• 대한원격탐사학회지
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• 제24권5호
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• pp.427-436
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• 2008

This paper presents radar remote sensing of soil moisture and surface roughness for vegetated surfaces. A precise volume scattering model for a vegetated surface is derived based on the first-order radiative transfer technique. At first, the scattering mechanisms of the scattering model are analyzed for various conditions of the vegetation canopies. Then, the scattering model is simplified step by step for developing an appropriate inversion algorithm. For verifying the scattering model and the inversion algorithm, the polarimetric backscattering coefficients at 1.85 GHz, as well as the ground truth data, of a tall-grass field are measured for various soil moisture conditions. The genetic algorithm is employed in the inversion algorithm for retrieving soil moisture and surface roughness from the radar measurements. It is found that the scattering model agrees quite well with the measurements. It is also found that the retrieved soil moisture and surface roughness parameters agree well with the field-measured ground truth data.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1711-1714
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• 2006

Anchoring energy of liquid crystals on solid substrates is a key parameter in liquid crystal technology. A nonperturbative method of its measurement by dynamic light scattering on thermal orientational fluctuations is presented, The ratio of the zenithal and azimuthal anchoring coefficients is shown to be equal to the ratio of the orientational elastic constants.

• 한국광학회지
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• 제25권1호
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• pp.1-7
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• 2014

구름에서의 다중산란 효과는 Mie 산란현상을 이용하는 탄성산란 라이다에서 그 해를 구하는데 있어서, 매우 중요한 오차요인으로 작용하기 때문에 이 효과를 보정하는 것은 그 자체만으로도 매우 중요하다. 이를 위하여 구름에서 다중산란되는 현상을 Monte Carlo 방법으로 계산하였으며, 이 결과를 적용하여 물방울 구름의 총량과 유효입자크기를 추출하는 방법을 제안하였다. 구름의 유효입자 크기가 $2.5{\mu}m$ 이하일 경우엔 355 nm나 1064 nm에서 얻은 두 파장의 소광계수로 쉽게 그 값들을 구할 수 있음을 알 수 있었다. 크기가 큰 경우엔 라이다 신호의 안정화된 선형편광도가 유효입자크기, 총량, 그리고 소광계수와 관련이 있음을 알 수 있었으며, 이 관계를 통하여 큰 입자의 경우에도 라만 라이다와 편광 라이다를 이용한다면 유효입자크기와 총량을 구할 수 있다는 것을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.979-982
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• 2007

The effect of a scattering wall surfaces on sound diffusion can be assessed by determining the scattering and diffusion coefficients in the laboratory. However, the sound field in a concert hall including scattered reflections is different from the laboratory measurement condition. Therefore, there is a need for objective investigation of diffusion in real sound fields. In this paper, possible acoustical parameters of in-situ measurements are discussed.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2001년도 종합학술발표회 논문집 Vol.11 No.1
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• pp.332-336
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• 2001

The new RST is recently developed by the product expansion of the scattering functions in the field of acoustics. The new formulation suggests that the scattering coefficients consist of resonance, non-resonance, and their interactional components. In the scattering problems of acoustic waves, the moduli and phase of the resonance coefficient are obtained the appropriate results through the new RST. In our recent works the new RST was successfully applied to the scattering problem of electromagnetic waves for coated conducting cylinder and sphere. In this paper, the new RST is applied to the 2-dimensional scattering problem of electromagnetic waves for a homogeneous dielectric cylinder, and the numerical results are compared with the previous RST.

• Current Optics and Photonics
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• 제5권3호
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• pp.278-288
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• 2021

We propose a characterization method for the scattering property of microspheres using spectroscopic optical coherence tomography (OCT). To prove the effectiveness of the proposed method, we prepare solutions of different concentrations using microspheres ranging from 28 to 2300 nm in diameter. Time-frequency analysis is performed on the measured interference spectrum of each solution, and the resulting spectroscopic information is converted into histograms for centroid wavelengths. The histograms present a very sensitive response to changes in the concentration and size of microspheres. We classify them into three categories according to their characteristics. When the histogram of each category is replaced with the corresponding calculated value of the scattering coefficient, each category is mapped to a different scattering-coefficient region. It is expected that the proposed method could be used to investigate the optical characteristics of a biological sample from OCT images, which would be helpful for optical diagnostic and therapeutic applications.

• 정보통신설비학회논문지
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• 제2권1호
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• pp.63-70
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• 2003

공진산란이론은 산란장의 공진현상을 물리적으로 해석해주는 이론으로, 산란장은 공진성분과 비공진성분 즉 배경성분으로 구성되어 있다고 가정한다. 따라서 공진 성분을 산란장으로부터 추출하기 위해서는 정확한 배경성분을 구하는 과정이 필요한데, 본 연구에서는 원통형 유전체와 공동에 의한 산란장으로부터 공진성분을 얻기 위한 배경성분을 제시하고, 수치 계산을 수행하여 타당성을 확인하였다.

• Journal of electromagnetic engineering and science
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• 제5권2호
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• pp.87-91
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• 2005

This paper presents a Monte-Carlo FDTD technique to determine the scattered field from a perfectly conducting surface like a sea surface, from which the useful information on the incoherent pattern tendency could be observed. A one-dimensional sea surface used to analysis scattering was generated using the Pierson-Moskowitz model. In order to verify the numerical results by this technique, these results are compared with those of the small perturbation method, which show a good match between them. To investigate the incoherent pattern tendency involved, the dependence of the back scattering coefficients on the different wind speed(U) is discussed for the back scattering case.

• 한국전자파학회논문지
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• 제13권1호
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• pp.87-93
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• 2002

기존의 공진산란이론에서는 하나의 모드에 대한 부분파 산란장이 주파수에 대하여 급격히 변하는 공진성분과 서서히 변하는 배경성분의 합으로 이루어졌다고 가정하고 적당한 배경성분을 제거하여 공진성분을 추출했다. 최근에 음향학 분야에서 산란 5-함수의 곱셈전개에 근거를 둔 새로운 공진 산란이론이 개발되어 왔다. 산란장이 공진성분과 배경성분 이외에 이들의 상호간섭성분으로 구성되어 있다고 제안한 이 이론은 공진성분의 크기뿐만 아니라 위상스펙트럼을 정확하게 얻게 해 주었다. 전자기파 분야에서는 유전체로 코팅된 도체 구 혹은 원통의 산란문제에 이 이론이 성공적으로 적용되었다. 본 논문에서는 유전체 실린더의 전자기파의 산란문제로 이 이론을 확장하고 수치계산으로 그 유효성을 검증했다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.324-327
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• 2008

Microwave remote sensing has great potential, especially in monsoon Asia, since optical observations are often hampered by cloudy conditions. The radar backscattering characteristics of rice crop were investigated with a ground-based automatic scatterometer system. The system was installed inside a shelter in an experimental paddy field at the National Institute of Agricultural Science and Technology (NIAST) before transplanting. The rice cultivar was a kind of Japonica type, called Chuchung. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables, and a personal computer that controls frequency, polarization and data storage. This system automatically measures fully-polarimatric backscattering coefficients of rice crop every 10 minutes, accompanied by a digital camera that takes pictures in a fixed position with the same interval. The backscattering coefficients were calculated by applying a radar equation. Plant variables, such as leaf area index (LAI), biomass, plant height and weather conditions were measured periodically throughout the rice growth season. We have performed polarimetric decomposition of paddy data such as single, double and volume scattering to extract the scattering information effectively. We investigated the relationships between backscattering coefficients and the plant variables.