UMD Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/3
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.
More information is available at Theses and Dissertations at University of Maryland Libraries.
Browse
21 results
Search Results
Item Medford, Oregon | Community Resilience in a Time of Change(2024) Bowers, Jessica Jane; Matthews, Georgeanne; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In recent years, like many places around the globe, Medford, Oregon and the surrounding areas have been severely impacted by events such as the Covid-19 pandemic which caused severe illness and economic hardship for countless families in the region. At the same time, the Almeda Drive and Obenchain fires of 2020 destroyed thousands of homes and left over 4,000 people displaced. The purpose of this thesis is to develop a plan for a revitalized community hub within a greater spatial network based around the Rogue Valley Shopping Center and the Bear Creek Greenway of Medford, Oregon. This place is intended to add another layer of sustainability and support to this community through the creation of programmed public space for finding peace, play, connection, and joy, while also connecting other supportive spaces within the community.Item Three Clostridium species with Health Imparting Properties: In vitro Screening for Probiotic Potential(2024) Mochama, Victor Moronge; Obanda, Diana; Nutrition; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This research aimed to unlock the probiotic potential of the genus Clostridium, which is often overshadowed by the predominant focus on pathogenic species. The study specifically targeted three promising Clostridium species: C. disporicum, C. celatum, and C. vincentii, which have shown potential in mitigating diet-induced obesity. Despite the challenges presented by the anaerobic growth requirements of Clostridium bacteria, the study capitalized on their capacity to sporulate. This characteristic provides an avenue to use them as probiotics, with resilient and dormant spores capable of surviving food processing and harsh stomach conditions. The resilience of these spores was examined by exposing them to oxygen, heat, gastrointestinal juices, and bile salts. The spores survived oxygen exposure, exhibited resilience to both bile salts and gastric acids, and demonstrated a survival temperature of 70°C. When exposed to suitable germination conditions in vitro, the spores successfully germinated. The study assessed the colonization potential of the bacteria by evaluating their adhesion ability, and all bacteria were found to have the adhesion ability. Furthermore, a safety assessment was conducted by examining hemolytic activity and antibiotic susceptibility to selected antibiotics. The bacteria were found to be susceptible to the antibiotics and did not exhibit hemolytic activity. Bile salt hydrolase (BSH) activity and antibacterial activities were also assessed, and none of the bacteria exhibited BSH activity or antibacterial activity. Antioxidant tests revealed that C. vincentii had the highest antioxidant properties. Assessment of anti-inflammatory properties showed that C. celatum downregulated the gene expression of cytokine inflammation markers IL-6, IL-1, and iNOS while upregulating TGF-β expression. In summary all 3 bacterial species showed good probiotic potential from the in vitro tests. Particularly the formation of resistant spores that later germinated to vegetative cells that produced molecular patterns with antioxidant and anti-inflammatory properties. This necessitates further studies on their probiotic properties.Item BREAKWATER – Breaking the Cycle(2024) Mora, Adrian Bernard Teneza; Gabrielli, Julie; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)How can ecological design principles prevent the erosion of the physical and social framework of low-income coastal communities? A significant portion of the world’s population is concentrated along coastlines. Direct access to the water provides access to a longstanding source of economic prosperity and a psychological connection to natural environments. However, human-influenced climate change has produced hazardous environmental conditions that threaten coastal populations, including many poor, vulnerable communities. Disparities in investment for public services, maintenance, and upkeep increases the vulnerability of these disenfranchised groups that cannot protect themselves. The built and natural environment within this diverse boundary zone between the land and sea must be redeveloped as a self-resilient ecosystem that can protect its inhabitants from climate-induced hazards. This renewal will require holistic approaches that can mitigate contemporary impacts to protect current populations at risk and adapt the built environment to better respond in the future.Item Persisting Social Vulnerability, Stormwater Infrastructure, and Planning for Flooding and Resilience in Washington D.C.(2024) Park, Minkyu; Hendricks, Marccus D; Urban Studies and Planning; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)While Green Infrastructure (GI) has gained prominence in addressing climate change, particularly in flood prevention and other associated benefits. Limited empirical studies have explored its spatial distribution and temporal changes in relation to the whole stormwater infrastructure. This dissertation investigates the intersection of stormwater infrastructure, social vulnerability, and urban flood management strategies in Washington, D.C. The dissertation is composed of three studies. The first study employs geospatial exploration to assess the equitable allocation of stormwater infrastructure, considering historical discriminatory sewage services. Regression models reveal significant disparities in stormwater infrastructure distribution among communities with varying levels of social vulnerability, highlighting the inequitable distribution within urban areas. The study contributes valuable insights for stormwater management planning in the context of climate-related challenges.The second quantitative study focuses on the spatial and temporal evolution of GI distribution in Washington, D.C., utilizing spatial panel data analysis. Unlike previous cross-sectional snapshots, this study captures temporal trends in GI distribution in relation to social vulnerability. The findings, with potential implications for evidence-based policies, shed light on the evolving patterns of discriminatory distribution of GI and its relation to persistent social vulnerability. The third study employs an Environmental Justice (EJ) framework to critically analyze the urban flood management initiatives in Washington, D.C., specifically examining the Flood Task Force (FTF) action plan. The study uncovers limitations and potential exacerbations of place vulnerabilities within current plans through qualitative coding. This research contributes to the ongoing discourse on achieving more equitable and resilient urban flood management in the city, emphasizing the need for environmental justice considerations. The thorough examination of stormwater infrastructure, social vulnerability, and the initiatives of the DC Flood Task Force uncovers a tripartite phenomenon: 1) uneven distribution of stormwater infrastructure is influenced by social vulnerability, 2) temporally widening the gap in infrastructure among communities, and 3) overlooking social vulnerability and the unfair allocation of stormwater infrastructure in planning or policies could intensify place vulnerability.Item SATELLITE SERVICING AS A MEANS TO INCREASE SPACE MISSION RESILIENCE IN LOW EARTH ORBIT: A PARAMETRIC ARCHITECTURE ANALYSIS(2023) Gabriel, Jonathon Loegan; Akin, David L; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Satellite servicing and associated capabilities have the potential to establish a new space mission design and operation paradigm throughout Earth orbit. By integrating fundamental elements of the logistics chains that complex engineered systems enjoy on Earth’s surface to Earth’s orbit, the feasible domain for space missions will significantly expand. Some estimates suggest that the burgeoning satellite servicing industry could generate over 14 billion United States Dollars in revenue over the next decade, driven in large part by growing demand from satellite operators in Low Earth Orbit. However, despite significant economic development and the modern shift of commercial and government space industry focus to Low Earth Orbit, the study of satellite servicing architecture design in this context requires more analysis to mature. Existing satellite servicing mission design literature generally investigates the system design problem as an economic feasibility analysis or system optimization problem. A subpopulation of this literature introduces novel design metrics to the system design process, such as mission flexibility, bringing significant utility to mission designers. In recent years, mission resilience has proven to be a space mission design metric of significant interest to a diverse set of stakeholders such as the United States Department of Defense. Despite its rapidly expanding use, resilience in the context of space mission design has been described primarily qualitatively, limiting its engineering use. Satellite servicing, as with other applications of engineering resilience techniques, aims to integrate capabilities into a complex system that enables a response to system degradation in a favorable manner. This thesis develops a robust simulation framework to parametrically investigate the Low Earth Orbit satellite servicing system design space in the context of scenarios of interest, such as the potentially degrading events of solar storms, orbital debris collisions, and natural satellite failures. A focus will be placed on quantifying the effects on system resilience that satellite servicing can afford Low Earth Orbit constellations. First-order space mission design parameters will be parametrically investigated using the developed analysis and simulation framework. Through leveraging the Earth’s J2 perturbation to help route servicer satellites efficiently throughout a constellation of modeled customer satellites, it will be shown that the integration of satellite servicing capabilities into Low Earth Orbit constellations can significantly increase system resilience inside the performance constraints of existing space vehicles. Satellite Servicing system design strategies will be presented that can be employed to increase mission resilience and feasibility.Item Affective Reactions to Uncertainty as Driven by Past Experiences, Personality, and Perceived Valence(2022) Ellenberg, Molly Deborah; Kruglanski, Arie; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The assumption that uncertainty is inherently threatening which underlies decades of research belies the fact that people rarely react negatively to uncertain situations about which they do not care, and that some are excited by uncertainty. I propose that affective reactions to uncertainty are driven not by uncertainty itself, but by people’s expectations of positive and negative outcomes to personally relevant uncertain situations. I find that positive past experiences predict higher optimism and higher resilience, both of which predict higher tolerance of uncertainty and more positive perceptions of uncertain events. I also find that negative past experiences predict higher pessimism and lower resilience, both of which predict higher intolerance of uncertainty and more negative perceptions of uncertain events. The second study suggests that optimistic people are more likely to approach, rather than avoid, uncertainty. The third study finds that mindfulness training, which emphasizes non-attachment to outcomes, results in more neutral reactions to uncertainty. Theoretical and practical implications are discussed.Item The Resilient Island - Revitalizing a Broken Home(2022) Peña, Alexander Bradley; Hu, Ming; Tilghman, James; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Disaster struck Puerto Rico on September 6th, 2017, when Hurricane Irma, a category 5 hurricane, breached the islands. Communities had no time to recover as Hurricane Maria, an even bigger threat, reached land not more than two weeks later. These two disasters happening in quick succession led to a devastating death toll of 2,975 people and caused a total of $90 billion in damages. This had been the most devastating disaster to hit in over 100 years. The people of Puerto Rico are still recovering to this day and are trying to find solutions to creating community resiliency. This thesis will focus primarily on what makes a community resilient and how to apply this to other Caribbean nations. Not all Caribbean islands face the same challenges and each one has its own identity. To assume that all islands are the same would be irrational. Additionally, this thesis will look at how a community can shift from being unconventional to very functional. Throughout the recent years, there has been a shift in design and function toward creating communities that are more sustainable, durable, and resilient. While this shift can occur easily in more modern societies, those that lack the resources to do so will continue to struggle unless proper support can be given.Item Enhancing Ellicott City: Introducing Resiliency to a Damaged Community(2022) Toth, Austin Robert; Kelly, Brian; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The historic Main Street area of Ellicott City has suffered massive hardships over the last several years, with two devastating floods causing considerable damage to the vibrant small business community. The county has already begun implementing their flood mitigation development plan which features a tunnel system to divert water from Main Street. While this solves some of the flooding issues, a redesign of the area is crucial to the restoration of the once prosperous community. With small businesses struggling, bringing more people into Ellicott City is important for its vitality. Currently, Main Street is seen as a destination, rather than a living space, even though it contains many of the amenities needed to foster a commercially vibrant and resilient neighborhood. Through tactical urbanism, there are many opportunities to infuse the city with new community spaces, higher density housing, and sustainable interventions, with the goal of creating an economically resilient community.Item ENHANCING RESILIENCE OF COMPLEX NETWORKS: WASHINGTON D.C. URBAN RAIL TRANSIT AS A CASE STUDY(2020) Saadat, Yalda; Ayyub, Bilal BA; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)According to the United Nation’s Department of Economic and Social Affairs Population Division, 66% of the world’s population will reside in urban areas by 2050; a boost from 30 % in 1950. Urbanization has indeed triumphed and its speed has brought innovation and economic growth. Its synergies within infrastructure systems are undeniable and have increased the demand for such systems. However, urbanization is one reason infrastructure systems are knocked out of equilibrium and show complex dynamical behavior. Most infrastructure systems have been designed without planning for this magnitude of potential demographic changes; thus redesigns are long overdue. Also, climate change looms. Resource scarcity and host of other factors leave their impacts; all pose some incidence of perturbation in the state of the infrastructure system. These perturbations can affect the system’s resilience, which is a defining property of each system for remaining functional in the midst of disruption from an adverse event. Therefore, it is essential to develop appropriate metrics and methods to enhance the resilience of infrastructures at the network level. Such enhancements are critical for sustainable infrastructure development that is capable of performing satisfactorily through intentional and/or stochastic disruptions. A resilience evaluation of a network typically entails assessing vulnerability and robustness as well as identifying strategies to increasing network efficiency and performance and offering recovery strategies ideally taken in a cost-effective manner. This dissertation uses complex network theory (CNT) as the theoretic basis to enhance the resilience of large-scale infrastructure networks, such as urban rail transit systems. Urban rail transit infrastructures are heterogeneous, complex systems consisting of a large number of interacting nodes and links, which can imitate a network paradigm. Any adverse event leading to a disruption in the interaction and connectivity of network components would dramatically affect the safety and wellbeing of commuters, as well as the direct and indirect costs associated with performance loss. Therefore, enhancing their resilience is necessary. Using the Washington D.C. Urban rail transit as a case study, this dissertation develops a methodology to analyze network topology, compute its efficiency, vulnerability, and robustness in addition to provide a unified metric for assessing the network resilience. The steps of methodology are applied to two models of weighted and unweighted networks. For the weighted model two novel algorithms are proposed to capture the general pattern of ridership in the network, and to reflect the weights on assessing network efficiency, respectively. This dissertation then proposes an effective strategy to increase the network resilience prior to a disruptive event, e.g., a natural disaster, by adding several loop lines in the network for topological enhancement. As such, adding a loop line can create redundancy to the vulnerable components and improve network resilience. Expanding on this, the dissertation offers comparative recovery strategies and cost model in the case of disruption. An effective recovery strategy must demonstrate rapid optimal restoration of a disrupted system performance while minimizing recovery costs. In summary, the systematic methodology described above, assesses and enhances the network resilience. The initial results rank the most vulnerable and robust components of the network. The algorithms developed throughout the study advance the weighted network analysis state of art. The topological enhancement strategy offered basis to justify capital improvement. Post failure recovery analysis and the cost model serves to inform decision makers in identifying best recover strategies with special attention not only to restoring performance of a system but also on reducing associated failure and recovery costs. The use of the methodology proposed in this dissertation may lead to significant societal benefits by reducing the risk of catastrophic failures, providing references for mitigation of disruption due to adverse events, and offering resilience- based strategies, and related pursuits.Item GREEN INFRASTRUCTURE IN INTEGRATED URBAN WATER MANAGEMENT: MODELING AND SOCIAL-ECOLOGICAL SYSTEM APPROACHES(2020) Mosleh, Leila; Pavao-Zuckerman, Mitchell Adam; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urbanization, climate change, increasing water demand, deteriorating water quality, and insufficiencies in system resilience have encouraged city planners to consider integrated urban water management (IUWM) as a solution. One of the main benefits of IUWM is looking into stormwater as a resource to decrease the need for potable water and put less burden on wastewater treatment systems and the environment. Green infrastructure (GI) is an essential part of stormwater management that is designed to mimic the natural hydrological cycle and allows for infiltration, capture and reuse, and treatment of stormwater. This dissertation is designed to inform urban water decision-makers with a special focus on GI via assessment and management frameworks and stakeholder engagement. In my first study, I provided a comparative study of IUWM models aimed at assisting users to select the most appropriate model according to any specific needs. Our results showed that most of IUWM models included stormwater management and GI selection, but do not consider ecosystem services evaluation and the supply and demand from GI. Following these deficiencies of the available models, in my second study, I looked into the stakeholders’ knowledge, perception, and practice of GI with respect to ecosystem services supply and demand. The results showed the study of supply and demand, as well as ecosystem disservices, can help the selection of effective forms of GI to address the priority of stakeholders and environmental issues. Selection of the right type of GI is important for the sustainability of GI in providing ecosystem services, but so is monitoring and evaluation of GI. Thus, my third study focused on developing a generalized social-ecological framework for assessing urban stormwater GI resilience. The results of this study showed that assessing resilience requires linking indicators to critical functionality of GI, as well as a social-ecological approach that goes beyond design and technical specifications. This study can help prioritize resources to address goals related to building resilience. In my last study, I aimed to refine and co-produce a specific social-ecological framework for stormwater GI resilience with stakeholders that links to perceived barriers and challenges of implementing GI. Stakeholders co-created indicators considering current GI challenges and linked them with resilience management dimensions. This framework could inform the management of adverse events and improve resilience by decision-makers and multi-stakeholders in various sectors related to GI planning, design, and implementation.
- «
- 1 (current)
- 2
- 3
- »