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| 2. |
- Dragisic, Zlatan
(författare)
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Completing the Is-a Structure in Description Logics Ontologies
- 2014
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The World Wide Web contains large amounts of data and in most cases this data is without any explicit structure. The lack of structure makes it difficult for automated agents to understand and use such data. A step towards a more structured World Wide Web is the idea of the Semantic Web which aims at introducing semantics to data on the World Wide Web. One of the key technologies in this endeavour are ontologies which provide means for modeling a domain of interest.Developing and maintaining ontologies is not an easy task and it is often the case that defects are introduced into ontologies. This can be a problem for semantically-enabled applications such as ontology-based querying. Defects in ontologies directly influence the quality of the results of such applications as correct results can be missed and wrong results can be returned.This thesis considers one type of defects in ontologies, namely the problem of completing the is-a structure in ontologies represented in description logics. We focus on two variants of description logics, the EL family and ALC, which are often used in practice.The contributions of this thesis are as follows. First, we formalize the problem of completing the is-a structure as a generalized TBox abduction problem (GTAP) which is a new type of abduction problem in description logics. Next, we provide algorithms for solving GTAP in the EL family and ALC description logics. Finally, we describe two implemented systems based on the introduced algorithms. The systems were evaluated in two experiments which have shown the usefulness of our approach. For example, in one experiment using ontologies from the Ontology Alignment Evaluation Initiative 58 and 94 detected missing is-a relations were repaired by adding 54 and 101 is-a relations, respectively, introducing new knowledge to the ontologies.
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| 3. |
- Dragisic, Zlatan, et al.
(författare)
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Completing the is-a structure of biomedical ontologies
- 2014
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Ingår i: Data Integration in the Life Sciences 10th International Conference, DILS 2014, Lisbon, Portugal, July 17-18, 2014. Proceedings. - Berlin : Springer Science+Business Media B.V.. - 9783319085890 - 9783319085906 ; , s. 66-80
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Konferensbidrag (refereegranskat)abstract
- Ontologies in the biomedical domain are becoming a key element for data integration and search. The usefulness of the applications which use ontologies is often directly influenced by the quality of ontologies, as incorrect or incomplete ontologies might lead to wrong or incomplete results for the applications. Therefore, there is an increasing need for repairing defects in ontologies. In this paper we focus on completing ontologies. We provide an algorithm for completing the is-a structure in TeX ontologies which covers many biomedical ontologies. Further, we present an implemented system based on the algorithm as well as an evaluation using three biomedical ontologies.
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| 4. |
- Dragisic, Zlatan, et al.
(författare)
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Results of the Ontology Alignment Evaluation Initiative 2014
- 2014
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Ingår i: International Workshop on Ontology Matching. ; , s. 61-104
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Konferensbidrag (refereegranskat)abstract
- Ontology matching consists of finding correspondences between se-mantically related entities of two ontologies. OAEI campaigns aim at comparingontology matching systems on precisely defined test cases. These test cases canuse ontologies of different nature (from simple thesauri to expressive OWL on-tologies) and use different modalities, e.g., blind evaluation, open evaluation andconsensus. OAEI 2014 offered 7 tracks with 9 test cases followed by 14 partici-pants. Since 2010, the campaign has been using a new evaluation modality which provides more automation to the evaluation. This paper is an overall presentationof the OAEI 2014 campaign.
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| 5. |
- Wei-Kleiner, Fang, et al.
(författare)
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Abduction Framework for Repairing Incomplete EL Ontologies: Complexity Results and Algorithms
- 2014
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Ingår i: Proceedings of the 28th AAAI Conference on Artificial Intelligence. - Palo Alto, CA, USA : AAAI Press. - 9781577356783 ; , s. 1120-1127
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Konferensbidrag (refereegranskat)abstract
- In this paper we consider the problem of repairing missing is-a relations in ontologies.We formalize the problem as a generalized TBox abduction problem (GTAP). Based on this abduction framework, we present complexity results for the existence, relevance and necessity decision problems for the GTAP with and without some specific preference relations for ontologies that can be represented using a member of the EL family of description logics. Further, we present algorithms for finding solutions, a system as well as experiments.
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