With the rapid development in WWW, web server on internet has accumulated a large number of web logs. Web usage mining is one of the hot current studies and belongs to a multi-interdisciplinary area of research, which involves database technology, artificial intelligence, neural network, pattern recognition, statistics, fuzzy sets, rough sets and many other disciplines. After mining the web logs, we can discover some deep-level knowledge and rules-the navigation behavior and interests of web users. The know...