• Journal of Korea Water Resources Association
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• v.33 no.4
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• pp.427-435
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• 2000

It is often crucial to obtain a map of flood inundated area with more accurate and rapid manner. This study attempts to evaluate the potential of satellite synthetic aperture radar (SAR) data for mapping of flood inundated area in Imjin river basin. Multitemporal RADARSAT SAR data of three different dates were obtained at the time of flooding on August 4 and before and after the flooding. Once the data sets were geometrically corrected and preprocessed, the temporal characteristics of relative radar backscattering were analyzed. By comparing the radar backscattering of several surface features, it was clear that the flooded rice paddy showed the distinctive temporal pattern of radar response. Flooded rice paddy showed significantly lower radar signal while the normally growing rice paddy show high radar returns, which also could be easily interpreted from the color composite imagery. In addition to delineating the flooded rice fields, the multitemporal radar imagery also allow us to distinguish the afterward condition of once-flooded rice field.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.465-475
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• 2010

Spectral library is a database that archives spectral reflectance and related metadata of earth surface materials. Spectral library plays important role to assist analyzing several types of remote sensor data, to determine suitable wavelength band for detecting a certain material, and to classify hyperspectal image data. This paper describes the structure and content of a spectral library that is suitable for the environment of the Korea peninsula while existing spectral libraries have certain limitations to apply for surface materials covering the region. We designed a spectral library that includes vegetation and man-made materials indigenous to the region. The spectral library also includes spectra of mineral and rock, soil, liquid, and some man-made materials from existing spectral libraries. Newly augmented spectra of vegetation and man-made materials were obtained by spectral measurements in laboratory and field. The spectral library viewer was developed to increase efficiency of usage and searching.

• Geophysics and Geophysical Exploration
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• v.21 no.2
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• pp.94-102
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• 2018

To characterize virtual reflection images of deep subsurface by the method of seismic interferometry, we analyzed effects of offset range, ambient noise, missing data, and statics on interferograms. For the analyses, seismic energy was simulated to be generated by a 5 Hz point source at the surface. Vertical components of particle velocity were computed at 201 sensor locations at 100 m depths of 1 km intervals by the finite difference method. Each pair of synthetic seismic traces was cross-correlated to generate stacked reflection section by the conventional processing method. Wide-angle reflection problems in reflection interferometry can be minimized by setting a maximum offset range. Ambient noise, missing data, and statics turn to yield processing noise that spreads out from virtual sources due to stretch mutes during normal moveout corrections. The level of processing noise is most sensitive to amplitude and duration time of ambient noise in stacked sections but also affected by number of missing data and the amount of statics.

• Korean Journal of Poultry Science
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• v.49 no.2
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• pp.53-60
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• 2022

This study investigated correlations between egg quality indicators to identify external egg quality traits to predict internal egg quality using non-destructive and convenient measurements. Thirteen indicators, including Haugh unit, albumen height, eggshell breaking strength, eggshell thickness, eggshell color (CIE L^*, CIE a^*, CIE b^*), and reflectivity value, egg weight, egg length, egg width, shape index, and yolk color, were investigated. A total of 180 brown eggs were obtained from one 27-week-old flock of Hy-line brown-laying hens raised in a cage system. Correlations were evaluated using Pearson's correlation coefficient (r). The results showed strong correlations between Haugh unit and albumen height, eggshell color CIE L^* and reflectivity, egg weight and width, egg weight and length, eggshell color CIE L^* and CIE a^*, eggshell color CIE a^* and reflectivity, and shape index and egg length (P<0.001). Moderate correlations were observed between eggshell breaking strength and eggshell thickness, eggshell color CIE a^* and CIE b^*, and shape index and egg width (P<0.001). Eggshell color CIE L^* was correlated with eggshell breaking strength (P<0.01), and eggshell color CIE a^* was correlated with Haugh unit, albumen height (P<0.01), and eggshell breaking strength (P<0.001). The present study showed significant correlations between eggshell color and other quality indicators. Thus, this study suggests that eggshell colors based on reflectiveness and the CIE L^*a^*b^* value can be used to estimate the Haugh unit, albumen height, eggshell breaking strength, and thickness.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.1
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• pp.45-55
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• 2016

Light shows various optical behaviors such as reflection, absorption, and scattering on skin for individuals. In particular, reflection of light from the skin has been widely used as the brightness index of the skin of individuals through the measurement of the physical quantity of spectral reflectance. Therefore, the study of light behavior on skin would be useful for the preparation of new evaluation method in the development stage of make-up products. In this study, multi-dimensional analysis for spectral reflectance behavior of light on individual skin was performed using Kubelka-Munk model. Also, we analyzed the contribution of skin parameters such as skin thickness and hemoglobin, which could affect the spectral reflectance, using above model and literature information. Base on this, we calculated the theoretical reflectance of normal women for visual light, which showed good agreement with the measured reflectance. Our study of light propagation in skin based on Kubelka-Munk model provides useful insight for the development of personalized cosmetic in the near future.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.6
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• pp.679-689
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• 2014

In this paper, an analysis of the effect of time-variant reflected impedance and its detection method on wireless power transfer(WPT) systems are presented. The reflected resistance at WPT systems is very important parameter as it indicates how well matched antenna is and will exhibit high efficiency. Proposed detection method is based on transmitter current variation analysis with respect to frequency sweep. Using the proposed design method, a wireless power transfer system operating at the frequency of 125 kHz, is design and detect reflected impedance variation. The proposed design method provides good agreements between measured and simulated results. Therefore, The proposed detecting method provides a nonintrusive method to detect harmful object in WPT system.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.900-903
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• 2012

현대사회의 의료 시술 중 부작용이 거의 없으며 배우기 쉬워 일상적으로 널리 사용되고 있는 의료형태를 대체의학이라 한다. 많은 선진국에서 미래형 의료 서비스로 대체의학에 관한 연구를 활발히 진행하고 있다. 대체의학은 종류가 많지만 그 중 귀에 몸의 각 부위가 상응하는 반사점이 있으며 이를 자극하여 치료하는 형태를 이침요법(耳針療法)이라 한다. 본 논문에서는 이러한 이침요법(耳針療法)을 사용하여 폐에 상응하는 이혈 반사점을 자극하였을 때 음성의 변화를 분석하는 실험을 수행하였다. 이를 위해 폐 이혈(耳穴) 자극 전과 후의 음성을 수집하고 기존 연구를 기반으로 폐와 연관성이 있는 음성분석 요소인 발화속도, Intensity 기술을 적용하여 변화 지표를 측정하고 이를 분석하여 이혈요법의 효과를 입증하는 연구를 수행하였다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2010.06a
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• pp.117-118
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• 2010

위성 주사 및 촬영자료는 지표면의 반사광을 다중분광 형태로 주사하여 기록된다. 그리나 각 밴드에 기록된 지표복사체의 반사치는 피복체의 분광특성만을 나타내기 보다는 태양고도 및 방위, 그리고 지형 등에 따른 방향성 영향이 포함되기 때문에 산림의 관리 및 이용을 위한 기초자료로 식생지수를 추정할 때에 오차의 범위를 넘어 오류가 발생한다. 따라서 동일 방향성 조건의 수종에 따른 고유 정규식생지수(Normalized Difference Vegetation Index, 이하 NDVI) 값을 구하기 위해서는 지형효과에 대한 보정이 필요하다. 본 연구에서는 QuickBird 다중분광(MS)자료 기반의 NDVI값을 사면향별로 분석하여 산림 NDVI의 방향성을 증명하였다.

• KIEAE Journal
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• v.7 no.3
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• pp.63-70
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• 2007

It is known that early reflections, their energy and delay times after the arrival of direct sound are important factors for speech intelligibility. In this basis, acoustical parameters like D50 and C80 had been proposed and are widely used for assessing the listening condition of rooms. These parameters are focused on the fraction of the early energy to the total, regardless of the spatial characteristics of the early reflections. This means that all the early reflections, arrived in certain time boundary. from front, behind, down and upside have the same impact on speech intelligibility. From the questionable simplicity, the influence of the direction of early reflections on speech intelligibility is examined in this study. A computer simulation speech intelligibility test, conducted for 22 university students, found that the reflection of vertical direction with method of the Paired comparison also the preference of 0.746 degree was visible an increase.

• Korean Journal of Remote Sensing
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• v.35 no.6_2
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• pp.1149-1160
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• 2019

In this study, two radiometric correction methods deriving reflectance from UAV multispectral image for monitoring forest vegetation were applied and evaluated. Multispectral images were obtained from a small multispectral camera having 5 spectral bands. Reflectance were derived by applying the two methods: (1) the direct method using downwelling irradiance measurement and (2) the empirical line correction method by linking a set of field reflectance measured simultaneous with the image capture. Field reflectance were obtained using a spectroradiometer during the flight and used for building the linear equation for the empirical method and for the validation of image reflectance derived. Although both methods provided the high correlations between field reflectance and image-derived reflectance, their distributions were somewhat different. While the direct method provided rather stable and consistent distribution of reflectance all over the entire image area, the empirical method showed very unstable and inconsistent reflectance distribution. The direct method would be more appropriate for relatively wide area that requires more time to acquire image and may vary in downwelling irradiance and atmospheric conditions.