2,824 research outputs found

    Optimal security-constrained power scheduling by Benders decomposition

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    This paper presents a Benders decomposition approach to determine the optimal day-ahead power scheduling in a pool-organized power system, taking into account dispatch, network and security constraints. The study model considers the daily market and the technical constraints resolution as two different and consecutive processes. The daily market is solved in a first stage subject to economical criteria exclusively and then, the constraints solution algorithm is applied to this initial dispatch through the redispatching method. The Benders partitioning algorithm is applied to this constraints solution process to obtain an optimal secure power scheduling. The constraints solution includes a full AC network and security model to incorporate voltages magnitudes as they are a critical factor in some real power systems. The algorithm determines the active power committed to each generator so as to minimize the energy redispatch cost subject to dispatch, network and security constraints. The solution also provides the reactive power output of the generators, the value of the transformers taps and the committed voltage control devices. The model has been tested in the IEEE 24-bus Reliability Test System and in an adapted IEEE 118-bus Test System. It is programmed in GAMS mathematical modeling language. Some relevant results are reported.Publicad

    Crystallization studies and application of innovative solid polymer electrolytes for lithium batteries

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    206 p.En esta tesis de doctorado se estudiaron diferentes sistemas de electrolitos poliméricos, con el objetivo de ser utilizados en baterías de litio. Los sistemas poliméricos desarrolados se prepararon con la finalidad de mejorar las prestaciones de los electrolitos sílidos actuales en términos de conductividad iónica, numero de transferencia de litio, propiedades mecánicas a elevada temperatura o resistencia a la llama. El polióxido de etileno (PEO) es el polímero mas utilizado en la actualidad como electrolito de polímero sólido en baterías de litio, ya que presenta los valores mas altos de conductividad iónica, pero tiene algunos parametros mejorables como su estabilidad térmica, electroquímica y propiedades mecánicas. En esta tesis, se utilizó PEO y se estudió el efecto sobre la cristalinidad del PEO la adición de sal de litio (LiTFSI) y diferentes polímeros.Los sistemas de electrolitos estudiados en esta tesis fueron preparados como mezcla de polímero y utilizando copolímeros de bloque

    Slide-Down Prevention for Wheeled Mobile Robots on Slopes

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    Wheeled mobile robots on inclined terrain can slide down due to loss of traction and gravity. This type of instability, which is different from tip-over, can provoke uncontrolled motion or get the vehicle stuck. This paper proposes slide-down prevention by real-time computation of a straightforward stability margin for a given ground-wheel friction coefficient. This margin is applied to the case study of Lazaro, a hybrid skid-steer mobile robot with caster-leg mechanism that allows tests with four or five wheel contact points. Experimental results for both ADAMS simulations and the actual vehicle demonstrate the effectiveness of the proposed approach.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Ground Extraction from 3D Lidar Point Clouds

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    © 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works Pomares, A., Martínez, J.L., Mandow, A., Martínez, M.A., Morán, M., Morales, J. Ground extraction from 3D lidar point clouds with the Classification Learner App (2018) 26th Mediterranean Conference on Control and Automation, Zadar, Croatia, June 2018, pp.400-405. DOI: PendingGround extraction from three-dimensional (3D) range data is a relevant problem for outdoor navigation of unmanned ground vehicles. Even if this problem has received attention with specific heuristics and segmentation approaches, identification of ground and non-ground points can benefit from state-of-the-art classification methods, such as those included in the Matlab Classification Learner App. This paper proposes a comparative study of the machine learning methods included in this tool in terms of training times as well as in their predictive performance. With this purpose, we have combined three suitable features for ground detection, which has been applied to an urban dataset with several labeled 3D point clouds. Most of the analyzed techniques achieve good classification results, but only a few offer low training and prediction times.This work was partially supported by the Spanish project DPI 2015- 65186-R. The publication has received support from Universidad de Málaga, Campus de Excelencia Andalucía Tech

    Performance Analysis of Synchronous Duty-Cycled MAC Protocols

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    © 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.In this letter, we propose an analytical model to evaluate the performance of the S-MAC protocol. The proposed model improves the accuracy of previous models in two aspects. First, it incorporates the dependence among the nodes within a cluster by defining a DTMC that models the number of active nodes, whereas the previous models considered that nodes were mutually independent. Second, it proposes new methods for calculating packet delay and energy consumption. The analytical model is validated through discrete-event based simulations. Numerical results demonstrate that the proposed analytical model and methods yield accurate results under realistic assumptionsThis work was supported in part by the Spanish Government through project TIN2013-47272-C2-1-R. The associate editor coordinating the review of this paper and approving it for publication was J.-C. Chen.Martínez Bauset, J.; Guntupalli, L.; Li, F. (2015). Performance Analysis of Synchronous Duty-Cycled MAC Protocols. IEEE Wireless Communications Letters. 4(5):469-472. https://doi.org/10.1109/LWC.2015.2439267S4694724

    obtención de barridos láser 3D nivelados conn el robot móvil Andábata en movimiento

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    Este artículo describe la adquisición de barridos tridimensionales (3D) nivelados en el robot móvil Andábata sin necesidad de detener su movimiento. Para ello, la computadora de Andábata debe integrar cada uno de los rangos láser, adquiridos con unos determinados ángulos de cabeceo y guiñada, con la información odométrica y las medidas de inclinación del vehículo para producir coordenadas Cartesianas niveladas referenciadas al inicio de cada barrido. Todo ello se ha realizado bajo el sistema operativo de robots ROS con la ayuda de paquetes estándard. El correcto funcionamiento de este esquema local de Localización y Modelado Simultáneos (SLAM) se ha comprobado experimentalmente sobre terreno inclinado.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Sistemas de documentación y elaboración de textos científicos: Una asignatura para aprender a publicar en ingeniería

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    Hoy en día, la elaboración y presentación de informes de investigación resulta indispensable para muchos profesionales de la ingeniería. En este artículo se describe una asignatura de máster universitario cuyo principal objetivo es proporcionar los conocimientos necesarios para poder escribir y exponer resultados de investigación en ingeniería mecatrónica. De esta manera, se complementa la formación de los ingenieros para que puedan desenvolverse con éxito en el complejo mundo de la investigación.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Construction and Calibration of a Low-Cost 3D Laser Scanner with 360â—¦ Field of View for Mobile Robots

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    Navigation of many mobile robots relies on environmental information obtained from three-dimensional (3D) laser scanners. This paper presents a new 360◦ field-of-view 3D laser scanner for mobile robots that avoids the high cost of commercial devices. The 3D scanner is based on spinning a Hokuyo UTM- 30LX-EX two-dimensional (2D) rangefinder around its optical center. The proposed design profits from lessons learned with the development of a previous 3D scanner with pitching motion. Intrinsic calibration of the new device has been performed to obtain both temporal and geometric parameters. The paper also shows the integration of the 3D device in the outdoor mobile robot Andabata.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Project-Based Learning of Scientific Writing and Communication Skills for Postgraduate Students

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    Mandow, A; Martínez, J. L.; García-Cerezo, A.; , "Project-Based Learning of Scientific Writing and Communication Skills for Postgraduate Students," IEEE Frontiers in Education Conference (FIE), pp.210-213, Oct. 2014 doi: 10.1109/FIE.2014.7044022This paper addresses education on scientific publication skills for post-graduate engineering students. In particular, a project-based learning strategy is proposed to lead students through the preparation a research paper. Expected learning outcomes are related to finding and evaluating the quality of references, editing and formatting text in \LaTeX, writing scientific papers with appropriate style and structure, peer reviewing, and making technical presentations. This approach has been developed to increase the internationalization and visibility of young researchers by improving the quality standards of their published works. The purpose of this innovative practice is that students confront the major challenges of the publication process in the classroom, which is in contrast with the traditional self-taught approach experienced by the authors and many senior researchers. The proposed strategy is being applied as a required course in the Master in Mechatronics Engineering of the University of Malaga. This paper offers preliminary results from this experience.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been partially supported by projects DPI 2011-22443 (Spanish CICYT) and PIE 13-155 (Universidad de Málaga, proyecto de innovación educativa `Aprendizaje basado en proyectos para mejorar la excelencia de publicaciones científicas y transferencia del conocimiento en ingeniería")

    Relationship between Corneal Morphogeometrical Properties and Biomechanical Parameters Derived from Dynamic Bidirectional Air Applanation Measurement Procedure in Keratoconus

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    The morphogeometric analysis of the corneal structure has become a clinically relevant diagnostic procedure in keratoconus (KC) as well as the in vivo evaluation of the corneal biomechanical properties. However, the relationship between these two types of metrics is still not well understood. The current study investigated the relationship of corneal morphogeometry and volume with two biomechanical parameters: corneal hysteresis (CH) and corneal resistance factor (CRF), both provided by an Ocular Response Analyzer (Reichert). It included 109 eyes from 109 patients (aged between 18 and 69 years) with a diagnosis of keratoconus (KC) who underwent a complete eye examination including a comprehensive corneal topographic analysis with the Sirius system (CSO). With the topographic information obtained, a morphogeometric and volumetric analysis was performed, defining different variables of clinical use. CH and CRF were found to be correlated with these variables, but this correlation was highly influenced by corneal thickness. This suggests that the mechanical properties of KC cornea contribute only in a partial and limited manner to these biomechanical parameters, being mostly influenced by morphogeometry under normal intraocular pressure levels. This would explain the limitation of CH and CRF as diagnostic tools for the detection of incipient cases of KC.This publication was carried out in the framework of the Thematic Network for Co-Operative Research in Health (RETICS) reference number RD12/0034/0007 and RD16/0008/0012, financed by the Carlos III Health Institute—General Subdirection of Networks and Cooperative Investigation Centers (R&D&I National Plan 2008–2011) and the European Regional Development Fund (FEDER). The author David P. Piñero has been supported by the Ministry of Economy, Industry, and Competitiveness of Spain within the program Ramón y Cajal, RYC-2016-20471
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