Abstract
This study proposes a modular design method that considers defense from leakage of the synthetic function. Today's modular design method might lead to an increase in of the leakage of intellectual property. If the modular design were able to conceal the structure of the interactions of product components which realize the product functions, the competitive value of synthetic function might be protected and its life might be extended in the market. The proposed method was implemented to a prototype system (the paper feeder on a photocopier). The result showed the Pareto solution for the trade-offs of manufacturing cost reduction through outsourcing and the defense against the leakage of synthetic function value, indicating a module division plan with both aspects balanced at a high level. The comprehensive evaluation confirmed that the proposed balanced plan accounted for a more satisfactory evaluation value than the other two plans. These application results support the hypothesis that modular design can conceal the structure of functional interactions. Therefore, it was concluded that the proposed module design method was more effective than the existing method, which does not consider the hiding and concealing of the functional interactions of the synthetic value.