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Results

In Figures 1a-c the results for the baker map (4) are presented: The LE as the analytic function (7) of the parameter tex2html_wrap_inline477 (Fig. 1a), the GPER estimated from time series plotted against tex2html_wrap_inline477 (Fig. 1b), and the GPER plotted against the LE (Fig. 1c). The latter plot demonstrates that in the case of the chaotic baker map (4) the LE/KSE and the GPER are related by a nonlinear one-to-one function. Considering precision of the GPER estimates, the same conclusion can be drawn for the Lorenz system (6) for the parameter r varying from 34 to 65 (Figs. 1d-f).

The situation is different in the case of the logistic map (5) (Fig. 2): the basic trends in the dependences of the LE and the GPER on the parameter a (Figs. 2a, 2b, respectively) agree, however, there are clear discrepancies larger than the estimation errors and the functional relation between the GPER and the LE/KSE is lost (Fig. 2c).

Comparing the plots in Fig. 1 and Fig. 2, one can see that in Fig. 1 the LE (KSE) varies smoothly with variations of a system parameter, i.e., the systems change only quantitatively remaining in the chaotic regime, while in the case of the logistic map in Fig. 2 bifurcations into periodic states interrupt the regime of chaotic states. Similarly, the Lorenz system (6) with r> 65 enters the bifurcation region (Figs. 3a,b and 3d,e) and deviations from the bijective functional dependence between the KSE/LE and the GPER occur in the LE values related to the bifurcation region (Fig. 3c and 3f).

When a system parameter exactly fits a periodic-state value, the periodic state with zero KSE and negative LE occurs, which is indicated also by a very low (but positive) GPER valuegif (cf. plot a with plot b, or plot d with plot e in Fig. 2 and Fig. 3). The functional relation between the KSE/LE and the GPER, however, is broken not only in periodic states, but apparently also at any point near a bifurcation. Only two bifurcations appeared in Fig. 2a, when the plot was obtained by increasing the parameter a from 3.857 to 4 by step tex2html_wrap_inline587 . Using smaller step ( tex2html_wrap_inline589 ), seven periodic states were ``hit'' (Fig. 2d). In fact, it is impossible to find any ``bifurcation free'' sub-interval of chaotic states of the logistic map. Note, that there are no bifurcations in the case of the baker map studied in Fig. 1a-c. In the case of the Lorenz system, both situations were observed: A chaotic region with smooth (``bifurcation free'') dependence of the KSE/LE on the parameter r for tex2html_wrap_inline593 in which a one-to-one relation between the KSE/LE and the GPER exists (Fig. 1); and for r>65 a regime of chaotic states suddenly interrupted by bifurcations into periodic states, where digressions from the one-to-one functional dependence of the GPER on the KSE/LE occur (Fig. 3).


next up previous
Next: Transients and critical behaviour Up: On entropy rates of Previous: Numerical study

Milan Palus
Mon Dec 16 09:47:50 EST 1996