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Air Force Institute of Technology

Theses and Dissertations

Theses/Dissertations

2017

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Understanding And Developing Estimates Based On Practical Foundation Methods For Alaska's Discontinuous Permafrost Region, Paul P. Dennison Dec 2017

Understanding And Developing Estimates Based On Practical Foundation Methods For Alaska's Discontinuous Permafrost Region, Paul P. Dennison

Theses and Dissertations

This research uses a quantitative analysis to develop a family of curves and a calculator for potential foundation thresholds in the discontinuous permafrost region of Alaska. The United States Pacific Command (PACAF) is bolstering the region by advocating for the F-35, KC-46, and the newly proposed long-range bomber to be stationed in Alaska. These next generation aircrafts and warfighters will need new facilities and beddown plans to efficiently and effectively carry out their mission. The biggest obstacle in the region is permafrost; this unique polar phenomenon is found throughout the northern half of Alaska. Fairbanks in particular has multiple military …


Characterization And Scaling Study Of Energy Pathways In Small Four-Stroke Internal Combustion Engines, Jason R. Blantin Sep 2017

Characterization And Scaling Study Of Energy Pathways In Small Four-Stroke Internal Combustion Engines, Jason R. Blantin

Theses and Dissertations

A study of the efficiency and energy losses of a selection of five small (40 - 200 cm3 displacement) single cylinder, four-stroke engines was accomplished. The study was performed as part of a larger effort to improve the range and endurance of small internal combustion engines (ICE) that power Group II Unmanned Aerial Vehicles (UAVs). Little is known about the performance, efficiency, and allocation of energy losses for four-stroke ICEs in this size range. The goal of the study was to characterize these parameters for use in future research efforts. Three research objectives were developed to guide the study …


Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens Sep 2017

Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens

Theses and Dissertations

Quantifying an expected improvement when considering moderate-complexity changes to a process is time consuming and has potential to overlook stochastic effects. By modeling a process as a Numerical Design Structure Matrix (NDSM), simulating the proposed changes, and evaluating performance, quantification can be rapidly accomplished to understand stochastic effects. This thesis explores a method to evaluate complex process changes within Six Sigma DMAIC process improvement to identify the most desirable outcome amongst several improvement options. A tool to perform the modeling and evaluation is developed. This process evaluation tool is verified for functionality, then is demonstrated against generic processes, a case …


Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel Sep 2017

Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel

Theses and Dissertations

Carbon fiber reinforced polymer manufactured using additive manufacturing process is relatively a new process. The ability to predict the mechanical properties of these parts with high confidence will spread the use of these high-strength materials in more applications. The purpose of this research was to determine the effect of the build time between successive layers, arrangement of fiber and nylon layers, fiber start location, and the use of support material on the mechanical properties CFRP produced by additive manufacturing process using the MarkForged (MarkOne) 3D printer. A design of experiment (DOE) we preformed to develop a mathematical model describing the …


Laser Heating Of Graphite And Pulsed Laser Ablation Of Titanium And Aluminum, William A. Bauer Sep 2017

Laser Heating Of Graphite And Pulsed Laser Ablation Of Titanium And Aluminum, William A. Bauer

Theses and Dissertations

Tactical missions for laser weapons include a wide variety of targets, increasing the demands on the laser lethality community. New approaches to reducing the dimensionality of laser and materials interactions are necessary to increase predictive capability. Self-contained systematic experimental study was conducted on continuous wave and pulsed laser interaction with graphite, Al, and Ti. The spectroscopy and plume dynamics from the heating and ablation of these materials was examined to characterize laser weapons effects, develop graphite response for thermal protection systems, and provide optical diagnostics for materials processing. Furthermore, analysis of ablated plume velocity distributions shows application of conventional Maxwell-Boltzmann …


Analysis Of Ar(1s5) Metastable Populations In High Pressure Argon-Helium Gas Discharges, Daniel J. Emmons Ii Sep 2017

Analysis Of Ar(1s5) Metastable Populations In High Pressure Argon-Helium Gas Discharges, Daniel J. Emmons Ii

Theses and Dissertations

Simulations of an argon-helium plasma are performed for two high pressure discharge scenarios to find a uniform, large-volume plasma with Ar(1s5) metastable densities on the order of 1013 cm-3 for use as the ground state in an optically pumped rare gas laser. An analysis of a pulsed direct current discharge is performed for a 7% argon in helium mixture at a pressure of 270 Torr using both zero and one-dimensional models. Kinetics of species relevant to the operation of an optically pumped rare gas laser are analyzed throughout the pulse duration to identify key reaction pathways. Simulations are …


A Tree Locality-Sensitive Hash For Secure Software Testing, Camdon J. Cady Sep 2017

A Tree Locality-Sensitive Hash For Secure Software Testing, Camdon J. Cady

Theses and Dissertations

Bugs in software that make it through testing can cost tens of millions of dollars each year, and in some cases can even result in the loss of human life. In order to eliminate bugs, developers may use symbolic execution to search through possible program states looking for anomalous states. Most of the computational effort to search through these states is spent solving path constraints in order to determine the feasibility of entering each state. State merging can make this search more efficient by combining program states, allowing multiple execution paths to be analyzed at the same time. However, a …


A Stochastic Model Of Plausibility In Live-Virtual-Constructive Environments, Jeremy R. Millar Sep 2017

A Stochastic Model Of Plausibility In Live-Virtual-Constructive Environments, Jeremy R. Millar

Theses and Dissertations

Distributed live-virtual-constructive simulation promises a number of benefits for the test and evaluation community, including reduced costs, access to simulations of limited availability assets, the ability to conduct large-scale multi-service test events, and recapitalization of existing simulation investments. However, geographically distributed systems are subject to fundamental state consistency limitations that make assessing the data quality of live-virtual-constructive experiments difficult. This research presents a data quality model based on the notion of plausible interaction outcomes. This model explicitly accounts for the lack of absolute state consistency in distributed real-time systems and offers system designers a means of estimating data quality and …


A Location-Aware Middleware Framework For Collaborative Visual Information Discovery And Retrieval, Andrew J.M. Compton Sep 2017

A Location-Aware Middleware Framework For Collaborative Visual Information Discovery And Retrieval, Andrew J.M. Compton

Theses and Dissertations

This work addresses the problem of scalable location-aware distributed indexing to enable the leveraging of collaborative effort for the construction and maintenance of world-scale visual maps and models which could support numerous activities including navigation, visual localization, persistent surveillance, structure from motion, and hazard or disaster detection. Current distributed approaches to mapping and modeling fail to incorporate global geospatial addressing and are limited in their functionality to customize search. Our solution is a peer-to-peer middleware framework based on XOR distance routing which employs a Hilbert Space curve addressing scheme in a novel distributed geographic index. This allows for a universal …


Biologically Inspired Network (Bionet) Authentication Using Logical And Pathological Rf-Dna Credential Pairs, Tyrone A.L. Lewis Sr. Sep 2017

Biologically Inspired Network (Bionet) Authentication Using Logical And Pathological Rf-Dna Credential Pairs, Tyrone A.L. Lewis Sr.

Theses and Dissertations

The command and control (C2) of shared space resources are vulnerable to logical credential forgery and impersonation attacks among standardized and interoperable wireless radio frequency (RF) networks. Threats could come from trusted operators (insiders) or from external sources (outsiders). An attacker may gain unauthorized network access and illegally cross into C2 boundaries when conventional network authentication fails. This research proposes an integrated trust management system that uses both application-layer and physical-layer trust markers to authenticate users and their communication sources. In essence, the results from physical-layer RF-DNA fingerprinting techniques are used to improve application-level trust schemes based on command patterns, …


Engineered Surfaces To Control Secondary Electron Yield For Multipactor Suppression, James M. Sattler Sep 2017

Engineered Surfaces To Control Secondary Electron Yield For Multipactor Suppression, James M. Sattler

Theses and Dissertations

A significant problem for satellites, vacuum electron devices, and particle accelerators is multipactor: an avalanche of electrons caused by recurring secondary electron emission (SEE) in a time-varying electric field. The consequences of multipactor range from temporary to permanent device failure. This research studied how surface topography can be engineered to minimize SEE and suppress multipactor. Two new semi-empirical models (one based on a 2D pore, the other based on a 3D pore) were developed to predict the secondary electron yield (SEY) of a porous surface based on pore aspect ratio and porosity. The models were validated with experimental SEY measurements …


Special Features Of The Air-To-Space Neutron Transport Problem, Whitman T. Dailey Sep 2017

Special Features Of The Air-To-Space Neutron Transport Problem, Whitman T. Dailey

Theses and Dissertations

Special features of the air-to-space neutron transport problem are identified, characterized, and quantified to provide information on features that should be included in Monte Carlo simulations to obtain accurate predictions. Currently available codes and tools for Monte Carlo neutron transport calculations do not provide an adequate (in accuracy nor precision nor efficiency) framework for practical transport calculations in the context of the air-to-space neutron transport problem. A new Fortran code, High Altitude Transport to Space for Neutrons (HATS-n), is developed and tested to perform high fidelity Monte Carlo neutron transport calculations for this class of problems. Special features of the …


Oblique Longwave Infrared Atmospheric Compensation, Daniel S. O'Keefe Sep 2017

Oblique Longwave Infrared Atmospheric Compensation, Daniel S. O'Keefe

Theses and Dissertations

This research introduces two novel oblique longwave infrared atmospheric compensation techniques for hyperspectral imagery, Oblique In-Scene Atmospheric Compensation (OISAC) and Radiance Detrending (RD). Current atmospheric compensation algorithms have been developed for nadir-viewing geometries which assume that every pixel in the scene is affected by the atmosphere in nearly the same manner. However, this assumption is violated in oblique imaging conditions where the transmission and path radiance vary continuously as a function of object-sensor range, negatively impacting current algorithms in their ability to compensate for the atmosphere. The techniques presented here leverage the changing viewing conditions to improve rather than hinder …


Luminescence In Lithium Borates, Brant T. Kananen Sep 2017

Luminescence In Lithium Borates, Brant T. Kananen

Theses and Dissertations

Spectrometry methods are used to identify and characterize point defects in single crystals of lithium tetraborate (Li2B4O7) and lithium triborate (LiB3O5) doped with silver or copper, and explore the role of these point defects in luminescence. New defects are identified in Ag-doped including: lithium vacancy substitutional-silver-ion defect-pairs (hole trap); isolated lithium vacancies (hole trap); isolated oxygen vacancies (electron trap); interstitial-silver-ion substitutional-silver-ion defect pairs (electron trap); isolated interstitial silver ions (electron trap); and interstitial-silver-ion lithium-vacancy defect pairs (electron trap). Defect models are proposed, and adjustments made to defect models known defects. …


Characterization Of Jet Fuel Combustion Emissions During A C-130 Aeromedical Evacuation Engines Running Onload, Michelle L. Page Sep 2017

Characterization Of Jet Fuel Combustion Emissions During A C-130 Aeromedical Evacuation Engines Running Onload, Michelle L. Page

Theses and Dissertations

The purpose of this research was to characterize jet fuel combustion emissions (JFCE) in an occupational setting. Prior research demonstrated that aircraft emit hazardous species, especially at engine start-up and ground idle. Complaints of eye, nose, and throat irritation from occupational exposures near aircraft exist. In this study JFCE were tested during an aeromedical evacuation engines running patient onload (ERO) on a C-130 Hercules at the 179th Airlift Wing, Mansfield-Lahm Air National Guard. Ultrafine particles, VOC, formaldehyde, carbon monoxide (CO), sulfuric acid, and metals were sampled simultaneously in approximate crew and patient breathing zones. Testing methods were portable condensation …


Dynamics Of Chemical Degradation In Water Using Photocatalytic Reactions In An Ultraviolet Light Emitting Diode Reactor, John E. Stubbs Sep 2017

Dynamics Of Chemical Degradation In Water Using Photocatalytic Reactions In An Ultraviolet Light Emitting Diode Reactor, John E. Stubbs

Theses and Dissertations

This work examined ultraviolet (UV) light emitting diodes (LED) and hydrogen peroxide in an advanced oxidation process in support of a USAF installation net zero water initiative. A UV LED reactor was used for degradation of soluble organic chemicals. There were linear relationships between input drive current, optical output power, and first order degradation rate constants. When drive current was varied, first order degradation rates depended on chemical identities and the drive current. When molar peroxide ratios were varied, kinetic profiles revealed peroxide-limited or radical-scavenged phenomena. Molar absorptivity helped explain the complexity of chemical removal profiles. Degradation kinetics were used …


Three-Dimensional Imaging Of Cold Atoms In A Magneto-Optical Trap With A Light Field Microscope, Gordon E. Lott Sep 2017

Three-Dimensional Imaging Of Cold Atoms In A Magneto-Optical Trap With A Light Field Microscope, Gordon E. Lott

Theses and Dissertations

Imaging of trapped atoms in three dimensions utilizing a light field microscope is demonstrated in this work. Such a system is of interest in the development of atom interferometer accelerometers in dynamic systems where strictly defined focal planes may be impractical. A light field microscope was constructed utilizing a Lytro® Development Kit micro-lens array and sensor. It was used to image fluorescing rubidium atoms in a magneto-optical trap. The three-dimensional (3D) volume of the atoms is reconstructed using a modeled point spread function (PSF), taking into consideration the low magnification (1.25) of the system which changed typical assumptions in the …


Satellite Propulsion Spectral Signature Detection And Analysis For Space Situational Awareness Using Small Telescopes, Pamela L. Wheeler Aug 2017

Satellite Propulsion Spectral Signature Detection And Analysis For Space Situational Awareness Using Small Telescopes, Pamela L. Wheeler

Theses and Dissertations

Safe satellite operations are of utmost importance. Maintaining precise orbital maintenance places stringent performance requirements on current propulsion systems, which are often electric propulsion systems. Electron temperature is a commonly used diagnostic to determine the performance of a Hall thruster, and recent work has correlated near infrared (NIR) spectral measurements of ionization lines of xenon and krypton to electron temperature measurements. In the research herein, appropriate line spectra ratios are identified for each propellant type when used with remote space-to-ground observations. NIR plume emissions were used to characterize a 600 Watt Hall thruster for a variety of observation angles and …


Optimal Control Methods For Missile Evasion, Ryan W. Carr Jul 2017

Optimal Control Methods For Missile Evasion, Ryan W. Carr

Theses and Dissertations

Optimal control theory is applied to the study of missile evasion, particularly in the case of a single pursuing missile versus a single evading aircraft. It is proposed to divide the evasion problem into two phases, where the primary considerations are energy and maneuverability, respectively. Traditional evasion tactics are well documented for use in the maneuverability phase. To represent the first phase dominated by energy management, the optimal control problem may be posed in two ways, as a fixed final time problem with the objective of maximizing the final distance between the evader and pursuer, and as a free final …


Improved Atmospheric Characterization For Hyperspectral Exploitation, Nathan P. Wurst Jun 2017

Improved Atmospheric Characterization For Hyperspectral Exploitation, Nathan P. Wurst

Theses and Dissertations

Airborne hyperspectral imaging (HSI) in the LWIR has shown utility in material detection and identification. This research seeks to determine the most effective methods to perform model-based atmospheric compensation of LWIR HSI data by comparing results obtained from different atmospheric profiles. The standard model for mid-latitude summer (MLS) and radiosonde data are compared to the National Operational Model Archive and Distribution System (NOMADS) numerical weather predictions and the Extreme and Percentile Environmental Reference Tables (ExPERT). The two latter atmospheric profiles are generated using the Laser Environmental Effects Definition and Reference (LEEDR) software. MLS has been a standard starting point for …


Analysis Of An Experimental Space Debris Removal Mission, Krista L.L. Roth Jun 2017

Analysis Of An Experimental Space Debris Removal Mission, Krista L.L. Roth

Theses and Dissertations

Encountering space debris is an ever-increasing problem in space exploration and exploitation, especially in Low Earth Orbit. While many space-faring governing bodies have attempted to control the orbital lifetime post mission completion of satellites and rocker bodies, objects already in orbit pose a danger to future mission planning. Currently, governments and academic institutions are working to develop missions to remove space debris; however, the proposed missions are typically costly primary missions. This research proposes an alternative to use an upper stage rocket, to be called a chaser, already launching a primary mission near the desired debris as a host for …


Applying Cyber Threat Intelligence To Industrial Control Systems, Matthew P. Sibiga Mar 2017

Applying Cyber Threat Intelligence To Industrial Control Systems, Matthew P. Sibiga

Theses and Dissertations

A cybersecurity initiative known as cyber threat intelligence (CTI) has recently been developed and deployed. The overall goal of this new technology is to help protect network infrastructures. Threat intelligence platforms (TIPs) have also been created to help facilitate CTI effectiveness within organizations. There are many benefits that both can achieve within the information technology (IT) sector. The industrial control system (ICS) sector can also benefit from these technologies as most ICS networks are connected to IT networks. CTI and TIPs become resourceful when using indicators of compromise (IOCs) from known ICS malware attacks and an open source intrusion detection …


Small Fixed-Wing Aerial Positioning Using Inter-Vehicle Ranging Combined With Visual Odometry, Benjamin M. Fain Mar 2017

Small Fixed-Wing Aerial Positioning Using Inter-Vehicle Ranging Combined With Visual Odometry, Benjamin M. Fain

Theses and Dissertations

There has been increasing interest in developing the ability for small unmanned aerial systems (SUAS) to be able to operate in environments where GPS is not available. This research considers the case of a larger aircraft loitering above a smaller GPS-denied SUAS. This larger aircraft is assumed to have greater resources which can overcome the GPS jamming and provide range information to the SUAS flying a mission below. This research demonstrates that using a ranging update combined with an aircraft motion model and visual odometry can greatly improve the accuracy of a SUASs estimated position in a GPS-denied environment.


Autoprov: An Automated File Provenance Collection Tool, Ryan A. Good Mar 2017

Autoprov: An Automated File Provenance Collection Tool, Ryan A. Good

Theses and Dissertations

A file's provenance is a detailing of its origins and activities. There are tools available that are useful in maintaining the provenance of a file. Unfortunately for digital forensics, these tools require prior installation on the computer of interest while provenance generating events happen. The presented tool addresses this by reconstructing a file's provenance from several temporal artifacts. It identifies relevant temporal and user correlations between these artifacts, and presents them to the user. A variety of predefined use cases and real world data are tested against to demonstrate that this software allows examiners to draw useful conclusions about the …


Perception Vs. Reality: Improving Mission Commander Decision-Making Capabilities By Use Of Heart Rate Zone Feedback In Training Environments, Caitlin M. Oviatt Mar 2017

Perception Vs. Reality: Improving Mission Commander Decision-Making Capabilities By Use Of Heart Rate Zone Feedback In Training Environments, Caitlin M. Oviatt

Theses and Dissertations

In the military environment, it is common for commanders to rely exclusively on perceptional information (e.g., visual observations) to make decisions on their personnel’s physical capabilities. There is little evidence to support the idea that the information provided by physiological feedback technology, typically made available to the individual visually, could improve assessments and decision-making capabilities of outside observers (e.g., mission commander in a remote location). Through experimental examination this research shows that commanders who have Heart Rate Zone (HRZ) biofeedback information about their Airmen by use of physiological technology were able to more accurately predict the level of effort and …


Using Multiple And Logistic Regression To Estimate The Median Will-Cost And Probability Of Cost And Schedule Overrun For Program Managers, Ryan C. Trudelle Mar 2017

Using Multiple And Logistic Regression To Estimate The Median Will-Cost And Probability Of Cost And Schedule Overrun For Program Managers, Ryan C. Trudelle

Theses and Dissertations

The main concern of a program manager is to manage the cost, schedule, and performance triad of a program. Historically, programs tend to meet the performance aspect at the expense of cost or schedule, or both. This research gives the acquisition community a set of tools that enables them to impartially analyze the cost and schedule of their programs, helping to mitigate these issues. Five regression models encompass this toolset; one to estimate the median program cost and four to identify the probability of realizing a given overrun. The cost model explains 81% of the variation in program acquisition using …


Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross Mar 2017

Total Electron Count Variability And Stratospheric Ozone Effects On Solar Backscatter And Lwir Emissions, John S. Ross

Theses and Dissertations

The development of an accurate ionospheric Total Electron Content (TEC) model is of critical importance to High Frequency (HF) radio wave propagation. However, the TEC is highly variable and is continuously influenced by geomagnetic storms, extreme Ultraviolet (UV) radiation, diurnal variation, and planetary waves. The ability to capture this variability is essential to improve current TEC models. Analysis of the growing body of data involving ionospheric fluctuations and thermal tides has revealed persistent correlation between increases in stratospheric ozone and variability of the TEC. The spectral properties of ozone show that it is a greenhouse gas that alters longwave emissions …


A Scenario-Based Parametric Analysis Of Stable Marriage Approaches To The Army Officer Assignment Problem, Matthew D. Ferguson Mar 2017

A Scenario-Based Parametric Analysis Of Stable Marriage Approaches To The Army Officer Assignment Problem, Matthew D. Ferguson

Theses and Dissertations

This paper compares linear programming and stable marriage approaches to the assignment problem under conditions of uncertainty. Robust solutions should exhibit reduced variability in the presence of one or more additional constraints. Several variations of each approach are compared with respect to solution quality, as measured by the overall social welfare among Officers and Assignments, and robustness as measured by the number of changes after a number of randomized perturbations. We examine the contrasts between these methods in the context of assigning Army Officers among a set of identified assignments. Additional constraints are modeled after realistic scenarios faced by Army …


Survival Analysis Of Us Air Force Officer Retention Rate, Courtney N. Franzen Mar 2017

Survival Analysis Of Us Air Force Officer Retention Rate, Courtney N. Franzen

Theses and Dissertations

Personnel retention is a matter of great interest in the private and public sectors. In the public sector--specifically the US Air Force--maintaining appropriate retention levels of rated officers is paramount as these officers are the backbone of the Air Force’s mission. As part of the effort to ensure proper retention rates for rated officers, retention models are created by the Air Force Personnel division that assist in predicting future retention patterns and accession needs. The techniques for creating these models, known as the "sustainment line," involve utilizing average retention percentages obtained from historical data. In this study, more statistical-based methods …


Using Markov Decision Processes With Heterogeneous Queueing Systems To Examine Military Medevac Dispatching Policies, Phillip R. Jenkins Mar 2017

Using Markov Decision Processes With Heterogeneous Queueing Systems To Examine Military Medevac Dispatching Policies, Phillip R. Jenkins

Theses and Dissertations

major focus of the Military Health System is to provide efficient and timely medical evacuation (MEDEVAC) to battlefield casualties. Medical planners are responsible for developing dispatching policies that dictate how aerial military MEDEVAC units are utilized during major combat operations. The objective of this research is to determine how to optimally dispatch MEDEVAC units in response to 9-line MEDEVAC requests to maximize MEDEVAC system performance. A discounted, infinite horizon Markov decision process (MDP) model is developed to examine the MEDEVAC dispatching problem. The MDP model allows the dispatching authority to accept, reject, or queue incoming requests based on the request's …