• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2223-2224
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• 2006

전기에너지는 저장성이 없기 때문에 부하의 불규칙적인 변화에 대한 실시간 대처가 어렵다. 그 중 전력계통의 대규모 공급지장에 대비하여 안정적인 공급을 위해서 예비력은 중요한 요소이다. 예비력이 필요 없다면 경쟁적 입찰을 통해 최적의 가격설정을 할 수 있겠지만 예비력은 계통의 안정적 운영을 위해 반드시 필요하다. 예비력을 운영함으로써 경제적 손실이 발생하는데 이를 최소화하기 위한 일환으로 예비력 운영에 대한 적절한 가격결정이 필요하다. 본 논문에서는 예비력시장을 운영함으로써 발생하는 기회비용을 고려하여 에너지와 예비력 가격 설정방법을 제시하였다.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1257-1258
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• 2006

전기에너지는 저장성이 없기 때문에 부하의 불규칙적인 변화에 대한 실시간 대처가 어렵다. 그 중 전력계통의 대규모 공급지장에 대비하여 안정적인 공급을 위해서 예비력은 중요한 요소이다. 예비력이 필요 없다면 경쟁적 입찰을 통해 최적의 가격선정을 할 수 있겠지만 예비력은 계통의 안정적 운영을 위해 반드시 필요하다. 예비력을 운영함으로써 경제적 손실이 발생하는데 이를 최소화하기 위한 일환으로 예비력 운영에 대한 적절한 가격결정이 필요하다. 본 논문에서는 예비력시장을 운영함으로써 발생하는 기회비용을 고려하여 에너지와 예비력 가격 설정방법을 제시하였다.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1717-1718
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• 2006

전기에너지는 저장성이 없기 때문에 부하의 불규칙적인 변화에 대한 실시간 대처가 어렵다. 그 중 전력계통의 대규모 공급지장에 대비하여 안정적인 공급을 위해서 예비력은 중요한 요소이다. 예비력이 필요 없다면 경쟁적 입찰을 통해 최적의 가격설정을 할 수 있겠지만 예비력은 계통의 안정적 운영을 위해 반드시 필요하다. 예비력을 운영함으로써 경제적 손실이 발생하는데 이를 최소화하기 위한 일환으로 예비력 운영에 대한 적절한 가격결정이 필요하다. 본 논문에서는 예비력시장을 운영함으로써 발생하는 기회비용을 고려하여 에너지와 예비력 가격 설정방법을 제시하였다.

• Journal of Aerospace System Engineering
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• v.17 no.5
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• pp.1-10
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• 2023

This research sought to determine the optimal cycle of Planned Depot Maintenance (PDM) for Unmanned Aerial Vehicle (UAV), and PDM through Reliability and Maintainability-based simulation and Operating and Support (O&S) cost analysis using Reliability and Maintainability analysis results. The effectiveness of the PDM was verified economically, and the optimal PDM interval that balances UAV effective operations and sustaining engineering costs was presented.

• Journal of the military operations research society of Korea
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• v.35 no.3
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• pp.31-45
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• 2009

Reliability should be done from the initial stage of development to secure performance and safety of system. To establish and achieve target reliability of a system, reliability should be allocated into the subsystems. In the acquisition and development of a system, frequent failures will cause a negative effect on performing mission and occurs increasing operating cost. This study reviewed and evaluated the existing reliability allocation models using operation and maintenance costs to find the correlation between reliability allocation models and its operating cost. A target system reliability on the diesel engine to be developed for naval vessels is allocated into its subsystem based on the existing reliability allocation models. A selection methodology for reliability allocation models was made to minimize operating cost by using simulation based on the given operating diesel engine data for naval vessels.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1395-1411
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• 2009

The Korea railroad industry has experienced the operating deficit annually since 1980. And the ridership has been reduced since 1990. Therefore, a structural reform of the Korea railroad industry conducted at 2003. Basic principles of their structural reform are no differences among the Korea and advanced counties. But different outcomes depending on each country situation appears. These cost functions appear the existence of all economic of scale. And when increase the average transport distance annually, the average cost reduce annually. The results of structural reform by comparing before and after, the average cost was lower than previously. The Structural reform and the operation of the KTX, the two effects at the same time, the synergy effect has occurred. Because of the synergy effect, the performance is estimated to be larger. Due to the effective operation of structural reform that could reduce costs.

• Journal of Korean Society of Transportation
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• v.26 no.6
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• pp.113-122
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• 2008

This study extended Park et al.(2007c), which analyzed the efficiency of a hierarchical transit network, showed the result of a real data, and analyzed its applicability. Operating cost was estimated using a model which was established in this study, and minimum transit demand was derived from the operating cost. The minimum transit demand value is just a sample calculation, thus it varies by many inside and outside factors of the model. Looking at the inside of the model, operating cost and travel speed are major factors, and the possibility of introducing urban subway becomes high when the operating cost of the transit system is low and its travel speed is high. As far as the outside factors are concerned, according to the analysis on the network structure, transit demand, and transit mode share, the minimum transit demand value which was derived in this study will be the maximum value among the possible values. In the feasibility study, the benefit is likely to be overestimated and the cost is likely to be underestimated than those of this study. It could be concluded that the methodology of a feasibility study is appropriate in the field standard. This study analyzed the efficiency of introduction of urban subway using analytical approach, thus has many shortcomings and limitations. However the practical approach, like feasibility study, has some limitations as well. This study could be a basis on establishing an analysis framework that is more accurate and reasonable by comparing analytical approach and practical approach.

• Korean Journal of Construction Engineering and Management
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• v.7 no.6
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• pp.185-192
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• 2006

The maintenance expenses of public rental housing have drastically been increased as facilities become obsolete. As an effective means of managing such a situation, accurate estimating of maintenance expenses and securing financial resources are crucially important. It, therefore, is necessary to analyze major factors affecting on maintenance expenses of public rental housing's facilities, and develop an effective instrument to estimate them. On the other hand, the U.S.A, where approximately 60 percent of public rental housing's operating costs are supported by the state, has already developed an effective tool to forecast operating costs based on several years' actual data. As a result, public rental housing has been operating with a reasonable level. However, there have been no remarkable researches and studies in this field in Korea. In this context, this study attempts to examine principal determinants of maintenance expenses of public rental housing's facilities, and their influence based on the latest five years' actual operating costs. This study may contribute to develop an objective and precise tool to forecast maintenance expenses of public rental housing.

• Resources Recycling
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• v.23 no.3
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• pp.3-12
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• 2014

This study aims at providing an economic assessment for incineration plants which recover heat during its incineration process. In this study, Life Cycle Cost(LCC) of incineration plants is performed based on each regression analysis formula for construction cost, operation cost, and heat generation in order to compare economic feasibility. The result shows that the incineration plant recovering waste heat while processing 80 tons of waste per day increases both initial investment and operation cost but this type of an incineration plant has economical predominance from the recovered waste heat over the one that does not recover heat when being operated for more than eleven years if the retrieved heat replaces the use of LNG. And its payback time reaches more than 19 years in case of selling heat and performing emission trading.

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.163-173
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• 2015

In this paper, it shows optimal inventory level of bicycle sharing service terminal by maintaining the lowest costs. As the interest to environment and exhaustion of resource increases globally, investment to sustainable transportation increases around advanced countries and interest to efficient transportation, managing and consuming of vehicle increases also. Vehicle sharing service is a model of rental car where customer rent cars for short periods of time often by the hour and its users are increasing for the reason that it is more convenient than car rent. In addition, bicycle sharing service is one of the major parts in vehicle sharing program and many of country are already managing it. This paper proposes optimal inventory levels of vehicle sharing service's terminal by using simulation calculating operation costs of vehicle sharing service.