Abstract
In order to realize a CAD system, a design model, a control method of a design process, and a reprentation method of design knowledge for the design model must be concreted. The previous paper describes a boundary factor model as the design model and the Petri net as the control method. This paper reports on the representation method of the design knowledge for the design model. A new representation method, “Object and Operation Dualism”, is adopted for the design model. Object and Operation express designing know how, formulations, programs, tables, and so on. And, Object and Operation together become an information flow moving through machine units. It is regarded that a set of Object and Operation builds up the machine unit. The Petri net method controls the information flow. Object and Operation are coded in a similar way to a frame representation here. Examples show how Object and Operation are built in the design model for the description of the design knowledge, and how they are controlled by the Petri net.
