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Articles 271 - 300 of 5698
Full-Text Articles in Engineering
Discerning Satellite Subsystem Costs To Improve Cost Estimation, Ryan A. Candella
Discerning Satellite Subsystem Costs To Improve Cost Estimation, Ryan A. Candella
Theses and Dissertations
The race for supremacy in the space environment is accelerating, with the United States taking a significant step by establishing its dedicated military branch for space operations. Achieving dominance in this realm relies on efficiently managing costs and securing rapid funding to initiate new programs. One step towards accomplishing this goal is to comprehend the cost distribution across the primary components of a Space Vehicle Bus and to delve into lower-level Work Breakdown Structure (WBS) elements for more precise and expeditious cost estimations. To achieve this, descriptive statistics for a variety of Bus subsystem WBS elements are provided in this …
Characterization Of Per- And Polyflouroalkyl Substances In Aqueous Filmforming Foam Wash Waters, John M. Diskin
Characterization Of Per- And Polyflouroalkyl Substances In Aqueous Filmforming Foam Wash Waters, John M. Diskin
Theses and Dissertations
The fiscal year 2020 National Defense Authorization Act mandated the publication of a military specification for a fluorine-free firefighting foam available for use no later than October 1, 2023. Replacing AFFF with a fluorine-free alternative creates the issue of decontaminating current firefighting infrastructure of residual PFAS without replacing these systems. To eliminate outstanding PFAS, the proposed solution is to drain the AFFF from current fire suppression systems and flush the plumbing three times with uncontaminated water. This study tested the efficacy of the triple rinse method by conducting scaled down experiments on a variety of plumbing components from a retired …
Machine Learning Predictions Of Electricity Transfers Between Balancing Authorities In The Carolinas, Victoria Groleau
Machine Learning Predictions Of Electricity Transfers Between Balancing Authorities In The Carolinas, Victoria Groleau
Theses and Dissertations
Climate change through reduced streamflow, increased temperatures, and other factors impacts the efficiency of energy generation systems. The United States electric grid is comprised of a large network of balancing authorities engaged in trading electricity to maintain balance between supply and demand. The generation of electricity, a pivotal component of this balance, is impacted by climate change and weather variability as well as the growing demand for energy. Several hydro climatological factors such as streamflow, air temperature, and wind speed significantly influence the efficiency of power plant electricity generation. Due to the exchange of electricity between balancing authorities, impacts to …
Long-Term Deterioration And Investment Modeling Of Water Distribution Infrastructure, Bethany M. Dorian
Long-Term Deterioration And Investment Modeling Of Water Distribution Infrastructure, Bethany M. Dorian
Theses and Dissertations
The United States Air Force (USAF) and municipal utilities rely on asset management processes to maximize utility of infrastructure assets while decreasing maintenance and repair costs. One of the core tenants of asset management is assessing the condition of the asset, which for water distribution pipes is challenging and costly to obtain. As a result, asset managers often rely upon pipe deterioration modeling using existing data, filling in the gaps when assessments are not available. This thesis uses USAF water distribution network data to develop a series of time-homogenous Markov chain probability models based on two sampling methods and four …
Development Of Cost Factors For Satellite Rechargeable Batteries, Katelyn A. Clements
Development Of Cost Factors For Satellite Rechargeable Batteries, Katelyn A. Clements
Theses and Dissertations
Factors are often used by the cost estimating profession to predict costs of future projects or project components. Cost factors can be useful when little to no cost data is available from which to build an initial estimate or as an easy-to-use cross check of a primary estimate. Specific to satellites, previous studies have examined cost factors at higher Work Breakdown Structure (WBS) levels (e.g., Level 2 or Level 3), while this research analyzes cost factors developed using data specific to rechargeable batteries at USCM WBS Level 4 and its parent, the Electrical Power System (EPS) at Level 3. Within …
Integrating Eod And Readiness Competencies Into The Ce Cgo Competency Framework, Kristina L. Johnson
Integrating Eod And Readiness Competencies Into The Ce Cgo Competency Framework, Kristina L. Johnson
Theses and Dissertations
In the last few years, the strategic focus of the United States defense posturing has shifted from legacy conflict in the Middle East to focusing on the Pacific with increased emphasis that Airmen must be educated and trained to deter or prevail in any conflict. To achieve this goal, the Department of Air Force (DAF) has evolved to utilizing a competency-based education framework with the Civil Engineer career field adopting this strategy and releasing the first version of their occupational competencies in 2020. However, DAF force posturing has evolved since 2020. With the new deployment system, Agile Combat Employment scheme …
A Statistical Analysis Of Phased Construction Projects, Timothy M. Dejong
A Statistical Analysis Of Phased Construction Projects, Timothy M. Dejong
Theses and Dissertations
The construction industry is known for exceeding target budgets and schedules, and Department of Defense projects are no exception. The Air Force Installation & Mission Support Center (AFIMSC) manages a budget of $3.14 billion to repair, alter, demolish, and maintain Air Force facilities. However, an ever-increasing backlog of maintenance and repair work and a consistently underfunded repair program pose an increased financial risk to the sustainability of the construction and repair program. Phasing large construction efforts is a potential strategy that has recently been used to yield efficiencies by AFIMSC program managers. This study presents a statistical analysis of phased …
Modeling Recovery Of The Florida Electric Transmission Grid After Severe Weather Event, Wei B. Guan
Modeling Recovery Of The Florida Electric Transmission Grid After Severe Weather Event, Wei B. Guan
Theses and Dissertations
Predicted changes to the climate are expected to increase the frequency and severity of extreme weather events. The Florida electric grid is a critical infrastructure system susceptible to severe weather events, especially hurricanes, causing widespread damage and outages. A foundational concept of the electric grid’s resilience is its ability to recover after extreme weather events, such as hurricanes and flooding. The recovery of the electrical grid after an extreme event is predicated upon the electrical asset's remoteness and the component's level of damage. Using fragility analysis, previous models have assessed the mean time to recover for transmission towers and substations …
Predictive Analytics For Military Construction Overruns: A Machine Learning Approach, William D. Hunter
Predictive Analytics For Military Construction Overruns: A Machine Learning Approach, William D. Hunter
Theses and Dissertations
This research focused on analyzing cost and schedule overruns in a specific set of Air Force MILCON projects. Using data from the Built Infrastructure Common Operating Picture (BICOP), several advanced machine learning techniques, including LASSO regression and Random Forest, were applied to uncover patterns and build predictive models. The work sought to enhance the decision-making capabilities and efficiency of project managers within the Air Force through data-driven insights. A key finding from the models indicated that location was the most important factor in influencing a project’s tendency toward cost and schedule overrun. The best model for predicting schedule overrun achieved …
Advanced Oxidation Of Tert-Butanol With Ultraviolet Light Emitting Diodes And Hydrogen Peroxide, Lauren R. Mainolfi
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 …
Quantifying Resilience And Redundancy For Air Force Linear Infrastructure, Ryan C. Jakovich
Quantifying Resilience And Redundancy For Air Force Linear Infrastructure, Ryan C. Jakovich
Theses and Dissertations
The historical underfunding of USAF infrastructure necessitates a strategic approach to reduce excess infrastructure while preserving resilience in the face of potential first-strike scenarios. This thesis formulates an infrastructure resilience metric that assesses network performance under varying degrees of damage. Furthermore, the study calculates the impact of redundant infrastructure by introducing added structural elements and measuring the resultant reduction in performance loss during damage scenarios. Utilizing USAF geospatial infrastructure data, adjacency matrices representing graph theory networks were constructed in Arc GIS Pro and evaluated using coding languages from the IGraph library and algorithms developed in RStudio. The newly proposed performance …
Optimizing Hub And Spoke Selections For Adaptive Basing In Agile Combat Employment, Alan Heng
Optimizing Hub And Spoke Selections For Adaptive Basing In Agile Combat Employment, Alan Heng
Theses and Dissertations
Advancing technologies and emerging competitors within the Indo-Pacific region have rendered the use of fixed installations for United States Air Force (USAF) operations less than optimal for generating airpower. The adoption of Agile Combat Employment (ACE) is imperative and emphasizes a hub-and-spoke model. However, the methodology for selection of contingency locations remains undecided. Current selection of optimal sites hinges on an optimization framework, employing either rank-based or mathematical approaches that consider various criteria to assess and quantify each location. These criteria are then addressed through objectives and constraints, forming the basis for an effective decision-making process. This paper introduces two …
An Assignment Model For Lateral Transfers Matching Base Repair Facilities To Xf3 Coded Nsns Requiring Repair, George D. Valaika
An Assignment Model For Lateral Transfers Matching Base Repair Facilities To Xf3 Coded Nsns Requiring Repair, George D. Valaika
Theses and Dissertations
This research addresses challenges in efficiently distributing reparable National Stock Numbers (NSNs) to base-level repair facilities, aiming to ease strain on depot resources. It establishes a network integrating bases with similar repair capabilities for NSNs and allocates NSNs to balance repair capacities. Drawing from USAF reparable inventory modeling and inventory management theory, it generates data mimicking historical data to maximize total expected part repairs by assigning NSNs based on the best percentage of base repair (PBR).
Artificial Intelligence And Perception: An Empirical Study, Anthony J. Neil
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.
A Framework For Dynamic Combat Support Exercises, Sean R. Mccarty
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.
A Model-Based And System-Theoretic Approach To Design Advanced Autonomy For Air Dominance Missions: A Loyal Wingman Case Study, Elizabeth S. Pennington
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 …
Applying Digital Engineering To Defense Acquisitions Through Model-Based Systems Engineering And Discrete Event Simulation, Michael T. Shutlock
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 …
Analyzing Cost Risk In Department Of Defense Program Office Estimates, Todd L. Millard
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 …
An Analysis Of Military Construction Cost Escalation And How It Is Accounted For In Cost Estimating Practices, Benjamin D. Rieben
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 …
An Analysis Of Usaf Policy Implementation For Building Information Modeling, Evan J. Ward
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 …
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
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 …
Root Cause Analysis For Troop Construction Schedule Delays And Cost Overruns, Richard H. Wilkens
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 …
Development Of A Metric To Quantify Facility Hardening, Jesse C. Solorzano
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 …
Accelerating Homomorphic Encryption In Risc-V Architectures With Hardware Based Number Theory Transform, Zachary Legg
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.
Analyzing The Effects Of Atmospheric Turbulence On Polarization-Entangled Photon Pairs Using Quantum State Tomography, Noah S. Everett
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. …
Synergistic Effects Of Neutron And Gamma Radiations On The Electrical Properties Of Mosfets, Jackson T. Piechowski
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 3.40x1010 neutrons/cm2 …
Training Schedule For The 56th Maintenance Group, Samantha K. O'Rourke
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, …
Standardization Of Risk Classifications For Unmanned Space Vehicle Missions, Collin A. Gwaltney
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 …
Investigation Of The Effect Of Internal Reynolds Number And Advective Capacity Ratio On Gas Turbine Film Cooling Parameters, John P. Di Lella
Investigation Of The Effect Of Internal Reynolds Number And Advective Capacity Ratio On Gas Turbine Film Cooling Parameters, John P. Di Lella
Theses and Dissertations
The desire for more powerful engines drives higher turbine inlet temperatures and a greater need to cool them. Experimentalists attempt to match cooling effectiveness between two conditions by matching several non-dimensional parameters, one of which is the coolant warming factor. The first investigation of this study examines the effect of the internal Reynolds number and the advective capacity ratio on the coolant warming factor by making use of a computational model and four different gases. It indicates the non-negligible and opposing effects of external convection and solid conduction on the coolant warming factor at matched internal Reynolds number and advective …
3- And 6-Degree-Of-Freedom Investigation Of Aerobraking To Support Cislunar And Planetary Operations, Erica C. Higginbotham
3- And 6-Degree-Of-Freedom Investigation Of Aerobraking To Support Cislunar And Planetary Operations, Erica C. Higginbotham
Theses and Dissertations
The first aerobraking experiment occurred in 1991 as part of the Hiten spacecraft’s cislunar survey mission, while the first non-Earth aerobraking experiment occurred in 1993 as part of the Magellan spacecraft’s mission to Venus. Although making only two trans-atmospheric passes to reduce its apogee altitude, the success of Hiten’s experiment led to the implementation of aerobraking by Magellan, reducing its orbit from elliptical to nearly circular over a span of 70 Earth days by leveraging aerodynamic drag to reduce its orbital energy via transiting the upper region of Venus’ atmosphere. The Magellan experiment helped prove the viability of aerobraking for …