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Air Force Institute of Technology

Theses and Dissertations

2018

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Full-Text Articles in Physical Sciences and Mathematics

Electrical Characterization Of Crystalline Uo2, Tho2 And U0.71Th0.29O2, Christina L. Dugan Dec 2018

Electrical Characterization Of Crystalline Uo2, Tho2 And U0.71Th0.29O2, Christina L. Dugan

Theses and Dissertations

Uranium dioxide (UO2), thorium dioxide (ThO2), and UxTh1-xO2 alloys are characterized for suitability in uranium-based neutron detectors. ThO2 was studied for an envisioned UO2/ThO2 heterojunction. A U0.71Th0.29O2 alloy was studied because of its resistance to oxidation and potential use in surface passivation. The U0.71Th0.29O2 effective Debye temperature of 217± 24 K was measured using temperature-dependent x-ray photoemission spectroscopy (XPS). The specific heat capacity for the U0.71Th0.29O2 alloy was calculated from the Debye …

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Enabling Auditing And Intrusion Detection Of Proprietary Controller Area Networks, Brent C. Stone Dec 2018

Enabling Auditing And Intrusion Detection Of Proprietary Controller Area Networks, Brent C. Stone

Theses and Dissertations

The goal of this dissertation is to provide automated methods for security researchers to overcome ‘security through obscurity’ used by manufacturers of proprietary Industrial Control Systems (ICS). `White hat' security analysts waste significant time reverse engineering these systems' opaque network configurations instead of performing meaningful security auditing tasks. Automating the process of documenting proprietary protocol configurations is intended to improve independent security auditing of ICS networks. The major contributions of this dissertation are a novel approach for unsupervised lexical analysis of binary network data flows and analysis of the time series data extracted as a result. We demonstrate the utility …

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Kinetics Of Higher Lying Potassium States After Excitation Of The D2 Transition In The Presence Of Helium, Austin J. Wallerstein Dec 2018

Kinetics Of Higher Lying Potassium States After Excitation Of The D2 Transition In The Presence Of Helium, Austin J. Wallerstein

Theses and Dissertations

A kinetic model for the performance of a potassium Diode Pumped Alkali Laser (DPAL), including the role of higher lying states is developed to assess the impact on device efficiency and performance. A rate package for a nine level kinetic model including recommended rate parameters is solved under steady-state conditions. Energy pooling and far wing absorption populates higher lying states, with single photon and Penning ionization leading to modest potassium (K) dimer ion concentrations. The fraction of the population removed from the basic three levels associated with the standard model is less than 10% for all reasonable laser conditions, including …

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Improving Detection Of Dim Targets: Optimization Of A Moment-Based Detection Algorithm, Shannon R. Young Dec 2018

Improving Detection Of Dim Targets: Optimization Of A Moment-Based Detection Algorithm, Shannon R. Young

Theses and Dissertations

Wide area motion imagery (WAMI) sensor technology is advancing rapidly. Increases in frame rates and detector array sizes have led to a dramatic increase in the volume of data that can be acquired. Without a corresponding increase in analytical manpower, much of these data remain underutilized. This creates a need for fast, automated, and robust methods for detecting dim, moving signals of interest. Current approaches fall into two categories: detect-before-track (DBT) and track-before-detect (TBD) methods. The DBT methods use thresholding to reduce the quantity of data to be processed, making real time implementation practical but at the cost of the …

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Design And Optimization Of A 3-D Plasmonic Huygens Metasurface For Highly-Efficient Flat Optics, Bryan M. Adomanis Sep 2018

Design And Optimization Of A 3-D Plasmonic Huygens Metasurface For Highly-Efficient Flat Optics, Bryan M. Adomanis

Theses and Dissertations

For miniaturization of future USAF unmanned aerial and space systems to become feasible, accompanying sensor components of these systems must also be reduced in size, weight and power (SWaP). Metasurfaces can act as planar equivalents to bulk optics, and thus possess a high potential to meet these low-SWaP requirements. However, functional efficiencies of plasmonic metasurface architectures have been too low for practical application in the infrared (IR) regime. Huygens-like forward-scattering inclusions may provide a solution to this deficiency, but there is no academic consensus on an optimal plasmonic architecture for obtaining efficient phase control at high frequencies. This dissertation asks …

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Reconstruction Of The 3d Temperature And Species Concentration Spatial Distribution Of A Jet Engine Exhaust Plume Using An Infrared Fourier Transform Spectrometer Hyperspectral Imager, Mason D. Paulec Sep 2018

Reconstruction Of The 3d Temperature And Species Concentration Spatial Distribution Of A Jet Engine Exhaust Plume Using An Infrared Fourier Transform Spectrometer Hyperspectral Imager, Mason D. Paulec

Theses and Dissertations

The measurement of combustion byproducts is useful for determining pollution of any fuel burning application, efficiency of combustion, and determining detectability of aircraft exhausts. Both intrusive and non-intrusive techniques have been utilized to measure these quantities. For the majority of the non-intrusive techniques, the absorption and emission spectra of the gases are utilized for measurements. For this research, the use of the Telops Infrared Fourier Transform Spectrometer (IFTS) Hyperspectral Imager (HSI) was explored within the scope of combustion diagnostic methods, as an option for remote measurements of a jet turbine to determine concentration of species and temperature of the combustion …

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Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman Sep 2018

Application Of Spectral Solution And Neural Network Techniques In Plasma Modeling For Electric Propulsion, Joseph R. Whitman

Theses and Dissertations

A solver for Poisson's equation was developed using the Radix-2 FFT method first invented by Carl Friedrich Gauss. Its performance was characterized using simulated data and identical boundary conditions to those found in a Hall Effect Thruster. The characterization showed errors below machine-zero with noise-free data, and above 20% noise-to-signal strength, the error increased linearly with the noise. This solver can be implemented into AFRL's plasma simulator, the Thermophysics Universal Research Framework (TURF) and used to quickly and accurately compute the electric field based on charge distributions. The validity of a machine learning approach and data-based complex system modeling approach …

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Evaluation And Quantification Of Diffractive Plenoptic Camera Algorithm Performance, Jack A. Shepherd Iii Sep 2018

Evaluation And Quantification Of Diffractive Plenoptic Camera Algorithm Performance, Jack A. Shepherd Iii

Theses and Dissertations

A diffractive plenoptic camera is a novel approach to the traditional plenoptic camera which replaces the main optic with a Fresnel zone plate making the camera sensitive to wavelength instead of range. However, algorithms are necessary to reconstruct the image produced by plenoptic cameras. While many algorithms exist for traditional plenoptic cameras, their ability to create spectral images in a diffractive plenoptic camera is unknown. This paper evaluates digital refocusing, super resolution, and 3D deconvolution through a Richardson-Lucy algorithm as well as a new Gaussian smoothing algorithm. All of the algorithms worked well near the Fresnel zone plate design wavelength, …

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A Methodology For Evaluating Relational And Nosql Databases For Small-Scale Storage And Retrieval, Ryan D. Engle Sep 2018

A Methodology For Evaluating Relational And Nosql Databases For Small-Scale Storage And Retrieval, Ryan D. Engle

Theses and Dissertations

Modern systems record large quantities of electronic data capturing time-ordered events, system state information, and behavior. Subsequent analysis enables historic and current system status reporting, supports fault investigations, and may provide insight for emerging system trends. Unfortunately, the management of log data requires ever more efficient and complex storage tools to access, manipulate, and retrieve these records. Truly effective solutions also require a well-planned architecture supporting the needs of multiple stakeholders. Historically, database requirements were well-served by relational data models, however modern, non-relational databases, i.e. NoSQL, solutions, initially intended for “big data” distributed system may also provide value for smaller-scale …

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Breaking Down The Barriers To Operator Workload Estimation: Advancing Algorithmic Handling Of Temporal Non-Stationarity And Cross-Participant Differences For Eeg Analysis Using Deep Learning, Ryan G. Hefron Sep 2018

Breaking Down The Barriers To Operator Workload Estimation: Advancing Algorithmic Handling Of Temporal Non-Stationarity And Cross-Participant Differences For Eeg Analysis Using Deep Learning, Ryan G. Hefron

Theses and Dissertations

This research focuses on two barriers to using EEG data for workload assessment: day-to-day variability, and cross- participant applicability. Several signal processing techniques and deep learning approaches are evaluated in multi-task environments. These methods account for temporal, spatial, and frequential data dependencies. Variance of frequency- domain power distributions for cross-day workload classification is statistically significant. Skewness and kurtosis are not significant in an environment absent workload transitions, but are salient with transitions present. LSTMs improve day- to-day feature stationarity, decreasing error by 59% compared to previous best results. A multi-path convolutional recurrent model using bi-directional, residual recurrent layers significantly increases …

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Techniques For Improved Space Object Detection Performance From Ground-Based Telescope Systems Using Long And Short Exposure Images, David J. Becker Aug 2018

Techniques For Improved Space Object Detection Performance From Ground-Based Telescope Systems Using Long And Short Exposure Images, David J. Becker

Theses and Dissertations

Space object detection is of great importance in the highly dependent yet competitive and congested space domain. Detection algorithms employed play a crucial role in fulfilling the detection component in the space situational awareness mission to detect, track, characterize and catalog unknown space objects. Many current space detection algorithms use a matched filter or a spatial correlator on long exposure data to make a detection decision at a single pixel point of a spatial image based on the assumption that the data follows a Gaussian distribution. This research focuses on improving current space object detection algorithms and developing new algorithms …

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Compressive Sampling For Phenotype Classification, Eric L. Brooks Aug 2018

Compressive Sampling For Phenotype Classification, Eric L. Brooks

Theses and Dissertations

Phenotype classification has become an increasingly important genomic research method for disease identification and treatment. Phenotype classification is the investigation into the genetic information concerned with locating biomarkers (features) in order to identify an observed effect. The primary challenge associated with phenotype classification is with analyzing the data due to the inherent high-dimensionality of DNA data. As a result, phenotype classification faces challenges with feature selection, and consequently, classification accuracy. This research developed a methodology to alleviate these challenges while improving classification performance. The methodology leverages concepts of compressive sampling, to arrive at a process that identifies features most relevant …

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Numerical Simulation Of High Energy Laser Propagation, Dana F. Morrill Aug 2018

Numerical Simulation Of High Energy Laser Propagation, Dana F. Morrill

Theses and Dissertations

High energy lasers have many applications, such as in aerospace, weapons, wireless power transfer, and manufacturing. Fluid-laser interaction is important to predicting power at receiver, and other measures of laser beam quality. Typically the carrying medium of the laser is modeled statistically. This dissertation describes a novel method of coupling fluid dynamics to beam propagation in free space. The coupled laser-fluid solver captures dynamic interaction of fluid temperature and beam intensity. Ultimately, the model captures the effects of fluid convection in the laser intensity-field. Boundary conditions play an important role for fluid dynamics, more so than for beam dynamics. Simulation …

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Statistical Inference To Evaluate And Compare The Performance Of Correlated Multi-State Classification Systems, Beau A. Nunnally Aug 2018

Statistical Inference To Evaluate And Compare The Performance Of Correlated Multi-State Classification Systems, Beau A. Nunnally

Theses and Dissertations

The current emphasis on including correlation when comparing diagnostic test performance is quite important, however, there are cases in which correlation effects may be negligible with respect to inference. This proposed work examines the impact of including correlation between classification systems with continuous features by comparing the optimal performance of two diagnostic tests with multiple outcomes as well as providing inference for a sequence of tests. We define the optimal point using Bayes Cost, a metric that sums the weighted misclassifications within a diagnostic test using a cost/benefit structure. Through simulation, we quantify the impact of correlation on standard errors …

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Automating Mobile Device File Format Analysis, Richard A. Dill Aug 2018

Automating Mobile Device File Format Analysis, Richard A. Dill

Theses and Dissertations

Forensic tools assist examiners in extracting evidence from application files from mobile devices. If the file format for the file of interest is known, this process is straightforward, otherwise it requires the examiner to manually reverse engineer the data structures resident in the file. This research presents the Automated Data Structure Slayer (ADSS), which automates the process to reverse engineer unknown file for- mats of Android applications. After statically parsing and preparing an application, ADSS dynamically runs it, injecting hooks at selected methods to uncover the data structures used to store and process data before writing to media. The resultant …

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Effects Of Dynamic Goals On Agent Performance, Nathan R. Ball Jun 2018

Effects Of Dynamic Goals On Agent Performance, Nathan R. Ball

Theses and Dissertations

Autonomous systems are increasingly being used for complex tasks in dynamic environments. Robust automation needs to be able to establish its current goal and determine when the goal has changed. In human-machine teams autonomous goal detection is an important component of maintaining shared situational awareness between both parties. This research investigates how different categories of goals affect autonomous change detection in a dynamic environment. In order to accomplish this goal, a set of autonomous agents were developed to perform within an environment with multiple possible goals. The agents perform the environmental task while monitoring for goal changes. The experiment tests …

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Efficient Phase Retrieval For Off-Axis Point Spread Functions, Salome Esteban Carrasco Jun 2018

Efficient Phase Retrieval For Off-Axis Point Spread Functions, Salome Esteban Carrasco

Theses and Dissertations

A novel pairing of phase retrieval tools allows for efficient estimation of pupil phase in optical systems from images of point spread functions (PSFs). The phase retrieval algorithm uses correlation of modeled phase in the focal plane to decouple aberrations that are difficult to identify in complex PSFs. The use of a phase kernel that departs from the Fresnel approximation for off-axis PSFs is a more accurate representation of wavefront phase in finite conjugate imaging. The combination of the approximation and phase correlation algorithm can be more efficient and accurate than generic algorithms.

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Investigation Of Scramjet Flowfield Temperatures At The Boundary Layer With Hyperspectral Imaging, Amy M. Kerst Jun 2018

Investigation Of Scramjet Flowfield Temperatures At The Boundary Layer With Hyperspectral Imaging, Amy M. Kerst

Theses and Dissertations

Within the domain of chemical propulsion, the fields of combustion diagnostics and computational fluid dynamics each have a long history, and both have led to a better understanding of complex phenomena yielding practical improvements in propulsion systems. As more exotic forms of propulsion are developed, the importance of -- and often the challenges with -- both diagnostic and simulation capabilities also increase. In the case of scramjet combustion, these challenges primarily arise from the highly turbulent environment in the combustion cavity, and the high-speed, compressible nature of the flowfield. Efforts are underway to develop computer models of scramjet combustion environments …

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Improving Annual Fixed Wing Maintenance Cost Estimates Through Cost Estimating Relationships, Kirsten Bunecke Mar 2018

Improving Annual Fixed Wing Maintenance Cost Estimates Through Cost Estimating Relationships, Kirsten Bunecke

Theses and Dissertations

The Air Force executes its mission primarily through the use of fixed-wing aircrafts. Maintaining these aircrafts represents approximately one-third of annual Operating and Support costs; which in turn, make up the majority of Life Cycle Costs. The current approach to estimating aircraft maintenance costs does not take into consideration programmatic data available in the Air Force Total Ownership Cost (AFTOC) database. The four maintenance cost subcategories researched in this thesis are Consumable Materials and Repair Parts, Depot Level Repairables (DLRs), Depot Maintenance, and Contractor Logistic Support. Each of these cost categories must first be standardized to be able to compare …

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The Impact Of Changing Requirements, James C. Ellis Mar 2018

The Impact Of Changing Requirements, James C. Ellis

Theses and Dissertations

The fundamental purpose of an Engineering Change Proposal (ECP) is to change the requirements of a contract. To build in flexibility, the acquisition practice is to estimate a dollar value to hold in reserve after the contract is awarded. There appears to be no empirical-based method for estimating this ECP withhold in the literature. Using the Cost Assessment Data Enterprise (CADE) database, 533 contracts were randomly selected to build two regression models: one to predict the likelihood of a contract experiencing an ECP, and the other to determine the expected median percent increase in baseline contract cost if an ECP …

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Simulation And Modeling Of High Energy Laser-Induced Droplet Shattering In Clouds, Andrew P. Lawrence Mar 2018

Simulation And Modeling Of High Energy Laser-Induced Droplet Shattering In Clouds, Andrew P. Lawrence

Theses and Dissertations

The process of a megawatt laser passing through a cloud is modeled. Specifically, the potential for droplet shattering is explored as a method for clearing a path through a cloud through which a second laser may be sent unobstructed. The paraxial approximation, an approximation to Maxwell's equations, is used to model the beam propagation. The simplified cloud model has assumed a distribution of pure, timescale restricted, droplets evenly distributed with uniform radius and initial temperature. All of the radiative heating is assumed to heat the droplet, neglecting radius change and vaporization based upon characteristic time scales. A 1+1 dimensional model …

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A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger Mar 2018

A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger

Theses and Dissertations

Severe wind gusts and thunderstorms have been difficult to forecast in Africa. Traditional convective forecast tools (e.g. Total Totals Index, Lifted Index, K Index (KI) and Convective Available Potential Energy) do not accurately portray potential for thunderstorms in Africa. This research effort used the Gálvez-Davison Index (GDI), a convective index created for the tropics, and assess its applicability to northern Africa. GDI was produced for the Caribbean and Central America, and utilized temperature, moisture, mid-level stability, dry air entrainment and an elevation factor to calculate convective potential. In this research, GDI and KI were calculated using Global Forecast System (GFS) …

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Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman Mar 2018

Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman

Theses and Dissertations

As technology continues to advance the domain of cyber defense, signature and heuristic detection mechanisms continue to require human operators to make judgements about the correctness of machine decisions. Human cyber defense operators rely on their experience, expertise, and understanding of network security, when conducting cyber-based investigations, in order to detect and respond to cyber alerts. Ever growing quantities of cyber alerts and network traffic, coupled with systemic manpower issues, mean no one has the time to review or change decisions made by operators. Since these cyber alert decisions ultimately do not get reviewed again, an inaccurate decision could cause …

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Pattern-Of-Life Modeling Using Data Leakage In Smart Homes, Steven M. Beyer Mar 2018

Pattern-Of-Life Modeling Using Data Leakage In Smart Homes, Steven M. Beyer

Theses and Dissertations

This work investigates data leakage in smart homes by providing a Smart Home Automation Architecture (SHAA) and a device classifier and pattern-of-life analysis tool, CITIoT (Classify, Identify, and Track Internet of things). CITIoT was able to capture traffic from SHAA and classify 17 of 18 devices, identify 95% of the events that occurred, and track when users were home or away with near 100% accuracy. Additionally, a mitigation tool, MIoTL (Mitigation of IoT Leakage) is provided to defend against smart home data leakage. With mitigation, CITIoT was unable to identify motion and camera devices and was inundated with an average …

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The Application Of Text Mining And Data Visualization Techniques To Textual Corpus Exploration, Jeffrey R. Smith Jr. Mar 2018

The Application Of Text Mining And Data Visualization Techniques To Textual Corpus Exploration, Jeffrey R. Smith Jr.

Theses and Dissertations

Unstructured data in the digital universe is growing rapidly and shows no evidence of slowing anytime soon. With the acceleration of growth in digital data being generated and stored on the World Wide Web, the prospect of information overload is much more prevalent now than it has been in the past. As a preemptive analytic measure, organizations across many industries have begun implementing text mining techniques to analyze such large sources of unstructured data. Utilizing various text mining techniques such as n -gram analysis, document and term frequency analysis, correlation analysis, and topic modeling methodologies, this research seeks to develop …

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Near Earth Space Object Detection Utilizing Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins Mar 2018

Near Earth Space Object Detection Utilizing Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins

Theses and Dissertations

The US Strategic Command (USSTRATCOM) operated Space Surveillance Network (SSN) is tasked with Space Situational Awareness (SSA) for the US military. This system is made up of Electro-Optic sensors such as the Space Surveillance Telescope (SST) and Ground-based Electro-Optical Deep Space Surveillance (GEODSS) as well as RADAR based sensors such as the Space Fence. While Lockheed Martin’s Space Fence is very adept at detecting & tracking objects in Low Earth Orbit (LEO) below 3000 Km in height [1], gaps remain in the tracking of Resident Space Objects (RSO’s) in Geosynchronous Orbits (GEO) due to limitations associated with the implementation of …

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Characterization Of The Effects Of Heavy Charged Particle Exposure On The Radiation Resistant Bacterium Deinococcus Radiodurans, Todd A. Bryant Mar 2018

Characterization Of The Effects Of Heavy Charged Particle Exposure On The Radiation Resistant Bacterium Deinococcus Radiodurans, Todd A. Bryant

Theses and Dissertations

Although not an extremophile, Deinococcus radiodurans has proven to have exceptional resistance to ionizing radiation, specifically via gamma and X-ray photons. To date, no known experiments have bombarded the bacterium with charged particles larger than hydrogen. This study explored the effects on the organism’s ability to survive high linear energy transfer heavy-charged particle exposures of oxygen ions. It also investigated the effects of low linear energy transfer ultraviolet radiation on various mutants. Two uvrB mutants were created to ascertain the importance of the gene in single-strand break repair following gamma irradiation and two recF mutants were created to explore the …

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Impacts Of Sub-Auroral Polarization Streams On High Frequency Operations As A Function Of Modeled Particle Energy Flux, Nathan D. Smith Mar 2018

Impacts Of Sub-Auroral Polarization Streams On High Frequency Operations As A Function Of Modeled Particle Energy Flux, Nathan D. Smith

Theses and Dissertations

Space weather events can cause irregularities within the ionosphere; in particular, this research examines sub-auroral polarization streams (SAPS), as their accompanying irregularities and effects can degrade high-frequency (HF) signal propagation. It is known that the strongest westerly current drifts delineating SAPS are associated with a deep ionospheric trough, which in turn contaminates HF data with clutter from the non-standard ionosphere. Having a methodology to track and identify these occurrences on current computational architecture would provide operators enhanced situational awareness in knowing to expect degradation in HF processes. This study has discovered a weak, yet significant, exponentially decaying correlation between maximum …

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A Comparison Of High Frequency Angle Of Arrival And Ionosonde Data During A Traveling Ionospheric Disturbance, Kalen L. Knippling Mar 2018

A Comparison Of High Frequency Angle Of Arrival And Ionosonde Data During A Traveling Ionospheric Disturbance, Kalen L. Knippling

Theses and Dissertations

High Frequency (HF) geolocation techniques are commonly used to track the source of uncooperative HF emitters. A traveling ionospheric disturbance (TID) makes geolocation particularly difficult due to large perturbations in the local ionospheric electron density profile. Angle of Arrival (AoA) and ionosonde virtual height measurements collected at White Sands Missile Range, New Mexico in January 2014, are analyzed during a medium scale traveling ionospheric disturbance. TID characteristics are extracted from the measurements, and a comparison between the data sets is per- formed to provide a measure of correlation as a function of distance and time between the ionosonde and AoA …

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Shortest Path Across Stochastic Network With Correlated Random Arcs, Stephanie M. Boone Mar 2018

Shortest Path Across Stochastic Network With Correlated Random Arcs, Stephanie M. Boone

Theses and Dissertations

This paper introduces a new approach to identify the shortest path across a stochastic network with correlated random arcs utilizing nonparametric samples of arc lengths. This approach is applied to find optimal aircraft routes that minimize expected fuel consumption for a given airspeed utilizing predicted wind output from NWP ensemble models. Results from this new methodology are then compared to the current fuel minimization route planning method that utilizes deterministic NWP wind data for arc lengths. Comparisons are also made to other previously proposed alternative fuel minimization methodologies that utilize mean and median wind data calculated from NWP ensemble wind …

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