RSS 1.0ScholarWorks@UA
ScholarWorks@UA is University of Alaska's institutional repository created to share research and works by UA faculty, students, and staff
Communities in Scholarworks@UA
Select a community to browse its collections.
Recently Added
-
The STEM trail: Alaska Native undergraduates find the right path in higher educationThe goals of this research are twofold. (1) This research explores decision making and college experiences of Alaska Native undergraduates pursuing degrees in the science, technology, engineering, and mathematics (STEM) fields, and (2) this research, using participant observation explores the Indigenous metaphor of "the trail" to frame student persistence towards their degrees. Twelve participants, representing various STEM fields, Alaska Native cultures, and K12 schooling experiences, shared their motivations and aspirations through interviews and photographs. Key findings indicate the significant role that Indigenous Knowledge plays in influencing student decisions around majoring in STEM degrees. Findings also illuminate the variety of K12 STEM experiences and the influence on decisions to major in STEM. Awareness (ellangeq) and self-authorship as student development theory, also impact decision making. The use of "the trail" as a metaphor for persistence illustrates a strength-based model for persistence, that notes the importance of the individual and the role of the individual as a community member. This metaphor also displays aspects of preparation, finding the right path, obstacles, supports, and destinations. This metaphor also calls into question the role of the institution as students work to navigate the terrain towards their degrees.
-
Optimization and forecasting algorithms for converter dominated distribution networks using blockchain and AIIntegration of power electronic converter-based distributed energy resources (DERs) in electric power distribution networks is growing exponentially with the recent interest in reducing carbon emissions from fossil fuel-based generation. As the contribution of renewable energy sources in the DER mix continues to increase, so does the incorporation of battery energy storage systems and other controllable loads to compensate for the high variability and uncertainty in the generation from renewable DERs and grid demand. Strategies for increasing the contribution of renewable energy sources and using reserves to accommodate for variations and uncertainty in generation and load include distributed optimal power flow (OPF) methods and improved forecasting. This work proposes a co-optimization of power flow and flexibility reserves, executed on a private blockchain for security, solved using a parameterized deterministic method based on semi-distributed architecture and alternating direction method of multipliers (ADMM) based distributed architecture that addresses uncertainty and enhances the flexibility of the distribution network. However, ADMM guarantees convergence only for strictly convex problems and hence a relax-and-fix heuristic algorithm is proposed in co-ordination with ADMM to solve the OPF problem, which is non-convex in nature. Also, an accurate short-term load forecasting algorithm is essential to reduce the uncertainty in the dispatch results using the OPF algorithm. In this work, a short-term residential load forecasting algorithm is proposed using a two-stage stacked long short-term memory network-based recurrent neural network and Hampel filter to address this issue. All the proposed algorithms are tested using different case studies. Results demonstrate that the proposed algorithms reduce the impact of uncertainty in the distribution network, automate scheduling flexibility reserve and minimize its cost, reduce the OPF execution time using a distributed architecture, and produce residential load forecast with a significantly lower prediction error.
-
Marine debris in the Bering Sea: combining historical records, toxicology, and local knowledge to assess impacts and identify solutionsMarine debris, particularly plastic marine debris, has numerous impacts on the environment, wildlife, and human communities. This research examines dimensions of marine debris in the Bering Sea and Aleutian Islands, Alaska, including impacts of marine debris pollution on wildlife and the environment; the history of marine debris research, monitoring, and cleanup activities; and community perspectives on local to global solutions. The first chapter of this dissertation is an integrative literature review to better understand the current status of marine debris knowledge in the Bering Sea region and identify critical knowledge gaps. We synthesized the depth and breadth of research, monitoring, and cleanup activities to better understand the sources, prevalence, and impacts of marine debris on wildlife and coastal communities. Our review revealed several knowledge gaps, including two that were a focus of the final chapters of the dissertation: measuring the extent of plastic-associated contaminants in the Bering Sea and capturing community perspectives and concerns about marine debris in the Bering Sea. The second chapter examined variation in phthalates, a class of plastic-associated chemicals, in Aleutian Islands seabirds, to refine hypotheses regarding ecological and environmental factors that affect phthalate exposure in marine wildlife. We quantified phthalates in seabirds collected across >1700 km of the Aleutian Islands, Alaska, and measured six phthalate congeners in seabirds representing ten species and four feeding guilds. Phthalates were detected in 100% of specimens (n = 115) but varied among individuals (range 3.64 - 539.64 ng/g). Total phthalates did not vary geographically, but differed among feeding guilds, with significantly higher concentrations in diving plankton-feeders compared to others. Our findings suggest feeding behavior could influence exposure risk for seabirds and lend further evidence to the ubiquity of plastic pollutants in marine ecosystems. The final chapter of the dissertation explored perspectives and concerns of St. Paul Island community members regarding marine debris and plastic pollution. This component of the research aimed to catalyze the inclusion of local knowledge in marine debris solutions for St. Paul Island, Alaska, by documenting community members' perceptions of marine debris, including its origin, impacts, and proposed solutions. We interviewed thirty-six St. Paul Island community members from 2017 to 2020 about the types, amount, distribution, and impacts of marine debris they have observed on the island and its surrounding waters over recent decades. Research participants reported increases in plastic debris since the 1980s, particularly plastic bottles. Nearly 80% expressed concern about impacts to subsistence resources, including entanglement and ingestion of plastic particles by marine mammals and fishes. St. Paul Island community members' experiences highlight that solving the problem of marine debris cannot rely on local efforts alone but requires broader policies and mitigation strategies to address the sources of debris and advance environmental justice for coastal communities. Overall, this dissertation contributes an improved understanding of the social and ecological impacts of plastic pollution in the Bering Sea region and the potential science and policy solutions that can stem the tide of marine debris.
-
Seeing the forest through the trees: how site conditions mediate white and black spruce responses to climate in Interior AlaskaThe boreal forest provides essential ecosystem services and helps regulate global climate. With climate change occurring at a faster rate at high latitudes, including in the boreal forest biome, it is critical to understand how boreal forests are responding to these unprecedented changes. Despite much effort, uncertainty remains as to how boreal forest productivity has and will change with ongoing climate changes. Some of the uncertainty reflects the complex mosaic of regional climatic patterns, direct and indirect species-specific responses to regional climate, and heterogenous local site conditions that affect boreal forest productivity. I focused on the latter uncertainty: the potential role of topographic, edaphic, and biotic conditions in mediating the climate-growth responses of boreal tree species. My overarching goal was to quantify the radial growth response of black spruce (Picea mariana) and white spruce (Picea glauca), the two most common tree species in interior Alaska, to climate variability across a suite of site conditions to better understand the observed and predicted variation in climate driven productivity across a variable landscape. I employed a systematic sampling design to quantify the landscape-scale patterns in both environmental conditions and incremental annual growth of trees distributed across a 1.28 million-ha study area in Denali National Park and Preserve (and beyond in Chapter 4). I also used targeted sampling of carbon isotopes in tree rings to investigate potential drought stress. I found that near-surface permafrost, slope angle, and elevation strongly modified the magnitude, shape, and, in some cases, the direction of radial growth response of both species. For white spruce, the negative growth response to warm and dry summer conditions intensified in high competition stands and in areas receiving high potential solar radiation. During years with high cone and seed production, white spruce shifted its current year's carbon resources from radial growth to reproduction and showed signs of drought stress. I also observed differences between black and white spruce climate-growth responses, with near-surface permafrost driving their contrasting responses to June-July temperatures and with black spruce growth showing an overall more positive response to summer precipitation. These results demonstrate that local site and stand variables can force contrasting growth responses to similar climate conditions and help predict how future black and white spruce growth may play out with climate changes across a heterogeneous landscape. My results underscore the pivotal role of near surface permafrost in both the climate-growth responses and competitive dynamics of black and white spruce. Consequently, my results emphasize the importance of ongoing and predicted changes in the distribution and prevalence of permafrost for the future of the boreal forest.
-
The linguistic dreamstate: Freud, Lacan, and intertextuality in Samuel Beckett's The UnnamableThis thesis focuses on the process of symbolization and signification in Samuel Beckett's novel, The Unnamable. The introduction presents readers with important and relevant critical interpretations of the novel, primarily those that are focused on the self, the use of language, and psychoanalytic theory. Then, the thesis introduces readers to key concepts in semiotic and psychoanalytic criticism, such as that of the signifier, sign, big-O Other, and the Lacanian Imaginary, Symbolic, and Real, by applying these concepts to a reading of The Unnamable. The next section, "The Linguistic Dreamstate," argues that the novel's narrator occupies a state tangential to consciousness, subconsciousness, and unconsciousness. In occupying this state, one that is outside of physical reality, the narrator is confronted with a language he does not understand and, while speaking, seeks to understand what he has previously said, mirroring the process of psychoanalysis as it concerns the meaning of dreams. Finally, it is shown that the narrator attempts to use language to as a means to stop using language. In so doing, the narrator illustrates the inability of language (and the Symbolic) to reconstruct the Real, and the innate desire for the Real (or objet a) even in those who do not have a reality within which they see the lack of the Real.
