DIDS: rapidly prototyping configuration design systems

successively decomposes the artifact being designed along functional lines. It describes the functional relationship between the parts and abstract parts in the domain. This relationship describes how abstract parts may be realized by combining sets of lower-level functions, which may include parts. (4) R e q u i r e d f u n c t i o n s parts and abstract parts often require the functions performed by other parts to support their operation. This information is contained in the required-functions knowledge type. Associated with each function performed by a part is a list of required functions to support its operation, but which are not specified by the user. (5) At t r ibu t e constraints attribute constraints specify algebraic relationships between the attributes of parts and abstract parts that must be maintained. Constraints enable the problem solver to distinguish acceptable from unacceptable solutions, and to compute specification values. (6) Connec t i on constraints connection constraints restrict the set of possible connections that can be made among the ports of parts and abstract parts. They may either specify illegal connections, or sets of connections that have been found to be useful in the past. (7) A r r a n g e m e n t constraints arrangement constraints restrict how parts can be geometrically or topologically arranged. They define the (physical) relationships between the boundaries of parts and abstract parts. (8) Preference k n o w l e d g e preference knowledge