• 산업경영시스템학회지
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• 제38권3호
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• pp.8-13
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• 2015

One of the most usual indicators to measure the performance of any inventory policy is the mean physical stock. In general, when estimating the mean physical stock in periodic review inventory systems, approximate approaches are often utilized by practitioners and researchers. The mean physical stock is generally calculated by a simple approximation. Still these simple methods are frequently used to analyze various single stockpoint and multi-echelon inventory systems. However, such a simple approximation can be very inaccurate. This is particularly true for low service levels. Even though exact methods to calculate the mean physical stock have been derived, they are available for specific cases only and computationally not very efficient, and therefore less useful in practice. In literature, approximate approaches, such as the simple, the linear, and Simpson approximations, were derived for the periodic review inventory systems that allow backorders. This paper modifies the approximate approaches for the lost sales case and evaluates the modified approximate approaches. Through computational experiments, average (and maximum) percentage deviations of mean physical stock between the exact method and the modified approximations are compared in the periodic review inventory system with lost sales. The same comparison between the modified and the original approximations are also conducted, in order to examine the performance of modified approximations. The results show that all modified approximations perform well for high service levels, but also that the performance may deteriorate fast with decreasing service level. The modified Simpson approximation is clearly better. In addition, the comparison between the modified and the original approximations in the periodic review inventory system with lost sales shows that the modified approximation outperforms the original approximation.

• 경영과학
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• 제19권1호
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• pp.107-116
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• 2002

A major challenge to supply chain managers is how to control inventories and costs along the supply chain while maximizing customer service Performance. In the literature, although the optimal management of inventory along the supply chain has received considerable attention during the past decades, the attention has been mainly given to multi-echelon control policies. A prerequisite for applying these policies is full information transparency in the supply chain, which is hard to accomplish in practice because it may require major organizational chanties. In the case that a decentralized control (local (R, S) policy) should be used at each location in multi-stave distribution systems, this paper presents the coordinating approach of determining the best policy which satisfies predetermined target customer service levels and minimizes the mean physical stock along the system.

• 산업융합연구
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• 제1권1호
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• pp.143-157
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• 2003

This paper examines the changed consumer perception to internet based channel. Internet based channel has time merit, place merit, assortment merit, compatibility merit, and so on. For seller, in the mean while, it has merits in the way of diminishing physical distribution cost, promotion cost, and reaching globally in the same time. In spite of so many merits of internet based channel, there were many types complain in past. Most of all, consumers expect that it will provide low-price merit to consumer, because it doesn't need shop, warehouse, stock, etc. Based on the empirical analyses in past, it didn't work, especially to price oriented consumer's perception. But in this research, it shows changing consumer's perception. Comparing past data with current data, we found outstanding gross in price related variables figure. But, in goods delivery related factors and personal credit information related factor, consumer recognized much more negatively yet. So, we conclude that even though some factors show improved perception, there are tasks to solve. We will observe the tuning point at that time.

• 농업과학연구
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• 제10권1호
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• pp.9-21
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• 1983

참나무 임분구조(林分構造)를 그 임분(林分)의 생산성(生産性)과 관련(關聯)시켜 분석(分析)하였다. 해발고(海拔高)에 따른 입지조건(立地條件)에 의(依)해 분류(分類)된 3개(個) 조사구(調査區)가 부여군(扶餘郡) 은산면(恩山面) 나령리(羅嶺里)에 위치(位置)한 참나무 임분(林分)에서 선정(選定)되었다. 임분(林分)의 입지조건(立地條件)은 몇가지 토양이화학적(土壤理化學的) 성질(性質)에 비추어 보통인 것으로 추정(推定)되었다. 굴참나무가 조사(調査)된 임분(林分)의 식생구성(植生構成)에서 우점종(優占種)이었다. 임분(林分)의 소밀도(疎密度)는 plot I의 65.4%에서 plot III의 78.2%까지 변이(變異)를 보였으며 참나무가 차지한 몫들은 plot I의 44.4%에서 plot III의 65.9%까지 이었다. 소밀도(疎密度)와는 달리 참나무류(類)의 축적(蓄積)은 plot I의 $3.937m^3$ (plot 전체(全體)의 73.4%)에서 plot III의 $2.075m^3$ (plot전체(全體)의 84.3%) 까지 이었다. 수형급별(樹型級別)로 측정(測定)된 그 점유비(占有比)는 수관투영면적(樹冠投影面積)과 재적간(材積間)에 상이(相異)했고 또한 plot 별(別)로 다른 pattern을 나타냈다. 개체목(個體木)들의 수관투영면적(樹冠投影面積)과 재적간(材積間)에 plot 별(別)로는 높은 유의성(有意性)이 인정(認定)되었지만 수형급별(樹型級別)로는 인정(認定)되지 않았다. 참나무의 수고(樹高), D.B.H.와 재적(材積)에 있어 누적생장량(累積生長量), 연년생장량(連年生長量), 총평균생장량(總平均生長量)은 plot 별(別), 수형급별(樹型級別)로 상이(相異)한 pattern을 보였다. 수고(樹高)의 연년생장(連年生長) 최대치(最大値)는 보통 D.B.H. 보다는 빨리 10~20년(年)내에 냐타났다. 수고(樹高), D.B.H. 재적(材積)의 총평균(總平均) 생장량(生長量)은 대략 10년(年) 이후(以後)부터 비슷한 수준(水準)을 유지(維持)하면서 불규칙(不規則)하게 변동(變動)했다. 간벌(間伐)에 따른 수관투영면적(樹冠投影面積)과 재적(材積)은 A 종(種)$90m^3$ 정도(程度)로 추정(推定)되었다.