Towards a Reference Ontology of Functionality for Interoperable Annotation for Engineering Documents

). It enables engineers to access documents by specifying a function as a metadata query. Such function-oriented management is especially useful in the conceptual design phase to find previous design cases for the same required function and to find related patents. The semantic annotation about function is expected to solve the difficulty of current technical document management based on lexical expressions, that is, many terms (verbs) are used in documents for the same function (and vise versa) without clear semantics. The research issues for realization of functional annotation are (1) to establish