1. Department of Mathematics Applications and Methods for Artificial Intelligence, Faculty of Applied Mathematics, Silesian University of Technology, 44-100 Gliwice, Poland
2. Institute of Energy and Fuel Processing Technology, 41-803 Zabrze, Poland
3. Department of Electrical, Electronics and Informatics Engineering, University of Catania, Viale A. Doria 6, 95125 Catania, Italy