구배형 굴절률 분포에서 반사방지막의 두께 및 굴절률변화인자에 따른 반사율 연구

김창봉(Kim, Chang-Bong) 한국정보기술학회 2021 Proceedings of KIIT Conference Vol.2021 No.11

구배형 굴절률 분포를 갖는 반사방지막에서 구배의 변화율을 결정하는 굴절률분포변화인자(index profile changing parameter)와 코팅 층의 두께는 반사방지막의 반사율을 결정짓는 중요한 요소이다. 본 논문에서는 3층 구조에서 변화인자와 두께를 변화시키면서 반사율을 구하고 분석하였다. 결과로서 변화인자의 값이 커질수록 대체적으로 반사율이 감소함을 알 수 있었다. 그리고 코팅 층의 동일 두께와 동일하지 않은 두께 구조에서는 각 각서로 다른 파장대에서 낮은 반사율을 보였다. The index profile changing parameter and thickness of anti-reflection(AR) coating with graded index are the important factors to determine its reflectance. We simulate and analyze the reflectance of tri layered AR coating by changing the value of profile changing parameter and thickness. The result shows the reflectance decreased according to larger value of profile changing parameter generally. And the reflectance shows the lower value at different wavelength range with different and same thickness case respectively.

Reflectance water index를 이용한 참나무속 3종 낙엽의 함수량 추정

서계홍 ( Kyehong Suh ) 한국환경과학회 2018 한국환경과학회지 Vol.27 No.4

Water status of intact plants has been optically estimated by measuring reflectance at the wavelengths 1,450 nm and 1,900 nm based on their signal strengths. Although another water band at 970 nm is considered to have very small signals, the band apparently lies within the detection range of inexpensive spectrometer and plain charge-coupled device (CCD) camera used in wild fire studies. However measurement of the reflectance at 970 nm has been rarely applied to estimate the water status of dead plant materials such as fallen branch, twig, and leaf. To test the possibility of applying water reflectance at 970 nm to estimate the water content (WC) in leaf litter, the reflectance in various WC values were measured in the leaf litter of three Quercus species (Q aliena, Q aliena, Q mongolica, and Quercus variabilis). The results showed that the WC in the leaf litter can be determined by reflectance water index (WI) in the three Quercus species (WC=1,450×WI-1,378.8, r=0.865). However, there was no interaction effect in the relationship between WI and WC among the litter of the three Quercus species.

항공 초분광 영상을 이용한 광화학반사지수 이용 가능성 평가: 그림자 영향 및 대체 밴드를 중심으로

류재현,신정일,이창석,홍성욱,이양원,조재일,Ryu, Jae-Hyun,Shin, Jung Il,Lee, Chang Suk,Hong, Sungwook,Lee, Yang-Won,Cho, Jaeil 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.5

정규식생지수(NDVI, Normalized Difference Vegetation Index)는 생물량 및 $CO_2$ 흡수량 추정과 병충해 탐지 등 다양한 식생 모니터링 영역에서 활용되고 있다. 그러나, 생물량 탐지에 비해 상대적으로 식생의 생리적 상태 변화에 대한 민감도가 낮아 식생의 생리적 활성 및 스트레스를 파악에 한계가 있다. 최근 개발된 광학반사지수(PRI, Photochemical Reflectance Index)는 식생의 생리적 상태 탐지에 용이한 것으로 알려지고 있으며, 식생의 탄소 흡수량 조사를 위해 향후 발사될 해외의 지구관측위성들의 주요 산출물로 선정되는 등 활용도가 높아질 것으로 전망된다. 이에 다양한 이용에 앞서 광 스트레스에 민감한 PRI 특성을 고려하여 그림자 영향의 해석 방향을 제시하고, 현재 가용한 위성으로 PRI 산출이 가능한지 알아보기 위해 대체 밴드를 평가하였다. 항공 초분광 영상을 이용한 본 연구에서는 PRI값이 그림자 부분에서 광 스트레스의 감소로 인해 증가하였다. 그러나 그림자의 정도가 임계값(Shadow Index<25)을 넘어서면 PRI와 NDVI 모두의 자료 품질이 매우 낮아졌다. 또한, 문헌의 570.0 nm 대신 553.6 nm를 사용하여 산출한 PRI가 오리지널 PRI와 높은 상관관계를 보였으며, RED와 NIR 반사도를 이용하여 다중회귀분석을 수행하였을 때 더욱 향상된 결과를 보였다. 이러한 결과는 향후 식생탐지에서 활용도가 높아질 것으로 기대되는 PRI의 생리적인 의미를 이해하는데 도움이 될 것이다. The applications of NDVI (Normalized Difference Vegetation Index) as a vegetation index has been widely used to understand vegetation biomass and physiological activities. However, NDVI is not suitable way for monitoring vegetation stress because it is less sensitive to change in physiological state than biomass. PRI (Photochemical Reflectance Index) is well developed to present physiological activities of vegetation, particularly high-light-stress condition, and it has been adopted in several satellites to be launched in the future. Thus, the understanding of PRI performance and the development of analysis method will be necessary. This study aims to interpret the characteristics of light-stress-sensitive PRI in shadow areas and to evaluate the PRI calculated by other wavelengths (i.e., 488.9 nm, 553.6 nm, 646.9 nm, and 668.4 nm) instead of 570 nm that used in original PRI. Using airborne-based hyperspectral image, we found that PRI values were increased in shadow detection due to the reduction of high light induced physiological stress. However, the qualities of both PRI and NDVI data were dramatically decreased when the shadow index (SI) exceeded the threshold (SI<25). In addition, the PRI calculated using by 553.6 nm had best correlation with original PRI. This relationship was improved by multiple regression analysis including reflectances of RED and NIR. These results will be helpful to the understanding of physiological meaning on the application of PRI.

태양광 반사율을 이용한 벼 군락의 엽면적지수 추정

이정택,이춘우,주문갑,홍석영 韓國作物學會 1997 한국작물학회지 Vol.42 No.2

태양복사 스펙트럼을 이용하여 벼 군락의 엽면적지수를 비파괴적인 방법으로 추정하고자 1993년 경기도 수원기상대 포장에서 조생종 진부벼와 중만생종 대청벼, 일품벼를 공시하여 벼 군락의 태양광 반사특성과 엽면적지수의 시기별 변화를 조사한 결과는 다음과 같다. 1. 출수이전의 생육기간동안에 태양광의 파장별 반사율은 가시광 파장대에서는 0.1이하로 낮았고, 근적외광 파장대에서는 0.1∼0.5 이상이었다. 가시광 파장대에서는 LAI가 증가할수록 반사율이 감소하였고, 근적외광 파장대는 LAI가 증가할수록 반사율도 증가하였다. 2. 출수전에 근적외광 파장대(720∼1,100nm)의 반사율을 가시광 파장대 (400∼700nm)의 반사율로 나눈 비율이 LAI와 높은 상관을 보였으며, 가시광 파장대중에서는 녹색, 적색파장보다 청색파장(400∼500nm)의 반사율로 나눈 비율이 높은 상관을 보였다. 3. 근적외광 파장의 반사율을 청색파장의 반사율로 나눈 비율중에서 특히 R910/R460 비율이 LAI와 가장 높은 정의 상관을 보였다. 4. 출수이전의 R910/R460과 LAI의 회귀식을 이용한 추정식 Y=0.160799-X0.79776는 실측치와의 상관관계가 매우 높았다. 5. 출수이후엔 근적외광 파장(720∼1,100nm)의 반사율을 적색파장(600∼700nm)의 반사율로 나눈 비율이 청색이나 녹색파장의 반사율로 나눈 것보다 LAI와의 상관이 높았다. To estimate the leaf area index(LAI) of rice plant by non-destructive method, spectral reflectance from rice plant canopy was measured by using the spectroradiometer (LI-1800, LICOR Inc.) with one week interval during the rice growing season at Suwon paddy field in 1993. LAI of two medium late maturing varieties, Daechungbyeo and Ilpumbyeo, and one early maturing variety, Jinbubyeo, were observed and compared with those estimated by vegetation index. The reflectance(R) of visible wavelength remained less than 0.1 over entire growing season, but that of near infrared wavelength remained from 0.1 to 0.5 with the significant positive correlation with LAI. Vegetation index determined by the reflectance of visible against near infrared wavelength showed high correlation with LAI of rice canopy. Vegetation index derived from wide band ratio, NIR(720~1, 100nm) /Blue(400~500nm), showed the highest correlation coefficient with LAI. Vegetation index derived from narrow band(10nm interval) ratio, R910/R460, from transplanting to heading stage corresponded well to measured values (Y=0.16799X-0.79776 ; R2 =0.94). But another vegetation index, NIR(720~1, 100nm) /Red (600~700nm), showed higher correlation with LAI than NIR /Blue did from heading stage to maturity.

Predicting Grain Protein Content of Rice using Remote Sensing Technology

( Tapash Kumar Sarkar ),( Chan-seok Ryu ),( Jeong-gyun Kang ),( Ye-seong Kang ),( Seon-hgeon Kim ),( Sae-rom Jun ),( Won-jun Kim ),( Suk-ku Kim ),( Hyun-jin Kim ) 한국농업기계학회 2016 한국농업기계학회 학술발표논문집 Vol.21 No.2

The ability to estimate and map grain protein content before harvest using remote sensing can help crop growers to set the strategies of harvest and management practices. The objective of the study was to make a prediction model of grain protein content of rice using remote sensing and to test various vegetation indices (normalization) on remote sensing imagery to identify the best vegetation indices for predicting the quality index. Image acquisition was carried out using NIR and RE camera mounted on drone (eBee, senseFly Ltd., Switzerland) on September 11, 2016. Sampling was done synchronously at the geo-referenced points and GPS locations were recorded. Paddy samples were air-dried to 15% moisture content then dehulled and measured the protein and amylose content of the brown rice by grain analyzer (FOSS Infratech^TM 1241 Analyzer, Hoganas, Sweden). Hereafter, each sample was milled to 92% milling yield by a polishing machine and measured the protein and amylose content again. Total images were differentiated into two groups as cloud free and cloud shadowed. On one hand for the cloud free samples; the vegetation index, NDVI derived from the canopy spectral reflectance at green, red and NIR bands, was significantly correlated to the final grain protein content (R2=0.553, RMSE=0.21, n=14) at 99% significant level. On the other hand, for cloud shadowed samples, the result demonstrated that vegetation index, NDVI was significantly correlated to the final grain protein content(R2=0.479, RMSE=0.225, n=35) at 99.9% significant level. Grain protein content of rice can be possibly forecasted using the canopy or images spectral reflectance of Drone at grain filling stage. These models might not be able to directly apply to different ecological conditions, because this study was carried out under the same ecological conditions in the same district. However, use of remote sensing data to predict quality indices such as protein content of grains can be feasible and realized.

Analysis of wave reflection of a stenotic vessel blood pressure wave using the lattice Boltzmann method and impedance boundary condition

Young Woo Kim,김용현,이준상 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

Pressure wave produced by a stenotic vessel was analyzed in terms of the stiffness index, augmentation index and reflection index. An understanding of blood pressure wave reflection is key to developing non-invasive and easy-to-use diagnostic methods. The purpose of this study was to use computational fluid dynamics to analyze blood pressure waves and understand blood pressure wave reflections in stenotic vessels. The lattice Boltzmann method was used with the impedance boundary condition for the blood pressure waves. Variations in blood pressure wave parameters according to different degrees of stenosis were analyzed, in addition to fluid dynamic properties, including flow energy loss. We found that blood pressure wave reflection is related to flow energy loss from stenosis.

스웨디시와 두피반사요법의 연결 마사지가 미세주름·멜라닌·홍반 상태에 미치는 영향

김란,범희주,김한식 한국피부과학연구원 2009 대한피부미용학회지 Vol.7 No.1

The purpose: This study aims to identify the effect of Swedish massage and scalp reflection therapy on micro wrinkles at the outer corners of eyes, melanin index and erythma at the corners of eyes and cheeks. For the study, we compared the conditions of the subjects who had only Swedish massages with those of the subjects who had both the Swedish massage and scalp reflection therapy. The method: We targeted four middle-aged women whose skin was coarse and dry, and had less moist and micro wrinkles and provided both a Swedish massage and a scalp reflection therapy once a week for eight weeks from October 11 to December 4. 2007 for A1 and A2, clinical test groups in a regular basis, focusing on their faces, necks, scalps and decolletee. However, we provided only Swedish massages for the clinical control group, B1 and B2, once a week, focusing on their faces, necks and decolletee. For the scalp reflection therapy, we used fine bamboo poles we designed. To measure wrinkles of the skin, we used objective measuring instruments such as Skin Visiometer (SV600) and Visioscan (VC98) by Courage+Khazaka (C+K electronic GmbH, Cologne, Germany) which measure wrinkles and surface of the skin by a less invasive method, and used Mexameter MX18(Courage and Khazaka, Germany) to measure melanin index(MI) and Erythma index(EI) with a less invasive method. Conclusion: As a result, we found that the test group who had both the Swedish massage and scalp reflection therapy had considerably less wrinkles at the corners of eyes, and showed stable reduction of melanin index and erythma index. 두피반사요법과 스웨디시 마사지를 연결하여 피부 관리한 임상 대상자와 스웨디시 마사지만 실시하여 피부 관리한 임상 대상자의 안면 눈 꼬리부위 미세주름 상태와 눈 꼬리부위 및 볼 부위의 멜라닌지수, 홍반지수 변화에 미치는 영향에 대하여 알아보고자 임상관찰하여 연구하였다. 피부가 거칠고 잔주름이 관찰되며 보습력이 떨어진 건성피부유형의 40대 중년여성 4명을 선정하여 임상 시험군 A1, A2를 2007년 10월 11일부터 2007년 12월 4일까지 8주 동안 규칙적으로 주1회 스웨디시 마사지와 두피반사요법을 연결하여 안면, 목, 데콜테, 두피부분까지 피부 관리하였으며, 임상시험 대조군 B1, B2는 규칙적으로 동기간에 주1회 스웨디시 마사지만을 실시하여 안면과 목, 데콜테 부위까지 피부 관리하였다. 두피반사요법은 대나무를 이용하여 본 연구자가 고안 및 제작한 죽세봉을 사용하였으며, 피부 주름상태 측정은 비 침습적인 방법으로 피부주름을 평가하는 독일의 Courage+Khazaka 회사(C+K electronic GmbH, Cologne, Germany)의 피부주름 및 피부표면 영상분석장비인 Skin Visiometer (SV600), Visioscan (VC98)을 이용하여 피부주름에 대한 객관적인 평가방법의 측정기기로 사용하였으며, Mexameter MX18(Courage and Khazaka, Germany)을 이용하여 비 침습적 방법으로 피부표면의 멜라닌지수(Melanin index, MI)와 홍반지수(Erythema index, EI)를 측정하였다.스웨디시 마사지만 실시한 임상 시험군에 비하여 두피반사요법과 스웨디시 마사지를 연결하여 피부 관리한 임상 시험군이 눈 꼬리부위의 미세주름 감소 효과가 상대적으로 우수하였으며 눈 꼬리 부위 및 볼 부위의 멜라닌지수와 홍반지수도 안정적으로 감소하는 효과를 나타내었다.

간호대학생의 자기성찰과 자아존중감 및 공감능력이 행복지수에 미치는 영향

김지미 ( Kim Jimee ),홍성경 ( Hong Sungkyung ) 경희대학교 동서간호학연구소 2016 동서간호학연구지 Vol.22 No.2

Purpose: The purpose of this study was to explore the levels of self-reflection, self-esteem, and empathy and identify influential factors on happiness index in nursing students. Methods: The data was collected using questionnaires from a convenience sample of 275 nursing students. The data was analyzed with descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and multiple regression. Results: Mean scores of self-esteem, empathy and happiness index were 3.55, 2.89, 3.43, and 66.76, respectively. Self-understanding, self-esteem, and economic status had significant positive effects with a 42% of explained variance of the happiness index. Conclusion: The results suggest that self-understanding, self-esteem, and economic status should be considered as factors when developing intervention strategies to increase the level of the happiness index among nursing students.

PDMS 굴절 조정층이 Mn-Doped SnO₂ (MTO)/Ag/MTO/PDMS/MTO 투명전극의 특성에 미치는 영향

조영수,장건익,Jo, Young-Su,Jang, Gun-Eik 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.6

We fabricated highly flexible Mn-doped $SnO_2$ (MTO)/Ag/MTO/polydimethylsiloxane (PDMS)/MTO multilayer transparent conducting films. To reduce refractive-index mismatching of the MTO/Ag/MTO/polyethylene terephthalate (PET), index-matching layers were inserted between the oxide-metal-oxide-structured films and the PET substrate. The PDMS layer was deposited by spin-coating after adjusting the mixing ratio of PDMS and hexane. We investigated the effects of the index-matching layer on the color and reflectance differences with different PDMS dilution ratios. As the dilution ratio increased from 1:100 to 1:130, the color difference increased slightly, while the reflectance difference decreased from 0.62 to 0.32. The MTO/Ag/MTO/PDMS/MTO film showed a transmittance of 87.18~87.68% at 550 nm. The highest value of the Haacke figure of merit was $47.54{\times}10^{-3}{\Omega}^{-1}$ for the dilution ratio of 1:130.

급격한 광도 변화가 담배 잎에서 반사되는 Normalized Difference Vegetation Index에 미치는 영향

서계홍 ( Kyehong Suh ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.4

Normalized Difference Vegetation Index (NDVI) has played an important role in assessing green plant biomass through remote sensing on global scale since the early 1970s. The concept of NDVI is based on the fact that green plants show higher reflection in near-infrared region than in visible region of the electromagnetic spectrum. However, it is well known that the relocation of chloroplasts in plant leaf cells may dramatically change the optical properties of plant leaves. In this study I traced the changes in the reflectance and transmittance properties of Tobacco leaves at the wavelengths of 660 and 800 nm after a sudden increase in light intensity. The results showed that NDVI of leaves gradually decreased from 72.7% to 69.9% when exposed to a sudden increase in light intensity from 30 to 1,200 μmol/m²·s. This means that the error resulting from the physiological status of the plant should be accounted for a more precise understanding of ground truth corresponding to the data from the remotely acquired images