Digital Commons Network^™

Teacher Training And Mentoring: The Relationship Between Classroom Practices And Student Outcomes, Cledenin Veras

All Dissertations

Dominican students have the lowest performance scores in science, math, and reading comprehension compared to students across the region, according to national (Minerd, 2018) and International evaluations (TERCE, 2014). While many factors are linked to these results, teacher performance is considered an essential element (OECD, 2015) that needs to be addressed.

Project USAID READ is an initiative of the United States Agency for International Development (USAID), implemented by the Universidad Iberoamericana (UNIBE). The Project's purpose is to improve the reading and writing skills of Primary Level students, by supporting the implementation of the curriculum and promoting appropriate learning environments. Training …

Managing Risk For Power System Operations And Planning: Applications Of Conditional Value-At-Risk And Uncertainty Quantification To Optimal Power Flow And Distributed Energy Resources Investment, Thanh To

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Renewable energy sources are indispensable components of sustainable electrical systems that reduce human dependence on fossil fuels. However, due to their intermittent nature, there are issues that need to be addressed to ensure the security and resiliency of these power systems. This dissertation formulates several practical problems, from an optimization perspective, stemming from the increasing penetration of intermittent renewable energy to power systems. A number of Optimal Power Flow (OPF) formulations are investigated and new formulations are proposed to control both operations and planning risks by utilizing the Conditional Value–at–Risk (CVaR) measure. Our formulations provide system operators and investors analysis …

Advancements In Gaussian Process Learning For Uncertainty Quantification, John C. Nicholson

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Gaussian processes are among the most useful tools in modeling continuous processes in machine learning and statistics. The research presented provides advancements in uncertainty quantification using Gaussian processes from two distinct perspectives. The first provides a more fundamental means of constructing Gaussian processes which take on arbitrary linear operator constraints in much more general framework than its predecessors, and the other from the perspective of calibration of state-aware parameters in computer models. If the value of a process is known at a finite collection of points, one may use Gaussian processes to construct a surface which interpolates these values to …

Optimization Of Modular, Long-Range, Ultra-Fast Optical Tweezers With Fluorescence Capabilities For Single-Molecule And Single-Cell Based Biophysical Measurements, Subash C. Godar

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An Optical tweezer is a tightly focused laser beam that applies and senses precise and localized optical force to a dielectric microsphere and offers a unique and effective tool for manipulating the single cell or cell components, including nucleotides and dynein motor proteins. Here, I used highly stabilized optomechanical components and ultra-sensitive detection modules to significantly improve the measurement capabilities over a wide range of temporal and spatial scales. I combined the optical tweezer-based force spectroscopy technique with fluorescence microscopy to develop an integrated high-resolution force-fluorescence system capable of measuring displacements at sub-nanometer, forces at sub-piconewton over a temporal range …

On The Frontlines Of Covid-19: A Jd-R Approach To Better Understand Emergency Medicine Clinicians' Psychological Well-Being, Riley Mccallus Pegram

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Healthcare organizations have been heavily impacted by the COVID-19 pandemic, with emergency departments (EDs) facing especially large burdens. Increased patient volumes, fewer opportunities to disengage from work, and the persistence of the pandemic over many months continue to place demands on emergency medicine clinicians (EMC) and may elevate their levels of psychological stress. Psychological resilience and meaningful work experiences may protect EMC from these negative effects but may also be negatively impacted by high levels of ED crowding. Using the Job-Demands Resources model as a theoretical framework, this dissertation sough to explore how ED crowding (measured objectively and subjectively), psychological …

Wetland Uranium Transport Via Iron-Organic Matter Flocs And Hyporheic Exchange, Connor J. Parker

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Uranium (U) released from the M-Area at the Department of Energy Savannah River Site into Tims Branch, a seasonal wetland and braided stream system, is estimated to be 43,500 kg between 1965 and 1984. The motivation for this work is the uranium’s persistence in the wetland for decades, where it is estimated that 80% of the U currently remains in the Tims Branch wetland. U has begun to incorporate into wetland iron (Fe) and carbon cycles, associating with local Fe mineralogy and deposits of rich wetland organic matter (OM). The objective of this work is to characterize the chemical phases …

Investigating The Effects Of Topology On The Fracture And Failure Mechanisms Of Low Density Metamaterials, Kaitlynn Melissa Conway

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Advances in additive manufacturing have enabled the creation of low density metamaterials with fine features and complex topographies. These new metamaterial topologies and size scales not previously possible broaden the spectrum of lightweight materials with unique properties that are advantageous in a variety of applications. There however is a lack of understanding of metamaterial failure and fracture behaviors. Studies tend to report only a few material properties rather than a comprehensive description of behavior. Due to this, there is a hesitancy to incorporate metamaterials into engineering designs despite proven remarkable properties. This work seeks to investigate in three parts the …

Performance Of Geotechnical Systems Under Extreme Hydroclimatic Events Using Finite Element Modeling, Tharshikka Vickneswaran

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Failure of geotechnical systems during hydroclimatic events such as heavy rainfall, flood, and drought often leads to significant socio-economic loss. The time-dependent stability and deformation behaviors of geotechnical systems subjected to hydroclimatic events must be investigated using a coupled flow-deformation formulation because the strength and deformation parameters vary with the degree of saturation and/or matric suction of the soil. Although the impacts of the hydroclimatic events on the geotechnical systems are assessed and summarized in the previous studies, all the analyses were carried out in a loosely coupled manner and/or uncoupled manner without considering the effects of water flow in …

Characterization Of Water Flow And Solute Transport Driven By Preferential Flow In Soil Vadose Zone, Abdullah Al Mamun

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The vadose zone acts as a buffer zone between the ground surface and the aquifers underneath and controls the transmission of infiltrating water and contaminants, for example, pesticides and chemical spills. Therefore, understanding the flow and transport processes that dominate the vadose zone is important. Macropores are ubiquitous and particularly found in abundance in the vadose zone. These macropores facilitate preferential flow, through which water travels rapidly deep into the soil, bypassing most of the porous matrix. Preferential flow and transport have environmental significance as their processes impact hydrology, ecology, agriculture, subsurface contamination, and waste management sectors. Thus, the overall …

Environmental Exploration With Long, Thin Tendril Robots, Or Building Plant Based Robots And Teaching Them How To Feel, Michael Benjamin Wooten

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Continuum robots offer unique potential benefits for environmental exploration, notably in using their maneuverability to navigate congested environments. In this dissertation, we show how circumnutation, a motion strategy, commonly employed by plants, can be implemented, and usefully exploited, with continuum robots. We discuss how the kinematics of circumnutation, which combines local backbone growth with periodic backbone bending, can be created using extensible continuum robot hardware. The underlying kinematics are generated by adapting kinematic models of plant growth. We illustrate the effectiveness of that approach with experimental results with a tendril robot exploring a congested environment. However, significant challenges remain in …

Improved First-Order Techniques For Certain Classes Of Convex Optimization, Trevor Squires

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The primary concern of this thesis is to explore efficient first-order methods of computing approximate solutions to convex optimization problems. In recent years, these methods have become increasingly desirable as many problems in fields such as machine learning and imaging science have scaled tremendously. Our aim here is to acknowledge the capabilities of such methods and then propose new techniques that extend the reach or accelerate the performance of the existing state-of-the-art literature.

Our novel contributions are as follows. We first show that the popular Conditional Gradient Sliding (CGS) algorithm can be extended in application to objectives with H\"older continuous …

Valorization Of Biopolymers And Biomass To Produce Materials For A More Circular Economy, Moira Lauer

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With a globally increasing population and largely unchecked consumption of raw materials, human society is on track for devastating consequences. Two industries responsible for utilizing massive amounts of raw materials and generating equally gargantuan quantities of waste are the packaging and infrastructure sectors. In 2017 in Europe, for example, packaging reached a record 173 kg of packaging waste per capita. One of the largest packaging consumers is the food industry, in which 40% of packaging is made of petroleum-derived single-use plastic, leading to a massive carbon imbalance. “The Built Environment,” on the other hand, is responsible for about 50% of …

The Future Of Higher Education For Land-Grant Institutions: Considerations Beyond Short-Term Strategic Planning, Andrew Edmunds

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This research addresses future challenges for land-grant universities and calls on administrators to look beyond short-term strategic planning. Chapter One frames the research problem and presents a brief history of U.S. higher education defined by disruption and evolution. Statistical models provide a basis to identify future challenges for land-grant universities. I then propose to address those challenges by investigating University Industry Partnerships (UIP), increasing research productivity, and fostering sense of belonging for part-time graduate students. I use a systematic literature review of UIP structuring practices to reveal how UIPs are structured by time, personnel, and flexible horizontal organizational structures. I …

An Exploratory Multiple-Case Study Of Nepal’S Science Teacher Educators’ Knowledge And Practices Of Active Learning And Culturally Responsive Teaching, Sunil Pokhrel

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The benefits of implementing active learning (AL) embedded with culturally responsive teaching (CRT) practices are well established: students’ deep learning of science is promoted and the achievement gaps between students of majority and minority backgrounds are reduced. Unfortunately, the acceptance for AL and CRT in Nepal’s science teacher programs is low and implementation is superficial. Using a qualitative multiple-case study, the study examined the understanding of seven Nepali science teacher educators (STE) of AL and CRT practices. The challenges faced by the STEs to implementing these two pedagogies at three of Nepal’s science education-focused Bachelor of Education (B.Ed.) programs were …

“I Can See The Forest For The Trees”: Examining Personality Traits With Trasformers, Alexander Moore

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Our understanding of Personality and its structure is rooted in linguistic studies operating under the assumptions made by the Lexical Hypothesis: personality characteristics that are important to a group of people will at some point be codified in their language, with the number of encoded representations of a personality characteristic indicating their importance. Qualitative and quantitative efforts in the dimension reduction of our lexicon throughout the mid-20^th century have played a vital role in the field’s eventual arrival at the widely accepted Five Factor Model (FFM). However, there are a number of presently unresolved conflicts regarding the breadth and …

Pulse-Coupled Oscillator Networks: Achieving Phase Continuity And Learning Optimal Control In Physical Systems, Timothy Anglea

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In this dissertation, we consider the application of pulse-coupled oscillator theory to real-world, physical networks. When the phase of an oscillator is associated with a physical measure, such as clock timing or robotic heading, discontinuous adjustments of the oscillator's phase is undesirable and potentially disadvantageous. Rather, continuous adjustment of the oscillator phase value is needed over a certain amount of time. To ensure that both synchronization and desynchronization can still be achieved under the constraint of continuous phase value changes, we pursue a novel approach to analyze the generalization of a pulse-coupled oscillator network with a time-varying coupling strength. We …

Synthesis And Molecular Processes Governing Self-Healing Polymeric Materials, Siyang Wang

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Self-healing polymers capable of recovering from physical damages are promising materials for advanced technologies. In these studies, we developed routes to achieve self-healable properties in acrylic-based copolymers that rely on non-covalent dipolar interactions present in essentially all polymeric materials. Using a combination of spectroscopic tools, thermo-mechanical analysis, and molecular dynamic (MD) simulations, these studies have shown that dipolar interactions lead to conformational changes of macromolecular segments which, in turn, result in self-healing without external intervention. This dissertation also describes the development of novel self-healable acrylic-based covalent adaptable networks (CANs) that combine reprocessing and self-healing properties. The utilization of dipolar interactions …

Determining The Value Of Ecosystem Services Provided By Green Stormwater Infrastructure In Coastal South Carolina, Joan U. Ureta

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Rapid urbanization changes the natural hydrology of a landscape, making stormwater management a crucial aspect of land development. As the fastest growing ecosystem globally, an innovative way of managing stormwater is needed to address the increase in urban run-off. In coastal South Carolina, stormwater practices have been widely adopted at the neighborhood level, yet threat of flooding is becoming more evident as the urban population and development continue to rise.

To determine the importance of stormwater practices to coastal residents, we assessed perception on stormwater practices and programs at different decision levels— 1) household, 2) neighborhood, and 3) city/county. Results …

Synthesis Of Fluorinated Monomers And Polymers For Various Applications, Cassandra J. Hager

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The world of industry utilizes a variety of polymers for various applications in many prominent fields. From electronics to food storage, the versatility of this class of chemistry has been widely proven. The Thrasher research group undertook a program dedicated towards the development of a library of fluorinated materials that focused on the synthesis and characterization of perfluoroalkoxy (PFA) copolymers of tetrafluoroethylene (TFE) and perfluoroalkyl trifluorovinyl ethers. One aim of the project was to improve upon the mechanical strength and wearability of commercial PFA resins by incorporating bulkier perfluoroalkoxy trifluorovinyl ether monomers into these copolymers. In addition to focusing on …

A Study Of Scheduling Problems With Sequence Dependent Restrictions And Preferences, Nitin Srinath

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In some applications like fabric dying, semiconductor wafer processing, and flexible manufacturing, the machines being used to process jobs must be set up and serviced frequently. These setup processes and associated setup times between jobs often depend on the jobs and the sequence in which jobs are placed onto machines. That is, the scheduling of jobs on machines must account for the sequence-dependent setup times as well. These setup times can be a major factor in operational costs. In fabric dyeing processes, the sequence in which jobs are processed is also important for quality, i.e., there is a strong preference …

Exploring The Glow Of The Universe In Gamma-Rays And Hunting Distant Agn, Changam Meenakshi Rajagopal

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The entirety of the γ-ray radiation permeating our Universe is encoded in the extragalactic γ-ray background. This is a superposition of resolved sources, mostly powerful relativistic jets powered by supermassive black holes, i.e., blazars, and an unresolved isotropic component, aka, the diffuse isotropic gamma-ray background (IGRB). Studying the IGRB can help unveil its composition, as well as unearth multi-messenger relationships between the intensities of PeV neutrinos, ultra high energy cosmic rays (> 1018 eV), and sub-TeV γ-rays. The comparable energy budgets of these three phenomena (neutrinos, UHECR, and γ-rays) indicates a physical connection or a common source amongst them. On …

Supertertiary Structural Dynamics Modulate Function In Postsynaptic Density Protein 95, George L. Hamilton Iii

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Proteins, RNA, and DNA serve as the primary sub-cellular machinery that give rise to the necessary functions of life. The long-standing paradigm has been that the structures of biomolecules, or the arrangement of the subunits that make up a biomolecule, determine biological function. However, biomolecules are not static objects. Instead, they often undergo structural rearrangements that are crucial to enabling and regulating their functions. In my thesis I present several studies of the interplay between the structures, dynamics, and functions of biomolecules that combine experimental fluorescence spectroscopy and computational methods to probe these systems at the single-molecule level. In particular, …

Double Tolerance Design In Stochastic Production Environments, Di Liu

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In a production process, it is impossible to produce parts with exact specifications. Thus, specific ranges, i.e., tolerances, are commonly employed to define intervals for the quality characteristics of conforming products (Wu & Tang (1998)). Usually, a product is deemed conforming when the measurement of the quality characteristic falls within the tolerance. If the measurement falls outside the tolerance, the product is nonconforming and it can be reworked or scrapped. One of the important engineering problems commonly faced by practitioners is to determine optimal engineering tolerances to be used in production. As a result, tolerance design techniques are widely used …

Some Improved Markov Chain Convergence Rates, Fun Choi John Chan

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Explicit convergence rates to equilibrium are established for non reversible Markov chains not having an atom via coupling methods. We consider two Markov chains having the same transition function but different initial conditions on the same probability space, that is, a coupling. A random time is constructed so that subsequent to the random time the two processes are identical. Exploiting a shadowing condition, we show that it is possible to bound the tail distribution of the random time using only one of the chains. This bound gives the convergence rate to equilibrium for the Markov chain. The method is then …

Groundwork For The Development Of Gpu Enabled Group Testing Regression Models, Paul Cubre

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In this dissertation, we develop novel techniques that allow for the regression analysis of data emerging from group testing processes and set the groundwork for graphic processing units (GPU) enabled implementations. Group testing primarily occurs in clinical laboratories, where it is used to quickly and cheaply diagnose patients. Typically, group testing tests a pooled specimen--several specimens combined into one sample--instead of testing individual specimens one-by-one. This method reduces costs by using fewer tests when the disease prevalence is low. Due to recent advances in diagnostic technology, group testing protocols were extended to incorporate multiplex assays, which are diagnostic tests that, …

Extractive Membranes For The Detection And Screening Of Waterborne Plutonium, James Foster

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The development of rapid screening tools for special nuclear materials remains a crucial focus for nonproliferation efforts. Traditional approaches for the analysis of trace-level Pu isotopes in water requires tedious and time-consuming sample preparation steps that do not lend well to expeditious screening. Therefore, a novel analytical method that combines both Pu concentration and source preparation into a single detection system would make for an invaluable tool for nuclear security applications. Extractive membranes absorbers can help to fulfill this role as they are capable of concentrating Pu to detectable limits while subsequently serving as alpha spectrometry sample sources. In Chapter …

Control, Decision-Making, And Learning Approaches For Connected And Autonomous Driving Systems With Humans-In-The-Loop, Fangjian Li

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By virtue of vehicular connectivity and automation, the vehicle becomes increasingly intelligent and self-driving capable. However, no matter what automation level the vehicle can achieve, humans will still be in the loop despite their roles. First, considering the manual driving car as a disturbance to the connected and autonomous vehicles (CAVs), a novel string stability is proposed for mixed traffic platoons consisting of both autonomous and manual driving cars to guarantee acceptable motion fluctuation and platoon safety. Furthermore, humans are naturally considered as the rider in the passenger vehicle. A human-centered cooperative adaptive cruise control (CACC) is designed to improve …

Automated Parallel Optimization Of Simulation Parameters Using Modified Nelder-Mead Simplex Algorithm, Erina Mills

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Computational simulations used in many fields have parameters that define models that are used to evaluate simulated properties. When developing these models, the goal is to choose the parameters that best replicate a set of desired properties. Mathematical optimization methods can be used to optimize the simulation parameters by defining a function that uses simulation parameters as input and outputs a value describing how well a set of experimental properties are reproduced.

Because simulated properties are often calculated using stochastic sampling methods, this optimization involves an objective function that is noisy and expensive to evaluate. Also, optimization of the simulation …

Cell Tracking At Low Frame Rate Using Deep Learning And Bayesian Integration, Xiang Zhang

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Tracking cells over time is a fundamental task in live-cell imaging, and often requires costly manual analysis if images are not acquired with high enough frame rate. Acquiring high frame rate images, however, can limit the number of conditions explored and cells analyzed, and contribute to photobleaching, which makes fluorophores dimmer and phototoxicity, which affects cell health and renders the resulting data unusable.

Assuming a relatively high frame rate in image acquisition, state-of-the-art cell tracking approaches rely on either spatial proximity or morphological similarity to link cells in consecutive frames. The problem is that, at low frame rate, both approaches …

Exact Solutions For The Evolution Of Directed Acyclic Reaction Networks With Applications To Nucleosynthesis, Norberto Davila

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Nucleosynthesis is the collection of processes that are responsible for the vast diversity of nuclear species seen in nature. Computational models are upbiquitous throughout the field of astrophysics and are used to attempt to reproduce the observed abundances of these nuclear species. Though these models can be quite robust, we find a lack in the field highlighting the importance of reaction rates to how the final abundances are obtained. These various reaction rates critically dictate the reaction pathways that contribute to the final abundances, and these pathways are highly dependent on the nuclear reaction rates themselves. Rather than focus on …