1. Department of Mathematics and Computer Science, Faculty of Science and Technology, São Paulo State University (UNESP), 19060-900 P. Prudente, SP, Brazil
2. Department of Mathematics, Federal University of Technology – Paraná (UTFPR), 86812-460 Apucarana, PR, Brazil
3. Department of Electrical and Electronics Engineering, Bandirma Onyedi Eylul University, Balikesir, Turkey
4. Department of Computer Engineering, Faculty of Engineering, Hitit University, 19030 Corum, Turkey