1. Cologne Institute for Information Systems (CIIS), University of Köln, Pohligstraße 1, 50969 Cologne, Germany
2. MIT Center for Collective Intelligence, Cambridge, MA 02142, USA
3. Galaxylabs, Laurenzenvorstadt 69, 5000 Aarau, Switzerland
4. Departments of Mathematics and Architecture, University of Texas at San Antonio, One UTSA Circle, San Antonio, TX 78249, USA