1. Ghent University, TELIN-IPI-IMINDS, Sint-Pietersnieuwstraat 41, Ghent, Belgium
2. Ghent University, TELIN-IPI-IMINDS, Sint-Pietersnieuwstraat 41, Ghent, BelgiumbAmbient Intelligence Research Lab, David Packard Building, Stanford, California 94305–9515, United States