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Articles 4531 - 4560 of 11510

Full-Text Articles in Engineering

Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber Mar 2018

Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber

Theses and Dissertations

Modern militaries rely upon remote image sensors for real-time intelligence. A typical remote system consists of an unmanned aerial vehicle, or UAV, with an attached camera. A video stream is sent from the UAV, through a bandwidth-constrained satellite connection, to an intelligence processing unit. In this research, an upgrade to this method of collection is proposed. A set of synthetic images of a scene captured by a UAV in a virtual environment is sent to a pipeline of computer vision algorithms, collectively known as Structure from Motion. The output of Structure from Motion, a three-dimensional model, is then assessed in …

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Expected Coverage (Excov): A Proposal To Compare Fuzz Test Coverage Within An Infinite Input Space, Evan V. Swihart Mar 2018

Expected Coverage (Excov): A Proposal To Compare Fuzz Test Coverage Within An Infinite Input Space, Evan V. Swihart

Theses and Dissertations

A Fuzz test is an approach used to discover vulnerabilities by intentionally sending invalid inputs to a system for the purpose of triggering some type of fault or unintended effect that renders the system vulnerable to an exploit. Fuzz testing is an important cyber-testing technique used to find and fix vulnerabilities before they are exploited. The fuzzing of military data links presents a particular challenge because existing fuzzing tools cannot be easily applied to these systems. As a result, the tools and techniques used to fuzz these links vary widely in sophistication and effectiveness. Because of the infinite, or nearly …

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Securing Data In Transit Using Two Channel Communication, Clark L. Wolfe Mar 2018

Securing Data In Transit Using Two Channel Communication, Clark L. Wolfe

Theses and Dissertations

Securing data in transit is critically important to the Department of Defense in todays contested environments. While encryption is often the preferred method to provide security, there exist applications for which encryption is too resource intensive, not cost-effective or simply not available. In this thesis, a two-channel communication system is proposed in which the message being sent can be intelligently and dynamically split over two or more channels to provide a measure of data security either when encryption is not available, or perhaps in addition to encryption. This data spiting technique employs multiple wireless channels operating at the physical layer, …

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Flightline Heroics And The Façade Of A Healthy Common Support Equipment Fleet, Benjamin D. Bobic Mar 2018

Flightline Heroics And The Façade Of A Healthy Common Support Equipment Fleet, Benjamin D. Bobic

Theses and Dissertations

Access to serviceable support equipment enables aircraft maintenance crews the ability to efficiently keep assigned aircraft safe and mission capable. Current Air Force policy does not require formal management and enterprise fleet health reporting of serialized support equipment. As such, articulating funding requirements to replace equipment has been a challenge for equipment managers. To better articulate support equipment requirements, equipment managers need quantifiable support equipment data. A previous study examined the relationship between aircraft availability and support equipment availability. While finding no significant correlation, the author identifies the practices of "Frankensteining" and "Beg-Borrow-Steal" as possible reasons for the absence of …

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Evaluating Contingency Construction Methods: A Delphi Study, William E. Bentley Mar 2018

Evaluating Contingency Construction Methods: A Delphi Study, William E. Bentley

Theses and Dissertations

The purpose of this research was to evaluate which existing RED HORSE vertical construction system was “best” suited for contingency operations and the relative pros/cons/challenges associated with each. RED HORSE units, having existed for over 50 years, currently have 4 active duty squadrons currently employed overseas in multiple military contingency environments. Based on site visits, it was established that the Ultimate Building Machine (UBM)/K-Span, Professionally Engineered Buildings (PEB), and the FrameCAD system are the three most prevalent vertical construction systems/methods in use by RED HORSE. Fourteen Subject Matter Experts (SME) from across the Air Force participated in a Delphi study …

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Defining Success In Air Force Infrastructure Asset Management Through Use Of The Delphi Method, Brendan J. Maestas Mar 2018

Defining Success In Air Force Infrastructure Asset Management Through Use Of The Delphi Method, Brendan J. Maestas

Theses and Dissertations

Asset Management has a history of policy mandates within the US Government dating back to 1990’s. In order to accomplish these many directives, the Air Force Civil Engineer community has adopted a mindset and framework commonly referred to as Asset Management. Despite numerous references and guidance to establish Asset Management principles, the Air Force has not yet developed a clear and concise way to define or measure overarching success in Asset Management. This research effort focuses on closing the knowledge gap between issued policy and implementation. It examines Asset Management implementation efforts in other government agencies, private industries, and in …

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Cost And Performance Difference Of High Performance Sustainable Buildings, Philip A. Ramsey Mar 2018

Cost And Performance Difference Of High Performance Sustainable Buildings, Philip A. Ramsey

Theses and Dissertations

Varying legislation and executive orders coupled with needs for energy resiliency have led the United States Air Force to pursue sustainable construction. The limited understandings of initial costs to implement these changes have contributed to poor project cost estimating and changed implementation of legal requirements. A student t-test for populations with unequal variance was accomplished on the final normalized contract cost of 1628 Air Force Military Construction (MILCON) projects executed between 2002 and 2017. Future design considerations for net zero energy buildings were compiled from a net zero energy residential community in Fontana, California. There was no statistically significant difference …

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Conceptual Systems Security Analysis Aerial Refueling Case Study, Martin Trae Span Iii Mar 2018

Conceptual Systems Security Analysis Aerial Refueling Case Study, Martin Trae Span Iii

Theses and Dissertations

In today’s highly interconnected and technology reliant environment, systems security is rapidly growing in importance to complex systems such as automobiles, airplanes, and defense-oriented weapon systems. While systems security analysis approaches are critical to improving the security of these advanced cyber-physical systems-of-systems, such approaches are often poorly understood and applied in ad hoc fashion. To address these gaps, first a study of key architectural analysis concepts and definitions is provided with an assessment of their applicability towards complex cyber-physical systems. From this initial work, a definition of cybersecurity architectural analysis for cyber-physical systems is proposed. Next, the System Theory Theoretic …

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A Study Of The Air Force Airworthiness Assessment Process With Recommendations For Reusable Launch Vehicles, Austin A. Troya Mar 2018

A Study Of The Air Force Airworthiness Assessment Process With Recommendations For Reusable Launch Vehicles, Austin A. Troya

Theses and Dissertations

Flight safety is a critical design and engineering consideration within the United States Department of Defense (DoD) and particularly the United States Air Force (USAF). This study conducts an independent evaluation of the airworthiness assessment process used by the United States Air Force’s Engineering Directorate through modeling and simulation. The airworthiness process is examined for its ability to effectively verify sound engineering design and efficiency with respect to the implementation of new software-based assessment tools and its impact on timeliness of reviews and resource utilization. Simulation results guide recommendations for reducing non-value-added activities and strategic leveling of resource demands to …

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Land Cover Influences On Airborne Noise Propagation At Usaf Installations, Ariel L. Waiters Mar 2018

Land Cover Influences On Airborne Noise Propagation At Usaf Installations, Ariel L. Waiters

Theses and Dissertations

Mitigation of aircraft noise and encroachment by residential areas at various U.S. military installations remains a challenge and hampers effective military operations. The Air Force has established standard practices that utilize computational noise models to generate and display noise propagation from military installations. Despite great advances in models and mitigation action plans, the current USAF Noisemap modeling tool and methods do not consider the effects of variation in land cover. Moreover, such limitations could greatly affect the accuracy of predicting aircraft noise pollution. The standard modeling method assumes a ground cover impedance of 225 Kpa*s/m2, which …

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An Open Source Approach To Social Media Data Gathering, Anthony J. Kallhoff Mar 2018

An Open Source Approach To Social Media Data Gathering, Anthony J. Kallhoff

Theses and Dissertations

Modern usage of social media affords the military intelligence and analytic communities novel approaches to gather information. However, the tools and resources to develop these methodologies are still maturing. Furthermore, current data acquisition tools are not available to the DoD for all social media platforms. This thesis addresses a small subset of this problem by developing an open source methodological approach to collect and manage data from a popular social media site that has previously been inaccessible to defense intelligence organizations. This approach was operationalized via the R package called instaExtract, and an exemplar analysis was performed to demonstrate its …

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Market Basket Analysis With Shortened Web Link Click Data, James C. Gallagher Mar 2018

Market Basket Analysis With Shortened Web Link Click Data, James C. Gallagher

Theses and Dissertations

Market research is an indispensable part of an organization's ability to understand market dynamics in an area. Over the past 20 years data collection and analysis through Knowledge Discovery through Databases (KDD) has arisen to supplement the traditional methods of surveys and focus groups. Market Basket Analysis is an area of KDD that identifies associations between commonly purchased items. As social media use has grown, link shortening companies help users share links in a constrained space environment and, in exchange, collect data about each user when a link is clicked. This research applies market basket analysis techniques with graph mining …

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Scheduling Tool For The Nevada Test And Training Range, Miguel J. Macias Mar 2018

Scheduling Tool For The Nevada Test And Training Range, Miguel J. Macias

Theses and Dissertations

Presently, the 57th Wing Scheduler at Nellis AFB schedules daily mission requests to the Nevada Test and Training Range (NTTR) airspace manually. The process is time consuming and may lead to suboptimal range resource allocations. The goal of this study is to provide the scheduler with an automated scheduling approach that will improve range scheduling efficiency. The tool developed uses range request data from units at Nellis AFB to produce daily mission schedules for a month long scheduling horizon with Microsoft VBA code and a commercial Integer Program (IP) solver. Under our current understanding of scheduler priorities, we formulate the …

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Experimental Designs, Meta-Modeling, And Meta-Learning For Mixed-Factor Systems With Large Decision Spaces, Zachary C. Little Mar 2018

Experimental Designs, Meta-Modeling, And Meta-Learning For Mixed-Factor Systems With Large Decision Spaces, Zachary C. Little

Theses and Dissertations

Many Air Force studies require a design and analysis process that can accommodate for the computational challenges associated with complex systems, simulations, and real-world decisions. For systems with large decision spaces and a mixture of continuous, discrete, and categorical factors, nearly orthogonal-and-balanced (NOAB) designs can be used as efficient, representative subsets of all possible design points for system evaluation, where meta-models are then fitted to act as surrogates to system outputs. The mixed-integer linear programming (MILP) formulations used to construct first-order NOAB designs are extended to solve for low correlation between second-order model terms (i.e., two-way interactions and quadratics). The …

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Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness On A Flat Plate, Jacob P. Fischer Mar 2018

Influence Of Coolant Flow Rate Parameters In Scaling Gas Turbine Cooling Effectiveness On A Flat Plate, Jacob P. Fischer

Theses and Dissertations

Effective film cooling relies on the performance of the selected cooling hole shape and placement of the holes on the surface of the blade. To test each holes effectiveness, large scale, low-temperature testing has been used to reduce cost and complexity. The resulting quantity from this testing is called the adiabatic effectiveness (n). The adiabatic effectiveness can then scaled up to engine operating conditions to predict how the selected film cooling hole will perform. This process is complicated by the nonlinear variation of gas properties between coolant and freestream conditions as well as between the experimental and engine conditions. In …

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Comparison Of Traditional Versus Cubesat Remote Sensing: A Model-Based Systems Engineering Approach, Daniel L. Cipera Mar 2018

Comparison Of Traditional Versus Cubesat Remote Sensing: A Model-Based Systems Engineering Approach, Daniel L. Cipera

Theses and Dissertations

This thesis compares the ability of both traditional and CubeSat remote sensing architectures to fulfill a set of mission requirements for a remote sensing scenario. Mission requirements originating from a hurricane disaster response scenario are developed to derive a set of system requirements. Using a Model-based Systems Engineering approach, these system requirements are used to develop notional traditional and CubeSat architecture models. The technical performance of these architectures is analyzed using Systems Toolkit (STK); the results are compared against Measures of Effectiveness (MOEs) derived from the disaster response scenario. Additionally, systems engineering cost estimates are obtained for each satellite architecture …

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Internet Of Things For A Smart Transportation System, Ahmed Yahya Awad Mar 2018

Internet Of Things For A Smart Transportation System, Ahmed Yahya Awad

Theses and Dissertations

Today, school buses transport millions of students to and from schools. Therefore, the safety of school students is still a hot topic and the most imperative issue. The evolution of wireless location-based services has created consumer requests for the availability of global positioning systems (GPS) in urban and indoor environments. Nowadays, there is a requirement to improve a monitoring system for the school bus, that monitors its location and speed. This work investigates two different ways to track the vehicle through ordinary GPS or Assisted-GPS (A-GPS). A-GPS improves startup performance (time-to-first-fix (TTFF)), of a GPS satellite-based positioning system in the …

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A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity, Anthony A. Castello Mar 2018

A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity, Anthony A. Castello

Theses and Dissertations

The research this paper focuses on is comparing the structural differences between the icosahedron and hexakis icosahedron frame and skin for use as a vacuum lighter than air vehicle (VLTAV), analyzing the stress concentrations in the hexakis icosahedron both with and without the skin, and finding the optimal location and size of the air evacuation method for creating the internal vacuum. Previous research to date has identified dynamic loading on the structure and optimization of the structure, but this will be the first research to analyze the manufacturing of the structure through the development of the air evacuation design. Findings …

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Study Of Abnormal Grain Growth In Beta Annealed Ti-6al-4v Forgings, Lee R. Morris Mar 2018

Study Of Abnormal Grain Growth In Beta Annealed Ti-6al-4v Forgings, Lee R. Morris

Theses and Dissertations

Beta annealed Ti-6Al-4V has been used extensively in current aerospace platforms due to properties such as high strength to weight ratio. Recent inspections during aircraft production have revealed regions of excessive grain sizes, resulting in quarantined parts and excessive time spent on root cause analysis and risk mitigation efforts. Uncertainty surrounding these parts has led to increased costs and may cause future aircraft production delays. Part manufacturers have intermittently reported problems with abnormal grain growth in these alloys for years, but to date no supplier has been able to determine the source of this microstructural phenomenon. Leveraging common Finite Element …

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Analysis Of Additively Manufactured Injectors For Rotating Detonation Engines, Michael C. Waters Mar 2018

Analysis Of Additively Manufactured Injectors For Rotating Detonation Engines, Michael C. Waters

Theses and Dissertations

This research represents an experimental and computational analysis of additively manufactured injectors for Rotating Detonation Engines (RDEs) for use in rocket propulsion. This research was based on the manufacture and testing of existing injector element designs using additive techniques. The designs were modeled from geometries gathered from Sutton and Biblarz Elements of Rocket Propulsion [23]. The goal of this research was to characterize the viscous losses of each design based on the discharge coefficient. The designs were computationally simulated to gain insight to the flow characteristics using multiple sets of conditions for surface roughness and inlet pressure. The results were …

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Organizimi I Ndërtimit Të Fushës Sportive Në Fshatin Bolevc Të Komunës Së Kamenicës, Shqiprim Thaqi Mar 2018

Organizimi I Ndërtimit Të Fushës Sportive Në Fshatin Bolevc Të Komunës Së Kamenicës, Shqiprim Thaqi

Theses and Dissertations

Menaxhimi dhe shkenca e organizimit të ndërtimit ka rëndësi të madhe për zhvillimin e një shoqërie bashkëkohore. Menaxhimi nëpërmjet planifikimit, organizimit, udhëheqjes dhe kontrollit të resurseve organizative, arrin qëllimin organizativ në mënyrë efikase. Të gjitha teknikat e menaxhimit fillojnë nga stili kooperativ i udhëheqjes si teknika të ndërmarrjes. Qëllimi kryesor i këtij studimi është që të analizohet mënyra e organizimit të një projekti ndërtimor me profesionalizëm sipas standardeve dhe rregullave ndërtimore. Si duhet të bëhet organizimi i mirëfilltë i një projekti ndërtimor duke përfshirë punimin e paramasës dhe parallogarisë, si dhe të planeve dinamike? Cila është mënyra e punës dhe …

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Teknologjia E Kubëzave Të Betonit, Mevlide Toska Mar 2018

Teknologjia E Kubëzave Të Betonit, Mevlide Toska

Theses and Dissertations

Kjo temë diskuton ndikimin e betonit në jetën e njerëzve e cila mund të themi se është bëre pjesë e pandashme e njeriut, më gjerësisht kjo temë fokusohet në kubëzat e betonit, në aplikimin e tyre në Kosovë, prodhimi i tyre se në cilën mënyre bëhet, si dhe hapat të cilat duhet kaluar për prodhimin e tyre, përdorimin e aditivëve, dhe elementeve tjera përbërëse për një prodhim sa më kualitativ të teknologjisë së kubëzave. Prodhimi i betonit, poashtu është duke u zhvilluar në hapa të shpejte, dhe me përdorim të madh në tregun Kosovar,pasi që kemi një zhvillim të hovshëm …

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Effects Of Position Uncertainty On Passive Multistatic Sar Resolution Measures, Duy K. Nguyen Mar 2018

Effects Of Position Uncertainty On Passive Multistatic Sar Resolution Measures, Duy K. Nguyen

Theses and Dissertations

Given numerous exciting potentials including substantial cost savings, passive multistatic synthetic aperture radar (PMSAR) has been gaining more attention in the radar community. However, PMSAR research efforts such as emitters of opportunity selection thus far have not considered radar position uncertainty. Seeking to fill this knowledge gap, we run Monte Carlo trials to simulate transmitter position uncertainty and examine the effects on the multistatic resolution of radar sets of different geometries, center frequencies and bandwidths. By monitoring the 3dB contour of the multistatic point spread function, we find that the multistatic resolution worsens on average and the data spread grows …

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Computational Investigation Using Bleed As A Method Of Shock Stabilization, Dayle L. Chang Mar 2018

Computational Investigation Using Bleed As A Method Of Shock Stabilization, Dayle L. Chang

Theses and Dissertations

Shock-wave/boundary layer interactions (SWBLI) produce undesirable dynamic loads and separated unsteady flows, adversely impacting the performance and structural integrity of supersonic vehicles. Computational fluid dynamics (CFD) is a successful tool in experimental planning and shows promise as a critical tool in understanding and mitigating negative effects of SWBLI. The goal of this research is to demonstrate the effect of bleed holes on shock stability using the OVERFLOW CFD solver to inform the planning of an Air Force Research Laboratory (AFRL) SWBLI wind tunnel experiment. First, a two-dimensional, flat plate, single-hole configuration was developed. Massflow discrepancies of 14.8% were initially observed …

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Space-Based Maneuver Detection And Characterization Using Multiple Model Adaptive Estimation, Justin D. Katzovitz Mar 2018

Space-Based Maneuver Detection And Characterization Using Multiple Model Adaptive Estimation, Justin D. Katzovitz

Theses and Dissertations

An increasingly congested space environment requires real-time and dynamic space situational awareness (SSA) on both domestic and foreign space objects in Earth orbits. Current statistical orbit determination (SOD) techniques are able to estimate and track trajectories for cooperative spacecraft. However, a non-cooperative spacecraft performing unknown maneuvers at unknown times can lead to unexpected changes in the underlying dynamics of classical filtering techniques. Adaptive estimation techniques can be utilized to build a bank of recursive estimators with different hypotheses on a system's dynamics. The current study assesses the use of a multiple model adaptive estimation (MMAE) technique for detecting and characterizing …

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Quasi-Static Nonlinear Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Kyle D. Moore Mar 2018

Quasi-Static Nonlinear Analysis Of A Celestial Icosahedron Shaped Vacuum Lighter Than Air Vehicle, Kyle D. Moore

Theses and Dissertations

Due to the many drawbacks associated with a traditional lighter than air vehicle (LTAV), there is a desire for a LTAV which generates lift from an internal vacuum. To date, two feasible designs (the icosahedron and the hexakis icosahedron) for this so called vacuum lighter than air vehicle (VLTAV) have been studied at the Air Force Institute of Technology (AFIT). This research looks to show the feasibility of a new design for a VLTAV, the celestial icosahedron. This research includes a boundary condition study which proves the symmetric nature of the celestial icosahedron's frame with laterally constrained and unconstrained vertices. …

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Techniques For Low-Latency In Software-Defined Radio-Based Networks, Daniel D. Hart Mar 2018

Techniques For Low-Latency In Software-Defined Radio-Based Networks, Daniel D. Hart

Theses and Dissertations

Decreased budgets have pushed the United States Air Force towards using existing systems in new ways. The use of unmanned aerial vehicle swarms is one example of reuse of existing systems. One problem with the increased utilization of these swarms is the congestion of the electromagnetic spectrum. Software-defined or cognitive radios have been proposed as a basis for a potential robust communications solution. The present research aims to develop and test a genetic algorithm-based cognitive engine to begin looking at real-time engines that could be used in future swarms. Here, latency is the optimization objective of primary importance. In testing …

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Navigation Using Vector And Tensor Measurements Of The Earth's Magnetic Anomaly Field, Lauren A. Mount Mar 2018

Navigation Using Vector And Tensor Measurements Of The Earth's Magnetic Anomaly Field, Lauren A. Mount

Theses and Dissertations

This research explores the viability of using a navigation system that relies on measurements of the magnetic anomaly field as an alternative to GPS navigation. Previous research has been conducted on developing a navigation system using the intensity of the Earth's magnetic anomaly field as an alternative signal. This research focuses on using vector and tensor measurements, as opposed to scalar measurements of the anomaly field, as a means of obtaining accurate position and orientation solutions. This paper presents two navigation systems. The first uses an Extended Kalman Filter (EKF) with vector measurements of the magnetic anomaly field to aid …

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They're Only Nuclear Weapons: An Exploratory Analysis Of Safety Climate Within The Nuclear Enterprise, Brandon M. Clements Mar 2018

They're Only Nuclear Weapons: An Exploratory Analysis Of Safety Climate Within The Nuclear Enterprise, Brandon M. Clements

Theses and Dissertations

By possessing nuclear weapons, the United States Air Force is inherently exposed to extreme safety concerns. With multiple setbacks in recent years (e.g., unauthorized transport of nuclear weapons, cheating scandals, and career dissatisfaction), some have begun to wonder how safe the nuclear enterprise truly is. Building upon the concept of safety climate, this study explores safety climate constructs and trends associated with current nuclear maintenance safety climate survey data.

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Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler Mar 2018

Utilizing Supercomputing To Analyze Risks Of An Emergent Large-Scale Debris Field In Low Earth Orbit, David J. Buehler

Theses and Dissertations

The likelihood of on-orbit breakups, whether spontaneous or the result of collision, will likely continue to grow as the barriers of entry to and use of space are reduced. In all orbital regimes, especially low Earth orbit (LEO), preparation to respond quickly when the next breakup occurs is critical. This research utilizes high-performance parallel computation along with python-driven Systems Tool Kit (STK) to model a large-scale on-orbit breakup in LEO, with the goal of returning data in less than 90 minutes. The breakup is characterized by the National Aeronautics and Space Administration (NASA) EVOLVE 4.0 breakup model and is both …

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