• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.742-749
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• 2002

This paper deals with a continuous-review two-echelon inventory model with one-for-one replenishment and Poisson demand where transshipments among retailers are allowed. Two classes of inventory systems are considered by the number of distribution centers(DCs) which provide each retailor with inventory items. 1:N class inventory system and M:N class inventory system respectively. Two-phase model is constructed to find out the optimal inventory positions which minimize supply chain costs. Approximations for customer service levels of the system are evaluated in the first phase, and the optimal inventory positions are found subject to the constraints for service level in the second phase. Simulation tests are performed to assure the effectiveness of the proposed model. The effect of transshipment is evaluated.

• Journal of the Korean Operations Research and Management Science Society
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• v.36 no.3
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• pp.61-74
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• 2011

The objective of this study is to evaluate the effects of sharing uncertain yield information with a downstream supply chain player. We are interested in understanding how the amount of yield uncertainty affects the supply-side benefits and/or costs, which has not been considered in the literature, in addition to the customer-side benefits. With that purpose, this work evaluates a supplier who provides yield information in comparison with another supplier who shares no information. We simulate an order-up-to type heuristic policy that is adapted from the literature and reasonably modified to represent yield information sharing with error. From the simulation study, we argue that the customer would experience cost reduction, but the cost for supplier's inventory is increasing when sharing yield information. Furthermore, the amount of benefits and costs are situational and affected by level of yield uncertainty and demand variance. Based on the simulation study, we finally make several recommendations for the supply-side approaches to yield information sharing.

• Industrial Engineering and Management Systems
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• v.2 no.1
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• pp.28-34
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• 2003

The fundamental design issues that arise in the pickup and delivery system planning are optimizing the system with minimum cost and maximum throughput and service level. This study is concerned with the development of pickup and delivery system with customer responsive service level, DCM(Demand Chain Management). The distribution process and service map are consisted of manufacturing, warehousing, and pickup and delivery. First we formulated the vehicle pickup and delivery problem using GIS-VRP method so as to satisfy the customer service requests. Second, we developed a GUI-type computer program using AVL, automated vehicle location system. The computational results show that the proposed method is very effective on a set of test problems.

• Journal of the Korean Operations Research and Management Science Society
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• v.31 no.1
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• pp.91-103
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• 2006

Given a bill of materials (BOM) tree T labeled by the breadth first search (BFS) order from node 0 to node n and a general network ${\Im}=(V,A)$, where V={1,2,...,m} is the set of production facilities and A is the set of arcs representing transportation links between any of two facilities, we assume that each node of T stands for not only a component. but also a production stage which is a possible stocking point and operates under a periodic review base-stock policy, We also assume that the random demand which can be achieved by a suitable service level only occurs at the root node 0 of T and has a normal distribution $N({\mu},{\sigma}^2)$. Then our integrated model of facility location problems and safety stock optimization problem (FLP&SSOP) is to identify both the facility locations at which partitioned subtrees of T are produced and the optimal assignment of safety stocks so that the sum of production cost, inventory holding cost, and transportation cost is minimized while meeting the pre-specified service level for the final product. In this paper, we first formulate (FLP&SSOP) as a nonlinear integer programming model and show that it can be reformulated as a 0-1 linear integer programming model with an exponential number of decision variables. We then show that the linear programming relaxation of the reformulated model has an integrality property which guarantees that it can be optimally solved by a column generation method.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.41-49
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• 2015

This study explores the possibility of innovative government's administrative services to the public by reflecting the social implications of 'Big Data'. In particular, the idea of OPP (Order Penetration Point) and SOP (Service Offering Point) as a management scheme for the extension of administrative processes into the resident's living space is proposed to overcome the inherent limits of e-government service quality, the root cause of which is believed in the segregation of two spaces - the resident's living space and the government's offices. Furthermore, a discussion is made on how to integrate sensor data from the resident's living space with traditional administrative database, which is a new challenge in the course of synchronizing the two spaces. The implications on the process extension are also provided centering around the shift from reactive to proactive services.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.38 no.3
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• pp.117-126
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• 2015

This paper is to analyze an integrated production and inventory model in a single-vendor multi-buyer supply chain. The vendor is defined as the manufacturer and the buyers as the retailers. The product that the manufacturer produces is supplied to the retailers with constant periodic time interval. The production rate of the manufacturer is constant for the time. The demand of the retailers is constant for the time. The cycle time of the vendor is defined as the elapsed time from the start of the production to the start of the next production, while the cycle times of the buyer as the elapsed time between the adjacent supply times from the vendor to the buyer. The cycle times of the vendor and the buyers that minimizes the total cost in a supply chain are analyzed. The cost factors are the production setup cost and the inventory holding cost of the manufacturer, the ordering cost and the inventory holding cost of the retailers. The cycle time of the vendor is investigated through the cycle time that satisfies economic production quantity with the production setup cost and the inventory holding cost of the manufacturer. An integrated production and inventory model is formulated, and an algorithm is developed. An numerical example is presented to explain the algorithm. The solution of the algorithm for the numerical examples is compared with that of genetic algorithm. Numerical example shows that the vendor and the buyers can save cost by integrated decision making.

• The Journal of the Korea Contents Association
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• v.9 no.7
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• pp.184-192
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• 2009

CT(Culture Technology) became one of the leading industries with fast growth in its contribution to an economy not only in Korea, but also in the world. This study suggests policy direction and priority of CT in the perspective of technology standardization and its classification. As a result, this study proposes a new 'CT Classification' using the value chain concepts contrary to previous classification. In addition, we suggest standardization priority, especially, in the sectors of 'CT Distribution/Service', 'CT Marketing', 'General CT management' based on our survey research of production side. Consequently, our research suggests an important strategic bases for decision makers in CT policy and development both government and private sectors.

• Korean Journal of Construction Engineering and Management
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• v.6 no.3 s.25
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• pp.144-155
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• 2005

Since 1950s, the Korean housing market has continually experienced the chronicle lack of housing stock because of lower housing investment in comparison with a population explosion, prompt urbanization and rapid restructuring of family. The Korean housing market have thus been driven not by the pricing model by housing demand-supply chain but by the Korean housing policies focusing on the increase of housing supply and the living stability of the middle or low-income bracket. After all, repetitive economic vicious circle of housing price and the increase of unsold apartments aggravated the malfunction of the Korean housing market. Meanwhile, the Korean construction firms have exacerbated their profitability. Such terrible situations are mainly triggered by the Korean construction firms that weighed on the short-term profits and quick response of the government policy alterations rather than the prospect of housing market Therefore, this research focusing on the dynamics of housing market identified and classified the demand and supply elements that consist not only of housing system structures but also of the environmental elements that affect the structures. Based on the system thinking and traditional theory of consumer's choice, the interactions of these elements were constructed as a causal loop diagram that explains the mutual influences among housing subsystems with feedback loops. This paper describes and discusses about the causes of the dynamic changes in the Korean housing market. This study would help housing suppliers, including housing developers, construction firms, etc., to form a more comprehensive understanding on the fundamental issues that constitute the Korean housing market and thereby increasing their long term as well as minimizing the risk involved in the housing supply businesses.

• Journal of the Korea Safety Management & Science
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• v.15 no.1
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• pp.183-191
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• 2013

After the Uruguay Round, Korean agriculture industry has been protected and reared with government grants. However, until now there has been very minimal development to establish a solid export industry which can make the most of the trade agreements in place. There has been much research on ways to expand agricultural exports in order to respond properly to this ever changing environment and sustainable agricultural industry. As all other export industries, an efficient logistics network is paramount in order to allow the agricultural industry to respond to changes in demand and penetrate global markets. The lack of systematic logistics activities such as packaging, transportation, unloading, storage, and information transfer in farms has been a major factor in the inefficiency of the agricultural industry resulting in minimal development. From this perspective, 3PL was proposed and applied as a way to build on the streamlining of export of agricultural logistics system. The Agri 3PL is considered as an efficient agricultural exports method as a new concept connecting producers with exporters.

• Industrial Engineering and Management Systems
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• v.9 no.2
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• pp.97-106
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• 2010

Can eBay.com's fee structure coordinate the channel? It's a critical strategic problem in e-commerce operations and an interesting research hypothesis as well. eBay's fees include three parts: monthly subscription fee, insertion fee, and final value fee (i.e., a revenue sharing portion), which represent a generic form of revenue sharing fee structure between the retailer and the vendor in a supply chain. This research deals with such a channel consisting of a price-setting vendor who sells products through eBay's marketplace exclusively to the end customers. The up- and down-stream channel relationship is consignment-based revenue sharing. We use a game-theoretic approach with assumption of the retailer (i.e., eBay.com) being a Stackelberg-leader and the vendor being a follower. The Stackelberg-leader decides on the terms of revenue sharing contract (i.e., fee structure), and the follower (vendor) decides on how many units to sell and the items' selling price. This study formulates several profit-maximization models by considering the effects of the retail price on the demand function. Under such settings, we show that eBay's fee structure can improve the channel efficiency; yet it cannot coordinate the channel optimally.