432 research outputs found

    Planificación de la nutrición para lotes de gallinas ponedoras, usando técnicas de optimización lineal difusa

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    In this work the fuzzy formulation of the diet problem in the planning of the nutrition of the farms of laying hens is done, and then it is solved applying the methods proposed by Lai and Hwang and by Zimmermann.Finally, we solve a nutritional planning problem with twelve products of which 4 are diffuse and with 10 nutritional substances.En éste trabajo se hace la formulación difusa del problema de la dieta en la planificación de la nutrición de las granjas de gallinas ponedoras, luego se resuelve aplicando los métodos propuesto por Lai y Hwang y por Zimmermann. Finalmente, resolvemos un problema de planificación nutricional con doce productos de los cuales 4 son difusos y con 10 sustancias nutricionales

    Otimização multiobjetivo no balanço econômico da biomassa de colheita da cana-de-açúcar

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    The fact that Brazil is the world's largest sugarcane (Saccharum spp.) producer, leads to a great concern about the cropping systems used, since the most common practice involves manual harvesting prior to straw burning. Brazilian authorities approved a law prohibiting the burning practice of crop residues prior to harvest. However mechanized harvest creates the new problem of how to deal with the residues. Many studies have proposed the use of these residues as an energy source. The major difficulty in its use is how to economically transport sugarcane harvested biomass from the farm to a processing center. The aim of this work was to develop a model to optimize plant variety selection, minimize the cost of the residual biomass transfer process, to evaluate the economics of using this material, and to address sucrose production and planting area constraints, considering distances from plot to processing center. For this 0-1 multiple objective linear programming techniques were used. The results show the viability of the model in selecting varieties, which provide increased profit from residual biomass use.O Brasil é o maior produtor de cana-de-açúcar (Saccharum spp.) do mundo. Mas, existe uma grande preocupação com o sistema de colheita utilizado nesta cultura, pois é prática comum a colheita manual com a pré-queima do palhiço. Autoridades brasileiras têm aprovado leis proibindo a queimada nos canaviais. Entretanto, a colheita mecanizada com cana crua cria novos problemas com a permanência do resíduo no solo. Assim, muitos estudos têm sido propostos para o uso deste resíduo para geração de energia. A maior dificuldade para o uso desta biomassa está no custo de coletar e transferir o resíduo do campo para o centro de processamento. Para análise da viabilidade deste sistema há a necessidade de um estudo do balanço econômico do processo. O objetivo deste trabalho é desenvolver um modelo matemático que auxilie na escolha das variedades de cana a serem plantadas, de forma a minimizar o custo do processo de transferência da biomassa residual de colheita e avaliar economicamente o uso deste material, colocando restrições sobre a produção de sacarose e limitações da área para plantio e considerando as distâncias entre os talhões e o centro de processamento. Para isto, técnicas de programação linear multiobjetivo 0-1 foram utilizadas. Os resultados da aplicação mostram a viabilidade do uso deste modelo para auxílio na seleção de variedades, otimizando o lucro do uso da biomassa residual de colheita para geração de energia

    Optimización Difusa Multiobjetiva en la Planificación de un Sistema de Generación de Energía Eólica

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    En este trabajo se formula un modelo de optimización multiobjetiva para la planificación de un centro de generación eólica que maximiza el ingreso y minimiza los desequilibrios de los costos de oferta. La estrategia de la solución que se utiliza está basada en la teoría de optimización difusa, en la que se utiliza la función de pertenencia linea

    MODELOS Y MÉTODOS DE OPTIMIZACIÓN LINEAL CON INCERTIDUMBRE: UNA BREVE REVISIÓN DEL ESTADO DEL ARTE

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    In the modeling of many problems on linear optimization is not possible to consider the classic deterministic model because the set of parameters is not fully known due to the significant variation of the data along time or because there is no uniformity on the values. These kind of problems are known as problems with uncertainty and there are different approaches about modeling and methods of solution to resolve them. In this paper we make a review of such approaches focusing basically in stochastic optimization, fuzzy optimization, intervaling optimization and hybrid optimization. The difference between these approaches is perceived in the nature of the data, notions of feasibility and optimality and computational requirements, among others.En la modelación de muchos problemas de optimización lineal no es posible considerar el modelo clásico determinista, porque el conjunto de los parámetros no son completamente conocidos debido a que los datos varian en forma significativa a lo largo del tiempo o porque no hay homogeneidad en los valores.Estos problemas son conocidos como problemas con incertidumbre, para los cuales existen diversos enfoques en la modelación y en los métodos de solución. En este artículo se revisa tales enfoques, incidiendo fundamentalmente en la optimización estocástica, optimización difusa, optimización intervalar y optimización híbrida. La diferencia entre estos enfoques se perciben en la naturaleza de los datos, nociones de factibilidad y optimalidad, requerimientos computacionales, entre otros

    Modelo básico epidemiológico SIR para el COVID-19: caso las Regiones del Perú

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    In this work, a basic epidemiological model is used to determine the evolution of COVID-19 in each of the regions of Peru. For determining the parameters of the model which characterize a certain epidemic, the reports of infected, deceased and recovered people provided by the Regional Health Management of Peru are used. As a result, we obtained the configuration of the infected, susceptible and removed which are consistent with the existing bibliography, thus we also obtain a time interval in which there is a considerable number of infected, the maximum number of infected and the date on which it occurs.En este trabajo se utiliza un modelo epidemiológico básico para determinar la evolución del COVID-19 en cada una de las regiones del Perú. Para determinar los parámetros del modelo que caracteriza una determinada epidemia, se utiliza los reportes de las personas infectadas, fallecidas y recuperadas proporcionados por las Gerencias Regionales de Salud del Perú. Como resultado, se obtiene la configuración de los infectados, susceptibles y removidos que concuerda con la bibliografía existente, así también se obtiene un intervalo de tiempo en que hay un considerable número de infectados, el máximo de infectados y la fecha en que ocurre

    Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

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    We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

    Long-range angular correlations on the near and away side in p&#8211;Pb collisions at

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    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe
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