Physical Sciences and Mathematics Commons^™

A Spectroscopic Survey Of Primitive Main Belt Asteroid Populations, Anicia Arredondo-Guerrero

Electronic Theses and Dissertations, 2020-2023

Primitive asteroids have remained mostly unprocessed since their formation, and the study of these populations has implications about the conditions of the early solar system and the evolution of the asteroid belt. This spectroscopic study of inner main-belt (IMB) primitive asteroids addresses three central objectives: 1) determine the origin and composition of objects in the near-Earth object population, particularly spacecraft targets; 2) test theories of how processes such as space weathering and aqueous alteration affect surface properties of small, low-albedo bodies; and 3) explore how primitive objects in the background population (i.e., asteroids not belonging to dynamical families) relate to …

Exploring New Materials As Promising Electrocatalysts For The Generation Of A Clean And Renewable Energy Source, Tyler Campbell

Electronic Theses and Dissertations, 2020-2023

This work presents the research of myself, my advising professor, and our collaborators in first-principles studies of several catalytic materials for improving the efficiency and economics of hydrogen fuel cells, focusing on the oxygen reduction reaction (ORR) at the cathode, CO removal and the hydrogen oxidation reaction (HOR) at the anode, and the redox reactions used for water splitting through photocatalysis. We use a computational design approach to analyze the reaction thermodynamics, applying density functional theory (DFT) for most calculations. We find that, through a subversion of the linear scaling approximation for surface reactivity, an Au monolayer deposited on the …

Index-Based Approach With Remote Sensing For The Assessment Of Extreme Weather Impact On Watershed Vegetation Dynamics, Kushan Bellanthudawage

Electronic Theses and Dissertations, 2020-2023

Spatial technologies such as satellite remote sensing can be used to identify vegetation dynamics over space and time, which play a critical role in earth observations. Biophysical and biochemical features associated with vegetation cover can then be used to elucidate climate change impact such as floods and droughts on ecosystem that may in turn affect watershed-scale water resources management. Unlike single flood or drought event, intermittent extreme weather events may exert more physiological and biological pressures on the canopy vegetation. This study aims to investigate the climate change impacts on canopy vegetation, which occurred from March 2017 to October 2017 …

Dual Beam Frequency Comb Ftir Spectroscopy, Connor Kelly

Electronic Theses and Dissertations, 2020-2023

A visible and Infrared (IR) range dual beam frequency comb Fourier transform spectrometer was developed. Using dual mode-locked Ti:Sapphire lasers a comb-interferogram was generated in the visible range. This spectrum was calculated and used to measure the transmittance of a Nd-doped crystal. The system was further developed to generate an IR interferogram by Difference Frequency Generation (DFG) using a Gallium Selenide (GaSe) crystal placed in the mode-locked pump beam. Numerical work was done to calculate the expected DFG spectrum confirming the necessary IR range can be reached. This has been conducted in support of an IR holographic spectroscopic microscopy spatial …

Unusual Superconductivity In Topological Nodal Line Semimetal, Riffat Munir

Electronic Theses and Dissertations, 2020-2023

Unconventional superconductivity differs from the conventional one by the pairing mechanism. In conventional or s wave superconductor electrons with opposite spin and momentum form cooper pair and superconductivity occurs as a result of electron phonon interaction. In the unconventional superconductor pairing mechanism is different than that of conventional one , for example p wave pairing where electrons with similar direction of spin forms the cooper pair. Unconventional superconductivity has been observed in systems such as heavy fermion,cuprates, iron based superconductors etc. In recent years topological superconductivity has gained attention due to the combination of topological states in the band sturucture …

Superconductivity And Topological Properties In A Topological Semimetal, K A M Hasan Siddiquee

Electronic Theses and Dissertations, 2020-2023

Topological superconductors (TSCs) in which superconductivity and topological properties are combined are characterized by topologically protected gapless states in the superconducting gaps. Realized in the gapless states of TSCs, Majorana fermions, which are particles and their own antiparticles, have crucial importance in quantum computation and spintronic device applications because of the exotic nature. Despite extensive study for the confirmation of TSCs, the observation of Majorana fermions in bulk superconductors has not been settled yet. Recently, the binary stannide semimetal CaSn3 with a cubic structure has been proposed to be a promising candidate for realizing topological superconductivity. In this dissertation, to …

Towards Improving The Robustness Of Neural Abstractive Summarization, Kaiqiang Song

Electronic Theses and Dissertations, 2020-2023

Recent deep learning and sequence-to-sequence learning technology have produced impressive results on automatic summarization. However, the models have limited insights on the underlying language and it remains challenging for system-generated summaries to be truthful to the original input or cover the most important information. This is especially the case for generating abstractive summaries using neural models. My work aims for a flexible and controllable summarization system that can be adapted to cater to different scenarios. It is designed to incorporate linguistic structure information into deep neural networks, have the capability to produce abstracts by re-using a varying amount of source …

Directional Link Management Using In-Band Full-Duplex Free Space Optical Transceivers For Aerial Nodes, A F M Saniul Haq

Electronic Theses and Dissertations, 2020-2023

Free-space optical (FSO) communication has become very popular for wireless applications to complement and, in some cases, replace legacy radio-frequency for advantages like unlicensed band, spatial reuse, and enhanced security. Even though FSO can achieve very high bit-rate (tens of Gbps), range limitation due to high attenuation and weather dependency has always restricted its practical implementation to indoor application like data centers and outdoor application like Project Loon. Building-to-building communication, smart cars, and airborne drones are potential futuristic wireless communication sectors for mobile ad-hoc FSO networking. Increasing social media usage demands high-speed mobile connectivity for applications like video call and …

Highly Reproducible Electrochemical Sensors Towards Wearable Applications And Pharmaceutical Analysis, Mohammad Rostampour Kakroudi

Electronic Theses and Dissertations, 2020-2023

Ion-selective electrodes (ISEs) are widely used to monitor ions in various applications from environmental to clinical settings and pharmaceutical analysis. ISEs are a type of potentiometric sensor that provides a versatile, cost-effective, and efficient platform towards wearable sensing applications. Among the two different platforms of ISEs (solid-contact and liquid-contact), solid-contact ISEs are superior to ISEs with internal electrolytes (liquid-contact) since they are easy to be miniaturized, can be used in any environment and their portability is facilitated. Unfortunately, mass production and commercialization of such devices is often constrained by the requirement of sensor calibration. Thus, approaches for sensor manufacturing towards …

Regularized Estimations In Some Statistical Problems, Feng Yu

Electronic Theses and Dissertations, 2020-2023

In this dissertation, we consider estimations with regularization in three statistical problems relating to linear time system, stochastic block model and matrix variate regression. In the first part of the dissertation, we specifically investigate Mixture Multilayer Stochastic Block Model, where layers can be partitioned into groups of similar networks, and networks in each group are equipped with a distinct Stochastic Block Model. The goal is to partition the multilayer network into clusters of similar layers, and to identify communities in those layers. The Mixture Multilayer Stochastic Block Model was introduced by Bing-yi Jing [2020] and a clustering methodology, TWIST, is …

Enhancing Agroecosystem Phosphorus Management: Root Phenotyping And Decomposition For Improved Phosphorus Cycling, Rebecca Kay Mcgrail

Theses and Dissertations--Plant and Soil Sciences

Plant roots are often overlooked when making nutrient management decisions. Evaluating differences in P acquisition strategies and cycling resulting from years of shoot-specific plant breeding will aid in reducing fertilizer inputs, with the ultimate goal of improving economic sustainability of crop production and preservation of ecosystem services. To achieve this goal, this research screened a diverse panel of winter wheat cultivars that included old and modern, dwarfed and wild type varieties for physical and chemical root phenotypes related to P acquisition. Old cultivars had larger root systems with more roots that grew two times faster than intermediate/modern cultivars. Wild type …

Towards Enabling Explanation In Safety-Critical Artificial Intelligence Systems, Andy Michel

Electronic Theses and Dissertations, 2020-2023

With the advancement of accelerated hardware in recent years, there has been a surge in the development and application of intelligent systems. Deep learning systems, in particular, have shown exciting results in a wide range of tasks: classification, detection, and recognition. Despite these remarkable achievements, there remains an active research area that aims to increase the robustness of those systems in critical domains. Deep learning algorithms have proven to be brittle against adversarial attacks. That is, carefully crafted adversarial inputs can consistently trigger an erroneous prediction from a network model. Hence the motivation of this dissertation, we study prominent adversarial …

Identification And Detection Of Cosmetics Transferred During Close Personal Attacks, Kandyss Najjar

Electronic Theses and Dissertations, 2020-2023

New types of trace evidence are necessary to account for the potential lack of evidence found during criminal investigations, due to perpetrators' awareness of common types such as latent prints, hair, and DNA. During cases involving close personal contact, such as sexual assault, perpetrators may not be aware of the possible transfer of cosmetics from or onto the victim or crime scene. Therefore, this project focused on analyzing and developing characterization schemes for cosmetic components, specifically glitter and shimmer particles. Analysis of these particles was performed using various analytical techniques, such as microscopy and spectroscopy techniques, and the developed characterization …

Chemical Vapor Deposition Growth Of Transition Metal Dichalcogenides And Their Heterostructure Integration, Sajeevi Sankalpani Withanage

Electronic Theses and Dissertations, 2020-2023

Two-dimensional transition metal dichalcogenides (TMDs) are of great interest for the discovery of many novel physics owing to their extraordinary electrical, optical, mechanical properties as well as many promising applications including heterojunctions. To realize the overreaching goals of these materials, it is important to develop scalable growth techniques and investigate the role of different growth parameters on the resulting material properties. In this dissertation, I study, (i) controllable and reproducible growth of monolayer molybdenum disulfide (MoS2) via chemical vapor deposition (CVD), (ii) the role of growth temperature on the properties of large area MoS2 thin films grown via thermal vapor …

Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence

Theses and Dissertations

Combining vibrating mesh nebulizers with additional new technologies leads to substantial improvements in pharmaceutical aerosol delivery to the lungs across therapeutic administration methods. In this dissertation, streamlined components, aerosol administration synchronization, and/or Excipient Enhanced Growth (EEG) technologies were utilized to develop and test several novel devices and aerosol delivery systems. The first focus of this work was to improve the poor delivery efficiency, e.g., 3.6% of nominal dose (Dugernier et al. 2017), of aerosolized medication administration to adult human subjects concurrent with high flow nasal cannula (HFNC) therapy, a form of continuous-flow non-invasive ventilation (NIV). The developed Low-Volume Mixer-Heater (LVMH) …

Understanding Patterns And Functional Impacts Of An Invasive Tree And Its Biological Control In A Riparian System, Annie L. Henry

Electronic Theses and Dissertations

Invasive species have become an inextricable part of the landscape, particularly in riparian plant communities, and removal is often a key component of restoration programs. Biological control (biocontrol) is a method of removal that is often both efficient and effective. However, the impact of biocontrol on target species and indirect effects from invasive species removal can be hard to predict. While monitoring the impact of invasive species removal usually involves some species-based assessment such as changes in diversity, historically dominant species or native species, these strategies do not typically provide insight into the mechanisms underlying plant community response to removal. …

Use Of Research Tradition And Design In Program Evaluation: An Explanatory Mixed Methods Study Of Practitioners’ Methodological Choices, Margaret Schultz Patel

Electronic Theses and Dissertations

The goal of this explanatory sequential mixed method study was to assess whether there were observable trends, associations, or group differences in evaluation methodology by settings and content area in published evaluations from the past ten years (quantitative), to illuminate how evaluation practitioners selected these methodologies (qualitative), and assess how emergent findings from each phase fit together or helped contextualize each other. In this study, methodology was operationalized as research tradition and method was operationalized as research design. For phase one (quantitative), a systematized ten-year review of five peer-reviewed evaluation journals was conducted and coded by journal, research tradition, research …

Probing Liquid−Liquid Phase Separation In Secondary Organic Aerosol Mimicking Solutions Using Articulated Straws, Emmaline R. Longnecker, Lucy Metz, Rebecca S. Miller, Andrew E. Berke

Chemistry: Faculty Publications

The presence or absence of liquid–liquid phase separation (LLPS) in aerosol particles containing oxidized organic species and inorganic salts affects particle morphology and influences uptake into, diffusion through, and reactivity within those particles. We report here an accessible method, similar to ice core analyses, using solutions that are relevant for both aerosol chemical systems and aqueous two-phase extraction systems and contain ammonium sulfate and one of eight alcohols (methanol, ethanol, 1-propanol, 2-propanol, 2-butaonol, 3-methyl-2-butanol, 1,2-propanediol, or 1,3-propanediol) frozen in articulated (bendable) straws to probe LLPS. For alcohols with negative octanol–water partitioning coefficient (KOW) values and O/C ratios ≥0.5, …

Dynamically Weighted Balanced Loss: Class Imbalanced Learning And Confidence Calibration Of Deep Neural Networks, K. Ruwani M. Fernando, Chris P. Tsokos

Mathematics and Statistics Faculty Publications

Imbalanced class distribution is an inherent problem in many real-world classification tasks where the minority class is the class of interest. Many conventional statistical and machine learning classification algorithms are subject to frequency bias, and learning discriminating boundaries between the minority and majority classes could be challenging. To address the class distribution imbalance in deep learning, we propose a class rebalancing strategy based on a class-balanced dynamically weighted loss function where weights are assigned based on the class frequency and predicted probability of ground-truth class. The ability of dynamic weighting scheme to self-adapt its weights depending on the prediction scores …

Structure Of Unmodified And Pyroglutamylated Amyloid Beta Peptide In Lipid Membranes, Rowan Hassan

Honors Undergraduate Theses

Alzheimer's Disease (AD) is a devastating neurodegenerative disease that is characterized by brain atrophy, neuronal and synaptic loss, cognitive decline, trouble handling activities of daily life, and ultimately leads to death. Worldwide, at least 30 million people suffer from AD, with 5.8 million suffering in the US alone. Despite extensive basic and clinical research, the underlying molecular mechanisms behind AD remain largely unknown. There are four FDA-approved compounds are used for alleviating symptoms but have no curative potency. The first potentially disease-modifying AD drug, aducanumb, was approved by FDA in June 2021. The main histopathological traits of AD are the …

Photoemission Investigation Of Topological Quantum Materials, Klauss M. Dimitri

Honors Undergraduate Theses

Topological insulators (TIs) are a class of quantum materials, which behave as insulators in the bulk, yet possess gapless spin-polarized surface states, which are robust against nonmagnetic impurities. The unique properties of TIs make them attractive not only for studying various fundamental phenomena in condensed matter and particle physics, but also as promising candidates for applications ranging from spintronics to quantum computation. Within the topological insulator realm, a great deal of focus has been placed on discovering new quantum materials, however, ideal multi-modal quantum materials have yet to be found. Here we study alpha-PdBi2, KFe2Te2, and DySb compounds including others …

Examining Everyday Literacies: An Autoethnographic Analysis Of Mundane Textualities, Kyle J. Mauter

Honors Undergraduate Theses

As a way of extending perspectives of writing and learning, this thesis explores everyday literacy activities and their role in function in shaping people's activities. Taking up an autoethnographic approach to studying the mundane literacies of everyday life, this thesis offers a fine-grained analysis of the processes and practices involved in two specific literate activities I have engaged in over the two years: creating a mixtape for a friend and streaming my participation in online video games. As key findings, the analysis of these everyday literate activities suggests that the interactions between people and social contexts figure prominently in the …

Exploring Mesoscale Structures Using Chord Occultations Of Saturn's Rings, Lamia Benyamine

Honors Undergraduate Theses

The Cassini spacecraft orbited Saturn for over 13 years and collected stellar occultations using an Ultraviolet Imaging Spectrograph (UVIS). Chord occultations were analyzed using autocorrelations at minimum ring plane radius to visualize the structure and correlation in the azimuthal direction. These particle tracking occultations cut a chord across the rings in the path of the star. By taking the autocorrelation of these chord occultations, 8 out of the 66 showed clumping within the first 3.0 km in azimuth, representing signs of a structure. Six of those occultations could be moonlets or propellers as their minimum ring plane radii are in …

Analysis And Design Of Infrared Fiber Bundles For Large Field-Of-View Thermal Imaging, Cesar A. Lopez-Zelaya

Honors Undergraduate Theses

During the DARPA SCENICC program, J. Ford, et al., demonstrated that CFBs provide a compelling route to compact, wide angle imagers. Monocentric lenses readily provide diffraction-limited images over wide field but onto a hemispherically curved image surface. They demonstrated visible CFBs can be tapered, cut and polished to relay curved images to flat sensors. We have shown that this provides a volumetric imaging efficiency a hundredfold larger than bulk optics can produce; a hundred times the resolution in the same volume or a hundred times less volume for the same resolution. Ford's work leveraged commercial fiber bundles available for the …

Analysis Of Bending Waves In Saturn's Rings, Claudia Denise Orozco Vega

Honors Undergraduate Theses

Saturn's rings are a complex, dynamic system that can provide unique insight into the structure and features of the planet and surrounding system. We use stellar occultation data of Saturn's rings collected from the Cassini Ultraviolet Imaging Spectrograph to visualize and analyze bending waves present within the rings. Analysis of the propagation of these waves gives insight into the surface mass density of the local ring region and can be used to further our understanding of ring dynamics and ring formation. Our analysis of the Mimas 7:4 bending wave estimated a surface mass density between 30 g cm^-2 and …

Fine-Grained Lower Bounds For Problems On Strings And Graphs, Gary Thomas Hoppenworth

Honors Undergraduate Theses

The motivation of this thesis is to present new lower bounds for important computational problems on strings and graphs, conditioned on plausible conjectures in theoretical computer science. These lower bounds, called conditional lower bounds, are a topic of immense interest in the field of fine-grained complexity, which aims to develop a better understanding of the hardness of problems that can be solved in polynomial time. In this thesis, we give new conditional lower bounds for four interesting computational problems: the median and center string edit distance problems, the pattern matching on labeled graphs problem, and the subtree isomorphism problem. These …

Simulating Systematic Errors In Exoplanetary Transits For The James Webb Space Telescope, David C. Wright Iii

Honors Undergraduate Theses

The James Webb Space Telescope (JWST) is a next-generation space telescope that will be capable of making transformative observations of planetary transits. As its launch date grows ever closer, it becomes imperative that astronomers have access to accurate simulations of JWST observations in order to best plan observations and devise data analysis pipelines. Unfortunately, available simulation tools do not provide the most accurate or realistic simulations, including noise and systematic errors. In this thesis, I present an open-source time-domain simulator of planetary transits that is capable of accurately modeling these effects in observations made by JWST.

Examination Of Corporate Investments In Privacy: An Event Study, Joseph Michael Squillace

CCE Theses and Dissertations

The primary objective of any corporate entity is generating as much wealth as possible. Investing financially in technology domains has historically been a successful strategy for generating increased corporate and shareholder wealth. However, investments in Information Technology (IT), Information Systems (IS) and Information Security (InfoSec) to specifically generate increased wealth must be implemented carefully.

Shareholders reacting to corporate investments perceive financial value from individual investments. The investment’s perceived value is then reflected in the corporation’s updated stock market value. IS, IT, and InfoSec investments perceived to possess positive financial value, indicating strong potential for increased wealth, are rewarded by shareholders …

Feature Selection On Permissions, Intents And Apis For Android Malware Detection, Fred Guyton

CCE Theses and Dissertations

Malicious applications pose an enormous security threat to mobile computing devices. Currently 85% of all smartphones run Android, Google’s open-source operating system, making that platform the primary threat vector for malware attacks. Android is a platform that hosts roughly 99% of known malware to date, and is the focus of most research efforts in mobile malware detection due to its open source nature. One of the main tools used in this effort is supervised machine learning. While a decade of work has made a lot of progress in detection accuracy, there is an obstacle that each stream of research is …

The Construction And Internal Validation Of A Model For The Effective Collaboration Of Distributed Agile Teams, Ernesto Custodio

CCE Theses and Dissertations

Agile approaches to software development have increased steadily over the past decade. Agile processes emphasize iterative and collaborative discovery of requirements and solutions executed by self-organizing, cross-functional teams. Software development using distributed teams, including distributed sub-teams, fully dispersed teams, and partially dispersed teams, has also increased due to benefits such as access to global talent and faster delivery, among others.

However, most Agile approaches, models, and frameworks only address the needs of colocated teams. Distributed teams come with unique challenges when it comes to effective collaboration. The goal was to construct and validate internally a model for the effective collaboration …