• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.4
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• pp.49-62
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• 1999

Since the Internet was applied for commercial purpose, many companies have been making use of the Internet in electronic commerce and the Internet has brought many changes on consumer and supplier behaviors. It seems that consumers and suppliers can obtain more accurate information rapidly and pay less for the same product/service than in traditional commerce. This study tries to investigate the difference in the cost factors perceived by consumers between traditional commerce and the Internet commerce. Empirical results show that there is no significant difference in consumers' perception of cost factors between traditional commerce and the Internet commerce. Contrary to general perception, a large number of consumers do not believe that the Internet commerce is generally more economical than traditional commerce. The factors where the consumers think Internet commerce has cost advantages are search cost and purchasing cost. However, consumers are understanding the benefits of the Internet commerce and are expecting that Internet commerce bring about economic advantages in consumer markets in the near future.

• Journal of the Korean Operations Research and Management Science Society
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• v.35 no.4
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• pp.33-53
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• 2010

When purchase prices of a raw material fluctuate over time, the total purchasing cost is mainly affected by reordering time. Existing researches focus on deciding the right time when the demand for each period is replenished at the lowest cost. However, the decision is based on expected future prices which usually turn out to include some error. This discrepancy between expected prices and actual prices deteriorates the performance of inventory models dealing with fluctuating purchase prices. In this paper, we propose a new inventory model which incorporates not only cost but also risk into making up a replenishment schedule to meet each period's demand. For each replenishment schedule, the risk is defined to be the variance of its total cost. By introducing the risk into the objective function, the variability of the total cost can be mitigated, and eventually more stable replenishment schedule will be obtained. According to experimental results from crude oil inventory management, the proposed model showed better performance over other models in respect of variability and cost.

• Journal of the Korean Dietetic Association
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• v.7 no.1
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• pp.80-86
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• 2001

The purposes of this study were to: a) examine characteristics of foodservice management practices; b) investigate characteristics of recipients; c) analyze foodservice systems; and d) provide feedback for the efficient and effective foodservice management of mental disorder care sites in Korea. A total of 46 sites was analyzed by questionnaire survey. Statistical data analysis was completed using the SPSS package program for descriptive analysis. As results of site recipients' characteristics, 60% of total sites were males and 40% were female recipients. Average 60% of recipients were from 30 to 40 years old. Major diseases of recipients were mental disorder, high pressure, and obesity. According to the result of foodservice system analysis, the average meal cost per day was about 2,921 won and average food cost percentage was 39%. Average number of meals per day was about 600 meals. All sites had on dietitian and 88.3% of sites had one cook as a full-time employees. In the part of procurement, dietitians were major chargers of sites for purchasing foods. Major purchasing method was the order and delivery contract. About a half of sites used cycle menu system and standardized recipies. Most of sites had recipients survey systems for evaluating meal satisfaction. About 60% of sites provided liquid diets to recepients and 22% provided diabetic diets. Dietitians at sites had problems on low meal cost budget, lack of cooking professionals, and lack of information about treatment meals for mental disorders for providing higher quality of foods cure recipients. The results suggested that financial and systematical supports by the government would be very necessary to meet the goal of nutritional balanced meal services.

• Korean Management Science Review
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• v.21 no.3
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• pp.1-12
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• 2004

The paper demonstrates that versioning of digital products occurs more frequently than that of physical products because of low marginal cost. The versioning occurs no matter what a customer knows his/her reservation price. Low-quality version will not be produced when the difference between reservation prices is very large. The paper also shows that a firm tries to lower the quality of low-quality product to prevent customers with high reservation prices from purchasing low-quality product.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.173-183
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• 1995

Life cycle cost has been one of the key criteria in design or purchasing of systems, particularly in the flying weapon system. Unexpected cost increase or system breakdown during the system life can be reduced by controlling maintenance cost A system should be designed for maintainability in early stage of product life cycle. The design should be insensitive to its environmental, organizational, and human factors in the stage of customer's utilization. This paper presents LCC as a controllable variable and also suggests a new control model for LCC analysis. The estimation of maintenance cost based upon maintenance scenario, design of maintainability followed by minimizing maintainability loss function in the beginning stage of design, and increase of useful life of systems are among the factors to control LCC.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.93-101
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• 2009

The use of the gas turbine for power supply is increasing recently. Accordingly, the operation and maintenance cost of the gas turbine is gradually increasing and the various efforts to cut the cost are needed. For an operation and maintenance cost saving of the gas turbine, reductions of the new purchasing charge and the reproduction repair cost of the hot gas parts are required through more effective operation and life management methods for the hot gas parts. The hot gas parts are the main parts of the gas turbine and they are replaced with the periodic. In this research, efficient operation and life management methods for the hot gas parts were presented with the cases. The methods were analyzed and verified based on real data and the cases for improving a lifetime were utilized in the field.

• Journal of the Korea Safety Management & Science
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• v.9 no.4
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• pp.121-127
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• 2007

CSP(Concurrent Spare Parts) is supplied with the procurement of new equipment or weapon system and is used to sustain the equipment without resupply during the initial coverage period. This study is concerned with a problem of determining the near optimal inventory level of the spare parts, especially Concurrent Spare Parts. For this, we utilize the mixed periodic and continuous review polices considering the CSP and (r,Q) Policies concurrently in a two-echelon distribution system. We propose the mathematical model to minimize the total cost which is composed with ordering cost, purchasing cost, holding cost, and stickout cost. If the mixed policy is compared to other policies(CSP, (r,Q)), the proposed methodology performs well and is best policy in the equipment maintenance expenses.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.197-199
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• 2014

Todays, with the spread of Mobile devices, SNS service usage has been increasing. While SNS services have many benefits such as providing communication with social functions, these have also negative aspects like fatique. In the point that consumers make their own purchasing decision with considering cost and benefits of goods and services, this paper is to evaluate the value of SNS services considering both sides of beneficial and cost aspects.

• International Journal of Railway
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• v.9 no.1
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• pp.10-14
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• 2016

Life cycle cost analysis is compulsively required for the system operation. System operation costs are consisted of acquisition, operation, maintenance and so on. In the beginning of the system planning, we need to take into account of various costs following the system operating. To implement LCC, we need to analyze system life cycle to identify all costs during system life. The costs can be divided into three parts. The first part is purchasing cost, the second for operating cost and the last for disposal cost. The second operating cost can be decomposed of operating cost included labor, energy consumption cost for system running, maintenance costs to keep systems healthy, delay cost caused from maintenance and hazard cost, and so on. In this paper, we carried out for railway locomotives which operate over more 30years and which cost about 10 million USD. We decompose the life cycle of the locomotives and break down the locomotives into subsystems to require maintenance or not, and subsystems to need energy or not. We showed how to decide optimal locomotives through cost identification and system breakdown.

• Journal of the military operations research society of Korea
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• v.28 no.2
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• pp.85-94
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• 2002

Calculation of proper expenses on acquisition and purchasing defense product is matter of survival and weighing the morality for both defense industry and the national facilities. With this reason, both parties have been a big job to estimate the resonable cost. The cost are composed of many subordinated parts such as material cost, labor cost, and so on. In the compositions of that cost, the most important part in between companies and the government throughout the whole calculating process is to define the proper labor cost. When both parties calculate imported articles or overhead expenses, they can easily calculate and confirm by documented evidences or related materials. In other hand, the labor cost, which can be seen as two absolutely different numbers and opinions can be created, depends on analyzer's point of view. These interpretation and judgment of data cannot avoid analyzer's intention. In accordance with the above matters, defining the reasonable labor cost will be the top priority in order to analyze the proper expenses. This study will provide a method of proper labor cost estimation before starting the actual manufacturing to calculate the rational labor cost.