• Construction Engineering and Management
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• v.12 no.6
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• pp.36-48
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• 2011

도로건설프로젝트에서의 VE는 도로시설물의 기능을 향상시키고 비용을 절감하기 위한 방법으로 지금까지 널리 활용되고 있다. 그러나, 실제 건설VE 실무에서는 VE Job Plan 중 일부 단계가 생략되거나 형식적으로 수행되는 문제점이 발생되어 VE 수행결과에 대한 신뢰성에 의문이 제기되고 있다. 이는 제조업과 달리 대규모이며 복합공종을 갖는 건설프로젝트의 특성을 반영하지 못하고 있기 때문이다. 건설프로젝트는 대규모 복합공종으로 구성되어 복잡하고 다양한 기능 및 요구성능이 있으며, 시설물이 갖는 기능(Function)과 요구성능(Required Performance)의 일부는 반복적으로 발생하는 특징을 가지고 있다. 이에 본 연구에서는 VE Process의 실효성을 높이기 위하여 품질모델(Quality Model)과 기능분석(Function Analysis)단계에서 이러한 특징을 반영한 개선방향을 제시하고, 수차례 실무 검증을 통하여 적용성 및 효율성을 확인하였다. 이와 더불어 고속도로 VE Job Plan은 고속도로 설계 업무절차에 부합하도록 개선하여 VE 수행효과가 극대화 되도록 제안하였으며, 또한 한국도로공사에서 시행하는 고속도로 대한 VE절차를 "Hi-Value"라 명명하고 실무활용성, 효율성을 확대하고 지속적으로 발전시켜 나아갈 계획이다.

• Korean Journal of Optics and Photonics
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• v.13 no.3
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• pp.189-196
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• 2002

The components and alignment parameters of a flat-field soft x-ray spectrometer used in the wavelength range below 50 $\AA$ are determined, and the characteristics of the spectrometer are analyzed. It consists of a toroidal mirror, a slit, a varied line-spacing concave grating, and a soft x-ray detector. The space-resolved spectral image of a source is formed on a single plane using the tordidal mirror and the 2400-grooves/mm varied line-spacing concave grating. The former is used to compensate for the astigmatism caused by the grazing incidence of soft x-ray light on the concave grating. The spectral and spatial resolutions of the spectrometer are calculated by applying the wave front aberration theory, and the diffraction efficiency is calculated by applying the scalar diffraction theory.

• Korean Journal of Optics and Photonics
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• v.3 no.2
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• pp.77-85
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• 1992

The design of a flat-field XUV spectrograph is optimized for a high throughput, aberration-corrected spectral image in the wavelength region of 50-300 $\AA$ The varied-line spacing (VLS) concave grating theory for an XUV spectrograph with a toroidal mirror in front of an entrance slit is derived. Since the derived theory includes the arbitrary shaped source, it is able to correct the limit of the simple optimization theory which considers only a point source at the center of the entrance slit. The reflection matrix at the toroidal mirror and the diffraction matrix at VLS grating are derived and compared with those of a holographic grating. The absolute energy efficiency of a flat-field spectrograph is calculated by considering the reflectivities of the toroidal mirror and the Au coated concave grating and the grating efficiency. The alignment sensitivity of the toroidal mirror and the concave grating is investigated, and the method to achieve the best imaging of XUV spectrum is discussed. The calculated resolving power of the flat-field XUV spectrograph is more than 4000 in the aberration-corrected wavelength range. The focused spot size at the dispersion plane is less than $20\mu \textrm m\times \mu \textrm m$at the wavelength 100$\AA$ It is shown that a high throughput characteristic can also be achieved through a careful adjustment of alignment parameters.

• Journal of the KSME
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• v.33 no.8
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• pp.700-707
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• 1993

원자력발전소에 관한 사회전반의 관심고조와 함께 기술기준의 개발에 대한 필요성도 폭넓게 인 식된 결과 현재 발전사업자의 주도하에 정부 관련기관, 원전산업체, 하계 등이 공동으로 참여하여 "원전산업 기술기준 개발사업(2단계)이 수행되고 있다. 물론 기술기준의 개발은 매우 중요한 과 제임이 틀림없겠지만 개발된 기술기준을 어떻게 효율적으로 운영, 발전시켜 나가느냐가 더욱 중요한 과제인 바, 앞서의 검토에서 수차 강조되었듯이 미국을 비롯한 선진 원전국의 경우처럼 기술기준을 지속적으로 개발, 유지 및 보완하고 각종의 자격 인증에 관한 업무를 수행할 전담 기관을 정부, 발전사업자, 산업계, 학계 등의 적극적이고 자발적인 참여하에 하루 빨리 발족시 켜야만 산적한 현안문제를 해결하고 기술기준의 개정보완과 같은 계속성 업무를 체계적이고도 일관되게 수행할 수 있다고 판단된다.판단된다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.526_527
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• 2009

CBP(Cost-Based Pool) 시장에서 발전계획을 수립하고 시장가격을 산출할 목적으로 1999년 Alstom-ESCA(현 AREVA)사로부터 RSC(Resource Scheduling and Commitment, 이하 RSC)프로그램이 도입되었다. 그러나 단기간 발전경쟁시장 체제에서 사용할 목적으로 도입되었기 때문에 현재 CBP시장이 장기화가 예상되는 시점에서 전력시장 환경 및 구조변화의 흐름속에서 요구되는 기능을 제공할 수 있는 향상된 프로그램 도입의 필요성이 증가하게 되었고 이에 2008년 AREVA사로부터 한층 성능이 향상된 프로그램을 도입하게 되었고 올해 수차례의 모의운영을 통해 최적화 효율성 향상으로 발전비용이 감소되는 효과를 보여주고 있다. 본 논문에서는 이에 대한 모의운영 결과를 보여주고자 한다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.9
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• pp.1223-1227
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• 2013

If the factory test efficiency and field operation efficiency of water turbine are different from each other, issues for efficiency warranty can be raised. So, This paper shows the result for comparative analysis of field operating efficiency vs plant testing efficiency of the water turbine generator installed in agricultural reservoir. The efficiency of the induction generator is analyzed by the change of rotational speed with the parameter obtained by test, the efficiency of water turbine is calculated by the change of head with the design flow. Efficiency deviation of induction generator is lower but the variation of developed power is pretty high near the rated speed and the efficiency variation of water turbine is high by the fluctuation of head for constant flow. It was found that factory test efficiency and total efficiency of water turbine generator calculated according to the rotational speed are very close.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.205.2-205.2
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• 2011

Micro hydraulic turbines take a growing interest because of its small and simple structure as well as high possibility of applying to micro and small hydropower resources. The differential pressure exiting within the city water pipelines can be used efficiently to generate electricity like the energy generated through gravitational potential energy in dams. In order to reduce water pressure at the inlet of water cleaning centers, pressure reducing valves are used widely. Therefore, pressure energy is wasted. Instead of using the pressure reduction valve, a micro counter-rotating hydraulic turbine can be replaced to get energy caused by the large differential pressure found in the city water pipelines. In this study, in order to acquire design data of counter-rotating tubular type micro-turbine, output power, head, and efficiency characteristics due to the diffuser.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.205.1-205.1
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• 2011

This study concerns a low head and kaplan turbine efficiency measurement using the acoustic scintillation flow meter(ASFM). The ASFM is one of absolute discharge measurement methods because it measures velocity-area of discharge with couples of transducers. This study shows that the highest efficiency of turbine is 87.7% and the efficiency is 85.8% in the rated output(600kW). The test result is reliable because the efficiency trend from this test is similar to the result of index test conducted in 1986. In this paper, the principle, measurement methods, application and test procedures of the test are discussed.

• Korean Journal of Optics and Photonics
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• v.4 no.3
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• pp.289-293
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• 1993

A Nd:YLF laser pumped by a CW GaAlAs laser diode(LD) at 792 nm has been designed and fabricated. The output power was investigated as a function of LD spectrum and pump power. A folded laser resonator was desinged to compensate for the astigmatism produced at the Brewster surface of Nd:YLF rod. We obtained output power of CW 1.1 Watt when the pumping power was 2.8 Watt and the output wavelength of LD was temperature tuned to the peak absorption line of Nd:YLF. The overall efficiency was 39 % and slope efficiency was 41 %.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1018-1020
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• 2000

In the operation and maintenance activity of hydro turbine generator, one of the important parameters is the efficiency. This study analyze the case of efficiency management by pressure time method and survey the application of this method through the actual test. And it is confirmed that the Pressure time method exccesively limit the general condition to be applied. If index method is used for efficiency management because the index method calibrated by absolute discharge(by flow of pressure time method) is very accurate. it make to be able to manage the realtime efficiency.