Keyword extension method and system and classification corpus annotation method and system

摘要

This invention provides a keyword expansion method and system. The method comprises searching with a predetermined initial keyword to obtain current keywords used as a basis of a next search, performing loop search through keyword iteration; if a keyword error between keywords obtained in the current search and those keywords obtained in a previous search is less than a predetermined threshold, using the keywords obtained in the current search as expanded keywords of the initial keyword. With this method, the problem of manually establishing a thesaurus in the prior art may be solved. This method is a simple, accurate and efficient keyword expansion method. A method and system of automatically annotating a classified corpus is also provided. The method comprises: determining one or more initial core keywords for each class; obtaining expanded keywords for each class through expanding the initial core keywords; searching with the expanded keywords corresponding to a class to select a classified corpus and annotating the classified corpus.