3,852 research outputs found

    Studying the capacity of cellular encoding to generate feedforward neural network topologies

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    Proceeding of: IEEE International Joint Conference on Neural Networks, IJCNN 2004, Budapest, 25-29 July 2004Many methods to codify artificial neural networks have been developed to avoid the disadvantages of direct encoding schema, improving the search into the solution's space. A method to analyse how the search space is covered and how are the movements along search process applying genetic operators is needed in order to evaluate the different encoding strategies for multilayer perceptrons (MLP). In this paper, the generative capacity, this is how the search space is covered for a indirect scheme based on cellular systems, is studied. The capacity of the methods to cover the search space (topologies of MLP space) is compared with the direct encoding scheme.Publicad

    Generative capacities of cellular automata codification for evolution of NN codification

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    Proceeding of: International Conference on Artificial Neural Networks. ICANN 2002, Madrid, Spain, August 28-30, 2002Automatic methods for designing artificial neural nets are desired to avoid the laborious and erratically human expert’s job. Evolutionary computation has been used as a search technique to find appropriate NN architectures. Direct and indirect encoding methods are used to codify the net architecture into the chromosome. A reformulation of an indirect encoding method, based on two bi-dimensional cellular automata, and its generative capacity are presented.Publicad

    Non-Direct Encoding Method Based on Cellular Automata to Design Neural Network Architectures

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    Architecture design is a fundamental step in the successful application of Feed forward Neural Networks. In most cases a large number of neural networks architectures suitable to solve a problem exist and the architecture design is, unfortunately, still a human expert’s job. It depends heavily on the expert and on a tedious trial-and-error process. In the last years, many works have been focused on automatic resolution of the design of neural network architectures. Most of the methods are based on evolutionary computation paradigms. Some of the designed methods are based on direct representations of the parameters of the network. These representations do not allow scalability; thus, for representing large architectures very large structures are required. More interesting alternatives are represented by indirect schemes. They codify a compact representation of the neural network. In this work, an indirect constructive encoding scheme is proposed. This scheme is based on cellular automata representations and is inspired by the idea that only a few seeds for the initial configuration of a cellular automaton can produce a wide variety of feed forward neural networks architectures. The cellular approach is experimentally validated in different domains and compared with a direct codification scheme.Publicad

    Evolutionary cellular configurations for designing feed-forward neural networks architectures

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    Proceeding of: 6th International Work-Conference on Artificial and Natural Neural Networks, IWANN 2001 Granada, Spain, June 13–15, 2001In the recent years, the interest to develop automatic methods to determine appropriate architectures of feed-forward neural networks has increased. Most of the methods are based on evolutionary computation paradigms. Some of the designed methods are based on direct representations of the parameters of the network. These representations do not allow scalability, so to represent large architectures, very large structures are required. An alternative more interesting are the indirect schemes. They codify a compact representation of the neural network. In this work, an indirect constructive encoding scheme is presented. This scheme is based on cellular automata representations in order to increase the scalability of the method

    Un artesonado poliédrico manierista en Castroverde de Campos (Zamora, España)

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    This paper analyses an outstanding case in the field of historic Spanish carpentry. Built in the sixteenth century, the fivepanel wood coffered ceiling in the church of Santa María del Río in Castroverde de Campos (Zamora, Spain) shows a Renaissance layout with polygonal coffers. It combines Hispano–Islamic technological heritage with some innovative features, including singular disposition of timber, duplicity of structures and unorthodox carpentry joints. Furthermore, convex coffers are introduced among traditional concave ones giving it a marked Mannerist appearance. The likely double role of the author as designer and contractor explains the relevance of prefabricated elements in the construction process of the ceiling, since this effort for modulation and systematization rationalizes procedures and reduces labour costs.Este artículo analiza un caso excepcional en la carpintería de armar en España. Se trata del artesonado de cinco paños de la iglesia de Santa María del Río, en Castroverde de Campos (Zamora). Construido en el s. XVI, con una trama de artesones poligonales en su intradós, combina el diseño renacentista con la tradición técnica hispano-musulmana de estructuras de madera, y presenta aportaciones novedosas como la inusual disposición de escuadrías, la duplicidad de estructuras y las poco ortodoxas uniones carpinteras utilizadas. Además, la introducción de artesones convexos junto a los convencionales artesones cóncavos le confiere un marcado aspecto manierista y resuelve ingeniosamente el encuentro entre paños. La muy posible coincidencia de diseñador y constructor en la misma persona explicaría un proceso de construcción con módulos prefabricados, con el consiguiente ahorro de costes y riesgos laborales

    Revealing patterns of local species richness along environmental gradients with a novel network tool

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    How species richness relates to environmental gradients at large extents is commonly investigatedaggregating local site data to coarser grains. However, such relationships often change with the grainof analysis, potentially hiding the local signal. Here we show that a novel network technique, the"method of reflections", could unveil the relationships between species richness and climate withoutsuch drawbacks. We introduced a new index related to potential species richness, which revealedlarge scale patterns by including at the local community level information about species distributionthroughout the dataset (i.e., the network). The method effectively removed noise, identifying howfar site richness was from potential. When applying it to study woody species richness patterns inSpain, we observed that annual precipitation and mean annual temperature explained large parts ofthe variance of the newly defined species richness, highlighting that, at the local scale, communitiesin drier and warmer areas were potentially the species richest. Our method went far beyond whatgeographical upscaling of the data could unfold, and the insights obtained strongly suggested that itis a powerful instrument to detect key factors underlying species richness patterns, and that it couldhave numerous applications in ecology and other fields.Comunidad de MadridMinisterio de Economía y Competitivida

    Methodology to assess the maximum irrigation rates at regional scale using geostatistics and GIS

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    Ponencia presentada en la Conference of Agricultural Engineering celebrada en Valencia del 8 añ 12 de julio de 2012Soil water holding capacity is an important parameter for irrigation scheduling and water balance modelling in fields. In the framework of precision irrigation the knowledge of the spatial distribution of this parameter is useful to advice the maximum irrigation rate specifically for each field in an irrigation district, region, etc. The soil water holding capacity (SWHC) can be assessed as the soil water content between the field capacity (FC) and the permanent wilting point (PWP). In this work, we present a methodology to assess the spatial distribution of the maximum irrigation rate depending on the soil water holding capacity. This methodology combines geostatistic techniques with geographical information system-GIS tool. A pilot zone of 12 400 ha located in the Palancia river lowland (between Valencia and Castellón province, Spain) in which the main irrigated crops are citrus (53.8 %), and vegetables (13.3 %), was selected to develop this methodology. For spatial modelling of SWHC, experimental semivariograms were assessed for the FC and PWP at three soil depth intervals (0-10, 10-30, 30-60 cm). Spherical models fitted well to the experimental semivariograms, with a very high spatial dependency index (ID = 0.05-0.41) which support reliable predictions on basis the fitted models. The cokriging spatial interpolation method, considering the percentage of sand as secondary variable, was the best option to minimize the root mean square error in the cross-validation test.Peer Reviewe

    The nature of the diffuse light near cities detected in nighttime satellite imagery

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    Open Access.-- This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Diffuse glow has been observed around brightly lit cities in nighttime satellite imagery since at least the first publication of large scale maps in the late 1990s. In the literature, this has often been assumed to be an error related to the sensor, and referred to as "blooming", presumably in relation to the effect that can occur when using a CCD to photograph a bright light source. Here we show that the effect seen on the DMSP/OLS, SNPP/VIIRS-DNB and ISS is not only instrumental, but in fact represents a real detection of light scattered by the atmosphere. Data from the Universidad Complutense Madrid sky brightness survey are compared to nighttime imagery from multiple sensors with differing spatial resolutions, and found to be strongly correlated. These results suggest that it should be possible for a future space-based imaging radiometer to monitor changes in the diffuse artificial skyglow of cities.© 2020, The Author(s).Tis work was supported by the EMISSI@N project (NERC grant NE/P01156X/1), COST (European Cooperation in Science and Technology) Action ES1204 LoNNe (Loss of the Night Network), the ORISON project (H2020- INFRASUPP-2015-2), the Cities at Night project, the European Union’s Horizon 2020 research and innovation programme under grant agreement no 689443 via project GEOEssential, FPU grant from the Ministerio de Ciencia y Tecnologia and F. Sánchez de Miguel. We acknowledge the support of the Spanish Network for Light Pollution Studies (MINECO AYA2011-15808-E) and also from STARS4ALL, a project funded by the European Union H2020-ICT-2015-688135. This work has been partially funded by the Spanish MICINN (AYA2016- 75808-R), and by the Madrid Regional Government through the TEC2SPACE-CM Project (P2018/NMT-4291). Te ISS images are courtesy of the Earth Science and Remote Sensing Unit, NASA Johnson Space Center. CCMK acknowledges the funding received through the European Union’s Horizon 2020 research and innovation programme ERA-PLANET, grant agreement no. 689443, via the GEOEssential project, and funding from the Helmholtz Association Initiative and Networking Fund under grant ERC-RA-0031. We thank J. Coesfeld for producing Fig. 1. We thank the organizers of the LPTMM 2013 conference for providing a stimulating forum in which we discussed the nature of the difuse light around cities in detail. Tanks to Emma R. Howard for her help in the editing of this article.Peer reviewe

    Cr3+ substituted Zn-Al layered double hydroxides as UV–Vis light photocatalysts for NO gas removal from the urban environment

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    The ZnAl-CO3, ZnAlCr-CO3 and ZnCr-CO3 LDH samples were studied as De-NOx photocatalysts in this work. Samples without Cr and increasing the presence of Cr3+ in the LDH framework in the 0.06, 0.15 and 0.3 Cr/Zn ratio were prepared by co-precipitation method, all of them constituted by pure LDH phase. The increase of chromium content in the LDH framework leads to lower crystallinity and higher specific surface area in the samples. Moreover, the CrO6 octahedron centres expand the photo-activity from UV to Visible light and assist to decrease the recombination rate of the electrons and holes. The favourable textural, optical and electronic properties of Cr-containing LDH samples explain the good NO removal efficiency (55%) and outstanding selectivity (90%) found for the analysed De-NOx process
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