• Journal of Labour Economics
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• v.33 no.2
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• pp.27-52
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• 2010

This study, using Korean Time Use Survey 1999, analyzes how opportunity costs of maternal time affects the ways in which mothers allocate their time to market work/housework/child care/leisure. Opportunity costs include two kinds: hourly child care costs and log hourly wage rates. Results show that a unit increase in child care costs reduces market work but increases housework, child care, and leisure. The effects of log wage rates are opposite those of child care costs. The result that a unit increase in the log wage rates decreases child care lime is not consistent with a previous study for the United Stales. These results differed by mother's educational attainments. This study suggests that policy-makers should pay careful attention to the effects of various types of mother's opportunity costs on non-market time in promoting maternal employment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.1
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• pp.67-72
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• 2004

This paper addresses the bidding strategies of generating firms in a competitive market where the firms are provided with payment for generating reactive power. Reactive support for voltage control is an integral and critical part of power system operations. Since reactive support is unbundled in a competitive market under open access transmission, it is treated as one of ancillary services. The operation costs and opportunity costs for reactive support are compensated by payment to the firms, hence their bidding strategies will be affected. The opportunity costs are evaluated from the foregone profits of a generator in making sales in real power market by providing reactive support instead of real power. Game theory approach is used to analysis the transaction strategies of real power by the bimatrix method in this paper. Through computing the Nash equilibrium in a sample system, an incentive of a generator for improving the reactive generating capacity is found to be effective and the variations of the profits are analyzed as the demand power factor changes.

• Journal of Families and Better Life
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• v.27 no.1
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• pp.31-44
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• 2009

The purpose of this study was to understand how consumers perceive the costs of using certain types of sales-promotions and to suggest ways in which sales-promotions should be developed to contribute to the consumers' welfare and the development of Marketing Strategy. The sufficiency of the consumers' desire was essential to new and creative sales-promotion strategy. This study investigated the perceived costs of using timely opportunity costs, extra expenses, substitution costs, uncomfortable feeling, regrets and economical and psychological satisfactions on certain types of sales-promotions such as off line, coupon, packed items, collection and on line, and event. In the study results on the perceived costs of using certain types of sales-promotions, off line sales-promotions were perceived more than substitution costs, extra expenses, regrets and on line sales-promotions were perceived more than timely opportunity costs. These results were caused by immediately using off line sales-promotions and becoming a member of on line sales-promotions. In the research result on the perceived costs of using certain types of sales-promotions and economical satisfactions, off line sales-promotions exhibited positive relations with substitution costs of coupon and extra expenses, regrets of packed items and collection about economical satisfactions. On line sales-promotions exhibited positive relations with extra expenses and regrets about economical satisfactions. The research results on the perceived costs of using certain types of sales-promotions and psychological satisfactions, off line sales-promotions exhibited positive relations with timely opportunity costs of coupon and collection about psychological satisfactions. On line sales-promotions exhibited positive relations with substitution costs about psychological satisfactions. These results were caused by the feeling of leisure time as the consumer played games or hobbies. This study proposes an approach in the context of sales-promotion with some suggestions and thoughts.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.75-86
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• 2010

The objective of this study is to suggest the process and method of local accident investigation for local authorities with a view to efficient and effective managing traffic accidents. With a project city selected accident-type maps, accident lists, accident diagrams, priority of black-spots/-lengths, site visits, remedial measures, opportunity costs, monitoring etc. are taken into consideration, by using accident data in the last 3 years. Analyzed are accident savings to be expected when applying technical, organizational, and administrative processes attached to local accident investigation.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.1
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• pp.18-26
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• 2014

Purpose: The purpose of this study was to estimate the cost of dental implant using the bottom-up approach with the current data from dental clinics. Materials and methods: In this study, direct and indirect costs required for each treatment were calculated using the bottom-up approach. In the bottom-up costing, the average monthly total cost of dental clinic includes labor and material costs, administrative expenses, medical malpractice costs, and opportunity costs of invested capital. For the dental implant cost components, those include direct costs (labor costs, laboratory costs, material costs, depreciation or other operating costs), indirect costs (administrative costs), and the opportunity costs of investment for dental clinic. Results: Dental implant costs of metal crown, porcelain crown and over-denture were 1,449,000 won, 1,583,000 won, and 2,471,000 won respectively. The proportion of cost components was as follows. The labor cost were 50%, and material, administrative and other cost were 33%, 15% and 2%, respectively. For direct, indirect and investment cost, the ratio were 83%, 15% and 2%, respectively. Conclusion: The labor costs were evaluated to comprise largest proportion (about 50%, 730,000 won). Dental implant cost using Bottom-up costing was 1,450,000 won for metal crown and 1,580,000 won for porcelain crown.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.30
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• pp.81-87
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• 1994

Productivity relates output to input and also integrates performance aspects of quality, efficiency and effectiveness. Productivity improvement are associated with efficiency and effectiveness, productivity index involved quality and flexibility, integrated productivity measurement system, and other factors. This study focused on the productivity improvement that involved the opportunity costs such as qualify costs and flexibility effects.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.65
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• pp.23-30
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• 2001

In this paper, we consider an inventory system in case the toleration to be inventory stortage under the price discount. It has been observed that suppliers suggest a free addition of marketing policy like a price discount. A major reason for a supplier to offering a free addition to a customers is to stimulate the demand and to decrease a total cost. but, If we not adapting to the toleration to be inventory-lacking, we will a burden holding costs in a relation to the holding of inventory. This paper, is a combination of the toleration of inventory shortage and the condition of discount price. The costs are defined as the sum of the ordering, holding, shortage, purchasing and opportunity costs. Based on numerical results, conclusions follow about the total of operation costs the division of the shortage rate of inventory.

• Korean Journal of Social Welfare
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• v.61 no.2
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• pp.371-389
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• 2009

This study estimates the socioeconomic costs of missing children in Korea. The costs were classified as direct costs and indirect costs. The direct costs consisted of direct costs for searching for missing child such as making posters, transportation, and medical costs. The indirect costs were computed by the opportunity costs caused by child missing. The total costs that could be attributable to missing child were estimated to be about 570 million won per long-term missing child. This provides strong evidence that prevention of child missing is the most important and quick recovery after child is missing is the second most important. Missing child incurs substantial socioeconomic costs to the Korean society. Therefore, this study provides strong need for more interest from people who are indifferent to missing child issues and strong support for more government interventions to solve missing child problem in Korea. Further studies are needed to calculate socioeconomic costs of child missing more exactly.

• Proceedings of the KOR-KST Conference
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• 2007.11a
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• pp.287-295
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• 2007

• Journal of Korea Port Economic Association
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• v.22 no.4
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• pp.59-79
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• 2006

In this paper, we analyse the comparative competitiveness of the 10 major logistic hub cities in China. First, using the input distance function, we calculated the technical efficiencies and the opportunity costs of the transport infra structure investments. Then, based on not only these supply side factors but also demand side, the overall comparative competitiveness by cities are analyzed. Our main findings are as follows: early developed, larger cities such as Shanghai, Guangzhou, Shenzhen are technically efficient but their opportunity costs of the additional transport investments are higher than the other cities. We also found that overall competitiveness of these larger and leading logistic hub cities are dominant over the small and newly developed logistic cities.