András Horváth is Associate Professor at the University of Turin, Italy. His research interests include analysis and optimization of stochastic models with applications in production systems, service operations, communication networks and systems biology. Miklós Telek is a professor in the Department of Networked Systems and Services at Budapest University of Technology and Economics, Hungary, where he currently heads the Information Systems Research Group of the Hungarian Research Network. His research interests include stochastic performance modeling, analysis and optimization of computer and communication systems.