Indexing Scheme for Keyword Search over Semantic Web Documents

The semantic Web is an extension of the current Web in which information are given well-defined meaning to enable computers and people to work in cooperation. Many ontology languages such as RDF and OWL describe metadata on the semantic Web. Metadata can be used to retrieve related information through the inference more accurately and simply. RDF is a language for representing metadata. An enormous number of keywords on the semantic Web are very important to make practical applications of the semantic Web because most users prefer to search with keywords. In this paper, we classify queries with keyword conditions into three patterns and propose indexing techniques for keyword-search considering both metadata and ontology. The proposed indexing techniques aim at efficient process of keyword-search for RDF/S documents. There are many studies about keyword-search techniques based on XML RDF is different from XML on the Web. So, there is a need for query processing which is appropriate to RDF. And we propose a structure of table for storing RDF schema information. We propose a few ranking schemes for RDF/S documents. The schemes can be used to determine a sequence of query results according to predefined importance of resources.