Modeling for the simulation of inventory control utilizing computers

The inventory problem is now one of the most important issues in the Operational Research OR field. This paper examines inventory controls with different types of computers by constructing their simulation models. Two different types of software are employed in practice, namely Lotus 1-2-3 (spreadsheet) on personal computer which is easy in coding and SLCS IV (Simulation Language for Continuous System IV: almost the same type of simulation language as DYNAMO) on main frame computer which is for systems dynamics analysis. In each case the formation of algorithms and the coding are examined. First of all the basic theory and knowledge of inventory control are reviewed for modeling. And the ways of producing algorithms and the programming by macro-commanded of the spreadsheet are established, while a practical way of programming by SLCS IV is introduced. After that the simulation result tries to prove these modelings usefulness. The results of this paper are the following: (1) As modeling by Lotus 1-2-3 is easier in coding than by general programming languages, applying Lotus is very effective for beginners to concentrate on learning the theory or conception of inventory control and the basics of algorithms which is necessary for modeling on computers. Furthermore, it is possibly easy to excute simulation in a practical use. (2) In the case of applying SLCS IV the modeling in a practical use is comparatively easy if its function and procedure are understood enough in a complex case of inventory control model. [In Japanese.]