Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

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 give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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    Of Land and Spirit: Reciprocity and Ritual in Land Stewardship
    (2022) Haider, Almas; Williams, Brittany; Architecture; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    Across the U.S., queer and trans Black, Indigenous, and people of color are choosing to live communally in sub-rural landscapes. In doing so they are divesting from limiting socio-political and economic structures and modeling a liberatory existence, not limited to surviving the present but intending to thrive generations to come. This thesis builds on their vision and considers how to design residential and retreat spaces rooted in an interdependence with the land and other species. It considers human-non-human entanglements as a key to living in right relationship to the lands we occupy and understanding our sacred roles as land stewards. And further invites the sacred into our dwellings, imbibing ritual, cosmology, and symbolism into our daily lives that keeps us thriving. It uses the precedents of maroons and community land trusts as models of land stewardship that co-created futures in symbiotic relationships with the land and other species. And offers a thoughtful design tailored for an existing Afro-Indigenous land stewardship in the Blue Ridge mountains of Appalachia to be in reciprocity with plant, animal, and mineral species. The design will focus on the adaptive reuse of two barns on the site, new emergent structures, and new housing.
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    Cyclic Pursuit: Symmetry, Reduction and Nonlinear Dynamics
    (2011) Galloway, Kevin; Krishnaprasad, Perinkulam S; Justh, Eric W; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In this dissertation, we explore the use of pursuit interactions as a building block for collective behavior, primarily in the context of constant bearing (CB) cyclic pursuit. Pursuit phenomena are observed throughout the natural environment and also play an important role in technological contexts, such as missile-aircraft encounters and interactions between unmanned vehicles. While pursuit is typically regarded as adversarial, we demonstrate that pursuit interactions within a cyclic pursuit framework give rise to seemingly coordinated group maneuvers. We model a system of agents (e.g. birds, vehicles) as particles tracing out curves in the plane, and illustrate reduction to the shape space of relative positions and velocities. Introducing the CB pursuit strategy and associated pursuit law, we consider the case for which agent i pursues agent i+1 (modulo n) with the CB pursuit law. After deriving closed-loop cyclic pursuit dynamics, we demonstrate asymptotic convergence to an invariant submanifold (corresponding to each agent attaining the CB pursuit strategy), and proceed by analysis of the reduced dynamics restricted to the submanifold. For the general setting, we derive existence conditions for relative equilibria (circling and rectilinear) as well as for system trajectories which preserve the shape of the collective (up to similarity), which we refer to as pure shape equilibria. For two illustrative low-dimensional cases, we provide a more comprehensive analysis, deriving explicit trajectory solutions for the two-particle "mutual pursuit" case, and detailing the stability properties of three-particle relative equilibria and pure shape equilibria. For the three-particle case, we show that a particular choice of CB pursuit parameters gives rise to remarkable almost-periodic trajectories in the physical space. We also extend our study to consider CB pursuit in three dimensions, deriving a feedback law for executing the CB pursuit strategy, and providing a detailed analysis of the two-particle mutual pursuit case. We complete the work by considering evasive strategies to counter the motion camouflage (MC) pursuit law. After demonstrating that a stochastically steering evader is unable to thwart the MC pursuit strategy, we propose a (deterministic) feedback law for the evader and demonstrate the existence of circling equilibria for the closed-loop pursuer-evader dynamics.