Encontrado(s) 2240544 resultado(s)
Encontrada(s) 224055 página(s)

Presentació, Presentación

  • Olivé Ramon, Antoni

Proposta d'horts escolars ecològics al nou parc forestal de Cervelló

  • Bescós I Yañez, Claudia
The Cervelló forest is a large area of uniform vegetation that has not developed properly due to the abandonment of many agricultural plots, which has left only the remnants of what was once a fully functioning agro-forestry mosaic. The aim of this proposal is to design an ecological school garden, situated in the new Cervelló Forest Park, as a model for managing vegetation by means of clearings. In addition, it aims to change the approach to teaching in the local schools. The proposal, which is explained below, reviews each aspect that should be addressed to carry out the transformation of the plot in an effective way. The document is separated into three main sections: the first section, in which the area of intervention is described; the second section, in which the basis of the proposal is explained, and the final section, in which the proposal is developed., El bosque de Cervelló se ha convertido en una gran mancha de vegetación uniforme que no madura adecuadamente. El abandono de muchas parcelas agrícolas ha dejado los vestigios del que un día fue un mosaico agro-forestal en pleno funcionamiento. Ésta propuesta tiene por objetivo el diseño de un huerto escolar ecológico, situado en el nuevo Parque Forestal de Cervelló, como modelo de gestión de la vegetación mediante claros. Además, pretende ser una herramienta de cambio en el planteamiento de la enseñanza de las escuelas de la población. La propuesta, que se explica a continuación, repasa cada uno de los aspectos que deberían adaptarse para realizar la transformación de la parcela de forma satisfactoria. El documento está separado en tres grandes bloques: un primer bloque, en el que se describe el área de intervención; un segundo punto, donde se asientan las bases de la propuesta, explicando la situación de partida. I por último, un apartado en el que se desarrolla la propuesta., El bosc de Cervelló ha esdevingut una gran taca de vegetació uniforme que no madura adequadament. L’abandonament de moltes parcel·les agrícoles ha deixat els vestigis del que un dia va ser un mosaic agro-forestal en ple funcionament. Aquesta proposta té per objectiu el disseny d’un hort escolar ecològic, situat al nou Parc Forestal de Cervelló, com a model de gestió de la vegetació mitjançant clarianes. A més, pretén ser una eina de canvi en el plantejament de l’ensenyança a les escoles de la població. La proposta, que s’explica a continuació, repassa cadascun dels aspectes que s’haurien d’adaptar per tal de realitzar la transformació de la parcel·la de forma satisfactòria. El document està separat en tres grans blocs: un primer, en el que es descriu l’àrea d’intervenció; un segon punt, en el que es posen les bases de la proposta, explicant la situació de partida. I per últim, un apartat en el que es desenvolupa la proposta.

Efficiency analysis of wide band-gap semiconductors for two-level and three-level power converters

  • Lumbreras Carrasco, David
  • Zaragoza Bertomeu, Jordi
  • Mon González, Juan
  • Gálvez, Eduardo
  • Collado Escolano, Alfonso
© 2019 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., Power devices based on wide band-gap materials are emerging as alternatives to silicon-based devices. These new devices allow designing and building converters with fewer power losses, and are thus more highly efficient than traditional power converters. Among the wide band-gap materials in use, silicon carbide (SiC) and gallium nitride (GaN) devices are the most promising because of their excellent properties and commercial availability. This paper compares the losses produced in two-level and three-level power converters that use the aforementioned technologies. In addition, we assess the impact on the converter performance caused by the modulation technique. Simulation results under various operating points are reported and compared., Peer Reviewed

Cultural configuration of Wikipedia: measuring autoreferentiality in different languages

  • Miquel Ribé, Marc
  • Rodríguez Hontoria, Horacio
Among the motivations to write in Wikipedia given by the current literature there is often coincidence, but none of the studies presents the hypothesis of contributing for the visibility of the own national or language related content. Similar to topical coverage studies, we outline a method which allows collecting the articles of this content, to later analyse them in several dimensions. To prove its universality, the tests are repeated for up to twenty language editions of Wikipedia. Finally, through the best indicators from each dimension we obtain an index which represents the degree of autoreferentiality of the encyclopedia. Last, we point out the impact of this fact and the risk of not considering its existence in the design of applications based on user generated content.

Pareto optimal reconfiguration of power distribution systems using a genetic algorithm based on NSGA-II

  • Tomoiaga, Bogdan
  • Chindris, Mircea
  • Sumper, Andreas
  • Sudrià Andreu, Antoni
  • Villafafila Robles, Roberto
Reconfiguration, by exchanging the functional links between the elements of the system, represents one of the most important measures which can improve the operational performance of a distribution system. The authors propose an original method, aiming at achieving such optimization through the reconfiguration of distribution systems taking into account various criteria in a flexible and robust approach. The novelty of the method consists in: the criteria for optimization are evaluated on active power distribution systems (containing distributed generators connected directly to the main distribution system and microgrids operated in grid-connected mode); the original formulation (Pareto optimality) of the optimization problem and an original genetic algorithm (based on NSGA-II) to solve the problem in a non-prohibitive execution time. The comparative tests performed on test systems have demonstrated the accuracy and promptness of the proposed algorithm.

Buscador avanzado