• 대한원격탐사학회지
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• 제32권6호
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• pp.741-746
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• 2016

알베도는 태양에너지의 흡수량을 결정하는 주요 기후 변수 중 하나로서, 이러한 알베도를 산출하는 것은 기후 변화 연구에 있어 중요한 과정이다. 이 때, 산출된 알베도 자료를 효율적으로 사용하기 위해서는 높은 공간해상도와 장기간의 일관성 있는 산출이 중요하게 고려된다. 따라서 본 연구에서는 Landsat 8을 기반으로 Landsat 7과의 일관성을 유지한 고해상도 지표면 광대역 알베도를 산출하였다. 먼저, Landsat 7과 Landsat 8의 채널 별 일관성을 분석한 결과, 상관계수(R)가 평균 0.96으로 높은 상관성을 보였다. 이러한 결과를 바탕으로 Landsat 7 알베도와 Landsat 8 반사도 채널 자료를 다중회귀분석에 적용하여 Landsat 8 광대역 알베도 전환 식을 도출하였다. 도출된 식을 통해 Landsat 8 지표면 광대역 알베도를 산출하고, Landsat 7 알베도 자료와 비교하여 검증하였다. 그 결과 R-square($R^2$)가 0.89, Root Mean Square Error (RMSE)가 0.003의 높은 정확도를 보였다.

• 한국초지조사료학회지
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• 제29권1호
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• pp.31-36
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• 2009

본 연구는 청예용 사초의 질을 신속하고 정확하게 측정할 수 있는 대안을 모색하기 위하여수행하였다. 근적외선분광분석법을 이용한 사초의 분석가능성을 타진하기 위해 2002년부터 2007년에 거쳐 생산된 각종 사초 258점을 시료로 사용하였다. 즉 시료는 조단백질, 조섬유, NDF, ADF 그리고 건물소화율을 분석하였으며, 또한 NIR System으로 $400{\sim}2,400nm$ 사이의 파장을 얻었다. 그리고 파장과 습식분석치를 이용하여 중회귀식을 만들고 이것을 사용하여 미지의 시료를 분석할 수 있는가를 검증하였다. 근적외선 분석법의 중요한 지표인 결정계수 $r^2$와 표준오차이며 본 실험의 결과 검증식의 $r^2$는 CP(crude protein), CF(crude fiber), ADF (acid detergent fiber), NDF (neutral detergent fiber) 그리고 IVTD(in vitro true digestibility)에서 각 각 0.70, 0.86, 0.94, 0.94 그리고 0.89였다. 검량식은 그 값이 0.47, 0.39, 0.89, 0.90 그리고 0.61이었다. 본 실험 결과 근적외선분광법에 의한 청예사료 질평가가 가능하며 특히 조섬유, ADF 그리고 진정인비트로 소화율 (IVTD)에서 유효할 것으로 나타났다. 그러나 보다 정확한 결과를 얻기 위해서는 시료는 한국사초의 대표성을 갖는 것을 수집하여 사용해야 할 것이다. 앞으로 더 많은 시료를 추가하면 모든 사초를 분석할 강고한 검량식이 작성될 수 있을 것으로 기대된다.

• 한국농림기상학회지
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• 제21권4호
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• pp.261-268
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• 2019

한발 발생이 갈수록 증가하고 있는 가운데, 작물의 생리생화학적 기작과 광합성능을 효율적으로 진단 및 평가 할 수 있는 방법을 찾는 것은 매우 중요한 과제이다. 본 연구를 통해 광화학 반사 지수인 PRI가 콩의 한발 스트레스에 대하여 고온과 고CO₂ 등 미래 기후 변화 환경에서도 유의미한 생육 지표로 활용될 수 있음을 확인하였다. PRI와 대표적 한발 생육지표들(군락 광이용효율, 건물중 변동율, 엽록소 형광, 기공전도도)과의 밀접한 관계를 통해 한발 스트레스 하에서 콩의 광합성 활성과 생장량을 원격으로 모니터링할수 있는 진단 모델 개발의 가능성을 볼 수 있었다. 다만 향후 고온, 고CO₂ 등 기후변화 조건에서 PRI의 성능에 대한 지속적인 평가와 함께 민감도 향상을 위한 광학지표 개발 및 모델 개선 연구가 선행되어야 할 것으로 보인다.

• 한국재료학회지
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• 제21권10호
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• pp.573-579
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• 2011

Highly textured Ag, Al and Al:Si back reflectors for flexible n-i-p silicon thin-film solar cells were prepared on 100-${\mu}m$-thick stainless steel substrates by DC magnetron sputtering and the influence of their surface textures on the light-scattering properties were investigated. The surface texture of the metal back reflectors was influenced by the increased grain size and by the bimodal distribution that arose due to the abnormal grain growth at elevated deposition temperatures. This can be explained by the structure zone model (SZM). With an increase in the deposition temperatures from room temperature to $500^{\circ}C$, the surface roughness of the Al:Si films increased from 11 nm to 95 nm, whereas that of the pure Ag films increased from 6 nm to 47 nm at the same deposition temperature. Although Al:Si back reflectors with larger surface feature dimensions than pure Ag can be fabricated at lower deposition temperatures due to the lower melting point and the Si impurity drag effect, they show poor total and diffuse reflectance, resulting from the low reflectivity and reflection loss on the textured surface. For a further improvement of the light-trapping efficiency in solar cells, a new type of back reflector consisting of Ag/Al:Si bilayer is suggested. The surface morphology and reflectance of this reflector are closely dependent on the Al:Si bottom layer and the Ag top layer. The relationship between the surface topography and the light-scattering properties of the bilayer back reflectors is also reported in this paper.

• 한국초지조사료학회지
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• 제31권4호
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• pp.409-414
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• 2011

본 연구는 춘파용 사초의 사료가치를 신속하고 정확하게 측정할 수 있는 습식분석의 대안을 모색하기 위하여 수행하였다. 근적외선분광 분석법을 이용한 사초의 분석 가능성을 타진하기 위해 2009년에 생산된 사초 175점을 시료로 사용하였다. 시료는 이탈리안 라이그라스와 보리, 그리고 완두를 혼파한 것으로 NIR System으로 400~2,400nm 사이의 파장을 얻었다. 그리고 수분, 조단백질, 조회분, NDF, ADF를 분석한 다음, 파장과 습식분석치를 이용하여 중회귀식을 만들어 미지의 시료를 분석할 수 있는가를 검증하였다. 근적외선 분석법의 중요한 지표는 결정계수 $r^2$와 표준오차이며, 본 실험의 결과에서 검량식의 $r^2$는 수분, CP (crude protein), CA (crude Ash), ADF(acid detergent fiber), NDF (neutral detergent fiber)에서 각각 0.65, 0.97, 0.93, 0.99, 0.97을 보여주었다. 검증식은 그 값이 0.15, 0.94, 0.96, 0.98, 0.98이었다. 본 실험 결과, 근적외선 분광법을 이용한 춘계 파종 조사료의 품질 예측이 가능하며, 수분을 제외한 모든 성분에서 이 방법의 가능성을 보여주었다. 정확도를 높이기 위해서는 대표적인 시료가 검량식개발에 사용되어야 할 것으로 사료되었다.

• 대한원격탐사학회지
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• 제20권5호
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• pp.289-305
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• 2004

Atmospheric correction of Landsat Visible and Near Infrared imagery (VIS/NIR) over aquatic environment is more demanding than over land because the signal from the water column is small and it carries immense information about biogeochemical variables in the ocean. This paper introduces two methods, a modified dark-pixel substraction technique (path--extraction) and our spectral shape matching method (SSMM), for the correction of the atmospheric effects in the Landsat VIS/NIR imagery in relation to the retrieval of meaningful information about the ocean color, especially from Case-2 waters (Morel and Prieur, 1977) around Korean peninsula. The results of these methods are compared with the classical atmospheric correction approaches based on the 6S radiative transfer model and standard SeaWiFS atmospheric algorithm. The atmospheric correction scheme using 6S radiative transfer code assumes a standard atmosphere with constant aerosol loading and a uniform, Lambertian surface, while the path-extraction assumes that the total radiance (L/sub TOA/) of a pixel of the black ocean (referred by Antoine and Morel, 1999) in a given image is considered as the path signal, which remains constant over, at least, the sub scene of Landsat VIS/NIR imagery. The assumption of SSMM is nearly similar, but it extracts the path signal from the L/sub TOA/ by matching-up the in-situ data of water-leaving radiance, for typical clear and turbid waters, and extrapolate it to be the spatially homogeneous contribution of the scattered signal after complex interaction of light with atmospheric aerosols and Raleigh particles, and direct reflection of light on the sea surface. The overall shape and magnitude of radiance or reflectance spectra of the atmospherically corrected Landsat VIS/NIR imagery by SSMM appears to have good agreement with the in-situ spectra collected for clear and turbid waters, while path-extraction over turbid waters though often reproduces in-situ spectra, but yields significant errors for clear waters due to the invalid assumption of zero water-leaving radiance for the black ocean pixels. Because of the standard atmosphere with constant aerosols and models adopted in 6S radiative transfer code, a large error is possible between the retrieved and in-situ spectra. The efficiency of spectral shape matching has also been explored, using SeaWiFS imagery for turbid waters and compared with that of the standard SeaWiFS atmospheric correction algorithm, which falls in highly turbid waters, due to the assumption that values of water-leaving radiance in the two NIR bands are negligible to enable retrieval of aerosol reflectance in the correction of ocean color imagery. Validation suggests that accurate the retrieval of water-leaving radiance is not feasible with the invalid assumption of the classical algorithms, but is feasible with SSMM.

• 대한원격탐사학회지
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• 제38권6_1호
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• pp.1385-1394
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• 2022

본 연구에서는 MODerate resolution Imaging Spectroradiometer (MODIS) 자료를 활용하여 20년(2002-2021)의 중분류 토지피복별 알베도 변화를 분석하고, Visible Infrared Imaging Radiometer Suite (VIIRS)의 10년(2012-2021) 자료를 활용해 MODIS 자료와의 차이를 분석하였다. MODIS와 VIIRS의 알베도 자료는 Bidirectional Reflectance Distribution Function (BRDF) 모델을 활용해 생산된 Sinusoidal Tile Grid 기반 500 m 공간해상도의 일단위 알베도 자료 MCD43A3와 VNP43IA3를 우리나라 범위에 대하여 구축하였다. Python 3.9 기반으로 작성된 코드를 활용하여 Reprojection을 하였으며, Resampling method는 Nearest neighbor를 적용하였다. 알베도 분석에는 단파 영역(Shortwave)의 White sky albedo와 Black sky albedo를 활용하였다. MODIS 자료를 활용한 20년의 알베도 분석 결과, 모든 토지이용에서 알베도가 상승하는 경향이 나타났다. 2000년대(2002-2011)에 비해 2010년대(2012-2021)의 평균 알베도가 산림 지역에서 0.0027의 가장 큰 상승값을 보였고, 그 다음으로 초지가 0.0024의 상승값을 보였다. VIIRS와 MODIS의 알베도를 비교한 결과, VIIRS의 알베도가 0.001에서 0.1 만큼 더 큰 것으로 나타났으며, 이는 영상의 촬영시기에 따른 지표면 반사도와 센서의 특성 차이에 의한 것으로 판단된다.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1246-1246
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• 2001

The quality of meat is highly variable in many properties. This variability originates from both animal production and meat processing. At the pre-slaughter stage, animal factors such as breed, sex, age contribute to this variability. Environmental factors include feeding, rearing, transport and conditions just before slaughter (Hildrum et al., 1995). Meat can be presented in a variety of forms, each offering different opportunities for adulteration and contamination. This has imposed great pressure on the food manufacturing industry to guarantee the safety of meat. Tissue and muscle speciation of flesh foods, as well as speciation of animal derived by-products fed to all classes of domestic animals, are now perhaps the most important uncertainty which the food industry must resolve to allay consumer concern. Recently, there is a demand for rapid and low cost methods of direct quality measurements in both food and food ingredients (including high performance liquid chromatography (HPLC), thin layer chromatography (TLC), enzymatic and inmunological tests (e.g. ELISA test) and physical tests) to establish their authenticity and hence guarantee the quality of products manufactured for consumers (Holland et al., 1998). The use of Near Infrared Reflectance Spectroscopy (NIRS) for the rapid, precise and non-destructive analysis of a wide range of organic materials has been comprehensively documented (Osborne et at., 1993). Most of the established methods have involved the development of NIRS calibrations for the quantitative prediction of composition in meat (Ben-Gera and Norris, 1968; Lanza, 1983; Clark and Short, 1994). This was a rational strategy to pursue during the initial stages of its application, given the type of equipment available, the state of development of the emerging discipline of chemometrics and the overwhelming commercial interest in solving such problems (Downey, 1994). One of the advantages of NIRS technology is not only to assess chemical structures through the analysis of the molecular bonds in the near infrared spectrum, but also to build an optical model characteristic of the sample which behaves like the “finger print” of the sample. This opens the possibility of using spectra to determine complex attributes of organic structures, which are related to molecular chromophores, organoleptic scores and sensory characteristics (Hildrum et al., 1994, 1995; Park et al., 1998). In addition, the application of statistical packages like principal component or discriminant analysis provides the possibility to understand the optical properties of the sample and make a classification without the chemical information. The objectives of this present work were: (1) to examine two methods of sample presentation to the instrument (intact and minced) and (2) to explore the use of principal component analysis (PCA) and Soft Independent Modelling of class Analogy (SIMCA) to classify muscles by quality attributes. Seventy-eight (n: 78) beef muscles (m. longissimus dorsi) from Hereford breed of cattle were used. The samples were scanned in a NIRS monochromator instrument (NIR Systems 6500, Silver Spring, MD, USA) in reflectance mode (log 1/R). Both intact and minced presentation to the instrument were explored. Qualitative analysis of optical information through PCA and SIMCA analysis showed differences in muscles resulting from two different feeding systems.

• Applied Microscopy
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• 제47권3호
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• pp.131-147
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• 2017

In this work further optical and electrical investigations of pure and Zr doped $Mn_3O_4$ (from 0 up to 20 at.%) thin films as a function of frequency. First, the refractive index, the extinction coefficient and the dielectric constants in terms of Zr content are reached from transmittance and reflectance data. The dispersion of the refractive index is discussed by means of Cauchy model and Wemple and DiDomenico single oscillator models. By exploiting these results, it was possible to estimate the plasma pulse ${\omega}_p$, the relaxation time ${\tau}$ and the dielectric constant ${\varepsilon}_{\infty}$. Second, we have performed original ac and dc conductivity studies inspired from Jonscher model and Arrhenius law. These studies helped establishing significant correlation between temperature, activation energy and Zr content. From the spectroscopy impedance analysis, we investigated the frequency relaxation phenomenon and hopping mechanisms of such thin films. Moreover, a special emphasis has been putted on the effect of the oxidation in air of hausmannite thin films to form $Mn_2O_3$ ones at $350^{\circ}C$. This intrigue phenomenon which occurred at such temperature is discussed along with this electrical study. Finally, all results have been discussed in terms of the thermal activation energies which were determined with two methods for both undoped and Zr doped $Mn_3O_4$ thin films in two temperature ranges.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1614-1614
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• 2001

The sweetness (。Bix) of fruit is the main quality factor contributing to the fruit taste. The brix of the apple fruit can be measured non-destructively by near infrared (NIR) spectroscopy, allowing the sweetness grading of individual apple fruit. However, the fruit quality is influenced by various factors such as growing location, producing year, variety and harvest time etc., accordingly the robust NIR calibration is required. In this experimental results are presented the influence of two variations such as growing location and producing year of apple fruit in establishing of calibrations for sweetness, and developed a stable and highly accurate calibration. Apple fruit (Fuji) was collected every year from 1995 to 1997 in 3 different growing locations (Andong, Youngchun and Chungsong) of Kyungpook in Korea. NIR reflectance spectra of apple fruit were scanned in wavelength range of 1100∼2500nm using an InfraAlyzer 500C (Bran+Luebbe) with halogen lamp and PbS detector. The multiple linear regression and stepwise was carried out between the NIR raw spectra and the brix measured by refractometer to select the best regression equations. The calibration models by each growing district were well predicted to dependent sample set, but poorly predicted to independent sample set. Combined calibration model using data of three growing districts predicted reasonable well to a population set drawn from all growing districts(SEP = 0.69%, Bias=-0.075). The calibration models by each harvest year were not transferable across harvest year, however a combined calibration model using data of three harvest years was sufficiently robust to predict each sample sets(SEP = 0.53%, Bias = 0.004).