157 research outputs found

    optimización da planificación de adquisición de datos LIDAR cara ó modelado 3D de interiores

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    The main objective of this doctoral thesis is the design, validation and implementation of methodologies that allow the geometric and topological modelling of navigable spaces, whether inside buildings or urban environments, to be integrated into three-dimensional geographic information systems (GIS-3D). The input data of this work will consist mainly of point clouds (which can be classified) acquired by LiDAR systems both indoors and outdoors. In addition, the use of BIM infrastructure models and cadastral maps is proposed depending on their availability. Point clouds provide a large amount of environmental information with high accuracy compared to data offered by other acquisition technologies. However, the lack of data structure and volume requires a great deal of processing effort. For this reason, the first step is to structure the data by dividing the input cloud into simpler entities that facilitate subsequent processes. For this first division, the physical elements present in the cloud will be considered, since they can be walls in the case of interior environments or kerbs in the case of exteriors. In order to generate navigation routes adapted to different mobile agents, the next objective will try to establish a semantic subdivision of space according to the functionalities of space. In the case of internal environments, it is possible to use BIM models to evaluate the results and the use of cadastral maps that support the division of the urban environment. Once the navigable space is divided, the design of topologically coherent navigation networks will be parameterized both geometrically and topologically. For this purpose, several spatial discretization techniques, such as 3D tessellations, will be studied to facilitate the establishment of topological relationships, adjacency, connectivity and inclusion between subspaces. Based on the geometric characterization and the topological relations established in the previous phase, the creation of three-dimensional navigation networks with multimodal support will be addressed and different levels of detail will be considered according to the mobility specifications of each agent and its purpose. Finally, the possibility of integrating the networks generated in a GIS-3D visualization system will be considered. For the correct visualization, the level of detail can be adjusted according to geometry and semantics. Aspects such as the type of user or transport, mobility, rights of access to spaces, etc. They must be considered at all times.El objetivo principal de esta tesis doctoral es el diseño, la validación y la implementación de metodologías que permitan el modelado geométrico y topológico de espacios navegables, ya sea de interiores de edificios o entornos urbanos, para integrarse en sistemas de información geográfica tridimensional (SIG). -3D). Los datos de partida de este trabajo consistirán principalmente en nubes de puntos (que pueden estar clasificados) adquiridas por sistemas LiDAR tanto en interiores como en exteriores. Además, se propone el uso de modelos BIM de infraestructuras y mapas catastrales en función de su disponibilidad. Las nubes de puntos proporcionan una gran cantidad de información del entorno con gran precisión con respecto a los datos ofrecidos por otras tecnologías de adquisición. Sin embargo, la falta de estructura de datos y su volumen requiere un gran esfuerzo de procesamiento. Por este motivo, el primer paso que se debe realizar consiste en estructurar los datos dividiendo la nube de entrada en entidades más simples que facilitan los procesos posteriores. Para esta primera división se considerarán los elementos físicos presentes en la nube, ya que pueden ser paredes en el caso de entornos interiores o bordillos en el caso de los exteriores. Con el propósito de generar rutas de navegación adaptadas a diferentes agentes móviles, el próximo objetivo intentará establecer una subdivisión semántica del espacio de acuerdo con las funcionalidades del espacio. En el caso de entornos internos, es posible utilizar modelos BIM para evaluar los resultados y el uso de mapas catastrales que sirven de apoyo en la división del entorno urbano. Una vez que se divide el espacio navegable, se parametrizará tanto geométrica como topológicamente al diseño de redes de navegación topológicamente coherentes. Para este propósito, se estudiarán varias técnicas de discretización espacial, como las teselaciones 3D, para facilitar el establecimiento de relaciones topológicas, la adyacencia, la conectividad y la inclusión entre subespacios. A partir de la caracterización geométrica y las relaciones topológicas establecidas en la fase anterior, se abordará la creación de redes de navegación tridimensionales con soporte multimodal y se considerarán diversos niveles de detalle según las especificaciones de movilidad de cada agente y su propósito. Finalmente, se contemplará la posibilidad de integrar las redes generadas en un sistema de visualización tridimensional 3D SIG 3D. Para la correcta visualización, el nivel de detalle se puede ajustar en función de la geometría y la semántica. Aspectos como el tipo de usuario o transporte, movilidad, derechos de acceso a espacios, etc. Deben ser considerados en todo momento.O obxectivo principal desta tese doutoral é o deseño, validación e implementación de metodoloxías que permitan o modelado xeométrico e topolóxico de espazos navegables, ben sexa de interiores de edificios ou de entornos urbanos, ca fin de seren integrados en Sistemas de Información Xeográfica tridimensionais (SIX-3D). Os datos de partida deste traballo constarán principalmente de nubes de puntos (que poden estar clasificadas) adquiridas por sistemas LiDAR tanto en interiores como en exteriores. Ademáis plantease o uso de modelos BIM de infraestruturas e mapas catastrais dependendo da súa dispoñibilidade. As nubes de puntos proporcionan unha gran cantidade de información do entorno cunha gran precisión respecto os datos que ofrecen outras tecnoloxías de adquisición. Sen embargo, a falta de estrutura dos datos e a seu volume esixe un amplo esforzo de procesado. Por este motivo o primeiro paso a levar a cabo consiste nunha estruturación dos datos mediante a división da nube de entrada en entidades máis sinxelas que faciliten os procesos posteriores. Para esta primeira división consideraranse elementos físicos presentes na nube como poden ser paredes no caso de entornos interiores ou bordillos no caso de exteriores. Coa finalidade de xerar rutas de navegación adaptadas a distintos axentes móbiles, o seguinte obxectivo tratará de establecer unha subdivisión semántica do espazo de acordo as funcionalidades do espazo. No caso de entornos interiores plantease a posibilidade de empregar modelos BIM para avaliar os resultados e o uso de mapas catastrais que sirvan de apoio na división do entorno urbano. Unha vez divido o espazo navigable parametrizarase tanto xeométricamente como topolóxicamene de cara ao deseño de redes de navegación topolóxicamente coherentes. Para este fin estudaranse varias técnicas de discretización de espazos como como son as teselacións 3D co obxectivo de facilitar establecer relacións topolóxicas, de adxacencia, conectividade e inclusión entre subespazos. A partir da caracterización xeométrica e das relación topolóxicas establecidas na fase previa abordarase a creación de redes de navegación tridimensionais con soporte multi-modal e considerando varios niveis de detalle de acordo as especificacións de mobilidade de cada axente e a súa finalidade. Finalmente comtemplarase a posibilidade de integrar as redes xeradas nun sistema SIX 3D visualización tridimensional. Para a correcta visualización o nivel de detalle poderá axustarse en base a xeometría e a semántica. Aspectos como o tipo de usuario ou transporte, mobilidade, dereitos de acceso a espazos, etc. deberán ser considerados en todo momento

    The role of semaphorins in response to injury in C. elegans neurons

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    When neural tissue is injured by trauma, delicate neuronal processes such as axons and dendrites are prone to lesion damage and often disconnect. The molecular, cellular, and circuit mechanisms that underlie the regrowth and reconnection of these processes and the recovery of behavior are major challenges in the fields of neuroscience, regeneration, and resilience. At the molecular and cellular levels, signaling pathways that mediate neuronal growth cone guidance during development can play a role in neuronal regeneration and recovery from injury. One family of signaling proteins involved in this process comprises the highly conserved semaphorins and their receptors, the plexins. Across various species, from C. elegans to humans, semaphorins and plexins are crucial for axon pathfinding and synapse formation during development. In the mammalian nervous system, the semaphorin signaling system is comprised of more than 20 semaphorins and 9 plexins, whereas the C. elegans genome only encodes 3 semaphorins and 2 plexin receptors. Among them, the transmembrane semaphorins, SMP-1 and SMP-2, signal through their receptor PLX-1, while the secreted semaphorin MAB-20, signals through PLX-2. This dissertation explores the role of semaphorin signaling in neuroregeneration in vivo, by making use of the experimental advantages of Caenorhabditis elegans. Importantly, this versatile model animal has the natural ability to regenerate neuronal processes after injury and optic methods were developed to precisely disconnect single neurites in otherwise intact animals using laser microsurgery. Moreover, the semaphorin system is relatively simple and genetically amenable, and transgenic, microscopy and behavior analysis methods are well established. The development and assessment of a new laser microsurgery system as part of this thesis allowed reliable and accurate disconnection of identifiable axons and dendrites. The elucidated expression patterns and involvement of C. elegans semaphorins in neural regeneration have shed significant light with regard to the role this pathway plays in C. elegans regeneration and added to the field of knowledge of neural regeneration research. The findings reveal that regrowth and reconnection are more prevalent in the absence of both plexin receptors and the secreted semaphorin MAB-20. This suggests that the semaphorin signaling in this system restricts neural growth, possibly to prevent aberrant reconnection. The membrane-bound SMP-1 and SMP-2 might have a redundant role, signaling through PLX-1. These results align with the inhibitory effects of semaphorin signaling on axonal growth and guidance during development in the mammalian system. Therefore, secreted and membrane-bound semaphorin signaling pathways restrict regeneration using distinct processes, likely involving spatial specificity and recurrent signals. Findings such as the ones presented in this thesis delve deeper into the mechanisms and factors involved in promoting regeneration and aid to uncover valuable insights that could assist in overcoming the challenges faced by regenerative medicine in treating central nervous system injuries and disorders

    Group navigation in RTS games using flow networks over flow field regions

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    This thesis explores the challenges of implementing effective navigation for groups of units in real-time strategy computer games, specifically focusing on the movement of large numbers of homogeneous units across a two-dimensional grid-based map. The thesis presents a pathfinding algorithm that could be used in RTS games. The algorithm enables the units to utilize multiple paths effectively by modeling the unit navigation as a flow network problem. The units use precomputed flow fields during the navigation. This allows for faster pathfinding times by offloading part of the computation to the preprocessing. The algorithm's performance is evaluated against a baseline solution using the A* algorithm and other existing solutions. Comparative analysis will be conducted utilizing maps from the Moving AI 2D Pathfinding Benchmark dataset to assess the efficacy of the proposed solution. 1Tato diplomová práce zkoumá problém implementace efektivní navigace pro skupiny jednotek v real-time strategických počítačových hrách, konkrétně na pohych velkého množství stejnorodých jednotek na dvou-dimenzionální mapě. Práce navrhuje navigační algoritmus, který by bylo možné použít v RTS hrách. Algo- ritmus umožňuje jednotkám efektivně využit alternativní cesty díky modelování navigace jednotek pomocí toků v síti. Jednotky během své navigace používají předpočítaná vek- torová pole. To umožňuje dosažení rychlejšího nalezení cesty díky přesunutí části výpočtu do fáze preprocessingu. Efektivita algoritmu je porovnána proti základním řešenim využívajícím A*, nebo a jiné běžné navigační algoritmy. K posouzení účinnosti navrhovaného algorimu bude prove- dena srovnávací analýza s využitím map z datového souboru Moving AI 2D Pathfinding Benchmark. 1Department of Software and Computer Science EducationKatedra softwaru a výuky informatikyFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

    Optimal Path Planning in Distinct Topo-Geometric Classes using Neighborhood-augmented Graph and its Application to Path Planning for a Tethered Robot in 3D

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    Many robotics applications benefit from being able to compute multiple locally optimal paths in a given configuration space. Examples include path planning for of tethered robots with cable-length constraints, systems involving cables, multi-robot topological exploration & coverage, and, congestion reduction for mobile robots navigation without inter-robot coordination. Existing paradigm is to use topological path planning methods that can provide optimal paths from distinct topological classes available in the underlying configuration space. However, these methods usually require non-trivial and non-universal geometrical constructions, which are prohibitively complex or expensive in 3 or higher dimensional configuration spaces with complex topology. Furthermore, topological methods are unable to distinguish between locally optimal paths that belong to the same topological class but are distinct because of genus-zero obstacles in 3D or due to high-cost or high-curvature regions. In this paper we propose an universal and generalized approach to multi-class path planning using the concept of a novel neighborhood-augmented graph, search-based planning in which can compute paths in distinct topo-geometric classes. This approach can find desired number of locally optimal paths in a wider variety of configuration spaces without requiring any complex pre-processing or geometric constructions. Unlike the existing topological methods, resulting optimal paths are not restricted to distinct topological classes, thus making the algorithm applicable to many other problems where locally optimal and geometrically distinct paths are of interest. For the demonstration of an application of the proposed approach, we implement our algorithm to planning for shortest traversible paths for a tethered robot with cable-length constraint navigating in 3D and validate it in simulations & experiments.Comment: 18 pages, 17 figure

    Mars delivery service - development of the electro-mechanical systems of the Sample Fetch Rover for the Mars Sample Return Campaign

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    This thesis describes the development of the Sample Fetch Rover (SFR), studied for Mars Sample Return (MSR), an international campaign carried out in cooperation between the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The focus of this document is the design of the electro-mechanical systems of the rover. After placing this work into the general context of robotic planetary exploration and summarising the state of the art for what concerns Mars rovers, the architecture of the Mars Sample Return Campaign is presented. A complete overview of the current SFR architecture is provided, touching upon all the main subsystems of the spacecraft. For each area, it is discussed what are the design drivers, the chosen solutions and whether they use heritage technology (in particular from the ExoMars Rover) or new developments. This research focuses on two topics of particular interest, due to their relevance for the mission and the novelty of their design: locomotion and sample acquisition, which are discussed in depth. The early SFR locomotion concepts are summarised, covering the initial trade-offs and discarded designs for higher traverse performance. Once a consolidated architecture was reached, the locomotion subsystem was developed further, defining the details of the suspension, actuators, deployment mechanisms and wheels. This technology is presented here in detail, including some key analysis and test results that support the design and demonstrate how it responds to the mission requirements. Another major electro-mechanical system developed as part of this work is the one dedicated to sample tube acquisition. The concept of operations of this machinery was defined to be robust against the unknown conditions that characterise the mission. The design process led to a highly automated robotic system which is described here in its main components: vision system, robotic arm and tube storage

    LIPIcs, Volume 258, SoCG 2023, Complete Volume

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    LIPIcs, Volume 258, SoCG 2023, Complete Volum

    New methodological approaches of investigating the identity of Historic Settlement

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    Para estabelecer a “identidade” de um sítio histórico, a utilização de uma metodologia baseada na aplicação de ferramentas de mapeamento para análise de indicadores tangíveis e intangíveis pode ser de grande interesse e significância, uma vez que esta metodologia ainda não tem sido amplamente utilizada em pesquisas patrimoniais. apesar de ser uma ferramenta poderosa. Nesse tipo de mapeamento, a paisagem, a arquitetura e as camadas de mudança que foram depositadas no território sobre elas, ao longo dos tempos. são consideradas indicadores tangíveis, enquanto a toponímia, a história, a memória e os antigos dizeres locais são considerados indicadores intangíveis. Os indicadores, sua existência, geolocalizações, processos, significado e distribuição espacial, transformações etc. devem ser mapeados em diferentes camadas e posteriormente alguns conjuntos e subconjuntos devem ser justapostos para obter combinações e resultados. Portanto, informações produzidas a partir destes indicadores tangíveis e intangíveis de forma científica e matemática, apoiadas na história, artefactos e vestígios, princípios de urbanismo, inscrições e manuscritos, podem revelar muitos aspetos desconhecidos dos sítios históricos. Os métodos precisam ser de natureza mais científica e objetiva para excluir o viés de uma perceção distorcida. Também é uma boa técnica testar o método em mais de um local que tenha antecedentes diferentes, mas configuração semelhante, a fim de provar a validade e eficácia universal do método. Assim, Khalifatabad (Bangladesh) e Évora (Portugal) são os dois locais de um estudo de caso que visa testar a metodologia acima referida, uma vez que ambos foram declarados Património Mundial da UNESCO e possuem valor histórico semelhante; New methodological approaches of investigating the identity of Historic Settlement Abstract: In order to establish the identity of an ancient settlement, the use of a methodology based on the application of mapping tools for analysis of tangible and intangible indicators might be of great interest and significance, as this methodology has not yet been extensively used in heritage research despite of its being a powerful tool. In this kind of mapping, landscape, architecture and the layers of change that have been deposited on them throughout ages are considered as tangible indicators, while toponymy, story, memory and ancient local sayings are considered as intangible indicators. The indicators, their existence, geo locations, processes, spatial significance and distribution, transformations etc. are to be mapped in different layers and later some set and subsets are to be juxtaposed to obtain certain combinations and results. Therefore information produced from both tangible and intangible indicators in a scientific and mathematical manner, supported by history, artefacts and vestiges, principles of urbanism, inscriptions and manuscripts, can reveal many unknown aspects of historic sites. The methods need to be more scientific and objective in nature to exclude biasness of perception. It is also a good technique to test the method on more than one site that has different background but similar configuration in order to prove the validity and efficacy of the method. Therefore Khalifatabad (Bangladesh) and Évora (Portugal) are the two sites of a case study that aims to test the above mentioned methodology, as they both were declared UNESCO World Heritage and carry similar historic value

    Content-aware approach for improving biomedical image analysis: an interdisciplinary study series

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    Biomedicine is a highly interdisciplinary research area at the interface of sciences, anatomy, physiology, and medicine. In the last decade, biomedical studies have been greatly enhanced by the introduction of new technologies and techniques for automated quantitative imaging, thus considerably advancing the possibility to investigate biological phenomena through image analysis. However, the effectiveness of this interdisciplinary approach is bounded by the limited knowledge that a biologist and a computer scientist, by professional training, have of each other’s fields. The possible solution to make up for both these lacks lies in training biologists to make them interdisciplinary researchers able to develop dedicated image processing and analysis tools by exploiting a content-aware approach. The aim of this Thesis is to show the effectiveness of a content-aware approach to automated quantitative imaging, by its application to different biomedical studies, with the secondary desirable purpose of motivating researchers to invest in interdisciplinarity. Such content-aware approach has been applied firstly to the phenomization of tumour cell response to stress by confocal fluorescent imaging, and secondly, to the texture analysis of trabecular bone microarchitecture in micro-CT scans. Third, this approach served the characterization of new 3-D multicellular spheroids of human stem cells, and the investigation of the role of the Nogo-A protein in tooth innervation. Finally, the content-aware approach also prompted to the development of two novel methods for local image analysis and colocalization quantification. In conclusion, the content-aware approach has proved its benefit through building new approaches that have improved the quality of image analysis, strengthening the statistical significance to allow unveiling biological phenomena. Hopefully, this Thesis will contribute to inspire researchers to striving hard for pursuing interdisciplinarity

    Event-Driven Technologies for Reactive Motion Planning: Neuromorphic Stereo Vision and Robot Path Planning and Their Application on Parallel Hardware

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    Die Robotik wird immer mehr zu einem Schlüsselfaktor des technischen Aufschwungs. Trotz beeindruckender Fortschritte in den letzten Jahrzehnten, übertreffen Gehirne von Säugetieren in den Bereichen Sehen und Bewegungsplanung noch immer selbst die leistungsfähigsten Maschinen. Industrieroboter sind sehr schnell und präzise, aber ihre Planungsalgorithmen sind in hochdynamischen Umgebungen, wie sie für die Mensch-Roboter-Kollaboration (MRK) erforderlich sind, nicht leistungsfähig genug. Ohne schnelle und adaptive Bewegungsplanung kann sichere MRK nicht garantiert werden. Neuromorphe Technologien, einschließlich visueller Sensoren und Hardware-Chips, arbeiten asynchron und verarbeiten so raum-zeitliche Informationen sehr effizient. Insbesondere ereignisbasierte visuelle Sensoren sind konventionellen, synchronen Kameras bei vielen Anwendungen bereits überlegen. Daher haben ereignisbasierte Methoden ein großes Potenzial, schnellere und energieeffizientere Algorithmen zur Bewegungssteuerung in der MRK zu ermöglichen. In dieser Arbeit wird ein Ansatz zur flexiblen reaktiven Bewegungssteuerung eines Roboterarms vorgestellt. Dabei wird die Exterozeption durch ereignisbasiertes Stereosehen erreicht und die Pfadplanung ist in einer neuronalen Repräsentation des Konfigurationsraums implementiert. Die Multiview-3D-Rekonstruktion wird durch eine qualitative Analyse in Simulation evaluiert und auf ein Stereo-System ereignisbasierter Kameras übertragen. Zur Evaluierung der reaktiven kollisionsfreien Online-Planung wird ein Demonstrator mit einem industriellen Roboter genutzt. Dieser wird auch für eine vergleichende Studie zu sample-basierten Planern verwendet. Ergänzt wird dies durch einen Benchmark von parallelen Hardwarelösungen wozu als Testszenario Bahnplanung in der Robotik gewählt wurde. Die Ergebnisse zeigen, dass die vorgeschlagenen neuronalen Lösungen einen effektiven Weg zur Realisierung einer Robotersteuerung für dynamische Szenarien darstellen. Diese Arbeit schafft eine Grundlage für neuronale Lösungen bei adaptiven Fertigungsprozesse, auch in Zusammenarbeit mit dem Menschen, ohne Einbußen bei Geschwindigkeit und Sicherheit. Damit ebnet sie den Weg für die Integration von dem Gehirn nachempfundener Hardware und Algorithmen in die Industrierobotik und MRK
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