1. Inertia Technology, Offenbachlaan 2, 7522 JT Enschede, The Netherlands
2. Ambient Systems, Colosseum 15d, 7521 PV Enschede, The Netherlands
3. Pervasive Systems Research Group, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
4. Novay, Brouwerijstraat 1, 7523 XC Enschede, The Netherlands