1. Department of Studies in Mathematics, Davangere University, Shivagangothri, Davangere 577007, India
2. Department of Engineering, University of Cambridge, Cambridge CB2 1PZ, UK
3. Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7 D, Arica 1000000, Chile
4. Faculty of Computer Science and Engineering Science, TH Koln-University of Applied Sciences, 51643 Gummersbach, Germany