Distribution of statistics D , K and S for human pulse waveforms. The histogram shows the distribution of statistic estimates (D, K and S) for 500 ATS time series generated from each of the four time series depicted in figure 4. The taller vertical line on each plot is the comparable value for the shorter vertical lines are for the (limited) subsequent data recorded from each patient. In each case only two or three subsequent contiguous but non-overlapping time series were available. The figures are: (a) correlation dimension (D), (b) entropy (K), and (c) noise (S) for the normal rhythm; (d) D, (e) K, and (f) S for the quasi-stable rhythm; (g) D, (h) K, and (i) S for the unstable rhythm; and (j) D, (k) K, and (l) S for the post-operative stable rhythm.