1. Institute for Applied Information Processing and Communications (IAIK); Graz University of Technology; Inffeldgasse 16a; A-8010 Graz; Austria
2. Pervasive Computing Group / Institute of Networked and Embedded Systems (NES); Klagenfurt University; Lakeside B02b; A-9020 Klagenfurt; Austria
3. Computer Science Research and Development Unit; Pakistan
4. University of Cambridge Computer Laboratory; William Gates Building, 15 J.J. Thomson Ave.; Cambridge CB3 0FD; UK