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arXiv 1301.4867math-phmath.MPmath.STphysics.data-anstat.TH
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分数阶微积分在随机变量概率特征化中的应用

On the use of fractional calculus for the probabilistic characterization of random variables

Giulio Cottone, Mario Di Paola

摘要:

在本文中,一个随机变量的概率特征的经典问题重新审查。随机变量通常由概率密度函数(PDF)或其傅里叶变换(即特征函数(CF))描述。CF可以进一步由涉及随机变量的矩的泰勒级数表示。然而,在某些情况下,矩不存在,CF的泰勒展开是无用的。例如,在$α$ --稳定随机变量的情况下,就会发生这种情况。在这里,表示的CF或随机变量(r.vs)的PDF的问题是通过引入分数阶微积分检查。得到了两个非常显著的结果。首先,证明了CF在零点处的分数阶导数与分数阶矩一致。这在CF不能在零中导出的情况下也是正确的(如$α$的CF-稳定的相对论)。此外,它表明,CF可以表示为一个广义泰勒展开涉及分数阶矩。提出的广义泰勒级数也能够表示PDF在一个完美的对偶表示的CF。分数阶矩的PDF表示在尾部特别精确,这在工程问题中非常重要,如估计结构安全性。

英文摘要:

In this paper, the classical problem of the probabilistic characterization of a random variable is re-examined. A random variable is usually described by the probability density function (PDF) or by its Fourier transform, namely the characteristic function (CF). The CF can be further expressed by a Taylor series involving the moments of the random variable. However, in some circumstances, the moments do not exist and the Taylor expansion of the CF is useless. This happens for example in the case of $α$--stable random variables. Here, the problem of representing the CF or the PDF of random variables (r.vs) is examined by introducing fractional calculus. Two very remarkable results are obtained. Firstly, it is shown that the fractional derivatives of the CF in zero coincide with fractional moments. This is true also in case of CF not derivable in zero (like the CF of $α$--stable r.vs). Moreover, it is shown that the CF may be represented by a generalized Taylor expansion involving fractional moments. The generalized Taylor series proposed is also able to represent the PDF in a perfect dual representation to that in terms of CF. The PDF representation in terms of fractional moments is especially accurate in the tails and this is very important in engineering problems, like estimating structural safety.

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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