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Model-based Revision Operators for Terminologies in Description Logics
"... The problem of revising an ontology consistently is closely related to the problem of belief revision which has been widely discussed in the literature. Some syntax-based belief revision operators have been adapted to revise ontologies in Description Logics (DLs). However, these operators remove the ..."
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Cited by 33 (5 self)
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The problem of revising an ontology consistently is closely related to the problem of belief revision which has been widely discussed in the literature. Some syntax-based belief revision operators have been adapted to revise ontologies in Description Logics (DLs). However, these operators remove the whole axioms to resolve logical contradictions and thus are not fine-grained. In this paper, we propose three model-based revision operators to revise terminologies in DLs. We show that one of them is more rational than others by comparing their logical properties. Therefore, we focus on this revision operator. We also consider the problem of computing the result of revision by our operator with the help of the notion of concept forgetting. Finally, we analyze the computational complexity of our revision operator. 1
Decomposing description logic ontologies
, 2010
"... Recent years have seen the advent of large and complex ontologies, most notably in the medical domain. As a consequence, structuring mechanisms for ontologies are nowadays viewed as an indispensible tool. A basic such mechanism is the automatic decomposition of the vocabulary of an ontology into ind ..."
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Cited by 17 (1 self)
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Recent years have seen the advent of large and complex ontologies, most notably in the medical domain. As a consequence, structuring mechanisms for ontologies are nowadays viewed as an indispensible tool. A basic such mechanism is the automatic decomposition of the vocabulary of an ontology into independent parts. In this paper, we study decompositions that are syntax independent in the sense that the resulting partitioning depends only on the meaning of the vocabulary items, but not on the concrete syntactic form of the axioms in the ontology. We present the first systematic investigation of decompositions of this type in the context of ontologies. Specifically, we focus on ontologies formulated in description logics and provide a variety of results that range from theorems stating the existence of unique finest decompositions to complexity results and algorithms computing decompositions. We also investigate the relationship between the existence of unique finite decompositions and a variant of the Craig interpolation property called parallel interpolation.
Query and Predicate Emptiness in Description Logics
, 2010
"... Ontologies can be used to provide an enriched vocabulary for the formulation of queries over instance data. We identify query emptiness and predicate emptiness as two central reasoning services in this context. Query emptiness asks whether a given query has an empty answer over all data sets formula ..."
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Cited by 13 (6 self)
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Ontologies can be used to provide an enriched vocabulary for the formulation of queries over instance data. We identify query emptiness and predicate emptiness as two central reasoning services in this context. Query emptiness asks whether a given query has an empty answer over all data sets formulated in a given signature. Predicate emptiness is defined analogously, but quantifies universally over all queries that contain a given predicate. In this paper, we determine the computational complexity of query emptiness and predicate emptiness in the EL, DL-Lite, and ALC-families of description logics, investigate the connection to ontology modules, and perform a practical case study to evaluate the new reasoning services.
F.: The logical difference for the lightweight description logic EL
- Journal of Artificial Intelligence Reserach (JAIR
, 2012
"... We study a logic-based approach to versioning of ontologies. Under this view, ontologies provide answers to queries about some vocabulary of interest. The difference between two versions of an ontology is given by the set of queries that receive different answers. We investigate this approach for te ..."
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Cited by 12 (7 self)
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We study a logic-based approach to versioning of ontologies. Under this view, ontologies provide answers to queries about some vocabulary of interest. The difference between two versions of an ontology is given by the set of queries that receive different answers. 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, and conjunctive queries. In all three cases, we present polynomialtime algorithms that decide whether two terminologies give the same answers to queries over a given vocabulary and compute a succinct representation of the difference if it is nonempty. We present an implementation, CEX2, of the developed algorithms for subsumption and instance queries and apply it to distinct versions of Snomed CT and the NCI ontology. 1.
Beth Definability in Expressive Description Logics
- PROCEEDINGS OF THE TWENTY-SECOND INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE
, 2011
"... The Beth definability property, a well-known property from classical logic, is investigated in the context of description logics (DLs): if a general L-TBox implicitly defines an L-concept in terms of a given signature, where L is a DL, then does there always exist over this signature an explicit def ..."
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Cited by 2 (1 self)
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The Beth definability property, a well-known property from classical logic, is investigated in the context of description logics (DLs): if a general L-TBox implicitly defines an L-concept in terms of a given signature, where L is a DL, then does there always exist over this signature an explicit definition in L for the concept? This property has been studied before and used to optimize reasoning in DLs. In this paper a complete classification of Beth definability is provided for extensions of the basic DL ALC with transitive roles, inverse roles, role hierarchies, and/or functionality restrictions, both on arbitrary and on finite structures. Moreover, we present a tableau-based algorithm which computes explicit definitions of at most double exponential size. This algorithm is optimal because it is also shown that the smallest explicit definition of an implicitly defined concept may be double exponentially long in the size of the input TBox. Finally, if explicit definitions are allowed to be expressed in first-order logic then we show how to compute them in EXPTIME.
Semantics of the Distributed Ontology Language: Institutes and Institutions
"... The Distributed Ontology Language (DOL) is a recent development within the ISO standardisation initiative 17347 Ontology Integration and Interoperability (OntoIOp). In DOL, heterogeneous and distributed ontologies can be expressed, i.e. ontologies that are made up of parts written in ontology lang ..."
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Cited by 2 (2 self)
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The Distributed Ontology Language (DOL) is a recent development within the ISO standardisation initiative 17347 Ontology Integration and Interoperability (OntoIOp). In DOL, heterogeneous and distributed ontologies can be expressed, i.e. ontologies that are made up of parts written in ontology languages based on various logics. In order to make the DOL meta-language and its semantics more easily accessible to the wider ontology community, we have developed a notion of institute which are like institutions but with signature partial orders and based on standard set-theoretic semantics rather than category theory. We give an institute-based semantics for the kernel of DOL and show that this is compatible with institutional semantics. Moreover, as it turns out, beyond their greater simplicity, institutes have some further surprising advantages over institutions.
Module Extraction for Acyclic Ontologies
"... Abstract. We present an implementation (AMEX) of a module extraction algorithm for acyclic description logic ontologies. The implementation uses a QBF solver (sKizzo) to check whether one ontology is a conservative extension of another ontology relativised to interpretations of cardinality one. We e ..."
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Cited by 1 (1 self)
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Abstract. We present an implementation (AMEX) of a module extraction algorithm for acyclic description logic ontologies. The implementation uses a QBF solver (sKizzo) to check whether one ontology is a conservative extension of another ontology relativised to interpretations of cardinality one. We evaluate AMEX by applying it to NCI (the National Cancer Institute Thesaurus) and by comparing the extracted AMEX-modules with locality-based modules. We also present experiments for a hybrid approach in which AMEX and locality-based module extraction are applied iteratively to NCI. 1
Towards a Functional Approach to Modular Ontologies using Institutions
"... We propose a functional view of ontologies that emphasises their role in determining answers to queries, irrespective of the formalism in which they are written. A notion of framework is introduced that captures the situation of a global language into which both an ontology language and a query lang ..."
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We propose a functional view of ontologies that emphasises their role in determining answers to queries, irrespective of the formalism in which they are written. A notion of framework is introduced that captures the situation of a global language into which both an ontology language and a query language can be translated, in an abstract way. We then generalise existing notions of robustness from the literature, and relate these to interpolation properties that support modularisation of ontologies.
A Semantic Algebra for Modularized Description Logics Knowledge Bases
"... Subsequent years bring increasing attention into the area of modularization of Description Logics (DL) knowledge bases. The main motivation is the hope to reach the maturity of the collaborative ontology development and reuse process comparable to the one achieved by software engineering methods in ..."
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Subsequent years bring increasing attention into the area of modularization of Description Logics (DL) knowledge bases. The main motivation is the hope to reach the maturity of the collaborative ontology development and reuse process comparable to the one achieved by software engineering methods in the case of
Preservation of Modules
"... Abstract. Within the Common Logic Ontology Repository (COLORE), relation-ships among ontologies such as the notions of faithful interpretability, logical syn-onymy, and reducibility have been used for ontology verification. Earlier work has shown how to use these relationships to find modules of the ..."
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Abstract. Within the Common Logic Ontology Repository (COLORE), relation-ships among ontologies such as the notions of faithful interpretability, logical syn-onymy, and reducibility have been used for ontology verification. Earlier work has shown how to use these relationships to find modules of theories, so a natural ques-tion is to determine how we can use the decomposition of one theory into modules to find the modules of another theory in the repository. In this paper, we examine a number of ontologies for which faithful interpretability and logical synonymy do not preserve their modules. Nevertheless, we identify a class of interpretations among theories which guarantees that the modules of a theory are preserved. We also show that the modules of reducible theories are preserved by logical synonymy.
