• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1797-1800
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• 1996

In this study, the insulation selected in degra-dated-power cable has been observed and aging process about the insulation has been investigated. Most Insulation aging process initiates in the interface of semiconducting layer and the type of the process is the fractal form that was observed between the the semiconducting layer and insulation layer. It is possible to estimate degree of the degration of cable with breakdown test and obtained data have been used to get parameters in order to use Weibull distribution. With this method it is considered to be possible to estimate situation of degration and life prediction.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2015-2016
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• 2008

본 연구에서는 국내 배전용 개폐기의 교체주기를 설정하기 위하여, 제조사별 열화 가중치 및 최대 운영수명을 산출하였으며, 운영중인 개폐기에 대한 위험도 평가 알고리즘을 제안하였다. 또한 국내 배전용 개폐기의 교체주기를 설정 알고리즘을 현장에서 쉽게 사용하고, 측정 및 분석 데이터를 저장 및 상태추이 분석이 가능한 개폐기 수명평가 프로그램을 개발하였다.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.8-14
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• 2000

The remaining life estimation for the aged components in power plants as well as chemical plants are very important because mechanical properties of the components are degraded with time of service exposure in the high temperature. Since it is difficult to take specimens from the operating components to evaluate mechanical properties of components, accelerated aging technique are needed to estimate and analyse the material degradation. In the this study, test materials with 4 different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C$. And tensile test, $k_{IC}$ test, hardness test and Scanning Electron Microscope analysis were performed in order to evaluate the degradation of 1Cr-1Mo-0.25V steels.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.285-290
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• 2001

본 논문에서는 멀티미디어 서비스 요소 중의 하나인 VoIP(Voice Over Internet Protocol)망에서의 음성 품질에 대한 평가를 위해 VoIP망에서 송화자 내용- 발생과정에 있어서 어느 정도 완전히 표현되었는가를 나타내는 송화품질과 음성의 전송계를 통해 수화자에게 전달되는 과정에서 왜곡이나 잡음 등의 방해요인에 의해 열화되는 정도를 나타내는 전송품질, 그리고 수화자가 청각에서 신호처리 과정을 거친 송화자의 내용을 어느 징도 이해할 수 있는지를 나타내는 수화품질에 대한 주관적 방법을 평가한 후 통화품질을 측정한 내용을 분석하여 그 원인과 개선책에 대한 방법을 제시하고자 한다.

• Broadcasting and Media Magazine
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• v.25 no.2
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• pp.7-16
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• 2020

최근 Ultra-High Definition(UHD) 등의 고해상도 디스플레이가 시장에 등장하고 이에 따라 소비자의 요구가 커지면서 기존의 Full-High Definition(FHD)과 같은 저해상도(Low Resolution, LR) 영상을 고해상도(High Resolution, HR) 영상으로 변환할 수 있는 초해상화(Super-Resolution) 알고리즘에 대한 관심이 커지고 있다. 그러나 기존의 전통적인 초해상화 기법들은 고해상도 영상을 복원하는 과정에서 디테일한 부분의 화질 저화 및 열화가 존재하는 것을 확인할 수 있다. 본 논문에서는 이러한 문제를 해결하기 위해 최근 널리 연구되고 있는 딥러닝 기반의 초해상화 알고리즘 연구의 최신 기술 현황 및 동향을 소개하고자 한다. 딥러닝 기반의 초해상화 알고리즘은 기존의 전통적인 기법들에 비해 높은 성능을 보여주고 있으며 현재까지도 다양한 네트워크가 제안되며 활발히 연구되고 있다. 본 논문에서는 딥러닝 기반의 초해상화 알고리즘 중 대표적인 네트워크들을 분석하고 다양한 데이터 셋에 대한 해당 네트워크의 실험 결과를 통해 딥러닝 기반의 초해상화 알고리즘의 우수성을 확인하고자 한다.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.59-65
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• 2019

Phosphor particles ((Sr,Mg)₂ SiO₄:Eu²⁺ were suspended in deionized water in quartz cuvette and used for measuring liquid temperature field by using two-color-ratio method. In the temperature range of 23~77℃, it showed the relative error from 2.4% to 4% and the temperature sensitivity of 0.65 %/℃ at 30℃ and 0.95 %/℃ at 77 ℃. This performance is comparable to measurement techniques using thermographic liquid crystal or laser induced fluorescence or other thermographic phosphor particle. Among investigated potential error sources, the particle number density affected the intensity ratio and the temperature, but the effect of laser fluence was not evident.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.6
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• pp.323-329
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. The carbide morphologies were classified as acicular, pipe and globular type, and the number of carbides per unit area was measured for each type of carbides. The fine acicular carbides were found to diminish drastically in the initial stage of aging. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the magnetic property measurements such as saturation magnetization, coercivity and remanence. The saturation magnetization showed no distinct trend with aging time. However, the coercivity and remanence were observed to decrease rapidly in initial 920 hours of aging time and then decrease slowly afterwards.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.178-181
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• 2001

This paper presents the development of electromagnetic wave detecting equipment for diagnosis of enclosed switchboard. High voltage power equipments are very important equipment of the key industries and the private enterprise. Power line accidents are national plans because of those set off casualties lose of power equipments and communication networks. Therefore the necessity of the development of detecting for power equipment diagnosis is demand for prevention of high voltage equipment accidents. This paper is the development of electromagnetic wave detecting equipment for diagnosis of high voltage equipment. This paper establishes the diagnosis method for high voltage power equipments, that secures original technique and possesses detecting technique for electromagnetic wave. By the study we developed electromagnetic wave detector, and we applied this equipment application tests at the place constructed high voltage equipments.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.05a
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• pp.314-319
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• 2001

Most parts of facilities in domestic petroleum plants and power plants are needed to be abandoned, repaired or replaced, because in Korea they were built in the 1960s and, they have been used under severe conditions and exposed corrosive environments. 2.25Cr- lMo steels have excellent high-temperature mechanical properties. Therefore, the material have been widely used as heat exchanger tubes, boiler headers and its tubes in such industries. But, those microstructural evolutions in high temperature such as precipitation and carbide coarsening give a reason to degrade the material. Especially, in case of this material, carbides induced embrittlement(CIE) is the primary reason for degrading mechanical properties at over 50$0^{\circ}C$. In this paper, we introduce a electrochemical polarization method for detecting CIE quantitatively.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1894-1896
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• 2000

A Study on TOID system which can measure a degree of diagnosis oil Tr. TOID system uses porous ceramic sensor and accept a DC 2000V, this method is to accumulate carbon element generated from the both electrodes from the ingredients the sensor when being vaporized the oil. The main substance of our research were comparison between vaporizing detection result of the oil, gas analysis, withstand voltage, test of acid value, and to define a new technology of measurement.