• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.88-93
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• 2008

This paper proposes a frequency transfer function synthesis of a later compensated PID controller for an approximated low order model. The proposed method identifies the parameter vector of PID controller from a linear system that is formed by rearranging a loop frequency transfer function synthesis including the filter compensated PID controller obtained from the given frequency response bounds. And an example for the turbine speed control system of Chungju hydropower plant is given to illustrate the feasibilities of suggested schemes.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.495-498
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• 2006

The Kaplan turbine model has been tested and analyzed. The blade angle and the guide vane opening of the turbine model were designed to be varied according to the best combination of guide vane and runner blade opening. When the changes in head and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed model in this study will be suitable for small hydropower stations with large changes In head and load such as agricultural reservoir.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.643-650
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• 1997

경제성장과 생활향상에 따라 증가일로에 있는 전력에너지를 효율적으로 공급하기 위해서는 원자력발전소의 증설이 불가피하다고 판단하여 정부는 이에 대한 중장기계획을 수립하여 추진하고 있다. 아울러 원전에서 발생하는 방사성폐기물을 처분할 시설의 입지를 위해서도 수차에 걸쳐 노력을 하여왔다. 그러나, 1970년대에 건설이 이미 완료되었거나 건설을 착수한 것 외에는 원자력시설의 입지에 지금까지 성공한 것이 없다. 입지실패의 원인 중 하나는 그간 입지정책을 추진해 오는 과정에서 입지 접근방식에 대한 검토가 부족하여 입지전략이 제대로 수립되지 않았던 때문인 것으로 사료된다. 본 연구는 원자력시설을 입지시키기 위해 널리 활용되어 온 시설입지 접근방식들을 구체적으로 고찰하여 시설입지에 대한 반발현상을 체계적으로 이해함으로써 원자력시설의 성공적인 입지에 첩경이 되고자 하는데 그 목적이 있다. 연구 결과, 성공적인 시설입지를 위해서는 어느 하나의 특정 접근방식에만 주안점을 둔 전략 모색은 결코 바람직하지 못하고 입지추진단계와 절차 및 대상 등에 따라 세 가지 접근방식을 적절하게 활용하는 전략을 모색하여야만 시설입지에 대한 반발을 효과적으로 극복하고 시설을 성공적으로 입지시킬 수 있을 것으로 판단된다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.357-360
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• 2022

우리나라는 1997년 IMF 경제위기 이후 기업의 지배구조와 관련한 상법과 증권거래법 등이 수차례에 걸쳐 개정을 통한 정비가 되었다. 기업지배구조에 대한 문제는 우리나라 경우에만 한정되는 것이 아니라 미국을 비롯한 유럽 등 많은 선진국에서 중요한 문제점으로 대두되고 있는 것이 사실이다. 특히 우리나라에서 기업지배구조와 관련하여 많은 문제가 발생되고 있는 것은 지배주주와 경영진의 기업경영에 대한 감독 등이 제대로 이루어지지 않았을 뿐만 아니라 지배주주와 기업 경영진들에게 그에 책임을 제대로 묻지 않았기 때문이다. 그리고 아직도 우리나라 대부분의 기업들에 있어서 오너 경영자의 소유주식 비중이 높은 관계로 의사결정권을 독선적으로 행사하는 등 사실상 경영의 건전성을 확보할 수 없었던 것이다. 따라서 본 연구에서는 이사회가 본연의 기능을 회복하고 바람직한 지배구조를 개선하는데 있어서 걸림돌이 되는 부분을 검토하고 그에 대한 효율적인 개선안을 제시하고자 함이 연구의 목적이다.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.241-249
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• 2017

This paper presents the design and evaluation of the optical system for an uncooled thermal-imaging camera. The operating wavelength range of this system is from $7.7{\mu}m$ to $12.8{\mu}m$. Through optimization, we have obtained a LWIR (Long Wave Infrared) optical system with a focal length of 5.44 mm, which consists of four aspheric surfaces and two diffractive surfaces. The f-number of the optical system is F/1.2, and its field of view is $90^{\circ}{\times}67.5^{\circ}$. The hybrid lens was used to balance the higher-order aberrations, and its diffraction properties were evaluated by scalar diffraction theory. We calculated the polychromatic integrated diffraction efficiency, and the MTF drop generated by background noise. We have evaluated the thermal compensation of a LWIR fixed optical system, which is optically passively athermalized to maintain MTF performance in the focal depth. In conclusion, these design results are useful for an uncooled thermal-imaging camera.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.1
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• pp.1-12
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• 2023

Along with the growing interest in renewable energy development, Korea's west coast is one of the favorable regions for tidal power. Tidal power using tidal barrages that work like hydroelectric dams is a representative method of tidal power through long-term operation, but the promotion of tidal power projects is being delayed or stopped due to impacts on ecological changes, reproduction, water column processes and hydrology. In order to reduce the high construction cost and environmental cost problems caused by tidal power using tidal barrages, in this study, field experiments were conducted to develop and verify the performance of tidal power generation devices applicable to sea areas where dykes are already installed. As a result of conducting five cases of experiments using two water tanks, pipe lines, open channels, and water turbine and generator, the possibility of developing a power generation system capable of generating more than 10 kW output and more than 60% efficiency were confirmed. The results of this study can be used for small-scale tidal power by utilizing the existing dykes of the west coast.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.1
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• pp.13-21
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• 2023

As problems such as difficulties in securing stable energy resources and global warming due to the emission of greenhouse gases due to the use of fossil fuels have emerged, interest in the development of renewable energy is increasing. Since the tidal phenomenon has a regularity that occurs regularly with a certain period, it is possible to predict accurately in advance, which has a advantage in terms of energy recovery. Therefore, various methods have been devised to utilize the tide as an energy source. Tidal power using barrages is a representative method that is widely operated, but the promotion of tidal power generation projects is being delayed or stopped due to the decrease in the level of water in the tidal basin, changes in water quality and in the ecosystem. In this study, a field experiment was conducted to develop and verify the performance of a tidal power device applicable to sea areas where dykes are already installed. As a result of carrying out four cases of experiments using two water tanks, pipe lines, open channels, weirs, and water turbine and generator, the possibility of developing a power generation system capable of 10 kW output or more and 60% efficiency or more was confirmed. These research results can be used for small-scale tidal power by utilizing the existing dykes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.14 no.1
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• pp.39-47
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• 1996

This paper is to provide land cover classification techniques for large area ranged in different pathos by classifying Landsat TM data of Jeonnam province. The analyses proceeded by individual scene because acquired dates are not same in different pathes. In this processing, troubles had happened something like variation of classes can be classified in two scenes and choice problem about overlapped area. Since spatial effects in large area affect data values, it was difficult to make a selection of classes and training fields. we could present a solution about these problems by trial and error method, and found that Bayesian maximum likelihood classification and majority filtering were effective to improve classification accuracy.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.49-52
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• 2006

should be in English, A make out an economical, reliable and easy to adoptable instrument in turbine discharge measurement was restricted from lots of it's foundational condition. Not with standing the brilliant progress in new technology of these day, useful instrument for flow measurement in turbine is still ongoing. Nowaday, the increasing importance of renewable energy makes it more important that the measuring turbine efficiency as a decision making index of old turbines' replacement. In Turbine performance diagnosis, Kwater(Korea Water Corporation) got an enough ability and decent reputation for who has invested lots of time and effort for buildup and development. In Korea as a public corporation who should take a crucial roll in Turbine business, Kwater has introduced some developed new technology for other domestic concerned one. With this writing, I'd like to introduce ASFM system as a newly developed instrument that can cope with lots restriction in discharge measurement in turbine. Kwater adopted the system in 2005, and performed 2 times of trial test. The test result was good enough to use the system as a reference test method.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.120-127
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• 1999

We discussed two main types-conformal and non-conformal (powered) - of holographic combiner. A theoretical model based on the Kogelnik's coupled wave theory was used to illustrate bandwidth and efficiency properties. Also we showed numerical values for the aberrations that are induced by a wavelength shift from construction to reconstruction and found optimum coordinates to reduce the chrolatic aberation of construction beams using aberration balancing techniques. The holographic combiner manufactured in conformal type with 60$^{\circ}$ incidence angle at 514.5 nm had narrow angular bandwidth (FWHM) of 4.1" and spectral bandwidth of 11.4 nm, while non-conformal one with 50$^{\circ}$, 30$^{\circ}$ incidence angle at 514.5 nm showed spectral and angular bandwidth of 10.7 nm and 5.5$^{\circ}$, respectively.vely.