In this work, the pneumocardiogram signals of nine rats were analysed by scale index, Boltzmann Gibbs entropy and maximum Lyapunov exponents. The scale index method, based on wavelet transform, was proposed for determining the degree of aperiodicity and chaos. It means that the scale index parameter is close to zero when the signal is periodic and has a value between zero and one when the signal is aperiodic. A new entropy calculation method by normalized inner scalogram was suggested very recently. In this work, we also used this method for the first time in an empirical data. We compared the both methods with maximum Lyapunov exponents and observed that using together the scale index and the entropy calculation method by normalized inner scalogram increases the reliability of the pneumocardiogram signal analysis. Thus, the analysis of the pneumocardiogram signals by those methods enables to compare periodical and/or nonlinear aspects for further understanding of dynamics of cardiorespiratory system.

中文翻译：

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非线性方法在心电图信号中的应用

本研究通过标度指数、玻尔兹曼吉布斯熵和最大李雅普诺夫指数对9只大鼠的心肺信号进行了分析。提出了基于小波变换的尺度指数法来确定非周期性和混沌程度。这意味着当信号是周期性的时，尺度指数参数接近于零，而当信号是非周期性的时，它的值在零和一之间。最近提出了一种新的基于归一化内标度图的熵计算方法。在这项工作中，我们也首次在一个经验数据中使用了这种方法。我们将这两种方法与最大 Lyapunov 指数进行了比较，并观察到将标度指数和熵计算方法结合使用归一化内标度图增加了心电图信号分析的可靠性。因此，