[1] Univ Warsaw, Inst Informat, Warsaw, Poland
[2] Tech Univ Kosice, Fac Elect Engn & Informat, Kosice, Slovakia
[3] Univ Campania Luigi Vanvitelli, Dipartimento Matemat & Fis, Caserta, Italy
[4] Casimir Great Univ Bydgoszcz, Inst Comp Sci, Bydgoszcz, Poland