450 research outputs found

    Micro Aerial Vehicles (MAV) Assured Navigation in Search and Rescue Missions Robust Localization, Mapping and Detection

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    This Master's Thesis describes the developments on robust localization, mapping and detection algorithms for Micro Aerial Vehicles (MAVs). The localization method proposes a seamless indoor-outdoor multi-sensor architecture. This algorithm is capable of using all or a subset of its sensor inputs to determine a platform's position, velocity and attitude (PVA). It relies on the Inertial Measurement Unit as the core sensor and monitors the status and observability of the secondary sensors to select the most optimum estimator strategy for each situation. Furthermore, it ensures a smooth transition between filters structures. This document also describes the integration mechanism for a set of common sensors such as GNSS receivers, laser scanners and stereo and mono cameras. The mapping algorithm provides a fully automated fast aerial mapping pipeline. It speeds up the process by pre-selecting the images using the flight plan and the onboard localization. Furthermore, it relies on Structure from Motion (SfM) techniques to produce an optimized 3D reconstruction of camera locations and sparse scene geometry. These outputs are used to compute the perspective transformations that project the raw images on the ground and produce a geo-referenced map. Finally, these maps are fused with other domains in a collaborative UGV and UAV mapping algorithms. The real-time aerial detection of victims is based on a thermal camera. The algorithm is composed by three steps. Firstly, a normalization of the image is performed to get rid of the background and to extract the regions of interest. Later the victim detection and tracking steps produce the real-time geo-referenced locations of the detections. The thesis also proposes the concept of a MAV Copilot, a payload composed by a set of sensors and algorithm the enhances the capabilities of any commercial MAV. To develop and validate these contributions, a prototype of a search and rescue MAV and the Copilot has been developed. These developments have been validated in three large-scale demonstrations of search and rescue operations in the context of the European project ICARUS: a shipwreck in Lisbon (Portugal), an earthquake in Marche (Belgium), and the Fukushima nuclear disaster in the euRathlon 2015 competition in Piombino (Italy)

    The MoMA and the promotion of modern furniture: Low-Cost Furniture Design Competition, 1948-1950

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    [EN] In 1941 Eero Saarinen and Charles Eames won First Prize in the competition of modern furniture sponsored by the MoMA. Although their designs of plywood chairs and armchairs were highly acclaimed by specialized critics, the USA entering the World War II hampered the later development of the awarded prototypes and scale models. The Museum launched again a competition in 1947, now aiming to promote furniture suitable for the new home life at post-war time. The 1950 exhibition of both the awarded prototypes and others of exceptional quality had significant repercussion on the design of furniture in 1950s, thus contributing to the imagery of what we know as the American Way of Life.[ES] En 1941 Eero Saarinen y Charles Eames ganaron los primeros premios en el concurso de mobiliario moderno promovido por el MoMA. Sus diseños de sillas y butacas de madera laminada fueron aclamados por la crítica especializada; sin embargo, la entrada de los Estado Unidos en la Segunda Guerra Mundial impidió el posterior desarrollo de los prototipos y modelos a escala premiados. En 1947 el Museo volvió a convocar un nuevo concurso, orientado en esta ocasión a promover un mobiliario adecuado a las nuevas condiciones de la vida doméstica en la época de posguerra. La exposición en 1950 de los prototipos premiados, junto a otros de calidad indudable, tendr´ía una gran repercusión en el diseño de mobiliario durante la década de los cincuenta, contribuyendo a forjar el imaginario de lo que solemos conocer como el American Way of Life.Montes Serrano, C.; Lafuente Sánchez, V.; López Bragado, D. (2022). El MoMA y la promoción del mobiliario moderno: Low-Cost Furniture Design Competition, 1948-1950. EGA Expresión Gráfica Arquitectónica. 27(46):172-183. https://doi.org/10.4995/ega.2022.18725172183274

    Elite coaches’ approach to quantifying technical actions and relative participation in volleyball players’ performance

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    This study sought to identify elite coaches’ perception of the importance of technical actions and the consideration of relative participation to measure individual volleyball players’ performance. An instrument was elaborated to gather the opinions of elite coaches on the importance of technical actions reported by the data volley (excluding setting), as well as considering relative participation. Twenty elite coaches with at least three years of experience in national teams or top leagues participated in the study. Variables considered in the study were analysed using descriptive statistics and reliability was measured with Cronbach’s α and McDonald’s Omega coefficients (> .70). The results assessed the importance of scoring actions, which received values of (1 point). All errors (terminal and continuity) were scored with (−1). Non-scoring actions were given values [.00, .80], except for poor attack (−.35), poor serve (−.60), free freeball (−.60) and reception free (−.50). Relative participation was considered according to the percentage of points and/or contacts played by each athlete. We concluded that for the player’s points and/or contacts, priority is given to actions that win points directly or are excellent, followed by those that contribute to building comfortable attacks, while penalising errors

    A Study on the Parametric Design Parameters That Influence Environmental Ergonomics and Sustainability

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    The parametric design applied to the built environment is critical to creating sustainable and resilient spaces. However, this research field involves a vast and complex amount of disconnected information. Therefore, this paper aims to analyse research trends in applying parametric design to optimise sustainability and environmental ergonomics parameters in built environments. The following specific objectives are identified to meet this objective: (i) a quantitative analysis based on a systematic literature review; (ii) a qualitative review based on a performance analysis and scientific mapping; and (iii) a comparative analysis of case studies applying parametric language for the optimisation of sustainability and environmental ergonomics parameters. The 1045 research records covering 1974 to 2021 illustrate a field in development that evolves from early digital advances to climate change adaptations, the circular economy and resilience. It highlights the importance of applying bioclimatic techniques in the built environment, identifying the most optimised measures and encouraging the creation of guidelines to serve as a protocol for future studies, contributing to the existing body of knowledge by highlighting trends, establishing research themes, outlining research networks and suggesting areas for further studiesPartial funding for open access charge: Universidad de Málag

    Transient Analysis of Fresnel Zone Plates for Ultrasound Focusing Applications

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    [EN] Fresnel Zone Plates are planar lenses that can be used to focus ultrasound beams. This kind of acoustic lenses can play a key role in the resolution of ultrasonic NDT systems. In this type of pulse-echo applications, the pulse duration is an important parameter that specifies the axial resolution, and thus, shorter ultrasound pulses provide higher resolutions. However, acoustic lenses exhibit a transient response that should be considered when setting the pulse duration, as pulses shorter than the transient state duration result in degradation in the response of acoustic lenses in terms of focal intensity, focal displacement, and lateral and axial resolutions. In this work, a thorough analysis of the transient response of Fresnel Zone Plates is discussed, demonstrating that the transient state should be considered in order to achieve optimal focusing performance. Theoretical and numerical results are presented, showing very good agreement.This work has been supported by Spanish MICINN RTI2018-100792-B-I00 project, Generalitat Valenciana AICO/2020/139 and the Russian Governmental program "Science" project FSWW-2020-0014. The research is carried out within the framework of Tomsk Polytechnic University Competitiveness Enhancement Program grant VIU-MNOL NK 187/2020. S.P.-L. acknowledges financial support from Universitat Politècnica de València grant program PAID-01-18. D.T.-S. acknowledges financial support from MICINN BES-2016-07713 project.Pérez-López, S.; Tarrazó-Serrano, D.; Dolmatov, DO.; Rubio Michavila, C.; Candelas Valiente, P. (2020). Transient Analysis of Fresnel Zone Plates for Ultrasound Focusing Applications. Sensors. 20(23):1-9. https://doi.org/10.3390/s20236824S192023Albu, S., Joyce, E., Paniwnyk, L., Lorimer, J. P., & Mason, T. J. (2004). Potential for the use of ultrasound in the extraction of antioxidants from Rosmarinus officinalis for the food and pharmaceutical industry. Ultrasonics Sonochemistry, 11(3-4), 261-265. doi:10.1016/j.ultsonch.2004.01.015Li, J.-T., Han, J.-F., Yang, J.-H., & Li, T.-S. (2003). An efficient synthesis of 3,4-dihydropyrimidin-2-ones catalyzed by NH2SO3H under ultrasound irradiation. Ultrasonics Sonochemistry, 10(3), 119-122. doi:10.1016/s1350-4177(03)00092-0McCann, D. ., & Forde, M. . (2001). Review of NDT methods in the assessment of concrete and masonry structures. NDT & E International, 34(2), 71-84. doi:10.1016/s0963-8695(00)00032-3Chen, J., Xiao, J., Lisevych, D., Shakouri, A., & Fan, Z. (2018). Deep-subwavelength control of acoustic waves in an ultra-compact metasurface lens. Nature Communications, 9(1). doi:10.1038/s41467-018-07315-6Thomas, J.-L., & Fink, M. A. (1996). Ultrasonic beam focusing through tissue inhomogeneities with a time reversal mirror: application to transskull therapy. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 43(6), 1122-1129. doi:10.1109/58.542055Melde, K., Mark, A. G., Qiu, T., & Fischer, P. (2016). Holograms for acoustics. Nature, 537(7621), 518-522. doi:10.1038/nature19755Castiñeira-Ibáñez, S., Tarrazó-Serrano, D., Fuster, J., Candelas, P., & Rubio, C. (2018). Polyadic Cantor Fractal Ultrasonic Lenses: Design and Characterization. Applied Sciences, 8(8), 1389. doi:10.3390/app8081389Rubio, C., Fuster, J., Castiñeira-Ibáñez, S., Uris, A., Belmar, F., & Candelas, P. (2017). Pinhole Zone Plate Lens for Ultrasound Focusing. Sensors, 17(7), 1690. doi:10.3390/s17071690Zhou, Q., Xu, Z., & Liu, X. (2019). High efficiency acoustic Fresnel lens. Journal of Physics D: Applied Physics, 53(6), 065302. doi:10.1088/1361-6463/ab5878Schindel, D. W., Bashford, A. G., & Hutchins, D. A. (1997). Focussing of ultrasonic waves in air using a micromachined Fresnel zone-plate. Ultrasonics, 35(4), 275-285. doi:10.1016/s0041-624x(97)00011-5Calvo, D. C., Thangawng, A. L., Nicholas, M., & Layman, C. N. (2015). Thin Fresnel zone plate lenses for focusing underwater sound. Applied Physics Letters, 107(1), 014103. doi:10.1063/1.4926607Tarrazó-Serrano, D., Pérez-López, S., Candelas, P., Uris, A., & Rubio, C. (2019). Acoustic Focusing Enhancement In Fresnel Zone Plate Lenses. Scientific Reports, 9(1). doi:10.1038/s41598-019-43495-xSalazar, J., Turó, A., Chávez, J. A., Ortega, J. A., & García, M. J. (2000). Transducer resolution enhancement by combining different excitation pulses. Ultrasonics, 38(1-8), 145-150. doi:10.1016/s0041-624x(99)00177-8Salazar, J., Turo, A., Chavez, J. A., Ortega, J. A., & Garcia, M. J. (2003). High-power high-resolution pulser for air-coupled ultrasonic nde applications. IEEE Transactions on Instrumentation and Measurement, 52(6), 1792-1798. doi:10.1109/tim.2003.820445Oelze, M. (2007). Bandwidth and resolution enhancement through pulse compression. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 54(4), 768-781. doi:10.1109/tuffc.2007.310Konovalov, S. I., & Kuz’menko, A. G. (2015). On the optimization of the shapes of short-duration acoustic pulses for solving probing problems in immersion tests. Russian Journal of Nondestructive Testing, 51(2), 101-107. doi:10.1134/s106183091502005

    AgSn[Bi1−xSbx]Se3: Synthesis, Structural Characterization, and Electrical Behavior

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    Herein, we report the synthesis, characterization, and electrical properties of lead-free AgSnm[Bi1−xSbx]Se2+m (m = 1, 2) selenides. Powder X-ray diffraction patterns and Rietveld refinement data revealed that these selenides consisted of phases related to NaCl-type crystal structure. The microstructures and morphologies of the selenides were investigated by backscattered scanning electron microscopy, energy-dispersive X-ray spectroscopy, and high-resolution transmission electron microscopy. The studied AgSnm[Bi1−xSbx]Se2+m systems exhibited typical p-type semiconductor behavior with a carrier concentration of approximately ~+1020 cm−3. The electrical conductivity of AgSnm[Bi1−xSbx]Se2+m decreased from ~3.0 to ~10−3 S·cm−1 at room temperature (RT) with an increase in m from 1 to 2, and the Seebeck coefficient increased almost linearly with increasing temperature. Furthermore, the Seebeck coefficient of AgSn[Bi1−xSbx]Se3 increased from ~+36 to +50 μV·K−1 with increasing Sb content (x) at RT, while its average value determined for AgSn2[Bi1−xSbx]Se4 was approximately ~+4.5 μV·K−1.Depto. de Química InorgánicaFac. de Ciencias QuímicasTRUEpu

    Equipamientos deportivos para el tenis: tecnología, construcción y sostenibilidad

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    Las personas, la sociedad y las distintas relaciones que se generan entre ellos y los elementos que los rodean, son los grandes impulsores de los cambios en la actualidad. La arquitectura, por tanto, deber ser la mejor herramienta para dar respuesta a todas las necesidades de esta sociedad. El trabajo fija su atención en tres elementos muy claros de la arquitectura y que afectan, en mayor o menor medida, al resultado final del edificio o equipamiento en cuestión. La tecnología ha evolucionado a pasos agigantados en las últimas décadas. Este continuo avance ha permitido generar nuevos materiales, nuevos acabados y nuevos procesos, es decir, una nueva manera de entender la construcción y todas las técnicas que la rodean. Además, todos estos adelantos abren nuevas oportunidades para implementar y garantizar los temas sostenibles, tan de actualidad, dentro de las intervenciones. La tecnología es, finalmente, el nexo común entre las diferentes partes del trabajo. Todas estas cuestiones tienen un impacto directo en los nuevos equipamientos. Concretamente en los que competen al tenis, han provocado un cambio radical en las instalaciones. Así pues, la arquitectura aprovecha los avances para crear: nuevas cubiertas, más ligeras y capaces de salvar mayores luces; unas superficies de juego más desarrolladas, y que mantienen sus características con independencia de factores externos; y unos graderíos más eficientes, tanto estructuralmente como garantizando la comodidad de los espectadores. La Caja Mágica de Dominique Perrault eleva exponencialmente todos los elementos y evoluciones antes mencionados. El estudio sobre lo constructivo y los materiales culmina con esta obra del arquitecto francés en Madrid. Perrault se ayuda de la tecnología para dar soluciones a todos los problemas que surgen durante el diseño

    Diásporas y transiciones en la Teoría del Actor-Red

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    Este texto es una presentación del monográfico Diásporas y transiciones en la teoría del actor-red. Sus páginas presentan las principales características de esta teoría, una manera de entender sus orígenes y una descripción de su presente estableciendo un paralelismo con la etnometodología. El texto finaliza con una valoración del estado de la teoría del actor-red en España y un comentario sobre un congreso que llevó el título de Presente y futuro de la teoría del actor-red y que constituye el embrión del presente monográfico. En el texto se defiende una tesis muy simple: la teoría del actor-red nace con cierta relevancia para el pensamiento social en el momento en que se difracta en una miríada de usos y aplicaciones diferentes. El principal corolario de este hecho también es muy sencillo: la gran diferencia entre la teoría del actor-red y otras propuestas del pensamiento social es su permanente estado de diáspora y transiciónThis paper is an introduction to the monograph titled Diasporas and Transitions in the Actor-Network Theory. Drawing a parallel with ethnomethodology, its pages present the main features of this theory, a way to figure out its origins and a description of its present. The text ends with a brief look at the state of art of actor-network theory in Spain and an appraisal of a meeting titled Present and Future of Actor-Network Theory, which is the origin of our monograph. In this paper we put forward a very simple idea: Actor-Network Theory was born with certain relevance in Social Sciences when it diffracted in a myriad of different uses and applications. The main corollary of such an idea is also straightforward: the very difference between Actor- Network Theory and other perspectives in Social Sciences resides in the permanent diaspora and transition of the forme
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