Affiliation: | 1. IBM Research—Zurich, S?umerstrasse 4, CH‐8803 Rüschlikon (Switzerland);2. Current address: Konrad‐Zuse‐Zentrum für Informationstechnik Berlin, Takustrasse 7, D‐14195 Berlin (Germany);3. Philip Morris International R&D, Quai Jeanrenaud 5, CH‐2000 Neuchatel (Switzerland);4. University of Twente, Faculty EEMCS, PO Box 217, NL‐7500 AE Enschede (The Netherlands) |