• 산업경영시스템학회지
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• 제18권34호
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• pp.193-204
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• 1995

Many studies show that the value of the warehouse is good. However, studies explicitly mention the tradeoff between costs of operating the warehouse and benefits from the warehouse. Also, it is important to know when the benefits overcome the costs. We study a one-warehouse/N-retailer(s,Q) distribution system with stochastic lead times in order to answer two questions: "What are the optimal policies of the system that minimizes total system costs\ulcorner" and given the optimal policies, "Is the value of the warehouse always good\ulcorner" We use an analytical model for answering the questions. We find that the optimal policies are different from those with deterministic lead times. In fact it is reverse. We alse find the existence of the breakeven point beyond which the benefits starts overcomming the costs. And, we show that one of the breakeven points is the mean ratio of a supplier's lead time to transportation lead time between the warehouse and the retailer. Finally, we show that the breakeven point is sensitive to the ratio of holding costs of the warehouse and the retailer and it is also sensitive to the unit backorder costs at the retailer.sts at the retailer.

• 한국철도학회논문집
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• 제12권6호
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• pp.996-1010
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• 2009

본 논문은 우리 실정에 맞고 국제비교에도 활용할 수 있는 국가차원의 교통계정 기본틀을 제시하였다. 기본틀은 비용 수입항목과 산정 방법론으로 구성되어 있다. 그리고 제시된 우리나라의 교통계정을 적용해본 결과, 국내총생산 대비 도로교통의 총비용은 유럽보다 3.23% 높은 것으로 나타났고 철도교통의 총비용은 유럽보다 0.67% 낮은 것으로 나타났다. 또한 도로교통과 철도교통의 단위당 비용을 비교한 결과, 여객의 인-km당 도로교통 비용이 철도교통 비용의 약 4.8배, 화물의 톤-km당 도로교통 비용은 철도교통 비용의 약 2.4배로 나타났다.

• 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.