1. EVSE, Faculty of Engineering, University of Regina, Regina, Saskatchewan, Canada, S4S 0A2.
2. Phone: 306-585-4095; Fax: +1-306-585-4855; E-mail: gordon.huang@uregina.ca
3. Chinese Research Academy of Environmental Science, North China Electric Power University, Beijing, China 100012-102206.
4. Faculty of Engineering, Dalhousie University, Halifax, Nova Scotia, Canada, B3J 1Z1.