Digital Commons Network^™

High-Efficieny Ultrafast Mid-Infrared Source For Strong Field Science, Fangjie Zhou

Electronic Theses and Dissertations, 2020-2023

The potential of high-energy sources within the mid-infrared region (3-8 μm) has garnered significant attention for diverse research and industrial applications. Millijoule pulses extending beyond 3 μm can facilitate the production of x-rays with photon energies in the keV range through high harmonic generation (HHG). These high-energy x-ray pulses enable the characterization of electron dynamics within molecules and condensed matter materials. Additionally, the atmospheric transmission window between 3-5 μm allows lasers within this spectral range to deliver energy efficiently to distant targets via optical filaments without divergence, highlighting promising prospects for defense applications. In contrast to laser amplifiers, which are …

Understanding Outgroup Aversion Effects On Innovation Adoption And Polarization In Network Environments, Bruce G. Miller

Graduate Thesis and Dissertation 2023-2024

Individuals' decisions to adopt an innovation can be influenced by the group identity of previous adopters or non-adopters in their social network. Previous research in innovation diffusion considered initial innovators and word-of-mouth imitator effects using analytical models. Simulations and agent-based models have been developed to address the heterogeneity of decision makers and the non-linearity of the process. A further refinement modeled adoption based on networks of social relationships between potential decision makers, analogous to the spread of disease on networks. In addition, adoption or non-adoption of some innovations has been characterized as a means of signaling identification with or aversion …

Orange Groves And Timber Stands: The Shaping Of Marjorie Kinnan Rawlings As Woman And Writer, Ginger Clark

The Marjorie Kinnan Rawlings Journal of Florida Literature

No abstract provided.

Optical Design Study Of A High-Resolution Spectrograph Utilizing Photonic Lanterns For A Large Fiber Array Telescope, Richard D'Alo

Graduate Thesis and Dissertation 2023-2024

Large area fiber array telescopes are a relatively modern development in the long history of telescope design and effectively create a single large equivalent aperture by combining many smaller unit telescopes at a fraction of the cost. In this study a spectrograph optical design is demonstrated that utilizes photonic lanterns in the input fiber feed for the Large Fiber Array Spectroscopic Telescope (LFAST) design concept, where photonic lanterns provide a simplified approach to the fiber feed originally proposed for LFAST. Conservation of etendue is applied to derive the relationship between slit size and photonic lantern ratio, and classical echelle spectrograph …

Host Cell Responses Modulate Oncolytic Viral Treatment Of Neuroblastoma Cells, Kritika Kedarinath

Electronic Theses and Dissertations, 2020-2023

Neuroblastoma is an aggressive pediatric cancer that is poorly responsive to traditional cancer therapies. Oncolytic viral (OV) vectors such as Zika virus (ZIKV) and Parainfluenza virus type 5 (P/V virus) are promising neuroblastoma therapeutics, but the role of innate immune responses in the effectiveness of OV killing is not well understood. Previous studies showed the neuroblastoma cell line SK-N-AS (expressing low CD24) had low permissivity for ZIKV infection, and this restriction was relieved by ectopic CD24 expression (CD24-high cells). Compared to permissive CD24-high cells, the non-permissive CD24-low cells had elevated basal levels of IRF-1, NF?B and phosphorylated STAT1; these cells …

A Developmental Investigation Of Separation And Analysis Of Molecular Mass 302 Da Polyaromatic Hydrocarbons Using High Performance Liquid Chromatography And Chiral Stationary Phase, James Janesko

Electronic Theses and Dissertations, 2020-2023

High molecular weight – polycyclic aromatic hydrocarbons (HMW-PAH) are often found where air, water, and soil are subject to higher levels of industrial pollutants. These molecules are environmentally concerning due to their carcinogenic, mutagenic, and tumorigenic propensities. Furthermore, the isomers in this family are challenging to separate due to similar retention parameters, spectroscopic fingerprints, and mass spectral patterns. The primary purpose of this dissertation is to expand on the methodology for separation and analysis of the molecular mass 302 Da six-ring isomers using High Performance Liquid Chromatography. Retention behaviors of 21 commercially available isomers in synthetic mixture were collected via …

The Dynamical Measurement And Modeling Of Metacognition And Engagement Using Self-Report And Multimodal Data With Advanced Learning Technologies, Megan Wiedbusch

Electronic Theses and Dissertations, 2020-2023

Interdisciplinary research has demonstrated that learning and problem solving with advanced learning technologies (ALTs) such as intelligent tutoring systems, simulations, hypermedia, serious games, and virtual reality can promote and foster the development of 21st century skills (e.g., collaboration, problem solving, self-regulated learning) by measuring and using the interactions between cognitive, affective, metacognitive, motivational, and social (CAMMS) processes. Interdisciplinary researchers focused on self-regulated learning (SRL) have developed several theoretical models which model students' CAMMS processes and their learning behaviors. However, when empirically testing these models, researchers face complicated methodological decisions around modeling, measuring, processing, and analyzing student data. Many of these …

Algorithms And Variations On The Positional Burrows-Wheeler Transform And Their Applications, Ahsan Sanaullah

Electronic Theses and Dissertations, 2020-2023

In this dissertation, we develop algorithms and variations on the Positional Burrows-Wheeler Transform (PBWT). The PBWT is a data structure that stores M binary strings of length N while allowing efficient search. We develop the dynamic-PBWT (d-PBWT). The d-PBWT is a variation of the PBWT that allows its relevant algorithms to run with unchanged time complexity, but also allows efficient insertion and deletion of haplotypes. We provide insertion and deletion algorithms on the PBWT with average case O(N) time complexity. We also improve upon the query algorithms for the PBWT. Durbin described a set maximal match query algorithm on the …

Spatial Ensemble Distillation Learning Based Real-Time Crash Prediction And Management Framework, Md Rakibul Islam

Graduate Thesis and Dissertation 2023-2024

Real-time crash prediction is a complex task, since there is no existing framework to predict crash likelihood, types, and severity together along with a real-time traffic management strategy. Developing such a framework presents various challenges, including not independent and identically distributed data, imbalanced data, large model size, high computational cost, missing data, sensitivity vs. false alarm rate (FAR) trade-offs, estimation of traffic restoration time after crash occurrence, and real-world deployment strategy. A novel spatial ensemble distillation learning modeling technique is proposed to address these challenges. First, large-scale real-time data were used to develop a crash likelihood prediction model. Second, the …

Acausal Modeling Of Wind Turbines With Validation And Control Studies, Kazi Ishtiak Mohsin

Graduate Thesis and Dissertation 2023-2024

This thesis involves the modeling, validation, and control studies of a Control-Oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), that is currently under development. CRAFTS uses Modelica®, an object-oriented, declarative, multi-domain modeling language for physical system modeling in the Dymola environment. The CRAFTS simulator facilitates rapid dynamic simulation of wind turbines with various model variants and enables control co-design.

A major emphasis of this thesis is in the validation of the CRAFTS simulator for a 15-MW land-based wind turbine through several test cases. These test cases were collaboratively developed in conjunction with other participating research entities. CRAFTS has undergone rigorous …

Reconstructing 3d Humans From Visual Data, Ce Zheng

Graduate Thesis and Dissertation 2023-2024

Understanding humans in visual content is fundamental for numerous computer vision applications. Extensive research has been conducted in the field of human pose estimation (HPE) to accurately locate joints and construct body representations from images and videos. Expanding on HPE, human mesh recovery (HMR) addresses the more complex task of estimating the 3D pose and shape of the entire human body. HPE and HMR have gained significant attention due to their applications in areas such as digital human avatar modeling, AI coaching, and virtual reality [135]. However, HPE and HMR come with notable challenges, including intricate body articulation, occlusion, depth …

Safety Considerations For Setting Variable Speed Limits On Freeways, Md Tarek Hasan

Graduate Thesis and Dissertation 2023-2024

This thesis focuses on evaluating the appropriate speed at which vehicles should travel under different traffic conditions on freeways and its impact on crash frequency. The common belief is that the lower speed results in fewer crashes as reduced speed provides drivers with more time to react effectively and avoid collisions. However, this perspective overlooks the interplay among traffic speed, average spacing between consecutive vehicles, and the distance available for stopping a vehicle. Hence, we propose a safety parameter termed ‘Safety Correlate' (SCORE), which is defined as the proportion of average spacing relative to the stopping distance. To determine the …

Understanding Workforce Agility At Nasa Kennedy Space Center, Ledlyne H. Vazquez

Graduate Thesis and Dissertation 2023-2024

This study aims to define workforce agility via a literature review and a conducted research survey of the Kennedy Space Center (KSC) Engineering workforce. The survey results will help us determine the workforce agility of the KSC engineering team and understand what has allowed them to transition from the Space Shuttle Program to the new Exploration Ground System (EGS) program. Structural Equation Modeling was used to develop a model of relationships to test the hypotheses. The results show that organizational practices and psychological empowerment significantly support workforce agility. The implications of this study for understanding the characteristics of workforce agility …

Social Media-Based Crisis Communication: Analysis Of Twitter Data From Local Agencies During Hurricane Irma, Naiyara Noor

Electronic Theses and Dissertations, 2020-2023

As social media platforms have become vital means of communications, it has become imperative for emergency managers and policy makers to understand how people are interacting with different agencies on these platforms for enhancing community response coordination during disasters. Although many public agencies have already adopted social media platforms for crisis communication purposes, empirical evidence on whether and how these agencies are effectively engaged on these platforms is lacking. This research aims to examine crisis communication activities of a variety of agencies on Twitter in response to Hurricane Irma in 2017. In this study, we analyzed 13,353 hurricane-related tweets posted …

Improving Deep Neural Network Training With Knowledge Distillation, Dongdong Wang

Electronic Theses and Dissertations, 2020-2023

Knowledge distillation, as a popular compression technique, has been widely used to reduce deep neural network (DNN) size for a variety of applications. However, in recent years, some research had found its potential for improving deep neural network performance. This dissertation focuses on further exploring its power to facilitate accurate and reliable DNN training. First, I explored data-efficient method for blackbox knowledge distillation where the specifics of the DNN for distillation is inaccessible. I integrated active learning and mixup to obtain significant distillation performance gain with limited data. This work reveals the competence of knowledge distillation to facilitate large foundation …

Methodologies For Evaluating Interaction Cues For Virtual Reality, Xinyu Hu

Electronic Theses and Dissertations, 2020-2023

Virtual reality (VR) games and educational systems commonly employ interaction cues to provide information on how to take appropriate actions at particular moments. Interaction cues can be employed for different purposes, such as informing the user to look, go, pick, and operate. Additionally, different types of interaction cues can directly affect usability and user experiences. In our early research, we conducted two ecologically valid empirical studies with a preexisting VR training application and evaluated the effects of delayed interaction cues, in addition to comparing the purposes of interaction cues for learning and retention. Our results indicated that immediate interaction cues …

Towards Optimization And Robustification Of Data-Driven Models, Ehsan Kazemi Foroushani

Electronic Theses and Dissertations, 2020-2023

In the past two decades, data-driven models have experienced a renaissance, with notable success achieved through the use of models such as deep neural networks (DNNs) in various applications. However, complete reliance on intelligent machine learning systems is still a distant dream. Nevertheless, the initial success of data-driven approaches presents a promising path for building trustworthy data-oriented models. This thesis aims to take a few steps toward improving the performance of existing data-driven frameworks in both the training and testing phases. Specifically, we focus on several key questions: 1) How to efficiently design optimization methods for learning algorithms that can …

From Human Behavior To Machine Behavior, Zerong Xi

Electronic Theses and Dissertations, 2020-2023

A core pursuit of artificial intelligence is the comprehension of human behavior. Imbuing intelligent agents with a good human behavior model can help them understand how to behave intelligently and interactively in complex situations. Due to the increase in data availability and computational resources, the development of machine learning algorithms for duplicating human cognitive abilities has made rapid progress. To solve difficult scenarios, learning-based methods must search for solutions in a predefined but large space. Along with implementing a smart exploration strategy, the right representation for a task can help narrow the search process during learning. This dissertation tackles three …

Characterizing Air Plasma Sprayed Aluminum Oxide Coatings For The Protection Of Structures In Lunar Environments, Perla Latorre Suarez

Electronic Theses and Dissertations, 2020-2023

Wear-resistant ceramic and ceramic composite coatings are significant to provide durability and support long-duration missions to the moon's surface for rovers, landers, robotic systems, habitats, and many other components. On the Lunar surface, structural components are continuously exposed to lunar dust projectiles that can cause protective coating delamination around the affected area, of protective coatings and this may not be physically visible. Ceramic coatings, composed of alumina, present excellent resistance to different types of wear due to their high strength and hardness as well as the ability to protect structural components from regolith impacts, wear, and abrasive damage. Air Plasma …

Effect Of Autoclave Process Parameters On Mechanical Behaviors Of Carbon Fiber Reinforced Polymer Composites Fabricated Via Additive Manufacturing, Quang Hao Nguyen

Honors Undergraduate Theses

Additively manufactured carbon fiber reinforced polymers (CFRP) are vastly studied for their remarkable mechanical properties compared to most other 3D printed materials. Different methods were employed to further increase mechanical performance of CFRP 3D printed parts. The objective of the study is to investigate the effect of autoclave postprocessing on the interlaminar shear behavior between 3D printed CFRP layers. 3D printed CFRP samples were processed with nine combinations of temperature and vacuum in an autoclave. Short beam shear (SBS) tests were performed to characterize the interlaminar shear strength (ILSS) of the samples after autoclave processing. Digital image correlation (DIC) was …

Comparing Phosphorus Removal Efficiencies And Mechanisms Via Two Cost-Effective Specialty Adsorbents In A Cascade Upflow Filtration System, Sydney Kilgus-Vesely

Honors Undergraduate Theses

Finding solutions to treat water that contains phosphorus is an important effort due to the harmful impacts it presents to both human health and the environment. Phosphorus is considered a limiting factor in water oftentimes and therefore controls the growth of algal bloom in a water body. The increase of algal populations due to wastewater effluent, stormwater runoff, and agricultural discharge in Florida waters has a direct link to the event of harmful algal blooms such as red tide in coastal regions, eutrophication of waterbodies, and fish kills. Finding low cost, energy efficient, and low maintenance green sorption media (GSM) …

A Framework For The Automatic Identification Of Optimized Yield Surface Parameters, Kevin Hanekom

Honors Undergraduate Theses

Advanced engineering materials are designed to display tensile-compressive asymmetry (TCA) and anisotropy to provide unique attributes to critical components necessary in the hot section of turbines. The never-ending chase for higher efficiencies, and with them, higher temperature gradients, intrinsically leads to more and more of these complex materials, like single crystal turbine blades, embedded within the turbine environment. Mathematical models, known as yield criteria, allow engineers to visualize the mechanical behavior of these materials in various orientations under complex loading. Yield criteria are dependent on three key items in determination of their governing parameters: material test data, mathematical constraints, and …

A Framework Of Critical Success Factors For Implementation Of Industry 4.0 In Aerospace And Defense Industries, Lina Khan

Electronic Theses and Dissertations, 2020-2023

The fourth industrial revolution, or Industry 4.0, is essential to the success of Aerospace and Defense (A&D) organizations as it showcases the ability to adapt, innovate, and remain competitive. Industry 4.0 technologies such as cyber-physical systems (CPS), big data, cognitive computing, smart factories, connected manufacturing, and the Internet of Things (IoT) focus on revolutionizing manufacturing through embedding digital and physical systems, with the goal to maximize the desired output(s) while using minimal resources. Although there are numerous advantages, there are challenges associated with implementation of these complex systems. This doctoral research investigates the critical factors needed for successful implementation of …

Globally Distributed Teams: The Between-Team Barriers That Impede The Successful Delivery Of Agile Software Development, Ben Park

Electronic Theses and Dissertations, 2020-2023

Software development projects fail far too often, costing companies billions in revenue, loss of the intended purpose and damage to both customers and suppliers in the process (A. Shenhar & V. Holzmann, 2017a). Understanding the challenge of ever-failing globally distributed software development projects is the goal and research conducted in this dissertation. The vision guiding the direction of this research is "What are the betweenteam barriers that impede the successful delivery of Agile software development in Globally Distributed Teams?" Through the literature review, a model was created and refined. A Mixed-Method Sequentially Replicated Case Study Research was performed to determine …

Variational Autoencoder And Sensor Fusion For Robust Myoelectric Controls, Keith A. Currier

Honors Undergraduate Theses

Myoelectric control schemes aim to utilize the surface electromyography (EMG) signals which are the electric potentials directly measured from skeletal muscles to control wearable robots such as exoskeletons and prostheses. The main challenge of myoelectric controls is to increase and preserve the signal quality by minimizing the effect of confounding factors such as muscle fatigue or electrode shift. Current research in myoelectric control schemes are developed to work in ideal laboratory conditions, but there is a persistent need to have these control schemes be more robust and work in real-world environments. Following the manifold hypothesis, complexity in the world can …

Modeling Individual Activity And Mobility Behavior And Assessing Ridesharing Impacts Using Emerging Data Sources, Jiechao Zhang

Electronic Theses and Dissertations, 2020-2023

Predicting individual mobility behavior is one of the major steps of transportation planning models. Accurate prediction of individual mobility behavior will be beneficial for transportation planning. Although previous studies have used different data sources to model individual mobility behaviors, they have several limitations such as the lack of complete mobility sequences and travel mode information, limiting our ability to accurately predict individual movements. In recent years, the emergence of GPS-based floating car data (FCD) and on-demand ride-hailing service platforms can provide innovative data sources to understand and model individual mobility behavior. Compared to the previously used data sources such as …

Musical Form Reconstruction In Printed And Handwritten Lead Sheets Via Optical Recognition Of Chord Symbols, Nashir A. Janmohamed

Honors Undergraduate Theses

Optical music recognition (OMR) is the field of study which seeks to use computer vision to extract musical information from images. Most OMR work focuses on music symbols (such as notes, time signatures, clefs, etc.); to date, only two prior works pay attention to chord symbols (shorthand notation commonly used in jazz and popular music lead sheets to describe the harmony of the music) in musical documents. Chord symbols lay the foundation for jazz improvisation - a sequence of chord symbols is repeated during the improvisatory section, and the soloist and accompaniment (primarily, though not exclusively) use the chord symbols …

A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva

Electronic Theses and Dissertations, 2020-2023

Shape memory alloy (SMA) heat engines possess an inherent property of sensing a change in temperature, performing work, and rejecting heat through the shape memory effect resulting from a temperature-induced phase transformation. This work presents a framework for the design and implementation of an SMA-based Stirling heat engine for maximum power or speed incorporating and combining mechanical, thermal, and material aspects. The motivation for this work comes from the growing need for reliable thermal management and energy recovery in both ground and space applications of interest to NASA and commercial space companies. In future lunar and Mars missions, an SMA …

Effect Of Particle Size On Mechanics Of Particle Reinforced Composites Using Photoluminescence Piezospectroscopy, Khanh Vo

Electronic Theses and Dissertations, 2020-2023

Nanoparticle reinforced composites are greatly desired by the aerospace community for a multitude of applications for their tailorable quasi-isotropic mechanical properties such as the high strength-to-weight ratio. With increasing demand of structural nanoparticulate composites, the optimization of their structural integrity and performance can be improved with a better understanding of the load transfer mechanics. Extensive nanoparticulate composites research has focused on the roles of particle shape, size, and volume fraction on the mechanical properties. Nanocomposites are often experimentally characterized through the determination of the bulk composite material properties. Load transfer research with a micro-mechanics perspective, distinguishing particle and matrix behavior, …

Machine Learning Applications In Advanced Additive Manufacturing: Process Modeling, Microstructure Analysis, And Defect Detection, Peter Warren

Electronic Theses and Dissertations, 2020-2023

Non-destructive evaluation (NDE) techniques are critical for assessing the integrity, health, and mechanical properties of materials manufactured from various methods. High fidelity NDE techniques are essential for quality control but often lead to massive data generation. Such a vast data load cannot be manually processed, this leads to a severe bottleneck for process engineers. Machine learning (ML) offers a solution to this problem by providing powerful and adaptable algorithms capable of learning patterns, identifying features, and finding hidden relationships in large sets of data. Various ML models are used in this work to improve predictions, improve measurements, detect anomalies, classify …