119 research outputs found

    Algorithms for Triangles, Cones & Peaks

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    Three different geometric objects are at the center of this dissertation: triangles, cones and peaks. In computational geometry, triangles are the most basic shape for planar subdivisions. Particularly, Delaunay triangulations are a widely used for manifold applications in engineering, geographic information systems, telecommunication networks, etc. We present two novel parallel algorithms to construct the Delaunay triangulation of a given point set. Yao graphs are geometric spanners that connect each point of a given set to its nearest neighbor in each of kk cones drawn around it. They are used to aid the construction of Euclidean minimum spanning trees or in wireless networks for topology control and routing. We present the first implementation of an optimal O(nlog⁥n)\mathcal{O}(n \log n)-time sweepline algorithm to construct Yao graphs. One metric to quantify the importance of a mountain peak is its isolation. Isolation measures the distance between a peak and the closest point of higher elevation. Computing this metric from high-resolution digital elevation models (DEMs) requires efficient algorithms. We present a novel sweep-plane algorithm that can calculate the isolation of all peaks on Earth in mere minutes

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    LIPIcs, Volume 258, SoCG 2023, Complete Volume

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    LIPIcs, Volume 258, SoCG 2023, Complete Volum

    LIPIcs, Volume 244, ESA 2022, Complete Volume

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    LIPIcs, Volume 244, ESA 2022, Complete Volum

    Bowdoin College Catalogue and Academic Handbook (2021-2022)

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    https://digitalcommons.bowdoin.edu/course-catalogues/1319/thumbnail.jp

    Mobile Robots

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    The objective of this book is to cover advances of mobile robotics and related technologies applied for multi robot systems' design and development. Design of control system is a complex issue, requiring the application of information technologies to link the robots into a single network. Human robot interface becomes a demanding task, especially when we try to use sophisticated methods for brain signal processing. Generated electrophysiological signals can be used to command different devices, such as cars, wheelchair or even video games. A number of developments in navigation and path planning, including parallel programming, can be observed. Cooperative path planning, formation control of multi robotic agents, communication and distance measurement between agents are shown. Training of the mobile robot operators is very difficult task also because of several factors related to different task execution. The presented improvement is related to environment model generation based on autonomous mobile robot observations

    Hierarchical processing, editing and rendering of acquired geometry

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    La reprĂ©sentation des surfaces du monde rĂ©el dans la mĂ©moire d’une machine peut dĂ©sormais ĂȘtre obtenue automatiquement via divers pĂ©riphĂ©riques de capture tels que les scanners 3D. Ces nouvelles sources de donnĂ©es, prĂ©cises et rapides, amplifient de plusieurs ordres de grandeur la rĂ©solution des surfaces 3D, apportant un niveau de prĂ©cision Ă©levĂ© pour les applications nĂ©cessitant des modĂšles numĂ©riques de surfaces telles que la conception assistĂ©e par ordinateur, la simulation physique, la rĂ©alitĂ© virtuelle, l’imagerie mĂ©dicale, l’architecture, l’étude archĂ©ologique, les effets spĂ©ciaux, l’animation ou bien encore les jeux video. Malheureusement, la richesse de la gĂ©omĂ©trie produite par ces mĂ©thodes induit une grande, voire gigantesque masse de donnĂ©es Ă  traiter, nĂ©cessitant de nouvelles structures de donnĂ©es et de nouveaux algorithmes capables de passer Ă  l’échelle d’objets pouvant atteindre le milliard d’échantillons. Dans cette thĂšse, je propose des solutions performantes en temps et en espace aux problĂšmes de la modĂ©lisation, du traitement gĂ©omĂ©trique, de l’édition intĂ©ractive et de la visualisation de ces surfaces 3D complexes. La mĂ©thodologie adoptĂ©e pendant l’élaboration transverse de ces nouveaux algorithmes est articulĂ©e autour de 4 Ă©lĂ©ments clĂ©s : une approche hiĂ©rarchique systĂ©matique, une rĂ©duction locale de la dimension des problĂšmes, un principe d’échantillonage-reconstruction et une indĂ©pendance Ă  l’énumĂ©ration explicite des relations topologiques aussi appelĂ©e approche basĂ©e-points. En pratique, ce manuscrit propose un certain nombre de contributions, parmi lesquelles : une nouvelle structure hiĂ©rarchique hybride de partitionnement, l’Arbre Volume-Surface (VS-Tree) ainsi que de nouveaux algorithmes de simplification et de reconstruction ; un systĂšme d’édition intĂ©ractive de grands objets ; un noyau temps-rĂ©el de synthĂšse gĂ©omĂ©trique par raffinement et une structure multi-rĂ©solution offrant un rendu efficace de grands objets. Ces structures, algorithmes et systĂšmes forment une chaĂźne capable de traiter les objets en provenance du pipeline d’acquisition, qu’ils soient reprĂ©sentĂ©s par des nuages de points ou des maillages, possiblement non 2-variĂ©tĂ©s. Les solutions obtenues ont Ă©tĂ© appliquĂ©es avec succĂšs aux donnĂ©es issues des divers domaines d’application prĂ©citĂ©s.Digital representations of real-world surfaces can now be obtained automatically using various acquisition devices such as 3D scanners and stereo camera systems. These new fast and accurate data sources increase 3D surface resolution by several orders of magnitude, borrowing higher precision to applications which require digital surfaces. All major computer graphics applications can take benefit of this automatic modeling process, including: computer-aided design, physical simulation, virtual reality, medical imaging, architecture, archaeological study, special effects, computer animation and video games. Unfortunately, the richness of the geometry produced by these media comes at the price of a large, possibility gigantic, amount of data which requires new efficient data structures and algorithms offering scalability for processing such objects. This thesis proposes time and space efficient solutions for modeling, editing and rendering such complex surfaces, solving these problems with new algorithms sharing 4 fundamental elements: a systematic hierarchical approach, a local dimension reduction, a sampling-reconstruction paradigm and a pointbased basis. Basically, this manuscript proposes several contributions, including: a new hierarchical space subdivision structure, the Volume-Surface Tree, for geometry processing such as simplification and reconstruction; a streaming system featuring new algorithms for interactive editing of large objects, an appearancepreserving multiresolution structure for efficient rendering of large point-based surfaces, and a generic kernel for real-time geometry synthesis by refinement. These elements form a pipeline able to process acquired geometry, either represented by point clouds or non-manifold meshes. Effective results have been successfully obtained with data coming from the various applications mentioned

    High-Performance Modelling and Simulation for Big Data Applications

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    This open access book was prepared as a Final Publication of the COST Action IC1406 “High-Performance Modelling and Simulation for Big Data Applications (cHiPSet)“ project. Long considered important pillars of the scientific method, Modelling and Simulation have evolved from traditional discrete numerical methods to complex data-intensive continuous analytical optimisations. Resolution, scale, and accuracy have become essential to predict and analyse natural and complex systems in science and engineering. When their level of abstraction raises to have a better discernment of the domain at hand, their representation gets increasingly demanding for computational and data resources. On the other hand, High Performance Computing typically entails the effective use of parallel and distributed processing units coupled with efficient storage, communication and visualisation systems to underpin complex data-intensive applications in distinct scientific and technical domains. It is then arguably required to have a seamless interaction of High Performance Computing with Modelling and Simulation in order to store, compute, analyse, and visualise large data sets in science and engineering. Funded by the European Commission, cHiPSet has provided a dynamic trans-European forum for their members and distinguished guests to openly discuss novel perspectives and topics of interests for these two communities. This cHiPSet compendium presents a set of selected case studies related to healthcare, biological data, computational advertising, multimedia, finance, bioinformatics, and telecommunications

    Humanoid Robots

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    For many years, the human being has been trying, in all ways, to recreate the complex mechanisms that form the human body. Such task is extremely complicated and the results are not totally satisfactory. However, with increasing technological advances based on theoretical and experimental researches, man gets, in a way, to copy or to imitate some systems of the human body. These researches not only intended to create humanoid robots, great part of them constituting autonomous systems, but also, in some way, to offer a higher knowledge of the systems that form the human body, objectifying possible applications in the technology of rehabilitation of human beings, gathering in a whole studies related not only to Robotics, but also to Biomechanics, Biomimmetics, Cybernetics, among other areas. This book presents a series of researches inspired by this ideal, carried through by various researchers worldwide, looking for to analyze and to discuss diverse subjects related to humanoid robots. The presented contributions explore aspects about robotic hands, learning, language, vision and locomotion
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