1. Department of Geography, National Taiwan University, Taipei , No. 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan (ROC)
2. School of Public Policy and Management, Tsinghua University, 1 Qinghuayuan, Haidai District, Beijing, China
3. School of Government and Public Policy, University of Arizona, AZ85721-0027, Tucson, U.S.A