“…The popular parameters in this category are computed using the fractal dimension or the correlation dimension [28], [45], [51]- [53]. The complex measures investigated in several studies consist of the following: the largest Lyapunov exponent, the recurrence period density entropy, Hurst exponent, detrended fluctuation analysis, approximate entropy, sample entropy, modified sample entropy, Gaussian kernel sample entropy, fuzzy entropy, hidden Markov model (HMM) entropy and Shannon HMM entropy [38], [39], [54], [55]. These features capture the dynamic variants/invariants, long-range correlations, regularity or predictability information present in the signal.…”