1. Department of the Built Environment, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; CORE Consult, 69 Derwent Drive, Maidenhead, Berkshire SL6 6LE, UK
2. Department of the Built Environment, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands