Isao Tsushima

Evaluation of optimal ordering method for coupling point production system

A new ordering system aims to prevent running out of stock, to limit replenishment quantities and to keep reasonable stock levels for multiple items. In the lot-size re-order system and the interval re-order system, replenishment intervals or quantities are determined by each system after replenishment items are decided. When both re-order systems run for multiple items, the total replenishment quantity usually exceeds the limited capacity. The problem of limited capacity was solved by production scheduling or supply lead-time delay. We propose an optimal ordering method, to be controlled by the margin stock ratio under limited capacity. The margin stock ratio is defined by the prediction of the out-of-stock situation that is calculated by the available inventory stock and by the demand quantities of the supply lead-time period. After each item is arranged according to the margin stock ratio, replenishment items are determined under the limited capacity. This new method has been successfully applied to a window-frame manufacturing process.

Preliminary evaluation of business to business electronic commerce by using qualitative simulation and scenario generation

A scenario generator for qualitative simulation systems has been developed for explaining the influence flow to the concerned node in the structural model. The paper presents the method through which companies evaluate business to business electronic commerce (e-commerce) systems by using the scenario generator. The method consists of the following processes: the adjustment of the structural model to specific companies; the qualitative simulation and the scenario generation of the new systems; and the evaluation of the scenario. This method will be useful for companies to evaluate e-commerce systems.

A Resource Allocation Method and an Identification Method for Discrete Systems

Abstract This nor Loposea. a nov construction for resource allocation problem(RA-Problem). A new PA-problem concidering both job sequence and Material flow in given and solved. Job sequence and material flow are expressed as a network model. This paper also proposes an identification method for PERT arrow-digram, which is the most simplified network model. The proposed identification method is heuristic, but it can evaluate the validity of identified values. An example is also given where the proposed methods were applied in the designing of n warehouse system.