1. Institute of Automation, University of Bremen, Otto Hahn Allee NW1, D-28359 Bremen, Germany. Tel.: ; Fax.: +49 421 218 4596; E-mail: ivlev@iat.uni-bremen.de
2. Development Engineer for Control Technique and Automation, Team: LTMR, Rheinmetall-Defence-Electronics, Brüggeweg 54, 28309 Bremen, Germany. Tel.: ; Fax.: +49 421 457 1759; E-mail: martens.c@rheinmetall-de.com