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arXiv 1004.3726stat.MEstat.AP
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利用先验知识构造Copula函数

Using a priori knowledge to construct copulas

Dominique Drouet Mari, Valerie Monbet

摘要:

我们的目的是建立两个随机变量之间的依赖关系模型,同时考虑到这些变量的先验知识。例如,在许多应用中(海洋学、金融.),这两个变量之间存在一个顺序关系,当一个取高值时,另一个不能取低值,反之也是可能的。因此,这两个变量的高值的相关性是不对称的。然而,也存在最小的依赖性:一个变量的低值与另一个变量的低值相关联。对于两个变量的最大值或最小值,依赖性也可以是极端的。本文利用混合变量逐步构造了具有渐近最小相关性的非对称copula函数,以及具有或不具有渐近最大相关性的非对称copula函数,首先得到非对称相关性,然后得到最小相关性.我们将这些模型拟合到一个真实的海况数据集上,当它们嵌套时使用似然比检验,否则使用BIC准则(贝叶斯信息准则)进行比较。

英文摘要:

Our purpose is to model the dependence between two random variables, taking into account a priori knowledge on these variables. For example, in many applications (oceanography, finance...), there exists an order relation between the two variables; when one takes high values, the other cannot take low values, but the contrary is possible. The dependence for the high values of the two variables is, therefore, not symmetric. However a minimal dependence also exists: low values of one variable are associated with low values of the other variable. The dependence can also be extreme for the maxima or the minima of the two variables. In this paper, we construct step by step asymmetric copulas with asymptotic minimal dependence, and with or without asymptotic maximal dependence, using mixture variables to get at first asymmetric dependence and then minimal dependence. We fit these models to a real dataset of sea states and compare them using Likelihood Ratio Tests when they are nested, and BIC- criterion (Bayesian Information criterion) otherwise.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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