Object Link Structure in the Semantic Web

Lots of RDF data have been published in the Semantic Web. The RDF data model, together with the decentralized linkage nature of the Semantic Web, brings object link structure to the worldwide scope. Object links are critical to the Semantic Web and the macroscopic properties of object links are helpful for better understanding the current Data Web. In this paper, we propose a notion of object link graph (OLG) in the Semantic Web, and analyze the complex network structure of an OLG constructed from the latest dataset (FC09) collected by the Falcons search engine. We find that the OLG has the scale-free nature and the approximate effective diameter of the graph is small compared to its scale, which are also consistent with the experimental result based on our last year’s dataset (FC08). The amount of RDF documents and objects by Falcons both doubled during the past year, but the object link graph remains the same density while the diameter is getting shrinking. We also repeat the complex network analysis on the two largest domainspecific subsets of FC09, namely Bio2RDF(FC09) and DBpedia(FC09). The results show that both Bio2RDF(FC09) and DBpedia(FC09) have low density in object links, which contribute to the low density of object links in FC09.