I am grateful to the conference organizers from UNESCO and ICSU for the opportunity to present this talk and to Dr. Nicole Biros for her role as organizer of this session. Dr. Jorge Allende, our chairman, has been a colleague since our student days. He is a distinguished biochemist and citizen of Chile and it is an honor to share this occasion with him. Now, as we look to a new century and mill...

Horn description logics (Horn-DLs) have recently started to attract attention due to the fact that their (worst-case) data complexities are in general lower than their overall (i.e. combined) complexities, which makes them attractive for reasoning with large ABoxes. However, the natural question whether Horn-DLs also provide advantages for TBox reasoning has hardly been addressed so far. In thi...

Description Logics (DLs) are the formalism underlying the standard web ontology language OWL 2. DLs have formal semantics which are the basis for powerful reasoning services. In this paper, we introduce the basic notions of DLs and the techniques that realize subsumption—the fundamental reasoning service of DL systems. We discuss two reasoning methods for this service: the tableau method for ex...

An endogenous digitalis-like substance (DLS) may be involved in the pathogenesis of essential hypertension and pre-eclampsia. The digoxin levels in maternal and cord blood of 504 randomly selected patients were determined. Since none of the patients received digoxin, these levels indicated a crossreacting substance (immunoreactive DLS). DLS levels were significantly higher in the cord blood of ...

Horn description logics (Horn-DLs) have recently started to attract attention due to the fact that their (worst-case) data complexities are in general lower than their overall (i.e. combined) complexities, which makes them attractive for reasoning with large ABoxes. However, the natural question whether Horn-DLs also provide advantages for TBox reasoning has hardly been addressed so far. In thi...

Classical Description Logics (DLs) are not suitable to represent vague pieces of information. The attempts to achieve a solution have lead to the birth of fuzzy DLs and rough DLs. In this work, we provide a simple solution to join these two formalisms and define a fuzzy rough DL. We also show how to extend two reasoning algorithms for fuzzy DLs, which are implemented in the fuzzy DL reasoners f...

Recently, the problem of representing uncertainty in Description Logics (DLs) has received an increasing attention. In probabilistic DLs, axioms contain numeric parameters that are often difficult to specify or to tune for a human. In this paper we present an approach for learning and tuning the parameters of probabilistic ontologies from data. The resulting algorithm, called EDGE, is targeted ...