1. Associate Professor, Dept. of Mathematics, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India.
2. Senior Research Scholar, Dept. of Mathematics, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302, India (corresponding author).
3. Professor, LR2E Laboratory Quartz EA 7393, Ecole Supérieure d’Ingénieurs en Génie Electrique, Productique et Management Industriel, 13 Blvd. de l’Hautil, Cergy 95092, France.