广东省自然科学基金(the Natural Science Foundation of Guangdong Province of China under Grant No.04020079);吉林大学符号计算与知识工程教育部重点实验室开放课题(Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education No.93K-17-2006-03);华南理工大学自然科学基金(Natural Science Foundation of South China University of Technology No.B13-E5050190)