... alternatives to the341 Independent Component Analysis. Aapo Hyv¨arinen, Juha Karhunen, Erkki OjaCopyright 2001 John Wiley & Sons, Inc.ISBNs: 0-4 7 1-4 0540-X (Hardback); 0-4 7 1-2 213 1-7 (Electronic)342METHODS ... TimeStructureThe model of independent component analysis (ICA) that we have considered sofar consists of mixing independent random variables, usually linearly. In manyapplications, however, what ... have identical autocovariances (i.e., identicalpower spectra), they cannot be estimated by the methods using time-lagged covari-ances only. This is in contrast to ICA using higher-order information,...