1. a Department of Management Science and Engineering , Akita Prefectural University, 84-4 Tsuchiya-Ebinokuti , Yulihonjo, Akita 015-0055, Japan
2. b Institute of Systems Engineering, Northeastern University , Shenyang 110004, PR China
3. c Department of Economics and Business Management , Yamagata University , Yamagata 990-8560, Japan