1. The School of Geo-Science and Info-Physics, Central South University, Changsha 410006, China
2. Department of Natural Resources, Faculty of African Postgraduate Studies, Cairo University, Giza 12613, Egypt
3. Faculty of Letters and Humanities of Sousse, University of Sousse, FLSHS-LR, Sousse 13ES11, Tunisia
4. Department of Computer Science, Hunan University, Changsha 410082, China