Function in device representation

We explore the meanings of the terms 'structure', 'behaviour', and, especia lly, 'function' in engineering practice. Computers provide great assistance in calculation tasks in engineering practice, but they also have great pot ential for helping with reasoning tasks. However, realising this vision req uires precision in representing engineering knowledge, in which the terms m entioned above play a central role. We start with a simple ontology for rep resenting objects and causal interactions between objects. Using this ontol ogy, up investigate a range of meanings for the terms of interest. Specific ally, we distinguish between function as effect on the environment, and a d evice-centred view of device function. In the former view, function is seen as an intended or desired role that an artifact plays in its environment. We identify an important concept called mode of deployment that is often le ft implicit, but whose explicit representation is necessary for correct and complete reasoning. We discuss the task of design and design verification in this framework. We end with a discussion that relates needs in the world to functions of artifacts created to satisfy the needs.