1. AGH University of Science and Technology, al. A. Mickiewicza 30, 30-059 Krakow, Poland
2. Faculty of Computer Science and Telecommunications, Cracow University of Technology, ul. Warszawska 24, 31-155 Kraków, Poland
3. Faculty of Computer Science and Information Technology, West Pomeranian University of Technology, ul. Żołnierska 49, 71-210 Szczecin, Poland