1. School of Information Science and Engineering; Central South University; Changsha 410083 China
2. College of Electrical and Information Engineering; Hunan University; Changsha 410082 China
3. School of Automation; China University of Geosciences; Wuhan 430074 China
4. Smart City & Energy Promotion Unit, FUJITSU LIMITED; Tokyo 144-8588 Japan
5. Graduate School of Environmental and Energy Engineering; Waseda University; Tokyo 162-0041 Japan