U.S. Patent May 22, 2007 Sheet 1 M4 US 7,221,972 B2 \ cm? cor \ \@2/ 50 6 @ 8 9 2 i 0 5 0@\ 03 $@=29E5o0 0$3:29hwEo mw 63891 mow omw\\ hmwD mo toBEm? v059m