Abstract
The aim of this paper is to build a investment function model to describe the computer investment of the large banks in Japan based on the life cycle of the information system. This model is a kind of replacement investment theory. The first prototype of this model was introduced in Kamiyama[1997], in which the data from the Machine Order Statistics was used. As this data includes many third industries, the each different life cycle offsets each other. In this paper, another data is used to improve this problem.
