Error:URL rejected: Malformed input to a URL function Correspondingauthor.tel.: 886 3 537 4281x6583;fax: 886 4 2422 6527.e Mailaddress:kai@chu.edu.tw(k.w.li).0925 7535/seefrontmatter2003elsevierltd.allrightsreserved.doi:10.1016/j.ssci.2003.08.006 Safet - PowerPoint Presentations and PDF Documents