Many tasks require correct and meaningful communication and integration among intelligent agents and information resources. A major barrier to such interoperability is semantic heterogeneity: different applications, databases, and agents may ascribe disparate meanings to the same terms or use distinct terms to convey the same meaning. Even when software applications use the same terminology, they often associate different semantics with the terms. This clash over the meaning of the terms prevents the seamless exchange of information among the applications. The development and application of ontologies play a central role in achieving semantic integration. An ontology is a computer-interpretable specification that is used by an agent, application, or other information resource to declare what terms it uses, and what the terms mean. Ontologies support the semantic integration of software systems through a shared understanding of the terminology in their respective ontologies.
One obstacle to the development of expressive formal ontologies for various domains has been the lack of an adequate set of generic ontologies that can be used to specify the semantics of primitive concepts. For example, any product ontology must refer to relationships from geometry and topology, and different manufacturing standards may require different ontologies for time. It will therefore be necessary to first identify existing ontologies within the research community that will be able to provide these foundations for manufacturing ontologies, and then to integrate these ontologies with the semantics for the terminology of the manufacturing standards.
The objective of the COLORE project is to construct an open repository of first-order ontologies that will serve as a testbed for ontology evaluation and integration techniques, and that can support the design, evaluation, and application of ontologies in first-order logic. All ontologies are specified using Common Logic (ISO 24707), which is a recently standardized logical language for the specification of first-order ontologies and knowledge bases.
An additional application of this work will be the development of new manufacturing ontologies. Several standards exist which support interoperability among manufacturing software systems; of particular interest are ISO 10303 STEP (Standard for the Exchange of Product data), ISO 14694 (NC Data), ISO 15531 MANDATE (Manufacturing Data Exchange), ISO 5608 (Cutting Tools), ISO 1832 (Cutting Tool Inserts), ISO 16100 (Manufacturing Software Capability), ENV 12204 (Constructs for Enterprise Modelling), and ENV 40003 (Framework for Enterprise Modelling). There are also several emerging standards in the area of business-to-business (B2B) electronic commerce being proposed by organizations such as Open Applications Group, Object Management Group, and RosettaNet; these standards include Semantic Vocabulary for Business Rules (SVBR), Business Process Modelling Language (BPMN), and SysML.
Nevertheless, these standards have many overlapping concepts, and each standard often has a different intended semantics for these concepts. This clash of semantics arises from the lack of a explicit formal axiomatization of the terminology within an ontology. Furthermore, the formalisms currently being used to represent manufacturing concepts are weak; consequently, the standards are difficult to verify by customers, complex to maintain, and costly to harmonize.
By providing ontologies for the above standards, we can enable the integration of manufacturing software applications in domains that require the use of multiple standards. Ideally, ontologies for supply chain management and enterprise integration can be incorporated into manufacturing standards thus avoiding the barriers to interoperability that could result from a lack of harmonization.