1. College of Computer, Qinghai Normal University, Xining 810008, China
2. Key Laboratory of Tibetan Information Processing, Ministry of Education, Xining 810008, China
3. Key Laboratory of Tibetan Information Processing and Machine Translation in QH, Xining 810008, China
4. Teaching and Research Department of Basic Courses, Qinghai University, Xining 810008, China
5. State Key Laboratory of Tibetan Intelligent Information Processing and Application, Xining 810008, China