31 research outputs found

    Sociologia moral das dependências motivadas: o caso da dependência amorosa

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    Este artigo propõe um panorama do procedimento e dos métodos da sociologia moral, que se baseiam em uma etnofilosofia da existência social comum e em uma antropologia natural. A primeira parte do texto situa a sociologia moral em relação ao desenvolvimento contemporâneo das pesquisas empíricas sobre a ética, sobretudo no âmbito da psicologia experimental e evolucionista. A segunda parte apresenta alguns elementos de uma teoria das dependências motivadas aos prazeres e às recompensas, desenvolvida a partir do aporte das neurociências da adição e de pesquisas de campo sobre as condutas aditivas e as tentativas de restabelecimento. A terceira parte propõe uma ilustração do método a partir de uma pesquisa recente sobre a dependência amorosa, feita principalmente a partir de um corpus literário e cinematográfico

    A general framework for coupled hydro-mechanical modelling of rainfall-induced instability in unsaturated slopes with multivariate random fields

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    An accurate estimation of rainfall-induced instability of slopes for extremely nonhomogeneous materials such as lignite mine spoils is a major challenge. This paper investigates the stability of nonhomogeneous soil slopes with respect to slip surface development, size of sliding volume, and determination of safety factor. Specified dependent random variables are cross-correlated using a multivariate Gaussian copula, the use of which provides a faster and more accurate representation of the inter-dependent properties of randomly-distributed soil. A Monte-Carlo simulation is used to generate a series of multivariate random fields for slopes. These are then implemented in Abaqus and analysed under constant rainfall conditions using a fully coupled hydro-elasto-plastic model. The resulting stress, strain, pore pressure, and displacement data are further processed in MATLAB to evaluate critical slip surfaces and safety factors. Results indicate that the factor of safety in a homogenous case is overestimated compared to the nonhomogeneous condition, while the sliding volume is underestimated. Moreover, the factor of safety decreases as the rainfall simulation continues and the probability of failure increases to nearly 100% after 10 days of rainfall. The framework developed in this paper can provide guidance for conducting relatively inexpensive probabilistic analyses

    Sampling from Archimedean copulas

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    We develop sampling algorithms for multivariate Archimedean copulas. For exchangeable copulas, where there is only one generating function, we first analyse the distribution of the copula itself, deriving a number of integral representations and a generating function representation. One of the integral representations is related, by a form of convolution, to the distribution whose Laplace transform yields the copula generating function. In the infinite-dimensional limit there is a direct connection between the distribution of the copula value and the inverse Laplace transform. Armed with these results, we present three sampling algorithms, all of which entail drawing from a one-dimensional distribution and then scaling the result to create random deviates distributed according to the copula. We implement and compare the various methods. For more general cases, in which an N-dimensional Archimedean copula is given by N-1 nested generating functions, we present algorithms in which each new variate is drawn conditional only on the value of the copula of the previously drawn variates. We also discuss the use of composite nested and exchangeable copulas for modelling random variates with a natural hierarchical structure, such as ratings and sectors for obligors in credit baskets.
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