@conference {113,
	title = {Approximate Instance Retrieval on Ontologies},
	booktitle = {Database and Expert Systems Applications, 21st International Conference, DEXA 2010},
	volume = {6261},
	year = {2010},
	pages = {503{\textendash}511},
	publisher = {Springer},
	organization = {Springer},
	address = {Bilbao, Spain},
	abstract = {<p class="rtejustify">With the development of more expressive description logics (DLs) for the Web Ontology Language OWL the question arises how we can properly deal with the high computational complexity for effi- cient reasoning. In application cases that require scalable reasoning with expressive ontologies, non-standard reasoning solutions such as approximate reasoning are necessary to tackle the intractability of reasoning in expressive DLs. In this paper, we are concerned with the approximation of the reasoning task of instance retrieval on DL knowledge bases, trading correctness of retrieval results for gain of speed. We introduce our notion of an approximate concept extension and we provide implementations to compute an approximate answer for a concept query by a suitable mapping to efficient database operations. Furthermore, we report on experiments of our approach on instance retrieval with the Wine ontology and discuss first results in terms of error rate and speed-up.</p>
},
	doi = {10.1007/978-3-642-15364-8_43},
	url = {http://dx.doi.org/10.1007/978-3-642-15364-8_43},
	author = {Tuvshintur Tserendorj and Stephan Grimm and Pascal Hitzler},
	editor = {Pablo Garcia Bringas and Abdelkader Hameurlain and Gerald Quirchmayr}
}
@conference {117,
	title = {A Preferential Tableaux Calculus for Circumscriptive ALCO},
	booktitle = {Web Reasoning and Rule Systems, Third International Conference, RR 2009},
	volume = {5837},
	year = {2009},
	pages = {40{\textendash}54},
	publisher = {Springer},
	organization = {Springer},
	address = {Chantilly, VA, USA},
	abstract = {<p class="rtejustify">Nonmonotonic extensions of description logics (DLs) allow for default and local closed-world reasoning and are an acknowledged desired feature for applications, e.g. in the Semantic Web. A recent approach to such an extension is based on McCarthy{\textquoteright}s circumscription, which rests on the principle of minimising the extension of selected predicates to close off dedicated parts of a domain model. While decidability and complexity results have been established in the literature, no practical algorithmisation for circumscriptive DLs has been proposed so far. In this paper, we present a tableaux calculus that can be used as a decision procedure for concept satisfiability with respect to conceptcircumscribed ALCO knowledge bases. The calculus builds on existing tableaux for classical DLs, extended by the notion of a preference clash to detect the non-minimality of constructed models.</p>
},
	doi = {10.1007/978-3-642-05082-4_4},
	url = {http://dx.doi.org/10.1007/978-3-642-05082-4_4},
	author = {Stephan Grimm and Pascal Hitzler},
	editor = {Axel Polleres and Terrance Swift}
}
@proceedings {315,
	title = {Proceedings of the Fourth International Workshop on Applications of Semantic Technologies, AST2009, at Informatik2009, L{\"u}beck, Germany, October 2009},
	journal = {INFORMATIK 2009 - Im Fokus das Leben},
	year = {2009},
	pages = {381-400},
	publisher = {Bonner K{\"o}llen Verlag},
	address = {L{\"u}beck, Germany},
	issn = {978-3-88579-248-2},
	editor = {Stephan Grimm and Pascal Hitzler}
}
