2,473 research outputs found

    Automatic exploitation of non-determinate independent and-parallelism in the basic andorra model

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    Andorra-I is the first implementation of a language based on the Andorra Principie, which states that determinate goals can (and shonld) be run before other goals, and even in a parallel fashion. This principie has materialized in a framework called the Basic Andorra model, which allows or-parallelism as well as (dependent) and-parallelism for determinate goals. In this report we show that it is possible to further extend this model in order to allow general independent and-parallelism for nondeterminate goals, withont greatly modifying the underlying implementation machinery. A simple an easy way to realize such an extensión is to make each (nondeterminate) independent goal determinate, by using a special "bagof" constract. We also show that this can be achieved antomatically by compile-time translation from original Prolog programs. A transformation that fulfüls this objective and which can be easily antomated is presented in this report

    EFFECTS OF LOUVERS SHADING DEVICES ON VISUAL COMFORT AND ENERGY DEMAND OF AN OFFICE BUILDING. A CASE OF STUDY

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    This paper evaluates the building energy demand and visual comfort of a real case with a glazed façade office building placed in Málaga (Mediterranean city in the south of Spain). South oriented facades receive such a high solar gain that cooling demand cannot be handled by the current HVAC system. As an environmental friendly solution, a shading control strategy based on vertical and horizontal louvers is proposed. The study consists of a comparison between the actual and the refurbished building with shading devices. Daylighting simulation is done with Daysim (Daysim, 2016). A group of offices with south, east and north oriented facades is chosen for the study. Horizontal louvers in the south façade and vertical louvers in the east facade are modelled and simulated. The simulation changes the angle of the louver: 0º (perpendicular to the glazing), -30º, 30º, -60º, 60º. Visual comfort parameters analyzed are: illuminance, daylight autonomy (DA) and useful daylight index (UDI). With respect to the thermal comfort, not only louvers orientation try to provide solar protection for glazed areas in cooling period but also maximize solar gains in heating period. However, an excessive daylight could affect discomfort glare. Shading control strategy must provide the equilibrium between both aspects. Thermal demand is calculated with Trnsys (TRNSYS, 2016).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Procedure to Prepare and Model Speed Data Considering the Traffic Infrastructure, as Part of a Cyber-Physical System

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    This chapter investigates the relationship between traffic control infrastructure (traffic lights and speed bumps) and the vehicles’ travel speeds, for certain hours and days of the week. The authors propose the following procedures: (1) street segmentation, (2) clustering and categorization of speed data, (3) histograms’ comparison analysis, (4) outlier detection, (5) modeling, and (6) delivering info to the users. Comparing speed histograms, segments with matching infrastructure presented similarities, regardless of the day of the week. Two techniques to model data were employed: polynomial regression and multinomial logistic regression. The algorithms to predict the travel speed category were also developed. The first technique yields on average 91.3% of data categorized correctly, and the second gets 90.09%. The traffic lights and speed bumps, located on the street segments under consideration, were identified as variables causing different travel speeds. The procedure allows to incorporate more traffic elements and can also be applied to other geographical locations

    Análisis de secuencias de aprendizaje matemático desde la perspectiva de la gestión de la participación

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    El aula de matemáticas puede ser objeto de análisis desde muy diversas perspectivas. En este artículo se estudia la gestión de la participación de los alumnos en los procesos de aprendizaje relacionados con el contenido matemático. Para ello desarrollamos un instrumento de análisis y mostramos su utilidad aplicándolo a una sesión sobre polígonos. Nos centramos en cómo la maestra promueve procesos de responsabilización, comunicación y validación.The mathematics classroom can be analysed from many perspectives. In this paper the focus is on the pupils' participation management in the mathematics learning processes. For this we developed an analytical tool and showed its application on a lesson on polygons. We looked at the way the teacher promotes processes of responsibilisation, communication and validation

    Complex interactions in microbial food webs : stoichiometric and functional approaches

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    The food web structure in some high mountain lakes deviates from the established tendency of high heterotrophic bacteria: phytoplankton biomass ratios in oligotrophic ecosystems. Thus, the microbial food web in La Caldera Lake is weakly developed, and bacteria constitute a minor component of the plankton community in terms of abundance, biomass and production. Autotrophic picoplankton is absent, and heterotrophic microbial food web is weakly developed compared to a grazing chain dominated by calanoid copepods and a phytoplankton community mainly composed of mixotrophic flagellates. In order to explain the singular food web structure of this lake, functional, stoichiometric and taxonomical approaches are followed to assess, on various temporal and spatial scales, the relevance of stressful abiotic factors (ultraviolet solar radiation and P-limitation) on the structure and functioning of this ecosystem. P-availability was the main factor controlling the algal biomass whereas bacterial P- limitation was a transient phenomenon. The algae-bacteria relationship was predominately commensalistic. In contrast to algae, full-sunlight radiation had no negative effect on bacterial growth but rather enhanced bacterial dependence on the carbon released by algae. The prevalence of the commensalistic-mutualistic relationship and the development of a more complex microbial food web were related to the stoichiometry of algae and bacteria (N:P ratios). The microbial food web only developed at balanced algal and bacterial N:P ratios, with the appearance of ciliates after a nutrient pulse. However, mixotrophic algae dominated the planktonic community under P-deficit conditions, and they were the main factor controlling bacterioplankton. Their regulatory effect has a dual nature: (i) a resource-based control, where bacteria depend on the photosynthetic carbon released by algae, i.e., a commensalistic interaction ("without you I cannot live"); and (ii) a predatory control, where bacteria is a prey for mixotrophs ("with you I die"). Hence, the niche of microheterotrophs (nanoflagellates and ciliates) is occupied by mixotrophs, and there is a resulting simplification of the planktonic structure. With respect to the carbon cycle, mixotrophic bacterivory constitutes a "by-pass" for the flux of C towards the grazing chain, precluding the development of a complex heterotrophic microbial food web. Mixotrophs thereby improve the energetic transfer efficiency in high mountain lakes through a reduction in the number of trophic levels. Antagonistic effects of UVR x P interactions on the algae-bacteria relationship were caused by an enhancement of dual (resource and predation) control. Based on these results, an alternative model for the flux of C in autotrophic high mountain lakes has been proposed.La estructura de la red trófica en algunos lagos de alta montaña, se aleja de los patrones establecidos para ecosistemas oligotróficos que proponen el predominio de la red trófica microbiana sobre la cadena de pastoreo. Así, en la laguna de La Caldera las bacterias son el componente minoritario de la comunidad planctónica en términos de abundancia, biomasa y producción. El picoplancton autótrofo está ausente y la red microbiana heterotrófica se encuentra escasamente desarrollada frente a una cadena de pastoreo dominada por copépodos calanoides y algas mixotróficas. Para comprender los mecanismos que determinan esta estructura trófica hemos seguido diferentes aproximaciones de análisis: funcional, estequiométrica y taxonómica sobre distintas escalas espaciales y temporales, en relación con los principales factores de estrés abiótico (radiación ultravioleta y limitación por fósforo) que controlan el funcionamiento de los ecosistemas de alta montaña. Nuestros resultados indican que la disponibilidad de fósforo, de forma generalizada, controla la biomasa algal y de manera transitoria la bacteriana, estableciéndose entre ambas comunidades una relación comensalista. La radiación solar completa no afecta negativamente el desarrollo de las bacterias y si el de las algas y potencia la relación de dependencia por el carbono orgánico (comensalismo) entre algas y bacterias. El predominio de la relación comensalista-mutualista y el desarrollo del bucle microbiano esta relacionado con la estequiometría (razón N:P) de algas y bacterias. Así, sólo cuando la razón N:P de algas y bacterias es equilibrada para crecer, un pulso de nutrientes permite el desarrollo del bucle microbiano. En condiciones naturales de déficit de P, sin embargo, existe un predominio de "algas" con metabolismo mixotrófico. Las algas mixotróficas ejercen un efecto regulador dual sobre las bacterias que denominamos Ni contigo ni sin ti, (i) control por depredación, donde las bacterias son consumidas por algas mixotróficas ("contigo me muero"), (ii) control basado en los recursos estableciéndose una relación de dependencia de las bacterias sobre del carbono liberado por las algas ("sin ti no puedo vivir"). La mixotrofia supone un simplificación en la cadena trófica microbiana, donde los mixótrofos ocupan el nicho potencial de nanoflagelados y ciliados. Desde un punto de vista energético implica un cortocircuito en el flujo de energía y un incremento en la eficiencia de transferencia energética en ecosistemas ultraoligotróficos y con alta dosis de radiación ultravioleta (RUV). Los efectos de la interacción entre RUV y pulsos de P tienen un efecto antagónico sobre la interacción alga-bacteria, intensificando la interacción comensal-depredadora. A partir de los resultados obtenidos proponemos un modelo alternativo de flujo de energía para ecosistemas autotróficos de alta montaña

    Desarrollo humano y género en la región noroeste de México: 1995-2005

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    Un análisis longitudinal del desarrollo humano por género en tres quinquenios se presenta para la región Noroeste de México. Varios índices e indicadores se usan para exhibir la incorporación de opciones de desarrollo en general y por género. Dentro de la heterogeneidad de los estados en la región se observa un avance en las condiciones de vida y en la equidad de género, más notables de 1995 a 2000. En educación, la región supera al promedio nacional y existe una razonable equidad entre géneros; el ingreso, a excepción de Sinaloa, es mayor que el nacional, con significativa inequidad desfavorable a las mujeres, pero cerrándose el rezago; en salud, Baja California y Sonora (frontera) abajo de la media nacional y Baja California Sur y Sinaloa por arriba, es el factor crítico de la región, donde la recurrente diferencia en esperanza de vida entre mujeres y hombres se hace mayor. La ventaja comparativa de la región por su vecindad con Estados Unidos se plasma en el ingreso y la educación, mientras que la violencia erosiona el bienestar de la población. El desarrollo humano y la equidad de género han mejorado pero la violencia e inequidad en sus distribuciones ensombrecen los logros
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