20 years of ordinal patterns: Perspectives and challenges

Abstract In 2002, in a seminal article, Bandt and Pompe proposed new methodology for the analysis of complex time series, now known as Ordinal Analysis. The ordinal is based on computation symbols (known patters) which are defined terms temporal ordering data points whose probabilities probabilities. With Shannon entropy can be calculated, permutation entropy. Since it was proposed, method has found applications fields diverse biomedicine climatology. However, some properties still not fully understood, how to combine approach feature extraction with machine learning techniques model identification, series classification or forecasting, remains challenge. objective this perspective article present recent advances discuss open problems.