Digital Commons Network^™

Analyzing Qualitative Data Collection Methods In Systems Engineering, Rosemary Cortelli

Theses

The goal of this thesis is to expand the research on human decision-making in engineering systems by exploring qualitative data collection methods utilized in systems engineering. Analyses are performed to identify differences in qualitative data collection method use across the life cycle and throughout technical processes. 495 sources were evaluated for qualitative data collection method use identified from systems engineering literature and analyzed using statistical analyses. Of these, 93 sources utilized data collection methods of documentary analysis, narratives, focus groups, observations, and interviews which traced across every life cycle phase and most technical processes. The findings show there are significant …

Spectropolarimetric Properties Of Vortex Retarders, Ella Elizabeth James

Theses

Vortex retarders are unique optical elements that create a uniform electric field phase retardance, but the traditional fast axis varies azimuthally over the area of the optic. This affects the radial and azimuthal polarization components of the incoming beam. The vortex retarders discussed here generate TEM10 and TEM20 Laguerre-Gaussian beams. While several varieties of these TEM10 and TEM20 vortex retarders exist, designed to function at specific wavelengths–and a few studies have reported their use at those wavelengths–almost no data exists detailing their polarimetric properties outside those wavelengths. Using a Mueller matrix spectropolarimeter with dual-rotating retarders, the polarization properties of four …

Development Of Tungsten Rhenium Hafnium Carbide Tooling For Friction Stir Welding Of Nickel Based Superalloys, Zachary H. Perrin

Theses

Development of advanced high strength and high temperature tool materials are required for solid-state friction stir welding (FSW) of nickel-based superalloys. FSW tooling must be able to survive at the temperatures experienced in the FSW weldment in conjunction with very high mechanical loading. Thus improving the durability of FSW tool materials is critical to producing acceptable welds and expanding FSW application areas. The refractory alloy Tungsten-Rhenium-Hafnium Carbide (W-25%Re-4%HfC) is able to operate at temperatures of over 1000 °C, while maintaining the ductility required for good. Building upon previous research that demonstrated the 4% Hafnium Carbide (HfC) additive’s ability to yield …

Generation Of True Random Numbers With A First Order Chaotic Circuit, Austin Davis

Theses

True randomness backed by first principles theory is surprisingly rare in physically implemented circuit for cybersecurity applications. This thesis provides an illustrative case of a chaotic one-dimensional map circuit with a design driven by a need for rudimentary theory concerned with the limits of its entropy production. Analysis, simulation, and hardware measurements are evaluated against statistical randomness tests issued by the National Institute of Standards and Technology. Interestingly, the results provided here highlight strong relationships between first principles theory of design and measured results when varying parameters. We observe matching characteristics between analytic, simulated and measured hardware results for NIST …

Enhancing Accessibility : A Pilot Study For Context-Aware Image-Caption To American Sign Language (Asl) Translation, Oluwafolahanmi Adedamola Aluko

Theses

Since the advent of Artificial Intelligence (AI), and the explosion of Generative AI, much work has been done around image captioning, providing wildly accurate captions from still images, and more recently videos [3]. Alt-Text has improved dramatically with efforts to enhance context and sentiment captured during automated captioning. This thesis attempts to expand on a section on Natural Language Processing (NLP) and its relevance to promoting accessibility and context-awareness in the premise of the American Sign Language (ASL) application. This thesis explores what it means to give full context about a caption or image to the end user, including sentiments, …

Establishing A Seven-Stage Iterative Framework And Card-Based Toolkit For The Facilitation And Sustainment Of Communities Of Practice, Michelle O'Keeffe

Theses

This thesis explores the establishment of a framework and card-based toolkit to support the facilitation and sustainment of Communities of Practice (COPs), with a particular focus on COPs in the education domain. COPs have been present in various sectors, such as healthcare, business, finance, and education, for over three decades. These communities bring together individuals who share common problems, concerns, or areas of expertise, aiming to improve their practices collectively. However, there is a lack of understanding regarding the best approaches to facilitating, developing, and sustaining COPs over time. To address this gap, four empirical studies were conducted. These studies …

Economical And Environmental Evaluation Of Non-Residential Demand Response In The European Transition To Zero-Carbon Energy, Markus Fleshutz

Theses

To meet climate objectives, major energy consumers with local multi-energy systems (L- MESs) must transition to renewable energy sources soon. The variability of renewable energies requires increased operational flexibility for integration. In this context, demand response (DR), a strategy in which electricity consumers adjust their load profiles in response to incentives, has become crucial, offering cost-effective flexibility. It supports L-MESs in integrating renewable energy, reducing decarbonization costs, and enhancing resilience. However, quantifying the economic DR potentials for L-MESs under carbon emission constraints is complex, especially when considering investment options in distributed energy resources. This complexity hinders the rapid adoption of …

An Ontology Based System For Cancer Diseases Knowledge Mining, Shinead Casey

Theses

National cancer registries play an important role in understanding the patterns and trends of cancer diseases, prevention methods, and treatment management. However, issues arising from data silos and an inability to link heterogeneous data sources have led to problems within the healthcare industry. This became apparent in Ireland in 2018 when Dr Scally’s scoping inquiry into the CervicalCheck controversy highlighted patient safety issues relating to disjointed data and an inability to link datasets.

Worldwide, semantic technologies are being utilised for their ability to link diverse data and enhance analytical capabilities. Therefore, this thesis will examine the use of a knowledge …

Consumer Acceptance And Sensory Evaluation Of 3d Printed Dairy Snacks, Laura Davis

Theses

3D printing technology has been established since the early 1980s by the inventor Charles Hull, with its initial applications in the moulding of plastic veneers for furniture. More recently, 3D printing has been gaining popularity as a food technology due to its potential benefits, such as personalised nutrition and reduced environmental impact. This study explored the consumer acceptability of 3D printed dairy snacks across participants in the UK and Ireland, through an online survey and sensory trials. The online survey was designed and distributed across 402 UK participants and 400 Irish participants. The sensory trial was conducted with a group …

Improving The Most Gg Model To Predict Environmental Impact And Improve On Farm Grass Growth Prediction, Laeticia Bonnard

Theses

The increasing need for highly productive and eco-friendly agriculture is driving demand for decision-support tools to assist agricultural operators in managing systems more precisely and sustainably. Although grasslands provide a cost-effective option for ruminant production and can offer many environmental benefits (biodiversity, carbon storage etc.), grasslands management is challenging due to the inherent climate and soil sensitivities and their potential negative impact on water quality. In Ireland, the Moorepark Saint Gilles Grass Growth (MoSt GG) model was developed for the dual purposes of research-based simulations and on-farm grass growth prediction for farmers. The objective of this thesis was to improve …

Cybernetic Hustle A Hard-Boiled Science Fiction Short Story, Eric Morris

Theses

In a world where body enhancement technology, or "cybernetics," should allow for exponential human progress, the gap between social classes is as wide as ever. A team of cybernetic bootleggers seek to even this playing field by providing low-cost implants to the working poor. Their operation becomes threatened when other underworld groups begin to raise police suspicions, but in this world, the cops may be more corrupt than the criminals. It is up to the team to expose the threat to their business, stay under the radar of the law, and risk their own futures in order to preserve their …

Design And Kinematic Testing Of A Resin Artificial Monarch Butterfly Wing, Thomas Payne Clark

Theses

Due to its ability to travel long distances efficiently, as evidenced by its yearly migration, the monarch butterfly is a strong candidate upon which to base a micro-aerial vehicle. Of primary importance in this venture is designing artificial wings with similar kinematics to a monarch wing. A first attempt produced a wing that differed significantly from a monarch wing in terms of deformation while flapping and empirical force coefficient trends. Using a new resin-based 3D printer, a new wing has been designed and developed to improve upon the issue with the original artificial wing. Both wings are tested using a …

Evaluating The Effects Of L-Pbf Printing Parameters On The Microstructure And Mechanical Properties Of Grcop-42, Elaina Walker

Theses

GRCop-42 is a dispersion strengthened copper alloy of interest due to its high thermal conductivity. Since it is fabricated as a powder, it is adaptable to powder based, metal additive manufacturing (AM) processing. The chromium-niobium additives phase separate from the copper matrix and form strengthening dispersoids during the gas atomization process used to produce the powder. This study looks at the effect of the powder based, laser powder bed fusion (L-PBF) AM processing parameters on the resulting microstructure and mechanical properties. Builds were obtained from five different vendors, deposited using their best practice, for metallurgical and mechanical property evaluation. By …

A Novel Method For Time-Based Synchronization Of Acquired Force And Motion Data, Darnisha Detraniece Crane

Theses

Enhancing the performance of flapping wing micro air vehicles hinges upon a thorough comprehension of the intricate interplay between wing kinematics and resulting forces. This understanding necessitates a method of synchronization capable of establishing a precise correlation of wing motion and force generation. The objective of this project is to develop a time-based synchronization method using existing hardware in the ATOM lab. Algorithms were developed to control the Vicon motion-tracking system and the ATI force sensor to achieve the synchronization of acquired data. Experimental testing was conducted to validate the algorithms and system architecture. Results from testing revealed a time …

Deep Learning Approach For Robust Structural Health Monitoring Using Guided Lamb Wave Responses, Sameer Gopali

Theses

Guided Lamb waves offer a promising solution for the early detection of internal damages in structures due to their high sensitivity to small damages. However, noise can adversely impact the development of data-driven models for damage detection, leading to inaccurate monitoring systems. This thesis explores deep learning techniques to robustly predict the location and severity of damage in cantilevered beams using noisy guided wave responses. Initially, Multi-Layer Perceptron (MLP) is trained with frequency domain features to achieve robust performance against noisy data. Further performance improvement is achieved using end-to-end learning models, which include autoencoder and one-dimensional Convolutional Neural Network (CNN). …

Functionalizing Silicon Oxide Like Surfaces With Fatty Acids, Maman Sani Maman Brah Maman

Theses

The goal of this project was to make flat hydrophilic, silicon oxide-like surfaces hydrophobic. Using fatty acids in a wet chemistry approach. Glass, mica, and silicon wafer surfaces were cleaned with standard methods from the literature. The substrates were functionalized with oleic acid and stearic acid in ethyl alcohol. The solution concentration was held constant at 100 times a theoretical minimum concentration. The substrates were immersed at various functionalization times and various solution temperatures. Contact angle goniometer was used to measure the contact angle for water on the functionalized surfaces. The results confirmed that glass and oxidized silicon wafer surfaces …

The Design And Testing Of A One Megaampere Pulsed Power System, Logan Towers

Theses

This thesis details the design, construction, and testing of a 1 megaampere (MA) class pulsed power system (PPS) named Sparky. Sparky's creation stemmed from the desire to explore subscale fusion experiments, where a strong correlation between fusion yield and peak current has been observed. The system offers reconfigurability through diverse load attachments enabling it to deliver currents ranging from 105 to 106 amps and cater to various experimental needs. Sparky is a 60 kJ capacitor bank consisting of six 13.5 µF capacitors rated at a maximum charging voltage of 35 kV. Most of our tests, which consisted of discharging Sparky …

Quasi-Static And Dynamic Tension Testing Of As-Built And Heat-Treated Additively Manufactured 316l Stainless Steel, Terrell Elias Marler

Theses

Additive manufacturing (AM) has several advantages over conventional subtractive manufacturing techniques, including the ability to create parts of highly complex geometries in one process thus reducing time and cost for each part. However, AM parts show different mechanical behavior compared to wrought parts due to the differences in the manufacturing processes. In particular, lack-of-fusion defects, voids, and keyhole defects can act as crack initiation sites leading to the possibility of more brittle behavior. This may be exacerbated by high rate loads, which tends to induce more brittle behavior, higher flow stress, and higher yield stress in materials. Therefore, it is …

Spectral Deconvolution Using Machine Learning For Determining Material Compositions In Mixed Samples, Prakash Chaudhary

Theses

Hyperspectral unmixing is essential in determining material compositions in mixed samples with a larger number of endmembers, but achieving precise decom- position remains challenging due to the limited work done, the presence of spectral variability, and endmember complexities. This study proposes many machine learning methods and techniques to identify the material composition in mixed samples (composites). Other methods to solve this problem mainly focus on a very small number of endmembers; our approach works with many end members, improving the model’s robustness. The proposed methods effectively tackle spectral variability, high dimensionality, and the presence of similar endmembers by integrating a …

The Design, Implementation, And Evaluation Of A Hybrid Sensemaking Tool Combining Traditional Physical Devices With Augmented Reality, Kaden Gryphon

Theses

This thesis is about our work integrating traditional devices, for example, mobile and stationary displays, into an augmented reality (AR) tool for analyzing data during sensemaking tasks. We create a framework for breaking down analysis tasks into three steps. Using our framework we design and implement the AR bulletin board (ARBB).We conduct a user study to evaluate ARBB, using the results and user feedback to create design implications. Our study supports that having a physical device helps users complete interactions faster, and users are more likely to use the tools during sensemaking to create more complex organizations.

Clearscan : A Machine Learning System For Customized, Site-Specific Radar Image Filters, Erick Jones

Theses

In the field of radar meteorology, a perpetual problem is removal of so-called anomalous propagation (AP), i.e. non-precipitation echoes, from the produced images. Much work has been done in this area already, including conventional heuristic algorithms as well as machine-learning systems such as neural networks. Often the focus is on certain familiar radar architectures such as WSR-88D, also known as NEXRAD. However, a large number of radars exist which are not identical to NEXRAD; and there are also environmental differences such as RF interference which can affect the success rate of existing AP removal strategies. The focus of this paper …

Data Remanence Vulnerabilities In Embedded Sram At Low Temperature, Farzana Hoque

Theses

Static Random Access Memory (SRAM) memory is prevalent as cache memory in computing platforms and embedded systems. SRAM frequently stores essential information such as cryptographic keys, passwords, and other confidential data. Consequently, a data remanence-based attack on SRAM can result in significant damage. When power is removed, SRAM gradually loses data rather than immediately, especially at lower temperatures. This phenomenon, known as data remanence, poses a significant security risk, as it can be exploited through cold boot attacks targeting encryption keys and other sensitive data. Understanding temperature-induced vulnerabilities in embedded SRAM is crucial for enhancing the security and reliability of …

The Effects Of Reducing Carbon Content In The Processing Of Superalloy Inconel 718, Glenn "Joey" Scott

Theses

The properties of Inconel 718 (IN718) are dependent on the elemental composition and microstructure. Applications using IN718 include rocket and jet engine parts. These parts are often complex and difficult to machine, making IN718 ideal for additive manufacturing processes such as laser-powder bed fusion (L-PBF). The various phases that form in IN718 rely on the niobium (Nb) content including the carbides. The precipitates also include Nb in the strengthening phases of gamma prime and gamma double prime. Overaging of gamma double prime transforms the metastable phase into the stable delta phase, which also controls grain size. This study evaluates the …

Aerodynamic Losses Of Additively Manufactured Blades In Transonic Conditions With Different Surface Treatments, Chase Allen Herrin

Theses

Additive manufacturing (AM) allows the production of high strength and high temperature alloys to increase the operational temperature of turbines and other engine components. AM inherently has high surface texturing, inclusive of waviness due to the layering effect in the laser powder bed fusion (L-PBF) process, and roughness due to surface defects such as partially sintered powder, deep notches, and micro-cracks. This thesis investigates how different surface treatments affect the surface static pressure variations and wake aerodynamic loss characteristics for each blade. A supersonic transonic blow down wind tunnel with a linear cascade test section is used to acquire this …

Characterization And Analytical Prediction Of The Effective Elastic Modulus In Additively Manufactured Body-Centered Cubic Lattice Structures, Peyton Hall

Theses

Advancements in metal additive manufacturing have enabled the production of metal lattice structures. The customizability of the lattice topology offers the potential to yield lightweight materials with highly tailored thermal and mechanical properties. By building on well-established models of other cellular solids such as metal foams, the intricate structural behavior of these lattices is simplified to effective values for key mechanical properties which are given as a function of the relative density of the lattice as well as certain material and lattice parameters. It is intended that these effective values will be used to represent the lattice at a macroscopic …

Constructing Other Worlds: An Intertextual Analysis Of Cow Eye Press, Adrian Jones Pearson And The Works Of A.J. Perry, James A. Galliher

Theses

Cow Eye Press, A.J. Perry, and the pseudonymous Adrian Jones Pearson have largely been ignored by academics. Between 2001 and 2021, Perry composed a collection of texts which this study calls the Cow Eye Project. The project received brief attention when critics and journalists began comparing Pearson to Thomas Pynchon. However, the online spectacle overshadowed engagement with the texts themselves. This thesis exists to document the project and foreground Perry’s works on their own merits to examine their value and position within contemporary American literature. Previous scholars have treated the texts individually. This thesis argues that the central texts of …

Development Of A High Speed Differential Temperature Sensor For In Situ Estimations Of Cn2 In The Planetary Boundary Layer, Michael C. Yurovchak

Theses

The propagation of electromagnetic energy through the Earth’s atmosphere is significantly modulated by spatial variability of the refractive index structure function (Cn2). In situ estimates of vertical profiles of Cn2 in the boundary layer are critical for evaluating model predictions and ground-based remote sensing retrievals of Cn2. This thesis describes the development of a sensor system that produces high frequency measurements of differential temperature between two points in space separated by a distance of 0.3m using two 5 𝜇𝑚 diameter platinum resistance temperature sensors with 10-4K resolution. The platinum wire sensors are connected to two legs of a Wheatstone Bridge …

Grating Lobe Suppression Techniques In Sparse Linear And Planar Phased Array Antennas With Reconfigurable Phasor Elements, William M. Current

Theses

With the continual increase in the need for wireless communications, there comes a desire to decrease fabrication costs. One of the primary drivers for the cost of an antenna array is the actual number of antennas used. This number, however, can only be decreased so far for a fixed aperture area without causing undesired secondary main beams, grating lobes, to appear in the radiation pattern. This work aims to analyze the results of two methods for reducing these grating lobes in sparse, scanning phased array antennas. Both of these methods are based upon dual-mode antenna elements, as opposed to single-mode …

Characterization Of Thin-Walled W-24re Structures Fabricated Using Laser-Powder Bed Fusion, Madelyne Rushing

Theses

W-24Re is a refractory alloy used in high temperature applications due to its high melting point, recrystallization temperature, and tensile strength. Due to the high melting point, fabrication is more commonly achieved through powder metallurgy processing, which relies on diffusion. As the material is available as a powder, it is a good candidate for laser-powder bed fusion (L-PBF) processing. This study focuses on characterization of L-PBF of W-24Re thin-walled structures to determine the feasibility and primary failure mechanisms under tension compared to that of bulk W-24Re. A laser parameter set was developed, and samples were provided by Quadrus Corporation for …

A Comparative Study Of Methods For Modeling Python Source Code Semantic Similarity, Binita Gyawali

Theses

In this thesis, we did comparative study of various methods for generating Python source code embeddings and evaluated their effectiveness using semantic labels. We used both word embedding models, such as Word2Vec and GloVe, and document embedding models to capture the semantic meaning of Python source code. In terms of word embedding evaluation, Word2Vec, combined with cosine distance, achieved the highest nearest neighbor precision of 0.5790. For evaluation of Python source code (or document) embeddings, our analysis across two datasets showed that Doc2Vec, paired with cosine distance, outperformed other methods in semantic code similarity detection, achieving an AUROC between 0.80 …