Adapting Property Path for Polynomial-Time Evaluation and Reasoning on Semantic Web

• Published in: Transactions of Tianjin University Vol. 19; no. 2; pp. 130 - 139
• Main Author: 姜洋 冯志勇 王鑫 饶国政
• Format: Journal Article
• Language: English
• Published: Heidelberg Tianjin University 01.04.2013; School of Computer Science and Technology, Tianjin University, Tianjin 300072, China
• Subjects: Engineering; Humanities and Social Sciences; Mechanical Engineering; multidisciplinary; Science; 多项式时间; 推理; 正则表达式; 物业; 等价关系; 评价; 语义Web; 路径查询; path; efficiency; semantics; graph; reasoning
• ISSN: 1006-4982; 1995-8196
• DOI: 10.1007/s12209-013-2137-y

Property path is the latest navigational extension of the standard query language SPARQL 1.1 for the Semantic Web. However, in the existing SPARQL query systems which support property path, the query efficiency is very low and does not support reasoning. This paper proposes a new existential semantics which has polynomial-time evaluation complexity and an equivalent relationship with the current semantics, and transforms the property path ex- pressions to the extended nested regular expressions based on the existential semantics and proves the semantic equivalence after the transformation considering the RDFS semantics. The property path query engine is achieved by implementing the nested regular expressions algorithm and the transformation rules from the property path expressions to the nested regular expressions, which maintains the syntax simplicity of property path and the goal-oriented poly- nomial-time reasoning to avoid computing the RDF graph closure. The experiment results not only show the characteristics of query engine based on the existential semantics in efficiency and reasoning, but also further validate the equivalence between the results based on current semantics and those based on the existential semantics for property path after the removal of duplicate values.