Digital Commons Network^™

Quantitative Modeling Of Text-Based Intelligence Source Uncertainty, Adam D. Nesmith

Theses and Dissertations

An all-source intelligence analyst’s primary job is delivering timely, well-sourced assessments on relevant targets based on uncertain and incomplete information. Each assessment includes a likelihood that the assessment is true, and a confidence level based on the uncertainty of the sources used. Quantitative all-source intelligence analysis is not widely implemented despite the acknowledged limitations of qualitative intelligence assessments and the existence of proposed quantitative methods. This is due to the challenge of quantitatively representing uncertainty in text-based intelligence reporting (i.e., HUMINT, OSINT, SIGINT), which limits the effectiveness and usability of previously suggested methods. This research creates a novel framework for …

Failure Distributions For Parallel Dependent Identical Weibull Components, Gina S. Sigler

Theses and Dissertations

For a parallel system, when one component fails, the failure distribution of the remaining components will have an increased failure rate. This dissertation takes a novel approach to finding the associated failure distribution of the full system using ordinal statistic distributions for correlated Weibull components, allowing for unknown correlations between the dependent components. A Taylor series approximation is presented for the two component; system failure time distributions are also derived for two failures in a two component system, two failures in an n component system, three failures in a three component system, and k failures in an n component system. …

Emitter Selection Optimization For Passive Synthetic Aperture Radar, Mu Kim

Theses and Dissertations

Widely distributed modern communication networks provide excellent opportunities to share the spectrum for passive radar systems, of which emitter selection is a major consideration factor. This research introduces emitter selection problem space, which consists of three SAR processing domains, namely, Data Collection, Image and Mission Performance Domains. Quantitative links between these domains are critical to formulate an optimal emitter selection problem in the Data Collection Domain and/or Image Domain, which satisfies given mission requirements in Mission Performance Domain. This research examines the properties of the SAR processing domains to develop performance metrics in the Data Collection and Image Domains, whose …

Portfolio Optimization Using Value Focused Thinking, Tyler Martin

Theses and Dissertations

This thesis explores the application of Value Focused Thinking (VFT) and multi-objective portfolio optimization to create a well-aligned portfolio for an organization faced with over 50 alternatives and limited funding. A novel technique is proposed to develop an optimized portfolio based on VFT scores, utilizing heuristic approaches like evolutionary algorithms. The research outcomes include an optimized portfolio, the total value evaluation of alternatives, and a sensitivity analysis. The new approach outperforms the organization’s previous method, resulting in a portfolio that better addresses the organization’s core values and objectives, scoring 21.21% higher.

Design And Analysis Of Asymmetric “String-Of-Pearls” Common Repeating-Ground-Track Satellite Constellations For Missions Requiring Regional Coverage, Nathaniel Choo

Theses and Dissertations

Satellite constellation design must balance many factors that emerge from multiple sources, including environmental hazards and competing mission objectives. The dynamic nature of space systems makes the problem of ‘optimal’ satellite constellation design even more challenging. Restricting satellite constellation designs to predefined geometric frameworks can alleviate many challenges associated with the design problem; however, it raises an important question: which geometric framework performs best for each mission set? This research leverages simulations, metaheuristics, and mathematical programming techniques to address this question for missions focusing on Earth-observation of one or more regions.

First, this research captures the current state of satellite …

Non-Degenerate Two-Photon Absorption And Excited State Line Shapes In Alkali Vapors, Timothy M. True

Theses and Dissertations

The rubidium 5S-5D two-photon transitions were probed between 758-798 nm, where a six order of magnitude change in the cross section was observed and the polarization dependence was seen explicitly. Collisional rates are measured in cesium on the 6P-9S and 5D-10F transitions, with broadening rates as large as 710 MHz/Torr and shifting rates as large as 273 MHz/Torr. We observe Stark broadening on the cesium 5D-10F line shape, with Lorentzian width increasing from 200 MHz to 40 GHz. The influence of electron impact is discussed under these conditions and with 0-20 Torr of helium. Cascade amplified spontaneous emission is seen …

Fast And Accurate 3d Object Reconstruction For Cargo Load Planning, Adam R. Nasi

Theses and Dissertations

Cargo load planning involves efficiently packing objects into aircraft subject to constraints such as space and weight distribution. Currently, this is performed manually by loadmasters. The United States Air Force is investigating ways to automate this process in order to improve airlift operational readiness while saving money. The first step in such a process would be generating 3D reconstructions of cargo objects to be used by a load planning algorithm. To that end, this thesis presents a novel method for fast, scaled, and accurate 3D reconstruction of cargo objects. This method can scan a 2.5m×3m×2m object in less than 10 …

Temporal And Spatial Variability Of Specific Energy Consumption For Atmospheric Water Generators, Anthony T. Brenes

Theses and Dissertations

Atmospheric Water Generators (AWG) produce potable water from the moisture in the air, providing a potentially viable water source in austere locations or emergency response scenarios. In this study, the operating constraints of three existing commercially available AWG devices are investigated, compared to historical weather data from across the continental United States. Utilizing linear regression modeling and weather station data for the years of 1985-2019, the monthly and spatial trends of energy demand to produce water from these devices are evaluated. Energy and water production efficiencies for the devices are highly dependent on environmental conditions with relative humidity and temperature …

Developing And Assessing A Generalized Serious Game That Supports Customized Joint All-Domain Operations Related Learning Objectives, Jonathan D. Moore

Theses and Dissertations

As the threat of near-peer adversaries has increased, the DoD has increased its emphasis on Joint All-Domain Operations (JADO). This emphasis on JADO highlights the need for hands-on training that can engage military members at all levels. The serious game Battlespace Next (BSN) was designed to teach high-level JADO concepts by modeling real-world military assets in the context of a strategic card game. To keep pace with the evolving landscape of warfare as well as fit the needs of a variety of Department of Defense (DoD) communities, this research introduces the Battlespace Next Education Framework (BSNEF). The BSNEF allows JADO …

A Method For Monte Carlo Neutral Particle Radiation Transport In A Variable Density Atmosphere, Aidan B. Edens

Theses and Dissertations

This study focuses on accurately simulating the transport of radiation in the atmosphere to better understand the effects of nuclear weapons. The variable nature of the atmosphere poses a challenge in accurately simulating the prompt radiation following a nuclear explosion. To address this challenge, the Mass Integral Scaling technique is integrated with the Monte Carlo method to perform calculations in a variable density atmosphere. In addition to previous free-field estimates, this work also enables the simulation of transport calculations with other media, such as clouds. Results of neutron and photon fluence have been verified against the standard version of MCNP …

Exploring Variations In Fast Curing Plastic Scintillator Formulations: Optimizing Tpo And Evaluating The Effects Of High-Z Loading And Novel Waveshifters, Andrew K. Nesbitt

Theses and Dissertations

Organic plastic scintillators are widely used due to their relative low cost, physical robustness, and fast timing properties, but typically provide lower light yields and photon sensitivity compared to other alternatives. Photocuring novel plastics offers a viable method for producing fast curing plastic scintillators. The current formulations include an acrylic polymer base and utilize diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as the photo-initiator for polymerization; however at higher concentrations of TPO may adversely affect scintillator light output. The present research refined the optimal TPO concentrations that fully cure these acrylic-base scintillators and maximize light production to 0.4-0.5% by weight. Additionally, this …

Automated Additive Layering Of Vat Polymerized Plastic Organic Scintillators, Chandler J. Moore

Theses and Dissertations

The current technology for fast neutron detection imaging is limited in achieving the required high spatial resolution, strong neutron discrimination, and practical time of manufacturing. Traditional fabrication methods require days of thermal polymerization and hundreds of man-hours to produce average resolution pixelated scintillator arrays. The present work helps to eliminate this limitation by developing an additive manufacturing technique to construct such detectors for use in in dual particle imaging applications. In this work, fast-, light-curing resins are used in a prototype automated assembly machine, capable of layering of individual light-cured resin layers and optical segmentation with a self-bonded specular reflector, …

Student Performance In Traditional In-Person Vs. Online Sections Of An Introductory Graduate Mathematics Course, Lauran E. Kittle

Theses and Dissertations

The growth of technology impacts nearly every aspect of everyday life, to include education and learning. The availability of distance learning (online) classes has increased drastically in the last few decades, expanding access to education for millions of people. However, it is imperative to consider exactly how the growth of technology impacts education – whether it is a positive, negative, or neutral impact. Previous research comparing distance learning and in-residence (traditional) classes have widely mixed, disparate conclusions. This type of research, two-stage analysis, and modeling has yet to be conducted on a graduate school level. For this reason, a detailed …

Modeling Radiation Exposure On Flight Missions To Analyze Aircrew Risk, Camila V. Quintero Hilsaca

Theses and Dissertations

GCR and SPE comprise the majority of the ionizing radiation experienced in the upper atmosphere within flight-altitude environments. Although previous studies have analyzed radiation doses from single sources on civilian flight operations, there is a lack of research focused on dose received by military personnel during flight from both sources simultaneously. In-flight radiation environments are modeled through the MCNP6 for two separate aircraft, an Air Force A-10 and a Boeing 737. Particle fluence values for galactic cosmic rays and solar particle events for four separate flight paths are determined using the CARI-7A software and the SIRE2 toolkit, respectively. MCNP6 code …

Cellphone-Acoustics Based Suas Detection And Tracking, Ryan D. Clendening

Theses and Dissertations

Small Unmanned Aerial Systems (sUAS) are an easily accessible technology that has become an increasingly large threat to US critical systems. This threatening technology demands using fault-tolerant, low-cost, replaceable, and accurate sensing resources, which counter the ubiquitous nature of sUAS [1]. Therefore, the methods developed in this thesis detect and track sUAS using easily accessible sensing resources, such as cellphones. First, we develop an acoustics sensor network-based sUAS detection methodology. In the latter effort, a deep learning model is trained using the acoustics data from the data collection to predict sUAS range from a cellphone. Combined, these two efforts demonstrate …

Magnetic Anomaly Mapping For Navigation, Luke T. Bergeron

Theses and Dissertations

Magnetic navigation (MagNav) has the potential to provide a global form of navigation that uses magnetic measurements of the Earth’s anomaly magnetic field and compares those measurements to a magnetic anomaly map in order to determine the user’s position. Widespread use of MagNav will require a database of fully-sampled, low-altitude magnetic anomaly maps. Existing magnetic anomaly map databases usually come from under- or poorly-sampled surveys. In this work, we provide an easy to follow MagNav anomaly map generation framework and set of survey collection metrics/requirements in an effort to help facilitate and standardize the creation of such a database. We …

The Electromagnetic Bayonet: Development Of A Scientific Computing Method For Aperture Antenna Optimization, Michael P. Ingold

Theses and Dissertations

The quiet zone of a radar range is the region over which a transmitted EM field approximates a uniform plane wave to within some finite error tolerance. Any target to be measured must physically fit within this quiet zone to prevent excess measurement error. Compact radar ranges offer significant operational advantages for performing RCS measurements but their quiet zone sizes are constrained by space limitations. In this work, a scientific computing approach is used to investigate whether equivalent-current transmitters can be designed that generate larger quiet zones than a conventional version at short range. A time-domain near-field solver, JefimenkoModels, was …

Protection Of Linear Assets In Arctic Regions Using Basic Expeditionary Airfield Resources (Polaar Bear), Christopher P. Lintz

Theses and Dissertations

In the 2018 United States National Defense Strategy, the Department of Defense mandated that forces are to be more dynamic and decentralized. The Arctic region was a key topic that was addressed. This means that in the future, it is possible that personnel will need to operate in the Arctic, away from the standard built up infrastructure, to enhance the capabilities of the Air Force and enable the power projection required for mission execution. When establishing a new location, water systems are one of the first requirements for setting up a temporary base infrastructure. However, the Air Force’s current expeditionary …

Investigation Of Rhine Pointing As A Solution To The Aircraft Human Machine Interface Problem, Alexandra C. Dobranski, Samuel J. Medvec

Theses and Dissertations

The human machine interface in 5th generation aircraft has not evolved proportionally with advances in display size and data density. The traditional cursor slew method fails to rapidly relocate the cursor, especially on large displays. Previous studies at the Air Force Test Pilot School and Air Force Institute of Technology identified methods that have the potential to improve the human machine interface. This research expanded upon those studies by providing an assessment of head tracking technology as a secondary method of cursor manipulation. Specifically, this study examined the effects that visual feedback (visible and invisible head tracking cursors) and cursor …

The Kinetics Of Biocontaminant Inactivation: A Comparative Study With Bacillus Globigii And Bacillus Anthracis, Leigh M. Durden

Theses and Dissertations

Bacillus anthracis has been a biological threat for decades and after the 2001 terrorist attack via the U.S. Postal Service where five people died, there was heightened awareness and inquiry on the subject (Goel, 2015; Greenberg et al., 2010; Nicholson & Galeano, 2003; Spotts Whitney et al., 2003). The health risk to humans makes this biological agent, a Tier 1 agent and one of the most likely to be used in an attack (Anthrax as a Bioterrorism Weapon | CDC, n.d.; Driks, 2009; Rose & Rice, 2014). B. anthracis is one of most resistant and potent biological warfare agents as …

Sea Level Rise Impacts On Wastewater Treatment Plants And Their Social Vulnerability Differences, David S. P. Robinson

Theses and Dissertations

Many of the United States’ major cities that have a high population are located along the coast. The number of people residing in low elevation coastal areas, be-low 10 meters, is increasing. Coastal areas may be affected by various short- and long-term climate hazards, such as sea level rise (SLR). Climate change induced SLR will threaten residents and infrastructure in low-lying coastal areas. A household’s capacity to respond to hazards is highly dependent on its socio-demographic situation which determines its social vulnerability. Wastewater treatment facilities area particularly critical piece of infrastructure often located in low-lying areas due to gravity fed …

Decontamination Of Perfluoroalkyl Substances From Stainless Steel Piping Used In Aqueous Film Forming Foam Fire Suppression Systems, Ryan M. Register

Theses and Dissertations

This study examines the removal of perfluoroalkyl substances (PFAS) from legacy hangar fire suppression systems which utilized PFAS containing aqueous film forming foam (AFFF). Hundreds of these systems are currently in place throughout the Department of Defense, with planned phase-out occurring by 2024. The estimated cost of replacing these systems is $2.1 billion dollars. To mitigate this cost, a triple-rinse method of decontamination has been proposed. This thesis explores the release of PFAS from AFFF systems during a triple-rinse decontamination, and the continued removal of PFAS after a triple-rinse is complete while simultaneously analyzing methylene blue dye as a potential …

Garbage In ≠ Garbage Out: Exploring Gan Resilience To Image Training Set Degradations, Nicholas M. Crino

Theses and Dissertations

Generative Adversarial Networks (GANs) have received increasing attention in recent years due to their ability to capture complex, high-dimensional data distributions without the need for extensive labeling. Since their conception in 2014, a wide array of GAN variants have been proposed featuring alternative architectures, optimizers, and loss functions with the goal of improving performance and training stability. While this research has yielded GAN variants robust to training set shrinkage and corruption, our research focuses on quantifying the resilience of a GAN architecture to specific modes of image degradation. We conduct systematic experimentation to determine empirically the effects of 10 fundamental …

Lunar Search And Rescue: The Next Step For Human Spaceflight Recovery, Benjamin J. Johnis

Theses and Dissertations

Humans return to the Moon in 2024 under the NASA Artemis mission. Commercial space explorations are rapidly expanding. The sudden increase of human spaceflight calls for increased emphasis on space rescue. These revelations drove an AFRL/AFIT capability gap assessment to provide specific proposals for a modern space rescue program guided by Transaction Cost Economics Theory. The mission analysis arms USSPACECOM and NASA to coordinate an interagency approach to Lunar Search and Rescue, positioning America to compete in the new space race. The strategic consequences of failing to act could fundamentally jeopardize American leadership in space.

Uncertainty Quantification In Federated Learning For Persistent Post-Traumatic Headache, Byungmoo Brian Kim

Theses and Dissertations

A post-traumatic headache (PTH), resulting from a mild traumatic brain injury (mTBI), potentially develops into persistent post-traumatic headache (PPTH). Although no known cure for PPTH exists, research has shown that receiving treatment at earlier stages of PTH lowers the risk of patients developing PPTH. Previous studies have shown machine learning (ML) models capable of predicting a patient’s PTH progression, but none have considered the issue of protecting patient privacy. Due to patient privacy, ML models only have access to data within the institution. Federated learning (FL) harnesses data from separate institutions without sacrificing patient privacy as institutions can run ML …

Advancing Autonomous Swarm Behavior In A Simulated Anti-Access Area Denial (A2ad) Environment, Chad P. Macwilkinson

Theses and Dissertations

Advancements in modern IADS have bolstered A2AD environments and subsequently degraded the advantages that the Air Force once held, prompting a call to reform the nature of warfare in order to challenge these threats. A solution is weapon swarming technology, which has the ability to overwhelm IADS by engagement of a large numbers of low-cost, but lethal air assets that have autonomous functionalities. This research proposes the application of a four dimensional framework for autonomy to a swarm of cruise missiles. A virtual A2AD environment of two opposing forces is constructed using the AFSIM, wherein a manned bomber seeks to …

Predicting Success Of Pilot Training Candidates Using Interpretable Machine Learning, Alexandra S. King

Theses and Dissertations

The United States Air Force (USAF) has struggled with a sustained pilot shortage over the past several years; senior military and government leaders have been working towards a solution to the problem, with no noticeable improvements. Both attrition of more experienced pilots as well as wash out rates within pilot training contribute to this issue. This research focuses on pilot training attrition. Improving the process for selecting pilot candidates can reduce the number of candidates who fail. This research uses historical specialized undergraduate pilot training (SUPT) data and leverages select machine learning techniques to determine which factors are associated with …

Inducing Sparsity Within High-Dimensional Remote Sensing Modalities For Lightning Prediction, Grace E. Metzgar

Theses and Dissertations

The uncertainty of lightning constantly threatens many weather-sensitive fields where the slightest presence of lightning can endanger valuable personnel and assets. The consequences of delaying operations have incited the research of methods that can accurately predict the location of future lightning strikes from the current weather conditions. High-dimensional remote sensing modalities contain information capable of detecting significant patterns and intensities within storms that could indicate the presence of lightning. This thesis induces sparsity into convolutional neural networks (CNNs) and remote sensing modalities through a combination of regularization and tensor decomposition techniques to call attention to sparse features that are most …

Examining Failures Of Kc-135 Boom Assemblies Using Survival Analysis, Benjamin D. Miller

Theses and Dissertations

The purposes of this study are to confirm the applicability of survival analysis for predicting recurrent failures of a component of a military aircraft and to provide practical insights to maintenance managers and mission planners. The results of this study also can help the United States Department of Defense improve the CBM+ program. This study was able to predict recurrent failures of the component using Nelson-Aalen cumulative estimates. In addition, this study used a Cox proportional hazards regression model with shared frailty for measuring the effect of covariates on recurrent failures and unidentified heterogeneity in the model, which warranted future …

Simulation And Analysis Of Dynamic Threat Avoidance Routing In An Anti-Access Area Denial (A2ad) Environment, Dante C. Reid

Theses and Dissertations

This research modeled and analyzed the effectiveness of different routing algorithms for penetration assets in an A2AD environment. AFSIM was used with different configurations of SAMs locations and numbers to compare the performance of AFSIM’s internal zone and shrink algorithm routers with a Dijkstra algorithm router. Route performance was analyzed through computational and operational metrics, including computational complexity, run-time, mission survivability, and simulation duration. This research also analyzed the impact of the penetration asset’s ingress altitude on those factors. Additionally, an excursion was conducted to analyze the Dijkstra algorithm router’s grid density holding altitude constant to understand its impact on …