Digital Commons Network^™

Transport, Species-Specific Resource Competition, And Shallow Water Effects In Coupled Bio-Physical Ecosystem Models For C. Polykrikoides Harmful Algal Blooms Off The Coast Of Korea, Jang-Geun Choi

Doctoral Dissertations

This thesis examines the role of transport and environmental variables in determining the occurrence or suppression of harmful algal blooms (HABs). In the first part, a simple 2-D diagnostic model is used to hindcast HABs occurring off the coast of Korea using observations of averaged environmental factors including nutrient concentration. Hindcasting results using the model show that physical transport of HABs is of the same order of importance as the environmental conditions in controlling HABs. The model reproduces the interannual variability of the observe HABs off the coast of Korea. The relative importance of the environmental factors based on limiting …

On The Images Of Braid Group Representations Coming From Braided Fusion Categories, Jason Allen Green

Doctoral Dissertations

Braided fusion categories are algebraic structures with strong ties to the representation theory of finite groups, Hopf algebras, and quantum groups. These structures also have strong connections with braid groups and low-dimensional topology. Recently, braid group representations coming from braided fusion categories have become a topic of interest in areas of condensed matter physics and topological quantum computation. Particularly interesting are the properties of the images of these representations.

Calculations to determine the finiteness of these images have been performed for a few cases. A class of braided fusion categories coming from finite groups (group-theoretical) has been shown to yield …

Path Components And Elementary Orbits Of Um(2,R), Timothy A. Fill

Doctoral Dissertations

For any commutative ring R with identity, Um(2, R) is the set of all vectors α ∈ R^2 such that α^T β = 1 for some β ∈ R^2. Motivated by Hinson and Samuel, we endow Um(2, R) with a pseudo-graph structure and introduce a family of functions on the general ring R defined in terms of graph theoretic distance from a designated base-point or base-set. We propose a particular connected base-set whose quasi-Euclidean function exhibits the most computationally convenient properties. Unlike in Um(n, R), n ≥ 3, the relationship between path components of Um(2, R) and its orbits under …

Merging Ecology And Earth System Modeling: Biotic And Abiotic Controls Drive Soil Carbon And Nitrogen Cycling In Microbial-Explicit Soil Biogeochemistry Models, Emily Kyker-Snowman

Doctoral Dissertations

Ecological processes drive terrestrial biogeochemistry, yet the incorporation of ecology into the Earth system models that we use to understand and project global change remains. My dissertation focuses on expediting the incorporation of ecology into Earth system models, first by laying out a roadmap from initial assessment of ecological insights to eventual ESM incorporation, and then by demonstrating this roadmap using the example of microbially- controlled carbon and nitrogen cycling in soil. The paradigm around SOM formation and loss has shifted in recent decades away from a focus on the chemically recalcitrant leftovers of litter decomposition and towards a paradigm …

Balancing Fracture And Fatigue Performance In Asphalt Pavements: A Hybrid Mechanistic And Statistical Modelling Approach, Danial Mirzaiyanrajeh

Doctoral Dissertations

The asphalt mix design and evaluation approaches are divided into two main categories as empirical and mechanistic-empirical (M-E) methods. The empirical methods are based on empirical observations of in-service pavement performance, and they do not take into account engineering properties or failure criteria. The M-E methods were introduced as a new generation for design and evaluation approaches that consider fundamental mixture properties such as material stiffness to determine the pavement's structural response. However, the need for expensive and time-consuming performance-based laboratory tests and local calibration makes the M-E methods unsuitable for routing design. In addition, during the last few years, …

Economics Of Pest Control And Pollination Conservation: Perspectives From A Bioeconomic Model And A Choice Experiment, Linghui Wu

Doctoral Dissertations

The first chapter focuses on the need to reduce pollinator exposure to harmful pesticides has led to calls to expedite theadoption of integrated pest management (IPM). We make the case that IPM is not explicitly 'pollinator friendly', but rather must be adapted to reduce impacts on pollinators and to facilitate synergies between crop pollination and pest control practices and ecosystem services. To reconcile these diverse needs, we introduce a systematic framework for 'integrated pest and pollinator management' (IPPM). We also highlight novel tools to unify monitoring and economic decision-making processes for IPPM and outline key policy actions and knowledge gaps. …

Learning To Act With Robustness, Reazul Hasan Russel

Doctoral Dissertations

Reinforcement Learning (RL) is learning to act in different situations to maximize a numerical reward signal. The most common approach of formalizing RL is to use the frameworkof optimal control in an inadequately known Markov Decision Process (MDP). Traditional approaches toward solving RL problems build on two common assumptions: i) exploration is allowed for the purpose of learning the MDP model and ii) optimizing for the expected objective is sufficient. These assumptions comfortably hold for many simulated domains like games (e.g. Atari, Go), but are not sufficient for many real-world problems. Consider for example the domain of precision medicine for …

Stigma And Social-Emotional Health In Youth With Learning Differences, Kelsey Maki

Doctoral Dissertations

Youth diagnosed with specific learning disorder (SLD) and/or attention deficit hyperactivity disorder (ADHD), defined collectively for the purposes of this study as youth with learning differences, experience poorer social-emotional health outcomes in comparison to their typically developing peers. These youth additionally experience stigma from their peers, teachers, and broader community, which may impact social-emotional health. As a secondary data analysis of a larger study, the present study investigated the role of stigma consciousness alongside demographic variables, self-esteem, and peer relationships in social-emotional health outcomes. Due to the possible differences between youth diagnosed with SLD, ADHD, and comorbid SLD/ADHD, group differences …

Perceived Organizational Justice And Trust As Mediators Between Perceived Gender Discrimination And Organizational Outcomes, Qin Cai

Doctoral Dissertations

Many people, especially women, have experienced gender discrimination in their work lives (e.g., Eagly & Diekman, 2005; Morrison et al., 1987). Gaining an understanding of how perception of gender discrimination is related to organizational outcomes is very important for organizations. In this study, I reviewed extant literatures on perceived gender discrimination, perceived organizational justice, perceived external organizational justice, trust in organization, trust in supervisor, job satisfaction, organizational commitment, turnover intention, and corporate social responsibility. I proposed and used structural equation modeling to test the models of the relationships among these constructs to understand how people’s perceived gender discrimination is related …

Exploring The Effect Of Practice On Adverse Impact Using A Measure Of Cognitive Ability, Derrick Mcdonald

Doctoral Dissertations

Cognitive ability testing and cognitively loaded measures in employee selection have been utilized, developed, and improved upon for over a century; however, it is not without its faults. Two major problems facing cognitive ability tests are their tendency to produce adverse impact when used in selection systems and the costs associated with creating a well-constructed measure. This paper proposed that Automated Item Generation (AIG) may provide a solution to both of those problems. The first study focused on the construct validation of the Katyem Object Tracking Assessment (KOTA), a nonverbal AIG measure of fluid intelligence, that would allow test takers …

The Role Of Video Game Play, Gender Roles, And Career Decision Self-Efficacy In Development Of Stem Career Interests & Motivation, Michael Saunders

Doctoral Dissertations

The gender wage gap, disadvantaging working women, continues to grow despite progress toward women’s rights and occupational equity. With the world economy prioritizing growth in technological industries, the underrepresentation of women in science, technology, engineering, and mathematics (STEM) fields perpetuates systemic gender inequity. Further, given traditional social gender roles, women and girls may be less likely than boys and men to pursue STEM careers. Though specialized programs seek to grow the number of girls and young women engaged in STEM-related education and prepare them for the growing demand for STEM laborers, these programs are regional, seasonal, and not widely available …

Credit Card Security System And Fraud Detection Algorithm, Baker Al-Smadi

Doctoral Dissertations

Credit card fraud is one of the most critical threats affecting individuals and companies worldwide, particularly with the growing number of financial transactions involving credit cards every day. The most common threats are likely to come from database breaches and identity theft. All these threats threat put the security of financial transactions at severe risk and require a fundamental solution.

This dissertation aims to suggest a secure online payment system that significantly improves credit card security. Our system can be particularly resilient to potential cyber-attacks, unauthorized users, man-in-the-middle, and guessing attacks for credit card number generation or illegal financial activities …

Exploring The Effect Of Occlusion On A Computerized Mental-Rotation Test: Implications For Automatic Item Generation, Swadeep Patel

Doctoral Dissertations

ABSTRACT Radicals are characteristics that impact psychometric properties, such as item difficulty in tests. Within the mental-rotation test literature, occlusion and structure have been shown to contribute to item difficulty but require further study to be used within the context of automatic item generation (AIG). This study investigated whether high or low occlusion functions as a meaningful radical for Shepard-Metzler Mental Rotation Test (SMMRT) items. Thirty-two items containing computer-generated images of 3D block figures were administered to a sample of 180 participants on MTurk. After cleaning and removing careless responders from the sample, the data for 70 participants were analyzed …

How Are The Collaborative Efforts Of The Transition Plan Team Viewed By Its Members, Teresa Henderson

Doctoral Dissertations

The views of a transition/IEP team members of the collaborative efforts of each other have had little or limited viewing. Annually there are approximately six million special education students in the United States of America (Samuels, 2017). While in high school, these students and their transition/IEP team are tasked with preparing them for adult life (U.S. Department of Education [USDOE], 2018). The team’s collaborative efforts are a necessary component of ensuring the success of each student’s adult life (Michaels & Ferrara, 2005).

For students to find success after high school, all transition/IEP team members need to collaborate as best as …

Multi-Scale Computational Modeling Of Metal/Ceramic Interfaces, Abu Shama Mohammad Miraz

Doctoral Dissertations

Multi-scale atomistic calculations were carried out to understand the interfacial features that dictate the mechanical integrity of the metal/ceramic nanolaminates. As such, first principles density functional theory (DFT) calculations were performed to understand the electronic and atomistic factors governing adhesion and resistance to shear for simple metal/ceramic interfaces, whereas molecular dynamics (MD) simulations were performed to observe the impact of interfacial structures, such as misfit dislocation network geometries and orientation relationships, on interfacial mechanical properties.

For the DFT investigation, we choose metals with different crystal structures, namely - Cu (fcc), Cr (bcc) and Ti (hcp) along with a variety of …

Existence Of Mutual Stabilization In Chaotic Neural Models, John Parker

Doctoral Dissertations

Recent work has demonstrated that interacting chaotic systems can establish persistent, periodic behavior, called mutual stabilization, when certain information is passed through interaction functions. In particular, this was first shown with two interacting cupolets (Chaotic Unstable Periodic Orbit-lets) of the double scroll oscillator. Cupolets are highly accurate approximations of unstable periodic orbits of a chaotic attractor that can be generated through a control scheme that repeatedly applies perturbations along Poincaré sections. The decision to perturb or not to perturb the trajectory is determined by a bit in a binary control sequence. One interaction function used in the original cupolet research …

Mathematical Analysis Of A Model Of Blood Flow Through A Channel With Flexible Walls, Madeline Mayes Edwards

Doctoral Dissertations

The present research is devoted to the problem of stability of the fluid flow moving in a channel with flexible walls and interacting with the walls. The walls of the vessel conveying fluid are subject to traveling waves. Experimental data shows that the energy of the flowing fluid can be transferred and consumed by the structure (the walls), which induces “traveling wave flutter.” The problem of stability of fluid-structure interaction splits into two parts: (i) stability of fluid flow in the channel with harmonically moving walls and (ii) stability of solid structure participating in the energy exchange with the flow. …

An Improv-Able Legacy: Shining The Composition Spotlight On Viola Spolin’S Improvisational Pedagogy, Cory Richard Chamberlain

Doctoral Dissertations

This dissertation is an archival study of the works of Viola Spolin who is considered by many to be the founding mother of improvisational theater. During her life she published Improvisation for the Theater which is essential reading for anyone interested in doing improvisational theater as well as Theater Games for The Classroom where she adapted some of her techniques and games to an educational setting outside of theater. Along with these works, I was able to examine two of her unpublished works, a handbook on education and What’s Your Score? as well as various notes, correspondences and interviews housed …

Speeding-Up A Random Search For The Global Minimum Of A Non-Convex, Non-Smooth Objective Function, Arnold C. Englander

Doctoral Dissertations

The need to find the global minimum of a highly non-convex, non-smooth objective function over a high-dimensional and possibly disconnected, feasible domain, within a practical amount of computing time, arises in many fields. Such objective functions and/or feasible domains are so poorly-behaved that gradient-based optimization methods are useful only locally – if at all. Random search methods offer a viable alternative, but their convergence properties are not well-studied. The present work adapts a proof by Baba et al. (1977) to establish asymptotic convergence for Monotonic Basin Hopping, a random search method used in molecular modeling and interplanetary spacecraft trajectory optimization. …

Performance Evaluation And Review Framework Of Robotic Missions (Perform): Autonomous Path Planning And Autonomy Performance Evaluation, Allisa Dalpe

Doctoral Dissertations

The scope of this work spans two main areas of autonomy research 1) autonomous path planning and 2) test and evaluation of autonomous systems. Path planning is an integral part of autonomous decision-making, and a deep understanding in this area provides valuable perspective on approaching the problem of how to effectively evaluate vehicle behavior.

Autonomous decision-making capabilities must include reliability, robustness, and trustworthiness in a real-world environment. A major component of robot decision-making lies in intelligent path-planning. Serving as the brains of an autonomous system, an efficient and reliable path planner is crucial to mission success and overall safety. A …

Exploring Mathematical Connections Preservice Teachers Make Between Abstract Algebra And Secondary Mathematics: Implications For Learning And Teaching, Cammie Gray

Doctoral Dissertations

Abstract algebra has been identified as an important course for preservice secondary mathematics teachers because much of the abstract algebra content is connected to, and thus relevant for, secondary mathematics teaching (Wasserman et al., 2017). However, many preservice teachers do not recognize the usefulness of an undergraduate abstract algebra course and see no relation between abstract algebra and secondary school mathematics (Christy & Sparks, 2015; Ticknor, 2012). While much of the research regarding preservice teachers making connections to secondary school mathematics in abstract algebra has been conducted in courses designed for preservice teachers, the research suggests that most universities with …

Development Of A Sunken Oil Transport Tool Using Mesoscale Experiments, Melissa Denise Gloekler

Doctoral Dissertations

Oil spilled into fresh or saline water can float, become submerged in the water column (i.e., submerged oil), or sink to the bottom (i.e., sunken oil). Once introduced to the environment, oil can negatively impact ecological and public health, and the economy. Non-floating oil spills pose unique challenges to responders including the complexity of trajectory modeling; the inability to detect, track and recover oil due to limited visibility; the lack of readily deployable response technology; and limited understanding of how bottom substrate dynamics influence its fate and behavior. This dissertation research determined that the driving factors used to predict sunken …

An Empirical Evaluation Of Visual Cues For 3d Flow Field Perception, Andrew Harlan Stevens

Doctoral Dissertations

Three-dimensional vector fields are common datasets throughout the sciences. They often represent physical phenomena that are largely invisible to us in the real world, like wind patterns and ocean currents. Computer-aided visualization is a powerful tool that can represent data in any way we choose through digital graphics. Visualizing 3D vector fields is inherently difficult due to issues such as visual clutter, self-occlusion, and the difficulty of providing depth cues that adequately support the perception of flow direction in 3D space. Cutting planes are often used to overcome these issues by presenting slices of data that are more cognitively manageable. …

The Impact Of Block Scheduling On Student Achievement, Graduation Rate, And Attendance At The High School Level, Sedric G. Clark

Doctoral Dissertations

The purpose of this study was to determine the impact of block scheduling on student achievement, graduation rate, and attendance at the high school level. The study was a mixed methods study that compared existing data from three high schools from the same school district in a southern state which all moved from a traditional schedule to a block schedule and back to a traditional schedule over the same period of time. The study results included the comparison of composite ACT scores and attendance rates from the years pre-block implementation, the years of block implementation, and the years post-block implementation. …

Performance And Retention Of Female Engineering Students When Placed In A Gender Parity Course, Allie Corinne Deleo-Allen

Doctoral Dissertations

Though women earn the majority of bachelor’s degrees in the United States of America, they are in the vast minority of those earning degrees in engineering, only 24%. In an effort to ultimately increase the number of women graduating with degrees in engineering, our study focused on improving the retention of first-year female students.

We set out to discover if female engineering students, who traditionally are in the minority of their student body, would have an increase in their performance and retention when placed in a manipulated course environment of gender parity (50% women, 50% men). Our study followed 129 …

Non-Academic Support Math Faculty Members Provide In Developmental Accelerated And Corequisite Support Courses In California Community Colleges, David Vakil '92

Doctoral Dissertations

To guide practitioners of rapidly evolving developmental math reform in community colleges, this study surveyed California community college math faculty who taught accelerated developmental courses or corequisite support courses. The survey was conducted during the early implementation phase of both course types, during spring and fall 2018 terms. This study measured faculty’s self-reported provision of forms of non-academic support, frequency of implementation, and reasons faculty believed the support would help students succeed. The literature review guided grouping non-academic support into five forms: nurturing, helping students’ motivation, providing a growth mindset theory of intelligence, helping provide social integration, and helping to …

Theoretical Study Of Magnetic Particles In A Shear Flow Subjected To A Uniform Magnetic Field, Christopher A. Sobecki

Doctoral Dissertations

"Magnetic manipulation of non-spherical magnetic microparticles is important for applications in shape-based and magnetic-based separations such as waste management, disease diagnostics, drug delivery, and mining. Manipulations of magnetic microparticles also include chain formation to assemble compositions for electronics, drug loading designs, and magnetorheological fluids for smart armor, hydraulic brakes, and dampers. In microfluidic devices, separation-formation-effectiveness depends on the shape of the channel, the shear rate, and the magnetic field strength and direction.

Particle separation and chain formation involved highly complex and computational expense-demanding studies in microfluidic devices, magnetic fields, and particle- particle/wall interactions. This research took complex experimental studies and …

Fiber Optic Sensors For Industry And Military Applications, Yiyang Zhuang

Doctoral Dissertations

"Fiber optic sensors (FOSs) have been widely used for measuring various physical and chemical measurands owing to their unique advantages over traditional sensors such as small size, high resolution, distributed sensing capabilities, and immunity to electromagnetic interference. This dissertation focuses on the development of robust FOSs with ultrahigh sensitivity and their applications in industry and military areas.

Firstly, novel fiber-optic extrinsic Fabry-Perot interferometer (EFPI) inclinometers for one- and two-dimensional tilt measurements with 20 nrad resolution were demonstrated. Compared to in-line fiber optic inclinometers, an extrinsic sensing motif was used in our prototype inclinometer. The variations in tilt angle of the …

Three Essays In Applied Microeconomics: Spillover Effects Of Anti Discrimination And Anti Violence Policies, Gokhan Kumpas

Doctoral Dissertations

In this research, I examine the intended and unintended consequences of three highly debated policies at the state and federal level: enactment of Title IX, state anti-bullying laws, and warrantless arrest laws aimed at curbing domestic violence. My first essay examines the causal relationship between athletic participation and means-tested program participation. I use the variation in the implementation of Title IX and find that a 30 percentage-point increase in female athletic participation induced by Title IX increased program participation among 25 to 40-year-old females by 2.8 percentage-points. This effect persists across SNAP, TANF, and Medicaid recipiency. Event study analysis and …

Characterizing Forest Stands Using Unmanned Aerial Systems (Uas) Digital Photogrammetry: Advancements And Challenges In Monitoring Local Scale Forest Composition, Structure, And Health, Benjamin T. Fraser

Doctoral Dissertations

Present-day forests provide a wide variety of ecosystem services to the communities that rely on them. At the same time, these environments face routine and substantial disturbances that direct the need for site-specific, timely, and accurate monitoring/management (i.e., precision forestry). Unmanned Aerial Systems (UAS or UAV) and their associated technologies offer a promising tool for conducting such precision forestry. Now, even with only natural color, uncalibrated, UAS imagery, software workflows involving Structure from Motion (SfM) (i.e., digital photogrammetry) modelling and segmentation can be used to characterize the features of individual trees or forest communities. In this research, we tested the …