1. Decision Sciences Institute, Fuzhou University, Fuzhou, Fujian, P.R. China
2. School of Architecture and Engineering, Tongling University, Tongling, Anhui, P.R. China
3. Key Laboratory of Spatial Data Mining & Information Sharing of Ministry of Education, Fuzhou University, Fuzhou, Fujian, P.R. China
4. School of Electronic Information Science, Fujian Jiangxia University, Fuzhou, Fujian, P.R. China