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.
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Item HIGH PERFORMANCE AGENT-BASED MODELS WITH REAL-TIME IN SITU VISUALIZATION OF INFLAMMATORY AND HEALING RESPONSES IN INJURED VOCAL FOLDS(2019) Seekhao, Nuttiiya; JaJa, Joseph; Li-Jessen, Nicole Y. K.; Electrical Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The introduction of clusters of multi-core and many-core processors has played a major role in recent advances in tackling a wide range of new challenging applications and in enabling new frontiers in BigData. However, as the computing power increases, the programming complexity to take optimal advantage of the machine's resources has significantly increased. High-performance computing (HPC) techniques are crucial in realizing the full potential of parallel computing. This research is an interdisciplinary effort focusing on two major directions. The first involves the introduction of HPC techniques to substantially improve the performance of complex biological agent-based models (ABM) simulations, more specifically simulations that are related to the inflammatory and healing responses of vocal folds at the physiological scale in mammals. The second direction involves improvements and extensions of the existing state-of-the-art vocal fold repair models. These improvements and extensions include comprehensive visualization of large data sets generated by the model and a significant increase in user-simulation interactivity. We developed a highly-interactive remote simulation and visualization framework for vocal fold (VF) agent-based modeling (ABM). The 3D VF ABM was verified through comparisons with empirical vocal fold data. Representative trends of biomarker predictions in surgically injured vocal folds were observed. The physiologically representative human VF ABM consisted of more than 15 million mobile biological cells. The model maintained and generated 1.7 billion signaling and extracellular matrix (ECM) protein data points in each iteration. The VF ABM employed HPC techniques to optimize its performance by concurrently utilizing the power of multi-core CPU and multiple GPUs. The optimization techniques included the minimization of data transfer between the CPU host and the rendering GPU. These transfer minimization techniques also reduced transfers between peer GPUs in multi-GPU setups. The data transfer minimization techniques were executed with a scheduling scheme that aims to achieve load balancing, maximum overlap of computation and communication, and a high degree of interactivity. This scheduling scheme achieved optimal interactivity by hyper-tasking the available GPUs (GHT). In comparison to the original serial implementation on a popular ABM framework, NetLogo, these schemes have shown substantial performance improvements of 400x and 800x for the 2D and 3D model, respectively. Furthermore, the combination of data footprint and data transfer reduction techniques with GHT achieved high-interactivity visualization with an average framerate of 42.8 fps. This performance enabled the users to perform real-time data exploration on large simulated outputs and steer the course of their simulation as needed.Item Adaptive Agent Modeling in a Policy Context(2004-12-15) Gulden, Timothy R; Daly, Herman E; Public Affairs; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the utility of adaptive agent modeling (also referred to as agent-based modeling or individual based modeling) as a tool in public policy research. It uses the adaptive agent technique to produce useful results in three diverse areas. It demonstrates that the adaptive agent framework can be used to extend traditional models of comparative advantage in international trade, showing that the presence of increasing returns to scale in some industries shifts the basis of comparative advantage arguments, making room for industrial policy and the regulation of trade. Next, the dissertation demonstrates that the size distribution of cities within nations, generally thought to approximate the "Zipf" distribution, can be reproduced using a simple agent-based model. This model produces insights into the evolution of the distribution as well as departures from it especially in France and Russia. This understanding of urban dynamics has implications for easing the structural transition of the Russian economy and for designing policies to reduce the size of megacities in the developing world. The dissertation goes on to examine individual level data from the Guatemalan civil war from an adaptive agent modeling perspective. It finds several novel patterns in the data which may serve as benchmarks for adaptive agent modeling efforts and suggests avenues by which existing conflict models might be brought into closer accord with the data. The dissertation concludes that adaptive agent modeling is useful in a policy context because it allows quantitative work to be done while relaxing some of the unrealistic assumptions which are often required to gain analytical traction using traditional methods. The method is found to be particularly useful in situations where path dependence, heterogeneity of actors, bounded rationality, and imperfect information are significant features of the system under examination. The individual based nature of the method is also found to be well suited to assessing distributional impacts of changes in process or policy.