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Module Extraction via Query Inseparability in OWL 2 QL

Boris Konev, Roman Kontchakov, Michel Ludwig, Thomas Schneider, Frank Wolter, Michael Zakharyaschev
2011 International Workshop on Description Logics  
We show that deciding conjunctive query inseparability for OWL 2 QL ontologies is PSpace-hard and in ExpTime.  ...  We give polynomial-time (incomplete) algorithms and demonstrate by experiments that they can be used for practical module extraction.  ...  For comparison, we extracted modules from OWL 2 QL approximations of the well-known IMDB and LUBM ontologies.  ... 
dblp:conf/dlog/KonevKLSWZ11 fatcat:nb27iiwmsvdu7aggmc2ah4mrny

Conjunctive Query Inseparability in OWL 2 QL is ExpTime-hard

Roman Kontchakov, Vladislav Ryzhikov, Michael Zakharyaschev
2013 International Workshop on Description Logics  
Here we show that the problem is ExpTime-complete and, in fact, deciding whether two OWL 2 QL knowledge bases (each with its own data) give the same answers to any conjunctive query is ExpTime-hard.  ...  We settle an open question on the complexity of the following problem: given two OWL 2 QL TBoxes and a signature, decide whether these TBoxes return the same answers to any conjunctive query over any data  ...  Conclusion In this paper, we have proved that the Σ-query entailment and inseparability problems for both OWL 2 QL KBs and TBoxes are ExpTime-hard.  ... 
dblp:conf/dlog/KontchakovRZ13 fatcat:lehpynjm4remdfh3fcxqwibfpq

Formal Properties of Modularisation [chapter]

Boris Konev, Carsten Lutz, Dirk Walther, Frank Wolter
2009 Lecture Notes in Computer Science  
Modularity of ontologies is currently an active research field, and many different notions of a module have been proposed.  ...  We explore these properties in detail in the contexts of description logic and classical predicate logic and put them into the perspective of well-known concepts from logic and modular software specification  ...  The pair (QL, S) serves as an interface so that groups of independent modules can interact by querying each other via this interface.  ... 
doi:10.1007/978-3-642-01907-4_3 fatcat:hrgyp2zzz5hajcg6ttvkt2vati

Query Inseparability by Games

Elena Botoeva, Roman Kontchakov, Vladislav Ryzhikov, Frank Wolter, Michael Zakharyaschev
2014 International Workshop on Description Logics  
We also employ our results to resolve two major open problems for OWL 2 QL by showing that TBox query inseparability and the membership problem for universal UCQ-solutions in knowledge exchange are both  ...  We investigate conjunctive query inseparability of description logic knowledge bases (KBs) with respect to a given signature, a fundamental problem for KB versioning, module extraction, forgetting and  ...  the W3C profiles OWL 2 QL and OWL 2 EL.  ... 
dblp:conf/dlog/BotoevaKRWZ14 fatcat:pdxwpzpte5ej5czrrludzfe5lu

Logic-based ontology comparison and module extraction, with an application to DL-Lite

Roman Kontchakov, Frank Wolter, Michael Zakharyaschev
2010 Artificial Intelligence  
Inseparability relations between ontologies are then used to develop a formal framework for (minimal) module extraction.  ...  syntactic locality-based module extraction algorithm with our non-tractable extraction algorithms and using the multi-engine QBF solver aqme.  ...  Acknowledgements We thank Marco Benedetti, Florian Lonsing, Luca Pulina, Uli Sattler, Thomas Schneider and Petra Selmer for their help in conducting experiments described in Section 9.  ... 
doi:10.1016/j.artint.2010.06.003 fatcat:vabfbrgqgrdkzo5ouz7l3qaqzu

Ontologies and Data Management: A Brief Survey

Thomas Schneider, Mantas Šimkus
2020 Künstliche Intelligenz  
In order to align and complete data, systems may rely on taxonomies and background knowledge that are provided in the form of an ontology.  ...  Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long  ...  OWL 2 QL is based on the DL-Lite family of DLs and enables very efficient sound and complete query answering using standard relational database technology [14] .  ... 
doi:10.1007/s13218-020-00686-3 pmid:32999532 pmcid:PMC7497697 fatcat:zeskjfjrpvcojjh6q3yjzhlyci

Games for query inseparability of description logic knowledge bases

Elena Botoeva, Roman Kontchakov, Vladislav Ryzhikov, Frank Wolter, Michael Zakharyaschev
2016 Artificial Intelligence  
logics underpinning OWL 2 QL and OWL 2 EL.  ...  We use these results to resolve two major open problems for OWL 2 QL by showing that TBox query inseparability and the membership problem for universal conjunctive query solutions in knowledge exchange  ...  21] and ELH dr ⊥ [22] underlying the OWL 2 profiles OWL 2 QL and OWL 2 EL (www.w3.org/TR/owl2-profiles).  ... 
doi:10.1016/j.artint.2016.01.010 fatcat:hzpcvty7wza53a3lokdb54malm

The Distributed Ontology, Modeling and Specification Language – DOL [chapter]

Till Mossakowski, Mihai Codescu, Fabian Neuhaus, Oliver Kutz
2015 Studies in Universal Logic  
There is a diversity of ontology languages in use, among them OWL, RDF, OBO, Common Logic, and F-logic.  ...  There is ontology matching and alignment, module extraction, interpolation, ontologies linked by bridges, interpretation and refinement, and combination of ontologies, models and specifications.  ...  We also want to thank Yazmin Angelica Ibañez, Thomas Schneider and Carsten Lutz for valuable input on interpolation and module extraction.  ... 
doi:10.1007/978-3-319-15368-1_21 fatcat:vuhl4ynknzbfhi5s6mxgnw7ihy

The Logical Difference for the Lightweight Description Logic EL

B. Konev, M. Ludwig, D. Walther, F. Wolter
2012 The Journal of Artificial Intelligence Research  
We investigate this approach for terminologies given in the description logic EL extended with role inclusions and domain and range restrictions for three distinct types of queries: subsumption, instance  ...  In all three cases, we present polynomial-time algorithms that decide whether two terminologies give the same answers to queries over a given vocabulary and compute a succinct representation of the difference  ...  CEX2 to the extracted Σ-modules.  ... 
doi:10.1613/jair.3552 fatcat:5akbbxytonhkhpl6gcm4lnnjpi

Organizing institutions

2015 2015 21st International Conference on Automation and Computing (ICAC)  
Ontop has two tools: OntopPro, which is a Protege 4 plugin that implements a graphic mapping editor; and Quest, which is a SPARQL query engine/reasoner that supports RDFS and OWL 2 QL entailment regimes  ...  The system overall architecture is shown in Figure 2 . It consists of four basic modules: User Interface Layer, Query Reformulation, Mapping Component and Data Access Layer. 1.  ...  Sofia Pinto 2 , Sheila Reinehr 1 , Andreia Malucelli 1 Abstract. The ontology development area has received some attention over the years.  ... 
doi:10.1109/iconac.2015.7313649 fatcat:prpaqk2d4bhnlom25xxztiimaq

Organizing institutions

2016 2016 10th International Conference on Software, Knowledge, Information Management & Applications (SKIMA)  
Ontop has two tools: OntopPro, which is a Protege 4 plugin that implements a graphic mapping editor; and Quest, which is a SPARQL query engine/reasoner that supports RDFS and OWL 2 QL entailment regimes  ...  The system overall architecture is shown in Figure 2 . It consists of four basic modules: User Interface Layer, Query Reformulation, Mapping Component and Data Access Layer. 1.  ...  Sofia Pinto 2 , Sheila Reinehr 1 , Andreia Malucelli 1 Abstract. The ontology development area has received some attention over the years.  ... 
doi:10.1109/skima.2016.7916183 fatcat:ctichxcphnhj7ci3h4lu662gbi

Knowledge base exchange: The case of OWL 2 QL

Marcelo Arenas, Elena Botoeva, Diego Calvanese, Vladislav Ryzhikov
2016 Artificial Intelligence  
For this purpose, we focus on the Description Logic underlying OWL 2 QL, which is the profile [27] of the standard Web Ontology Language OWL 2 [28] that has been specifically designed for efficient query  ...  In particular, we consider DL-Lite R , which is the logic underlying the OWL 2 QL profile of OWL 2. In this framework, we are interested in three types of solutions: universal solutions, 3  ...  Then, K 1 Σquery entails K 2 if for each UCQ q over Σ, cert(q, K 2 ) ⊆ cert(q, K 1 ). Moreover, K 1 and K 2 are Σ-query inseparable, if they Σ-query entail each other.  ... 
doi:10.1016/j.artint.2016.05.002 fatcat:kq37x7itcbfz3mahokv2qtthi4

The Concept Difference for EL-Terminologies using Hypergraphs

Andreas Ecke, Michel Ludwig, Dirk Walther
2013 ACM Symposium on Document Engineering  
Numerous ontologies have been developed so far, especially in knowledge intensive areas such as the biomedical domain.  ...  In this paper we investigate the logical difference problem using a hypergraph representation of EL-terminologies. We focus solely on the concept difference wrt. a signature.  ...  The relation →T is a special reachability notion in G Σ T that mimics reasoning wrt. T . The definition of →T is related to the completion algorithm for classification in EL [1] and OWL 2 QL [8] .  ... 
dblp:conf/doceng/EckeL013 fatcat:ujqemkbtardbdjcqhruvs2axb4

Computing Repairs of Inconsistent DL-Programs over EL Ontologies

Thomas Eiter, Michael Fink, Daria Stepanova
2016 The Journal of Artificial Intelligence Research  
However, the algorithm exploits particular features of DL-Lite A and can not be readily applied to repairing DL-programs over other prominent DLs like EL. compared to DL-Lite A , in EL support sets may  ...  The latter are constructed using datalog query rewriting techniques as well as ontology approximation based on logical difference between EL-terminologies.  ...  The latter have been widely studied for extracting modules of ontologies (Nortje et al., 2013) , determining concept difference between EL terminologies (Ecke et al., 2013) , efficient reasoning in OWL  ... 
doi:10.1613/jair.5047 fatcat:zufhilynxjervm3lipreu5m554

Description Logic Knowledge Base Exchange [chapter]

Elena Botoeva
2012 Lecture Notes in Computer Science  
Let K be an OWL 2 QL KB.  ...  Most of the result in this thesis are for DL-Lite R , a prominent member of the DL-Lite family, the logic underlying OWL 2 QL, one of the profiles of OWL 2.  ...  Let A 1 be an ABox over Σ 1 such that T 1 , A 1 is consistent, denote by K 1 the KB T 1 ∪ T 12 , A 1 , and by K 2 the KB T 2 ∪ T 12 , A 1 . We show K 1 is Σ 2 -query equivalent to K 2 .  ... 
doi:10.1007/978-3-642-33203-6_30 fatcat:vcs2m4p6rjadpcuj63hwacwocq
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