tailieunhanh - Báo cáo hóa học: " Research Article Univariate and Bivariate Empirical Mode Decomposition for Postural Stability Analysis"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Univariate and Bivariate Empirical Mode Decomposition for Postural Stability Analysis | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2008 Article ID 657391 11 pages doi 2008 657391 Research Article Univariate and Bivariate Empirical Mode Decomposition for Postural Stability Analysis Hassan Amoud Hichem Snoussi David Hewson and Jacques Duchene Charles Delaunay Institute FRE CNRS 2848 University of Technology of Troyes 10000 Troyes France Correspondence should be addressed to Hassan Amoud Received 22 October 2007 Accepted 7 February 2008 Recommended by Kenneth Barner The aim of this paper was to compare empirical mode decomposition EMD and two new extended methods of EMD named complex empirical mode decomposition complex-EMD and bivariate empirical mode decomposition bivariate-EMD . All methods were used to analyze stabilogram center of pressure COP time series. The two new methods are suitable to be applied to complex time series to extract complex intrinsic mode functions IMFs before the Hilbert transform is subsequently applied on the IMFs. The trace of the analytic IMF in the complex plane has a circular form with each IMF having its own rotation frequency. The area of the circle and the average rotation frequency of IMFs represent efficient indicators of the postural stability status of subjects. Experimental results show the effectiveness of these indicators to identity differences in standing posture between groups. Copyright 2008 Hassan Amoud et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Falls are a major problem for the elderly due to the resulting loss of autonomy and subsequent behavior modification related to fear of falling. Health care services worldwide are actively working on the issue of falls for both medical and social reasons. For instance in France alone the number of deaths .