关键词: 本体库, 垂直搜索引擎, 语义扩展, 中国气象数据网

Abstract: As the progress is both time and effort consuming to build a Web ontology-based vertical search engine by collating the descriptors and the relation for each descriptor, it is not suitable for most of website search system but search engine. And thus, the Web retrieval system remains the character-matching search function which lacks of segmentation, semantic query expansion, ranking the results by semantic relatedness and so on. To solve those problems, a vertical search engine based on a concise ontology has been designed and implemented. Taking the case of China Meteorological Data Service Center（CMDC）, firstly, a concise ontology library will be built by protégé with the list of website navigation, which is used to design a vertical search engine on the frame of Lucene. Meanwhile, the segmentation algorithm（IKanalyzer） is used for this system in the progress of indexing and searching. After that, the semantics is expanded by the semantic analysis techniques（Jena）. Remarkably, the correlation degree of the semantic expansion has been calculated used as the weight value of each segmented words. This is used to rank the search result by the TF-IDF algorithm. The results show that the system can be used to expand and recommend the relative search content, and there is a great promotion of both precision and recall of results within these improvements.

Key words: ontology, vertical search engine, semantic expansion, China Meteorological Data Service Center（CMDC）