• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.4
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• pp.601-611
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• 2010

Currently, a life cycle cost estimates(LCCE) is the most important factor in weapon system acquisition process. However, operation and maintenance(O&M) cost related studies are insufficient from the previous literature survey. O&M cost consists of various cost factors such a man power, maintenance and direct & indirect support costs. We have known that spare-parts cost is a key factor in the O&M cost. In this paper, we developed the spare-parts cost estimating relationships(CERs) of fixed-wing aircraft and armored vehicle weapon systems which include 4 historical cost drivers ; system acquisition cost, deterioration rate, localization rate, mission characteristic. Furthermore, we proposed the application methodologies that O&M cost estimating, total life cycle cost estimating and determination of the economic life using the spare-parts CERs.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1434-1439
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• 2011

The purpose of this study is based on the optimize the system life cycle cost apply to the advanced systems engineering techniques consideration thought to the system life cycle for the power system which is the one of the major component of the light rail transit system. Generally, the systems engineering techniques apply to the LRT's power systems are not optimize the whole life cycle cost of the power systems because systems engineering management activities are concentrate in performing the key-technology oriented at the construction stage of the dedicated power systems for light rail transit. Through this study, All the stakeholders can be utilize a this advanced systems engineering techniques which is fully considered the life cycle cost through the considering in whole system life cycle (such as concept, design, operation, maintenance and dispose stage as well as construction stage) and adopted by KSX ISO/IEC 15288 system life cycle processes.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.150-156
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• 1986

A Rankine cycle including heat exchange processes in the steam generator has been analyzed by the concept of available energy. The operation condition of the cycle can be expressed with the evaporation temperature, and there exists an optimum power condition at which the thermal efficiency of the cycle is almost the same as that of the Carnot cycle at the maximum power condition. The mass flow rate of the working fluid increases sharply as the evaporation temperature approaches to the critical point, and the regenerative system is needed to operate the cycle at the maximum power condition.

• Journal of the military operations research society of Korea
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• v.23 no.1
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• pp.138-150
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• 1997

The life-cycle of the K-1 tank has been 10 years simply applying that of the U.S. M-1 tank. Therefore, this paper is focused on determination of an economic life-cycle for the K-1 tanks. The current operation cost is adjusted by interest rate and the depreciation cost is applied in this study for more reliable estimation of the life-cycle cost. The Equivalent Annual Method is utilized and then various regression techniques are applied for deriving an effective economic life-cycle. The economic life-cycle of the K-1 tank results in 13 years in this study. considering 95% confidence interval, the life cycle of the K-1 tank is between 10.5 years and 15.5 years.

• Journal of Korean Institute of Industrial Engineers
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• v.37 no.4
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• pp.390-399
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• 2011

Generally the life-cycle cost of complex systems composed of several sub systems or equipments such as train, aircraft weapon systems is spent much more during operation and maintenance phase than development phase. The maintenance cost for maintaining the availability and extending the life span of systems comprise a large proportion of systems operation cost. The cycle of preventive maintenance affects operation and maintenance cost a lot. In this study we introduce a way minimizing life-cycle cost of systems by calculating more reliable preventive maintenance period than the results of previous study using systems reliability data considered the reliability and failure effect ratio of sub-systems or components. We can solve the preventive maintenance period problem known as NP-Hard as quick as possible by using modified genetic algorithm than using other models introduced in previous study.

• Journal of the Korean Society for Railway
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• v.13 no.3
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• pp.257-263
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• 2010

Operation and maintenance cost of a rolling stock is generally higher than its acquisition cost. Therefore, it is necessary for reducing life cycle cost (LCC) to make rolling stocks easy and low costly for operation and maintenance. In addition, their operation and maintenance support systems should be effective and efficient. To accomplish this, operator should specify LCC requirements in the early stage of acquisition and make a contractor to provide the rolling stocks of low LCC. This article presents a procedure and a verifiable LCC model available in the general acquisition process where an operator specify requirements and a contractor provide the rolling stock meeting the requirements.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.775-780
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• 2006

Mechanical and electrical performance of anode-supported SOFC single cells were analyzed after thermal cyclic operation. The experiments of thermal cyclic cell-operation were carried out four times and performance of each cell was measured at different temperatures of 650, 700, and $750^{\circ}C$, respectively. As increasing the number of thermal cycle test, single cells showed poor I-V characteristics and lower 4-point bending strength. The anode polarization was also measured by AC-impedance analysis. The observation of the microstructure of the anodes in single cells proved that the average particle size of Ni decreased and the porosity of anode increased. It is thought that the thermal cycle caused the degradation of performance of single cells by reducing the density of three-phase boundary region.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.816-818
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• 2016

The Industry 4.0 should decide work operation of manufacture facilities by itself. But small and medium sized enterprises(SMEs) still not prepared these work operations. In this paper, we had research that work operation manufacture facilities of a management system of mold life-cycle based on CPS. The management system of mold manages life-cycle using by shot, this information offers users by cloud system. This system will help SMEs products quality improve and business operation more efficiency.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1502-1513
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• 2006

This study analyzes the design and part load performance of a power generation system combining a micro gas turbine (MGT) and an organic Rankine cycle (ORC). Design performances of cycles adopting several different organic fluids are analyzed and compared with performance of the steam based cycle. All of the organic fluids recover greater MGT exhaust heat than the steam cycle (much lower stack temperature), but their bottoming cycle efficiencies are lower. R123 provides higher combined cycle efficiency than steam does. The efficiencies of the combined cycle with organic fluids are maximized when the turbine exhaust heat of the MGT is fully recovered at the MGT recuperator, whereas the efficiency of the combined cycle with steam shows an almost reverse trend. Since organic fluids have much higher density than steam, they allow more compact systems. The efficiency of the combined cycle, based on a MGT with 30 percent efficiency, can reach almost 40 percent. hlso, the part load operation of the combined system is analyzed. Two representative power control methods are considered and their performances are compared. The variable speed control of the MGT exhibits far better combined cycle part load efficiency than the fuel only control despite slightly lower bottoming cycle performance.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3236-3240
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• 2007

This paper describes the results of steam turbine performance tests. The objectives of performance test is to exactly evaluate the degradation(decrease in performance) of the coal-fired steam turbine generator in order to provide plant information to help performance engineers identify problems, improve performance, and make economic decisions about scheduling maintenance and optimizing operation. To achieve these goals, the periodic thermal performance tests have been carried out since the initial operation period, 1997. We made the calculation program and guidelines for the tests and developed the performance index of the turbine cycle on the basis of the ASME PTC. By comparing the performance changes throughout the whole operation period, we confirmed the performance reliabilities of the turbine and its conditions.