Querying Semantic Web Resources Using TRIPLE Views

Resources on the Semantic Web are described by metadata based on some formal or informal ontology. It is a common situation that casual users are not familiar with a domain ontology in detail. This makes it difficult for such users (or their user tools) to formulate queries to find the relevant resources. Users consider the resources in their specific context, so the most straightforward solution is to formulate queries in an ontology that corresponds to a user-specific view. We present an approach based on multiple views expressed in ontologies simpler than the domain ontology. This allows users to query heterogeneous data repositories in terms of multiple, relatively simple, view ontologies. Ontology developers can define such view ontologies and the corresponding mapping rules. These ontologies are represented in Semantic Web ontology languages such as RDFS, DAML+OIL, or OWL. We present our approach with examples from the e-learning domain using the Semantic Web query and transformation language TRIPLE.