Figure 2

The schematic of the Modified Diffusion Entropy Analysis (MDEA). Panel (a): The blue curve is L = 10 s (\(10\times 512\) samples) of the heart rate signal (as an example time series) which was first projected to the interval [0,1] and then divided into ten stripes of size of 0.1. The horizontal lines in panel (a) define the stripes. The top panel on the right is a zoomed in section of the panel (a) where the red circles represent the events as the times when the signal (blue curve) passes from one stripe to another. Panel (b): The extracted events in panel (a) assigned the value 1 to create a binarized time series. Panel (c): The diffusion trajectory made by cumulative summation of the events of panel (b). Panel (d): Slices (of length \(w =100\) samples; 100/512 samples/s = 0.195 s and starting from an event) from the diffusion trajectory which are shifted to start from the origin. Panel (e): The histogram of the position of the trajectories of panel (d) at the end of the window (\(w=100\) samples). To create the histogram of panel (e) we used L = 60 s (\(60\times 512\) samples) of data and stripe size of 0.01, which are the MDEA parameters used in this work.) Note that for purposes of illustration the above figures (panels (a)–(d)) are only L = 10 s (10\(\times\)512 samples) of data and we chose stripe size of 0.1 to enable visualization of individual heart beats.