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Updated: Jul 6, 2026

Generation and Coherent Control of Pulsed Quantum Frequency Combs
Published on: June 8, 2018
Direction of coupling from phases of interacting oscillators: a permutation information approach
A Bahraminasab1, F Ghasemi, A Stefanovska
1Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom.
Abstract:
We introduce a directionality index for a time series based on a comparison of neighboring values. It can distinguish unidirectional from bidirectional coupling, as well as reveal and quantify asymmetry in bidirectional coupling. It is tested on a numerical model of coupled van der Pol oscillators, and applied to cardiorespiratory data from healthy subjects. There is no need for preprocessing and fine-tuning the parameters, which makes the method very simple, computationally fast and robust.
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