Evaluating design using knowledge of purpose and knowledge of structure

A representation strategy that uses knowledge of both device purpose and structure is presented. The representation is described mainly as it relates to design evaluation. The design evaluation task, which checks that the structural design describes a device that will achieve its stated purpose, becomes difficult with even a small increase in complexity. A way to automate this aspect of device understanding, thus providing a systematic mechanism for evaluating the logical aspects of designing mechanical causal systems, is given. Implementation of these ideas in the Doris system is discussed.<>