research interests
My interests lie in the areas of knowledge representation and databases. Specifically, knowledge-mediated access to information (i.e., using a conceptual schema (or an ontology) over the data sources, with mappings connecting ontology elements to the actual data, for querying purposes) which I aim to address from both, theoretical and applied perspectives.
The main focus of my current Ph.D. research is reuse of relational sources in the context of knowledge-mediated
data access. I am tackling the problem in two phases:
— extracting semantics hidden in the relational sources by
wrapping them by means of an ontology;
— understanding the methodology for semantic enrichment of
such extracted ontologies.
For the first part, we have developed an automatic procedure for extracting from a relational database its conceptual schema, where the semantic mapping between the database and its conceptualisation is captured by associating views over the data source to each element of the extracted ontology. We have shown that our technique is an equivalence preserving schema transformation, which means that queries expressed over the extracted ontology can be evaluated by simply expanding the generated views. The approach is implemented in the prototype system OntoSynt. The online demo is available here. More information on ontology extraction is available at our wiki. For further technical details please refer to my publications or contact me.
Currently we are looking at the problem of accessing the data sources using the enriched ontology. As a starting point, we have chosen to rely on query rewriting techniques, and in particular on query reformulation algorithm for DL-Lite family of Description Logics. In parallel, we are also studying Beth's definability property for queries and views. More information can be found in my recent study plan.