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Least Common Subsumers and Most Specific Concepts in a Description Logic with Existential Restrictions and Terminological Cycles

Franz Baader
2003 International Joint Conference on Artificial Intelligence  
In description logics with existential restrictions, the most specific concept need not exist if one restricts the attention to concept descriptions or acyclic TBoxes.  ...  Computing least common subsumers (Ics) and most specific concepts (msc) are inference tasks that can support the bottom-up construction of knowledge bases in description logics.  ...  in description logics with existential restrictions was largely unexplored.  ... 
dblp:conf/ijcai/Baader03 fatcat:dzpettnykfcgriw7qd3x7u4xyi

Speeding up Approximation with Nicer Concepts

Anni-Yasmin Turhan, Yusri Bong
2007 International Workshop on Description Logics  
Concept approximation is an inference service for Description Logics that provides "translations" of concept descriptions from one DL to a less expressive DL.  ...  In this paper we provide relaxed conditions for this class of ALC-concept descriptions, extend this notion to number restrictions and report on a first implementation of this method for ALCN -ALEN -approximation  ...  Motivation Approximation is a non-standard inference service in Description Logics (DLs) introduced in [3] .  ... 
dblp:conf/dlog/TurhanB07 fatcat:wkoyeefu6betdlav443ri22mqm

Sonic: System Description

Anni-Yasmin Turhan, Christian Kissig
2004 International Workshop on Description Logics  
Description Logics with number restrictions.  ...  In addition to that our implementation extends an earlier implementation of the least common subsumer and of the approximation inference service to more expressive Description Logics, more precisely to  ...  Firstly, the number restrictions for roles, more precisely the at most restrictions, necessitates merging of role-successors mentioned in the existential restrictions.  ... 
dblp:conf/dlog/TurhanK04 fatcat:la2gbmnvencwfoj2itof7wn464

Computing Least Common Subsumers in Description Logics with Existential Restrictions

Franz Baader, Ralf Küsters, Ralf Molitor
1999 International Joint Conference on Artificial Intelligence  
The main new contribution of this paper is the treatment of description logics with existential restrictions.  ...  Previous work on how to compute the lcs has concentrated on description logics that allow for universal value restrictions, but not for existential restrictions.  ...  In the description logic concept, descriptions are formed using the constructors top-concept , conjunction. and existential restriction .  ... 
dblp:conf/ijcai/BaaderKM99 fatcat:rki7bejk2vdy5hqmqukespsqsa

Measuring Similarity in Description Logics Using Refinement Operators [chapter]

Antonio A. Sánchez-Ruiz, Santiago Ontañón, Pedro Antonio González-Calero, Enric Plaza
2011 Lecture Notes in Computer Science  
Specifically, similarity of two individuals is assessed by first computing their most specific concepts, then the least common subsumer of these two concepts, and finally measuring their distances in the  ...  This paper presents a novel measure for assessing similarity between individuals represented using Description Logic (DL).  ...  REM = REM ∪ρ(E) 9: else 10: if D ∈ DS : E D Finally, ρ 4 refines a concept C adding the most general existential restrictions which neither subsume nor are subsumed by other existential restrictions currently  ... 
doi:10.1007/978-3-642-23291-6_22 fatcat:2gtiv3djcndolegjsymyyep5wu

Efficient Approximation in DL-Lite of OWL 2 Ontologies

Marco Console, Valerio Santarelli, Domenico Fabio Savo
2013 International Workshop on Description Logics  
With the aim to use an ontology as a formal description of the domain of interest, the use of expressive languages proves to be useful.  ...  In this work we present our notion of ontology approximation and present an algorithm for computing the approximation of OWL 2 ontologies by means of DL-Lite TBoxes.  ...  The concept ∃Q.C, or qualified existential restriction, denotes the qualified domain of Q with respect to C, i.e., the set of objects that Q relates to some instance of C.  ... 
dblp:conf/dlog/ConsoleSS13 fatcat:mizg75b7azbtplblbutqbd4jo4

A dissimilarity measure for ALC concept descriptions

Claudia d'Amato, Nicola Fanizzi, Floriana Esposito
2006 Proceedings of the 2006 ACM symposium on Applied computing - SAC '06  
This work presents a dissimilarity measure for an expressive Description Logic endowed with the principal constructors employed in the standard representations for ontological knowledge.  ...  In particular, the focus is on the definition of a dissimilarity measure for the ALC description logic based both on the syntax and on the semantics of the descriptions.  ...  most specific concept).  ... 
doi:10.1145/1141277.1141677 dblp:conf/sac/dAmatoFE06 fatcat:kwyw3na6ozdcxcp5i6x4o3hdrm

Reasoning by Analogy in Description Logics Through Instance-based Learning

Claudia d'Amato, Nicola Fanizzi, Floriana Esposito
2006 Semantic Web Applications and Perspectives  
The method, which exploits a semantic dissimilarity measure between concepts and instances, can be employed both to answer class membership queries and to predict new assertions that may be not logically  ...  In a preliminary experimentation, we show that the method is sound and it is actually able to induce new assertions that might be acquired in the knowledge base.  ...  ACKNOWLEDGMENTS This work was partially supported by the regional interest projects DIPIS (DIstributed Production as Innovative System) and DDTA (Distretto Digitale Tessile Abbigliamento) in the context  ... 
dblp:conf/swap/dAmatoFE06 fatcat:5uooqnhmangvtbfnofw7p4pj44

Incremental Learning of TBoxes from Interpretation Sequences with Methods of Formal Concept Analysis

Francesco Kriegel
2015 International Workshop on Description Logics  
Formal Concept Analysis and its methods for computing minimal implicational bases have been successfully applied to axiomatise minimal EL-TBoxes from models, so called bases of GCIs.  ...  E in C and modify E such that the resulting concept description is more specific than E, e.g., by adding a conjunct, or by adjusting an existential restriction. 2.  ...  The next definition extends their notion to model-based most-specific concept descriptions relative to a TBox. Definition 2 (Relative model-based most-specific concept description).  ... 
dblp:conf/dlog/Kriegel15 fatcat:jeqrgrvq6vep5fygve3gjffjdu

The Revival of Structural Subsumption in Tableau-based Reasoners

Ralf Möller, Volker Haarslev, Sebastian Wandelt
2008 International Workshop on Description Logics  
The paper summarizes our experiences with optimization techniques for well-known tableau-based description logic reasoning systems, and analyzes the performance of very simple techniques to cope with Tboxes  ...  The techniques analyzed in this paper have been tested with RacerPro, but they can be embedded into other tableau-based reasoners such as, e.g., Fact++ or Pellet in a seamless way.  ...  In this case, we also say that D subsumes C, or D is a subsumer of C. The set of parents of an atomic concept is the set of concept names which are most-specific subsumers w.r.t. a Tbox T .  ... 
dblp:conf/dlog/MollerHW08 fatcat:fixc7ip42jbvrjntntjgg4xzku

Extracting ALEQR Self-Knowledge Bases from Graphs

Francesco Kriegel
2015 International Conference on Formal Concept Analysis  
The technique is presented for the description logic ALEQR Self , which allows for conjunctions, primitive negations, existential restrictions, value restrictions, qualified number restrictions, existential  ...  The extracted knowledge base entails exactly all those statements that can be expressed in the chosen description logic and are encoded in the input graph.  ...  Then every model-based most specific concept description of I with role-depth ≤ δ is expressible in terms of M I,δ .  ... 
dblp:conf/icfca/Kriegel15 fatcat:sblgxv3khjeuhjxklerzvw3vpy

A Structural Subsumption based Similarity Measure for the Description Logic ALEH

Boontawee Suntisrivaraporn, Suwan Tongphu
2016 Proceedings of the 8th International Conference on Agents and Artificial Intelligence  
This checks, relative to the logical definitions in the ontology, whether one concept is more general/specific than another.  ...  Description Logics (DLs) are a family of logic-based knowledge representation formalisms, which can be used to develop ontologies in a formally well-founded way.  ...  D ⊑ E for every ALEH -concept description E with C ⊑ E. Intuitively, an approximation is the most specific concept in ALEH that subsumes the given ALC H concept.  ... 
doi:10.5220/0005819302040212 dblp:conf/icaart/Suntisrivaraporn16 fatcat:sn2sreirznhndaqzj24bpuc6lq

Expressive Approximations in DL-Lite Ontologies [chapter]

Elena Botoeva, Diego Calvanese, Mariano Rodriguez-Muro
2010 Lecture Notes in Computer Science  
The point of interest in DL-LiteA approximations is capturing entailments involving chains of existential role restrictions, which can play an essential role in query answering.  ...  In this work we present our approach to semantic (as opposed to syntactic) approximation of OWL 2 TBoxes by means of TBoxes in DL-LiteA.  ...  Preliminaries on Description Logics Description Logics (DLs) [3] are logics specifically designed for representing structured knowledge, and they provide the formal underpinning for the standard ontology  ... 
doi:10.1007/978-3-642-15431-7_3 fatcat:3jvgohq6dzalhknd6pj6r7pu3a

Computing the least common subsumer w.r.t. a background terminology

Franz Baader, Baris Sertkaya, Anni-Yasmin Turhan
2007 Journal of Applied Logic  
In order to allow the user to re-use concepts defined in such terminologies and still support the definition of new concepts by computing the lcs, we extend the notion of the lcs of concept descriptions  ...  Methods for computing the least common subsumer (lcs) are usually restricted to rather inexpressive DLs whereas existing knowledge bases are written in very expressive DLs.  ...  The most specific concept (msc) of an object o (the least common subsumer (lcs) of concept descriptions C 1 , . . . , C n ) is the most specific concept description C expressible in the given DL language  ... 
doi:10.1016/j.jal.2006.03.002 fatcat:m7unmigbe5b2bkwmvljpmem5s4

Tractable Feature Generation Through Description Logics with Value and Number Restrictions [chapter]

Nicola Fanizzi, Luigi Iannone, Nicola Di Mauro, Floriana Esposito
2006 Lecture Notes in Computer Science  
In the line of a feature generation paradigm based on relational concept descriptions, we extend the applicability to other languages of the Description Logics family endowed with specific language constructors  ...  that do not have a counterpart in the standard relational representations, such as clausal logics.  ...  This work could be extended towards more expressive languages endowed with union and full negation in order to support completely the semantic concept models mentioned before [6] .  ... 
doi:10.1007/11779568_68 fatcat:5nrqg7lcezdh7lyqru7fudayoe
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