1. School of Information Systems, Queensland University of Technology, Brisbane, QLD 4000, Australia
2. Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
3. INESC-ID, 1000-029 Lisbon, Portugal
4. Grupo Lusíadas, Imagiology Department, 1500-458 Lisbon, Portugal
5. Human Technology Institute, University of Technology Sydney, Sydney, NSW 2007, Australia