Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Graph search"”.
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Towards a concurrent implementation of keyword search over relational databases.
… keyword queries. We further this by implementing graph search, allowing users to automatically discover related facts of information. The effects of performing graph search concurrently are explored, revealing a substantial reduction in graph search run-time over the serial implementation.
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Deep reinforcement learning on 1-layer circuit routing problem
… the routing problem is solved using graph search techniques such as Lee’s algorithm. The result produced by graph search algorithms relies heavily on the order of routing. While some simple heuristics are available, the result is not stable because simple heuristics take greedy …
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Creating Interactive Experiences and Visualizing Computer Science Concepts to aid Student Understanding
… scratch. For example, when we first introduce graph search in an intro to computational thinking class, although we use a variety of visual aids, we never give the students a way to run and visualize the algorithms in action on some examples. We have them write code that eventually builds up to …
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Cooperative Collision Avoidance for the Voyager Unmanned Ground Vehicle: Practical Implementation and Demonstration
The following thesis presents the research work done in practically implementing a cooperative collision avoidance system on the Voyager mobile robotic platform provided by the CSIR. The project adapts approaches proposed by Hughes for unmanned aerial vehicles and adapts and practically implements …
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Computational modelling of agent based path planning and the representation of human wayfinding behaviour within egress models
… of the environment, implementation of graph search algorithms to generate choice set of routes for the agents to choose from, determination of factors that influence people‟s wayfinding behaviour and the development/integration of the agent based wayfinding model within the …
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A systematic analysis of defenses against code reuse attacks
… bypasses. Next, we investigate the control flow graphs enforced by proposed control flow integrity (CFI) systems. We model the behavior of these systems using a graph search. We also develop several code reuse payloads that work within the control flow graph enforced by one proposed CFI defense. …
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Probabilistic roadmaps in uncertain environments
… are an efficient method for generating motion graphs through the robot's configuration space, but do not inherently represent any uncertainty in the environment. In this thesis, the physical domain is abstracted into a graph search problem where the states of some edges are unknown. This is …
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Field D* pathfinding in weighted simplicial complexes
… a complex environment is a continuing area of research within Computer Science. When such environments can be represented as a graph, established graph search algorithms, such as Dijkstra’s shortest path and A*, can be used. However, many environments are constructed from a set of regions that do …
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Graph Based Optimization For Scientific Computing
… analysis, system simulation into abstract graph problems and developing algorithms for optimization. First, we investigate an efficient algorithm for unequal genome phylogeny reconstruction. Currently few methods can solve the median problem for unequal genomes which is essential in …
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A geographic knowledge discovery approach to property valuation
… discovery can be applied in the area Geographic Information Science. In particular, its application in the area of property valuation in order to reveal how different spatial entities and their interactions affect the price of the properties is explored. This approach is entirely data …
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Motion Primitives and Planning for Robots with Closed Chain Systems and Changing Topologies
… to trust and anticipate its behavior. Heuristic search-based planning offers predictable motions and guarantees on completeness and sub-optimality of solutions. While search-based planning on motion primitive-based (lattice-based) graphs has been used extensively in navigation, application to …
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Terrain aware tactical motion planning and control algorithms for off-road UGVs in GNSS denied hostile environments
… interference or structural constraints. The research focuses on enabling autonomous navigation in uncharted, hostile terrains by developing a hierarchical autonomy stack that seamlessly integrates navigation, path planning, trajectory planning, and control functionalities. The navigation system …
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A general index heuristic for search with mobile agents
This dissertation considers a suite of search problems in which agents are trying to find goals in minimum expected time. Unlike search in data structures in which time is measured by a number operations, search in metric spaces measures time by units of distance and has received much less …
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Distances on rankings: from social choice to flash memories
… these distances. The algorithms are based on graph-search techniques, Viterbi-type algorithms, and dynamic programming. Furthermore, we present algorithms for rank aggregation using the proposed distances. One algorithm is based on finding a minimum weight bipartite matching and another is a …
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Freeform, direct-write assembly of thermoplastics and glasses: Theory, practice, and applications
… of a feasible sequence is NP-complete. A graph-search approach to finding an optimal sequence, which maximizes the frame fidelity and minimizes the probably of assembly failure, is developed, implemented and validated by printing designs comprising thousands of beams. The freeform assembly …
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Two-Step System Identification and Primitive-Based Motion Planning for Control of Small Unmanned Aerial Vehicles
… The motion planning task is posed as a search over a directed graph, and the applicability of informed graph search techniques is investigated. Specifically, a locally greedy algorithm with effective backtracking ability is developed and compared to weighted A* search. The greedy …
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Tradespace exploration for space system architectures : a weighted graph framework
… generation of a directed, weighted 'tradespace graph' that serves as a model of the architecture decision making process. Vertices in the tradespace graph are defined by pairings of architectures from the tradespace with asset portfolios, which are the sets of the common elements shared between …
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Lower Bounds and Algorithms for Searching Networks
Research on graph searching has recently gained interest in computer science, mathematics, and physics. This thesis provides new results on two graph search models, namely fast searching and the zero-visibility cops and robber model. Given a graph that contains an invisible fugitive, the fast …
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New Sequential and Scalable Parallel Algorithms for Incomplete Factor Preconditioning
… a sequence of lemmas and theorems that provide graph theoretic characterizations of both definitions; these characterizations are based on the static graph of a matrix, <em>G</em>(<em>A</em>).</p> <p>Our Incomplete Fill Path Theorem characterizes fill levels per the sum definition; this is the …
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Geodesic Problems for Mobile Robots
… condition yields a nonholonomic bitangency graph which is a network of collision-free trajectories in which the solution is sought. In general, our nonholonomic bitangency graph is a 2-dimensional subset of the 3-dimensional configuration space of the robot. Therefore, further optimization …
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