Information Retrieval Technology : 5th Asia Information Retrieval Symposium, AIRS 2009, Sapporo, Japan, October 21-23, 2009, Proceedings - Gary Geunbae Lee, Dawei Song, Chin-Yew Lin, Akiko Aizawa, Kazuko Kuriyama, Masaharu Yoshioka, Tetsuya Sakai ((Lecture Notes in Computer Science))