resistance vector in the displaced position. This approach facilitates an analysis using only one element per member. The formulas are checked by finite difference. The derivation leads to the familiar elastic and geometric stiffness matrices used by other authors plus an additional higher order geometric stiffness matrix. Contributions of each of the three sub-matrices to the tangent stiffness matrix are studied on both the member and structure levels through two numerical examples. These same examples are analyzed three different ways for comparison. First, the examples are analyzed using the method presented in this thesis. Second, they are analyzed with the finite element modeling software ABAQUS/CAE using only one element per member. Third, they are analyzed with ABAQUS using 200 elements per member. Comparisons are made assuming the ABAQUS analysis which uses 200 elements per member is the most accurate. The element presented in this thesis performs much better than the ABAQUS analysis which uses one element per member, with maximum errors of 1.0% and 40.8% respectively, for a cantilever column example. The maximum error for the two story frame example using the ABAQUS analysis with one element per member is 42.8%, while the results from the analysis using the element presented in this thesis are within 1.5%. Using the element presented in this thesis with only one element per member gives good and computationally efficient results for second-order analysis.

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Alpha-ketoglutaric acid (AKGA) is an organic acid important for the metabolism of essential amino acids as well as for the transfer of cellular energy. It is a precursor of glutamic acid which is produced by the human body during the Krebs Cycle. AKGA has a specific industrial interest as it can be taken as a dietary supplement and is also widely used as a building block in chemical synthesis. Collectively termed as hydrazine (HZs), hydrazine (HZ) and monomethylhydrazine (MMH) are hypergolic fuels that do not need an ignition source to burn. Because of the particular HZs' characteristics the National Aeronautics and Space Administration (NASA) at Kennedy Space Center (KSC) and the US Air Force at Cape Canaveral Air Force Station (CCAFS) consistently use HZ and MMH as hypergolic propellants. These propellants are highly reactive and toxic, and have carcinogenic properties. The handling, transport, and disposal of HZ waste are strictly regulated under the Resource Conservation and Recovery Act (RCRA) to protect human health and the environment. Significant quantities of wastewater containing residuals of HZ and MMH are generated at KSC and CCAFS that are subsequently disposed off-site as hazardous waste. This hazardous waste is shipped for disposal over public highways, which presents a potential threat to the public and the environment in the event of an accidental discharge in transit. NASA became aware of research done using AKGA to neutralize HZ waste. This research indicated that AKGA transformed HZ in an irreversible reaction potentially leading to the disposal of the hypergols via the wastewater treatment facility located at CCAFS eliminating the need to transport most of the HZ waste off-site. New Mexico Highlands University (NMHU) has researched this transformation of HZ by reaction with AKGA to form stabilized pyridazine derivatives. NMHU's research suggests that the treatment of HZ and MMH using AKGA is an irreversible reaction; once the reaction takes place, HZ and/or MMH cannot re-form from the byproducts obtained. However, further knowledge relating to the ultimate end products of the reaction, and their effects on human health and the environment, must still be addressed. The known byproduct of the AKGA/HZ neutralization reaction is 6-oxo-1,4,5,6-tetrahydro-pyridazine-3-carboxylic acid (PCA), and the byproduct of the AKGA/MMH reaction is 1-methyl-6-oxo-4,5-dihydro-pyridazine-3-carboxylic acid (mPCA). This research addressed several primary areas of interest to further the potential use of AKGA for HZ and MMH neutralization: 1) isolation of the end-product of the MMH-AKGA degradation process, 1-methyl-6-oxo-4,5-dihydro-pyridazine-3-carboxylic acid (mPCA), and determination of several physical properties of this substance, 2) evaluation of the kinetics of the reaction of AKGA with HZ or MMH, 3) verification of the chemical mechanism for the reaction of the individual hypergols with AKGA, 4) determination of whether the addition of a silicone-based antifoaming agent (AF), citric acid (CA) and/or isopropyl alcohol (IPA) to the AKGA and HZ or MMH solution interferes with the degradation reaction, 4) application of laboratory bench scale experiments in field samples, and 5) determination of the reaction enthalpy of these reactions.

The purpose of this study was to determine the perceptions of 244 school- and district-based administrators who were employed in a Florida school district from 2003- 2011 regarding superintendent second-order change leadership decisions and events to achieve equity and access to excellence for all students in the school district. Interviews were also conducted with 11 active and retired school-based and district-based administrators to specifically address any factors that led to equity and access to excellence as well as any challenges the school district faced when implementing those actions and decisions. Quantitative data were used for a historical comparison of the targeted school district prior to and after 2003 to further understand the impact of equity and access to excellence within the school district. Two superintendent decisions were believed to be extremely educationally significant by respondents: High school reading centerpiece and International Baccalaureate program launch at Seminole High School. Respondents were least familiar with Central Florida Public School Boards Coalition established and Established Principal Forum. Three events were largely believed to be extremely educationally significant by respondents: District rated A each year of accountability, District designated academically high- performing, and Unitary status achieved. Respondents were least familiar with Florida Center for Reading Research project in high schools and Superintendent Leadership transition. iv Responses to open-ended questions indicated that equity and access to excellence were achieved in the school district between 2003 to 2011. The decision to attain unitary status led to other actions and decisions to achieve equity and access to excellence, e.g., the creation of magnet schools, the introduction of open access to Advanced Placement courses. The superintendent’s greatest challenge was perceived by respondents as lack of funding. Interviewees cited poverty as a limiting factor in achievement of equity and excellence. All respondents agreed that working with the lowest achieving 25% of students to improve performance on the Florida Comprehensive Achievement Test was key to achieving equity and excellence in the school district. Most of the interviewees believed that all students have access to equity and excellence. In offering advice to other districts, most of the interviewees stressed the importance of focusing on data, demographics, and academic programs, stating that leaders should be committed to achieving equity and excellence and there needs to be total buy-in from the whole district. Further, superintendent success depended on a clear focus, a set of core values and the willingness and courage to implement second-order change.

Since 1970, high project failure rate and low user satisfaction has elicited research on users and their role in the process. It is believed that users' physical participation or psychological involvement in the development process can improve user satisfaction and/or system quality. Previous research treats users as a source of requirements and hypothesizes satisfaction to increase when requirements are fulfilled. However, inconsistent conclusions lead to confusion. Recently, a co-production concept has been proposed to understand consumer participation in product development process. In this reconceptualization, users, instead of requirement generator, should be part of the production. In this study, based on co-production concept, we view users as one knowledge source and study how knowledge can be coordinated through the co-production process. After collecting data from 97 system users, most of the hypothesized relationships have been confirmed. IS-user co-production has a positive effect on expertise coordination and, in turn, improves teamwork outcomes. The only relationship that is not significant is between "bring expertise to bear" and "creativity." Implications for practitioner and suggestion for future research are provided. Co-production was found to be a second-order construct comprised of multiple formative constructs. Higher levels of coproduction behavior were expected and were found to produce better outcomes of collaborative efforts. For future study, this relationship is expected to hold true when pairs of information systems developers and information systems users who have worked together on the same information systems development project are surveyed at the end of their projects (or just before it ends or recently thereafter).

Leading through change is a difficult process. School leaders who hope to create meaningful, long-term change must be cognizant of numerous factors. This study was undertaken with the hope of increasing educational leaders' awareness of how their decisions are viewed by those who follow them. Case studies revealed pertinent data within two schools that have undertaken a significant change initiative. All 2007 and 2008 Small Learning Communities (SLC) grant-recipient schools in Florida were invited to participate in a series of case studies. Participating principals were questioned about their perceptions of how they fulfill their change leadership role related to the seven factor of second-order change, as identified by Marzano, Waters, and McNulty (2005). Teachers were questioned about their perceptions of the principal's performance in leading the new initiative by the same seven factors. Principal and teacher scores were then compared for each school to identify potential differences in perceptions related change implementation and the seven factors. Although the data cannot be generalized, statistical analyses did reveal significant differences in perceptions of between principals and teachers in each of the two participating schools. In Study 1, these differences existed in Knowledge of Curriculum, Instruction, and Assessment; Optimizer; Flexibility; and Ideals/Beliefs. In Study 2, differences were identified in the same areas as in Study 1, but in Intellectual Stimulation and Monitoring/Evaluating as well. Differences in teacher perceptions across the schools were identified in Knowledge of Curriculum, Instruction, and Assessment; and in Intellectual Stimulation.

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Our goal in this thesis is to study the dynamics of the classical predator-prey model and the predator-prey model in the chemostat when a discrete delay is introduced to model the time between the capture of the prey and its conversion to biomass. In both models we use Holling type I response functions so that no oscillatory behavior is possible in the associated system when there is no delay. In both models, we prove that as the parameter modelling the delay is varied Hopf bifurcation can occur. However, we show that there seem to be differences in the possible sequences of bifurcations. Numerical simulations demonstrate that in the classical predator-prey model period doubling bifurcation can occur, possibly leading to chaos while that is not observed in the chemostat model for the parameters we use. For a delay differential equation, a prerequisite for Hopf bifurcation is the existence of a pair of pure imaginary eigenvalues for the characteristic equation associated with the linerization of the system. In this case, the characteristic equation is a transcendental equation with delay dependent coefficients. For our models, we develop two different methods to show how to find values of the bifurcation parameter at which pure imaginary eigenvalues occur. The method used for the classical predator-prey model was developed first. However, it was necessary to develop a more robust, less complicated method to analyze the predator-prey model in the chemostat with a discrete delay. The latter method was then generalized so that it could be applied to any second order transcendental equation with delay dependent coefficients. / Thesis / Doctor of Philosophy (PhD)