5,514 research outputs found

    Herramienta autor Indesahc para la creación de cursos hipermedia adaptativos

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    Un elemento fundamental dentro de una plataforma de gestión del aprendizaje (Learning Management Systems, LMS) es la herramienta autor para la producción del material didáctico. En este artículo presentamos un sistema de desarrollo integrado para la creación y evaluación de cursos hipermedia adaptativos accesibles, basados en páginas Web. INDESAHC (Integrated Development System for Adaptive Hypermedia Courses), facilita la introducción del mapa de contenidos del curso, según un modelo del dominio basado en temas, lecciones, conceptos y escenarios tipos, en los cuales se realiza la integración de los archivos de media mediante un entorno visual intuitivo basado en plantillas. Una vez definidas las relaciones entre los temas y los niveles de dificultad de cada lección, se genera el curso hipermedia adaptativo, cuyo diseño final puede ser evaluado a través de una herramienta accesorio llamada EPRules (Educational Prediction Rules). Esta herramienta utiliza algoritmos de minería de datos, para el descubrimiento de información útil para facilitar un proceso de retroalimentación. Se describe además, el modelo didáctico en que se basa INDESAHC y se presenta una metodología eficaz, para evitar los problemas de desorientación y sobrecarga de contenidos en la navegación.In this paper we present an integrated development system for Web Based Adaptive Hypermedia Courses. We have developed an authoring tool called INDESAHC (Integrated Development System for Adaptive Hypermedia Courses) for this purpose. This tool facilitates to the course designer introducing the conceptual map, according to a domain model based on topics, lessons, concepts and learning components. Furthermore, the program allows the integration of media files in the course by means of an intuitive visual environment based on templates. Once defined the relationship among the topics and the difficulty level of each lesson, the user can generate the hypermedia adaptive course. The final design could be evaluated with an accessory tool called EPRules (Educational Prediction Rules). This tool is based on data mining algorithms in order to discover useful information for feedback. We also discuss on how our methodology can avoid the problems of disorientation and cognitive overload

    Glacis calcisolico y suelos con horizon cálcico en el NE de la provincia de Granada

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    [Resumen] La importancia del estudio de las zonas semiáridas parece incuestionable ya que constituyen uno de los ecosistemas más extensos del mundo. España en concreto es el país de Europa que tiene las zonas más extensas y además coinciden con los ambientes socialmente más deprimidos, cuyas características derivan de la aridez ambiental. En el sector nororiental de la provincia de Granada se localiza la Depresión de Baza, definida por un altiplano con una altitud media de 950 metros. La geomorfología queda dibujada por dos conjuntos: alineaciones montañosas y altiplanicie, dando ésta última un paisaje singular que por su extrema sequedad constituye uno de los paisajes más característicos de las zonas esteparias peninsulares. La desigual evolución de los suelos nos permite detallar en el presente trabajo la unidad edafogeomorfológica del glacis calcisólico, desarrollada por denudación de la superficie del glacis lúvico antiguo y la materialización de suelos con horizonte cálcico, originado antiguamente por precipitación del carbonato cálcico ante la desecación del suelo en la estación seca, o petrocálcico 9riginado tras repetidas redisoluciones y reprecipitaciones de la caliza, con fuerte cementación final.[Abstract] Semiarid zones are the vastest ecosystems in the world, therefore their study is very important. Spain is the european country supporting mostly european semiarid zones, moreover these areas are underdeveloped because of their arid environment. The Baza Depresion is located at the north-east of Granada province and is a high plateau with 950m altitude average. Geomorphology is composed for two formations: a mountainous area and a high plateau; this offers a singular landscape making up one of the most characteristics Spanish sttepe. In this study, the calcisolic glacis edaphogeomorphological unit is detailed. This unit is developed by denudation of the old luvic glacis and soils with calcic horizon; this horizon was originated by calcium carbonate precipitation during the dry season, or in the case of petrocalcic horizon, originated by repeated redisolutions and reprecipitations of the calcium carbonate

    Algoritmos Evolutivos para Descubrimiento de Reglas de Predicción en la Mejora de Sistemas Educativos Adaptativos basados en Web

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    Este artículo muestra la utilización de los algoritmos evolutivos para el descubrimiento de reglas de predicción que se utilizarán en la mejora de Cursos Hipermedia Adaptativos basados en Web. Se ha desarrollado una herramienta de minería de datos específica para descubrir relaciones entre los datos de utilización recogidos durante las ejecuciones de los distintos alumnos. Esta información puede ser de gran utilidad para el profesor o autor del curso, para la toma de decisiones sobre qué modificaciones son las más adecuadas para mejorar el aprendizaje de los alumnos. Para la realización de la búsqueda de reglas de predicción se ha utilizado programación genética basada en gramáticas multi-objetivo y se han comparado con algoritmos clásicos de descubrimiento de reglas.In this paper we show the use of evolutionary algorithms for discovering prediction rules to improve web-based adaptive hypermedia courses. We have developed a specific data mining tool to discover relationship between the usage data pickup during the execution of different students. This information can be very useful to the courseware author in order to make decisions about what are the most appropriated modifications to improve the learning of the students. In order to do prediction rule discovering we have used multi-objective grammar-based genetic programming and we have compared it with other classic algorithm for rule discovering

    Experimental study about the effects of granular skeleton distribution on the mechanical properties of self-compacting concrete (SCC)

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    In recent years, the use of self-compacting concrete (SCC) has been increasing. Although methods for designing the mixture proportions usually derive from experience with conventional concretes, some specific procedures still are not universally accepted. The design and characterization of SCC influences not only the mix components (paste volume and nature, binder amount and type, granular skeleton, etc.) but also the testing methods used to validate the self-compactability (usually in terms of rheology, fluidity, viscosity and resistance to segregation). This paper studies the influence on SCC mechanical properties based on the consideration of two types of granular skeleton, discontinuous and continuous, for different strength levels (35 and 60 MPa). For the both strength levels studied, the mix with continuous granular skeleton exhibited slightly higher segregation resistance and mechanical properties than did mixes with discontinuous granular skeleton. (C) 2015 Elsevier Ltd. All rights reserved.Peer ReviewedPostprint (author’s final draft

    Estudio de digénidos de peces marinos del sur de la Península Ibérica

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    Se han estudiado un total de 492 hospedadores pertenecientes a 72 especies de peces marinos, todos procedentes de la plataforma continental que bordea el sur de la Península Ibérica. Como resultado de este trabajo se han localizado en el aparato digestivo de estos hospedadores 39 especies de Digenea. De ellas, Stephanostomum bicoronatum, (Stossich, 1883) Manter, 1940, Parahemiurus merus, (Linton, 1910) Manter, 1940, Derogenes latus Janiszewska, 1953, Bacciger israelensis Fischtha1, 1980, Promnoprymna ventricosa (Rudolphi, 1819) Poche, 1926, Haploporus benedenii (Stossich, 1887) Looss, 1902, Haplosplanchnus pachysomus (Eysenhardt, 1829) Looss, 1902, Saccocoelium obesum Looss, 1902, y Genolopa ampullacea Linton, 1910 se citan por primera vez en la península Ibérica. Lecithochirium musculus (Looss, 1907) Nasir y Díaz, 1971, Lecithochirium rufoviride (Rudolphi, 1819) Lühe, 1901, Lecithochirium fusiforme Lühe, 1901, Ectenurus lepidus Looss, 1907 y Tergestia laticollis (Rudolphi, 1819) Stossich, 1899, en las costas de Andalucia. Stephanostomum minutum en el Mediterráneo peninsular. Wardulla capitel/ata (Rudolphi, 1819) Poche, 1926 y Deropristis inflata en el Atlántico peninsular. Además, con el presente trabajo se amplía considerablemente el espectro de hospedadores de algunas de las especies parásitas estudiadas. Así Halobatrachus didactylus es nuevo hospedador para Stephanostomum minutum (Looss, 1901) Manter, 1940, Anisocladium fallax (Rudolphi, 1819) Looss, 1902 y Anisocoelium capitellatum (Rudolphi, 1819) Lühe, 1900. Bothus podas para Lecithocladium excisum (Rudolphi, 1819) Lühe, 1901 y Derogenes varicus (Müller, 1784) Looss, 1901. Solea sp. para Lecithochirium musculus (Looss, 1907) Nasir y Díaz, 1971. Trachinotus ovatus para Synaptobothrium caudiporum (Rudolphi, 1819) Looss, 1907. Scorpaena scrofa para Derogenes latus Janiszewska, 1953. Belone belone para Tergestia laticollis (Rudolphi, 1819) Stossich, 1899. Dicentrarchus punctatus para Acanthostomum imbutiforme (Molin, 1859) Gohar, 1934 y Bucephalus baeri Maillard, 1976. y Echiichthys vipera para Anisocladiumfallax (Rudolphi, 1819) Looss, 1902 y Anisocoelium capitellatum (Rudolphi, 1819) Lühe, 1900A total of 492 host of72 diferent species ofmarine fishes were colleted from the Sourth Iberian Peninsula coast and their tract digest were examined. We have identified 39 species ofDigenea. Stephanostomum bicoronatum, (Stossich, 1883) Manter, 1940, Parahemiurus merus, (Linton, 1910) Manter, 1940, Derogenes latus Janiszewska, 1953, Bacciger israelensis Fischthal, 1980, Promnoprymna ventricosa (Rudolphi, 1819) Po che, 1926, Haploporus benedenii (Stossich, 1887) Looss, 1902, Haplosplanchnus pachysomus (Eysenhardt, 1829) Looss, 1902, Saccocoelium obesum Looss, 1902, and Genolopa ampullacea Linton, 1910, have not previously been reported from Iberian Peninsula. Furthermore, Lecithochirium musculus (Looss, 1907) Nasir y Díaz, 1971, Lecithochirium rufoviride (Rudolphi, 1819) Lühe, 1901, Lecithochirium fusiforme Lühe, 1901, Ectenurus lepidus Looss, 1907 and Tergestia laticollis (Rudolphi, 1819) Stossich, 1899, are reported for the first time in Andalucian coast; Stephanostomum minutum in the spanish mediterranean coast and finally, Wardulla capitellata (Rudolphi, 1819) Poche, 1926 and Deropristis inflata in the Atlántic peninsular. In this paper, we have thoroughly widened the host range for sorne of the species here studied. So, Halobatrachus didactylus is a new host for Stephanostomum minutum (Looss, 1901) Manter, 1940, Anisocladiumfallax (Rudolphi, 1819) Looss, 1902 and Anisocoelium capitellatum (Rudolphi, 1819) Lühe, 1900. Bothus podas for Lecithocladium excisum (Rudolphi, 1819) Lühe, 1901 and Derogenes varicus (Müller, 1784) Looss, 1901. Solea sp. for Lecithochirium musculus (Looss, 1907) Nasir y Díaz, 1971. Trachinotus ova tus for Synaptobothrium caudiporum (Rudolphi, 1819) Looss, 1907. Scorpaena scrofa for Derogenes latus Janiszewska, 1953. Belone belone for Tergestia laticollis (Rudolphi, 1819) Stossich, 1899. Dicentrarchus punctatus for Acanthostomum imbutiforme (Molin, 1859) Gohar, 1934 and Bucephalus baeri Maillard, 1976. Echiichthys vipera for Anisocladiumfallax (Rudolphi, 1819) Looss, 1902 andAnisocoelium capitellatum (Rudolphi, 1819) Lühe, 190

    An Automatic Tree Search Algorithm for the Tisserand Graph

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    The Tisserand graph (TG) is a graphical tool commonly employed in the preliminary design of gravity-assisted trajectories. The TG is a two-dimensional map showing essential orbital information regarding the Keplerian orbits resulting from the close passage by one or more massive bodies, given the magnitude of the hyperbolic excess speed (vv_{\infty}) and the minimum allowed pericenter height for each passage. Contours of constant vv_{\infty} populate the TG. Intersections between contours allow to link consecutive flybys and build sequences of encounters en route to a selected destination. When the number of perturbing bodies is large and many vv_{\infty} levels are considered, the identification of all the possible sequences of encounters through the visual inspection of the TG becomes a laborious task. Besides, if the sequences are used as input for a numerical code for trajectory design and optimization, an automated examination of the TG is desirable. This contribution describes an automatic technique to explore the TG and find all the encounter paths. The technique is based on a tree search method, and the intersections between contours are found using the regula-falsi scheme. The method is validated through comparisons with solutions available in the open literature. Examples are given of application to interplanetary mission scenarios, including the coupling with a trajectory optimizer

    Conformal topological Yang-Mills theory and de Sitter holography

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    A new topological conformal field theory in four Euclidean dimensions is constructed from N=4 super Yang-Mills theory by twisting the whole of the conformal group with the whole of the R-symmetry group, resulting in a theory that is conformally invariant and has two conformally invariant BRST operators. A curved space generalisation is found on any Riemannian 4-fold. This formulation has local Weyl invariance and two Weyl-invariant BRST symmetries, with an action and energy-momentum tensor that are BRST-exact. This theory is expected to have a holographic dual in 5-dimensional de Sitter space.Comment: 34 pages, AMSTex, Reference adde

    Searching for New Physics in Leptonic Decays of Bottomonium

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    New Physics can show up in various well-known processes already studied in the Standard Model, in particular by modifying decay rates to some extent. In this work, I examine leptonic decays of Υ\Upsilon vector resonances of bottomonium below BBˉB\bar{B} production, subsequent to a magnetic dipole radiative structural transition of the vector resonance yielding a pseudoscalar continuum state, searching for the existence of a light Higgs-like neutral boson that would imply a slight but experimentally measurable breaking of lepton universality.Comment: LaTeX, 12 pages, 1 EPS figur

    On non-abelian T-dual geometries with Ramond fluxes

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    We show how to implement T-duality along non-abelian isometries in backgrounds with non-vanishing Ramond fields. When the dimension of the isometry group is odd (even) the duality swaps (preserves) the chirality of the theory. In certain cases a non-abelian duality can result in a massive type-IIA background. We provide two examples by dualising SU(2) isometry subgroups in AdS5×S5AdS_5\times S^5 and AdS3×S3×T4AdS_3\times S^3\times T^4. The resultant dual geometries inherit the original AdS factors but have transverse spaces with reduced isometry and preserve only half of the original supersymmetry. The non-abelian dual of AdS5×S5AdS_5\times S^5 has an M-theory lift which is related to the gravity duals of N=2 superconformal theories. We comment on a possible interpretation of this as a high spin limit.Comment: 33 page
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