Digital Commons Network^™

The Ecological Applications Of Δ17O: Validating A Novel Technique For Assessing Animal Metabolism And Water Intake, Zachary Taylor Steele

Biological Sciences Theses & Dissertations

Animals obtain water via different processes such as drinking, consuming food, and through metabolic processes like at the end of the electron transport chain when atmospheric oxygen is combined with hydrogen to form ‘cytochrome oxidase water’. Assessing animal water flux and metabolism has mainly been conducted via stable isotope analysis (SIA) of biological samples using hydrogen (²H) and oxygen isotopes (¹⁶O, ¹⁷O, and ¹⁸O; Δ¹⁷O), typically using enriched isotope tracers. However, natural abundance isotope modeling offers an approach for conducting SIA of biological samples that differs because it relies on the unique, …

Why Does Multilateral Cooperation Vary Across Issue Areas? Trade Versus Foreign Direct Investment, Imran Khan

Graduate Program in International Studies Theses & Dissertations

Why does multilateral cooperation sometimes fail to emerge, even in contexts where multilateral cooperation would be more beneficial for all parties than bilateral cooperation? To explore this puzzle, a generalization of the stag-hunt game is developed. The key finding from the analysis of this “stag-elephant” hunt game is that because pursuing multilateral cooperation is a riskier strategy due to the need for a larger number of players to cooperate to achieve it, multilateral cooperation can fail to emerge even when the payoffs from multilateral cooperation substantially exceed those of bilateral cooperation. To instantiate the central argument, I have selected the …

Deep Learning In Reproducing Kernel Banach Spaces, Mingsong Yan

Mathematics & Statistics Theses & Dissertations

Deep learning has achieved immense success in the past decade. The goal of this dissertation is to understand deep learning through the framework of reproducing kernel Banach spaces (RKBSs), which were originally proposed for promoting sparse solutions. We begin by considering learning problems in a general functional setting, and establishing explicit and data-dependent representer theorems for both minimal norm interpolation (MNI) problems and regularization problems. These theorems provide a crucial foundation for the subsequent results derived for both sparse learning and deep learning. Next, we investigate the essential properties of RKBSs capable of encouraging sparsity in learning solutions. With the …

Explainable Artificial Intelligence: Methods And Evaluation, Gayane Grigoryan

Engineering Management & Systems Engineering Theses & Dissertations

A wide array of techniques within explainable artificial intelligence (XAI) have been developed to measure the importance of features in machine learning models. A notable portion of these methods draws upon principles of cooperative game theory (CGT), with the Shapley value emerging as a widely used solution concept. Despite the rising prominence of the Shapley value, other promising solutions from cooperative game theory—such as the Nucleolus, Banzhaf power index, Shapley-Shubik power index, and solutions to conflicting claims problems—have been comparatively overlooked, even though they hold significant potential. In this dissertation, multiple XAI methods based on these other CGT solutions are …

On Weighted Sequence Spaces, Gilbert D. Acheampong

Mathematics & Statistics Theses & Dissertations

The space ℓ^p,α of complex sequences a = (a₀,a₁,a₂, . . .) for which

∞

∥a∥p,α = ( Σ|ak|^p(k+1)^α)^1/p < ∞

k=0

is studied. Each such sequence can be identified with the analytic function with power series

∞

f (z) = ∑ akz^k.

k=0

In this setting, the point evaluation and the difference quotient mappings are shown to be bounded; the cases are identified in which ℓ^p,α is boundedly contained in ℓ^r,β . …

A Portable Numerical Library For The Calculation Of Multi-Dimensional Integrals, Ioannis Sakiotis

Computer Science Theses & Dissertations

Multi-dimensional numerical integration is a prevalent task in physics and other scientific fields, e.g., in the simulation of particle-beam dynamics and Bayesian parameter estimation. Scientific computing applications that simulate complex phenomena may require the solution to numerous multi-variate integrals. However, functions that have features such as sharp peaks or oscillations in high dimensional spaces, can result in an exorbitant number of computations. For many cases, convergence to accurate results in a reasonable amount of time is infeasible with existing numerical libraries. One approach towards making multi-dimensional integration viable is to parallelize existing algorithms. No commonly available algorithms or libraries exist …

Raemap: Real-Time Advanced Eye Movements Analysis Pipeline, Gavindya Jayawardena

Computer Science Theses & Dissertations

Eye-tracking offers insights into human cognition and attention allocation by capturing and interpreting eye movements. Traditionally, eye tracking research has relied on offline analysis methods, requiring post-experiment processing to derive insights from gaze data. This approach limits its applicability in contexts requiring immediate feedback and adaptive responses based on real-time gaze behaviors. Recent advancements in computing power and eye tracking technology have enabled a shift towards real-time analysis, allowing modern systems to interpret gaze data with minimal latency, facilitating integration into interactive applications and experiments. Despite these advancements, existing tools often face challenges with real-time computation of advanced gaze measures …

Use Of Cobalt(Iii) And Copper(Ii) Complexes With Thiosemicarbazone Ligands And Berberine Chloride As Anti-Cancer Agents Against Triple Negative Breast Cancer, Duaa Rashad Alajroush

Chemistry & Biochemistry Theses & Dissertations

It is a worrying fact that chemotherapeutic options for treating triple negative breast cancer are limited in nature, including the use of inorganic pharmaceuticals such as cisplatin and its analogues. It has been reported that cisplatin has undesirable side effects when used as a chemotherapeutic drug. As such, there is a need to use non-platinum-containing complexes as chemotherapeutic agents. Based on that issue, it has been reported by our research group and others that cobalt- and copper-containing complexes have shown great potential in anti-cancer properties when compared to cisplatin. In this research project, the cytotoxic effects of the following complexes: …

Adopt: An Environmentally-Friendly System For Alerting Drivers To Occluded Pedestrians Traffic, Abrar Abdulrahman Alali

Computer Science Theses & Dissertations

The emergence of sensing technologies and vehicular communications has brought significant opportunities for enhancing pedestrian safety on city streets. However, existing solutions rely on costly technologies such as computer vision and trajectory prediction to detect crossing pedestrians, while they have limits in detecting pedestrians who are occluded by parked cars. Despite the presence of collaborative perception by surrounding vehicles and infrastructure, there is a notable absence of incorporating existing parked cars themselves due to their insufficiency in detecting pedestrians and communicating with other cars while they are turned off. Furthermore, accommodating pedestrians on streets has been linked to an additional …

A Microservices Approach To Electroencephalography Research In The Public Cloud, Bathsheba Farrow

Computer Science Theses & Dissertations

The rich information content of the brain is embedded in electroencephalography (EEG) data that instantaneously measures its electrophysiological activity. Expansion of EEG data usage for health risk predictions and other applications requires reliable and consistent methods for extracting features from raw signals. However, the intricate nature of EEG signal data analysis is further complicated by the magnitude of variability in current research practices, including data preprocessing strategies. The heavy reliance on antiquated, stove-piped applications and pipelines also highlights a need for improved solutions that enable efficient, distributed preprocessing of large EEG data collections.

To address these challenges, we propose a …

Contributions To Nonparametric Testing In Clustered Data, Hasika Kalani Wickrama Senevirathne

Mathematics & Statistics Theses & Dissertations

Clustered data refers to a specific kind of correlated data where units within the same cluster are correlated while units from different clusters are independent. The number of units in each cluster, known as the cluster size, can be associated with the cluster’s outcome. This is known as the informative cluster size (ICS) and affects the inference drawn from clustered data. Recently, a hypothesis testing method has been developed to detect the presence of ICS. However, considering ICS alone may not be sufficient when comparing outcomes across multiple groups of units within clustered data. The size of a group within …

Measurement Of The Photoproduction Cross-Section Of F1(1285) In The Exclusive Reactions Γp → P′K∓KSΠ± At 7.5 < Eγ < 11.5 Gev With Gluex At Jefferson Lab, Tyler Viducic

Physics Theses & Dissertations

The f₁(1285) meson is commonly understood to belong to the axial-vector nonet as the low-mass isoscalar partner to the f₁(1420) but has been suggested as a candidate for a KK^∗+c.c molecule. A nearly mass-degenerate 0 ⁻⁺ state has been observed in πp scattering that calls into question the established branching ratios of the f₁(1285) decays. Recently, the differential cross-section for the photoproduction of f₁(1285) was measured by the CLAS experiment and the results disagreed with theoretical predictions. Additionally, the CLAS experiment did not observe a mass-degenerate 0⁻⁺ state. …

Coherent Backscattering Under Conditions Of Electromagnetically Induced Transparency In Ultracold Rubidium, Joshua D. Carter

Physics Theses & Dissertations

This dissertation presents experimental results of coherent backscattering of light in an ultracold ensemble of rubidium atoms confined in a magneto optical trap under conditions of electromagnetically induced transparency (EIT) in a cascade-type system. Electromagnetically induced transparency was investigated experimentally in both a counterpropagating and orthogonal laser geometry and compared to theory. The experimental results were largely in good agreement with theory. Coherent backscattering was then measured with and without an EIT control field present to investigate the modification, if any, that EIT has on the enhancement of the coherent backscattering cone. The results indicated that the electromagnetically induced transparency …

Who Wrote The Scientific News? Improving The Discernibility Of Llms To Human-Written Scientific News, Dominik Soós

Computer Science Theses & Dissertations

Large Language Models (LLMs) have rapidly advanced the field of Natural Language Processing and become powerful tools for generating and evaluating scientific text. Although LLMs have demonstrated promising as evaluators for certain text generation tasks, there is still a gap until they are used as reliable text evaluators for general purposes. In this thesis project, I attempted to fill this gap by examining the discernibility of LLMs from human-written and LLM-generated scientific news. This research demonstrated that although it was relatively straightforward for humans to discern scientific news written by humans from scientific news generated by GPT-3.5 using basic prompts, …

Hydrologic Modeling Of The Lower Chesapeake Bay Watershed Using Hecc-Hms With Implications For Future Coupled Coastal Modeling, Christopher Leonard Frost

Civil & Environmental Engineering Theses & Dissertations

This study explores the hydrological methodology for modeling a coastal watershed basin using the US Army Corps of Engineers hydrologic software, HEC-HMS with an objective of being able to create riverine boundary conditions that could be applied to a coupled compound flood model. Compound flooding is defined as high water inundation event that occurs due to the simultaneous occurrence of multiple flooding drivers. The Atlantic Seaboard and the Gulf of Mexico regions of the United States account for most of the compound events observed in the United States with a higher occurrence caused by hurricanes from July to November. In …

Surfacing Text Changes In Archived Webpages, Lesley Frew

Computer Science Theses & Dissertations

Webpages change over time, and web archives hold copies of historical versions of webpages. Users of web archives, such as journalists, want to find and view changes on webpages over time. However, the current search interfaces for web archives do not adequately support this task. For the web archives that include a full-text search feature, multiple versions of the same webpage that match the search query are shown individually without enumerating changes, or are grouped together in a way that hides changes. We present a change text search engine that allows users to find changes in webpages. We describe the …

A Kinematic Analysis Of The Shoulder During The Volleyball Attack Using Euler And Helical Axis Methods, Victoria Jolliff

Biomedical Engineering Theses & Dissertations

The shoulder is a complex joint with a wide range of motion, including flexion, extension, abduction, adduction, and internal and external rotation. In volleyball, repetitive overhand movements can cause shoulder overuse injuries. The primary offensive move, the attack, involves the approach, arm cocking, arm acceleration, and follow-through phases. Motion capture analysis and techniques like calculating Euler angles and rotation about a mean helical axis can evaluate shoulder movements. This study aimed to calculate shoulder movements during each phase of the volleyball attack using the Euler angle YXY sequence and the helical axis method. Different attack types, such as cross-court and …

Streaminghub - A Realtime Biosignal Processing Framework For Lab Scale Experimentation, Yasith Jayawardana

Computer Science Theses & Dissertations

In human subjects research, biosignals such as eye movements, heart rate, and brain activity, are often collected and analyzed to find patterns with tangible real-world implications. Modern advancements in technology have sparked interest towards analyzing biosignals in realtime. When developing such algorithms, one may expect to find free, open-source tools that provide easy access to live, recorded, and simulated data streams. Yet, biosignal interfaces are often vendor-specific, making cross-vendor biosignal streaming non-trivial. Likewise, reading biosignal datasets is also non-trivial, as their content may be arranged quite differently.

To combat this divide, we provide the scientific community with a realtime biosignal …

Harnessing Social Media For Disaster Response: Intelligent Identification Of Reliable Rescue Requests During Hurricanes, Wael Khallouli

Engineering Management & Systems Engineering Theses & Dissertations

Hurricanes pose a significant threat to both human lives and infrastructure. Decision-makers face substantial challenges during such events, as they must act quickly to address victims’ needs. Social media platforms provide a valuable source for quick and real-time information. Recent hurricane events have shown that people turn to social media to call for help when official communication channels, such as 911, are overwhelmed. However, extracting actionable information from the massive number of messages posted on social media is challenging. Furthermore, verifying social media messages posted by the public is a critical concern for disaster response practitioners, making them hesitant to …

Study Of Atypical Alarmone Synthesis In Clostridioides Difficile, Declan Nathaniel Butler

Chemistry & Biochemistry Theses & Dissertations

Clostridioides difficile is a Gram-positive anaerobic bacterium that causes infections in humans that costs healthcare systems billions per year. C. difficile infection has high rates of recurrence due to multiple antibiotic resistance. When bacteria are in stressful environments, they produce hyperphosphorylated guanosine ribonucleotide signaling molecules called alarmones. The accumulation of alarmones activates the stringent response (SR), in which bacterial cells induce transcription of stress survival genes to delay growth and replication. The C. difficile SR is regulated by enzymatic activity of a bifunctional synthetase/hydrolase, RelA/SpoT homolog (RSH), and a monofunctional small alarmone synthetase (RelQ). Additionally, the SR is potentially regulated …

Parallel-In-Time Implicit Schemes For Nonlinear Pdes, Subhash Paudel

Mathematics & Statistics Theses & Dissertations

An accurate prediction of unsteady physical phenomena arising in various applications (e.g., rotorcraft and turbomachinery flows, fluid-structure interaction, maneuvering flight conditions, etc.) requires a very large number of time steps, thus considerably increasing the total computational time, because conventional time integrators are inherently sequential. Parallel-in-time methods offer a promising direction for drastically reducing the computational time and achieving such scalability that is required for solving these unsteady problems on modern supercomputers with hundreds of thousands of computing cores. The parallel performance of existing parallel-in-time algorithms for nonlinear equations especially of the hyperbolic or mixed type is far from being satisfactory. …

Hydrogen Sulfide As A Strong Ligand Affecting Trace Metal Cycling In The Pacific And Southern Oceans, Nicole R. Buckley

OES Theses and Dissertations

Historically, hydrogen sulfide was considered unimportant in the open ocean since it has primarily been associated with anoxic environments. Yet, in the late 1980s it was suggested that this sulfur gas is also being produced in the oxic, surface ocean through the hydrolysis of carbonyl sulfide (OCS). Since then, several studies have demonstrated that hydrogen sulfide is indeed found in oxic seawater at pico- to nanomolar concentrations due not only to carbonyl sulfide hydrolysis, but also assimilatory sulfate reduction by phytoplankton. Hydrogen sulfide’s importance in seawater is largely due to its high metal-ligand stability constants allowing it to affect the …

Synthesis And Characterization Of Cobalt-Based Complexes And Metal-Organic Frameworks For Hydrogen Evolution Catalysis Under Acidic Conditions, Elizabeth A. Tonsel-White

Chemistry & Biochemistry Theses & Dissertations

The synthesis of two cobalt(II) complexes: the novel complex [Co(phen)₃]₂[Co(pytc)₂]•16.25H₂O 1 and the previously reported [Co(bpy)₃](OH)₂•7H₂O 2, along with a cobalt(II/III)-containing MOF, Co-PPF2, previously reported as well, was achieved. These complexes were characterized by elemental analysis, X-ray crystallography, microscopy, conductivity measurements, TGA, SEM, CV , and UV-visible , and FTIR spectroscopies. From the CV scan rates, diffusion coefficients for complexes 1 and 2 were determined to be 1.0 × 10⁻⁶ cm² s⁻¹ and 4.8 × 10⁻⁷ cm² s⁻¹. Electrocatalytic studies with complexes 1 and 2 revealed insights into the mechanistic aspects of …

Mesostructure Reconstruction Of Prepreg Platelet Molded Composite With Artificial Intelligence, Richard Larson

Mechanical & Aerospace Engineering Theses & Dissertations

Prepreg platelet molded composites (PPMC) are long, discontinuous fiber reinforced polymer materials. PPMC are an important subcategory of composite materials as they are processible into geometrically complex structures and can be produced via high-throughput manufacturing processes, however they have higher stiffness and strength as compared to traditional discontinuous fiber reinforced polymers. However, there is inherent randomness in the structure of PPMCs and as such, PPMC parts frequently require per part testing that is cost prohibitive.

Herein, a method using artificial intelligence is proposed as a more cost-effective method of inspecting PPMC parts. Different artificial intelligence (AI) architectures are explored to …

Privacy-Preserving Deep Learning Framework For Iot Malware Detection, Sabbir Ahmed Khan

Computer Science Theses & Dissertations

Cyberattacks on IoT devices are accelerating at an unprecedented rate, largely driven by IoT malware activities. The IoT malware attacks typically comprise three stages: intrusion, infection, and monetization. Existing IoT malware detection methods fail to identify malicious activities at the intrusion and infection stages and thus cannot stop potential attacks timely. In our research, we have leveraged power side-channel information as input to our deep learning model to identify malware at early stages of intrusion on IoT devices. But, deploying a resource-intensive deep learning model on highly resource-constrained IoT devices is a significant challenge. Consequently, utilizing a Machine Learning as …

Investigation Of Cooperative Subradiance In Dense Ultracold Rubidium Ensembles, Brent Michael Jones

Physics Theses & Dissertations

This dissertation presents results of an experimental investigation of the time resolved fluorescence from a cold and dense ensemble of ⁸⁷Rb atoms after the sample is illuminated by a short probe pulse. The goal of the experiment was to investigate cooperative subradiant behavior, characterized by a much longer decay time compared to the natural lifetime, induced in an off resonant probe regime. Such long lived states, if controllable, would provide a means to store quantum information. The samples were initially created in a magnetooptical trap before atoms were loaded into a far off resonance trap to achieve atomic densities …

Safe And Efficient Operation Of Mobile Robots In Indoor Environments: A User-Centric Shared Control System With High-Level Navigation Capabilities, Ahmet Saglam

Electrical & Computer Engineering Theses & Dissertations

Hospitalization and isolation can be a traumatic experience for immunocompromised children, especially because they are separated from their families and friends. Social robots have been proposed as a way to improve the quality of care for children hospitalized in isolation by providing alternative means of social interaction and support. Remote control of such robots in a hospital setting, particularly where safety is a major concern, can be a daunting task for young patients.

This dissertation introduces a multilevel shared control system for mobile robots, specifically companion robots in hospital-like indoor spaces. The system integrates user inputs with algorithmic semi-autonomous control …

Zero Dynamics Attacks On Unknown Bilinear Systems: Vulnerability And Detection, Mohammad Aminul Haq

Electrical & Computer Engineering Theses & Dissertations

Critical infrastructure requires a safe and secure operating environment because of its significant impact on society. Its large-scale size and distributed sensors and actuators make it vulnerable to cyber-physical attacks. A zero dynamics attack is a type of cyber-physical attack where an adversary keeps the output of the target constant (classically zero), while forcing some of the internal states to deviate from their nominal values. Most of the existing work in the literature assumes the system dynamics are linear and available to an adversary. The first goal of this dissertation is to show that an adversary can successfully execute a …

Associations Between Combat Exposure, Moral Injury, And Suicidality Among U.S. Military Members: The Moderating Impact Of Positive Rumination, Jeffrey M. Gabelmann

Psychology Theses & Dissertations

Numerous studies have documented the risk for suicide among recent-era veterans with combat experience. Recently, moral injury has emerged as a possible contributor to suicidality in veterans. To that end, no study has approached the combat exposure-moral injury-suicidality link with a focus grounded in positive psychology. Specifically, the present study explored whether positive rumination, or the reflection on positive emotions and moods, may buffer the deleterious effects of potentially traumatic experiences in warzones on moral injury and suicidality. This study was a secondary analysis of 250 current or former U.S. military members (M_age = 33.3 years) who had …

A Review Of Secondary Technology Education Teacher Needs In Virginia, M. Kathleen Ferguson

Educational Leadership & Workforce Development Theses & Dissertations

Technology education teachers can have varied pre-service training experiences, thus their needs for classroom support may vary greatly. Perkins V requires evidence-based research to justify the use of funding for professional development. This researcher sought to support Virginia’s secondary technology education teachers, professional organizations, and the Virginia Department of Education’s Technology Education Specialist by providing research to determine professional development needs. This three-phase qualitative study used a survey, documents review, and focus groups to triangulate data to provide information about the research questions. The research questions focused on teachers’ educational background, technology program goals, and issues specific to secondary technology …