• 산업경영시스템학회지
• /
• 제33권4호
• /
• pp.69-78
• /
• 2010

Multi-criteria ABC inventory classification is one of the most widely employed techniques for efficient inventory control, and it considers more than one criterion for categorizing inventory items into groups of different importance. Recently, Ramanathan (2006) proposed a weighted linear optimization (WLO) model for the problem of multi-criteria ABC inventory classification. The WLO model generates a set of criteria weights for each item and assigns a normalized score to each item for ABC analysis. Although the WLO model is considered to have many advantages, it has a limitation that many items can share the same optimal efficiency score. This limitation can hinder a precise classification of inventory items. To overcome this deficiency, we propose a context-dependent DEA based method for multi-criteria ABC inventory classification problems. In the proposed model, items are first stratified into several efficiency levels, and then the relative attractiveness of each item is measured with respect to less efficient ones. Based on this attractiveness measure, items can be further discriminated in terms of their importance. By a comparative study between the proposed model and the WLO model, we argue that the proposed model can provide a more reasonable and accurate classification of inventory items.

• 한국시뮬레이션학회논문지
• /
• 제24권1호
• /
• pp.1-8
• /
• 2015

본 연구는 다양한 공급망 내 재고관리 방법 중 최적의 방법을 찾아내는 것을 목적으로 하고 있다. 비교대상 재고관리 방법은 Min-Max, 정기, 정량, 목표재고관리 방법으로 각 제품별 리드타임과 수요를 달리하여 구성하였다. 또한 공급사슬 망의 단계가 2단계인 경우와 3단계인 경우를 구분하여 공금망 단계를 줄였을 경우의 결과를 분석한다. 시뮬레이션 모형은 8개의 시나리오로 나뉘며, 각 시나리오는 주문방식과 단계로 구분할 수 있다. 시뮬레이션을 위한 입력 자료는 기존의 선행연구 결과와 실제데이터를 토대로 하였다. 시뮬레이션의 평가는 매출액, 총판매건수, 총배송비, 총결품량, 결품횟수, 결품손실금, 평균 재고량, 재고관리비, 순이익으로 실시한다. 시뮬레이션 결과 목표재고관리 방법이 가장 우수하게 나타났으며, 목표재고관리 시스템은 기존의 재고관리 방법을 사용한 시나리오보다 순이익 및 재고 등의 측면에서 우수한 결과를 나타냈다. 또한 기존의 공급사슬에서 한 단계 공급망을 줄였을 경우 수익이 증가하는 것을 확인할 수 있었다. 본 연구 결과는 목표재고관리 시스템을 추가적으로 고려하고 있다는 것과 공급사슬의 단계를 줄일 수 있는 개선 방안을 논의했다는 것에 의의를 둘 수 있다.

• 한국정보기술응용학회:학술대회논문집
• /
• 한국정보기술응용학회 2007년도 춘계학술대회
• /
• pp.198-208
• /
• 2007

Recently business enterprises have forced to face in fierce competition in today's global markets due to the short life cycles of products and the higher expectation of customers. Together with continuing advances in communications and transportation technologies, these environments have motivated the continuous evolution of the supply chain and the management techniques. This paper consider three-echelon inventory system which consist of one manufacturer, one distributor and N retailers for a single product under assumption of constant demand. This paper propose the inventory replenishment period using heuristic method and order policy through coordination of inventory replenishment period. The simulation results show that decrease the total cost of the three-echelon inventory system.

• Management Science and Financial Engineering
• /
• 제16권3호
• /
• pp.21-47
• /
• 2010

Quantity discounts provide a practical foundation for supply chain inventory policies, improving the supplier's profit and reducing the buyer's inventory cost simultaneously. Traditional quantity-discount research, which deals with inventory coordination between a buyer and a supplier, is extended to a stationary stochastic environment. This research shows that the magnitude of the optimal discounts scheduled by the deterministic quantity discount models may not be large enough to cover the buyer's additional inventory stocking risks under uncertain conditions. As a result, the buyer's total inventory cost may often increase rather than decrease. In contrast, the proposed model allows the supplier to identify the discount level, which shares the buyer's amplified risk associated with temporary overstocking and ensures that both buyer and supplier benefit economically. The performance of the proposed model was tested in the continuous review environments via numerical experiments. The experimental results support the proposed method as a feasible alternative in coordinating inventory decisions under stochastic demand.

• 한국지능시스템학회논문지
• /
• 제11권7호
• /
• pp.584-590
• /
• 2001

An inventory management system of manufacturing industry has a model of different kinds according to the objective and the situation. An inventory management system needs superior system technique in demand forecast, economical efficiency, reliability and application for stable supply of the finished goods, the raw materials and the parts. This paper proposes a demand forecast method based on fuzzy structured neural network, which uses min-operation and trapezoid membership function of fuzzy rules. So we can construct an intelligent inventory management system that make optimized decision-making for forecasting data with expert s opinion in fuzzy environment. The inventory management system uses intelligence agent and it could be adapted to a system environment change in order.

• 산업공학
• /
• 제13권4호
• /
• pp.584-590
• /
• 2000

In this paper, we analyze the inventory and inspect cost of small-to-medium-sized enterprises which are getting orders from large enterprises using JIT(just in time) system. So far, we have not found the good inventory and inspect cost formula for the small-to-medium-sized enterprises. In this paper, we first survey the inventory and inspect strategy and cost formula of the small-to-medium-sized enterprises in this country. We are trying to mathematical modelling of several cases depending on the inventory and inspect strategy of large enterprises. We suggest inventory and inspect several cost formula by using the method minimizing the total cost of the small-to-medium-sized enterprises. We also give some numerical examples for your understanding.

• 한국대기환경학회지
• /
• 제30권1호
• /
• pp.26-36
• /
• 2014

The uncertainty assessment is important to improve the reliability of emission inventory data. The DARS (Data Attribute Rating System) have recommended as the uncertainty assessment technic of emission inventory by U.S. EPA (Environmental Protection Agency) EIIP (Emission Inventory Improvement Program). The DARS score is based on the perceived quality of the emission factor and activity data. Scores are assigned to four attributes; measurement/method, source specificity, spatial congruity and temporal congruity. The resulting emission factor and activity rate scores are combined to arrive at an overall confidence rating for the inventory. So DARS is believed to be a useful tool and may provide more information about inventories than the usual qualitative grading procedures (e.g. A through E). In this study, the uncertainty assessment for 2009 CAPSS (Clean Air Policy Support System) emission inventory is conducted by DARS. According to the result of this uncertainty assessment, the uncertainty for fugitive dust emission data is higher than other sources, the uncertainty of emission factor for surface coating is the highest value, and the uncertainty of activity data for motor cycle is the highest value. Also it is analysed that the improvement of uncertainty for activity data is as much important as the improvement for emission factor to upgrade the reliability of CAPSS emission inventory.

• 한국국방경영분석학회지
• /
• 제24권1호
• /
• pp.176-188
• /
• 1998

In this paper, it is identified that the optimal level of each performance measures (service and inventory level) is not sensitive to an uncertain environment under JIT Kanban system designed by Moeeni. Moreover, it is proposed that the optimal design method considering multiple performance characteristics is the optimal level decision method according to the relative importance differences of each performance when there exist multiple performance characteristics. The result from the simulation analysis shows that the number of Kanban for stage 3 (final process) and stage 2 is increased at the service level. It is found that the expected loss is minimal when the cycle time decreases and the container size increases. However, the stage 1 is not affected by the number and cycle time of Kanban. It is thus important to consider carefully the cycle time and the container size of the Kanban to satisfy the demand in right time. In case of inventory level, the working inventory level decreases when the container size is decreased and the working inventory level also decreases slightly when the cycle time of the Kankban is increased in stage 1 and 2.

• 산업경영시스템학회지
• /
• 제27권4호
• /
• pp.110-116
• /
• 2004

ABC analysis is the process of dividing inventory items into three classes according to their monetary usage so that managers can focus on items that have the highest monetary usage value, and has been widely used in practice since its development in 1950. However, the original criterion, monetary usage value, can no longer be the only rational criterion. Applying Analytic Hierarchy Process, we develop a new method to classify inventory items by considering such operationally/strategically important criteria as annual dollar usage, lead time, supplier's capacity, defective rate, difficulty of purchasing and unit price. A case study is performed applying the method to the field data from a company which produces electrochemical products.

• 반도체디스플레이기술학회지
• /
• 제22권2호
• /
• pp.104-111
• /
• 2023

The semiconductor industry, which relies on global supply chains, has recently been facing longer lead time for material procurement due to supply chain uncertainties. Moreover, since increasing customer satisfaction and reducing inventory costs are in a trade-off relationship, it is challenging to determine the appropriate safety stock level under demand and lead time uncertainties. In this paper, we propose a framework for determining safety stock levels by utilizing the optimization method to determine the optimal safety stock level. Additionally, we employ a linear regression method to analyze customer satisfaction scores and inventory costs based on variations in lead time and demand. To verify the effectiveness of the proposed framework, we compared safety stock levels obtained by the regression equations with those of the conventional method. The numerical experiments demonstrated that the proposed method successfully reduces inventory costs while maintaining the same level of customer satisfaction when lead time increases.