Recurrence (Quantification) Analysis (RQA) is a nonlinear data analysis technique used for studying dynamical systems. It can be applied to any time series coming from a dynamical system that repeats itself (conservative system) – most of the real-world complex phenomena fall into this category. Recurrence plot is a visual representation of a dynamical process. RQA measures quantify meaningful properties of the system (kind of organization, predictability, stability, etc.).
Recurrence analysis is intuitively simple: if we conceptualize time as 1D line, we can make a 2D pattern representing “meetings” between points in time, a “meeting” occurs when the system is in the same state for both time points. It is also well-grounded in dynamical systems theory (starting point: Poincaré recurrence theorem).
I want to learn RQA, what do I do?
Cross-recurrence Quantification Analysis in R tutorial
Very good, clean and efficient implementation of RQA techniques is a part of DynamicalSystems.jl package for Julia (highly recommended).
A comprehensive implementation of most standard recurrence analysis techniques and supplementary heuristics can be found in R in cRQA package. (Not so efficient for larger volumes of data.)
Demos
RQA plots online: https://hill.psych.uw.edu.pl/rqa_js/
Live RQA demo on human motion (webcam required): https://hill.psych.uw.edu.pl/frame_diff_rqa/
Who do I ask for help?