Organizational theory includes many theoretical models that explain, in a logical manner, the mechanisms behind an organization's adaptive behavior to the environment. Here, considering that the research target of organizational theory is the real world where management phenomena occur, the evaluation of models should not only examine their ability to explain, but also their applicability to the real world. In this paper, we construct a model of an organization's adaptive behavior under a dynamic environment by combining existing theoretical models in organizational theory. We also research the motorcycle industry as a case study to test the hypotheses derived from this model. Case-study research, however, while making descriptive models more persuasive by presenting specific examples, has shortcomings in terms of methodology. For this reason, we also performed computer simulations to supplement our findings by case-study research. We show that using the positive features of both approaches in a pluralistic manner is an effective method for verifying hypotheses.

The environment that organizations face is now changing rapidly. The purpose of this paper is to propose a conceptual model of management for adapting to such a changing environment from the viewpoint of systems theory. The model consists of mutual dependent four activities, that is, the discovery of distinctions, the creation of practices, self-organization, and self-control. Its characteristic is to produce continuously organizational change in real world through individual and organizational learning in conceptual world. In particular, the positive effects of conversations among members on the management and the role of information systems in the management are considered.

We propose a user-participated modeling method based on soft systems approach. We can analyze and improve business processes with the method. Especially, we focus our attention on OFP (Order Fulfillment Process) that starts at the order from customer and terminates at the distribution of products or services. And we design and install the system that improves OFP based on the user-participated modeling method. The system includes three subsystems, modeler, simulator and analyzer. Then, we apply the system to three business processes. The results of our experiment show that the system is useful to analyze and improve OFP.

While the world economy is becoming increasingly more borderless, the firms are exposed to the fierce global competition. In order for the firms to survive in this environment, the efficient use of information systems is critical and indispensable. However, the quantitative evaluation of its effect is very difficult, which, in turn, makes the executives' decision on informatization-related investment even harder.

In this paper, the quantitative analysis of informatization is carried out for each industry, with focus on its labor-saving effect. The capital stock associated with information systems is defined as informatization stock, and its slack is detected by DEA (Data Envelopment Analysis). Using this slack as indicator for inefficiency of information systems, its relationship to the marginal rate of substitution for labor input is analyzed. The result shows that the slack can be seen when the increase of informatization stock exceeds the marginal rate of substitution and/or the labor input is not reduced in proportion to the increase of informatization stock.

An extra inventory comes from over production, and the over production is caused by a so called "Bullwhip Effects", which presented by Prof. Hau L. Lee(Stanford University). Recently, CRP(Continuous Replenishment Planning) and VMI(Vendor Managed Inventory) introduced by many world class manufacturers, so that to share information in lower installation and prevent the Bullwhip Effect. Prior to this practice, many researches published papers analyzing the benefits of information sharing in serial inventory system. However, there are few papers for arborescent inventory system. Our purpose of this research is to analyze the benefits of information sharing in the sense of reduction of average inventory. Our result shows that the benefits of information sharing in lower installation are smaller than that in higher installation. We also found that the relative benefits of information sharing are weakened under the conditions of large lead time and large demand deviation.