• 한국지형공간정보학회:학술대회논문집
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• 2002.11a
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• pp.51-57
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• 2002

국내에서 활발하게 연구되고 있는 위성영상을 이용한 원격탐사는 매핑, 환경관리, 시설물 관리 등에 이용되어 왔다. 본 연구에서는 날씨나 태양의 제약을 받지 않는 RADARSAT SAR 영상의 수계지역을 신경망 기법을 이용하여 분류하고자 하였다. RADARSAT은 경사관측을 통하여 영상을 취득하며 지형의 기복에 의한 음영효과(Shadow effect)로 인하여 수계지역 분류시 정확도를 감소시킨다. 이러한 문제를 해결하기 위해서 본 연구에서는 RADARSAT SAR 영상의 역산란계수를 계산하고 음영효과에 의한 분류오류를 감소시키기 위하여 수치고도모형을 사용하였다. 지형의 기복이 작은 평지와 지형의 기복이 심한 산악지로 나누어 연구를 수행하여 각 지역별로 분류 정확도를 평가하였다. 연구결과로 역산란계수를 신경망기법의 단일 입력 자료로 사용한 경우보다 수치고도모형을 같이 사용한 것이 분류 정확도가 높았다. 또한, 수치고도모형을 역산란계수와 함께 입력 자료로 이용할 경우 평지보다 산악지에서 효율적이었다. 산악지역이 많은 국내에서는 SAR영상의 수계지역 추출을 신경망 기법으로 할 경우에는 수치고도모형을 함께 이용함으로써 분류정확도 향상을 시킬 수 있다고 사료된다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.47-54
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• 2009

This research is about the inherent optical properties(IOPs) of algae which is collected from Nam-Hae for basic research of red tide remote sensing technique development. 21 kinds of red tide organisms were cultivated to investigate IOPs of them in the level of laboratory, and specific absorption coefficient of phytoplankton($a^*$) and backscattering coefficient of phytoplankton(${b_b}^*$) are estimated by using spectrophotometer. Absorption spectrums according to species appeared to range from 0.005 to 0.06 ($m^2{\cdot}mg^{-1}$), and the shapes of spectrums were also different. The range of ${b_b}^*$ appeared to be $10^{-2}{\sim}10^{-4}\;m^2{\cdot}mg^{-1}$, which had about 100 times differences between species, and the shape of spectrum have significant difference between species. These results will input as a remote sensing reflectance model input parameter from ocean color.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.187-191
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• 2006

This research is about the optical characteristics of algae which is collected from Nam-Hae for basic research of red tide remote sensing technique development 21 kinds of red tide organisms were cultivated to investigate optical characteristics of them in the level of laboratory, and chlorophyll specific absorption coefficient $(a^*)$ and backscattering coefficient $(b_b^*)$ are estimated by using spectrophotometer. Absorption spectrums according to species appeared to range from 0.005 to 0.06 $(m^2/mg)$, and the shapes of spectrums were also different. The range of $b_b^*$ appeared to be $10^{-2}\sim10^{-4}m^2/mg$, which had about 100 times differences between species, and the shape of spectrum have significant difference between species. These results will input as an ocean color model input parameter from ocean color.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.183-187
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• 2007

적조원격탐사의 기초연구로서 적조생물의 광학적 특성을 조사하였다. 연구에 사용된 적조생물 종은 와편모조류에 속하는 종으로 Scrippsiella trochoidea이다. 광학적 특성 조사를 위해 순수 배양된 생물종을 미세조류은행(KMCC)에서 구입하여 배양하였다. 배양된 샘플로 chlorophyll 농도, 홉광계수(absorption coefficient, a), 소산계수 (attenuation coefficient, c), 역산란계수(backscattering coefficient, $b_b$), 입자크기분포(size distribution, Fd)를 측정하였다. 본 연구의 결과는 2000년 적조 생물종 원격탐사 기술개발 보고서의 결과와 비교해 보았으며, 홉광계수 측정방법에 있어서 filter technique과 부유상태에서 측정한 결과를 비교하였다. 홉광계수에 있어서 기존연구와 본연구의 결과는 매우 유사한 홉광 스펙트럼올 나타내었으며，filter technique와 부유상태에서 측정한 홉광도는 filter technique를 이용한 것이 높은 값을 나타내었다. 이는 multiple absorption, 즉 ${\beta}-effect$에의한 것으로 보인다. 역산란 스펙트럼은 노이즈가 많이 나타났는데 이것은 농도가 충분하지 않아서 나타난 것으로 추정된다. 적조생물의 고유광특성이 해색에 영향을 미칠것이라고 보고 이들 결과는 해색을 재현하기 위한 해색모텔의 입력변수로 활용될 수 있다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2002.10a
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• pp.195-199
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• 2002

SAR(Synthetic Aperture Radar) 영상은 경사촬영을 수행하므로 지형의 기복에 따른 영향을 많이 받는다. 따라서 SAR영상을 이용하여 여러 가지 정보들을 추출하여 이용하기 위해서는 전처리 과정으로서 지형의 기복에 따른 여러 가지 왜곡들을 보정해야 한다. 이에 본 연구에서는 RADARSAT SAR 영상을 이용하여 궤도모델링, 정사보정을 수행하고 역산란계수, 국부입사각 계산 등을 통해 지형기복에 따른 방사왜곡보정을 수행하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.150-158
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• 2003

In the beam pattern synthesis problem using line source, the relationship between source distribution function and beam pattern may be represented by Fourier transform pair. In this paper, a general method to synthesize the line source distribution for a desired lobe-like beam pattern is presented by developing the nonlinear inversion method based on an iterative sampling technique. This method can be applied to the synthesis of continuously distributed dielectric constants satisfying the desired inverse scattering coefficient patterns when illuminating by TE-polarized and TM-polarized plane waves to arbitrary dielectric material. Furthermore this method can also be applied to the synthesis of transmission line with arbitrary reflection coefficient patterns. Some bandstop spatial filter and dispersive transmission line filter are illustrated for generality.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.4
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• pp.89-94
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• 2001

A new design method of the microwave multisection impedance transformer is proposed. This method is based on the inverse scattering theory using the frequency domain reflection coefficient of the transformer to be designed. In the first step, the permittivity profile of a virtual one-dimensional dielectric medium is reconstructed using the desired reflection coefficient. In the second step, the transformer which is equivalent to the reconstructed dielectric medium in view of reflection characteristics is synthesized. Theoretically, this method can be used to design the impedance matching transformers with arbitrary passband characteristics within the limit of the Bode-Fano criteria[1]. Our approach is examined for two design examples to show that it is valid.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.7
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• pp.1139-1146
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• 2001

A tapered impedance-matching line is designed by an inverse scattering method for the one-dimensional medium. The phase compensation factor(PCF) is introduced in order to reduce the error in the inverse scattering process to reconstruct the permittivity profile. By estimating the permittivity profile of the virtual one-dimensional dielectric medium whose reflection characteristic is the same as that of the specified matching line, the matching line is synthesized. The method can be used to design impedance-matching lines with arbitrary passband characteristics without any equivalent circuit analysis. The inevitable errors in the method using the time-domain reflection coefficient can be avoided by using the frequency-domain reflection coefficient.

• Korean Journal of Remote Sensing
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• v.14 no.3
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• pp.285-294
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• 1998

A bio-optic survey was made in the Yellow Sea in May, 1998 for OSMI cal/val and application project. Optical measurements were made in nine stations. From these measurements, apparent and inherent optical properties such as $K_d$, R, a, and $b_b$ were estimated. The patterns of reflectance indicated that all three major constituents, namely, chlorophyll-a, suspended sediments, and CDOM were active in determining the optical properties in the Yellow Sea. Their relative contribution was different among the stations. All the stations had high backscattering and their values fell in Case 2 category. Although the total absorption was very high, it could not be explained by the level of CDOM concentration. It is suggested that the suspended sediment might be highly absorptive and further study is needed to investigate the optical properties of the suspended sediments.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.156-163
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• 2013

In this paper, we propose an algorithm for estimating media characteristics of sea water and subbottom multi-layers. The proposed algorithm for estimating reflection coefficients, uses a transmitted signal and reflected signal obtained from multiple layers of various shape and structure, and the algorithm is called Schur algorithm. The algorithm is efficient in estimating the reflection coefficients since it finds solution by converting the given inverse scattering problem into matrix factorization. To verify the proposed algorithm, we generate a transmit signal and reflected signal obtained from lattice filter model for sea water and subbottom of multi-level non-homogeneous layers, and then find that the proposed algorithm can estimate reflection coefficients efficiently.