Barnes S J K, Bjerkan J, Clemson P T, Newman J, Stefanovska A
Physics Department, Lancaster University, Lancaster LA1 4YB, United Kingdom.
Department of Mathematics and Statistics, University of Exeter, Exeter, United Kingdom.
Chaos. 2024 Jul 1;34(7). doi: 10.1063/5.0202865.
Coherence measures the similarity of progression of phases between oscillations or waves. When applied to multi-scale, nonstationary dynamics with time-varying amplitudes and frequencies, high values of coherence provide a useful indication of interactions, which might otherwise go unnoticed. However, the choice of analyzing coherence based on phases and amplitudes (amplitude-weighted phase coherence) vs only phases (phase coherence) has long been seen as arbitrary. Here, we review the concept of coherence and focus on time-localized methods of analysis, considering both phase coherence and amplitude-weighted phase coherence. We discuss the importance of using time-localized analysis and illustrate the methods and their practicalities on both numerically modeled and real time-series. The results show that phase coherence is more robust than amplitude-weighted phase coherence to both noise perturbations and movement artifacts. The results also have wider implications for the analysis of real data and the interpretation of physical systems.
相干性衡量振荡或波之间相位进展的相似性。当应用于具有随时间变化的幅度和频率的多尺度、非平稳动力学时，高相干值提供了相互作用的有用指示，否则这些相互作用可能会被忽视。然而，长期以来，基于相位和幅度（幅度加权相位相干）与仅基于相位（相位相干）来分析相干性的选择一直被视为是任意的。在此，我们回顾相干性的概念，并关注时间局部化分析方法，同时考虑相位相干和幅度加权相位相干。我们讨论使用时间局部化分析的重要性，并在数值建模和实际时间序列上说明这些方法及其实用性。结果表明，相位相干在抵抗噪声扰动和运动伪影方面比幅度加权相位相干更稳健。这些结果对实际数据的分析和物理系统的解释也具有更广泛的意义。
