“…Once the user navigational behaviors are effectively characterized, it provides benefits for further Web applications such as facilitation and improvement of Web service quality for both Web-based organizations and for end-users. As a result, Web usage mining recently has become active topic for the researcher from database management, artificial intelligence, and information systems, etc (Buchner & Mulvenna, 1998;Cohen, Krishnamurthy, & Rexford, 1998;Lieberman, 1995;Ngu & Sitehelper, 1997;Perkowitz & Etzioni, 1998;Stormer, 2005;Zhou, Hui, & Fong, 2005). Meanwhile, with the benefits of great progress in data mining research, many data mining techniques such as clustering (Han,, Karypis, Kumar & Mobasher, 1998;Mobasher et al, 2002;Perkowitz & Etzioni, 1998), association rule mining (Agarwal & Srikant, 1994;Agarwal, Aggarwal, & Prasad, 1999), and sequential pattern mining (Agarwal & Srikant, 1995) are adopted widely to improve the usability and scalability of Web mining techniques.…”