1. School of Information, University of Michigan, Ann Arbor, MI, USA and Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany
2. University of Strathclyde, Glasgow, United Kingdom
3. Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin, Germany and Fraunhofer FIT, Sankt Augustin, Germany
4. University of Glasgow, Glasgow, United Kingdom
5. Technical University of Darmstadt, Darmstadt, Germany and Telecom-Paris (IP-Paris), Paris, France
6. School of Information, University of Michigan, Ann Arbor, MI, USA