1. School of Computer Science and Educational Software; Guangzhou University; Guangzhou 510006 China
2. Guangdong Provincial Engineering; Technology Research Center for Mathematical Educational Software; Guangzhou Guangdong 510006 China
3. School of Energy Science and Engineering; University of Electronic Science and Technology of China; Chengdu 611731 China
4. Lab Center; Guangzhou University; Guangzhou 510006 China