Theobald, AnjaWeikum, GerhardSchöning, HaraldRahm, Erhard2019-11-142019-11-1420033-88579-355-5https://dl.gi.de/handle/20.500.12116/30054Query languages for XML such as XPath or XQuery support Boolean re- trieval where a query result is a (possibly restructured) subset of XML elements or entire documents that satisfy the search conditions of the query. Web search engines, on the other hand, are based on the ranked retrieval paradigm, but do not consider the additional information and rich annotations provided by the structure of XML documents and their element names. Furthermore, web search engines have very little "semantic" data and are thus unable to cope with ambiguous search terms. Ontological knowledge and appropriate index structures are necessary for semantic similarity search on XML data extracted from the web. In this paper we present a powerful ontology index which supports domain-specific semantic similarity search with a new measure for expressing the relevance of query results.enText/Conference Paper1617-5468