• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2012년도 춘계학술논문집 2부
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• pp.569-572
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• 2012

식물공장의 다양한 건물형태에 따른 냉난방부하의 차이를 DesignBuilder를 이용하여 해석하였다. 엽채류 중 상추의 생육 적정온도인 $20^{\circ}C$를 실내온도로 설정하고 식물공장 외벽에 단일창호를 적용하여 온실형태에 따른 냉난방부하 변화를 계산하였다. 보광이 없는 건물자체의 냉난방부하를 계산한 결과 KNU 식물공장 단위유닛과 반원 온실형 식물공장이 냉방부하가 가장 적었다. 보광 적용 후에는 전반적으로 KNU 식물공장 단위유닛과 직사각형 식물공장이 양호한 냉난방 성능을 보여주었다. KNU 식물공장 창호의 면적이 와이드 스팬형보다 크기 때문에 건설비용의 증가가 예상되지만 회전형 스마트 조명 제어시스템을 적용하게 되면 재배면적을 넓히고 공간활용에 유리하다. 또한 LED 사용량을 줄일 수 있어 냉방부하와 보광에 드는 비용을 절감할 수 있다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.337-350
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• 1999

Thick diamond film having ~700${\mu}{\textrm}{m}$ thickness was deposited on polycrystalline molybdenum (Mo) substrate using high power (4kW) microwave plasma enhanced chemical vapor deposition (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconductivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• 한국결정성장학회지
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• 제9권4호
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• pp.441-445
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• 1999

Thick diamond film having $~700\mu\textrm{m}$ thickness was deposited on polycrystalline molybdenum(Mo) substrate using high power (4 kW) microwave plasma-enhanced chemical vapor depostion (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconcuctivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• 대기
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• 제34권2호
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• pp.139-151
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• 2024

The Yeongdong region has suffered from severe snowstorms and the relevant damage such as traffic accidents on slippery roads, and the collapse of greenhouses and temporary buildings. While a lot of research on snowfall has been conducted, the detailed study of snow crystals' phase and habit through intensive observations and the relevant microphysical analysis is still lacking. Therefore, a snowflake camera, PARSIVEL, and intensive radiosonde soundings were utilized to investigate phase and habit changes in solid precipitation. Two remarkable episodes of phase and habit changes were selected such as 19 March 2022 and 15 February 2023. Both events occurred in the synoptic condition of the High in the north and the Low passing by the south, which was accompanied by rapid temperature cooling below 2.5 km. During the events of a short period between 3 to 6 hours, the temperature at 850 hPa decreased by about 4 to 6℃. This cooling led to a change in the main habit of snow particles from riming to aggregate, identified with both MASC and PARSIVEL. Meanwhile, the LDAPS model analyses do not successively represent the rapid cooling and short-term variations of solid precipitation, probably by virtue of overestimating low-level equivalent potential temperature during these periods. The underlying causes of these the low-level temperature variations within 6 hours, still remain unclear. It might be associated with mesoscale orographic phenomenon due to the mountains and East Sea effects, which certainly needs an intensive and comprehensive observation campaign.

• 한국컴퓨터정보학회논문지
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• 제27권9호
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• pp.49-57
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• 2022

현재 우리 사회는 기후 문제와 세계 인구 증가로 인해 식량 부족 문제가 대두되고 있다. 이를 해결할 방안으로 인공지능(Artificial Intelligent, AI)와 정보통신기술(Information and Communication Technology, ICT)을 접목 시킨 다중 원격 제어 스마트팜을 제안한다. 제안하는 스마트팜은 ICT 기술을 접목시켜 공간과 시간에 제약 없이 원격으로 제어 및 관리하고 작물의 생육환경을 다중 제어한다. 아두이노를 활용하여 스마트폰 애플리케이션(Application, APP)을 통한 다중 제어가 가능한 스마트팜 시스템을 제안하였고, 딥러닝 기술을 적용하여 작물의 생장을 실시간으로 관찰하면서 다양한 데이터 확보 및 진단 기능을 가지는 AI기술을 포함하였다. 스마트팜 내의 각종 센서들을 제어하고 센서들의 데이터 값을 구축한 데이터베이스에 저장하여 사용자가 APP을 통하여 확인할 수 있도록 하였다. 사용자는 APP에서 현재 기상을 참고하여 제어할 수 있도록 하였고 캠을 통해 생육 환경을 실시간으로 확인할 수 있다. 다중 작물을 위한 다중 제어에는 2개 이상의 생육 환경에 대한 각각의 LED, COOLING FAN, WATER PUMP를 적용하여 사용자가 편리하게 제어할 수 있도록 구현하였다. 그리고 딥러닝 기술을 사용하여 TensorFlow 프레임워크를 통해 생육 단계를 진단해주는 APP을 구현하여 사용자가 현재 작물이 어느 단계의 생육 상태인지 손쉽게 진단할 수 있도록 도와주는 애플리케이션을 개발 하고 적용하였다.

• 한국수정란이식학회지
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• 제26권1호
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• pp.13-17
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• 2011

Research in the area of equine artificial insemination (AI) has led to its increased application in field trials. However, procedures for equine semen collection, cooling and freezing of semen and artificial insemination need further improvement. In experiment 1, we investigated the percentage of total motility (TM) and progressive motility (PM) of sperms at after-collection, cooled-diluted, cooled-transported or frozen-thawed semen. In experiment 2, mares were inseminated with either cooled-diluted, cooled-transported or frozen-thawed semen. In experiment 3, we examined the effect of buffer (skim-milk extender), which was infused into the uterus at the time of AI with frozen-thawed semen. In experiment 4, we compared AI pregnancy rates for mares ovulating spontaneously versus after treatment with hCG. In experiment 1, the average percentage of TM was decreased from 75.3% to 14.4% at the stage of after-collection to frozen-thawed semen (p<0.05). The average percentage of PM was 58.2% and 59.6% at after-collection and cooled-diluted, but it was significantly increased 71.7% after frozen-thawed (p<0.05). In experiment 2, the pregnancy rates after AI using cooled-diluted, cooled-transported and frozen-thawed semen were 60%, 50% and 37.5%, respectively, and similar among treatments. In experiment 3, the pregnancy rate of mares infused with buffer at AI was 40% which was higher than that with no buffer (10%). In experiment 4, the pregnancy rates of mares were similar between ovulated spontaneously (25%) and ovulated with hCG (50%). The results suggest that equine semen that has been cooled-diluted, cooled-transported or frozen can be successfully used to establish AI, pregnancy and foal production. Also, the pregnancy rates after AI can be increased by infusing buffer into the uterus at AI or by inducing ovulation with hCG, but further study is need.

• KIEAE Journal
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• 제16권6호
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• pp.123-128
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• 2016

Purpose: In order to save the energy consumption of buildings, buildings have been constructed with high performance insulation or airtightness. However, high performance insulation or air tightness has led to a poor indoor air quality. Therefore, HRV(Heat Recovery Ventilator) has received attention to save the energy consumption and insure a good air quality. Because existing research is almost about the performance of HRV in residential buildings, This study analyzed the effect of HRV on cooling energy consumption in commercial office building. Method: This study was proceeded at commercial office building in In-cheon. In order to evaluate the energy consumption of HRV, this study proposed two methods: estimating energy consumption of the room installed AHU(Air Handling Unit) system; estimating energy consumption of the room installed HRV system. Therefore, comparison of two methods was proceeded to evaluate energy performance of each method. Result: As the result of comparison between rooms installed AHU and HRV, the experiment showed that energy consumption of the room installed HRV system is about 22% less than the room of AHU system. This conclusion is considered because the room installed HRV system have maintained temperature well at set point temperature $26^{\circ}C$.

• 자원ㆍ환경경제연구
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• 제20권2호
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• pp.381-398
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• 2011

최근 동계 전력피크가 빈번히 발생하면서 전력수급 차질에 대한 우려가 높아지고 있다. 경기회복에 따른 산업용 전력수요가 증가한 것도 원인이지만 이상 한파에 따라 가정 상업 부문의 전기난방수요가 급증한 것이 주된 원인으로 파악된다. 특히 전기히트펌프(EHP)의 보급 확산으로 상업용 난방수요가 급증하고 있다. EHP의 보급 확산은 낮은 전기요금으로 가스히트펌프(GHP)에 비해 상대적으로 저렴한 냉난방비용 때문인 것으로 분석된다. 전기요금의 왜곡은 그 자체로도 문제이지만 이로 인해 파생되는 문제가 더 크다고 할 수 있다. 왜곡된 전기요금은 냉난방 열원에 대한 쏠림 현상을 불러오고 국가 전체적인 자원배분의 비효율성을 초래한다는 것이다. 근본적인 대책의 핵심은 전기요금을 적정 수준으로 현실화시키고 전기요금 체계를 소비자가 합리적으로 반응할 수 있는 구조로 바꾸는 것이다. 또한 효율적으로 전력수요를 관리할 수 있는 방안을 찾아야 한다.

• Computers and Concrete
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• 제15권1호
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• pp.103-126
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• 2015

Thermal effects are significant loads for assessing concrete dam behaviour during operation. A new methodology to estimate thermal loads on concrete dams taking into account processes which were previously unconsidered, such as: the evaporative cooling, the night radiating cooling or the shades, has been recently reported. The application of this novel approach in combination with a three-dimensional finite element method to solve the heat diffusion equation led to a precise characterization of the thermal field inside the dam. However, that approach may be computationally expensive. This paper proposes the use of a new one-dimensional model based on an explicit finite difference scheme which is improved by means of the reported methodology for computing the heat fluxes through the dam faces. The improved model has been applied to a case study where observations from 21 concrete thermometers and data of climatic variables were available. The results are compared with those from: (a) the original one-dimensional finite difference model, (b) the Stucky-Derron classical one-dimensional analytical solution, and (c) a three-dimensional finite element method. The results of the improved model match well with the observed temperatures, in addition they are similar to those obtained with (c) except in the vicinity of the abutments, although this later is a considerably more complex methodology. The improved model have a better performance than the models (a) and (b), whose results present larger error and bias when compared with the recorded data.

• 한국정보전자통신기술학회논문지
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• 제17권4호
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• pp.255-265
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• 2024

환경 문제와 에너지 효율성을 향상시키기 위하여 전기자동차를 도입함으로서 이에 따른 연구가 급증하고 있다. 그러나 전기 자동차 분야의 연구 동향을 전체적으로 파악기 위해서는 방대한 데이터를 체계적으로 분석할 필요가 있다. 본 연구에서는 SCIE 데이터베이스에서 수집한 36,519편의 전기 자동차 관련 논문을 바탕으로 LDA주제 모델링을 수행하여 전기 자동차 분야의 연구 동향을 체계적으로 분석하고 주요 연구 주제를 파악하였다. 데이터 분석 결과, 총 10개의 주요 주제가 도출되었으며, 이 중 3개 주제는 상승 추세를 보이는 핫 토픽으로 확인되었으며 그 분야는 Electric Vehicle Charging Infrastructure, Energy and Environmental Policy, Optimization and Algorithms이었다. 그러나, 5개 주제는 하락 추세를 보이는 콜드 토픽으로 분류되었으며 그 분야는 Battery Temperature and Cooling, Battery Materials and Chemistry, Motor and Mechanical Design, Control Strategies and Systems, Battery Components and Materials이었다. 본 연구에서는 전기 자동차 분야의 최신 연구 동향을 이해하는 데 중요한 기초 자료를 제공하였으며, 전기자동차 관련 연구자가 연구 주제 선정에 필요한 유용한 정보를 제공하였다.