Prof. Agassi Z. Melikov is a professor in the Dept. of Teletraffic Theory at the Institute of Cybernetics of the National Academy of Sciences of Azerbaijan and a professor in the Dept. of Information Technologies at Baku State University, Azerbaijan. His research interests include teletraffic and queuing theory and their applications. Prof. Leonid A. Ponomarenko is a senior scientific researcher in the International Scientific-Education Center of the National Academy of Science of Ukraine, and he is a professor in the Dept. of Project Management in Kiev National University of Civil Engineering and Architecture. His areas of interests include mathematical modeling, the theory of queues with priorities, economics, logic and computer communications. He was awarded the state prize of Ukraine in Science and Engineering in 2002.