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Deep Learning Approach for Accurate Segmentation of Oil Spills in Marine Systems
Get PDFOil spills present critical environmental hazards, threatening marine ecosystems and necessitating fast, accurate detection for effective mitigation. Synthetic Aperture Radar (SAR) imagery has been instrumental in detecting oil spills, but manual interpretation is often inefficient and prone to errors. This study addresses the limitations of manual methods by proposing a deep learning approach for automated oil spill detection and segmentation.
Utilizing a novel transfer learning-based semantic segmentation model, this research focuses on detecting oil slicks on the sea surface with higher accuracy and efficiency. The model leverages pre-trained networks and incorporates U-Net variants, including UNet++ and MultiResUNet, to optimize spatial and contextual information extraction across different scales. These modifications enable the system to accurately detect oil spills of varying shapes and sizes while reducing the need for large datasets.
Trained on a dataset that includes National Oceanic and Atmospheric Administration (NOAA) imagery and augmented samples, the model demonstrates superior performance in segmentation accuracy. The proposed solution integrates cutting-edge techniques like attention gates and multi-resolution convolution blocks, leading to faster processing and more reliable detection. The findings suggest that applying advanced deep learning methods significantly enhances oil spill monitoring systems, offering a powerful tool for real-time environmental protection and response efforts
The Last Duel? Kulturkämpfe in fin de siècle New Orleans
Get PDFAn 1897 murder in New Orleans’ French Quarter appeared to be a commonplace barroom-brawl-gone-bad. However, a historical analysis of the crime reveals the complex intersection of race, ethnic identity, and a new meaning of manhood at the turn of the century. When we place the words exchanged between the two men inside urban spaces and the Atlantic world of the late nineteenth century, how racial and gender formation unfolded on the street becomes clear. This microhistory applies spatial analysis and a deep read of newspapers, magazines, and court documents. It addresses a topic not yet fully explored, namely, the intersection of Creole and French identity with a new ideal of manhood. It is the story of a Kulturkampf—a culture war-- and of the long-standing tradition in the United States to resort to extra-legal violence to settle disputes
An Integrated Transformational Teaching Model for Empowering Undergraduate Psychology Students to Cultivate Self-Awareness, Wellness Practices, and Resilient Mindsets during their Undergraduate Careers
Get PDFThis Narrative inquiry explored psychology students’ perceptions of self-awareness interventions and wellness training in undergraduate psychology coursework. Participants included seven undergraduate psychology majors who completed a psychology health and wellness course in the Fall 2023 semester at a regional university in the Southeast. Semi-structured interviews were conducted and examined to identify themes in the students’ stories regarding their journeys through the wellness course. The use of reflexive thematic analysis helped determine the following five overarching themes from the data: Roadmap for Navigating Wellness, Group Experience, Newfound Insight, Personal Growth and Transformations, and Moving Forward. The results of this study highlighted the importance of self-awareness and wellness in aspiring Mental Health Practitioners
Family Conflict & Children\u27s Problem Behaviors: A Bidirectional Analysis Across Emerging Adolescence
Get PDFResearch has shown that living in a family high in negative and hostile conflict is detrimental to children’s adjustment. As youth transition into adolescence, their desire for more autonomy can lead to changes in the family dynamic, such as increased family conflict. What is lesser known are the ways in which families may differ in how conflict changes during this time, how these differences may influence adjustment, and whether having a child with problem behaviors may lead to increases in family conflict.
The present studies used four waves of data from the Adolescent Brain & Cognitive Development study, an ongoing longitudinal study of 11,868 nine to ten year old youth and their parents. At all four waves, parents and youth independently reported on levels of family conflict (Family Environment Scale-Conflict subscale; Moos & Moos, 1974). Parents reported annually on youths’ internalizing and externalizing behaviors (Child Behavior Checklist; Achenbach & Rescorla, 2000).
Parents reported family conflict as low and decreasing over four years, whereas youth reported low initial levels which increased over four years. Significant variance in growth parameters suggested variation around starting points and rates of change over time. Latent growth class analyses uncovered four latent patterns of family conflict for each reporter, each with a majority group which started out low and stayed low over four years. These patterns predicted both later internalizing and externalizing behaviors, with the majority low classes showing the least problem behaviors.
Youth-reported family conflict was bidirectionally associated with externalizing behavior, in that families with greater than expected conflict had children with more externalizing behaviors, and youth with more externalizing behaviors reported greater than expected conflict at home. Internalizing behavior, however, did not predict later family conflict, though family conflict predicted deviations in later internalizing behavior. Parent-reported conflict and youths’ problem behaviors were neither unidirectionally nor bidirectionally predictive.
These findings add to the literature by showing that externalizing behaviors are both predictive of and predicted by family conflict, whereas internalizing behaviors are not. At the same time, the existence of more than one pattern of family conflict suggests that, while slow changes in conflict may be occurring across the larger population, there exist unique patterns of family functioning which can better predict youths’ maladjustment
Towing Tank Trials of Hydrokinetic Turbine Scale Model to Support Marine Energy System Verification
Get PDFIn response to the escalating demand for sustainable energy solutions and the critical reevaluation of conventional fossil fuels due to environmental concerns, this dissertation embarks on a comprehensive exploration of hydrokinetic energy as a promising alternative. The study delves into the underexplored domain of hydrokinetic energy, leveraging innovative methodologies for effective utilization and harnessing, particularly through the development and investigation of hydrokinetic turbines.
In the realm of hydrokinetic energy conversion, our research has exclusively concentrated on horizontal-axis turbines, distinct from other turbine configurations. Noteworthy is the adaptation of a conventional horizontal-axis wind turbine for water currents, revealing enhanced performance through experimental and computational methodologies, emphasizing the unique properties of water and insights gained from computational fluid dynamics (CFD) analysis.
Parallel to the developmental trajectory of wind turbines, the dissertation emphasizes the need for empirical validation through systematic experimentation to understand and optimize the behavior of hydrokinetic turbines. A novel testing approach, utilizing towing tanks commonly employed in maritime engineering, is introduced. This approach, focused on the conversion of ocean currents\u27 kinetic energy, parallels the testing methodologies used for wind turbines, highlighting the commonality with horizontal-axis turbines. Specialized numerical methods, validated through a simulation tool based on Blade Element Momentum (BEM) theory, enhance confidence in the applicability of these methods for marine current turbine development.
The groundbreaking methodology for dynamometer testing of hydrokinetic turbines is a central focus of the research. Utilizing towing tanks as a testing platform, this approach involves a minimized hydrokinetic turbine model enclosed within a 3D-printed watertight nacelle. Integrated sensors capture crucial parameters, enabling comprehensive data collection for energy consumption, torque, and power generation. This methodology presents a promising avenue for advancing the development of hydrokinetic turbines, aiming for standardized and verifiable procedures for testing and experimentation.
The study extends its reach to the potential market opportunities derived from harnessing hydrokinetic energy, drawing parallels between hydrokinetic turbines and wind turbines. The dissertation outlines a systematic testing and development approach inspired by well-established methods in the wind energy sector, aligning with the guidelines of the International Towing Tank Conference (ITTC). The proposed methodology, organized into several chapters, covers aspects such as adaptation of towing tanks, selection of scale models, instrumentation and sensors, dry dynamometer characterization, nacelle design, testing procedures, and redesign with magnetic coupling.
In essence, this dissertation seeks to revolutionize underwater turbine testing by integrating principles from naval architecture and adapting them to the unique challenges of hydrokinetic energy. The proposed methodology ensures robustness, repeatability, and valuable insights into the hydrodynamic performance of hydrokinetic turbines, contributing significantly to the advancement of ocean current energy conversion technologies
The PAWN System: How Procedurally Adaptive Webbed Narratives Create Stories
Get PDFThis thesis describes the design, implementation, and testing of a novel procedural narrative system called the Procedurally Adaptive Webbed Narrative (PAWN) system. PAWN procedurally generates characters and, responding to choices made by the player, produces more responsive characters and relationships involving the player and these narrative agents. Initially, this thesis discusses other interactive narrative types that exist, such as emergent or event-driven narratives, along with their strengths and weaknesses. It then examines each aspect of PAWN, starting with initial actor generation, then moving to the capturing of game events and translating them into logical objects called Occurrences. These Occurrences are then parsed into Predicates, which are more character-focused relational objects. These Predicates are continually queried for specific Narrative Patterns, and, if found, introduce more specific and interesting Predicates into the PAWN’s current Predicate list. Furthermore, the dialogue selection and tailoring process derived from the most interesting of these Predicates is explained. Conducting A/B tests with PAWN and the control narrative system (NONPAWN) in the same game base revealed unanimous user preference for PAWN, with users judging PAWN characters to be more responsive and interesting than their NONPAWN alternatives
Investigation on the Effects of Biofouling on the Boundary Layer
Get PDFThis study is an investigation of the effect of biofouling on the boundary layer of a flat plate and a NACA 4-digit series foil. Three identical hydrofoils made of resin were placed in the Gulf of Mexico at Grand Isle, Louisiana, and observed and analyzed by marine biologists at the University of New Orleans for their species composition. The resulting biofouling that grew was primarily made up of barnacles and bryozoans. The foils were submerged in an open channel flume at zero incidence and subjected to a series of experiments whose arc-length Reynolds numbers ranged from approximately 13000 to 32000. The flow regime around the fouled foils was laminar and captured in a series of experiments using two-dimensional particle image velocimetry. The resulting data was compared to the flow regime around an identical foil with no biofouling on its surface, which was tested using the same methods at zero incidence. The flow regime of the “clean foil” was also captured using two-dimensional particle image velocimetry. The effects of the biofouling on shear stress, boundary layer thickness, and velocity profiles were analyzed. The strengths and weaknesses of using the particle image velocimetry method for capturing flow around biofouling was also discussed. Two dimensional simulations of the fouled foils were created in the commercial computational fluid dynamics software ANSYS Fluent for comparison to the results of the particle image velocimetry experiments on the fouled foils. The experiments on the fouled foils found that the biofouling causes the boundary layer thickness to increase along the length of the foil in comparison to the boundary layer of the clean foil. However, at these Reynolds numbers, even relatively large and obstructive biofouling such as barnacles do not cause significant disruption of the boundary layer or the flow regime. The two-dimensional simulations of the fouled foils compare favorably to the corresponding experimental results, although they slightly overpredict the effect the biofouling has on the separation regions of the fouled foil, which are located downstream of the location of maximum thickness. For example, the separation regions, and therefore the boundary layers, were somewhat thicker in the simulations than in the experiments. It was found that upstream of the location of maximum thickness of the foil, the simulations and experiments showed better agreement in terms of thickness of the boundary layer and the nature of the velocity profiles. It was determined that particle image velocimetry is effective and recording velocity profiles of biofouled surfaces along with shear stress data. Further studies should investigate other types of fouling and whether three-dimensional computational fluid dynamics simulations would be more effective for this purpose, and worth the additional computational cost.
Keywords: boundary layer, biofouling, computational fluid dynamics, hydrofoi
Analysis of Grid Forming Inverter (GFM) and Grid Following Inverter (GFL) Models In Simulating Power Systems With Varying Short Circuit Ratio (SCR)
Get PDFThe primary objective of this study is to assess the weaknesses and susceptibilities of the power grid before the inverter-based resources (IBR). The weak spots within the grid, specifically at the point-of-interconnection (POI) for photovoltaic (PV) systems, are identified by using a classic short circuit ratio (SCR) metric. The performance of grid-following (GFL) and grid-forming (GFM) inverter types is compared using a 100 MVA-rated PV facility that is connected to a transmission line network. By subjecting the system to a six-cycle three-phase to ground fault at different sites, such as the PV POI and nearby busses, SCR values of roughly 4.5, 3, and 1.5 are recorded, respectively. The analysis shows that when the SCR at the PV POI is low, the GFM inverter has faster and smoother fault recovery responses in terms of active and reactive power compared to the GFL inverter