1. Swinburne University of Technology; Hawthorn Campus; Melbourne VIC 3122 Australia
2. Department of Computing; The Open University; Milton Keynes MK7 6AA UK
3. Distributed Systems Group; Vienna University of Technology; Argentinierstrasse 8/184-1 Wein A-1040 Austria
4. University of Bradford; BD7 1DP Bradford UK
5. Chinese University of Geosciences; Wuhan China
6. School of Computing Science; Newcastle University; NE1 7RU Newcastle upon Tyne UK