1. Department of Mathematics, Babeş-Bolyai University Cluj-Napoca, Cluj-Napoca, Romania
2. Academy of Romanian Scientists, Bucharest, Romania
3. Department of Business, Babeş-Bolyai University Cluj-Napoca, Cluj-Napoca, Romania
4. Research Center for Interneural Computing, China Medical University, Taichung, Taiwan
5. Department of Applied Mathematics, National Sun Yat-sen University, Kaohsiung, Taiwan