• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.450-452
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• 2003

In the present investigation, an estimation of the growth of heat island development of Tokyo metropolis which accounts nearly 100 sq. km of areal spread has been carried out. Band 6 data of LANDSAT TM (Thematic Mapper) data acquired on August 1984 and 1994 have been used for estimating the expansion of the heat island development. Since the vegetation decrease is usually associated with the heat island development, a ratio of green covering has also been assessed using TM data. In order to establish the relationship with the air temperature, AMeDAS(Automated Meteorological Data Acquisition System) data have been correlated.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.528-530
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• 2003

We present here, some of the studies carried for estimation of rainfall over land and oceanic regions in and around South Korea. We use active and passive microwave measurements from TRMM ? TMI and Precipitation Radar (PR) respectively during a typhoon even named ? RUSA that took place during 30 Aug. 2002. We have followed due approach by Yao at. all (2002) and examined the performance of their algorithm using two main predictor variable, named as Scattering Index (SI) and Polarization Corrected Brightness Temperature (PCT) while using TMI data. The rainfall fnus estimated using PST and SI shows some Underestimation as compared to the 2A25 rainfall products from the PR in common area of overlap. A larger database thus would be used in future. To establish a new rain rate algorithm over Korean region based on the present case study.

• Nuclear Engineering and Technology
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• v.30 no.6
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• pp.609-616
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• 1998

Cast duplex stainless steels are extensively used for primary pressure boundary components. These components are, however, embrittled due to the precipitation of $\alpha$' phase by spinodal decomposition and other processes when exposed to reactor operating temperature for a design lifetime or life extension conditions. This report presents a procedure for estimating the current condition and the residual life of safety-related stainless steel components by using ANL database and correlations. The database of Charpy impact energy suggests that CF-8M grade is the most susceptible to thermal aging and CF-3 grade is the least. Thus, the integrity of CF-8M alleys may be degraded seriously and the degree of deterioration may exceed acceptance limit after several years of service in the nuclear reactors.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.469-473
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• 1994

The E-and Z-isomers of 1-methyl-l-phenyl-2-neopentylsilene, generated by the sealed tube thermolyses of their anthracene adducts are stereospecifically trapped by trimethylmethoxysilane to give diastereomeric adducts. The temperature dependence of the ratio of the two diastereomers obtained when the silene formed from the pure E-or Z-anthracene adduct was trapped at higher temperatures permitted the determination of an activation energy for the silene isomerization. The activation energies for the E-to Z-and Z-to E-silene isomerization are $45{\pm}$6 and $20{\pm}4$ kcal $mol^{-1}$, respectively. The significance of these values is discussed.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.140-140
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• 2019

본 연구에서는 Terra MODIS 위성자료와 Tensorflow를 활용해 1 km 공간 해상도의 토양수분을 산정하는 알고리즘을 개발하고, 국내 관측 자료를 활용해 검증하고자 한다. 토양수분 모의를 위한 입력 자료는 Terra MODIS NDVI(Normalized Difference Vegetation Index)와 LST(Land Surface Temperature), GPM(Global Precipitation Measurement) 강우 자료를 구축하고, 농촌진흥청에서 제공하는 1:25,000 정밀토양도를 기반으로 모의하였다. 여기서, LST와 GPM의 자료는 기상청의 종관기상관측지점의 LST, 강우 자료와 조건부합성(Conditional Merging, CM) 기법을 적용해 결측치를 보간하였고, 모든 위성 자료의 공간해상도를 1 km로 resampling하여 활용하였다. 토양수분 산정 기술은 인공 신경망(Artificial Neural Network) 모형의 딥 러닝(Deep Learning)을 적용, 기계 학습기반의 패턴학습을 사용하였다. 패턴학습에는 Python 라이브러리인 TensorFlow를 사용하였고 학습 자료로는 농촌진흥청 농업기상정보서비스에서 101개 지점의 토양수분 자료(2014 ~ 2016년)를 활용하고, 모의 결과는 2017 ~ 2018년까지의 자료로 검증하고자 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1190-1196
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• 2004

Significant air temperature increases in urban areas are known as the heat island phenomenon in a global scale. Therefore, we propose numerical model in order to analyze quantitative effects of building environmental factors on the heat island phenomenon in urban area. In this paper, we propose a predicting model to analyze the heat island phenomenon quantitatively. Using this model, numerical simulation is performed in order to analyze quantitative effects of many factor on the heat island phenomenon.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1006-1011
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• 2006

In this study, a rational procedures for estimation of insulation thickness for condensation control or personnel protection has been investigated. Both horizontal pipe and vertical wall configuration are included. Design parameters are pipe diameter or, height of the wall, thermal conductivity, emissivity, and operating temperatures. The results Indicated that the surface emissivity plays a very important role in the design of insulation for the purpose of surface temperature control, especially in natural convection situation. radiation heat transfer coefficients for some new insulation material surface, such as elastomers, estimated to be more than 90% of the total surface heat transfer coefficient. Adequate revision of specifications or standards has been also suggested.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.187-188
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• 2018

본 논문에서는 영구자석 동기 전동기의 온도 변화를 인공신경망을 통해 예측 및 추정하는 방법을 제시한다. 고정자와 회전자의 온도와 속도, 토크를 입력으로 하여 다음 샘플링 주기까지의 온도 변화를 출력하는 인공 신경망이 제시되었다. 여러 운전점에서 수집된 온도 데이터를 사용하여 훈련된 신경망은 임의의 온도를 시작 온도로 설정하고 출력인 온도 변화를 적분하여 현재의 온도를 추정한다. 제시된 방식은 시뮬레이션을 통해 검증되었고 훈련에 사용되지 않았던 운전경로에 대해 항상 $2^{\circ}C$ 이하의 추정 오차 성능을 보였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.496-502
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• 2020

The reliability of a solid-state transformer (SST) is one of the important aspects to consider when replacing a conventional low-frequency passive transformer with SST for urban railway vehicles. Lifetime evaluation of SST in the design phase is therefore essential in guaranteeing a certain SST reliability. In this study, a lifetime evaluation of power semiconductor devices in SST is performed with respect to temperature stress. For a case study, a 3 MW SST with three kinds of power modules (one IGBT module and two SiC-MOSFET modules) is used for the lifetime estimation under the operation profile of urban railway vehicles.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.274-274
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• 2023

기후변화의 영향으로 겨울철 적설의 양상이 과거와는 많이 달라진 것으로 보인다. 따라서 미래의 적설이 어떤 확률로 발생할 것인지도 과거에 비해 많이 달라질 것으로 예상된다. 하지만 어떤 정도로 달라질 것인지는 정확하게 알 수가 없다. 본 연구에서는 이를 합리적으로 추정하기 위해 일본에서 수행한 대규모 기후 앙상블 모의실험 결과로 생성된 d4PDF(Data for Policy Decision Making for Future Change) 자료 중 적설과 기온 자료를 이용하여 일 최심적설심을 모의하고 연최대치계열을 작성하여 과거의 최심적설심 연최대치분포와 비교하여 분위사상법을 통해 모형의 오차를 보정한 후 미래 지구평균온도 상승 시의 기후모의 결과에 적용함으로써 지구평균온도 상승 정도에 따라 우리나라의 적설양상과 확률적설심이 어떻게 변화할 것인지 추정해 보았다. 연구의 결과는 미래 적설과 관련된 설계와 방재 목적에 참고적으로 활용될 수 있을 것이다.