Matches in ScholarlyData for { ?s ?p ?o. }
- authorList hasLastItem item-1.
- item-1 type ListItem.
- item-1 hasContent eva-blomqvist.
- 423 creator grigoris-antoniou.
- 423 creator jeff-z-pan.
- 423 creator kewen-wang.
- 423 creator rodney-topor.
- 423 creator zhe-wang.
- 423 type InProceedings.
- 423 label "Concept and Role Forgetting in ALC Ontologies".
- 423 sameAs 423.
- 423 abstract "Forgetting is an important tool for reducing ontologies by eliminating some concepts and roles while preserving sound and complete reasoning. Attempts have previously been made to address the problem of forgetting in relatively simple description logics (DLs) such as DL-Lite and extended EL. The ontologies used in these attempts were mostly restricted to TBoxes rather than general knowledge bases (KBs). However, the issue of forgetting for general KBs in more expressive description logics, such as ALC and OWL DL, is largely unexplored. In particular, the problem of characterizing and computing forgetting for such logics is still open. In this paper, we first define semantic forgetting about concepts and roles in ALC ontologies and state several important properties of forgetting in this setting. We then define the result of forgetting for concept descriptions in ALC, state the properties of forgetting for concept descriptions, and present algorithms for computing the result of forgetting for concept descriptions. Unlike the case of DL-Lite, the result of forgetting for an ALC ontology does not exist in general, even for the special case of concept forgetting. This makes the problem of how to compute forgetting in ALC more challenging. We address this problem by defining a series of approximations to the result of forgetting for ALC ontologies and studying their properties and their application to reasoning tasks. We use the algorithms for computing forgetting for concept descriptions to compute these approximations. Our algorithms for computing approximations can be embedded into an ontology editor to enhance its ability to manage and reason in (large) ontologies.".
- 423 hasAuthorList authorList.
- 423 hasTopic Semantic_Web.
- 423 isPartOf proceedings.
- 423 title "Concept and Role Forgetting in ALC Ontologies".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasItem item-4.
- authorList hasItem item-5.
- authorList hasLastItem item-5.
- item-1 type ListItem.
- item-1 hasContent kewen-wang.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent zhe-wang.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent rodney-topor.
- item-3 next item-4.
- item-3 previous item-2.
- item-4 type ListItem.
- item-4 hasContent jeff-z-pan.
- item-4 next item-5.
- item-4 previous item-3.
- item-5 type ListItem.
- item-5 hasContent grigoris-antoniou.
- item-5 previous item-4.
- 424 creator jose-julio-alferes.
- 424 creator matthias-knorr.
- 424 creator terrance-swift.
- 424 type InProceedings.
- 424 label "Queries to Hybrid MKNF Knowledge Bases through Oracular Tabling".
- 424 sameAs 424.
- 424 abstract "An important issue for the Semantic Web is how to combine open-world ontology languages with closed-world (non-monotonic) rule paradigms. Several proposals for hybrid languages allow concepts to be simultaneously defined by an ontology and rules, where rules may refer to concepts in the ontology and the ontology may also refer to predicates defined by the rules. Hybrid MKNF knowledge bases are one such proposal, for which both a stable and a well-founded semantics have been defined. The definition of Hybrid MKNF knowledge bases is parametric on the ontology language, in the sense that non-monotonic rules can extend any decidable ontology language. In this paper we define a query-driven procedure for Hybrid MKNF knowledge bases that is sound with respect to the original stable model-based semantics, and is correct with respect to the well-founded semantics. This procedure is able to answer conjunctive queries, and is parametric on an inference engine for reasoning in the ontology language. Our procedure is based on an extension of a tabled rule evaluation to capture reasoning within an ontology by modeling it as an interaction with an external oracle and, with some assumptions on the complexity of the oracle compared to the complexity of the ontology language, maintains the data complexity of the well-founded semantics for hybrid MKNF knowledge bases.".
- 424 hasAuthorList authorList.
- 424 hasTopic Semantic_Web.
- 424 isPartOf proceedings.
- 424 title "Queries to Hybrid MKNF Knowledge Bases through Oracular Tabling".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasLastItem item-3.
- item-1 type ListItem.
- item-1 hasContent jose-julio-alferes.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent matthias-knorr.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent terrance-swift.
- item-3 previous item-2.
- 484 creator ignazio-palmisano.
- 484 creator paul-doran.
- 484 creator terry-payne.
- 484 creator valentina-tamma.
- 484 type InProceedings.
- 484 label "Task Oriented Evaluation of Module Extraction Techniques".
- 484 sameAs 484.
- 484 abstract "Ontology Modularization techniques identify coherent and often reusable regions within an ontology. The ability to identify such modules, thus potentially reducing the size or complexity of an ontology for a given task or set of concepts is increasingly important in the Semantic Web as domain ontologies increase in terms of size, complexity and expressivity. To date, many techniques have been developed, but evaluation of the results of these techniques is sketchy and somewhat ad hoc. Theoretical properties of modularization algorithms have only been studied in a small number of cases. This paper presents an empirical analysis of a number of modularization techniques, and the modules they identify over a number of diverse ontologies, by utilizing objective, task-oriented measures to evaluate the fitness of the modules for a number of statistical classification problems.".
- 484 hasAuthorList authorList.
- 484 hasTopic Semantic_Web.
- 484 isPartOf proceedings.
- 484 title "Task Oriented Evaluation of Module Extraction Techniques".
- authorList type List.
- authorList hasFirstItem item-1.
- authorList hasItem item-1.
- authorList hasItem item-2.
- authorList hasItem item-3.
- authorList hasItem item-4.
- authorList hasLastItem item-4.
- item-1 type ListItem.
- item-1 hasContent ignazio-palmisano.
- item-1 next item-2.
- item-2 type ListItem.
- item-2 hasContent valentina-tamma.
- item-2 next item-3.
- item-2 previous item-1.
- item-3 type ListItem.
- item-3 hasContent terry-payne.
- item-3 next item-4.
- item-3 previous item-2.
- item-4 type ListItem.