Abstract
When a designer finds a problem during a development process, and effective way of ensuring the security and safety of the product is to identify all the possible causes of the problem by FTA and fix them. Although FTA is an effective method, it is not easy for a designer to construct a complete fault tree without any misunderstanding or oversight. Quantity dimension indexing is the method which verifies consistency of a fault tree automatically by comparison of quantity dimension. This paper describes two result. First, how to verify the correct quantity dimension. Before, there were cases when one phrase had the plural interpretation, a designer had to index the quantity dimension to the phrase manually. The task requires a designer the amount of time and labor. So, this paper describes methods of consistency verification by searching all over the fault tree. Second, new automatic indexing method. FTA often overlook the dynamic fault event. So, it has been proposed the classification about the qualitative fault value, but it is not clear how to indexing automatically. The paper also describes the method of automatic indexing the qualitative fault value.
