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Search Results: 1 - 10 of 216343 matches for " Sebastián Rodríguez "
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Neural Network for Estimating Daily Global Solar Radiation Using Temperature, Humidity and Pressure as Unique Climatic Input Variables  [PDF]
Victor Adrian Jimenez, Amelia Barrionuevo, Adrian Will, Sebastián Rodríguez
Smart Grid and Renewable Energy (SGRE) , 2016, DOI: 10.4236/sgre.2016.73006
Abstract: Solar radiation is one of the most important parameters for applications, development and research related to renewable energy. However, solar radiation measurements are not a simple task for several reasons. In the cases where data are not available, it is very common the use of computational models to estimate the missing data, which are based mainly on the search for relationships between weather variables, such as temperature, humidity, precipitation, cloudiness, sunshine hours, etc. But, many of these are subjective and difficult to measure, and thus they are not always available. In this paper, we propose a method for estimating daily global solar radiation, combining empirical models and artificial neural networks. The model uses temperature, relative humidity and atmospheric pressure as the only climatic input variables. Also, this method is compared with linear regression to verify that the data have nonlinear components. The models are adjusted and validated using data from five meteorological stations in the province of Tucumán, Argentina. Results show that neural networks have better accuracy than empirical models and linear regression, obtaining on average, an error of 2.83 [MJ/m2] in the validation dataset.
Adjustment of Model Parameters to Estimate Distribution Transformers Remaining Lifespan  [PDF]
Victor A. Jimenez, Adrian Will, Jorge Gotay, Sebastián Rodríguez
Smart Grid and Renewable Energy (SGRE) , 2018, DOI: 10.4236/sgre.2018.99010
Abstract: Currently, the electrical system in Argentina is working at its maximum capacity, decreasing the margin between the installed power and demanded consumption, and drastically reducing the service life of transformer substations due to overload (since the margin for summer peaks is small). The advent of the Smart Grids allows electricity distribution companies to apply data analysis techniques to manage resources more efficiently at different levels (avoiding damages, better contingency management, maintenance planning, etc.). The Smart Grids in Argentina progresses slowly due to the high costs involved. In this context, the estimation of the lifespan reduction of distribution transformers is a key tool to efficiently manage human and material resources, maximizing the lifetime of this equipment. Despite the current state of the smart grids, the electricity distribution companies can implement it using the available data. Thermal models provide guidelines for lifespan estimation, but the adjustment to particular conditions, brands, or material quality is done by adjusting parameters. In this work we propose a method to adjust the parameters of a thermal model using Genetic Algorithms, comparing the estimation values of top-oil temperature with measurements from 315 kVA distribution transformers, located in the province of Tucumán, Argentina. The results show that, despite limited data availability, the adjusted model is suitable to implement a transformer monitoring system.
Llicenciat en psicopedagogia. Un títol polèmic
Sebastián Rodríguez Espinar
Temps d'Educació , 1993,
Abstract:
Presentació
Sebastián Rodríguez Espinar
Temps d'Educació , 1992,
Abstract:
La qualitat de l'educació en el Projecte per a la Reforma de l'Ensenyament
Sebastián Rodríguez Espinar
Temps d'Educació , 1989,
Abstract: La définition du profil de la qualité du "produit" issu des institutions éducatives constitue un des objectifs fondamentaux de tout project de reforme éducative. Cependant, la difficulté posée par un tel objectif fait que la question de la qualité de I'éducation soit, malgré la séduction politique qu'elle exerce, objet d'imprecisions dues a I'absence d'univocité de ce concept et de la tentative politique d'éluder un engagement idéologique. Cette étude anaIyse différentes conceptualisations de la qualité de I'éducation et défend la nécessité de préciser et cerner le concept de produit éducatif. Ensuite, elle examine les indicateurs de qualité explicités dans le Proyecto de Reforma de la Ense anza, par rapport aux objectifs généraux de chacune des étapes éducatives. Cette anaIyse dévoile une conception imprécise et mutilée de la qualité de I'éducation. Defining the profile and quality of the "outpur of institutions is one of the main goals of any educational reform project. However, the difficulty posed by such an objective makes the issue of the quality of education, in spite of its political attractiveness, an object of imprecision as a result of the lack of singlemindedness regarding it and the political attempt to evade an ideological commitment. This article looks at different conceptualizations of the quality of education and defends the need to state clearIy and delimit the concept of educational output. Then it examines the quality indicators contained in the Educational Reform Project in the light of the general goals for each educational stage. Out of this analysis comes an imprecise, mutilated conception of the quality of education. Definir el perfil y calidad del ·producto· egresado de las instituciones constituye uno de los objetivos básicos de cualquier proyecto de reforma educativa. Sin embargo, la dificultad que plantea tal objetivo hace que el tema de la calidad de la educación, pese a su atracción política, sea objeto de imprecisiones como consecuencia de la falta de univocidad en el mismo y del intento político de soslayar un compromiso ideológico. En este trabajo se analizan diferentes conceptualizaciones de la calidad de la educación, defendiéndose la necesidad de precisar y acotar el concepto de calidad que se explicitan en el Proyecto de Reforma de la Ense anza a la luz de los objetivos generales para cada una de las etapas educativas. De dicho análisis se deriva una imprecisa y mutilada concepción de calidad de la educación.
L'avaluació universitària: l'experiència de la Universitat de Barcelona
Sebastián Rodríguez Espinar
Temps d'Educació , 1992,
Abstract:
Evaluación comprensiva del profesorado universitario
Sebastián Rodríguez Espinar
Educación Médica , 2003,
Abstract:
Mediciones de rompimiento electrostático en separaciones micrométricas
Rodríguez,Juan Sebastián; Bonilla,Sebastián; ávila,Alba;
Revista de Ingeniería , 2009,
Abstract: the continuous miniaturization of electronic and electromechanical devices has allowed the study of non-visible effects on macroscales, as it is the case of the behavior of microgap separated electrodes. the behavior of aluminum electrodes at atmospheric pressure appears here for a rank of separations of 1 μm to 22 μm. the paschen curve is conventionally used to describe the behavior of electrodes. the results demonstrate that at separations smaller than 4 μm the breakdown voltage in the electrodes decays dramatically and it does not present a minimum as predicts the paschen curve. this modification establishes critical conditions of operation in devices based on electrodes with microgap separations [1, 2].
Mediciones de rompimiento electrostático en separaciones micrométricas
Juan Sebastián Rodríguez,Sebastián Bonilla,Alba ávila
Revista de Ingeniería , 2009,
Abstract: La continua miniaturización de dispositivos electrónicos y electro-mecánicos ha permitido el estudio de efectos no visibles a macroescalas, como es el caso del comportamiento de electrodos separados a microescala. Se presenta aquí el comportamiento de electrodos de aluminio a presión atmosférica para un rango de separaciones de 1 mm a 22 mm. Convencionalmente, el comportamiento de electrodos se describe a partir de la curva de Paschen. Los resultados demuestran que, a separaciones menores de 4 mm, el voltaje de rompimiento en los electrodos decae drásticamente y no presenta un mínimo como lo predice la curva de Paschen. Esta modificación establece condiciones críticas de operación en dispositivos basados en electrodos con separaciones a microescalas./ The continuous miniaturization of electronic and electromechanical devices has allowed the study of non-visible effects on macroscales, as it is the case of the behavior of microgap separated electrodes. The behavior of aluminum electrodes at atmospheric pressure appears here for a rank of separations of 1 mm to 22 mm. The Paschen curve is conventionally used to describe the behavior of electrodes. The results demonstrate that at separations smaller than 4 mm the breakdown voltage in the electrodes decays dramatically and it does not present a minimum as predicts the Paschen curve. This modification establishes critical conditions of operation in devices based on electrodes with microgap separations.
Limpieza y desinfección: riesgo toxicológico Cleaning and disinfection: toxicological risk
Sebastián Sánchez-Fortún Rodríguez
Revista de Salud Ambiental , 2006,
Abstract: La utilización de biocidas para la desinfección de superficies, como las torres de refrigeración, ha llegado a ser un elemento clave para la prevención de enfermedades, como es el caso de la legionelosis. Pero su utilización conlleva asumir una serie de riesgos, tanto para la Salud Pública como para el entorno medioambiental donde las descargas procedentes de los puntos de aplicación pueden provocar profundas alteraciones en el medio acuático. El análisis efectuado en el presente trabajo, acerca de los diferentes parámetros para la evaluación del riesgo que supone la utilización de estos formulados, lleva a la conclusión de que, aún entendiendo que todo biocida podría provocar efectos no deseados sobre los seres vivos y el medioambiente, un correcto equilibrio entre los criterios de eficacia y seguridad es la única pauta viable para prevenir el riesgo toxicológico generado por las necesarias pautas de limpieza y desinfección de estas superficies. The use of biocides for the surfaces disinfection, as cooling towers, has ended up being a key element for the prevention of illnesses, like it is the case of legionelosis disease. But their use bears to assume risks, as much for the Public and Environmental Health where the discharges can cause deep alterations in the aquatic ecosystems. The analysis apply in this work, about the different parameters for the risk evaluation that supposes the use of these formulated, takes to the conclusion that, still understanding that all biocide could cause adverse effects on organisms and environments, a correct balance among effectiveness and security approaches is the only viable rule to prevent the toxicological risk generated by the necessary cleaning and disinfection rules of these surfaces.
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