Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 16, 2015 | Published
Journal Article Open

On the convergence and accuracy of the cardiovascular intrinsic frequency method


In this paper, we analyse the convergence, accuracy and stability of the intrinsic frequency (IF) method. The IF method is a descendant of the sparse time frequency representation methods. These methods are designed for analysing nonlinear and non-stationary signals. Specifically, the IF method is created to address the cardiovascular system that by nature is a nonlinear and non-stationary dynamical system. The IF method is capable of handling specific nonlinear and non-stationary signals with less mathematical regularity. In previous works, we showed the clinical importance of the IF method. There, we showed that the IF method can be used to evaluate cardiovascular performance. In this article, we will present further details of the mathematical background of the IF method by discussing the convergence and the accuracy of the method with and without noise. It will be shown that the waveform fit extracted from the signal is accurate even in the presence of noise.

Additional Information

© 2015 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. Received: 7 October 2015; Accepted: 17 November 2015; Published 16 December 2015. Data accessibility. Data used in this study can be downloaded from http://dx.doi.org/10.5061/dryad.21q9m. Authors' contributions. P.T. conceived of the study, carried out the modelling, programming and mathematical analysis of the method, carried out part of the design of the numerical examples and drafted the manuscript; T.Y.H. coordinated the mathematical part of the study, helped draft the manuscript and supervised the mathematical analysis of the method; D.G.R. helped draft the manuscript, and revised the manuscript critically for important intellectual content; N.M.P. carried out part of the design of the numerical examples, interpreted the physiological meaning of the method, correlated the main parameters of the method with physiological parameters, collected relevant clinical data, coordinated the general scope of the study and helped draft the manuscript. All authors gave final approval for publication. We declare we have no competing interests. This work was supported by NSF grant no. DMS-1318377. The authors are grateful to Sean Brady and Frank Becking for their constructive comments regarding the composition and presentation of the manuscript. The authors are also grateful to anonymous reviewers as their comments and questions definitely improved the quality of the manuscript.

Attached Files

Published - rsos150475.pdf


Files (844.6 kB)
Name Size Download all
844.6 kB Preview Download

Additional details

August 20, 2023
August 20, 2023