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Articles 1681 - 1710 of 5700
Full-Text Articles in Engineering
The Impact Of Reducing Full Time Support Positions In The U.S. Army National Guard And Reserves, Lucas J. Lease
The Impact Of Reducing Full Time Support Positions In The U.S. Army National Guard And Reserves, Lucas J. Lease
Theses and Dissertations
The United States Army is at a point in its history in which it, along with the other branches of the military, are experiencing cuts, constraints and a tightening of resources. The days of seemingly large budgets, abundant financial resources and high amounts of manpower are becoming a thing of the past. As the government reduces the allocations to the military, it is examining ways to reduce costs and improve its financial prospects. One of the positions examined for reduction or outright elimination is the full time support position in the U.S. Army National Guard (ARNG) and Reserves (USAR). The …
Long-Term Impacts Of Military Drawdown On The Industrial Base, Anton H. Martyn
Long-Term Impacts Of Military Drawdown On The Industrial Base, Anton H. Martyn
Theses and Dissertations
Since World War II, competition in the defense industry has fallen by over 90 percent. Over half of contracts currently executed by the United States Navy and Air Force are awarded without any competition. With the recent defense budget cuts, and an extended period of reduced defense spending ahead, more of which is going to sustainment and overhead than ever before, each year prime contractors are fighting over an even smaller piece of the procurement pie, which could have a deleterious effect on national security if these contractors go out of business or further consolidate through mergers. This study used …
Rate Setting Analysis: A Statistical Approach To Outlier Analysis In The Rate Setting Process Within The United States Transportation Command, Warren B. Mcgriff
Rate Setting Analysis: A Statistical Approach To Outlier Analysis In The Rate Setting Process Within The United States Transportation Command, Warren B. Mcgriff
Theses and Dissertations
The rate setting process implemented by the USTRANSCOM J8 Program Analysis & Financial Management Directorate (USTC J8 or TCJ8) is of importance, as accurate rates yield proper and equitable recoupment of costs from customers and ensure USTC can achieve an accurate Net Operating Result (NOR) in each given year. This research sought to identify areas in which the current rate setting methodology can be improved. We initially examined the use of six months of historical cost data versus a full year of data to set rates, concluding that there is not a statistically significant difference with respect to their relative …
Modeling The Components Of An Economy As A Complex Adaptive System, Richard J. Mickelsen
Modeling The Components Of An Economy As A Complex Adaptive System, Richard J. Mickelsen
Theses and Dissertations
Complex systems science is a relatively new discipline and has not been widely applied to the field of economics. Much of current economic theory relies on principles of constrained optimization and often fails to see economic variables as part of an interconnected network. While tools for forecasting economic indicators are based primarily on autoregressive techniques, these techniques are not always well-suited to predicting the future performance of highly volatile data sets such as the stock market. This research portrays the stock market as one component of a networked system of economic variables, with the federal funds rate acting as an …
Modeling And Economy’S Dynamics And External Influences Through A System Of Differential Equations, Thomas M. Dickey
Modeling And Economy’S Dynamics And External Influences Through A System Of Differential Equations, Thomas M. Dickey
Theses and Dissertations
This research proposes a methodology to develop models for the greater understanding of the application of the economic instrument of national power through a selection of factors that define the economic condition of a country. The major components of an economy are identified as GDP per capita, a treasury bond yield, and a major stock market index. The components have interconnected dynamics along with external influences from the United Stated Federal Funds Rate and foreign direct investment. These connections are considered through a metamodel in the form of a system of differential equations which is solved as an inverse problem. …
A Logistic Regression And Markov Chain Model For The Prediction Of Nation-State Violent Conflicts And Transitions, Nicholas Shallcross
A Logistic Regression And Markov Chain Model For The Prediction Of Nation-State Violent Conflicts And Transitions, Nicholas Shallcross
Theses and Dissertations
Using open source data, this research formulates and constructs a suite of statistical models that predict future transitions into and out of violent conflict and forecasts the regional and global incidences of violent conflict over a ten-year time horizon. A total of thirty predictor variables are tested and evaluated for inclusion in twelve conditional logistic regression models, which calculate the probability that a nation will transition from its current conflict state, either In Conflict or Not in Conflict, to a new state in the following year. These probabilities are then used to construct a series of nation-specific Markov chain models …
Optimizing Forecasting Methods For Ustranscom Railcar Demands, James M. Park
Optimizing Forecasting Methods For Ustranscom Railcar Demands, James M. Park
Theses and Dissertations
The United States military heavily relies on rail freight operations to meet many of its logistical needs during both peacetime and wartime efforts. As the head organization responsible for managing and overseeing all modes of military transportation, United States Transportation Command depends on timely accurate railcar demand forecasts to drive critical decisions on distribution and placement of railcar assets. However, the intermittent nature of railcar demands based on location and commodity make it a challenging task for forecasters. Furthermore, these “lumpy” demands often come without any obvious trends or seasonality. This study explores the utility of both traditional forecasting methods …
Sortie Generation Simulation Of A Fighter Squadron, Abdurrahman Sevimli
Sortie Generation Simulation Of A Fighter Squadron, Abdurrahman Sevimli
Theses and Dissertations
The Turkish Air Force utilizes several fighter squadrons to enhance its military capabilities. One of the most critical challenges for these squadrons is generating sorties to meet the currency and demand during both peacetime and wartime. This sortie generation process directly affects the success of both training and operations. In this study, this process is assessed using a discrete event simulation. Air Force decision makers require a simulation tool to conduct “what-if” analysis on how potential changes in the environment affect an F-16 fighter squadron’s sortie generation process. Creating a usable simulation provides decision makers with a flexible tool to …
Methods To Address Extreme Class Imbalance In Machine Learning Based Network Intrusion Detection Systems, Russell W. Walter
Methods To Address Extreme Class Imbalance In Machine Learning Based Network Intrusion Detection Systems, Russell W. Walter
Theses and Dissertations
Despite the considerable academic interest in using machine learning methods to detect cyber attacks and malicious network traffic, there is little evidence that modern organizations employ such systems. Due to the targeted nature of attacks and cybercriminals’ constantly changing behavior, valid observations of attack traffic suitable for training a classifier are extremely rare. Rare positive cases combined with the fact that the overwhelming majority of network traffic is benign create an extreme class imbalance problem. Using publically available datasets, this research examines the class imbalance problem by using small samples of the attack observations to create multiple training sets that …
Increased Capacity Utilizing Aggregation And Consolidation Of Contingency Cargo, Cassidy L. Wilson
Increased Capacity Utilizing Aggregation And Consolidation Of Contingency Cargo, Cassidy L. Wilson
Theses and Dissertations
Maximizing use of limited airlift assets is a common problem during large contingency operations. Requirements often exceed airlift capacity and fiscal constraints driving the need to aggregate conveyance loads both within and across business lines (Unit Line Number (ULN), Special Assignment Airlift Mission (SAAM), and sustainment). Current methods of consolidation are completed by planners at the 618th Air Operations Center. This process is completed by piecing email correspondence and making individual localized decisions which are not always consistent with big picture efficiency. United States Transportation Command requested a study to create standard business rules or a methodology that can benefit …
Application Of Non-Rated Line Officer Attrition Levels And Career Field Stability, Christine L. Zens
Application Of Non-Rated Line Officer Attrition Levels And Career Field Stability, Christine L. Zens
Theses and Dissertations
The Air Force monitors the strength of its active duty officer force and attempts to achieve the difficult challenge of employing a diversity of talent among career specialties and experience levels. This study completes two objectives, predicting future manning levels for 23 career fields, and providing a statistical framework to assess the stability of these fields. The first part of the study applies regression and survival analysis to subpopulations within the active duty Air Force officer corps, and then aggregates them by year to forecast future personnel levels. Four career fields are considered, including Acquisitions (ACQ), Logistics (LOG), Support (SPT), …
Analysis Of Neutron Effects For Asteroid Disruption, Aaron J. Ferguson
Analysis Of Neutron Effects For Asteroid Disruption, Aaron J. Ferguson
Theses and Dissertations
The use of nuclear weapons is one possible method for disrupting or deflecting an asteroid on a trajectory to impact the earth. A largely unexplored component of weapon yield in a disruption scenario is the impact of the neutron output. The results of MCNP-6 simulations are presented demonstrating the effect that incident neutron energy has on the total energy deposited in an asteroid, including that the efficiency of energy deposition in a material is inversely proportional to the incident neutron energy due to negative Q-value reactions. The effects of material composition on the total energy deposited as well as the …
Evaluation Of The Visible Infrared Imaging Radiometer Suite (Viirs) Cloud Base Height (Cbh) Pixel-Level Retrieval Algorithm For Single-Layer Water Clouds, Kyle E. Fitch
Theses and Dissertations
Evaluation of the Visible Infrared Imaging Radiometer Suite (VIIRS) Cloud Base Height (CBH) product was accomplished. CBH is an important factor for aviation, but a lack of coverage for ground-based retrieval is a significant limitation. Space-based retrieval is essential; therefore, the VIIRS CBH pixel-level retrieval algorithm was assessed for single-layer water clouds. Accurate (truth) measurements were needed not only for the CBH product, but also for VIIRS cloud optical thickness (COT), effective particle size (EPS), and cloud top height (CTH). Data from Atmospheric Radiation Measurement (ARM) sites were used, with VIIRS-ARM matchups created from June 2013 through October 2015 for …
Radiation Effects In Thin Film Hexagonal Boron Nitride, Nathaniel M. Kaminski
Radiation Effects In Thin Film Hexagonal Boron Nitride, Nathaniel M. Kaminski
Theses and Dissertations
The radiation response of 2 nm and 12 nm hexagonal boron nitride (hBN) thin film insulators was studied using metal insulator semiconductor (MIS) devices. Current-voltage, capacitance-voltage, and impedance spectroscopy measurements were compared to quantify changes in hBN resistance due to radiation damage. MIS devices exposed to a gamma total dose deposition of 3.1 Mrad(Si) from a Co- 60 source exhibited a small increase in hBN resistance and no observable C-V shift associated with charge trapping. MIS devices irradiated with 4.5 MeV silicon ions showed no significant resistivity decrease to a threshold fluence of 1 ×1012 for the 2 nm …
Optically Stimulated Luminescence From Ag-Doped Lithium Tetraborate (Li2b4o7), Ember S. Maniego
Optically Stimulated Luminescence From Ag-Doped Lithium Tetraborate (Li2b4o7), Ember S. Maniego
Theses and Dissertations
Silver-doped lithium tetraborate (Li2B4O7) crystals emit optically stimulated luminescence (OSL) in response to stimulating light around 400 nm. Photoluminescence, optical absorption, and electron paramagnetic resonance (EPR) were used to identify the defects in the crystal that cause this OSL. Lithium tetraborate crystals have Ag+ ions at Li+ sites and at interstitial sites. Upon ionization at room temperature via x rays, electron-hole pairs are generated. The electrons are trapped at Ag+ occupying interstitial sites, while the holes are trapped at Ag+ at lithium sites. The trapped electron centers become Ag0 …
Automated Sunspot Classification And Tracking Using Sdo/Hmi Imagery, Maclane A. Townsend
Automated Sunspot Classification And Tracking Using Sdo/Hmi Imagery, Maclane A. Townsend
Theses and Dissertations
Verification of an automated sunspot detection and classification algorithm is conducted utilizing two years of solar imagery from NASA's Solar Dynamics Observatory (SDO) satellite. Automated McIntosh classifications are compared against sunspot reports from the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Center (SWPC) using a three-tiered comparison metric. Statistical confidence is demonstrated for algorithm performance and consistency when compared against the SWPC data set, suggesting future applications of the algorithm will perform similarly. A sunspot tracking algorithm is added to the existing code and demonstrates reliable feature tracking for time periods out to four days between consecutive images. …
Evaluation Of Verification Approaches Applied To A Nonlinear Control System, Kerianne H. Gross
Evaluation Of Verification Approaches Applied To A Nonlinear Control System, Kerianne H. Gross
Theses and Dissertations
As the demand for increasingly complex and autonomous systems grows, designers may consider computational and artificial intelligence methods for more advanced, re- active control. While the performance gained by such increasingly intelligent systems may be superior to traditional control techniques, the lack of transparency in the systems and opportunity for emergent behavior limits their application in the field. New verification and validation methods must be developed to ensure the output of such controllers do not put the system or any people interacting with it in danger. This challenge was highlighted by the former Air Force Chief Scientist in his 2010 …
Civil Engineer Company Grade Officer Training Needs Analysis For Contingency Operations, Brian S. Greszler
Civil Engineer Company Grade Officer Training Needs Analysis For Contingency Operations, Brian S. Greszler
Theses and Dissertations
In terms of active duty personnel, the USAF is the smallest it has ever been since its creation in 1947. With fewer personnel to accomplish essential tasks, the training of Airmen is more important than ever. Outdated and irrelevant training can lead to gaps in the knowledge of trainees. The purpose of this research was to analyze the training needs of Civil Engineer (CE) Company Grade Officers (CGOs) in the contingency environment. This was done by first conducting a Job Analysis (JA). The JA resulted in a list of 36 critical tasks and 58 important Knowledge, Skills, and Abilities (KSAs). …
Enhancing Virtual Team Dynamics, Freddie L. Stephens Ii
Enhancing Virtual Team Dynamics, Freddie L. Stephens Ii
Theses and Dissertations
With the activation of the Air Force Civil Engineer Center in 2012, the United States Air Force initiated an effort to centralize installation and mission support management throughout the Air Force, while decentralizing the execution at the base level. The measurement of success for such a decision extends beyond the reduction of overhead costs. The goal was to build a responsive, mission-focused organization. This research evaluated specific factors associated with the characteristics of virtual team dynamics to improve the perceived responsiveness of a centralized organization. Leader-member exchange (LMX) theory is a relationship-based approach to leadership that focuses on the quality …
Application Of System Engineering Leading Indicators To Scrum Agile Projects, Eric M. Shirley
Application Of System Engineering Leading Indicators To Scrum Agile Projects, Eric M. Shirley
Theses and Dissertations
SCRUM Agile metrics and System Engineering Leading Indicators (SE LIs) are measures used to evaluate the effectiveness and performance of a project across its lifecycle. The application of metrics can provide information on both internal resources and external project stakeholder requirements and constraints, showing past changes, trends, and potential future impacts. Both SCRUM Agile and SE LIs are designed to give a systems engineer/project manager insight into development progress allowing for progress to be checked at regular intervals as well as early corrective actions to be taken if necessary. This research applied SE LIs to a SCRUM Agile project to …
Mission Dependency Index Of Air Force Built Infrastructure: Knowledge Discovery With Machine Learning, Clark W. Smith
Mission Dependency Index Of Air Force Built Infrastructure: Knowledge Discovery With Machine Learning, Clark W. Smith
Theses and Dissertations
Mission Dependency Index (MDI) is a metric developed to capture the relative criticality of infrastructure assets with respect to organizational missions. The USAF adapted the MDI metric from the United States Navy’s MDI methodology. Unlike the Navy’s MDI data collection process, the USAF adaptation of the MDI metric employs generic facility category codes (CATCODEs) to assign MDI values. This practice introduces uncertainty into the MDI assignment process with respect to specific missions and specific infrastructure assets. The uncertainty associated with USAF MDI values necessitated the MDI adjudication process. The MDI adjudication process provides a mechanism for installation civil engineer personnel …
Optimizing Allocation Of U.S. Humanitarian Civic Assistance Projects In Support Of Developing Foreign Democracy, Christopher E. Wittman
Optimizing Allocation Of U.S. Humanitarian Civic Assistance Projects In Support Of Developing Foreign Democracy, Christopher E. Wittman
Theses and Dissertations
Humanitarian projects in foreign countries are funded by the U.S. government to foster peace, prosperity, and the spread of democratic ideals around the globe. The type and scope of projects are restricted by current doctrine and funding regulations. Specifically in 2014, USAF personnel supported medical and educational construction projects/programs in the country of Belize. Within Belize, medical and educational projects were funded under the Humanitarian and Civic Assistance (HCA) program through the NEW HORIZONS exercise. Fiscal constraints, including shrinking budgets due to sequestration, have placed greater emphasis in the responsible distribution of resources and foreign assistance. The purpose of this …
The Effect Of Ph And Pulsed Ultraviolet Light Emitting Diode Duty Cycles On The First Order Rate Constant And Byproduct Profile Of The Advanced Oxidation Of Tartrazine, Brandon M. Stewart
The Effect Of Ph And Pulsed Ultraviolet Light Emitting Diode Duty Cycles On The First Order Rate Constant And Byproduct Profile Of The Advanced Oxidation Of Tartrazine, Brandon M. Stewart
Theses and Dissertations
Water treatment capability is required for military operations, production of drinking water, and industrial wastewater treatment. The Advanced Oxidation Process (AOP) is one of many viable steps for treating water; however, it is important to understand the byproducts of the treatment process to avoid creating other constituents more severe than the first. Tartrazine (TAR) was oxidized with pulsed Ultra- Violet (UV) Light Emitting Diodes (LEDs) in combination with hydrogen peroxide (H2O2) in an AOP at the laboratory scale. The relative concentration of TAR was reduced from 1 to between 1 – 0.75 over pH values between 6 and 9, and …
Formation Flight Of Earth Satellites On Low-Eccentricity Kam Tori, Christopher T. Craft
Formation Flight Of Earth Satellites On Low-Eccentricity Kam Tori, Christopher T. Craft
Theses and Dissertations
The problem of Earth satellite constellation and formation flight is investigated in the context of Kolmogorov-Arnold-Moser (KAM) theory. KAM tori are constructed utilizing Wiesel’s Low-Eccentricity Earth Satellite Theory, allowing numerical representation of the perturbed tori describing Earth orbits acted upon by geopotential perturbations as sets of Fourier series. A maneuvering strategy using the local linearization of the KAM tangent space is developed and applied, demonstrating the ability to maneuver onto and within desired torus surfaces. Constellation and formation design and maintenance on KAM tori are discussed, along with stability and maneuver error concerns. It is shown that placement of satellites …
Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham
Localized Plasma Measurement During Instability Modes In A Hall Thruster, David A. Cunningham
Theses and Dissertations
Hall thrusters are a key technology for current and future unmanned satellites, striking a balance between thrust and fuel economy suitable for many mission profiles of interest. Despite their extensive flight heritage and a large body of research, many phenomena occurring in the plasma discharge of Hall thrusters are not well understood. A combination of intrusive and non-intrusive measurement techniques were used to investigate the properties of the exhaust plume of two Hall thrusters and correlate optical characteristics of oscillating modes with the plasma potential and azimuthal current distribution during those modes. A strong trend was found associating the optical …
Key Detection Rate Modeling And Analysis For Satellite-Based Quantum Key Distribution, Jonathan C. Denton
Key Detection Rate Modeling And Analysis For Satellite-Based Quantum Key Distribution, Jonathan C. Denton
Theses and Dissertations
A satellite QKD model was developed and validated, that allows a user to determine the optimum wavelength for use in a satellite-based QKD link considering the location of ground sites, selected orbit and hardware performance. This thesis explains how the model was developed, validated and presents results from a simulated year-long study of satellite-based quantum key distribution. It was found that diffractive losses and atmospheric losses define a fundamental trade space that drives both orbit and wavelength selection. The optimal orbit is one which generates the highest detection rates while providing equal pass elevation angles and durations to multiple ground …
Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks
Surface Roughness Of Electron Beam Melting Ti-6al-4v Effect On Ultrasonic Testing, Evan T. Hanks
Theses and Dissertations
Experimental research was conducted on the effects of surface roughness on ultrasonic non-destructive testing of Electron Beam Melted (EBM) additively manufactured Ti-6Al-4V. Additive Manufacturing (AM) is a developing technology with many potential benefits, but certain challenges posed by its use require further research before AM parts are viable for widespread use in the aviation industry. Possible applications of this new technology include, Aircraft Battle Damage Repair (ABDR), small batch manufacturing to fill supply gaps, and replacement for obsolete parts. The research presented here assesses the effectiveness of ultrasonic inspection in detecting manufactured flaws in EBM manufactured Ti-6Al-4V. EBM products are …
Enhanced Flow Migration In Full Annular Ultra Compact Combustor, Nicholas A. Gilbert
Enhanced Flow Migration In Full Annular Ultra Compact Combustor, Nicholas A. Gilbert
Theses and Dissertations
Since combustion efficiency in modern jet engines has stabilized, attention has turned to improving the combustor by improving the thrust-to-weight ratio. The Ultra Compact Combustor (UCC) is a means to reduce the weight of the combustor while ensuring exhaust meets increasingly stringent government emission standards. Combustion occurs within the UCC under a g-load in the circumferential direction, which maintains combustion efficiency while decreasing axial combustor length. Previous analysis optimized the combustion chamber flame characteristics with a common upstream air source. Previously, issues for the UCC were inspired by integration into a traditional axial turbojet. The focus of this investigation was …
Space Object Self-Tracker On-Board Orbit Determination Analysis, Stacie M. Flamos
Space Object Self-Tracker On-Board Orbit Determination Analysis, Stacie M. Flamos
Theses and Dissertations
Due to the United States' growing dependence on space based assets and the in- creasing number of resident space objects (RSO), improvement of Space Situational Awareness (SSA) capabilities is more necessary than ever. As a way to aid in this need, the Air Force Institute of Technology (AFIT) is developing the Space Object Self-Tracker (SOS) as a proof-of-concept experimental satellite for RSO precision tracking and collision avoidance system in Low Earth Orbit (LEO). Specifically, SOS will use Global Positioning System (GPS) position estimates for on-board orbit de- termination. Currently, SOS will use the Simplified General Perturbations-4 (SGP4) algorithm as its …
Evaluation Of Unmanned Aircraft Flying Qualities Using Jsbsim, Joshua P. Kim
Evaluation Of Unmanned Aircraft Flying Qualities Using Jsbsim, Joshua P. Kim
Theses and Dissertations
Flying qualities data can be used to predict the future performance of aircraft; however, no flying qualities requirements exist for Unmanned Aerial Vehicles (UAVs). The intent of flying qualities requirements is to guarantee the safety and operational effectiveness of the aircraft. Flying qualities requirements have been extensively researched and specified for fixed-wing and rotary-wing manned aircraft based on a substantial database of assessments. The critical issue today in flying qualities is how to extend them to pilotless aircraft. A simulation study using an open-source flight dynamics model (JSBSim) was conducted to perform various performance maneuvers and evaluate how well the …