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(11)

EP 1 644 855 A1

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(43) Date of publication: 12.04.2006 Bulletin 2006/15 (21) Application number: 03818146.7 (22) Date of filing: 14.07.2003

(51) International Patent Classification (IPC):  G06F 17/50(1995.01) (86) International application number: PCT/US2003/021997 (87) International publication number: WO 2005/017785 (24.02.2005 Gazette 2005/08)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR (71) Applicant: Cadence Design Systems, Inc. San Jose, CA 95134 (US)	(72) Inventors: Sheffer, Louis K. Campbell, CA 95008 (US) Yoshida, Kenji Inagi-shi Tokyo 206-0803 (JP) Abe, Yoshikuni Yokohama-shi, Kanagawa 226-0001 (JP) Fujimura, Aki Saratoga, CA 95070 (US) Pack, Robert C. Foster City, CA 94404 (US) (74) Representative: Viering, Jentschura & Partner  Steinsdorfstrasse 6 80538 München 80538 München (DE)