16,366 research outputs found

    A General, Sound and Efficient Natural Language Parsing Algorithm based on Syntactic Constraints Propagation

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    This paper presents a new context-free parsing algorithm based on a bidirectional strictly horizontal strategy which incorporates strong top–down predictions (deriva- tions and adjacencies). From a functional point of view, the parser is able to propagate syntactic constraints reducing parsing ambiguity. From a computational perspective, the algorithm includes different techniques aimed at the improvement of the manipu- lation and representation of the structures used

    Nonlinear Reynolds equations for non-Newtonian thin-film fluid flows over a rough boundary

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    We consider a non-Newtonian fluid flow in a thin domain with thickness ηε and an oscillating top boundary of period ε. The flow is described by the 3D incompressible Navier-Stokes system with a nonlinear viscosity, being a power of the shear rate (power law) of flow index p, with 9/5 < p < +∞. We consider the limit when the thickness tends to zero and we prove that the three characteristic regimes for Newtonian fluids are still valid for non-Newtonian fluids, i.e. Stokes roughness (ηε ≈ ε), Reynolds roughness (ηε > ε) regime. Moreover, we obtain different nonlinear Reynolds-type equations in each case.Junta de AndalucíaMinisterio de Economía y Competitivida

    Faraday effect in rippled graphene: Magneto-optics and random gauge fields

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    A beam of linearly polarized light transmitted through magnetically biased graphene can have its axis of polarization rotated by several degrees after passing the graphene sheet. This large Faraday effect is due to the action of the magnetic field on graphene's charge carriers. As deformations of the graphene membrane result in pseudomagnetic fields acting on the charge carriers, the effect of random mesoscopic corrugations (ripples) can be described as the exposure of graphene to a random pseudomagnetic field. We aim to clarify the interplay of these typically sample inherent fields with the external magnetic bias field and the resulting effect on the Faraday rotation. In principle, random gauge disorder can be identified from a combination of Faraday angle and optical spectroscopy measurements.Comment: 7 pages, 4 figure

    Newtonian fluid flow in a thin porous medium with non-homogeneous slip boundary conditions

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    We consider the Stokes system in a thin porous medium Ωε of thickness ε which is perforated by periodically distributed solid cylinders of size ε. On the boundary of the cylinders we prescribe non-homogeneous slip boundary conditions depending on a parameter γ. The aim is to give the asymptotic behavior of the velocity and the pressure of the fluid as ε goes to zero. Using an adaptation of the unfolding method, we give, following the values of γ, different limit systems.Junta de AndalucíaMinisterio de Economía y Competitividad (MINECO). Españ

    Galois Connections between Semimodules and Applications in Data Mining

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    In [1] a generalisation of Formal Concept Analysis was introduced with data mining applications in mind, K-Formal Concept Analysis, where incidences take values in certain kinds of semirings, instead of the standard Boolean carrier set. A fundamental result was missing there, namely the second half of the equivalent of the main theorem of Formal Concept Analysis. In this continuation we introduce the structural lattice of such generalised contexts, providing a limited equivalent to the main theorem of K-Formal Concept Analysis which allows to interpret the standard version as a privileged case in yet another direction. We motivate our results by providing instances of their use to analyse the confusion matrices of multiple-input multiple-output classifiers

    On the Modular Specification of NFPs: A Case Study

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    The modular specification of non-functional properties of systems is a current challenge of Software Engineering, for which no clear solution exists. However, in the case of Domain-Specific Languages some successful proposals are starting to emerge, combining model-driven techniques with aspect-weaving mechanisms. In this paper we show one of these approaches in practice, and present the implementation we have developed to fully support it. We apply our approach for the specification and monitoring of non-functional properties using observers to a case study, illustrating how generic observers defining non-functional properties can be defined in an independent manner. Then, correspondences between these observers and the domain-specific model of the system can be established, and then weaved into a unified system specification using ATL model transformation. Such a unified specification can also be analyzed in a natural way to obtain the required non-functional properties of the system.This work is partially funded by Research Projects TIN2011-23795 and TIN2011-15497-E

    SPANISH COMPANY FOREIGN MARKET ENTRY

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    The aim of this paper is to analyse the determinants of diversification mode (acquisition versus greenfield) through foreign direct investment considering various theories, such as those of mergers and acquisitions, transaction costs, the learning organisation, the institutional context of the company and the cultural environment of the host country, and to analyse the determinants of entry mode combining diversification mode with ownership structure decision (greenfield wholly-owned subsidiaries, greenfield joint ventures, full acquisition and partial acquisition) and proposing various research hypotheses. The methodology used estimates various binomial and multinomial logit models, over a sample of 141 Spanish manufacturing companies between 1998 and 2000, finding that entry mode into a foreign country through direct investment is mainly explained by related diversification, international and local experience, advertising intensity, cultural distance, company size and ownership structure. El propósito de este trabajo consiste en analizar, por un lado, los determinantesdel modo de diversificación (adquisición versus desarrollo interno) de la inversióndirecta en el exterior considerando diversas aproximaciones teóricas, como las defusiones y adquisiciones, costes de transacción, del aprendizaje organizativo, así comodel contexto institucional de la empresa y del entorno cultural del país receptor. Por otrolado, se examinan los determinantes de la inversión directa exterior combinando elmodo de diversificación con la estructura de la propiedad empresarial (adquisición total,adquisición parcial, filial de plena propiedad y filial de propiedad compartida)proponiendo diversas hipótesis de investigación. La metodología aplicada estimadiversos modelos logit, binomial y multinomial, sobre 141 empresas españolasmanufactureras entre 1998 y 2000, detectando que el modo de entrada medianteinversión directa exterior viene explicada por la diversificación relacionada, laexperiencia internacional y local de la empresa, la intensidad publicitaria, la distanciacultural, así como por el tamaño y estructura de la propiedad de la empresa.marketing internacional, modo de entrada, inversión directa en el exterior, joint-venture, adquisición. international marketing, entry mode, foreign direct investment, jointventure, acquisition

    Peanut Shell for Energy: Properties and Its Potential to Respect the Environment

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    The peanut (Arachys hypogaea) is a plant of the Fabaceae family (legumes), as are chickpeas, lentils, beans, and peas. It is originally from South America and is used mainly for culinary purposes, in confectionery products, or as a nut as well as for the production of biscuits, breads, sweets, cereals, and salads. Also, due to its high percentage of fat, peanuts are used for industrialized products such as oils, flours, inks, creams, lipsticks, etc. According to the Food and Agriculture Organization (FAO) statistical yearbook in 2016, the production of peanuts was 43,982,066 t, produced in 27,660,802 hectares. Peanuts are grown mainly in Asia, with a global production rate of 65.3%, followed by Africa with 26.2%, the Americas with 8.4%, and Oceania with 0.1%. The peanut industry is one of the main generators of agroindustrial waste (shells). This residual biomass (25–30% of the total weight) has a high energy content that is worth exploring. The main objectives of this study are, firstly, to evaluate the energy parameters of peanut shells as a possible solid biofuel applied as an energy source in residential and industrial heating installations. Secondly, different models are analysed to estimate the higher heating value (HHV) for biomass proposed by different scientists and to determine which most accurately fits the determination of this value for peanut shells. Thirdly, we evaluate the reduction in global CO2 emissions that would result from the use of peanut shells as biofuel. The obtained HHV of peanut shells (18.547 MJ/kg) is higher than other biomass sources evaluated, such as olive stones (17.884 MJ/kg) or almond shells (18.200 MJ/kg), and similar to other sources of biomass used at present for home and industrial heating applications. Different prediction models of the HHV value proposed by scientists for different types of biomass have been analysed and the one that best fits the calculation for the peanut shell has been determined. The CO2 reduction that would result from the use of peanut shells as an energy source has been evaluated in all production countries, obtaining values above 0.5 ‰ of their total emissions
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