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Modeling Recovery of the Florida Electric Transmission Grid After Severe Weather Event
Get PDFPredicted 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\u27s remoteness and the component\u27s level of damage. Using fragility analysis, previous models have assessed the mean time to recover for transmission towers and substations and their failure rates under various storm scenarios. The present study utilizes a stochastic method and component-level data to assess the remoteness and recoverability of 17,026 electrical transmission towers and 176 substations in a nine-county region of the Florida Panhandle. The results of this study identify the expected outages and recovery time from multiple simulated hurricane events using fragility analysis. The study assesses recovery via the number of customers experiencing a decrease in the level of service under various damage scenarios. The outcome of this study will help inform disaster management planning and resilient infrastructure investment
Exploring Fiscal Year Budget Assessments: A Look at SBIR/STTR and Congressional Rescissions
Get PDFThis study examines the relationship between acquisition programs within the Air Force Life Cycle Management Center (LCMC) and budgetary assessments from both the Small Business Innovation Research and Small Business Technology Transfer (SBIR & STTR) programs, as well as Congressional Rescissions. It analyzes the tendency and severity of budget cuts across different programs, considering factors such as completion time, budget activities, and a variable akin to true Acquisition Category (ACAT) levels. Key findings include a significant difference in the rates of proportion of programs assessed between appropriations 3010 (23.65%) and 3600 (67.05%) from fiscal years 2010-2023. The research indicates a higher stability and predictability in SBIR/STTR assessments compared to Congressional Rescissions, advising against planning for the latter due to unpredictability. The analysis also updates and expands upon a 2016 study, providing a more current understanding of assessment rates and offering refined budget planning recommendations for LCMC cost estimators. Specifically, it suggests different expected cut percentages for appropriations 3600 and 3010 when assessments are applied to every program in a peanut butter spread method for a more accurate forecasting in current fiscal environments. The study\u27s analysis of appropriations for the Air Force Life Cycle Management Center (LCMC) from 2010-2023 updates and extends a 2016 study, offering new budget planning recommendations based on recent data. The 2016 study advised expecting a weighted mean cut of 2.21% for appropriations 3600 overall, 2.62% for 3600 SBIR/STTR, and 2.18% for 3010. In contrast, the current study suggests planning for a weighted mean cut of 3.08% for appropriations 3600 in general, 2.10% for 3600 SBIR/STTR, and a notably higher 4.55% for 3010, reflecting changes in budgetary assessment trends and providing more accurate guidance for cost estimators within the LCMC
An Empirical Study on the Transfer of Virtual Reality Assembly Training
Get PDFVirtual Reality technology provides new opportunities for enhanced training in a variety of career field. An important feature of any training is whether the knowledge and skills learned transfer to real world work performance. Scholars call this Training Transfer. In this study, a novel approach to measuring training transfer of a Virtual Reality assembly training is designed and executed. 23 Subjects were recruited for this human subject experiment. The findings indicate that training transfer was not significantly different between VR and traditional training, however factors such as affective cognitive consistency, task complexity, perceived task workload, and conscientiousness contributed to training transfer
Feasibility of a Zero-Length Spring Gravimeter for Use in Portal Monitoring
Get PDFIn recent years, gravimeters have become sensitive enough to theoretically measure masses of interest at distances relevant for portal monitoring. Characterizing the re[1]sponse of the gravimeter to close range masses across a large solid angle is necessary before attempting to demonstrate a portal-monitoring-like measurement due to this mission being outside the scope of typical gravimeter operations. The characterization of the gravimeter focused on three primary topics. For the position-dependent bias, it is found that the models used overestimate the expected observed gravity when the test mass is closest to the gravimeter in four out of seventeen experiments and under[1]estimate the expected gravity in five out of seventeen experiments. An experiment to determine spatial resolution was able to resolve masses that are ∼ 2.7 times farther apart than the stand off distance. The mean standard deviations individually ranged from 0.92 µGal to 3.33 µGal, while a bulk analysis of eight consecutive scans revealed an average standard deviation of ∼ 8.7µGal indicating systematic effects which drive error above what any individual experiment may suggest. A measurement of a mass inside a cargo container was attempted in order to measure the difference between 421.2 ± 0.3 kilograms of lead being present or not, with an estimated observed gravity of 0.4355 µGal. A difference in observed gravity of 0.51 µGal was measured, which is different from the expected value by less than the resolution of the instrument. The standard deviations of the two measurements were ±1.13µGal for the measurement with mass loaded and ±2.72µGal for the measurement without. While the ability of the Burris ZLS Gravimeter to provide information about close range masses (e.g., spatial distribution, proximity) is thus demonstrated, the extreme sensitivity of the gravimeter stands as a challenge before being field deployable for portal monitorin
Performance of Humans and Agents in a Systems Modeling Language V2 Task: A User-centered evaluation approach
Get PDFThe Department of Defense is adopting Digital Engineering practices for its workforce. Simultaneously, the larger Systems Engineering community strives to modernize and define those Digital Engineering practices. These efforts to move from traditionally document-based approaches to pure digital implementations will require enhanced capabilities to manage and digitally track the lifecycle of a program or product. However, this growth must address tool design through an iterative process focusing on usability for many user types. Many tools and technologies exist but often lack an assessment of usability when engineers design tools for other engineers. Including usability when developing solutions for Digital Engineering tasks may simplify tools and increase further adoption, garnering a larger community of users. This research evaluates twelve participants using Stitch, a custom web-based tool for creating Systems Modeling Language Version 2 (SysMLv2) models and interacting with Virtual Agents. The study uses a mixed-methods approach that combines telemetry metrics and survey responses to evaluate the application’s usability. Through a series of four vignette pairs, Students and Professionals build Systems Modeling Language Version 2 (SysMLv2) models from source documents and investigate model elements. This process balances a traditional file-browser approach and support from Virtual Agents with a pair of visual styles. In this process, the telemetry and survey responses provide insight into the usability of Stitch and the effectiveness of the Virtual Agents. Trends in the study uncover variations in performance and usability within and between both groups. In some cases, Stitch was usable, and the Virtual Agents effectively supported building models. However, the study also found that participants expect additional capabilities and features to support their model-building efforts. This thesis contributes Stitch, built with a user-centered design methodology and evaluated by a use case study as foundational work to understand building SysMLv2 models with support from Virtual Agents. Furthermore, this thesis contributes four pairs of vignettes that guide users through building SysMLv2 models in an instructional fashion. Additionally, two custom model styles and a method for extensibility provide visual queues to aid model interpretation. The vignettes also guide users through interacting with Virtual Agents to access documents while learning to develop SysMLv2 models. Finally, this thesis contributes a set of recommendations for future work to improve the usability of Stitch and other Digital Engineering tools
Disposal and Earth-Moon Escape from Cislunar Orbits using Non-Linear Programming Techniques
Get PDFThis thesis involves theoretical and numerical analysis of trajectories off of cislunar orbits to determine the reachability and escape of various impulsive Δ→v. The research will propagate trajectories using three body dynamics from various orbit families around the Earth-Moon Lagrange points and find low energy transfers that escape the Earth-Moon system. In order to achieve this, various different nonlinear programming solvers in MATLAB will be used to explore low energy impulsive escape transfers from common cislunar orbit families given long periods of computation time. After many points on cislunar orbits are analyzed, the data will be analyzed to spot any trends in Δ→v that could lead to possible guidance for satellite disposal in heliocentric and other possible graveyard orbits for future cislunar missions. The goal is to analyze viability of nonlinear programming solvers in the CR3BP and to see the behavior of impulsive energy transfers and determine possible trajectories for use in Earth-Moon or heliocentric satellite disposal in the cislunar region
Evasion Strategies for Space Engagements with Unknown Pursuer Objectives
Get PDFRealistic simulations provide a tool for operators to understand space tactics and also serve to inform decisions on the requirements of current spacecraft technologies. This research uses simulation to gain a better understanding of one-on-one orbital conflicts through orbital differential games and linear quadratic games. The results of this research find that a simple strategy for an evading spacecraft to successfully evade a more-capable pursuing satellite for a variety of potential goals is to thrust perpendicular to the direction of the pursuer. Specific estimation requirements to accurately determine the objective of the pursuer and successfully evade in a realistic scenario are provided in the document. The methodologies employed in this thesis are applicable to simulate any environment and control law of interest; consequently, these approaches encompass general pursuer-evasion game theory and may be applied in guidance, navigation, and control research more broadly
Toward Adaptive and Modular Joint Multi-Domain Operational Planning
Get PDFThis research develops a multiparametric optimization framework for modeling joint multi-domain operational planning under uncertainty. We address the application of our framework to model the doctrine of adaptive planning. We apply set-based design, which is a program management practice of maintaining maximal design options through time as a response to epistemic uncertainty. We couple this with a multiparametric optimization method yielding both sets of solutions and sensitivity profiles. We use the sensitivity profiles to quantify risk associated with changes during adaptive planning. This research also models features of military operational planning via the mathematics of category theory. We formalize intuitive representations of the doctrinal arrangement of joint operational plans. In particular, we explicitly consider structures naturally present within multi-domain planning and operations—both serial and parallel—in terms of phased operational planning, branches, sequels, and nested planning echelons. We apply models from category theory to provide a formal graphical notation of planning structures under reasonable convexity assumptions
A First Step Towards Understanding Thermomechanical Behavior of the Nb-Cr System through Interatomic Potential Development and Molecular Dynamics Simulations
Get PDFUtilizing a preliminary interatomic potential, this work represents an initial exploration into the thermomechanical behavior of NbCr solid solutions. Specifically, it examines the effect of different amounts of Cr solute, for which information in the literature is limited. The employed interatomic potential was developed according to the embedded atom model (EAM), and was trained on data derived from density functional theory calculations. While the potential demonstrated reasonable accuracy and predictive power when tested, various results highlight deficiencies and encourage further development and training. Mechanical strength, heat capacities, thermal expansion coefficients, and thermal conductivities were found to decrease with Cr content. Elastic coefficients, too, were observed to be strongly dependent on Cr composition. The Pugh embrittlement criterion was not satisfied for any of the compositions and temperatures explored. Gibbs free energy calculations performed on C14, C15, and C36 NbCr2 allotropes predicted the C36 structure to be the most thermodynamically favorable across all investigated temperatures and it was found that C36 becomes increasingly more stable relative to the other two phases with increased pressure. The inability of this work to accurately capture the stability of the different Laves phases is most likely due to the shortcomings in the developed potential
