1. China University of Geosciences,School of Geography and Information Engineering,Wuhan,China,430079
2. Central China Normal University,Hubei Research Center for Educational Informationization/Faculty of Artificial Intelligence in Education,Wuhan,China,430079
3. Wuhan University,School of Computer Science,Wuhan,China,430072
4. City University of Hong Kong,Department of Electronic Engineering,Hong Kong,China