关键词: 汉语分词, 上下文, 条件随机场, 词位标注, 特征模板

Abstract: Context is the necessary resource not only for obtaining linguistic knowledge in statistical linguistics but also for solving the problem in natural language processing.The performance of Chinese word segmentation has been greatly improved by word-position-based approaches in recent years.This approach treats Chinese word segmentation as a word-position tagging problem.To tag the word-position of current character needs the help of correlative context.To overcome the lack of giving the result by the subjective experience，this paper studies the contribution of above and below for Chinese word segmentation via using four word-positions and conditional random fields.Closed evaluations are performed on PKU and MSRA corpus from the second international Chinese word segmentation Bakeoff-2005，and comparative experiments are performed on different feature templates.Experimental results show that the performance by the below-context increases 13 percentage points than by the above-context.

Key words: Chinese word segmentation, context, conditional random fields, word-position tagging, feature template