Answering queries over ontologies is an important issue for the Semantic Web. Aggregate queries were widely studied for relational databases but almost no results are known for ag...
Diego Calvanese, Evgeny Kharlamov, Werner Nutt, Ca...
Applications and services that access Web data are becoming increasingly more useful and wide-spread. Current main-stream Web query languages such as XQuery, XSLT, or SPARQL, howe...
To investigate the problem of entity recognition, we deal with the creation of the so-called Entity Name System (ENS) which is an open, public back-bone infrastructure for the (Sem...
We develop a new algorithm for clustering search results. Differently from many other clustering systems that have been recently proposed as a post-processing step for Web search ...
Recent work in Ontology learning and Text mining has mainly focused on engineering methods to solve practical problem. In this thesis, we investigate methods that can substantially...