Before revision:  However, it still suffers from issues such as inconsistency over short-length signals and its tolerance parameter r, susceptibility to signal amplitude changes and insensitivity to self-similarity of time series. We propose modifications to the ApEn and SampEn measures which are defined for 0<r<1, are more robust to signal amplitude changes and sensitive to self-similarity property of time series. We modified ApEn and SampEn by redefining the distance function used originally in their definitions.
After revision:  However, it still suffers from issues such as inconsistency over short-length signals and its tolerance parameter r, susceptibility to signal amplitude changes . A common practice for addressing this issue is to correct their input signal amplitude by its standard deviation. In this study, we first show using simulations that ApEn and SampEn by redefining the distance function used originally in their definitions.