• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.38 no.7
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• pp.4-7
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• 2009

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.12
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• pp.963-969
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• 2021

The wind data measured from local meteorological masts is used to evaluate wind speed distribution and energy production in the specified site for wind farm However, wind data measured from meteorological masts often contain missing information or insufficient desired height or data length, making it difficult to perform wind turbine control and performance simulation. Therefore, long-term continuous wind data is very important to assess the annual energy production and the capacity factor for wind turbines or wind farms. In addition, if seasonal influences are distinct, such as on the Korean Peninsula, wind data with seasonal characteristics should be considered. This study presents methodologies for generating synthetic wind that take into account fluctuations in both wind speed and direction using the hidden Markov model, which is a statistical method. The wind data for statistical processing are measured at Maldo island in the Kokunnsan-gundo, Jeonbuk Province using the Automatic Weather System (AWS) of the Korea Meteorological Administration. The synthetic wind generated using the hidden Markov model will be validated by comparing statistical variables, wind energy density, seasonal mean speed, and prevailing wind direction with measurement data.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.243-248
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• 2022

As the scope of use of portable and wearable electronic devices is expanding, the limitations of heavy and bulky solid-state batteries are being revealed. Given that, it is urgent to develop a small energy harvesting device that can partially share the role of a battery and the utilization of energy sources that are thrown away in daily life is becoming more important. Contact electrification, which generates electricity based on the coupling of the triboelectric effect and electrical induction when the two material surfaces are in contact and separated, can effectively harvest the physical and mechanical energy sources existing in the surrounding environment without going through a complicated intermediate process. Recently, the interest in the harvest and utilization of wind energy is growing since the wind is an infinitely ecofriendly energy source among the various environmental energy sources that exist in human surroundings. In this study, the optimization of the energy harvesting device for the effective harvest of wind energy based on the contact electrification was analyzed and then, the utilization strategy to maximize the utilization of the generated electricity was investigated. Natural wind based Fluttering TENG (NF-TENG) using fluttering film was developed, and design optimization was conducted. Moreover, the safe high voltage generation system was developed and a plan for application in the field requiring high voltage was proposed by highlighting the unique characteristics of TENG that generates low current and high voltage. In this respect, the result of this study demonstrates that a portable energy harvesting device based on the contact electrification shows great potential as a strategy to harvest wind energy thrown away in daily life and use it widely in fields requiring high voltage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.4
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• pp.293-302
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• 1991

The anomalous sea level deviation or storm surge caused by the typhoon Thelma in 1987 are studied analysing tidal observation data at 7 stations in the south coast of Korean peninsula. The surges are calculated by subtracting the predicted tidal height from the observed tidal record. The tidal deviation at these stations along the coast are discussed in association with meteorological data. The sea level anomalies are studied by means of the empirical orthogonal function (EOF) analysis and the fast fourier transform (FFT) method. The results of analysis suggest that the peak value of surges are higher at the tidal stations in semi-enclosed bay and in long narrow channel than at the ones facing with the open sea. From the result of EOF analysis, the temporal and spatial fluctuations of storm surge can be described by the first EOF mode, which explains 63% of the total variances during the passage of typhoon Thelma. The deviation of storm surge in the studied areas indicates bi-modal peak during the passage of typhoon Thelma. From the results of FFT spectrum analysis, the peak of energy of autospectrum for surge, atmospheric pressure, and wind stress appeared at low frequency fluctuations band of 0.008-0.076 cph over the 4 stations. Auto-correlation function of surge showed periodicity, while that of atmospheric pressure and wind stress indicates no periodicity. The result of FFT analysis shows that the typhoon surges are related chiefly with the change of atmospheric pressure in an open bay (Cheju Harbor), but with the wind stress in a semi-enclosed bay (Yeosu Harbor).

• The Korea Swine Journal
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• v.12 no.9 s.133
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• pp.136-139
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• 1990

자돈의 폐사는 대부분 생후3일 이내에 발생한다.이러한 손실을 줄이는 방법중에 하나가 저장에너지를 많이 가진 자돈을 분만시키고, 분만후에는 모돈에게 지방함량이 많은 젖을 분비하게 하여 육설율을 높이는 것이다.이와 같은 목적을 위해서는 임신말기에 고에너지 사료인 유지사료를 첨가하여 급여하는 것이 바람직하다

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.361-361
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• 2007

• The Magazine for Energy Service Companies
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• s.15
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• pp.32-33
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• 2002

ESCO사업은 향후 $2\~3$년 후가 고비라는 생각입니다. ESCO사업을 수행하는데 가장 큰 걸림돌이랄 수 있는 부채증가문제로 인하여 ESCO들의 활동력이 저하되는 것을 극복하기 위해서는 현재의 ''성과배분제''에서 선진국에서 보편적인 ''성과보증제''로 이행되는 것이 바람직하다고 봅니다.

• JOURNAL OF ELECTRICAL WORLD
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• s.463
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• pp.74-79
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• 2015

전라남도 진도군 조도면에 위치한 섬 가사도. 이 섬마을 방문하려면 하루에 왕복 1차례 밖에 없는 배편을 이용해야 한다. 특별한 일이 아니고서야 방문할 마음조차 쉽사리 먹기 힘든 그러한 전형적인 섬마을이다. 이러한 섬마을에 일대 대변혁의 바람이 불기 시작했다. 지난 2012년 이후 정부와 한국전력공사가 추진하고 있는 마이크로그리드(MG)를 이용한 에너지 자립섬 시범단지로 자리매김했기 때문이다.

• The Magazine for Energy Service Companies
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• s.66
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• pp.34-37
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• 2010

예산부장에서 자금운용실장으로 발령 받은 지 약 6개월, 짧다면 짧고, 길다면 긴 시간 동안 그의 하루하루는 쏜살같이 지나갔다. 그의 말을 빌리면, 너무 바빠서 개인적인 목표나 바람 등은 생각할 틈도 없을 정도로 말이다. ESCO사업의 중심에 서며 ESCO산업의 활성화를 위해, 기업의 실질적인 도움을 건네주기 위해 불철주야로 뛰고 있는 이재우 자금운용실장을 만나보았다.

• The Science & Technology
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• v.33 no.12 s.379
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• pp.10-11
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• 2000

우리나라의 핵융합실험은 대형의 토카막으로 자기 핵융합실험인데 막대한 국력을 자기 핵융합장치 토카막에만 집중하는 것보다 그 예산의 일부나마 레이저 핵융합연구에 돌려 미래의 에너지 기술전쟁에 대비하는 것이 바람직하다. 10~30년후 레이저 핵융합 분야의 연구에 있어서 기술종속국이 되지 않기 위해선 관련 기반연구에 대한 우선 투자가 필수적이라고 생각한다.