Towards Federated Search Based on Web Services

Some emerging trends in the recent development of the WWW can be observed. These trends are technical, like Web Services, as well as semantic, like the integration of ontologies. We propose an architecture for a new kind of federated search system, which takes these aspects and new developments into account. A major challenge in this context is to cope with portals and the data sources behind the portals, the so-called “Deep Web”. One component of the proposed architecture is the service mediator, which generates wrapper classes and additional files to make portals accessible as Web Services. Other components are an onotology server, which provides Web Service based access to different ontologies and an XML Filter server that converts different source formats to XML. This loosely coupled architecture supports federated search on semistructured data and the evaluation of semantic join operations.