On labeling schemes for the semantic web

This paper focuses on the optimization of the navigation through voluminous subsumption hierarchies of topics employed by Portal Catalogs like Netscape Open Directory (ODP). We advocate for the use of labeling schemes for modeling these hierarchies in order to e ciently answer queries such as subsumption check, descendants, ancestors or nearest common ancestor, which usually require costly transitive closure computations. We rst give a qualitative comparison of three main families of schemes, namely bit vector, pre x and interval based schemes. We then show that two labeling schemes are good candidates for an e cient implementation of label querying using standard relational DBMS, namely, the Dewey Pre x scheme 6] and an Interval scheme by Agrawal, Borgida and Jagadish 1]. We compare their storage and query evaluation performance for the 16 ODP hierarchies using the PostgreSQL engine. Categories and Subject Descriptors H.2.3 Information Systems]: Database Management-Query Languages Ge...

• Type: Conference
• Year: 2003
• Where: WWW
• Authors: Vassilis Christophides, Dimitris Plexousakis, Michel Scholl, Sotirios Tourtounis
• Keywords: Internet Technology, Interval Based Schemes, ODP Hierarchies, Voluminous Subsumption Hierarchies, WWW 2003