1. Department of Information and Communication Technology, Prince of Songkla University, Phuket Campus, Phuket 83120, Thailand
2. Department of Computer Science, University of Alabama, Tuscaloosa, AL 35487, USA
3. Sandia National Laboratories, 7011 East Avenue, Livermore, CA 94550-9610, USA
4. Department of Civil and Computer Engineering, University of Rome ‘Tor Vergata’, Roma 00173, Italy