Semantic search engines based on data integration systems

As the use of the World Wide Web has become increasingly widespread, the business ofcommercial search engines has become a vital and lucrative part of the Web. Search engines arecommon place tools for virtually every user of the Internet; and companies, such as Google andYahoo!, have become household names. Semantic Search Engines try to augment and improvetraditional Web Search Engines by using not just words, but concepts and logical relationships.In this chapter a relevant class of Semantic Search Engines, based on a peer-to-peer, dataintegration mediator-based architecture is described.The architectural and functional features are presented with respect to two projects, SEWASIEand WISDOM, involving the authors. The methodology to create a two level ontology and queryprocessing in the SEWASIE project are fully described.