期刊名称:Journal of Automation, Mobile Robotics & Intelligent Systems (JAMRIS)
印刷版ISSN:1897-8649
电子版ISSN:2080-2145
出版年度:2008
卷号:31
页码:273-318
出版社:Industrial Research Inst. for Automation and Measurements, Warsaw
摘要:In this paper, we propose a set of tasks that are relevant for the modular reuse
of ontologies. In order to formalize these tasks as reasoning problems, we
introduce the notions of conservative extension, safety and module for a very
general class of logic-based ontology languages. We investigate the general
properties of and relationships between these notions and study the
relationships between the relevant reasoning problems we have previously
identified. To study the computability of these problems, we consider, in
particular, Description Logics (DLs), which provide the formal underpinning of
the W3C Web Ontology Language (OWL), and show that all the problems we consider
are undecidable or algorithmically unsolvable for the description logic
underlying OWL DL. In order to achieve a practical solution, we identify
conditions sufficient for an ontology to reuse a set of symbols
``safely''---that is, without changing their meaning. We provide the notion of a
safety class, which characterizes any sufficient condition for safety, and
identify a family of safety classes--called locality---which enjoys a collection
of desirable properties. We use the notion of a safety class to extract modules
from ontologies, and we provide various modularization algorithms that are
appropriate to the properties of the particular safety class in use. Finally, we
show practical benefits of our safety checking and module extraction algorithms.