1. Department of Applied Mathematics and Computational Science, Thiagarajar College of Engineering, Madurai 625 015, Tamilnadu, India
2. Department of Electrical and Electronic Engineering Educators, School of Pedagogical and Technological Education, 15122 Marousi, Athens, Greece
3. Department of Mathematics, Government Arts and Science College, Pappireddipatti 636 905, Tamilnadu, India
4. Ramanujan Institute for Advanced Study in Mathematics, University of Madras, Chennai 600 005, Tamilnadu, India