Ambient Intelligence [electronic resource] : Second International Joint Conference on AmI 2011, Amsterdam, The Netherlands, November 16-18, 2011. Proceedings / edited by David V. Keyson, Mary Lou Maher, Norbert Streitz, Adrian Cheok, Juan Carlos Augusto, Reiner Wichert, Gwenn Englebienne, Hamid Aghajan, Ben J. A. Kröse.