• 한국농림기상학회지
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• 제21권4호
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• pp.358-365
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• 2019

영농형 태양광 발전은 기존 농지에 태양광 패널을 설치하여 농지 보존과 일정 수확량 유지를 전제로 전기 생산도 병행하는 시스템이다. 최근 태양광 부지 수요 충족 및 농촌 경쟁력 제고를 위한 방안으로 주목 받고 있다. 따라서, 본격적인 개발에 앞서 영농형 태양광 패널 하부에서의 경작지 차광 정도를 분석하는 것이 작물 생육·수확량 변동 예측에 반드시 필요할 것이다. 본 실험은 연구용 영농형 태양광 건설에 앞서, 영농형 태양광 시설 규격과 유사한 모의 차광 시설을 설치하고 하부의 광합성유효복사량 특성을 분석하였다. 차광막 하부와 외부의 광합성유효복사량 차이는 일사광에서 산란광 비율이 낮아질수록 증가하였는데, 최대 17.08 mol/㎡/day (맑은 날), 최소 3.03 mol/㎡/day (흐린 날)이었다. 이러한 광 조건 변화는 벼의 초기 생육에 있어 초장의 증가와 주당경수의 감소를 가져왔다.

• 생물환경조절학회지
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• 제18권3호
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• pp.244-252
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• 2009

본 연구는 우리나라와 네덜란드의 상업적인 온실에서 파프리카의 전체 재배기간 동안 시설 내 외부 기상환경을 비교 분석함으로써 양국간 생산량 차이 원인 분석을 함으로써 우리나라 파프리카의 시설내부 재배환경조건을 최적화하기 위한 기초자료 확보를 위하여 이 연구를 수행하였다 두 온실 모두 'Derby'를 공시하여 우리나라는 3.75주/$m^2$(2 stems), 네덜란드는 2.5주/$m^2$(3 stems), 1.875주/$m^2$(4 stems)로 암면에 수경재배 하였다. 두 온실모두 재식주수는 상이하였지만, 줄기밀도는 7.5m$^2$/stems로 같았다. 양국의 파프리카 주별 생장량은 크게 차이가 나지 않았으나, 전체 마디 대비 수확마디는 네덜란드가 우리나라에 비해 두 배 이상 높았다. 전체 재배기간 동안 일중 평균 광량은 우리나라 14.5MJ/$m^2$/day, 네덜란드 12.1MJ/$m^2$/day로 우리나라가 19.8% 높았다. 시설내부 24시간 평균온도는 우리나라 $21.6^{\circ}C$, 네덜란드 $21.2^{\circ}C$로 비슷한 경향을 보였지만, 우리나라의 시설내부 온도관리가 변화폭이 심하였다. 전체 작기의 시설내부 수분부족분(HD)은 우리나라 4.5g/$m^3$, 네덜란드 3.5g/$m^3$로 우리나라의 시설내부가 더 건조하게 관리되었다. 특히 우리나라 야간의 수분부족분은 매우 변화폭이 컸다. 주간 평균 이산화탄소 농도는 우리나라와 네덜란드가 반대의 경향으로 관리되었고 이는 네덜란드의 겨울철 난방 시 배출되는 이산화탄소를 시설내부로 시용한 결과에 기인한다. 일중 외부 광량 대비 시설내부 24시간 평균온도와 주간 이산화탄소 농도는 우리나라는 매우 불균일하게 관리되었지만 네덜란드의 경우 균일하게 관리되었다. 네덜란드의 시설 내.외부 환경은 우리나라에 비해 균일하게 관리되었고, 우리나라의 불균일한 시설내부 환경은 작물의 불균일한 생육을 유도할 것으로 판단된다.

• 전자공학회논문지
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• 제52권6호
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• pp.32-40
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• 2015

본 논문에서는 무인항공기에 탑재된 안테나 간의 간섭을 고려한 안테나 최적 위치 분석에 대해서 서술하였다. 분석은 전방향성 안테나들 중 운용 주파수 대역이 인접하고, 상호 간 이격거리가 가까운 곳에 위치한 안테나들을 선정하여 수행하였다. 분석을 수행한 안테나는 제어용 데이터링크, TCAS(Traffic Collision & Avoidance System), IFF(Identification Friend or Foe), GPS(Global Positioning System)와 RALT(Radar ALTimeter) 안테나들이다. 안테나 최적 위치 분석은 세 단계로 구분된다. 첫 번째 단계는 안테나 용도, 형상 및 방사패턴을 고려한 안테나 초기 위치 선정 후 안테나 장착 시 무인항공기 구조물에 의한 안테나 방사패턴과 반사손실 특성 변화를 관찰하여 최적의 특성을 갖는 지점을 선정하는 것이다. 두 번째 단계는 안테나 간의 결합특성과 송신 안테나의 불요파 세기 및 수신 안테나의 최저수신감도를 고려하여 안테나 간 간섭 정도를 분석하는 것이다. 간섭이 발생할 경우, 간섭이 미발생하는 최소이격거리를 분석하여 간섭이 발생하지 않는 최적 위치를 선정한다. 마지막 단계는 안테나 간 추가 거리 이격으로도 간섭이 제거되지 않을 경우, 안테나 간 주파수 이격 분석을 통한 주파수 간섭 대책을 확정하는 것이다. 이러한 분석 과정은 개발단계에서 안테나 간 간섭을 예측하여 간섭이 발생하지 않는 안테나 최적 위치 선정에 유용하게 사용된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.107-114
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• 1999

The large-scale distribution of crops Is usually determined by climate. We present the results of a climate-crop prediction based on spatial bio-physical process model approach, implemented in a GIS (Geographic Information System) environment using several regional and global agriculture-environmental databases. The model utilizes daily climate data like temperature, rainfall, solar radiation being generated stocastically by in-built model weather generator to determine the daily biomass and finally the crop yield. Crops are characterized by their specific growing period requirements, photosynthesis, respiration properties and harvesting index properties. Temperature and radiation during the growing period controls the development of each crop. The model simulates geographic/spatial distribution of climate by which a crop-growing belt can also be determined. The model takes both irrigated and non-irrigated area crop productivity into account and the potential increase in productivity by the technical means like mechanization is not considered. All the management input given at the base year 1995 was kept same for the next twenty-year changes until 2015. The simulated distributions of crops under current climatic conditions coincide largely with the current agricultural or specific crop growing regions. Simulation with assumed weather generated derived climate change scenario illustrate changes in the agricultural potential. There are large regional differences in the response across the country. The north-south and east-west regions responded differently with projected climate changes with increased and decreased productivity depending upon the crops and scenarios separately. When water was limiting or facilitating as non-irrigated and irrigated area crop-production effects of temperature rise and higher $CO_2$ levels were different depending on the crops and accordingly their production. Rise in temperature led to yield reduction in case of maize and rice whereas a gain was observed for wheat crop, doubled $CO_2$ concentration enhanced yield for all crops and their several combinations behaved differently with increase or decrease in yields. Finally, with this spatial modeling approach we succeeded in quantifying the crop productivity which may bring regional disparities under the different climatic scenarios where one region may become better off and the other may go worse off.

• 대기
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• 제27권3호
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• pp.301-316
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• 2017

This study analyzes the spatio-temporal variability of terrestrial carbon flux and the response of land carbon sink with climate factors to improve of understanding of the variability of land-atmosphere carbon exchanges accurately. The coupled carbon-climate models of CMIP5 (the fifth phase of the Coupled Model Intercomparison Project) and CT (CarbonTracker) are used. The CMIP5 multi-model ensemble mean overestimated the NEP (Net Ecosystem Production) compares to CT and GCP (Global Carbon Project) estimates over the period 2001~2012. Variation of NEP in the CMIP5 ensemble mean is similar to CT, but a couple of models which have fire module without nitrogen cycle module strongly simulate carbon sink in the Africa, Southeast Asia, South America, and some areas of the United States. Result in comparison with climate factor, the NEP is highly affected by temperature and solar radiation in both of CT and CMIP5. Partial correlation between temperature and NEP indicates that the temperature is affecting NEP positively at higher than mid-latitudes in the Northern Hemisphere, but opposite correlation represents at other latitudes in CT and most CMIP5 models. The CMIP5 models except for few models show positive correlation with precipitation at $30^{\circ}N{\sim}90^{\circ}N$, but higher percentage of negative correlation represented at $60^{\circ}S{\sim}30^{\circ}N$ compare to CT. For each season, the correlation between temperature (solar radiation) and NEP in the CMIP5 ensemble mean is similar to that of CT, but overestimated.

• 한국해양공학회지
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• 제20권6호
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• pp.101-107
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• 2006

Recently, with the increase in requirements for marine development, a marine urbanism is being visualized, with more and more huge-scale structures at the scope of the ocean space utilization. In particular, a pontoon-type structure has attracted attention, since The Floating Structures Association of Japan proposed a new concept as the most suitable one of floating airports. The Very Lage Floating Structure (VLFS) is considered a flexible structure, for a quite large length-to-breadth ratio and its geometrical flexibility. The main objective of this study is to makean exact and convenient prediction about the hydro-elastic response on very large offshore structures in waves. The numerical approach for the hydro-elastic responses is based on the combination of the three dimensional source distribution method and the dynamic response analysis method, which assumed a dividing pontoon type structure, as many rigid bodies connected elastic beam elements. The established hydo-elastic theory was applied to the radiation forces caused by motions of a whole structure, formulated using the global coordinate system, which has the origin at the center of the structure. However, in this paper, we took radiation forces, occurred by individual motions of floating bodies, into consideration. The calculated results show good agreement with the experimental and calculated results by Yago.

• 한국환경과학회지
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• 제24권11호
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• pp.1417-1430
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• 2015

In this study we were to explore the seasonal variation of water temperature distributions before and after weir construction at Gumi, Chilgok, Gangjung(Goryung), Dalsung in the Nakdong River using Landsat satellite images. Relationship between in-situ water temperature and radiance values of Landsat-5, 7, 8 satellite images showed high correlation. Seasonal variation of water temperature in Nakdong River showed that the fluctuation ranges of water temperature before weir construction were larger than those after weir construction. This indicated that the variation of water temperature is due to the difference of heat storage volume by weir construction and dredging work. In particular, the water temperature after weirs construction in autumn was 4-8 times lower than that before weirs construction. Water temperature after weir construction decreased in spring and summer at the downstream of Gumi weir and Gangjung(Goryung) weir, and the upstream of Dalsung weir. In autumn and winter, the water temperature after weir construction increased in the upstream and downstream of the whole weirs except upstream of Gumi weir. Relationship between water temperature and meteorological elements (air temperature, wind speed, sunshine, radiation) showed high correlation of above 94% in air temperature, and then radiation was high correlation before and after 65%.

• 항공우주기술
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• 제8권2호
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• pp.105-112
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• 2009

위성발사체(KSLV)발사에 있어서 Telemetry data는 발사임무수행 및 비행안전통제를 위해서 매우 중요한 자료이다. 따라서 발사체의 전체 비행구간 동안에 Telemetry 신호를 안정적으로 수신하는 것은 매우 중요하며, 이를 위하여 우주센터에서는 고흥 센터, 제주추적소 및 해상의 다운레인지를 운용하고 있다. 본 문서에서는 발사임무설계에 따른 예상비행궤적 및 발사체 자세, 추적소 위치를 고려하여 각 추적소의 임무구간에 신호를 안정적으로 수신할 수 있는지를 판단하는 Link Margin 및 통신신뢰도를 분석한다. 보다 정확한 분석을 위해서는 예상비행궤적 및 추적소 위치를 고려하여 발사체기준의 추적소방향(Aspect angle 및 roll angle)에 대한 탑재송신부 유효방사전력(EIRP: Effective Isotropic Radiation Power) 특성을 사용하여야 하나, 본 분석에서는 가용자료의 한계로 95% spatial coverage 유효방사전력을 사용하였다.

• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.166-175
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• 2017

Background: This study presents food ingestion standards for radioactivity that can be applied in nuclear emergency exposure situations, and discusses the validity of the current domestic standards. Materials and Methods: This study derived food ingestion standards for radiocesium and radioiodine using domestic food intake rates and intervention levels, which serve as a basis for determining the necessity of public protective actions, and then compared them with the existing guidelines. Operational intervention levels were also derived using domestic food intake rates, and were compared with those of the International Atomic Energy Agency. Results and Discussion: The derived activity concentrations for food ingestion standards of radiocesium for infants were higher than those in the Act on Physical Protection and Radiological Emergency (APPRE) for all food categories, while for adults, the derived activity concentrations for drinking water and milk appeared to be slightly lower. The derived activity concentrations for vegetables, fruits, and grains were greater than those in the guidelines of the APPRE, while the derived activity concentrations for meat and seafood were similar to those in the APPRE. The derived activity concentrations for radioiodine were greater than both domestic and global standards. The calculated operational intervention levels (OILs) based on domestic food intake rates were greater than the IAEA's default OIL6 values for most radionuclides, except for a few ${\alpha}$-radionuclides. Conclusion: The current domestic guidelines turned out to be conservative overall, compared to the present results that were calculated using domestic food intake rates. It is recommended that the domestic guidelines should be revised and complemented transparently through an in-depth review by stakeholders on a solid scientific basis.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4098-4105
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• 2021

The aim of this study is to calculate the JO-IMRT dose distributions based on the AAPM TG-119 using Monte Carlo (MC) simulation and Prowess Panther treatment planning system (TPS) (Panther, Prowess Inc., Chico, CA). JO-IMRT dose distributions of AAPM TG-119 were calculated by the TPS and were recalculated by MC simulation. The DVHs and 3D gamma index using global methods implemented in the PTW-VeriSoft with 3%/3 mm were used for evaluation. JO-IMRT dose distributions calculated by TPS and MC were matched the TG-119 goals. The gamma index passing rates with 3%/3 mm were 98.7% for multi-target, 96.0% for mock prostate, 95.4% for mock head-and-neck, and 96.6% for C-shape. The dose in the planning target volumes (PTV) for TPS was larger than that for the MC. The relative dose differences in D99 between TPS and MC for multi-target are 1.52%, 0.17% and 1.40%, for the center, superior and inferior, respectively. The differences in D95 are 0.16% for C-shape; and 0.06% for mock prostate. Mock head-and-neck difference is 0.40% in D99. In contrast, the organ curve for TPS tended to be smaller than MC values. JO-IMRT dose distributions for the AAPM TG-119 calculated by the TPS agreed well with the MC.