1. Department of MathematicsNational Institute of Technology AgartalaAgartala799046India
2. Department of Electrical EngineeringNational Institute of Technology SilcharSilchar788010India
3. Graduate School of Engineering, Hiroshima University1‐4‐1 KagamiyamaHigashi‐Hiroshima739‐8527Japan
4. School of Electrical Engineering, Korea UniversityAnam‐Dong 5‐Ga, Sungbuk‐GuSeoul136‐701Republic of Korea