Modularity and web ontologies (original) (raw)

Just the right amount: extracting modules from ontologies

2007

Abstract The ability to extract meaningful fragments from an ontology is key for ontology re-use. We propose a definition of a module that guarantees to completely capture the meaning of a given set of terms, ie, to include all axioms relevant to the meaning of these terms, and study the problem of extracting minimal modules. We show that the problem of determining whether a subset of an ontology is a module for a given vocabulary is undecidable even for rather restricted sub-languages of OWL DL.

Extracting Modules from Ontologies: Theory and Practice (Technical Report)

Abstract The ability to extract meaningful fragments from an ontology is essential for ontology re-use. We propose a definition of a module that guarantees to completely capture the meaning of a given set of terms, ie, to include all axioms relevant to the meaning of these terms, and study the problem of extracting minimally sized modules. We show that the problem of determining whether a subset of an ontology is a module for a given vocabulary is undecidable even for rather restricted sub-languages of OWL DL.

DeMoSt: a Tool for Exploring the Decomposition and the Modular Structure of OWL Ontologies

2011

Motivation In relevant application fields ontologies are often maintained as huge monolithic collections of axioms in single files, as for some ontologies in the NCBO BioPortal repository 4 , like the Gene Ontology (∼ 60, 000 axioms). Such representation is not ideal for applications which only require access limited to individual fragments of the ontology. As an example, the reasoning service provided needs just a small part of it to be performed, and loading only the necessary bit to the task can reduce substantially time and memory required, improving the performance of the system. Hence it is important to investigate the possibility of maintaining ontologies in a more flexible form.

Extracting modules from ontologies: A logic-based approach

2009

The ability to extract meaningful fragments from an ontology is essential for ontology reuse. We propose a definition of a module that guarantees to completely capture the meaning of a given set of terms, ie, to include all axioms relevant to the meaning of these terms. We show that the problem of determining whether a subset of an ontology is a module for a given vocabulary is undecidable even for OWL DL. Given these negative results, we propose sufficient conditions for a for a fragment of an ontology to be a module.

Extracting modules from ontologies: Theory and practice

2007

The ability to extract meaningful fragments from an ontology is essential for ontology re-use. We propose a definition of a module that guarantees to completely capture the meaning of a given set of terms, i.e., to include all axioms relevant to the meaning of these terms, and study the problem of extracting minimally sized modules. We show that the problem of determining whether a subset of an ontology is a module for a given vocabulary is undecidable even for rather restricted sub-languages of OWL DL. Hence we propose two "approximations", i.e., alternative definitions of modules for a vocabulary that still provide the above guarantee, but that are possibly too strict, and that may thus result in larger modules: the first approximation is semantic and can be checked using existing DL reasoners; the second is syntactic, and can be computed in polynomial time. Finally, we report on an empirical evaluation of our syntactic approximation that demonstrates that the modules we extract are surprisingly small.

A Semantic-based Approach for Ontology Module Extraction

Proceedings of the International Conference on Knowledge Engineering and Ontology Development, 2013

Ontology modularization is crucial to support knowledge reuse on the ever increasing Semantic Web. However, modularization methods that serve the reuse goal are often intended for humans to assist them in building new ontologies, rather than for applications that need only a relevant part of an existing ontology. Moreover, modules obtained are always subject to verification and maintenance by humans to validate the semantic consistency of their contents. In this paper, we investigate how semantic comparisons may provide a module relevant to a set of terms which are not part of the ontology. Our objective is to extract a module which may be usable as a separate ontology. The user does not need to be familiar with the exact terms used inside the ontology beforehand to extract from it a module for a specific application/knowledge sub domain.

Characterizing Modular Ontologies

2012

Since large monolithic ontologies are difficult to handle and reuse, ontology modularization has attracted increasing attention. Several approaches and tools have been developed to support ontology modularization. Despite these efforts, a lack of knowledge about characteristics of modularly organized ontologies prevents further development. This work aims at characterizing modular ontologies. Therefore, we analyze existing modular ontologies by applying selected metrics from software engineering in order to identify recurring structures, i.e. patterns in modularly organized ontologies. The contribution is a set of four patterns which characterize modularly organized ontologies.