2011-04-24 EM algorithm em http://convexbrain.sourceforge.jp/cgi-bin/wifky.pl?p=EM%A5%A2%A5%EB%A5%B4%A5%EA%A5%BA%A5%E0GMM http://convexbrain.sourceforge.jp/cgi-bin/wifky.pl?p=GMMhttp://www.cc.gatech.edu/~dellaert/em-paper.pdfhttp://www.eb.waseda.ac.jp/murata/noboru.murata/slide/mura03_fit.pdf