1. Material Management and Support College, Armed Police Force Engineering University, Xi’an, China
2. Department of Information and Communication, Police officer college of Armed Police Force, Chengdu, China
3. Basic Department, Police officer college of Armed Police Force, Chengdu, China
4. School of Mathematical Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, UKM Bangi, Selangor, Malaysia