With the advance of Semantic Web and development of Linked Data, the scale of knowledge graphs has surged dramatically. On the one hand, RDF graph is a mainstream data model of the knowledge graph. On the other hand, property graphs are widely ...

In this paper, we analyze some basic features of SPARQL queries from practical world in a statistical way. In particular, we focus on three statistic features including the occurrence frequency of triple patterns, fragments, and well-designed patterns ...

Resource Description Framework RDF is a standard data model of the Semantic Web, and it has been widely adopted in various domains in recent years for data and knowledge representation. Unlike queries on relational databases, most of queries applied on ...

This paper presents an automata-based algorithm for answering the \emph{provenance-aware} regular path queries (RPQs) over RDF graphs on the Semantic Web. The provenance-aware RPQs can explain why pairs of nodes in the classical semantics appear in the ...

The optimization effect on large-scale RDF data is not statisfactory using the existing algorithms based on cost models. This paper presents the Run-time Optimization of SPARQL queries (ROS), and describes the join graphs and the index structures for ...