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Articles 21001 - 21030 of 198087

Full-Text Articles in Engineering

Advanced Oxidation Of Tert-Butanol With Ultraviolet Light Emitting Diodes And Hydrogen Peroxide, Lauren R. Mainolfi Mar 2024

Advanced Oxidation Of Tert-Butanol With Ultraviolet Light Emitting Diodes And Hydrogen Peroxide, Lauren R. Mainolfi

Theses and Dissertations

Tert-butanol (TBA), a versatile chemical widely used in industrial processes, poses exposure risks through inhalation, ingestion, and skin contact. Environmental contamination, often from industrial activities, emphasizes the importance of robust waste management and monitoring to protect water supplies from potential TBA migration and ensure drinking water safety. This study employed hydrogen peroxide (H2O2): TBA molar ratios of 100, 200, 400, and 500:1 in a Continuous Flow Stirred-Tank Reactor (CSTR) with UV-LED as the TBA degradation mechanism in an Advanced Oxidation Process (AOP). The UV-LEDs and H2O2 were synergistically employed to generate hydroxyl radicals in an advanced oxidation process. Gas chromatography–mass …

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Assessing Military Parking: A Deep Learning Approach To Evaluating Standards And Impacts, Ryan D. Lalonde Mar 2024

Assessing Military Parking: A Deep Learning Approach To Evaluating Standards And Impacts, Ryan D. Lalonde

Theses and Dissertations

Current United States Department of Defense (DoD) standards require a minimum amount of parking for each building. This requirement defines how much off-street parking to construct. However, the impact of these requirements remains unclear. This study builds upon the emerging field of overhead imagery analytics by directly tying it to parking on military installations. Specifically, this study leverages a pretrained deep learning car detection model, Car Detection – USA, developed by Esri for use within ArcGIS, and couples it with open-access temporal imagery sourced from Google Earth Pro to assess selected parking lots across Area B, Wright-Patterson Air Force Base, …

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Level 2 Work Breakdown Structure Cost Growth Analysis, Kyle P. Marquis Mar 2024

Level 2 Work Breakdown Structure Cost Growth Analysis, Kyle P. Marquis

Theses and Dissertations

This thesis analyzes first and second level WBS elements of 59 historical USAF Acquisition Category I RDT&E programs for accuracy and influence on the overall program cost growth. For the accuracy analysis portion, the mean, 15th, and 85th percentiles of common practice estimates at completion are compared with the same percentiles for distributions generated using the data. The results reveal a trend of substantial underestimation of risks associated with cost overruns. For the influence portion, this thesis analyzes the effect that cost growth trends of different second level WBS elements have on cost growth of the overall program through regression …

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A Framework For Dynamic Combat Support Exercises, Sean R. Mccarty Mar 2024

A Framework For Dynamic Combat Support Exercises, Sean R. Mccarty

Theses and Dissertations

Future armed conflict will be characterized by the unknown as adversaries innovate and evolve—surprise is inevitable. Current exercises provide inadequate opportunities for combat support forces to develop improvisational skills. This research proposes an extensible framework for human-in-the-loop control of exercises using a graph network for modeling combined with topological analysis and the resource-constrained project scheduling problem. This framework is assessed using the United States Air Force Silver Flag exercise as a case study with promising results.

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Analyzing Cost Risk In Department Of Defense Program Office Estimates, Todd L. Millard Mar 2024

Analyzing Cost Risk In Department Of Defense Program Office Estimates, Todd L. Millard

Theses and Dissertations

This research studies cost risk for Department of Defense (DoD) acquisition programs during development and has three overarching objectives: 1) analyze the degree of change in cost risk (quantified as risk dollars) as programs mature, 2) analyze the accuracy of cost risk estimates (quantified as risk error) as programs progress, and 3) adopt risk analysis techniques common in the commercial banking industry to analyze cost risk in DoD programs. For the first objective, some evidence of significant positive trends in relative risk dollars is found for ACAT 1, 2, and 3 programs. For the second objective, there is no strong …

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Digital Airworthiness: Development Of A Sysml Based Framework For The Usaf Airworthiness Process, Justin T. Moore Mar 2024

Digital Airworthiness: Development Of A Sysml Based Framework For The Usaf Airworthiness Process, Justin T. Moore

Theses and Dissertations

In 2018 USAF decided to move towards a digital transition for programs and processes. To maximize the impact of initial transition efforts the airworthiness process was identified as a candidate for digital implementation. The airworthiness process is mandated for nearly every system or modification that flies. The airworthiness process identifies specific tasks that must be performed and artifacts that must be produced. This research worked to develop a framework that utilizes SysML to pattern these processes and the required artifacts. A system agnostic, importable library was developed using custom stereotypes and relationships for the purpose of application to digital system …

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Artificial Intelligence And Perception: An Empirical Study, Anthony J. Neil Mar 2024

Artificial Intelligence And Perception: An Empirical Study, Anthony J. Neil

Theses and Dissertations

This thesis investigates the impact of adjusting artificial intelligence explainability levels’ outputs on user perception. The overarching study extends within the Explainable Artificial Intelligence (XAI) domain. It examines a spectrum of variables, including performance, cognizance, familiarity, transparency, system bias, and the overall impact of AI, to understand their collective and individual effects that enable effective professional use in an organization. The study aims to illuminate the relationship between the degree of explainability provided by large language models such as ChatGPT, Bard, and Bing AI and the performance of these models when tasked with XAI adjustments.

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A Model-Based And System-Theoretic Approach To Design Advanced Autonomy For Air Dominance Missions: A Loyal Wingman Case Study, Elizabeth S. Pennington Mar 2024

A Model-Based And System-Theoretic Approach To Design Advanced Autonomy For Air Dominance Missions: A Loyal Wingman Case Study, Elizabeth S. Pennington

Theses and Dissertations

In contested air environments, safe coordination between decision-makers is paramount. Although the Department of Defense (DoD) prioritizes the development of Artificially Intelligent (AI) wingmen for air combat, a lack of methodology exists to design safe, holistic coordination between human and autonomous wingmen in the same environment. This thesis delivers a framework using Systems Theoretic Process Analysis Extended for Coordination (STPA-Coord) to analyze and design holistic coordination for the Loyal Wingman concept in an Air Dominance mission. STPA-Coord is a safety and hazard analysis process that uses Systems Theory to analyze and design coordination between decisionmakers in a system-of-systems architecture. Using …

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An Analysis Of Military Construction Cost Escalation And How It Is Accounted For In Cost Estimating Practices, Benjamin D. Rieben Mar 2024

An Analysis Of Military Construction Cost Escalation And How It Is Accounted For In Cost Estimating Practices, Benjamin D. Rieben

Theses and Dissertations

Construction escalation is a significant economic phenomenon that plays an important role in the construction industry. It refers to the steady increase in the costs associated with facility and infrastructure projects over time. Accurately capturing escalation is a key component in the development of construction cost estimates, and failure to adequately account for escalation can have far-reaching consequences. This is especially true for Military Construction (MILCON) projects, which account for billions of dollars of defense spending annually. The Department of Defense (DoD) utilizes a unit cost approach to develop rough order of magnitude (ROM) estimates for MILCON projects. The DoD …

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Applying Digital Engineering To Defense Acquisitions Through Model-Based Systems Engineering And Discrete Event Simulation, Michael T. Shutlock Mar 2024

Applying Digital Engineering To Defense Acquisitions Through Model-Based Systems Engineering And Discrete Event Simulation, Michael T. Shutlock

Theses and Dissertations

The U.S. Department of Defense (DoD) faces a critical challenge as acquisition professionals strive to grasp the intricacies of the acquisition process. This study proposes an innovative approach to cultivate a more informed and capable acquisition workforce through the integration of digital engineering, specifically Model-Based Systems Engineering (MBSE) and Discrete Event Simulation (DES) toolsets. Embracing digital transformation with MBSE provides a comprehensive understanding, implementing step-by-step procedures with an interface designed to handle vast amounts of information differently. The merging of MBSE's visual modeling with DES's dynamic simulation offers a holistic view, empowering acquisition professionals with robust planning and risk management …

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Development Of A Metric To Quantify Facility Hardening, Jesse C. Solorzano Mar 2024

Development Of A Metric To Quantify Facility Hardening, Jesse C. Solorzano

Theses and Dissertations

This research investigates the intricate aspect of infrastructure resilience, focusing on the distinction between hardening and resilience. Hardening, often used interchangeably, with enhancing resilience, involves strategies to strengthen facilities, networks, or systems against various threats. Despite its recognized importance in mitigating physical disruptions and enhancing facility functionality amid different threats, a significant vagueness persists in quantitatively defining hardening. This thesis addresses this gap by developing a quantifiable metric for facility hardening, separate from general resilience measures. The study begins by exploring the historical context of facility hardening, linked to catastrophic events and the need for resilient infrastructure. It explores various …

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Selection Of Soil Stabilization Methods For Low-Volume Road Applications, Peter J. Spinks Mar 2024

Selection Of Soil Stabilization Methods For Low-Volume Road Applications, Peter J. Spinks

Theses and Dissertations

This study examines a potential method of selecting an ideal soil additive to assist road planners in selecting an ideal soil stabilizer for low-volume road construction with in-situ soils. Essential for the socioeconomic success of rural communities, low-volume soil or gravel roads account for approximately 54% of US road expenditures to maintain and remediate. Soil stabilization can provide significant savings in regards to the cost, effectiveness, and environmental impacts of these roads. With hundreds of commercially available soil treatment products available with significant variations to their effects, it can be difficult for road planners to select the most appropriate product. …

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Deploying Field-Capable Genome Sequencing: Human Performance Considerations Under Various Personal Protective Equipment Ensembles, Steven A. Torres Mar 2024

Deploying Field-Capable Genome Sequencing: Human Performance Considerations Under Various Personal Protective Equipment Ensembles, Steven A. Torres

Theses and Dissertations

Field-portable genome sequencing enhances the Department of Defense's strategy for detecting biological threats, particularly in resource-limited environments. While current field-capable detection methods are effective, challenges in identifying emerging threats pose risks to personnel safety. As biotechnological advancements like portable nanopore genome sequencing can advance biological detection capabilities, the viability of conducting laboratory tasks under Mission-Oriented Protective Posture (MOPP) ensembles lacks sufficient data. This research assesses the effectiveness of tools like pipettes, centrifuges, vortexes, and nanopore sequencing within a MOPP ensemble. Novice participants were utilized to explore the extension of this capability, and they completed tasks in three conditions: Fatigues, Laboratory …

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Estimating Stimulated Raman Scattering Noise In Cwdm O-Band Channels Induced By Two Classical Dwdm Sources In A Quantum Network Fiber Segment, Kurt T. Spranger Ii Mar 2024

Estimating Stimulated Raman Scattering Noise In Cwdm O-Band Channels Induced By Two Classical Dwdm Sources In A Quantum Network Fiber Segment, Kurt T. Spranger Ii

Theses and Dissertations

The purpose of this research is to estimate the stimulated Raman scattering noise induced in CWDM O-band channels by two DWDM classical sources in a terrestrial quantum optical network containing classical and quantum optical signal coexistence in the same fiber segment. A use case is defined and analyzed which extracts a single fiber segment from a notional Bell state measurement found in a notional terrestrial quantum network. A stimulated Raman scattering noise model is employed in a Python simulation to estimate and rank-order the five O-band channels with the least amount of relative induced stimulated Raman scattering noise when given …

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Navigating Model-Based Systems Engineering (Mbse) Transition In The Department Of Defense (Dod): A Capability-Based Assessment (Cba) Use Case, Emily M. Tritschler Mar 2024

Navigating Model-Based Systems Engineering (Mbse) Transition In The Department Of Defense (Dod): A Capability-Based Assessment (Cba) Use Case, Emily M. Tritschler

Theses and Dissertations

The Department of Defense (DOD) wants to implement Model-Based System Engineering (MBSE) to accelerate and improve the acquisition process of increasingly complex systems. However, the department has not provided the necessary guidance on how to fully implement MBSE into our systems. This provided the following research opportunity: select a common DOD process, create an MBSE methodology, generate a model in accordance with that developed method, record the cost of modeling, and interview the model recipients to characterize their opinions on the investment. The research created a twelve-step methodology for application towards the gap analysis and characterization phase of a Capability-Based …

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An Analysis Of Usaf Policy Implementation For Building Information Modeling, Evan J. Ward Mar 2024

An Analysis Of Usaf Policy Implementation For Building Information Modeling, Evan J. Ward

Theses and Dissertations

The development of Building Information Modeling (BIM) has strongly influenced the architecture, engineering, and construction communities as a path towards effective and efficient asset management. Although BIM is a standard practice in the private sector, the United States Air Force (USAF) does not mirror its civilian counterparts when it comes to BIM use. USAF BIM is limited in its use and does not extend beyond the design and construction phases of the construction life cycle. This research used a detailed querying process to analyze foundational policy documents and determine specific USAF building information requirements. After categorizing the list of requirements …

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Root Cause Analysis For Troop Construction Schedule Delays And Cost Overruns, Richard H. Wilkens Mar 2024

Root Cause Analysis For Troop Construction Schedule Delays And Cost Overruns, Richard H. Wilkens

Theses and Dissertations

Troop construction can be an effective tool when a project is simple enough to execute projects in a timely and cost effective manner. However, underlying variables plague these projects causing them to miss anticipated deadlines which in return could make them more costly. Significant variables that convey impact to cost and schedule are Equipment Operating Issues, Edits During Construction, Design Flaws, Lack of Communication, Poor User Coordination, Improper Documentation, Inaccurate Submittals, Low Quality Control, and Lack of Experience. Project engineers and project managers must provide effective continuity as well as improve their own competence and situational awareness to effectively mitigate …

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Accelerating Homomorphic Encryption In Risc-V Architectures With Hardware Based Number Theory Transform, Zachary Legg Mar 2024

Accelerating Homomorphic Encryption In Risc-V Architectures With Hardware Based Number Theory Transform, Zachary Legg

Theses and Dissertations

Fully Homomorphic Encryption is an encryption paradigm enabling computations on encrypted data without the need for decryption. Such behavior is promising for securing DoD cloud computing but is also computationally demanding. To alleviate some of the computational load and accelerate FHE schemes, this research proposes adding a hardware accelerator, for the Number Theory Transform (NTT) operation, to a RISC-V processor. Thus enhancing FHE capabilities for potentially resource-constrained devices.

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Analyzing The Effects Of Atmospheric Turbulence On Polarization-Entangled Photon Pairs Using Quantum State Tomography, Noah S. Everett Mar 2024

Analyzing The Effects Of Atmospheric Turbulence On Polarization-Entangled Photon Pairs Using Quantum State Tomography, Noah S. Everett

Theses and Dissertations

To help in building a quantum-based communication link, we experimentally designed a system to simulate atmospheric turbulence and characterize its effects on a polarization-entangled photon-pair source. The simulated turbulence is constructed using two afocal optical systems with a phase plate inserted in each to mimic both weak and strong atmospheric turbulence respectively. After propagation, quantum state tomography (QST) is performed on each pair to reconstruct the density matrix of the pair’s overall polarization state. In characterization of the simulated turbulence, we were able to reach strengths up to a D/r0 of 18.2, which begins to approach the strong turbulent regime. …

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Radiological Decontamination Methodologies On Litter-Bound Patients In Arctic Environments, And The Associated Airborne Risks Posed To First Responders, Juan S. Alb Mar 2024

Radiological Decontamination Methodologies On Litter-Bound Patients In Arctic Environments, And The Associated Airborne Risks Posed To First Responders, Juan S. Alb

Theses and Dissertations

This study was conducted to determine if air-based decontamination (decon) methods would be effective at both treating patients exposed to dry, radiological contamination as well as reducing its re-aerosolization during the disrobing process, such that these methods could be applied on litter-bound patients in extreme cold environments. A litter-bound, full-size mannequin dressed in a set of standard military issue extreme cold weather jacket and pants coated in 27 g (1 Tbs) of Copper Oxide (density 6.315 g/cm3 ) was given one of three treatments for dry aerosol decon. The three cleaning treatments included high-efficiency particulate air (HEPA) vacuum, a …

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Synergistic Effects Of Neutron And Gamma Radiations On The Electrical Properties Of Mosfets, Jackson T. Piechowski Mar 2024

Synergistic Effects Of Neutron And Gamma Radiations On The Electrical Properties Of Mosfets, Jackson T. Piechowski

Theses and Dissertations

In many radiation environments, electronic assets are exposed to a wide variety of species of radiation. This thesis studies the effect of sequential exposure of MOSFETs to neutron and gamma radiation. 27 Goford Semiconductor GT060N04T MOSFETs with gate thickness ∼500 nm were exposed to gamma radiation from a Cesium-137 source and mixed gamma and neutron radiation from a Californium-252 source with total amounts of ionizing radiation dose, neutron fluence, and order of irradiation varied to determine if synergistic effects of neutron and gamma irradiation can be measured. Neutron fluence values as low as 3.45x109 and as high as 3.40x10 …

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Training Schedule For The 56th Maintenance Group, Samantha K. O'Rourke Mar 2024

Training Schedule For The 56th Maintenance Group, Samantha K. O'Rourke

Theses and Dissertations

The 56th Equipment Maintenance Squadron (56 EMS) provides equipment maintenance and back shop maintenance for the F-35 Joint Strike Fighter. The squadron executes thousands of sorties and flight hours annually. This operations tempo requires maintenance to prevent equipment failures, minimization of aircraft downtime, insurance of safety and compliance, and training of maintenance personnel. The squadron incorporates periodic training sessions to train maintenance personnel skills needed by airmen. This research investigates the optimization of these training sessions employing mixed integer programming (MIP). A multi-objective MIP model is developed to address the complex needs of various training activities, such as: training regiments, …

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Computational Analysis Of Transverse Jet Interactions On A Cone In Mach 3.9 Crossflow, Tia Massa Mar 2024

Computational Analysis Of Transverse Jet Interactions On A Cone In Mach 3.9 Crossflow, Tia Massa

Theses and Dissertations

The objective of this investigation was to analyze jet interactions using numerical simulations, which was compared to experimental data. A sharp cone with a 7-degree half-angle was modeled, along with the wind tunnel, using a 1:1 scale. Analysis of the data found the flow characteristics of the jet, including the bow shock and recirculation regions, were captured nicely in the CFD simulations, as well as the oblique shock off the nose of the cone. CFD simulations of the cone in a freestream environment depict shock-shock interactions not captured by experimental schlieren images. This research provides a rare glimpse into CFD …

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Generalized Characterization Of Biaxial Media Using Ultra-Wideband Multi-Static Focused Beam System With Polarimetric Calibration, Jeffrey P. Massman Mar 2024

Generalized Characterization Of Biaxial Media Using Ultra-Wideband Multi-Static Focused Beam System With Polarimetric Calibration, Jeffrey P. Massman

Theses and Dissertations

Novel metamaterial and metasurface realizations provide unique control of the electromagnetic wave dispersion but present many challenges for accurate constitutive parameter extraction. One measurement approach commonly employed is a freespace non-destructive focus beam system. Modern implementations are configured with multi-static dual-polarized capabilities for characterizing complex materials and offer many advantages by enabling ultra-wideband sampling, multiple measurement degrees of freedom and larger sample sizes. Practical electromagnetic material characterization of complex bianisotropic media requires the advancement of wave propagation analysis and calibration schemes. This research focuses on generalized biaxial media characterization and multi-static focused beam system metrology with polarimetric calibration schemes and …

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Life Cycle Analysis Of Mobile Nuclear Reactor Compared To Other Alternative Fuels In Indopacom, Maria J. Hurtado Mar 2024

Life Cycle Analysis Of Mobile Nuclear Reactor Compared To Other Alternative Fuels In Indopacom, Maria J. Hurtado

Theses and Dissertations

Energy is an item that makes the military vulnerable as it is something that they depend on the most which can have negative impacts. Mobile nuclear reactors are gaining the interest of many leaders in the military as a viable option of a potential alternative fuel source. There are many positives in utilizing mobile nuclear reactors in terms of environmental impacts and feasibility of transport. Studies have shown that mobile nuclear reactors can produce very low or negligible carbon emissions during operations. The focus of this thesis is to determine the environmental impacts of nuclear reactors, logistical requirements, and determine …

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Standardization Of Risk Classifications For Unmanned Space Vehicle Missions, Collin A. Gwaltney Mar 2024

Standardization Of Risk Classifications For Unmanned Space Vehicle Missions, Collin A. Gwaltney

Theses and Dissertations

This paper seeks to model risk classification levels (A-D) for 122 Space Vehicle programs. Models include multinomial logistic regression as well as random forest, a machine learning technique based on decision trees. We use independent variables (IVs) which are theoretically correlated to risk class for the regression and one random forest model. We then include all IVs and allow the random forest technique to use those which provide the most information on risk class before paring down the number of IVs to only 7. We show that the accuracy of predictions increases from 62% to 87% by using random forest …

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An Investigation Of Torso Muscle Fatigue And Its Relation To Discomfort During Vertical Vibration Exposure, Nathan H. Hodges Mar 2024

An Investigation Of Torso Muscle Fatigue And Its Relation To Discomfort During Vertical Vibration Exposure, Nathan H. Hodges

Theses and Dissertations

Military and civilian helicopter pilots often experience back pain attributed to vibration exposure during flight and sustained poor posture, known as the "helicopter hunch." This study investigated torso muscle activation using surface electromyography (EMG) to assess the relationship between discomfort and muscle fatigue. Eight subjects were exposed to different vibration frequencies over two-hour periods, with EMG data collected every five minutes. Significant differences in muscle activation were observed before and after vibration exposure, suggesting increased muscle activation during vibration compared to prolonged seating alone. Discomfort surveys indicated higher discomfort during vibration.

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Human Performance Modeling Architecture With Hc-130j Mission Application, Stephanie G. Slimp Mar 2024

Human Performance Modeling Architecture With Hc-130j Mission Application, Stephanie G. Slimp

Theses and Dissertations

The DOD emphasizes digital engineering using Model-Based Systems Engineering (MBSE), where MBSE includes SysML-based models of systems. Analysis of system impacts on the human operators and their performance typically occurs through non-MBSE approaches, if at all. One current process, considered the As-Is process for this research, evaluates human performance and workload using IMPRINT, a discrete event simulation (DES) tool. IMPRINT primarily exists as a standalone tool with limited built-in functionality to integrate with an MBSE tool. Using the HC-130J and its crew during a CSAR mission as the system, this research develops a generalizable and updateable human performance modeling architecture …

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Rotorcraft Assisted Aircraft Inspection System: Creation And Component Assessment, Adam J. Warren Mar 2024

Rotorcraft Assisted Aircraft Inspection System: Creation And Component Assessment, Adam J. Warren

Theses and Dissertations

Aircraft require frequent inspections to perform their missions safely. Current visual inspection methods are time-consuming and dangerous for inspection personnel, but they are necessary to spot flaws that could endanger the aircraft during flight. This research explores a set of methods for transforming a set of target inspection criteria into camera specifications that will allow a UAS aircraft inspection system to perform inspections on the top skin of an aircraft. Given the minimum distance for the UAS to fly above the aircraft, minimum flaw size to search for on the aircraft, minimum number of pixels to display that flaw size, …

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Utilization Of The System Engineering Design Process To Design And Test A Low-Cost Infectious Aerosol Control Mechanism For Patient Aeromedical Evacuation, Sara Shaghaghi Mar 2024

Utilization Of The System Engineering Design Process To Design And Test A Low-Cost Infectious Aerosol Control Mechanism For Patient Aeromedical Evacuation, Sara Shaghaghi

Theses and Dissertations

The aeromedical evacuation of military patients is a critical component of care for Armed Forces members. The Air Force’s ability to transport patients relies on the technology and systems available. A vital transport responsibility is keeping the patient and medical personnel safe during transport. The historical and legacy systems provide reliable transport mechanisms for the Armed Forces’ patients infected with high-level biological agents, but drawbacks must be considered. This dissertation will discuss the development, conceptual design, and initial evaluation of a new low-cost, litter-mounted patient transport system, Biological-Mitigation in Patient Transport (B-MIPT), using the “V” model of the system engineering …

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