Figure 6.

Multifractal analysis of the IBI time series. The left columns (a, c, and e) represent data for pattern A, and the right columns (b, d, and f) display data for pattern B. (a and b) Partition functions, Z_q(s), of integrated IBI time series. Z_q(s) for several values of q are represented as functions of wavelet scales in logarithmic plots. Vertical crosses, tilted crosses, asterisks, open squares, solid squares, open circles, solid circles, open upward triangles, solid upward triangles, open downward triangles, and solid downward triangles represent the partition functions for q = −5, −4, −3, −2, −1, 0, 1, 2, 3, 4, and 5, respectively. Thin solid lines are the least-squares fits to the data in the range [10^2.5, 10⁴]. (c and d) The spectrum of the scaling exponent, τ(q), for the original IBI time series. (e and f) The spectrum of the local Hölder exponents, D(h), for the original IBI time series.