1. Department of Mathematical Sciences, Kent State University, Kent, OH, USA
2. Department of Communications and Networking, Aalto University, Espoo, Finland
3. Faculty of Natural Sciences, Duy Tan University, Da Nang, Vietnam
4. Department of Mathematics, Banaras Hindu University, Varanasi, India
5. Centre of Excellence in Econometrics, Chiang Mai University, Chiang Mai, Thailand