• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.3
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• pp.105-117
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• 2001

This paper models supply uncertainty in the dynamic Newsboy problem context. The system consists of one supplier and one retailer who places an order to the supplier every period to meet stochastic demand. Supply uncertainty is modeled as the uncertainty in quantities delivered by the supplier. That is, the supplier delivers exactly the amount ordered by the retailer with probability of $\beta$ and the amount minus K with probability of (1-$\beta$). We formulate the problem as a dynamic programming problem and prove that retailer’s optimal replenishment policy is a stationary base-stock policy. Through a numerical study, we found that the cost increase due to supply uncertainty is significant and that the costs increase more rapidly as supply uncertainty increases. We also identified the effects of various system parameters. One of the interesting results is that as retailer’s demand uncertainty, the other uncertainty in our model, increases, the cost increase due to supply uncertainty becomes less significant.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.300-306
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• 2020

This study analyzes the distributor's inventory model in a two-stage supply chain consisting of the supplier, the distributor and the end customer. The supplier will allow a credit period before the distributor settles the account with him in order to stimulate the demand for the product he produces. It is also assumed that the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. As a result, the availability of a credit transaction leads to an increase in inventory levels. On the other hand, in the case of deteriorating products in which the utility of the product perish over time, the deterioration rate with time plays a role in reducing inventory levels. In this regard, we analyze the effect of the length of the credit period and the degree of product deterioration on the distributor's inventory level. For the analysis, we formulate the distributor's annual net profit and analyze the effect of the length of credit period and deterioration rate of the product on inventory policy numerically.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.4
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• pp.13-30
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• 2008

We explore the determinants of long-term relationship between the buyer and the supplier to help suppliers develope a strategy to build long-term relationship with their buyers. Based upon an extensive literature review, we propose three droops of independent variables which may affect long-term relationship, including (a) environmental factors (product complexity, product importance, source dependence, price sensitivity), (b) relational factors(trust, commitment, satisfaction, intention of expansion), (c) operational performance(quality, delivery, cost capability, technical knowhow). The buyer's actual period of relationship with its main supplier is used as a dependent variable. Using hierarchical multiple regression analysis, we empirically test hypotheses, analysing a sample of 290 manufacturing firms in the U.S. The statistical results indicate that the buyer's source dependence, price sensitivity and the supplier's commitment play a significant role in establishing long-term relationship between the buyer and the supplier. However, the supplier's cost capability and technical knowhow in operational performance negatively affect long-term relationship in contrast with our hypotheses. Due to this controversial result, we divide the sample group Into dual sourcing and multiple sourcing environments and reconduct regression analysis in a post hoc manner. The findings show that the supplier's cost capability and technical knowhow are negatively associated with the length of relationship only in the multiple sourcing environment. The results may confirm that both parties' opportunistic behavior is more salient in the multiple sourcing environment than in the single sourcing environment.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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• pp.63-78
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• 2004

This paper deals with a supplier-managed inventory(SMI) control for a two-echelon supply chain model with a service facility and a single supplier. The service facility is allocated to customers and provides a service using items of inventory that are purchased from the supplier, Assuming that the supplier knows the information of customer queue length as well as inventory position in the service facility at the time when it makes a replenishment decision, we identify an optimal replenishment policy which minimizes the total supply chain costs by reflecting these information into the replenishment decision. Numerical analysis demonstrates that the SMI strategy can be more cost-effective when the information of both customer queue length and inventory position is shared than when the information of inventory position only is shared.

• Journal of Information Technology and Architecture
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• v.9 no.4
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• pp.365-376
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• 2012

We examine the value of information sharing in the context of supplier-buyer relationships after controlling for trading partners' opportunism. Given that trading partners' opportunism is not randomly chosen, we explicitly incorporate their self-selection process into our estimation procedure by employing Heckman's self-selection model. According to our analysis, firms that have built safeguards via mutual trust, commitments and information sharing experience less opportunistic risk in supplier-buyer relationships. Our findings also suggest that information sharing has a positive impact on firm performance after controlling for opportunism. Further, firms that are less exposed to trading partners' opportunistic risk have achieved a higher performance than others that are more exposed. Importantly, higher performance for those firms with less opportunistic risk is driven by safeguards in supplier-buyer relationships as well as information sharing. Our findings can be applied for systems analysts to design information systems of supplier-buyer transactions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.10a
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• pp.99-102
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• 2000

In the supply chain network design, how to select the best location, capacity configuration of the suppliers and to assign manufacturers orders are a challenging issue. Especially when multi-tiers'suppliers are existed, the performance of supply chain is influenced by 2$\^$nd/ and 3$\^$rd/ suppliers. Supplier selection is multi-criteria problem which includes both qualitative and quantitative factors in supply chains. In order to select the best supplier it is necessary to make a trade off between these two factors such as cost, product quality, capacity, production lead time, deliver lead time and transportation lead tine of supplier constraints existed in multi-tiers supplier purchasing chain. In these circumstances, purchasing agents should decide two problems: which is the best supplier in each tier and how much should be purchased from each selected supplier. This research is intended to develop an integration of an analytical hierarchy process (AHP) and mathematical modeling proposed to consider two factors which may be conflicted in choosing the best supplier in each tier and placing the optimum order quantities to the supplier among multi-tiers suppliers.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.2
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• pp.213-221
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• 2019

The study aims to investigate some criteria of supplier selection in the textile and apparel (T&A) sector in Vietnam. Most research on supplier selection criteria for T&A sector was mainly conducted based on the review of literature. Therefore, the purpose of this study is to explore these criteria based on a framework in which an integrated approach of qualitative and quantitative was employed. First, an in-depth interview was used to explore what supplier selection criteria T&A companies were utilized after the literature on supplier selection criteria had been reviewed. Next, a prequestionnaire was built and sent to some practitioners and experts for their revision. Then, a pilot survey of 31 T&A companies with numerous statistical tests was conducted to validate the questionnaire. Finally, an official study of 282 respondents was conducted to determine supplier selection criteria which are best suited for T&A companies through exploratory factor analysis. The findings of the study suggest that there are eight supplier selection criteria including Quality, Cost, Delivery, Service, Capability, Company's image, Relationship, and Sourcing country. Each criterion comprises certain sub-criteria to make the supplier selection criteria set more comprehensive. The findings will be a contribution to the selection process of T&A companies as they can utilize these criteria to select capable suppliers.

• Journal of the Korean Operations Research and Management Science Society
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• v.40 no.3
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• pp.1-21
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• 2015

Customer firms exercise various sources of power to influence their suppliers' behaviors or decisions. In this study we aim to examine the effects of customers' sources of power on their supplier's performance improvement. This study posits that a customer's expert, referent, and reward power positively influence a supplier's performance directly as well as indirectly through increased supplier-customer integration. On the contrary, the customer's coercive power is expected to worsen the supplier's operational performance because of increasing distrust, dissatisfaction, and conflict with the customer. Data collected from 1,229 firms from Korea, China, Hong Kong, Taiwan, and the U.S. are used to test the hypotheses. Expert power proves to be the most effective source of customer power in improving a supplier's inventory cost, delivery, and flexibility performance. In contrast, coercive power deteriorates significantly all supplier performance variables. Academic and managerial implications are presented and future research directions are also discussed.

• Journal of Korean Institute of Industrial Engineers
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• v.32 no.4
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• pp.382-392
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• 2006

Vendor-managed inventory policy(VMIP) is a supply-chain initiative where the supplier is authorized to manage inventories of items at retail locations. In VMIP, the supplier monitors sales and stock information at retail locations and makes decisions of inventory replenishment and transportation simultaneously. VMIP has been known as an effective supply chain strategy that can realize many of benefits obtainable only in a fully integrated supply chain. However, VMIP does not always lead to lower the supply chain cost. It sometimes generates the total supply chain cost higher than the traditional retailer-managed inventory policy (RMIP). In this paper, we perform a comparison study on RMIP and VMIP in the retail supply chain which consists of a single supplier and a number of retailers. We formulate mixed integer programming models for both RMIP and VMIP with vehicle routing problems and perform computational experiments on various test problems. Furthermore, we derive the conditions which guarantee the dominant position for VMIP with respect to total supply chain cost in the simple retail supply chain.

• Industrial Engineering and Management Systems
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• v.8 no.4
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• pp.228-238
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• 2009

This paper first presents two supply chain design problems: 1) a factory location setting and factory selection problem, and 2) a factory location setting and factory/supplier selection problem. The first involves a number of location known retailers choosing one factory to supply their demands from a number of factories whose locations are to be determined. The goal is to minimize the transportation and manufacturing cost to satisfy the demands. The problem is then augmented into the second problem, where the procurement cost of the raw materials from a chosen material supplier (from a number of suppliers) is considered for each factory. Economic beneficial is taken into account in the cost evaluation. Therefore, the partner selections will influence the cost of the supply chain significantly. To solve these problems, an agent gaming and genetic algorithm hybrid method (AGGAHM) is proposed. The AGGAHM consecutively and alternatively enable and disable the advancement of agent gaming and the evolution of genetic computation. Computation results on solving a number of examples by the AGGAHM were compared with those from methods of a general genetic algorithm and a mutual frozen genetic algorithm. Results showed that the AGGAHM outperforms the methods solely using genetic algorithms. In addition, various parameter settings are tested and discussed to facilitate the supply chain designs.