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Evaluating The Resiliency Of Industrial Internet Of Things Process Control Using Protocol Agnostic Attacks, Hector L. Roldan
Evaluating The Resiliency Of Industrial Internet Of Things Process Control Using Protocol Agnostic Attacks, Hector L. Roldan
Theses and Dissertations
Improving and defending our nation's critical infrastructure has been a challenge for quite some time. A malfunctioning or stoppage of any one of these systems could result in hazardous conditions on its supporting populace leading to widespread damage, injury, and even death. The protection of such systems has been mandated by the Office of the President of the United States of America in Presidential Policy Directive Order 21. Current research now focuses on securing and improving the management and efficiency of Industrial Control Systems (ICS). IIoT promises a solution in enhancement of efficiency in ICS. However, the presence of IIoT …
Nonlinear Characterizing Of A New Titanium Nitride On Aluminum Oxide Metalens, Michael A. Cumming
Nonlinear Characterizing Of A New Titanium Nitride On Aluminum Oxide Metalens, Michael A. Cumming
Theses and Dissertations
A sample metalens generated from Titanium Nitride deposited onto Aluminum Oxide was designed to focus at 10 microns with a beam centered at 800nm, and when analyzed with high intensity illumination was found to have a focal length of 9.650 ±.003µm at an intensity of 16.93[MW/cm2 ]. Analyzing this change by comparing it to a Fresnel Lens’ physics shows that for this lens, the effective nonlinear index of refraction is certainly greater than the nonlinear index of just Titanium Nitride itself, at −1.6239 × 10−15[m2/W] compared to the materials −1.3 × 10−15[m2 …
Numerical Simulation Of Unstable Laser Resonators With A High Gain Medium, Robert L. Lloyd
Numerical Simulation Of Unstable Laser Resonators With A High Gain Medium, Robert L. Lloyd
Theses and Dissertations
This research focused on the numeric simulation of unstable laser resonators with high gain media. In order to accomplish the research, the modes and eigenvalues for various bare cavity resonator were computed followed by modes of a resonator in the presence of gain. Using a Fourier Split Step Method in a Fox and Li iteration scheme, different laser outputs for various laser cavities with gain were computed. Various parameters defining positive branch confocal unstable resonators were chosen corresponding to four studies. The four studies focused on modifying laser cavity Fresnel number, gain medium parameters, gain cell position, and gain cell …
Statistical L-Moment And L-Moment Ratio Estimation And Their Applicability In Network Analysis, Timothy S. Anderson
Statistical L-Moment And L-Moment Ratio Estimation And Their Applicability In Network Analysis, Timothy S. Anderson
Theses and Dissertations
This research centers on finding the statistical moments, network measures, and statistical tests that are most sensitive to various node degradations for the Barabási-Albert, Erdös-Rényi, and Watts-Strogratz network models. Thirty-five different graph structures were simulated for each of the random graph generation algorithms, and sensitivity analysis was undertaken on three different network measures: degree, betweenness, and closeness. In an effort to find the statistical moments that are the most sensitive to degradation within each network, four traditional moments: mean, variance, skewness, and kurtosis as well as three non-traditional moments: L-variance, L-skewness, and L-kurtosis were examined. Each of these moments were …
Sample Size Requirements And Considerations For Models To Assess Human-Machine System Performance, Jennifer S. G. Lopez
Sample Size Requirements And Considerations For Models To Assess Human-Machine System Performance, Jennifer S. G. Lopez
Theses and Dissertations
Hierarchical Linear Models (HLMs), also known as multi-level models, are an extension of multiple regression analysis and can aid in the understanding of human and machine workloads of a system. These models allow for prediction and testing in systems with hierarchies of two or more levels. The complex interrelated variability of these multi-level models exists in operational settings, such as the Air Force Distributed Common Ground System Full Motion Video (AF DCGS FMV) community which is composed of individuals (Level-1), groups (Level-2), units (Level-3), and organizations (Level-4). Through the development of sample size requirements and considerations for multi-level models, this …
Digital Holography Efficiency Experiments For Tactical Applications, Douglas E. Thornton
Digital Holography Efficiency Experiments For Tactical Applications, Douglas E. Thornton
Theses and Dissertations
Digital holography (DH) uses coherent detection and offers direct access to the complex-optical field to sense and correct image aberrations in low signal-to-noise environments, which is critical for tactical applications. The performance of DH is compared to a similar, well studied deep-turbulence wavefront sensor, the self-referencing interferometer (SRI), with known efficiency losses. Wave optics simulations with deep-turbulence conditions and noise were conducted and the results show that DH outperforms the SRI by 10's of dB due to DH's strong reference. Additionally, efficiency experiments were conducted to investigate DH system losses. The experimental results show that the mixing efficiency (37%) is …
Targeted Germanium Ion Irradiation Of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistors, Melanie E. Mace
Targeted Germanium Ion Irradiation Of Aluminum Gallium Nitride/Gallium Nitride High Electron Mobility Transistors, Melanie E. Mace
Theses and Dissertations
Microscale beams of germanium ions were used to target different locations of aluminum galliumnitride/gallium nitride (AlGaN/GaN) high electron mobility transistors (HEMTs) to determine location dependent radiation effects. 1.7 MeV Ge ions were targeted at the gap between the gate and the drain to observe displacement damage effects while 47 MeV Ge ions were targeted at the gate to observe ionization damage effects. Electrical data was taken pre, during, and post irradiation. To separate transient from permanent degradation, the devices were characterized after a room temperature anneal for at least 30 days. Optical images were also analyzed pre and post irradiation. …
On The Pulsed Laser Ablation Of Metals And Semiconductors, Todd A. Van Woerkom
On The Pulsed Laser Ablation Of Metals And Semiconductors, Todd A. Van Woerkom
Theses and Dissertations
This dissertation covers pulsed laser ablation of Al, Si, Ti, Ge, and InSb, with pulse durations from tens of picosecond to hundreds of microseconds, fluences from ones of J/cm2 to over 10,000 J/cm2, and in ambient air and vacuum. A set of non-dimensional scaling factors was created to interpret the data relative to the laser and material parameters, and it was found that pulse durations shorter than a critical timescale formed craters much larger than the thermal diffusion length, and longer pulse durations created holes much shallower than the thermal diffusion length. Low transverse order Gaussian beams …
Dimension-Breaking For Traveling Waves In Interfacial Flows, Matthew W. Seiders
Dimension-Breaking For Traveling Waves In Interfacial Flows, Matthew W. Seiders
Theses and Dissertations
Fluid flow models in two spatial dimensions with a one-dimensional interface are known to support overturned traveling solutions. Computational methods of solving the two-dimensional problem are well developed, even in the case of overturned waves. The three-dimensional problem is harder for three prominent reasons. First, some formulations of the two-dimensional problem do not extend to three-dimensions. The technique of conformal mapping is a prime example, as it is very efficient in two dimensions but does not have a three-dimensional equivalent. Second, some three-dimensional models, such as the Transformed Field Expansion method, do not allow for overturned waves. Third, computational time …
Emergent Behavior Development And Control In Multi-Agent Systems, David W. King
Emergent Behavior Development And Control In Multi-Agent Systems, David W. King
Theses and Dissertations
Emergence in natural systems is the development of complex behaviors that result from the aggregation of simple agent-to-agent and agent-to-environment interactions. Emergence research intersects with many disciplines such as physics, biology, and ecology and provides a theoretical framework for investigating how order appears to spontaneously arise in complex adaptive systems. In biological systems, emergent behaviors allow simple agents to collectively accomplish multiple tasks in highly dynamic environments; ensuring system survival. These systems all display similar properties: self-organized hierarchies, robustness, adaptability, and decentralized task execution. However, current algorithmic approaches merely present theoretical models without showing how these models actually create hierarchical, …
Cocyclic Hadamard Matrices: An Efficient Search Based Algorithm, Jonathan S. Turner
Cocyclic Hadamard Matrices: An Efficient Search Based Algorithm, Jonathan S. Turner
Theses and Dissertations
This dissertation serves as the culmination of three papers. “Counting the decimation classes of binary vectors with relatively prime fixed-density" presents the first non-exhaustive decimation class counting algorithm. “A Novel Approach to Relatively Prime Fixed Density Bracelet Generation in Constant Amortized Time" presents a novel lexicon for binary vectors based upon the Discrete Fourier Transform, and develops a bracelet generation method based upon the same. “A Novel Legendre Pair Generation Algorithm" expands upon the bracelet generation algorithm and includes additional constraints imposed by Legendre Pairs. It further presents an efficient sorting and comparison algorithm based upon symmetric functions, as well …
The Trust-Based Interactive Partially Observable Markov Decision Process, Richard S. Seymour
The Trust-Based Interactive Partially Observable Markov Decision Process, Richard S. Seymour
Theses and Dissertations
Cooperative agent and robot systems are designed so that each is working toward the same common good. The problem is that the software systems are extremely complex and can be subverted by an adversary to either break the system or potentially worse, create sneaky agents who are willing to cooperate when the stakes are low and take selfish, greedy actions when the rewards rise. This research focuses on the ability of a group of agents to reason about the trustworthiness of each other and make decisions about whether to cooperate. A trust-based interactive partially observable Markov decision process (TI-POMDP) is …
Methodology For Comparison Of Algorithms For Real-World Multi-Objective Optimization Problems: Space Surveillance Network Design, Troy B. Dontigney
Methodology For Comparison Of Algorithms For Real-World Multi-Objective Optimization Problems: Space Surveillance Network Design, Troy B. Dontigney
Theses and Dissertations
Space Situational Awareness (SSA) is an activity vital to protecting national and commercial satellites from damage or destruction due to collisions. Recent research has demonstrated a methodology using evolutionary algorithms (EAs) which is intended to develop near-optimal Space Surveillance Network (SSN) architectures in the sense of low cost, low latency, and high resolution. That research is extended here by (1) developing and applying a methodology to compare the performance of two or more algorithms against this problem, and (2) analyzing the effects of using reduced data sets in those searches. Computational experiments are presented in which the performance of five …
Piezoelectric Sensor Crack Detection On Airframe Systems, Kevin J. Lin
Piezoelectric Sensor Crack Detection On Airframe Systems, Kevin J. Lin
Theses and Dissertations
In 2008, the Department of Defense published a guidebook for a methodology named Condition-Based Maintenance Plus (CBM+) which capabilities include improving productivity, shortening maintenance cycles, lowering costs, and increasing availability and reliability. This push replaces existing inspection criteria, often conducted as non-destructive testing (NDT), with structural health monitoring (SHM) systems. The SHM system addressed utilizes guided Lamb waves generated by piezoelectric wafer active sensors (PWAS) to detect the existence, size, and location of damage from through-thickness cracks around a rivet hole. The SHM field lacks an experiment testing how small changes in receiver sensor distances affect damage detection. In addition, …
Harmonic Equiangular Tight Frames Comprised Of Regular Simplices, Courtney A. Schmitt
Harmonic Equiangular Tight Frames Comprised Of Regular Simplices, Courtney A. Schmitt
Theses and Dissertations
An equiangular tight frame (ETF) is a sequence of equal-norm vectors in a Euclidean space whose coherence achieves equality in the Welch bound, and thus yields an optimal packing in a projective space. A regular simplex is a simple type of ETF in which the number of vectors is one more than the dimension of the underlying space. More sophisticated examples include harmonic ETFs, which are formed by restricting the characters of a finite abelian group to a difference set. Recently, it was shown that some harmonic ETFs are themselves comprised of regular simplices. In this thesis, we continue the …
Quantifying Uncertainty Of Ensemble Transport And Dispersion Simulations Using Hysplit, Daniel W. Bazemore
Quantifying Uncertainty Of Ensemble Transport And Dispersion Simulations Using Hysplit, Daniel W. Bazemore
Theses and Dissertations
Uncertainty associated with determining the source location of nuclear pollutants in the atmosphere after a nuclear fallout using a numerical model is difficult to determine. Uncertainty can originate from input data (meteorological and emissions), internal model error, physics parameterizations, and stochastic processes. This study uses the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with data from the 1983 Cross Appalachian Tracer Experiment (CAPTEX) (Ferber et al. 1986) and simulating six nuclear detonations (Rolph et al. 2014) to quantify and communicate uncertainty in ensemble dispersion simulations. This is accomplished by utilizing an ensemble of forward trajectory simulations varying initial conditions …
Development Of A Model For 11C Production Via The 14N(P,Α) Reaction Using A Ge Pettrace Cyclotron, Amy C. Hall
Development Of A Model For 11C Production Via The 14N(P,Α) Reaction Using A Ge Pettrace Cyclotron, Amy C. Hall
Theses and Dissertations
The GE PETtrace 800 Series cyclotron at the Missouri University Research Reactor (MURR) facility is used extensively for medical and research radioisotope production. However, no model exists of its radioisotope production performance, and the energy, full intensity, and spatial profile of the cyclotron proton beam has never been measured. To improve production planning for research and medical isotopes, a MCNP6 model of the isotope production process was developed to maximize efficiency in target design and better understand irradiation conditions. Since the cyclotron beam energy and profile has a significant impact on the types of reactions that take place and the …
Analysis Of The Gálvez-Davison Index For Convective Forecasting Over Africa Using The Galwem, William A. Hanson
Analysis Of The Gálvez-Davison Index For Convective Forecasting Over Africa Using The Galwem, William A. Hanson
Theses and Dissertations
From the hot, arid Sahara Desert to the humid, West African monsoon, Africa is a continent with vastly different weather and climate patterns from one region to the next. For this reason, thunderstorm forecasting over Africa has presented significant difficulty. The Gálvez-Davison Index (GDI) was developed for the Americas and provides a more accurate convective forecasting index than the conventional indices for thunderstorm forecasting, including the K, Total Totals, Showalter, and Lifted indices. Previous research using the GDI via the Global Forecasting System (GFS) model data over Africa showed promising results for areal coverage (Donndelinger 2018), especially during the spring …
Effects Of Sinusoidal Phase Modulation On Signal-To-Noise Ratio In A Digital Holography System, Davin Mao
Effects Of Sinusoidal Phase Modulation On Signal-To-Noise Ratio In A Digital Holography System, Davin Mao
Theses and Dissertations
Digital holography (DH) has been demonstrated to be an effective tool for tactical applications which involve in low signal-to-noise ratios (SNR). In practice, DH uses a strong reference beam from a local oscillator (LO) to scale SNR, however since DH relies on the interference of a signal beam with a mutually coherent LO, the coherence properties of the master oscillator (MO) can degrade system SNR for long range engagements. In this thesis, a digital holography system in the off-axis image plane recording geometry was assembled and used to measure the effects of the coherence properties of the MO on SNR. …
Comparing Dual-Polarization Radar Lightning Forecast Methods Across Southwest Utah, Daniel O. Katuzienski
Comparing Dual-Polarization Radar Lightning Forecast Methods Across Southwest Utah, Daniel O. Katuzienski
Theses and Dissertations
Lightning poses a significant hazard to space launch operations to include ground processing, launch window forecasts, and rocket-triggered lightning events. Two lightning initiation forecast methods using weather radar developed in Gremillion and Orville (1999) and Travis (2015) for Cape Canaveral Air Force Station (CCAFS) and Kennedy Space Center (KSC), Florida are tested in a new geographical region. This is accomplished by applying the highest-performing radar parameters from Gremillion and Orville (1999): reectivity (Z) ≥ 40 dBZ for two consecutive volume scans at the -10°C thermal height and Travis (2015): Z ≥ 36.5 dBZ with differential reflectivity (ZDR) ≥ 0.31 dB …
Coupled Atmospheric Surface Observations With Surface Aerosol Particle Counts For Daytime Sky Radiance Quantification, Scott S. Wolfmeyer
Coupled Atmospheric Surface Observations With Surface Aerosol Particle Counts For Daytime Sky Radiance Quantification, Scott S. Wolfmeyer
Theses and Dissertations
This study investigates the radiative transfer code, Laser Environmental Effects Definition and Reference (LEEDR), developed by the Center for Directed Energy at the Air Force Institute of Technology. Many multi- and hyperspectral applications are limited to the nighttime due in large part to daytime solar background noise and it is advantageous to be able to quantify this background noise using LEEDR. Real-time meteorological surface observations, numerical weather prediction, and aerosol particle concentrations were used to investigate the accuracy of LEEDR radiances simulations. Comparisons between simulations and measured values show that aerosol concentrations, weather predictions, and meteorological observations provide enough information …
Performance Analysis Of Angle Of Arrival Algorithms Applied To Radiofrequency Interference Direction Finding, Taylor S. Barber
Performance Analysis Of Angle Of Arrival Algorithms Applied To Radiofrequency Interference Direction Finding, Taylor S. Barber
Theses and Dissertations
Radiofrequency (RF) interference threatens the functionality of systems that increasingly underpin the daily function of modern society. In recent years there have been multiple incidents of intentional RF spectrum denial using terrestrial interference sources. Because RF based systems are used in safety-of-life applications in both military and civilian contexts, there is need for systems that can quickly locate these interference sources. In order to meet this need, the Air Force Research Laboratory Weapons Directorate is sponsoring the following research to support systems that will be able to quickly geolocate RF interferers using passive angle-of-arrival estimation to triangulate interference sources. This …
Confidence Inference In Defensive Cyber Operator Decision Making, Graig S. Ganitano
Confidence Inference In Defensive Cyber Operator Decision Making, Graig S. Ganitano
Theses and Dissertations
Cyber defense analysts face the challenge of validating machine generated alerts regarding network-based security threats. Operations tempo and systematic manpower issues have increased the importance of these individual analyst decisions, since they typically are not reviewed or changed. Analysts may not always be confident in their decisions. If confidence can be accurately assessed, then analyst decisions made under low confidence can be independently reviewed and analysts can be offered decision assistance or additional training. This work investigates the utility of using neurophysiological and behavioral correlates of decision confidence to train machine learning models to infer confidence in analyst decisions. Electroencephalography …
Near Real-Time Rf-Dna Fingerprinting For Zigbee Devices Using Software Defined Radios, Frankie A. Cruz
Near Real-Time Rf-Dna Fingerprinting For Zigbee Devices Using Software Defined Radios, Frankie A. Cruz
Theses and Dissertations
Low-Rate Wireless Personal Area Network(s) (LR-WPAN) usage has increased as more consumers embrace Internet of Things (IoT) devices. ZigBee Physical Layer (PHY) is based on the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 specification designed to provide a low-cost, low-power, and low-complexity solution for Wireless Sensor Network(s) (WSN). The standard’s extended battery life and reliability makes ZigBee WSN a popular choice for home automation, transportation, traffic management, Industrial Control Systems (ICS), and cyber-physical systems. As robust and versatile as the standard is, ZigBee remains vulnerable to a myriad of common network attacks. Previous research involving Radio Frequency-Distinct Native Attribute …
Instantaneous Bandwidth Expansion Using Software Defined Radios, Nicholas D. Everett
Instantaneous Bandwidth Expansion Using Software Defined Radios, Nicholas D. Everett
Theses and Dissertations
The Stimulated Unintended Radiated Emissions (SURE) process has been proven capable of classifying a device (e.g. a loaded antenna) as either operational or defective. Currently, the SURE process utilizes a specialized noise radar which is bulky, expensive and not easily supported. With current technology advancements, Software Defined Radios (SDRs) have become more compact, more readily available and significantly cheaper. The research here examines whether multiple SDRs can be integrated to replace the current specialized ultra-wideband noise radar used with the SURE process. The research specifically targets whether or not multiple SDR sub-band collections can be combined to form a wider …
Unguided Cyber Education Techniques Of The Non-Expert, Seth A. Martin
Unguided Cyber Education Techniques Of The Non-Expert, Seth A. Martin
Theses and Dissertations
The United States Air Force and Department of Defense continues to rely on its total workforce to provide the first layer of protection against cyber intrusion. Prior research has shown that the workforce is not adequately educated to perform this task. As a result, DoD cybersecurity strategy now includes attempting to improve education and training on cyber-related concepts and technical skills to all users of DoD networks. This paper describes an experiment designed to understand the broad methods that non-expert users may use to educate themselves on how to perform technical tasks. Preliminary results informed subsequent experiments that directly compared …
Testing The Fault Tolerance Of A Wide Area Backup Protection System Using Spin, Kenneth James
Testing The Fault Tolerance Of A Wide Area Backup Protection System Using Spin, Kenneth James
Theses and Dissertations
Cyber-physical systems are increasingly prevalent in daily life. Smart grids in particular are becoming more interconnected and autonomously operated. Despite the advantages, new challenges arise in the form of defending these assets. Recent studies reveal that small-scale, coordinated cyber-attacks on only a few substations across the U.S. could result in cascading failures affecting the entire nation. In support of defending critical infrastructure, this thesis tests the fault tolerance of a backup protection system. Each transmission line in the system incorporates autonomous agents which monitor the status of the line and make decisions regarding the safety of the grid. Various malfunctions …
A Blockchain-Based Anomalous Detection System For Internet Of Things Devices, Joshua K. Mosby
A Blockchain-Based Anomalous Detection System For Internet Of Things Devices, Joshua K. Mosby
Theses and Dissertations
Internet of Things devices are highly susceptible to attack, and owners often fail to realize they have been compromised. This thesis describes an anomalous-based intrusion detection system that operates directly on Internet of Things devices utilizing a custom-built Blockchain. In this approach, an agent on each node compares the node's behavior to that of its peers, generating an alert if they are behaving differently. An experiment is conducted to determine the effectiveness at detecting malware. Three different code samples simulating common malware are deployed against a testbed of 12 Raspberry Pi devices. Increasing numbers are infected until two-thirds of the …
Modeling The Distribution Of Lightning Strike Distances Outside A Preexisting Lightning Area, Dawn L. Sanderson
Modeling The Distribution Of Lightning Strike Distances Outside A Preexisting Lightning Area, Dawn L. Sanderson
Theses and Dissertations
Air Force Instruction 91-203 (AFI 91-203) directs that a lightning warning be issued when lightning is occurring or imminent within a 5 nautical mile (NM) radius of a predetermined location or activity. The 45 Weather Squadron (WS), located on the central eastern coast of Florida, balances the safety of personnel and space launch vehicles with lost productivity of taking shelter from lightning. The primary objective of this study investigates if this 5 NM safety radius can be reduced while maintaining a desired level of safety. The research uses processed Lightning Detection and Ranging (LDAR) data to map the movement of …
Global Ionosonde And Gps Radio Occultation Sporadic-E Intensity And Height Comparison, Joshua Y. Gooch
Global Ionosonde And Gps Radio Occultation Sporadic-E Intensity And Height Comparison, Joshua Y. Gooch
Theses and Dissertations
A global, multi-year comparison of low and mid-latitude COSMIC GPS radio occultation (RO) sporadic-E (Es) plasma frequency and altitude and Digisonde blanketing frequency (fbEs) and altitude within 150 km and 30 minutes of each other. RO methods used to estimate the intensity of the Es layer include the scintillation index S4, total electron content (TEC) with both a constant and variable Es cloud thickness, and an Abel transform. The S4 and TEC with varying thickness techniques both under-represent the fbEs values while the TEC with constant thickness and Abel transform better estimate Digisonde fbEs values. …