Mei T.Hsu W.H.Luo J.2019-07-102019-07-1020101070986Xhttps://scholars.lib.ntu.edu.tw/handle/123456789/412950This special issue presents a concise reference of state-of-the-art efforts in the attempts for knowledge discovery in large-scale community-contributed multimedia, and in particular the opportunities and challenges in this nascent arena. The guest editors have selected five articles that represent ways to exploit the user-contributed photos and videos for several applications and that identify the theoretical challenges associated with managing such multimedia data. ? 2010 IEEE.community-contributed multimedia; graphics; guest editors' introduction; knowledge discovery; multimedia content analysis; social mediajournal article10.1109/MMUL.2010.822-s2.0-78649296712