1. School of Mathematics and Information Science, Henan Polytechnic University, Jiaozuo 454000, P. R. China
2. School of Management Engineering, Qingdao University of Technology, Qingdao 266525, P. R. China
3. Institute of Operations Research, School of Management, Qufu Normal University, Rizhao 276826, P. R. China
4. Department of Mathematics and Information, Ludong University, Yantai 264025, P. R. China