Abstract
Conceptual data modeling is essential for engineering applications. IDEF1X (Integration Definition for Information Modeling) data model provides a formal framework for consistent modeling of the data necessary for the integration of various functional areas and its basic idea has been extensively applied in current industry. Information in real-world applications is often vague or ambiguous. Fuzziness is inherent in many engineering activities. In order to completely model fuzzy engineering information at different abstraction levels of data model, object instances and attribute values in the IDEF1X data model, this paper introduces three levels of fuzziness into the IDEF1X data model, and the formal descriptions and the corresponding graphical representations are hereby presented. The formal transformation from the fuzzy IDEF1X data model to the fuzzy object-oriented database model is investigated. The formal transformation approaches proposed in the paper are demonstrated with examples.