1. Research Center Rez, Ltd., Husinec-Rez 250 68, Czech Republic e-mail:
2. Faculty of Informatics, Masaryk University, Botanická 15, Brno 612 00, Czech Republic
3. Faculty of Informatics, Masaryk University, Botanická 15, Brno 612 00, Czech Republic
4. Department of Mathematics and Physics, University of Defence, Kounicova 65, Brno 612 00, Czech Republic
5. Research Center Rez, Ltd., Husinec-Rez 250 68, Czech Republic