Daniel Roggen Alberto Calatroni Kilian Förster Gerhard Tröster Paul Lukowicz David Bannach Alois Ferscha Marc Kurz Gerold Hölzl Hesam Sagha Hamidreza Bayati José del R. Millán Ricardo Chavarriaga Activity Recognition in Opportunistic Sensor Environments. 173-174 2011 7 Procedia CS http://dx.doi.org/10.1016/j.procs.2011.09.003 db/journals/procedia/procedia7.html#RoggenCFTLBFKHSBMC11