1. University of California, Santa Barbara, USA. E-mail: jano@geog.ucsb.edu
2. Wright State University, Dayton, OH, USA. E-mail: pascal.hitzler@wright.edu
3. The University of Auckland, New Zealand. E-mail: b.adams@auckland.ac.nz
4. Raytheon BBN Technologies, MD, USA. E-mail: dkolas@bbn.com
5. University of Notre Dame, Notre Dame, IN, USA. E-mail: cvardema@nd.edu