Nagarajan Radhakrishnan
University of Arkansas for Medical Sciences, Center on Aging, 629 S. Elm Street, Room 3105, Little Rock, AR 72205, USA.
IEEE Trans Biomed Eng. 2002 Nov;49(11):1371-3. doi: 10.1109/TBME.2002.804582.
The oscillations observed in physiological data can be attributed largely to the presence of either a nonlinear deterministic or a nondeterministic component. The Lempel-Ziv complexity and its variants have been used successfully to quantify the regularity of these oscillations. The decrease in the complexity can be observed in the case of nontrivial deterministic patterns as well as correlated noise. Thus, any conclusion on the nature of the pattern based solely on the value of the Lempel-Ziv complexity is incomplete. In this paper, the use of the surrogate data technique is suggested to avoid spurious interpretation of this measure of complexity. The data sets considered include the uterine contraction obtained during active labor. The surrogates are generated using the amplitude adjusted fourier transform and the iterated amplitude adjusted fourier transform. The approximate entropy is used as an alternate measure to verify the results obtained.
生理数据中观察到的振荡很大程度上可归因于非线性确定性成分或非确定性成分的存在。Lempel-Ziv复杂度及其变体已成功用于量化这些振荡的规律性。在非平凡确定性模式以及相关噪声的情况下，都可以观察到复杂度的降低。因此，仅基于Lempel-Ziv复杂度的值对模式性质得出的任何结论都是不完整的。本文建议使用替代数据技术，以避免对这种复杂度度量进行虚假解释。所考虑的数据集包括活跃分娩期间获得的子宫收缩数据。替代数据是使用幅度调整傅里叶变换和迭代幅度调整傅里叶变换生成的。近似熵用作验证所得结果的替代度量。
