• 대한안전경영과학회지
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• 제8권3호
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• pp.115-123
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• 2006

The main focus of this study is to investigate the performance of a clark-scarf type multi-echelon serial supply chain operating with a base-stock policy and to optimize the inventory levels in the supply chains so as to minimize the systemwide total inventory cost, comprising holding and backorder costs as all the nodes in the supply chain. The source of supply of raw materials to the most upstream node, namely supplier, is assumed to have an infinite raw material availability. Retailer faces random customer demand, which is assumed to be stationary and normally distributed. If the demand exceeds on-hand inventory, the excess demand is backlogged. Using the echelon stock and demand quantile concepts and an efficient simulation technique, we derive near optimal inventory policy. Additionally we discuss the derived results through the extensive experiments for different supply chain settings.

• Management Science and Financial Engineering
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• 제19권1호
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• pp.17-23
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• 2013

It has been studied that retailer's using a suboptimal (R, T) policy is often more desirable to make the best use of information flows than the locally optimal (s, S) policy in a two-stage serial supply chain. In this paper, by performing an extensive computational study, we tabulate the benefit of the retailer's using (R, T) policy instead of (s, S) policy in a supply chain with information sharing, and compare it to a maximum possible benefit that could be achieved in a centralized supply chain. We can understand the mechanisms of how the cost parameters and demand variance affect the benefit of the retailer's using (R, T) policy instead of (s, S) policy, by comparing decentralized and centralized systems.

• 대한안전경영과학회지
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• 제16권4호
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• pp.323-330
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• 2014

Various inventory control theories have tried to modelling and analyzing supply chains by using quantitative methods and characterization of optimal control policies. However, despite of various efforts in this research filed, the existing models cannot afford to be applied to the realistic problems. The most unrealistic assumption for these models is customer demand. Most of previous researches assume that the customer demand is stationary with a known distribution, whereas, in reality, the customer demand is not known a priori and changes over time. In this paper, we propose a reinforcement learning based adaptive echelon base-stock inventory control policy for a multi-stage, serial supply chain with non-stationary customer demand under the service level constraint. Using various simulation experiments, we prove that the proposed inventory control policy can meet the target service level quite well under various experimental environments.

• 유통과학연구
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• 제16권7호
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• pp.35-45
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• 2018

Purpose - The study investigates the impact of consignment on the economic performance in the supply chain with three stages. Through the analysis on distinct forms of consignment application, this study intends to answer to the question of how the consignment should be used in the multi-stage supply chain. Research design, data, and methodology - The proposed mathematical model represents the supply chain system with a manufacturer, a wholesaler, and a retailer. Three different forms of consignment application are considered depending on which stages adapt the consignment, and their system profits are compared with the traditional non-consignment system in numerical examples. Results - The numerical examples show that the serial consignment application performs better than any other forms of consignment as well as the non-consignment system. The additional analysis indicates that the system profit is significantly sensitive to the consignment rate. Conclusions - The outcome of this study implies the potential of consignment to improve the system performance even in the multi-stage supply chain system. Meanwhile, each supply chain member's preference to the specific form of consignment application could be different depending on which stage he has. All the supply chain members should jointly determine the appropriate consignment rates to obtain the best system performance.

• Management Science and Financial Engineering
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• 제10권2호
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• pp.29-51
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• 2004

In this paper, the cost impact of incorrect assumptions about the demand process in a supply chain in which there are two participants, a retailer and a manufacturer, is considered. When participants in the supply chain do not notice serial correlation in the demand process, they would turn to a simple inventory model based on an i.i.d. demand assumption. A mathematical model that allows us to quantify the cost incurred by each participant in the supply chain, when they implement inventory policies based on correct or incorrect assumptions about the demand process, is developed. This model enables us to identify how much it differs from the optimal costs.

• 한국시뮬레이션학회논문지
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• 제15권3호
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• pp.39-47
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• 2006

대부분의 공급망 계획에서 사용되는 각 계획 기간 내의 예측수요는 확정적인 것으로 간주한다. 그러나 현실에서 주어진 계획 기간 내의 수요 예측값은 확률적으로 분포를 따르는 것이 일반적이다. 본 연구는 기존의 안전재고를 통한 서비스 수준을 관리하는 방법을 대신하여 고객 수요의 분포내의 특정한 값을 수요 예측값으로 사용하는 수요선택 방법에 대해 다룬다. 수요 분위수와 계층 재고의 개념을 활용하여 서비스 수준 제약이 존재하는 시리얼 재고시스템을 대상으로 비교적 간단하지만 효과적인 수요선택을 위한 휴리스틱 알고리듬을 제안한다. 시뮬레이션을 활용한 비교 실험을 통해 제안된 알고리듬이 최적해와 유사한 매우 정확한 결과를 보임을 입증하였다.

• 한국시스템다이내믹스연구
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• 제12권1호
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• pp.115-130
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• 2011

This study shows the operational availability(Ao) analysis of the supply chain with maintenance functions using the system dynamics simulation. The simulation uses 60 equipments which are serial systems composed by 4 major components. And every entities are connected each other by causal loops. So whole simulation executed like one organic system. Specially we consider 2 constraints, one is the number of spare parts and the other is maintenance capacity level. 2 constraints have 11 levels each so the simulation has 121(11*11) scenarios which scenario has 30 different random number seed. The simulation executed total 3,630(11*11*30) times. We analysis average Ao of total equipments by 121 scenarios and additionally the regression of the average Ao and 2 constraints. As the result, we can get the more accurate values by the system dynamics simulation than the regression to analysis complex system like the supply chain with maintenance functions.

• 벤처창업연구
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• 제11권3호
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• pp.17-25
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• 2016

본 연구에서는 ICT(Information and Communications Technologies) 분야의 창업초기 벤처기업 300개에 대한 설문조사를 통해 국내 벤처생태계에서 연쇄창업의 현황, 행태, 성과에 대하여 분석하였다. 연구결과, 국내 연쇄창업의 비율은 약 18.7%였으며, 창업활동년수는 평균 약 8년, 연쇄창업가 중 약 80%는 같은 업종에서 재창업하였다. 연쇄창업은 신진창업보다 여러 명이 공동으로 팀을 이루어 창업하는 비중이 높고, 더 큰 규모로 시장에 진입하며, 대량생산으로 시장점유율을 높이는 경영전략을 더 중시하는 것으로 나타났다. 협력 상대로 공급 업체, 수요업체의 비중이 신진창업보다 높았으며, 정부와의 협력 비중은 낮았는데 정부로부터 자금지원을 받기보다 판로와 마케팅에 대한 지원을 받는 비율이 신진창업보다 높게 나타났다. 설립 첫해 당기순이익으로 재무적 성과를 회귀분석한 결과, 연쇄창업시에 공동창업하는 경우 재무적 성과가 상승하였으며, 업종을 변경하는 경우에는 성과가 하락하였다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
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• pp.441-445
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• 2004

In this paper, we deal with an inventory model of a multi-stage, serial supply chain system where a single product type and nonstationary customer demand pattern are considered. The retailer and suppliers place their orders according to an echelon-stock based replenishment control policy. We assume that the suppliers can access online information on the demand history and use this information when making their replenishment decisions. Using a reinforcement learning technique, the inventory control parameters are designed to adaptively change as the customer demand pattern is altered, in order to maintain a given target service level. Through a simulation based experiment, we verified that our approach is good for maintaining the target service level.

• 아태비즈니스연구
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• 제2권2호
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• pp.36-60
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• 2011

Radio frequency identification(RFID) is a system of technology that transmits digitally coded identity information in the form of a unique serial number of an object or person wirelessly, using radio waves. The primary use of RFID has been in asset tracking. This makes it highly useful across various industries for effective and efficient conduct of different business processes like supply chain management (SCM). As the use of RFID expands, the use of this technology is observed in such industries as transportation, traffic payment, hospital and medical care, education, and retail. Although this technology offers immense potential, it faces multifarious roadblocks, particularly in developing countries like India. Under this backdrop, this paper attempts to present an overview of the use and application RFID technology in India with a highlight on business-ecosystem for RFID in India. We also present various technical and non-technical challenges in the implementation of RFID in India.