89 research outputs found

    Efficient Solutions in Path Planning for Autonomous Mobile Robots

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    Fecha de lectura de Tesis: 25 julio 2018.Los robots, máquinas que desempeñan un abanico de tareas de lo más variopinto. Desde realizar tareas muy específicas en cadenas de montaje hasta desempeñar la mayoría de labores cotidianas que los seres humanos tenemos que afrontar cada día. Como se puede intuir, para esto se necesitan no solo máquinas, sino máquinas dotadas de cierta inteligencia, que surge de la necesidad de que las máquinas abandonen su estatismo y monotonía para comenzar a enfrentarse a un mundo dinámico y ambiguo: nuestro mundo. El principal desencadenante que ha llevado al ser humano a dotar de inteligencia y movilidad a las máquinas es su afán de dominar y, al mismo tiempo, liberarse de un entorno cada vez más estresante. Hay dos aspectos irrefutables que marcan la versatilidad de una máquina: su inteligencia y su movilidad. Hablando de robótica y movilidad surge el problema de cómo y por dónde debe moverse un robot para alcanzar un determinado objetivo sin comprometer su integridad física. Como el significado de moverse puede ser muy amplio, aquí hablaremos de desplazamiento, en el sentido literal de viajar. Y cuando viajamos a algún lugar siempre nos preguntamos lo siguiente: ¿Por dónde vamos? y ¿Cuál es el la mejor alternativa?. Esta problemática, en robótica, se conoce como el problema del Path Planning. En esta tesis doctoral se aborda, de manera innovadora y altamente paralela, el problema del Path Planing sobre mapas reales extensos en un contexto de tiempo real. Este grado de paralelismo se consigue gracias al uso intensivo de las populares GPU (Unidad Gráfica de Procesamiento) y de los bien conocidos chips multi-core. Pero aquí no solo se aborda el problema del Path Planning desde un punto de vista altamente paralelo sino que, de manera transversal, también se aborda desde un punto de vista inteligente aplicando metaheurísticas

    On Managing Knowledge for MAPE-K Loops in Self-Adaptive Robotics Using a Graph-Based Runtime Model

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    Service robotics involves the design of robots that work in a dynamic and very open environment, usually shared with people. In this scenario, it is very difficult for decision-making processes to be completely closed at design time, and it is necessary to define a certain variability that will be closed at runtime. MAPE-K (Monitor–Analyze–Plan–Execute over a shared Knowledge) loops are a very popular scheme to address this real-time self-adaptation. As stated in their own definition, they include monitoring, analysis, planning, and execution modules, which interact through a knowledge model. As the problems to be solved by the robot can be very complex, it may be necessary for several MAPE loops to coexist simultaneously in the robotic software architecture endowed in the robot. The loops will then need to be coordinated, for which they can use the knowledge model, a representation that will include information about the environment and the robot, but also about the actions being executed. This paper describes the use of a graph-based representation, the Deep State Representation (DSR), as the knowledge component of the MAPE-K scheme applied in robotics. The DSR manages perceptions and actions, and allows for inter- and intra-coordination of MAPE-K loops. The graph is updated at runtime, representing symbolic and geometric information. The scheme has been successfully applied in a retail intralogistics scenario, where a pallet truck robot has to manage roll containers for satisfying requests from human pickers working in the warehousePartial funding for open access charge: Universidad de Málaga. This work has been partially developed within SA3IR (an experiment funded by EU H2020 ESMERA Project under Grant Agreement 780265), the project RTI2018-099522-B-C4X, funded by the Gobierno de España and FEDER funds, and the B1-2021_26 project, funded by the University of Málaga

    Integration of the Alexa assistant as a voice interface for robotics platforms

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    Virtual assistants such as Cortana or Google Assistant are becoming familiar devices in everyday environments, where they are used to control real devices through natural language. This paper extends this application scenario, and it describes the use of the Alexa assistant from Amazon through an Echo dot device to drive the behaviour of a robotic platform. The paper focuses on the description of the technologies employed to set such ecosystem. Significantly, the proposed architecture is based, from the remote server to the on-board controllers, in LowEnergy (LE) hardware and a scalable software platform. This approach will ease programmers integrating different platforms, e.g. mobile-based applications to control robots or home-made devices.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Salmonella in free-living exotic and native turtles and in pet exotic turtles from SW Spain

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    We screened 78 native and 94 exotic turtles from natural ponds and 39 exotic pet turtles for presence of Salmonella, resulting with infection rates of 6.61%, 6.4%, and 5.1%, respectively. Concurrent shedding of multiple serotypes of the bacteria was only detected in one pet turtle. Eleven isolates were obtained in free-living turtles, including serotypes commonly found in reptiles and also the serotype Typhimurium, which is commonly related to human infections. In pet turtles, the five serotypes isolated were different to those isolated in free-living turtles and had been reported to cause reptile-associated salmonellosis in humans. These results confirm the risk of transmission of Salmonella from free-living and pet turtles to humans, demanding the necessity of regulation of pet turtle trade in Europe. © 2008 Elsevier Ltd. All rights reserved.Peer Reviewe

    Helminth communities of the exotic introduced turtle, Trachemys scripta elegans in southwestern Spain: Transmission from native turtles

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    We report the prevalence and diversity of helminth parasites found in native turtles Mauremys leprosa and Emys orbicularis from three localities in southwestern Spain and we describe the helminth communities of exotic turtles Trachemys scripta elegans coexisting in the wild with both native turtle species. Five nematodes species were identified, of which Serpinema microcephalus was the only species common between two localities, although infection parameters were different between them. This is the first report of cross transmission of S. microcephalus and Falcaustra donanaensis from native to exotic turtles and the first report of genus Physaloptera in turtles of the Palearctic Region. Continuous releasing of exotic pet turtles in wildlife ecosystems increases the risk of parasite introductions and, consequently, potential transmission to native species, and highlights the impending need for regulation of pet turtle trade in Europe

    Deposition of spray droplets by four spray nozzles and two working pressures

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    The deposition of spray droplets on the target can be influenced by the type spray nozzle used, as well as the employed working pressure. Thus, with the commercial availability of new spray nozzles, performance studies with the new models become necessary. This study was carried out to evaluate ground deposition of spray droplets by four models of spray nozzles, at two working pressures. The experiment was conducted in Dourados/MS, in September 2020, with strip design and 4x2 factorial scheme, with five repetitions. Four spray nozzles were used (single flat fan, ST-IA 02 model; angle flat fan MUG 02; hollow cone MGA 02; and double flat fan ST-IA/D 02), working at 30 and 50 psi pressures. The distance between each nozzle was 50 cm, 60 cm above the ground. Water-sensitive paper was used and, immediately after application, the paper was scanned using the DropScan® tool. Subsequently, the number of droplets, coverage, amplitude, dispersion,      Volume Median Diameter (VMD), Number Median Diameter (NMD), DV09, and DV01 were evaluated. The hollow cone spray nozzle provided a higher number of droplets and greater coverage compared to the other nozzles for the studied weather conditions

    A nanostructural view of the cell wall disassembly process during fruit ripening and postharvest storage by atomic force microscopy

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    Background: The mechanical properties of parenchyma cell walls and the strength and extension of adhesion areas between adjacent cells, jointly with cell turgor, are main determinants of firmness of fleshy fruits. These traits are modified during ripening leading to fruit softening. Cell wall modifications involve the depolymerisation of matrix glycans and pectins, the solubilisation of pectins and the loss of neutral sugars from pectin side chains. These changes weaken the cell walls and increase cell separation, which in combination with a reduction in cell turgor, bring about textural changes. Atomic force microscopy (AFM) has been used to characterize the nanostructure of cell wall polysaccharides during the ripening and postharvest storage of several fruits. This technique allows the imaging of individual polymers at high magnification with minimal sample preparation. Scope and approach: This paper reviews the main features of the cell wall disassembly process associated to fruit softening from a nanostructural point of view, as has been provided by AFM studies. Key findings and conclusions: AFM studies show that pectin size, ramification and complexity is reduced during fruit ripening and storage, and in most cases these changes correlate with softening. Postharvest treatments that improve fruit quality have been proven to preserve pectin structure, suggesting a clear link between softening and pectin metabolism. Nanostructural characterization of cellulose and hemicellulose during ripening has been poorly explored by AFM and the scarce results available are not conclusive. Globally, AFM could be a powerful tool to gain insights about the bases of textural fruit quality in fresh and stored fruits
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