Zhang, Kun, Key Laboratory of Island Tourism Resource Data Mining and Monitoring, Ministry of Culture and Tourism, Hainan Tropical Ocean University, Sanya 572022, Hainan Province, China; School of Information Science and Technology, Hainan Normal University, Haikou 571158, Hainan Province, China; Education Center of MTA, Hainan Tropical Ocean University, Sanya 572022, Hainan Province, China, China