1. Department of Mathematical Sciences, Shahid Behesti University, 1983963113 Evin, Tehran, I. R. Iran
2. Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 8, 616 00 Brno, Czech Republic
3. Centre for Information Technologies and Applied Mathematics, University of Nova Gorica, Vipavska Cesta 13, 5000 Nova Gorica, Slovenia