Copyright 1998,1999 by Naohiko ShimizuAll rights reserved. Contact information: Dr. Naohiko Shimizu School of Engr. Tokai Univ. 1117 Kitakaname Hiratsuka Kanagawa 259-1292 Japan email: nshimizu@ keyaki . cc.u-tokai.ac.jp URL: http://shimizu-lab.et.u-tokai.ac.jp