• 한국농림기상학회지
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• 제23권2호
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• pp.134-140
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• 2021

농업용 유리온실 또는 플라스틱하우스의 투과율을 산정하거나 영농형 태양광 하부 작물의 수광량을 평가할 때, 그리고 작물 군락 광합성량을 모의하거나 분석할 때에 직달과 산란 일사량을 구분하여 접근할 필요가 있다. 본고에서는 산란과 직달 일사량 자료의 농업적 활용 촉진을 위해 나주에서 2019년 5월부터 2020년 11월까지 측정한 자료를 공개하였다. 또한, 기존 연구에서 9개의 산란계수 추정식을 본 자료로 검증하였다. 추정식들 대부분은 결정계수(R²)가 0.79~0.80, RMSE가 0.13~0.15의 범위를 가졌다. 직달·산란 일사량의 농업적 활용을 높이기 위해 본 데이터뿐만 아니라 다양한 자료가 관측되고 공개되어야 할 것이고, 그에 따른 추정식도 정교화될 필요가 있다.

• 태양에너지
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• 제13권2_3호
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• pp.107-119
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• 1993

This paper is to refine the concept of utilizing natural energy, and to introduce new technologies of building energy control. For the global environment protection, it is essential to turn attention to latent capacity of natural renewable energy. Especially the concept of 'Environmental Architecture' is very important from this viewpoint. This paper reviews many of new technologies for environmental architecture developed recently : TIM, high effective solar radiation control strategy of glazing, new passive cooling and heating system etc. The design application of the technology has been introduced.

• 대기
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• 제27권3호
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• pp.331-344
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• 2017

Solar energy is calculated using high-resolution digital elevation model (DEM). In focus on Seoul metropolitan area, correction coefficients of direct and diffuse solar energy with the topographic effect are calculated from DEM with 1720, 900, 450, 90 and 30 spatial resolutions ($m{\times}m$), respectively. The solar energy on the real surface with high-resolution is corrected using by the correction coefficients with topographic effect from the solar energy on horizontal surface with lower resolution. Consequently, the solar energy on the real surface is more detailed distribution than those of horizontal surface. In particular, the topographic effect in the winter is larger than summer because of larger solar zenith angle in winter. In Seoul metropolitan area, the monthly mean topographic effects are more than 200% in winter and within 40% in summer. And annual topographic effects are negative role with more than -60% and positive role with below 40%, respectively. As a result, topographic effect on real surface is not a negligible factor when calculating and analyzing solar energy using regional and global models.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.63-67
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• 2011

KnowledgThe Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at different locations. Because of a poor reliability of existing data, KIER's new data will be extensively used by the solar system users as well as by research institutes. But the quality of solar insolation data is not always good. This reports on an attempt to identify systematic error in such data using clear-day analysis for data rehabilitation. Clear-day analysis is successful in uncovering solar insolation data of questionable quality. It is not proven that rehabilitation process can improve the quality of data for daily or monthly means, but it is suggested that the method can be used to improve the quality of data for monthly means of several years for use in many applications of solar energy plarming. Earlier studies finding a maximum ETR of about 0.80 are confirmed.

• 한국강구조학회 논문집
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• 제9권3호통권32호
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• pp.431-440
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• 1997

본 논문에서는 교량 단면 내의 시간 종속적 온도 분포를 결정하기 위해, 기존의 열 전달 이론 및 태양 에너지 전달에 대한 이론을 바탕으로 기상관측소 및 현장에서 측정한 기상 자료로부터 교량 온도의 예측에 관한 이론적 모델에 대해 기술하였다. 특히 이 모텔에서는 주간에 교량의 온도 상승에 지배적인 영향을 미치는 태양일사(solar radiation)에 대해 태양 에너지 관련 분야의 여러 실험적 연구 결과를 바탕으로 태양일사량의 계산에 대해 기존에 연구되어 있는 식들 중에서 가장 적합한 식을 제시하였다. 이 해석 모델의 타당성은 사당 고가차도의 장기 계측된 온도 측정 결과와 비교 검토되었다. 또한 장기간 측정된 온도 결과로부터 교량 온도 예측에 대한 해석적 기준(analytical criteria)을 제시하기 위해, 교량의 축 방향 신축의 원인이 되는 단면평균온도, 그리고 곡률 변형을 유발하는 단면온도차 등 교량 단면의 온도 분포와 관련된 변수들과 대기온도, 일사량 등 기상 자료와 관련된 변수들 간의 선형 상관관계(linear correlation)에 대해 기술하였다.

• Ocean and Polar Research
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• 제26권3호
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• pp.439-451
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• 2004

Total solar irradiance (750), total UV irradiunce (TUV) and erythemal UV irradiance (EUV) measured at King Sejong station $(62.22^{\circ}S,\;58.78^{\circ}W)$ in west Antarctica have been used together with total ozone, cloud amount and snow cover to examine the effects of ozone, cloud and snow surface on these surface solar inadiunce over the period of 1998-2003. The data of three solar components for each scan were grouped by cloud amount, n in oktas $(0{\leq}n<3,\;3{\leq}n<4,\;4{\leq}n<5,\;5{\leq}n<6,\;6{\leq}n<7\;and\;7{\leq}n<8)$ and plotted against solar zenith angle (SZA) over the range of $45^{\circ}\;to\;75^{\circ}$. The radiation amplification factor (RAE) is used to quantify ozone effect on EUV. RAF of EUV decreases from 1.51 to 0.94 under clear skies but increases from 0.94 to 1.85 under cloudy skies as SZA increases, and decreases from 1.51 to 1.01 as cloud amount increases. The effects of cloud amount and snow surface on EUV are estimated as a function of SZA and cloud amount after normalization of the data to the reference total ozone of 300 DU. In order to analyse the transmission of solar radiation by cloud, regression analyses have been performed for the maximum values of solar irradiance on clear sky conditions $(0{\leq}n<3)$ and the mean values on cloudy conditions, respectively. The maximum regression values for the clear sky cases were taken to represent minimum aerosol conditions fur the site and thus appropriate for use as a normalization (reference) factor for the other regressions. The overall features for the transmission of the three solar components show a relatively high values around SZAs of $55^{\circ}\;and\;60^{\circ}$ under all sky conditions and cloud amounts $4{\leq}n<5$ and $5{\leq}n<6$. The transmission is, in general, the largest in TUV and the smallest in EUV among the three components of the solar irradiance. If the ground is covered with snow on partly cloudy days $(6{\leq}n<7)$, EUV increases by 20 to 26% compared to snow-free surface around SZA $60^{\circ}-65^{\circ}$, due to multiple reflections and scattering between the surface and the clouds. The relative difference between snow surface and snow-free surface slowly increases from 9% to 20% as total ozone increases from 100 DU to 400 DU under partly cloud conditions $(3{\leq}n<6)$ at SZA $60^{\circ}$. The snow effects on TUV and TSO are relatively high with 32% and 34%, respectively, under clear sky conditions, while the effects changes to 36% and 20% for TUV and TSO, respectively, as cloud amount increases.

• 전력전자학회논문지
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• 제26권1호
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• pp.38-45
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• 2021

The photovoltaic module has the characteristic of changing its output characteristics depending on the amount of radiation and temperature, where the arrays that connect them in series and parallel also have the same characteristics. These characteristics require the MPPT technique to find the maximum power point. Existing P&O and IncCond cannot find the global maximum power point (GMPP) for partial shading. Moreover, in the case of Improved-GMPPT and Enhanced Search-Skip-Judge-GMPPT, GMPP due to partial shading can be found, but the variation in the open voltage during temperature fluctuations will affect the operation of the Skip and will not be able to perform accurate MPPT operation. In this study, we analyzed the correlation between voltage, current, and power under solar module and array conditions. We also proposed a technique to find the maximum power point even for temperature fluctuations using not only the amount of radiation but also the temperature coefficient. The proposed control technique was verified through simulations and experiments by constructing a 2.5 kW single-phase solar power generation system.

• 한국태양에너지학회 논문집
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• 제30권3호
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• pp.108-115
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• 2010

Global warming and heat island make the outdoor air temperature ascend. Tall office buildings are covered with glass window facades as a design aspect and the portion of window area to facade area is increasing. Hence, cooling load for solar radiation passing through glass window is rising. Cooling air to a certain room is supplied equally despite the face of the room in most office buildings. Especially, the west part of the office cannot maintain the required temperature that occupant needs because of the solar heat coming through windows.?In this study, we projected the water spray system to reduce the solar heat transfer and to reflect the solar ray through windows. We perform the experiments to evaluate the performance of the solar heat protection devices. We measured the room temperature of two separated office rooms for solar heat control devices. The investigation's results show that the water spray system is sufficient to the coated glass and the venetian blinds for the decrease of the solar heat inflow.

• 한국측량학회지
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• 제33권5호
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• pp.415-426
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• 2015

구름의 영향 없이 지표면에 도달하는 일사량을 추정하는 것은 일사량 자원지도의 궁극적인 목표이며, 이는 청천일 모델(clear sky model)을 사용하여 이론적으로 추정할 수 있다. 일사량 지도의 정확도는 청천일 모델의 정확도와 연결되기 때문에 연구목적과 연구지역에 적합한 청천일 모델을 선정하고 분석하는 것은 매우 중요하다. 본 연구에서는 대기혼탁 인자를 사용하여 일사량을 추정하는 고차원 모델(ESRA, Dumortier, MODTRAN)과 태양고도를 변수를 하는 일차원 모델(Bourges, PdBV)을 사용하여 한반도의 청천일 일사량을 추정하였으며, 실제 측정 자료와 비교하여 한반도에 적합한 청천일 모델을 분석하고자 하였다. 천리안 기상위성의 가시영상을 사용하여 구름이 없는 청명일을 참조자료로 추출하였으며, RMSE와 MBE를 계산하여 모델별 오차를 분석하였다. 연구결과, Bourges와 PdBV 모델이 실측치와 가장 낮은 RMSE를 가졌으며, PdBV는 계절에 상관없이 비교적 일정한 MBE값을 가졌다. 또한 봄-초여름 기간에 일차원모델은 일사량을 과소 추정하는 경향을 보였으며, 고차원모델은 겨울에 일사량을 과대 추정하는 것으로 나타났다. 추후 모델별로 나타난 오차의 경향 및 계절에 따른 오차를 보정하는 추가 연구를 통하여, 한반도에 최적화된 청천일 일사량 모델을 수정 및 개발할 예정이다.

• 한국측량학회지
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• 제35권1호
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• pp.55-62
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• 2017

The SRP (Solar Radiation Pressure) model has always been an issue in the dynamic GPS (Global Positioning System) orbit determination. The widely used CODE (Center for Orbit Determination in Europe) model and its variants have nine parameters to estimate the solar radiation pressure from the Sun and to absorb the remaining forces. However, these parameters show a very high correlation with each other and, therefore, only several of them are estimated at most of the IGS (International GNSS Service) analysis centers. In this study, we attempted to numerically verify the correlation between the parameters. For this purpose, a bi-directional, multi-step numerical integrator was developed. The correlation between the SRP parameters was analyzed in terms of post-fit residuals of the orbit. The integrated orbit was fitted to the IGS final orbit as external observations. On top of the parametric analysis of the SRP parameters, we also verified the capabilities of orbit prediction at later time epochs. As a secondary criterion for orbit quality, the positional discontinuity of the daily arcs was also analyzed. The resulting post-fit RMSE (Root-Mean-Squared Error) shows a level of 4.8 mm on average and there is no significant difference between block types. Since the once-per-revolution parameters in the Y-axis are highly correlated with those in the B-axis, the periodic terms in the D- and Y-axis are constrained to zero in order to resolve the correlations. The 6-hr predicted orbit based on the previous day yields about 3 cm or less compared to the IGS final orbit for a week, and reaches up to 6 cm for 24 hours (except for one day). The mean positional discontinuity at the boundary of two 1-day arcs is on the level of 1.4 cm for all non-eclipsing satellites. The developed orbit integrator shows a high performance in statistics of RMSE and positional discontinuity, as well as the separations of the dynamic parameters. In further research, additional verification of the reference frame for the estimated orbit using SLR is necessary to confirm the consistency of the orbit frames.