在庫模型의 一般化에 관한 한 試圖와 그 吟味 : F.W. Harris의 費用 方程式을 中心으로 = A Try for the Generalization of Inventory Model and Its Includings

다국어 초록 (Multilingual Abstract)

1) As early as 1915, cost equation for the determination of economic lot-size was developed first by F. W. Harris.
It was a mathematical model, worthy of. comparison with modern operations resarch (=O. R.) models.
The early model is still useful in developing insights into the problem of deciding what size lot to manufacture.
2) Lot-size might at first seem that the larger the lot-size, the better.
When each new lot is started, there are set-up costs involved.
The larger the lot, the smaller the unit set-up costs, for they will be spread over a large volume.
Another class of costs increase as the lot-size increases, and are known as carrying costs
They arise from the fact that the larger the number produced at one time, the larger the size of the inventory to be stored.
As the inventory in creases in size, there will be an inaease in the following carrying casts :
a. interest costs more money will be tied up in larger inventories
b. rental on storage space
c. property taxes and insurance
d. obsolence-the larger inventories increase the risk that these will become obsobet before these are used up or sold.
e. deterioration-certain items tend to deteirate in storage, and the larger the inventory, the longer the period of storage, and the greater the deterioration.
Two opposing sets of costs as described here are evident.
There will be a point where the total of the two will reach a minimum and this is the economic lot-size.
3) F. W. Harris used unreal assumptions in changing the relationship between such cost foctors into a cost equation:-the model will be realized that the assumptions made are not likely to be satisfied in practice.
Therefore, the model presents us the methodology of model construction and principal logic for determining economic lot-size. If it can be used more effectively in decision making for the determination, it is necessary to change such elementary model under the unreal assumptions and the specific situation in some degree into the model which is applicable in a geraeral situation, and obtain a similar cost equation.
Therefore, there papers are written by the results of the mathematical approaching to the derivation of the optimum lot-size under the generalized situations as followings :
(1) under the situation that management manufactures multi-product.
(2) under the situation that Ive consider production lead-time in modeling.
(3) under the situation of demand with uncertainty
(4) in case of refinement of inventory cost.
4) Though such modifications to the models are made without errors, there are very important problems in application for decision-making.
One of the problems is a very problem of usefulness in decision-making by using the model. In other word, when the models are applied for solving the problems in proctice, the figures derived by such formulas is not only a scientific point, and its functions are limited to giving the manager a more convenient position to make decision.
5) Now it is desired that such modifications should be made without errors, but with speed. Fortunately, the valid uses of high-speed computer are leading such a urgent problem to success.

목차 (Table of Contents)

• 一. 問題의 提起
• 二. F.W. Harris의 費用方程式과 經濟的「롯트」의 크기
• 1. 在庫費用分析
• (1) 販賣와 在庫費用
• ㄱ. 調達費用
• ㄴ. 在庫保有費用
• ㄷ. 在庫不足費用
• (2) 製造와 在庫費用
• ㄱ. 製造計劃費用
• ㄴ. 製造費用
• 2. 經濟的 「롯트」크기의 決定
• (1) Harris 模型-基本模型으로서-
• (2) Harris 模型의 限界와 意思決定上의 意義
• 三. 基本模型의 一般化
• 1. 多數品目의 境遇
• (1) 模型化 (2) 吟味
• 2. 製造 lead-time을 考慮하는 境遇
• -基本模型과의 差異分析과 그吟味를 中心으로-
• (1) 模型化 (2) 差異分析과 吟味
• 3. 需要가 不確實한 境遇
• -幾何學的接近-
• (1) 模型의 誘導
• (2) 安全在庫의 機能과 模型化
• ㄱ. 安全在庫의 機能
• ㄴ. 模型化
• ㄷ. 差異分析
• (3) 需要豫測誤差의 調整
• -調整在庫의 機能과 그 最適化-
• 4. 在庫費用을 細分化하는 境遇
• (1) 資本費用의 細分化와 그 模型化
• (2) 保管費用의 細分化와 그 模型化
• 四. 結論