COMPONENT-ONTOLOGICAL REPRESENTATION OF FUNCTION FOR REASONING ABOUT DEVICES

We propose principles behind component-ontological representation of f unction. In this representation, the function of a component is expres sed in terms of its ports. The representation has many advantages: (i) The function of a component can be represented in isolation of its en vironment. Therefore, libraries of function models can be built. These models are re-usable. (ii) The function model of a complex device can be built by composing the function models of its components. This hel ps preserve the fidelity of representation. Further, this process can be automated. (iii) The representation is linear in space complexity: the function model of an atomic component is linear in the number of i ts ports, and that of a composite device is in most cases linear in th e number of its components. We propose Classes as a component-ontologi cal representation of function. We illustrate Classes by using it to m odel parts of a printer buffer, which has the complexity of a microcom puter. We also demonstrate how class models may be used for model-base d diagnosis. (C) 1998 Elsevier Science Limited. All rights reserved.