1. Intelligent Networks Research Group, German Research Center for Artificial Intelligence,Kaiserslautern,D-67663
2. Cognitive and Developmental Psychology, University of Kaiserslautern-Landau,Kaiserslautern,D-67663
3. Centro de Investigação em Ciências Psicológicas, Universidade de Lisboa, Portugal,Lisboa,PT-1649-004
4. Institute for Wireless Communication and Navigation, University of Kaiserslautern-Landau,Kaiserslautern,D-67663