• Journal of information and communication convergence engineering
• /
• v.19 no.4
• /
• pp.221-227
• /
• 2021

An early warning system was developed to help identify stock status as early as possible. For performance to improve, there needs to be a feature to predict the amount of stock that must be provided and a feature to estimate when to buy goods. This research was conducted to improve the inventory early warning system and optimize the Reminder Block's performance in minimum stock settings. The models used in this study are the single exponential smoothing (SES) method for prediction and the economic order quantity (EOQ) model for determining the quantity. The research was conducted by analyzing the Reminder Block in the early warning system, identifying data needs, and implementing the SES and EOQ mathematical models into the Reminder Block. This research proposes a new Reminder Block that has been added to the SES and EOQ models. It is hoped that this study will help in obtaining accurate information about the time and quantity of repurchases for efficient inventory management.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.32 no.2
• /
• pp.99-107
• /
• 2007

We consider (worst-case) robust optimization versions of the Economic Order Quantity (EOQ) model with decreasing cost functions. Two variants of the EOQ model are discussed, in which the purchasing costs are decreasing power functions in either the order quantity or demand rate. We develop the corresponding worst-case robust optimization models of the two variants, where the parameters in the purchasing cost function of each model are uncertain but known to lie in an ellipsoid. For the robust EOQ model with the purchasing cost being a decreasing function of the demand rate, we derive the analytical optimal solution. For the robust EOQ model with the purchasing cost being a decreasing function of the order quantity, we prove that it is a convex optimization problem, and thus lends itself to efficient numerical algorithms.

• Journal of Korean Institute of Industrial Engineers
• /
• v.15 no.1
• /
• pp.17-21
• /
• 1989

The problem to determine Economic Order Quantity(EOQ) occurs when price discounts or uncharged additions are offered for the purchase in the unit of package. It is found that the annual inventory cost needs to be evaluated for at most three alternative order sizes to find EOQ, which is easier than the case of all-unit or incremental quantity discount. Numerical examples are presented.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.6
• /
• pp.653-661
• /
• 2017

This study compares and analyzes the operation costs of traditional and direct delivery strategies considering carbon emissions. For the determination of minimum operation costs and order quantity, we use the Economic Order Quantity (EOQ) model, which is the proper method for calculate the operation costs by logistics strategy. Using the classical EOQ model, we expand the EOQ model considering carbon emissions and domestic logistics environment. We conduct an empirical study on two agri-food logistics strategies under limitation of the carbon emissions using the expanded EOQ model. From the results of the empirical study, we find that the operation costs of direct delivery strategy are about 50% lower than those of the traditional strategy. Economic order quantity is also smaller than that of the traditional strategy. These results indicate that agri-food products can be transported quickly and freshly under direct delivery strategy. Consequently, considering carbon emissions, direct delivery logistics strategy are analyzed to have more positive effect on economic and environmental issues than existing logistics strategy. It is judged that direct strategy will also increase the freshness of agricultural products.

• Journal of Korean Society for Quality Management
• /
• v.20 no.1
• /
• pp.68-79
• /
• 1992

The economic order quantity(EOQ) is a robust quantity, and it is largely insensitive to reasonable errors in the estimation of most of its parameters. Optimal EOQ and reorder point which are not sensitive to the estimates of the various cost model parameters for Kim and Park's model are determined. This of Taguchi's parameter design which finds a robust EOQ and reorder point using reasonable cost structure on the assumption of normally distributed quality characteristic. A numerical example is also presented to illustrate the proposed procedure and computer aided numerical experiments for selected values of backordered fractions and standard deviations are performed.

• Proceedings of the Safety Management and Science Conference
• /
• 2005.11a
• /
• pp.511-515
• /
• 2005

기업은 고객이 원하는 시기에 원하는 제품을 구매할 수 있도록 항상 준비가 되어 있어야 한다. 고객의 수요를 만족시키기 위하여 기업은 다양한 수요예측방법을 통하여 적절한 재고 수준과 수요예측을 하고 있다. 제조 기업의 경우에는 다른 산업에 비하여 정확한 수요예측과 낮은 재고 수준의 유지가 비용과 직접적인 연관이 있기 때문에 제조 기업은 경제적인 주문량 결정(Economic Order Quantity: EOQ)이 매우 중요한 문제이다. 주문량을 결정하는 방법에는 여러 가지가 있지만, 본 논문에서는 고객 지연을 방지하기 위하여 경제적 주문량 결정에 고객 지연과 관련된 비용을 포함시키는 것은 물론 고객 지연이라는 상황을 방지하는 노력의 한 방법으로 가격 할인(discount system)을 이용하고자 한다. 가격 할인을 이용하여 고객으로 하여금 빠른 주문을 유도하고 그로 인하여 고객 지연 상황의 발생을 줄여보려고 한다.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.5
• /
• pp.532-541
• /
• 1997

This article derives an analytic solution to determine the optimal size of multiple noncontinuous process and storage units. The total cost to be minimized consists of the setup cost of noncontinuous processing units and the inventory holding cost of feedstock/product storages. A novel approach, which is called PSW(Periodic Square Wave) model, is applied to represent the material flow among non-continuous units and storages. PSW model presumes that the material flow between unit and storage is periodic square wave shaped. The resulting optimal unit size has similar characteristics with the classical economic lot sizing model such as EOQ(Economic Order Quantity) or EPQ(Economic Production Quantity) model in a sense that the unit size is determined as the balance between setup and inventory holding cost. However, the influence of inventory holding cost of PSW model is different from that of EOQ/EPQ model. EOQ/EPQ model includes only the product inventory holding cost but PSW model includes all inventory holding costs around the non-continuous unit with proportional contribution. PSW model is suitable for analyzing interlinked process-storage system. The optimal lot size of PSW model is smaller than that of EOQ/EPQ model. This is quitea remarkable result considering that the EOQ/EPQ model has been is widely used since last half century.

• Management Science and Financial Engineering
• /
• v.13 no.1
• /
• pp.35-53
• /
• 2007

We consider a(worst-case) robust optimization version of the Economic Order Quantity(EOQ) model. Order setup costs and inventory carrying costs are assumed to have uncertainty in their values, and the uncertainty description of the two parameters is supposed to be given by an ellipsoidal representation. A genetic algorithm combined with Monte Carlo simulation is proposed to approximate the ellipsoidal representation. The objective function of the model under ellipsoidal uncertainty description is derived, and the resulting problem is solved by another genetic algorithm. Computational test results are presented to show the performance of the proposed method.

• Journal of the military operations research society of Korea
• /
• v.23 no.2
• /
• pp.72-84
• /
• 1997

In this paper, we consider an economic order quantity(EOQ) and an optimal discount pricing policy for the monopsony related to the weapon system acquisition. In the monopsony case, a buyer wishes to maximize the profit. However, a seller wants to minimize the total inventory related cost since a buyer can determine the purchase price for the product. We develop a generalized version of EOQ model for the monopsony, including one seller-one buyer model and two seller-one buyer model. A model of buyer reaction to any given pricing scheme is developed to show that there exits a unified pricing policy which motivates the buyer to increase its ordering quantity per order, thereby reducing the joint(buyer and seller) ordering and holding costs in the system.

• Korean Journal of Construction Engineering and Management
• /
• v.12 no.1
• /
• pp.33-42
• /
• 2011

Part of material and inventory management is one of important factor for business interests. But importance of material and inventory management in domestic construction project has been relatively devalued. The existing study of inventory has been studied with limited individual factor about inventory management. Therefore construction material management needs improvement via an accurate prediction with whole and systematic process viewpoint. and existing theory of material and inventory introduction to construction from manufacturing needs reflecting characteristics about construction project. This paper suggests material management process for economic material management. This paper to make a unit curtain wall of case construction project comparison between total cost of existing material management process and total cost of economic order quantity of proposal material management process To verify usefulness of order point and order quantity determination process.