A Semi-automatic Method Based on Statistic for Mandarin Semantic Structures Extraction in Specific Domains

This paper proposed a new method of semi-automatic extraction for semantic structures from unlabelled corpora in specific domains. The approach is statistical in nature. The extracted structures can be used for shallow parsing and semantic labeling. By iteratively extracting new words and clustering words, we get an inital semantic lexicon that groups words of the same semantic meaning together as a class. After that, a bootstrapping algorithm is adopted to extract semantic structures. Then the semantic structures are used to extract new key words and augment the semantic lexicon. The resultant semantic structures are interpreted by persons and are amenable to handediting for refinement. In this experiment, the semi-automatically extracted structures SSA provide recall rate of 84.5%.     

单线半自动闭塞区段提速旅客列车扣除系数

旅客列车提速，会改变客货列车速差，引起旅客列车扣除系数和非平行运行因通过能力的变化．通过理论研究和模拟分析，确定了单线半自动闭塞区段提速旅客列车扣除系数的变化规律和取值范围．提速旅客列车对数较少时，扣除系数波动幅度较大，反之较小．扣除系数有随旅客列车速度提高而减小的趋势．当提速旅客列车在10对以上时，扣除系数为0．8—1．1，且在0．9—1．0之间的几率较大，建议取0．85—1．15．