1. Department of Mathematics, Faculty of Science , King Mongkut’s University of Technology Thonburi (KMUTT), 126 Pracha Uthit Rd., Bang Mod,Thung Khru, Bangkok 10140 , Thailand
2. National Institute of Technology , Surat - 395007 Gujarat, India
3. Department of Mathematics, Faculty of Science , King Mongkut’s University of Technology Thonburi (KMUTT) , 126 Pracha Uthit Rd., Bang Mod,Thung Khru, Bangkok 10140 , Thailand