In the last years, institutions and organizations have started paying attention to the semantic data technologies as a key component of their information management infrastructure. A key component in traditional information systems that is expected to have a great relevance in the Semantic Web and linked open data projects are knowledge organization systems: classifications, thesauri, list of subject headings, etc. W3C technical standards for the Semantic Web include the SKOS (Simple Knowledge Organization System) specification for encoding and tagging these knowledge representation tools. The adaptation of an existing knowledge representation system to SKOS requires the conversion and tagging of the data. This is a task that can be easily done by the staff working at libraries, archives and documentation centers, but the conversion of existing materials to SKOS is not enough. Centers need to offer the capability of exploring and using these systems in different ways: e.g. direct search for end-users. To do that, entities need to select and deploy software tools for storing, managing and querying SKOS tools using the SPARQL standard. The complexity of the SPARQL language makes necessary to think on ways to make querying easier for end-users.
This presentation describes the results of assessing two semantic repository tools – GraphDB and Virtuoso – to manage SKOS-based vocabularies and define query interfaces adapted to the relationships between concepts used in SKOS. The result of this research activity includes the design of two alternative query interfaces to help users interact with the SKOS tools when doing complex querie
