Improving probability distribution estimation accuracy using polynomial
approaches with the method of moments
Abstract
Moment-based determination of a probability density function (PDF) is
widely used in chemical and process engineering applications as they
provide an efficient approach to analyze and solve complex systems. In
this study, three different approaches are implemented for estimating
probability distributions from their moments. These procedures are based
on the reconstruction of a distribution knowing only a limited number of
moments using Chebyshev polynomials, Hermite polynomials and Lagrange
polynomials. To show the applicability of these approaches, various test
cases with reduced set of moments are solved with a set of standard
distribution families (Normal, Weibull, Log Normal and Bimodal) and with
complex distributions (Smoluchowski coagulation equation and population
balance equation). The results are compared with their analytical
solutions using both small and big variance distributions. The
Kolmogorov-Smirnov (K-S) matrix and the RMSE values of the interpolation
procedure using Lagrange polynomials predict a better estimation for all
the test cases compared to the other approaches including the standard
monomial approach (with higher number of moments) implemented in this
study. The K-S test values decreased by 19% compared to the standard
monomial procedure and 11% compared to both Chebyshev and Hermite
polynomial approaches. Similarly, the RMSE values improved by 85%
compared to the standard monomial procedure and 62% compared to both
Chebyshev and Hermite polynomial approaches. This indicates that the
procedure using Lagrange polynomials is a more reliable reconstruction
procedure that calculates the approximate distribution using lesser
number of moments N which is desirable.