1. School of Electrical Engineering, Rajamangala University of Technology, Rattanakosin,Faculty of Engineering,Salaya,Nakhon Pathom,Thailand
2. School of Electrical Engineering, Rajamangala University of Technology Suvarnabhumi,Faculty of Engineering and Architecture,Nonthaburi,Thailand
3. School of electrical engineering, Institute of Engineering, Suranaree University of Technology,Nakhon Ratchasima,Thailand