Volume 80, Number 6, December 2007
Article Number 68004
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
Published online 13 November 2007
EPL, 80 (2007) 68004
DOI: 10.1209/0295-5075/80/68004

Automated detection of time-dependent cross-correlation clusters in nonstationary time series

C. Rummel1, G. Baier1, 2 and M. Müller1, 3

1  Facultad de Ciencias, Universidad Autónoma del Estado de Morelos - 62209 Cuernavaca, México
2  Manchester Interdisciplinary Biocentre, The University of Manchester - 131 Princess Street, Manchester, UK
3  EML Research - Schloss-Wolfsbrunnenweg 33, 69118 Heidelberg, Germany

received 7 August 2007; accepted in final form 19 October 2007; published December 2007
published online 13 November 2007

A novel method for the detection of cross-correlation clusters in multivariate time series is suggested. It is based on linear combinations of the eigenvectors corresponding to the largest eigenvalues of the equal-time cross-correlation matrix. The linear combinations are found in a systematic way by maximizing an appropriate distance measure. The performance of the algorithm is evaluated with a flexible time-series$\hbox{--} $based test framework for cluster algorithms. Attribution errors are investigated quantitatively in model data and a comparison with three alternative approaches is made. As the algorithm is suitable for unsupervised online application we demonstrate its time-resolved use in the example of cluster detection in time series from human electroencephalogram.

87.19.La - Neuroscience.
05.45.Tp - Time series analysis.
89.75.Fb - Structures and organization in complex systems.

© EPLA 2007