An `AI in Design' View of Design
Methodology


Decomposition

Does the system use decomposition methods?

Discussion. Decomposition helps the system focus on smaller pieces, instead of dealing with the entire design problem at once [Liu & Brown 1994]. If specialized knowledge becomes available for any piece, it can be handled in more detail. Structural decomposition is used whenever the artifact can be decomposed in subcomponents. Functional decomposition is used to generate a set of elementary functions, which are then mapped to components [Lee et al. 1992] [Steinberg & Mitchell 1984]. Both types of decomposition are closely tied to the designed object. Task and goal decomposition are specific for the design process [Mittal & Araya 1992]. They also reflect the principle that smaller problems are easier to solve.


Does the system use recomposition methods?

Discussion. After decomposition, once decisions have been made about the smaller pieces of the design, they can be recomposed into a higher level object. Recomposing the individual items raises the problem whether they can actually be integrated in a single object and whether they are compatible [Maher 1985]. A set of physical subcomponents can be recomposed into an object which includes them. A set of functions found in a component can be recomposed in a higher-level function which represents the component [Steinberg & Mitchell 1984]. Recomposition needs to verify that the higher level entities (components, functions, behaviors etc.) are satisfied by the elements selected/determined at the lower levels.


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