Advances in Spatial and Temporal Databases : 12th International Symposium, SSTD 2011, Minneapolis, MN, USA, August 24-26, 2011. Proceedings - Dieter Pfoser, Yufei Tao, Kyriakos Mouratidis, Mario A. Nascimento, Mohamed Mokbel, Shashi Shekhar, Yan Huang ((Lecture Notes in Computer Science))