Conference on information and knowledge management and co-located workshop : CIKM'12, proceedings of the 21st ACM international conference ; BooksOnline'12, CDMW'12, CloudDB'12, CrowdSens'12, DOLAP'12, DTMBIO'12, DUBMMSM'12, ESAIR'12, IKM4DR'12, MIXHS'12, PIKM'12, PLEAD'12, SHB'12, Web-KR'12, & WIDM'12 ; Maui, HI, USA, Oct. 29-Nov. 2, 2012 (ACM - Association for Computing Machinery, 2012)