Abstract
With recent globalization in industries, the number of failures and troubles of products caused by using them in unexpected ways has increased. In order to avoid such troubles, it is necessary not only to assume various ways of use thoroughly, but also to verify whether the design plan can fulfill required functions when the product is utilized in those ways. From this point of view, the authors proposed a functional verification method considering ways of use based on qualitative modeling of behavior of entities and cause and effect relationships among physical phenomena using Petri nets. However, it is not possible to detect failures caused by cause and effect relationships that designers do not consider. Thus, it is important to predict cause and effect relationships automatically. This paper provides methods to classify events and cause and effect relationships and to model. By considering the state of the entity and the event, the seven types of minimum units composed various cause and effect relationships were defined and represented in Petri nets. This makes it possible to represent various cause and effect relationships.
