MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Information Systems' source. Sat, 10 Oct 2009 19:32:15 +0100 http://www.medworm.com/index.php?rid=1570471&cid=s_37312_21_f&fid=37312&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18496587%26dopt%3DAbstract Authors: Wang Q, Megalooikonomou V We propose a dimensionality reduction technique for time series analysis that significantly improves the efficiency and accuracy of similarity searches. In contrast to piecewise constant approximation (PCA) techniques that approximate each time series with constant value segments, the proposed method--Piecewise Vector Quantized Approximation--uses the closest (based on a distance measure) codeword from a codebook of key-sequences to represent each segment. The new representation is symbolic and it allows for the application of text-based retrieval techniques into time series similarity analysis. Experiments on real and simulated datasets show that the proposed technique generally outperforms PCA techniques in clustering and similarity searches. PM... Information Systems journals http://www.medworm.com/rss/comments.php?id=1570471 Sat, 01 Mar 2008 05:00:00 +0100 1570471