Digital Commons Network^™

Identification And Modeling Social Media Influence Pathways: A Characterization Of A Disinformation Campaign Using The Flooding-The-Zone Strategy Via Transfer Entropy, Jasser Jasser

Electronic Theses and Dissertations, 2020-2023

The internet has made it easy for narratives to spread quickly and widely without regard for accuracy or the harm they may cause to society. Unfortunately, this has led to the rise of bad actors who use fake and misleading articles to spread harmful misinformation. These actors flood the information space with low-quality articles in an effort to disrupt opposing narratives, sow confusion, and discourage the pursuit of truth. In societies that prioritize free speech, maintaining control over the information space remains a persistent challenge. Achieving this requires strategic planning to protect the dissemination of information in ways that promote …

Active Photonic Integrated Devices And Circuits On Thin-Film Lithium Niobate Platform, Ehsan Ordouie

Electronic Theses and Dissertations, 2020-2023

This thesis delves into innovative active photonic integrated devices and circuits on the thin-film lithium niobate (TFLN) platform, focusing on their applications and potential future advancements. We introduce a new family of electrooptic modulators (EOMs), the Four-Phase Electrooptic Modulators (FEOMs), which are fabricated using the TFLN platform. These devices effectively mitigate bandwidth and dynamic-range constraints in optical communication systems by reducing dispersion penalties and common-mode noises. Their functionality is demonstrated in a photonic time-stretch system. A dual-polarization variant further exemplifies the mitigation of both dispersion penalties and common-mode noises in long-haul communication links, marking significant strides towards the practical implementation …

Clustering Of Diverse Multiplex Networks, Yaxuan Wang

Electronic Theses and Dissertations, 2020-2023

This dissertation introduces the DIverse MultiPLEx Generalized Dot Product Graph (DIMPLE-GDPG) network model where all layers of the network have the same collection of nodes and follow the Generalized Dot Product Graph (GDPG) model. In addition, all layers can be partitioned into groups such that the layers in the same group are embedded in the same ambient subspace but otherwise all matrices of connection probabilities can be different. In common particular cases, where layers of the network follow the Stochastic Block Model (SBM) and Degree Corrected Block Model (DCBM), this setting implies that the groups of layers have common community …

Investigating Shallow Neural Networks For Orbit Propagation Deployed On Spaceflight-Like Hardware, Hunter Quebedeaux

Graduate Thesis and Dissertation 2023-2024

Orbit propagation is the backbone of many problems in the space domain, such as uncertainty quantification, trajectory optimization, and guidance, navigation, and control of on orbit vehicles. Many of these techniques can rely on millions of orbit propagations, slowing computation, especially evident on low-powered satellite hardware. Past research has relied on the use of lookup tables or data streaming to enable on orbit solutions. These solutions prove inaccurate or ineffective when communication is interrupted. In this work, we introduce the use of physics-informed neural networks (PINNs) for orbit propagation to achieve fast and accurate on-board solutions, accelerated by GPU hardware …

Thermal Management Strategies For Hypersonic Flight: Supercritical Co2 Jet Impingement Cooling Investigation For Leading Edge, Manoj Prabakar Sargunaraj

Graduate Thesis and Dissertation 2023-2024

This study addresses the critical need for effective thermal management in hypersonic vehicles facing intense heat at their leading edge due to high enthalpy flow. The objective is to propose an active impingement cooling system that ensures the structural stability and performance of these vehicles. This dissertation presents an in-depth exploration of the numerical simulations conducted on the hypersonic leading edge, focusing on a 3mm radius with active cooling utilizing supercritical carbon dioxide (sCO2) as the coolant. The research incorporates conjugate simulations that merge external hypersonic flow and sCO2 active cooling. Utilizing a thermodynamic non-equilibrium two-temperature model and various chemical …

Control Of The Spar-Buoy Based Wind Turbine Floating Platform Through Mooring Line Actuation, Tajnuba Hasan

Graduate Thesis and Dissertation 2023-2024

This thesis presents an innovative approach to enhance the stability of floating offshore wind turbine (FOWT) platform through mooring actuation. First, an OC3- Hywind spar-buoy floating platform is modeled utilizing the Control-oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS) with a specific focus on predicting hydrodynamic and mooring line loads while intentionally excluding consideration of aerodynamic forces. The accuracy of this model is validated against the industry standard OpenFAST simulator through various test cases. The central objective of this study revolves around achieving robust stabilization of the spar buoy platform, primarily focusing on X-Z symmetric planar motions, including surge, pitch, …

Development Of Regolith Simulants Of Lunar Permanently Shadowed Regions And Jupiter Trojan Asteroids, Karlis Slumba

Electronic Theses and Dissertations, 2020-2023

Every scientific experiment or innovation goes through a phase of testing equipment. This is not only true for experiments in the laboratory, but also very relevant for experiments on other planetary bodies. In order to test tools and robotic equipment that are destined for another planet, moon, asteroid or comet, it is necessary to simulate the regolith environment on that surface. In this thesis we have provided an overview of two methods for regolith simulant development. In one approach we made simulants in different compositions to find the best spectral fit to Jupiter Trojan asteroids. At visible to near-infrared (VNIR) …

Ocean Vector Wind Measurement Potential From The Global Precipitation Measurement Mission Using A Combined Active And Passive Algorithm, Alamgir Hossan

Electronic Theses and Dissertations, 2020-2023

Ocean surface vector wind (OVW) is an essential parameter for understanding the physics and dynamics of the ocean-atmosphere system, thereby improving weather forecasting and climate studies. Satellite scatterometers, synthetic aperture radars, and polarimetric microwave radiometers have provided almost global coverage of ocean surface vector wind for the last four decades. Nonetheless, a consistent and uninterrupted long-time data record with the capability of resolving sub-diurnal variability has remained a critical challenge over the years. The Global Precipitation Measurement Mission (GPM) is a satellite mission designed to provide space-based precipitation information on a global scale with complete diurnal sampling. This dissertation presents …

Evolutionary History And Adaptation To Salinity In American Alligators, John Konvalina

Electronic Theses and Dissertations, 2020-2023

Stressful environments can commonly be found at the edge of a species range and may be a driver for adaption in suboptimal environments. Furthermore, the edge of a species' range can expand and contract over time, resulting in multiple independent invasions of the same stressful habitat. Elucidating population genetic structure and demographic history can aid in determining the which geologic factors impact range distributions and when climatic changes occurred driving genetic patterns observed in contemporary populations. Moreover, populations at the edge of the species range may adapt to the stressful environments that occur at the range edge and exhibit genetic …

Predicting Heart Disease Using Tree-Based Model, Emil Agbemade

Data Science and Data Mining

The paper presents a study on the use of machine learning algorithms for the prediction of heart disease, which is the leading cause of death worldwide. The study focuses on the use of decision tree algorithms, which have the advantage of considering a large number of risk factors. The heart disease data set was obtained from the UCI Machine Learning Repository and was analyzed using a decision tree classifier. The data set had 6 missing data points, which were deleted, leaving 279 instances for analysis. One-hot-encoding was performed on categorical variables with more than two responses. The decision tree classifier …

Machine Learning-Based Approaches For Predicting The Critical Temperature Of Superconductor, Pradip Dhakal

Data Science and Data Mining

This paper focuses on utilizing multiple linear regression, lasso regression, and extreme gradient boosting algorithms to predict the critical temperature of the superconductor. The model will be evaluated using the mean square error and adjusted R-squared values, and the best model will be recommended for future work related to this study.

Variable Selection Using Lasso And Elastic Net Regression On High Dimensional Genetic Architecture Data Of Maize Flowering Time, Pradip Dhakal

Data Science and Data Mining

Variable selection is one of the key components in the machine learning area. This method reduces the unwanted and redundant predictors in the model, which prevents the overfitting situation. Since the model contains few significant predictors, the model is less likely to learn the trend from the noise. Further, the time to train the model reduces when we have only a few valuable variables.

Silent Agony: Automated Detection Of Ethnic And Religious Cyberbullying Using Machine Learning, Emil Agbemade

Data Science and Data Mining

The use of electronic mobile devices, social media, and networking websites has increased tremendously in recent years. Despite the advantages of these systems, such as exchanging ideas and information, being sociable, and providing entertainment, users may encounter adverse behaviors like toxicity, bullying, extremism, and cruelty. The prevalence of such behaviors has grown significantly in cyberspace, posing a threat to individuals and communities. To address this issue, there is a high demand for automated cyberbullying detection systems. Machine learning algorithms have been widely used to build such systems by classifying and detecting cyberbullying. In this study, we employed popular machine learning …

Homogeneity Test On Error Rates From Ordinal Scores And Application To Forensic Science, Ngoc Ty Nguyen

Graduate Thesis and Dissertation 2023-2024

The Receiver Operating Characteristic (ROC) curve is used to measure the classification accuracy of tests that yield ordinal or continuous scores. Ordinal scores are common in medical imaging studies and, more recently, in black-box studies on forensic identification accuracy (Phillips et al., 2018). To assess the accuracy of radiologists in medical imaging studies or the accuracy of forensic examiners in biometric studies, one needs to estimate the ROC curves from the ordinal scores and account for the covariates related to the radiologists or forensic examiners. In this thesis, we propose a homogeneity test to compare the performance of raters. We …

Weierstrass Vertices On Finite Graphs, Abrianna L. Gill

Honors Undergraduate Theses

The intent of this thesis is to explore whether any patterns emerge among families or through graph operations regarding the appearance of Weierstrass vertices on graphs. Currently, patterns have been identified and proven on cycles, complete graphs, complete bipartite graphs, and the house and house-x graphs. A Python program developed as part of this thesis to perform the algorithms used in this analysis confirms these findings. This program also revealed a pattern: if v is a Weierstrass vertex, then the vertex v* added to the graph as a pendant vertex to v is also a Weierstrass vertex. The converse is …

Using Wastewater-Based Epidemiology To Study Chlamydia Occurrence On A College Campus, Jessie E. Chin Quee

Honors Undergraduate Theses

Chlamydia is a sexually transmitted disease caused by Chlamydia trachomatis, commonly affecting sexually active college-aged adults. Presently, opportunistic testing, self-testing, and information campaigns are methods to screen vulnerable populations and raise awareness about chlamydia. Chlamydia remains underdiagnosed and undertested due to a lack of participation by individuals who may have been exposed to it. Wastewater-based epidemiology is a rising biomonitoring tool that detects the presence of disease- and drug-specific biomarkers in a community's wastewater. In this study, wastewater-based epidemiology was used to detect the presence of C. trachomatis on the University of Central Florida campus. Wastewater samples were collected …

A Numerical Analysis Of Shock Angles From Inward Turning Axisymmetric Flows, William L. Hilal

Honors Undergraduate Theses

Detonation-based propulsion systems are known for their high efficiency and energy release when compared to deflagrative systems, making them an ideal candidate in hypersonic propulsion applications. One such engine is the Oblique Detonation Wave (ODW) engine, which has a similar architecture to traditional scramjets but shortens the combustor and isolator to an anchored ODW after fuel injection.

Previous research has focused on using a two-dimensional wedge to induce an ODW while limiting total losses through the combustor. In this configuration, a two-dimensional wedge-based architecture entails a rectangular duct, limiting potential inlet design and increasing overall skin friction. However, an inward-turning …

Understanding The Pressure-Sinkage Relationship For Simulated Lunar Regolith And Implications On Bearing Capacity And Trafficability, Catherine A. Millwater

Honors Undergraduate Theses

The intent of this thesis is to explore the pressure-sinkage relationship for simulated lunar regolith (simulant). The simulants used in this experiment emulate the lunar highlands (LHS-1) and the lunar mare (LMS-1). The ultimate ability of a terrain or regolith to support a load without shear failure is vital to the planning and construction of permanent infrastructure. This relationship can be measured by applying a normal load to the regolith until shear failure, from which allowable and ultimate bearing capacity can be deduced. An understanding of the pressure-sinkage of lighter loads on the higher ‘fluffy' layer of regolith is of …

The Significance Of Art Education: Creating A Digital Classroom Advocating Art Education, Keri K. O'Connell

Honors Undergraduate Theses

Art programs have always been essential to education; they have provided students with a safe place to express themselves and make risk-free choices. However, due to budget cuts to the public school systems, art education is in jeopardy. The impact of the budget cuts on art education is widespread and has reduced student access to the arts and lowered the quality of the art education programs within our public school system. Schools can only provide students with the necessary resources, such as art supplies, technology, and professional development for art educators, with adequate funding. When schools are not receiving adequate …

Spinoza's Cosmopsychism: The Multifaceted Mind Of Nature, Audrey N. Perryman

Honors Undergraduate Theses

In my thesis, I will argue that while at first glance Spinoza's system seems to conflict with itself and provide an explanation of the mind that can be more confusing than helpful, its aspect of panpsychism provides a sort of lifeline for understanding. Not only does Spinoza's cosmopsychism make his system cohesive, but it can also be independently motivated by ideas that are compatible with the more contemporary intuitions in philosophy of mind. I will explore the specific nature of this universal mentality, how Spinoza's particular genre of panpsychism relates to other theories of panpsychism, and how his conception of …

Granular Jamming: Stiffness Vs Pressure And Organ Palpation Devices, Christopher H. Quach

Honors Undergraduate Theses

The intent of this thesis it to find a correlation between the stiffness of granular jammed particles and the pressure of the vacuum initiating the jamming force. Currently, granular jamming is being used to create palpation simulators for physicians to practice feeling the variety of stiffnesses of organs when healthy or ill. Because granular jamming allows for variable stiffness of any shape, it is an apt phenomenon to simulate the change of rigidity organs like the liver undergoes when diseased. For physicians to correctly identify how stiff the organ must be when using these palpation simulators, there needs to be …

The Effects Of Head-Centric Rest Frames On Egocentric Distance Perception In Virtual Reality, Yahya Hmaiti

Honors Undergraduate Theses

It has been shown through several research investigations that users tend to underestimate distances in virtual reality (VR). Virtual objects that appear close to users wearing a Head-mounted display (HMD) might be located at a farther distance in reality. This discrepancy between the actual distance and the distance observed by users in VR was found to hinder users from benefiting from the full in-VR immersive experience, and several efforts have been directed toward finding the causes and developing tools that mitigate this phenomenon. One hypothesis that stands out in the field of spatial perception is the rest frame hypothesis (RFH), …

Revisiting The Vigilance Taxonomy: Are Findings Consistent In A Remote Environment?, Grace E. Waldfogle

Graduate Thesis and Dissertation 2023-2024

Previous research has highlighted key taxonomic factors that have been found to influence human performance on vigilance tasks. However, previous literature has focused on research conducted in laboratory settings but has not examined vigilance tasks in remote environments. The present dissertation addresses this gap in the literature by examining human performance on a remote vigilance task, as well as workload and stress associated with the task. Qualitative data were collected to further understand the environment and distractions that participants experienced. Across three experiments, 372 participants were asked to complete a vigilance task and answer surveys pertaining to stress, workload, and …

Adversarial Attacks, Coarse Robustness, And Dataless Neural Networks: Novel Techniques For Improved Classification And Combinatorial Optimization, Ismail Alkhouri

Electronic Theses and Dissertations, 2020-2023

Neural networks (NN) have become a central component in most machine learning systems. However, studies have shown that these models are not robust against adversarial attacks. As such, in this dissertation, we explore four directions. In the first direction, we investigate adversarial attacks on two hierarchical classification (HC) models: the Flat HC (FHC), and the Top-Down HC (TDHC). In particular, we formulate attacks against these models by using convex programming. Through experimental results, it is shown that FHCs are more robust than TDHCs. Second, we formalize a new notion of coarse robustness that is defined with respect to a specified …

Bench- And Pilot-Scale Corrosion Control Inhibitor Effectiveness Studies For A Community's Blended Surficial And Brackish Groundwater Supply, Paula Campesino

Electronic Theses and Dissertations, 2020-2023

The United States Environmental Protection Agency regulates the lead and copper content of a public water system's finished water at the consumer's tap, through the Safe Drinking Water Act's Lead and Copper Rule (LCR), promulgated in 1991. This rule was recently changed through the LCR Revisions (LCRR), that took effect in 2021. The more stringent requirements of the LCRR motivated the City of Sarasota, Florida (City), to work with the University of Central Florida (UCF) on a study of the municipality's finished water corrosivity. Initially, this evaluation investigated the City's existing finished water corrosivity using linear polarization resistance (LPR) measurements …

The Development Of Computational Models For Melting-Solidification Applications Using The Volume-Of-Fluid Method, Brendon Cavainolo

Electronic Theses and Dissertations, 2020-2023

Fluids-related issues in the Aerospace industry are often multiphase in scope. Numerical modeling, such as computational fluid dynamics, is used to describe these problems, as they are difficult or impossible to describe analytically. This research uses computational fluid dynamics to describe multiphase problems related to melting-solidification and particle impingement. Firstly, a numerical model was established that uses the Volume-of-Fluid method to resolve a melting/solidifying particle. This model was verified against experiments and simplified analytical models, and a mesh independence study was done to ensure the results were independent of the mesh sizing. Next, the model was applied to two separate …

Understanding, Modeling, And Simulating The Discrepancy Between Intended And Perceived Image Appearance On Optical See-Through Augmented Reality Displays, Austin Erickson

Electronic Theses and Dissertations, 2020-2023

Augmented reality (AR) displays are transitioning from being primarily used in research and development settings, to being used by the general public. With this transition, these displays will be used by more people, in many different environments, and in many different contexts. Like other displays, the user's perception of virtual imagery is influenced by the characteristics of the user's environment, creating a discrepancy between the intended appearance and the perceived appearance of virtual imagery shown on the display. However, this problem is much more apparent for optical see-through AR displays, such as the HoloLens. For these displays, imagery is superimposed …

High-Dynamic-Range And High-Efficiency Near-Eye Display Systems, En-Lin Hsiang

Electronic Theses and Dissertations, 2020-2023

Near-eye display systems, which project digital information directly into the human visual system, are expected to revolutionize the interface between digital information and physical world. However, the image quality of most near-eye displays is still far inferior to that of direct-view displays. Both light engine and imaging optics of near-eye display systems play important roles to the degraded image quality. In addition, near-eye displays also suffer from a relatively low optical efficiency, which severely limits the device operation time. Such an efficiency loss originates from both light engines and projection processes. This dissertation is devoted to addressing these two critical …

Design And Control Of A Dual Active Bridge Converter For Electric Vehicle (Ev) And Photovoltaic (Pv) Applications, Md Safayatullah

Electronic Theses and Dissertations, 2020-2023

With the growing concerns of climate change due to fossil fuel-based electricity generation, solar integration to the grid is swiftly increasing. However, the intermittency of solar power is a major obstacle to harness it efficiently. Energy storage system (ESS) with its declining price over the last few years is a viable solution to address this issue. Another source of greenhouse gas emission is fossil fuel-based transportation system which is likely to be replaced by electric vehicles (EVs) in near future. To match the driving range of EVs with the internal combustion engine-based vehicle, fast and extreme fast charging infrastructure in …

An Examination Of A Decade Of K-5 Mathematics Standards In The United States, Ashley Schmidt

Electronic Theses and Dissertations, 2020-2023

This qualitative content analysis research study examined changes made to K-5 state mathematics standards across the United States from 2012 to 2022. This study aimed to answer the research question: In what ways, if any, do K-5 state mathematics standards differ from the CCSSM? This was accomplished through four additional sub questions which include: (1) In what ways, if any, do K-5 state mathematics student process and practice standards differ from the CCSSM? (2) In what ways, if any, do K-5 state mathematics standards content domains differ from the CCSSM? (3) In what ways, if any, do states describe how …