针对RDF含相对量词模糊查询问题,提出支持分组机制的相对量词RDF模糊查询方法.利用语言层次结构理论,构造语言层次结构表,通过在FILTER子句中增加模糊条件并调用GROUPBY和HAVING子句实现特定属性上的分组操作,实现对SPARQL语法的扩展.分析了两种典型情况下的RDF相对量词模糊查询问题,给出将扩展的模糊SPARQL查询转换为标准SPARQL查询的处理方法,从而可利用现有的SPARQL查询引擎完成RDF基于相对量词的模糊查询处理.实验系统及相应的实验结果验证了所提方法的可用性.
In order to deal with the fuzzy queries of RDF with relative quantifiers, an approach of querying RDF with relative quantifiers was proposed, which can also support grouping mechanism. A linguistic hierarchy table reflecting various accuracies of fuzzy constraints was first constructed. An extended SPARQL syntax was hereby proposed by introducing fuzzy conditions in FILTER clause and calling GROUP BY and HAVING clauses to accomplish grouping operations over specific attributes. Two typical cases of fuzzy RDF querying with relative quantifiers were analyzed. On the basis, how to translate fuzzy SPARQL queries into classic SPARQL queries was investigated so that the existing SPARQL implementations can handle the fuzzy RDF querying with relative quantifiers. Finally, an experimental system is developed and the experimental results show the feasibility of the proposed approach.