 The quantification for the aleatoric uncertainties can be relatively straightforward to perform, depending on the application.Techniques such as the Monte Carlo method are frequently used.A probability distribution can be represented by its moments (in the Gaussian case, the mean and covariance suffice, although, in general, even knowledge of all moments to arbitrarily high order still does not specify the distribution function uniquely), or more recently, by techniques such as Karhunen–Loève and polynomial chaos expansions.