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Articles 361 - 390 of 1284

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Application Of Classification In Machine Learning: An Analysis Of Highway-Rail Grade Crossing Systems Safety, Christopher John Helmer Cox Aug 2020

Application Of Classification In Machine Learning: An Analysis Of Highway-Rail Grade Crossing Systems Safety, Christopher John Helmer Cox

Theses and Dissertations

Highway-rail grade crossing accidents are the second leading cause of fatalities within the railway transportation industry. Highway-rail grade crossing fatality statistics have failed to improve over the last decade, and in some years have increased. Because of these trends, research has found that considerable Federal funding initiatives exist to support and develop contemporary risk reduction methodologies involving machine learning and artificial intelligence. In accord with these initiatives, this thesis investigates the highway-rail grade crossing safety problem using machine learning to implement an ensemble decision tree-based classification application. The resulting classifier has been validated to achieve a less than three percent …

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Viability Of Augmented Reality For Machine Maintenance, Wesley Robert Ferguson Jul 2020

Viability Of Augmented Reality For Machine Maintenance, Wesley Robert Ferguson

Theses and Dissertations

Augmented reality has come a long way in the past decades in the manner of reduced costs and increased reliability. Despite these developments, there is still a difficulty bridging the gap between practical use and pure theory. This work explores if the current state of augmented reality is at a stage that can be utilized to implement solutions for heavy machinery maintenance routines by exploring the quality of education from augmented reality applications, capturing said maintenance routines for our own system, then replicating them in an augmented reality application with consumer grade equipment.

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How Predictable Is Space Exploration?, Michael Christopher Howell May 2020

How Predictable Is Space Exploration?, Michael Christopher Howell

Theses and Dissertations

Recent research has suggested that progress in technological domains often improves in an exponential manner. The traditional method to model this increase in capability has been to fit a model with time or effort as an independent variable and then extrapolate the trend (Moore, 1965, Wright, 1936, Magee et al., 2014). Although other methods have been used as well (Nagy et al, 2013). While effective, these methods are not the only way to forecast such trends and they have their own limitations. Recent research has indicated that a potentially useful approach for modeling technological improvement is time series analysis. I …

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Lightning Prediction For Space Launch Using Machine Learning Based Off Of Electric Field Mills And Lightning Detection And Ranging Data, Anson Cheng Mar 2020

Lightning Prediction For Space Launch Using Machine Learning Based Off Of Electric Field Mills And Lightning Detection And Ranging Data, Anson Cheng

Theses and Dissertations

Kennedy Space Center and Cape Canaveral Air Station, FL, where the Air Force conducts space launches, are in an area of frequent lightning strikes, which is main obstacle in meeting launch goals. The 45th Weather Squadron (45th WS) ensures that any weather safety requirements are met during pre-launch and actual space launch. Using only summer months from three years’ worth of lightning detection and ranging (LDAR) and electric field mill (EFM) data from KSC, several feedforward neural networks are constructed. Separate models are built for each EFM and trained by adjusting parameters to forecast lightning 30 minutes out in the …

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A Metamodel Recommendation System Using Meta-Learning, Megan K. Woods Mar 2020

A Metamodel Recommendation System Using Meta-Learning, Megan K. Woods

Theses and Dissertations

The importance and value of statistical predictions increase as data grows in availability and quantity. Metamodels, or surrogate models, provide the ability to rapidly approximate and predict information. However, selection of the appropriate metamodel for a given dataset is often arduous, and the choice of the wrong metamodel could lead to considerably inaccurate results. This research proposes and tests the framework for a metamodel recommendation system. The implementation allows for virtually any dataset and preprocesses data, calculates meta-features, evaluates the performance of various metamodels, and learns how the data behaves via meta-learning, thus preparing and bettering itself for future recommendations. …

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Database Analysis To Improve U.S. Transportation Command Forecasting Processes, Maxwell C. Thompson Mar 2020

Database Analysis To Improve U.S. Transportation Command Forecasting Processes, Maxwell C. Thompson

Theses and Dissertations

The United States Transportation Command (USTRANSCOM) facilitates air, land, and sea transportation for the DOD. On a periodic basis, a myriad of different agencies within USTRANSCOM project future workload to facilitate resource planning, budgeting, and reimbursable rate identification. Within USTRANSCOM, there are a variety of databases and metrics utilized for workload forecasts; neither a standard nor a preferred technique is prescribed. Currently, USTRANSCOM faces challenges in producing accurate workload forecasts [1]. These challenges can lead to unreliable budget requests and, ultimately, hinder the effectiveness and efficiency of USTRANSCOM [1]. For the purpose of routine aircraft movements of cargo and personnel, …

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Ground Weather Radar Signal Characterization Through Application Of Convolutional Neural Networks, Stephen M. Lee Mar 2020

Ground Weather Radar Signal Characterization Through Application Of Convolutional Neural Networks, Stephen M. Lee

Theses and Dissertations

The 45th Weather Squadron supports the space launch efforts out of the Kennedy Space Center and Cape Canaveral Air Force Station for the Department of Defense, NASA, and commercial customers through weather assessments. Their assessment of the Lightning Launch Commit Criteria (LLCC) for avoidance of natural and rocket triggered lightning to launch vehicles is critical in approving space shuttle and rocket launches. The LLCC includes standards for cloud formations, which requires proper cloud identification and characterization methods. Accurate reflectivity measurements for ground weather radar are important to meet the LLCC for rocket triggered lightning. Current linear interpolation methods for ground …

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Mc80: Quantifying Effect Of Fleet Health On Sortie Execution In F-16 Fleet, Kyle R. Gladney Mar 2020

Mc80: Quantifying Effect Of Fleet Health On Sortie Execution In F-16 Fleet, Kyle R. Gladney

Theses and Dissertations

By order of the Secretary of Defense, all of the US Air Force's F-16 units were tasked to improve their fleet health to a Mission Capability (MC) rate of 80 percent, as part of a Department of Defense-wide push to make its Critical Aviation Platforms, and the units that employ them, more ready and lethal. This study uses historical fleet health and sortie execution data captured from LIMS-EV (Weapon System Viewer, 2020) to create a multiple regression model that quantifies the value of increased fleet health, defined as either MC rate or Aircraft Availability (AA) rate, in terms of increasing …

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Multivariate Analysis Of Human Performance Strong Lab Data, Kayla N. Tinucci Mar 2020

Multivariate Analysis Of Human Performance Strong Lab Data, Kayla N. Tinucci

Theses and Dissertations

This study uses multivariate analysis methods to find relationships between nutrition and wellness and nutrition and performance. The nutrition, daily wellness, and weight and bodyfat data are from a study performed by the STRONG lab in the 711th Human Performance Wing. Electronically collected nutrition data along with survey data for 19 individuals over a 12-week study period are examined with a focus on health, fitness, and nutrition. Factor analysis and linear regression are performed and inferences are drawn regarding what effects calories and macronutrient intake have on subjects perceived wellness, weight, and body fat percentage. These insights are discussed in …

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Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram Mar 2020

Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram

Theses and Dissertations

This research focused on understanding the phenomena behind the cost growth of Weapon System Sustainment (WSS) and the simultaneous degradation in USAF aircraft system availability. The primary modelling technique used was Ordinary Least Squares (OLS) while incorporating temporal effect. Other studies have looked at cost factors related to the Flying Hour Program, flying conditions and age. This study found empirical relationships between each of the four WSS business processes and the lead time in months it takes to realize improvements in system aircraft availability.

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Providing Rational For Further Funding Additive Manufacturing Efforts In The Air Force, Trever J. Braunberger Mar 2020

Providing Rational For Further Funding Additive Manufacturing Efforts In The Air Force, Trever J. Braunberger

Theses and Dissertations

Extremely long lead times for legacy aircraft replacement parts often exceed 120 days and cost 3 to 4 times the original price drives a search for alternative manufacturing methods such as additive manufacturing. Currently, the method to procuring a legacy replacement for aircraft such as the C-130 is daunting and at times, impossible. Through a comprehensive knowledge collection of organizational data the Air Force body of knowledge increases and provides actionable data to decision makers which has the potential of dramatically decreasing part wait times and procurement. The proposed, intuitive decision analysis framework mapped out in this research provides relevant …

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Preliminary Study Of Communication Network Characterization Towards Improved Organizational Behavior, Taylor F. Flaxington Mar 2020

Preliminary Study Of Communication Network Characterization Towards Improved Organizational Behavior, Taylor F. Flaxington

Theses and Dissertations

Nearly one third of the Air Force acquisition system’s large programs are over cost and half are over budget; performance must improve. This research applies a systems perspective to this challenge and frames the acquisition system as a complex system of systems. It is a system composed of people in multiple organizations; organizations interacting with one another to develop, acquire and sustain weapon programs. The system’s performance is an emergent behavior of its components (people), structure and processes. Communication networks are a view of a system’s structure, revealing the flows and interactions between components (people) as the system accomplishes its …

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Golng Off The Grid: Optimizing Solar Renewable Energy Systems At Remote Locations To Minimize Logistics Requirements, Increase Sustainability, And Strengthen Energy Assurance, Nathanael J. Thomsen Mar 2020

Golng Off The Grid: Optimizing Solar Renewable Energy Systems At Remote Locations To Minimize Logistics Requirements, Increase Sustainability, And Strengthen Energy Assurance, Nathanael J. Thomsen

Theses and Dissertations

Grid-based electrical infrastructure is unavailable at many remote locations including developing nation communities, isolated construction sites, and military contingency bases. Powering these locations with diesel generators requires regular fuel resupply, resulting in increased costs, environmental impacts, and burdensome logistics—making generators an obstacle for energy resiliency and sustainability. This research examines using solar renewable energy systems to replace generators at remote locations and presents a multi-objective optimization model that minimizes logistics variables. Replacing a single deployed generator would save over 500,000 gal of fuel annually, eliminating the need for 100 fuel tanker deliveries.

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A Comparison Of Sbir Investment Methods: Afwerx Vs Legacy, Evan A. Gist Mar 2020

A Comparison Of Sbir Investment Methods: Afwerx Vs Legacy, Evan A. Gist

Theses and Dissertations

The AFWERX Open Topic (AOT) program uses funding from the United States Air Force’s (USAF) Small Business Innovation and Research (SBIR) budget to adapt commercial technology to USAF needs. The AOT approach to small business investment is markedly different from that of legacy SBIR investment methods. This research is a comparison of processes and outcomes for AOT and legacy SBIR. The first axis of comparison is on commercialization rates. Applying a legacy definition of commercialization on a sample of AOT contracts, we found AOT’s commercialization to be 37% (compared to an 8.8% for legacy SBIR). We caveat this finding by …

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Investigating Lifecycle Costs Of Optimized Battery-Photovoltaic Systems On A Forward Operating Base, Neal S. Fennell Mar 2020

Investigating Lifecycle Costs Of Optimized Battery-Photovoltaic Systems On A Forward Operating Base, Neal S. Fennell

Theses and Dissertations

The purpose of this research was to investigate the total life-cycle cost of using utility-scale battery systems to increase the energy efficiency of forward operating bases, thereby reducing the burden of diesel fuel logistics. Specifically, this thesis answered three research questions addressing optimal sizing for various battery types connected with photovoltaic grids, logistical parameters directly impacting total cost, and the cost of increasing the energy resilience of the network. The research questions were answered through a review of literature, modeling, and data analysis. The model determines an optimal size and area for a Vanadium redox flow, Lithium-ion, or Lead-acid battery …

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Defense Contractor Profit, Clayton S. Eilert Mar 2020

Defense Contractor Profit, Clayton S. Eilert

Theses and Dissertations

This research seeks to achieve two objectives: 1) to provide a comprehensive survey of research related to defense contractor profitability, and 2) to conduct an updated analysis of such profitability. No previous comprehensive survey of the topic was found in the academic literature. Therefore, the provision of such a survey may significantly benefit future researchers. A paucity of recent defense contractor profit research related was identified; only one published study analyzed data after 2000 and none used data more recent than 2010. This research reconciles the gap in recent defense contractor profit studies via objective two. Panel data analysis is …

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Predicting Upper Atmospheric Weather Conditions Utilizing Long-Short Term Memory Neural Networks For Aircraft Fuel Efficiency, Garrett A. Alarcon Mar 2020

Predicting Upper Atmospheric Weather Conditions Utilizing Long-Short Term Memory Neural Networks For Aircraft Fuel Efficiency, Garrett A. Alarcon

Theses and Dissertations

Aviation fuel is a major component of the Air Force (AF) budget, and vital for the core mission of the AF. This study investigated the viability of LSTMs to increase the accuracy of deterministic NWP models, while also investigating the ability to reduce model generation time. Increased forecast accuracy for wind speeds could be implemented into existing flight path models to further increase fuel efficiency, while reduced modeling times would allow flight planners to generate a flight plan in rapid response situations. The most viable model consisted of an ensemble of six LSTMs trained o six coordinates. The model's error …

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Algorithm Selection Framework: A Holistic Approach To The Algorithm Selection Problem, Marc W. Chalé Mar 2020

Algorithm Selection Framework: A Holistic Approach To The Algorithm Selection Problem, Marc W. Chalé

Theses and Dissertations

A holistic approach to the algorithm selection problem is presented. The “algorithm selection framework" uses a combination of user input and meta-data to streamline the algorithm selection for any data analysis task. The framework removes the conjecture of the common trial and error strategy and generates a preference ranked list of recommended analysis techniques. The framework is performed on nine analysis problems. Each of the recommended analysis techniques are implemented on the corresponding data sets. Algorithm performance is assessed using the primary metric of recall and the secondary metric of run time. In six of the problems, the recall of …

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Analysis And Forecasting Of The 360th Air Force Recruiting Group Goal Distribution, Tyler Spangler Mar 2020

Analysis And Forecasting Of The 360th Air Force Recruiting Group Goal Distribution, Tyler Spangler

Theses and Dissertations

This research utilizes monthly data from 2012-2017 to determine economic or demographic factors that significantly contribute to increased goaling and production potential in areas of the 360th Recruiting Groups. Using regression analysis, a model of recruiting goals and production is built to identify squadrons within the 360 RCGs zone that are capable of producing more or fewer recruits and the factors that contribute to this increased or decreased capability. This research identifies that a zones high school graduation rate, the number of recruiters, and the number of JROTC detachments in a zone are positively correlated with recruiting goals and that …

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Human Performance Modeling: Analysis Of The Effects Of Manned-Unmanned Teaming On Pilot Workload And Mission Performance, Jinan M. Andrews Mar 2020

Human Performance Modeling: Analysis Of The Effects Of Manned-Unmanned Teaming On Pilot Workload And Mission Performance, Jinan M. Andrews

Theses and Dissertations

Due to the advent of autonomous technology coupled with the extreme expense of manned aircraft, the Department of Defense (DoD) has increased interest in developing affordable, expendable Unmanned Aerial Vehicles (UAVs) to become autonomous wingmen for jet fighters in mosaic warfare. Like a mosaic that forms a whole picture out of smaller pieces, battlefield commanders can utilize disaggregated capabilities, such as Manned-Unmanned Teaming (MUM-T), to operate in contested environments. With a single pilot controlling both the UAVs and manned aircraft, it may be challenging for pilots to manage all systems should the system design not be conducive to a steady …

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Trade-Space Analysis Of A Small Unmanned Vehicle System For Radiological Search Missions, Sam B. Harriger Mar 2020

Trade-Space Analysis Of A Small Unmanned Vehicle System For Radiological Search Missions, Sam B. Harriger

Theses and Dissertations

Nuclear and radiological terrorism is a persistent threat to United States national security. The research and development of new technological capabilities is vital to bolstering emergency response and prevention capabilities in support of national security initiatives. This research characterized the applicable trade-space for a system of unmanned vehicles deployed for search, detection, and identification of radiological source material. Exploration included the development of a CONOPS, a functional decomposition and physical allocation, design considerations, and an analysis of feasibility and utility. The concept system comprises of a ground control station, ground vehicle, hybrid-electric multirotor, and fixed-wing vehicle with an open architecture …

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Preferred Treatment Methods For Patients With Inflammatory Bowel Disease, James L. Deitschel Mar 2020

Preferred Treatment Methods For Patients With Inflammatory Bowel Disease, James L. Deitschel

Theses and Dissertations

Shared decision making is the concept of physicians involving patients in the treatment planning process. The University of Maryland Medical Center is interested in applying shared decision making to the treatment of patients with Inflammatory Bowel Disease (IBD). The two treatment methods analyzed in this study were medical management and surgery. To explore patient preferences between these two alternatives, a discrete choice experiment (DCE) was employed. The responses for the DCE were binary, so logistic regression models were explored. The conditional logistic regression model was determined to be the most appropriate for this analysis. After step-wise regression was performed, a …

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Analysis With Dynamic Bayesian Networks Compared To Simulation, Aaron J. Salazar Mar 2020

Analysis With Dynamic Bayesian Networks Compared To Simulation, Aaron J. Salazar

Theses and Dissertations

This research compares simulations to Dynamic Bayesian Networks in analyzing situations. The research applies models that have known output mean and variance. Queueing systems have theoretical values of the steady-state mean and variance for the number of entities in the system. Monte Carlo simulation development is broken down into two separate approaches: discrete-event simulation and time-oriented simulation. The discrete-event simulation uses pseudo-random numbers to schedule and trigger future events (i.e. customer arrivals and services) and is based on the generated objects.The time-oriented simulation utilizes fixed-width time intervals and updates the system state according to a stochastic process for the set …

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An Analysis Of Learning Curve Theory & Diminishing Rates Of Learning, Dakotah W. Hogan Mar 2020

An Analysis Of Learning Curve Theory & Diminishing Rates Of Learning, Dakotah W. Hogan

Theses and Dissertations

Traditional learning curve theory assumes a constant learning rate regardless of the number of units produced; however, a collection of theoretical and empirical evidence indicates that learning rates decrease as more units are produced in some cases. These diminishing learning rates cause traditional learning curves to underestimate required resources, potentially resulting in cost overruns. A diminishing learning rate model, Boones Learning Curve (2018), was recently developed to model this phenomenon. This research confirmed that Boones Learning Curve is more accurate in modeling observed learning curves using production data of 169 Department of Defense end-items. However, further empirical analysis revealed deficiencies …

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Meta Learning Recommendation System For Classification, Clarence O. Williams Iii Mar 2020

Meta Learning Recommendation System For Classification, Clarence O. Williams Iii

Theses and Dissertations

A data driven approach is an emerging paradigm for the handling of analytic problems. In this paradigm the mantra is to let the data speak freely. However, when using machine learning algorithms, the data does not naturally reveal the best or even a good approach for algorithm choice. One method to let the algorithm reveal itself is through the use of Meta Learning, which uses the features of a dataset to determine a useful model to represent the entire dataset. This research proposes an improvement on the meta-model recommendation system by adding classification problems to the candidate problem space with …

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Evaluation Framework For Cislunar Space Domain Awareness (Sda) Systems, Simon R. Knister Mar 2020

Evaluation Framework For Cislunar Space Domain Awareness (Sda) Systems, Simon R. Knister

Theses and Dissertations

Modern space missions are increasingly transiting cislunar space, requiring expansion of existing Space Traffic Management (STM) functions. Legacy Space Domain Awareness (SDA) systems were not purpose-built to detect and track cislunar objects, which could require acquisition of a new system of systems. There are numerous parameters that could be varied for each system, as well as the type and location of systems across the architecture. This research attempts to solve this problem by applying a model-based systems engineering (MBSE) approach to assess the performance and financial burden of a given system of systems. Fitness metrics are developed based upon the …

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Conduction Mapping For Quality Control Of Laser Powder Bed Fusion Additive Manufacturing, Chance M. Baxter Mar 2020

Conduction Mapping For Quality Control Of Laser Powder Bed Fusion Additive Manufacturing, Chance M. Baxter

Theses and Dissertations

A process was developed to identify potential defects in previous layers of Selective Laser Melting (SLM) Powder Bed Fusion (PBF) 3D printed metal parts using a mid-IR thermal camera to track infrared 3.8-4 m band emission over time as the part cooled to ambient temperature. Efforts focused on identifying anomalies in thermal conduction. To simplify the approach and reduce the need for significant computation, no attempts were made to calibrate measured intensity, extract surface temperature, apply machine learning, or compare measured cool-down behavior to computer model predictions. Raw intensity cool-down curves were fit to a simplified functional form designed to …

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Heuristic Approaches For Near-Optimal Placement Of Gps-Based Multi-Static Radar Receivers In American Coastal Waters, Brandon J. Hufstetler Mar 2020

Heuristic Approaches For Near-Optimal Placement Of Gps-Based Multi-Static Radar Receivers In American Coastal Waters, Brandon J. Hufstetler

Theses and Dissertations

Narcotics smuggling across the Caribbean Sea is a growing concern for the United States Coast Guard. One vector for this illicit trafficking is via small aircraft. This thesis proposes a multi-static radar architecture using the Global Positioning System (GPS) constellation as a transmission source to detect these aircraft as they transit a detection fence. The system developed in this thesis relies on the forward-scatter phenomenon in which a radar shadow is cast by a target as it crosses in front of a transmitter, creating a measurable difference in the signal amplitude at the receiver. This thesis first develops a mathematical …

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Vote Forecasting Using Multi-Objective Decision Analysis, Connor G. Crandall Mar 2020

Vote Forecasting Using Multi-Objective Decision Analysis, Connor G. Crandall

Theses and Dissertations

In December 2018, the United States Federal Government began what would become the longest government shutdown in U.S. history. This was the 21st shutdown since the adoption of the current appropriations process and 4th of the last decade. These shutdowns occur after government departments and agencies submit budget requests to Congress and the legislature is unable to come to an agreement to pass an appropriations bill. There is no clear solution to this problem. But this study hypothesizes that government departments and agencies could benefit from considering the political viability of their own budget requests prior to submitting them to …

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Recognizing Potential Cyberspace Warriors Through The Use Of Suspicion Propensity Index, Meghan G. Strang Mar 2020

Recognizing Potential Cyberspace Warriors Through The Use Of Suspicion Propensity Index, Meghan G. Strang

Theses and Dissertations

The Air Force currently suffers from excessively high attrition rates in the cyberspace career. The field is currently aiming to develop an entrance examination for the career, striving to improve personnel selection and decrease these high attrition rates. The attribute of suspicion is a key focus of the preliminary examination development, theorizing that it is a potential indicator present among competent cyber operators. This research makes use of the Suspicion Propensity Index (SPI), a reliable measure of one’s tendency to be suspicious, along with the highly cited Mayer’s trust questionnaire in order to compare the attributes that appear in successful …

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