• Journal of Astronomy and Space Sciences
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• 제11권1호
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• pp.1-12
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• 1994

The structure of the magnetic funnel element in the intermediate polar is considered in terms of an important site for the X-ray absorption and the reemission of the X-ray as the optical light. In this paper the column density and the optical depth vary with the filling factor, which is introduced to characterize the structure of matter in the magnetic funnel element. The results of the energy dependence of the X-ray spectrum and the modulation depth of the X-ray light curve are discussed.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 동계학술발표회 논문집
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• pp.72-73
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• 2007

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.298-299
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• 2005

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 동계학술발표회 논문집
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• pp.331-332
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• 2008

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.221-222
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• 2008

• 한국안광학회지
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• 제12권3호
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• pp.121-124
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• 2007

각막굴절교정절제술에서 각막의 절제 깊이를 Munnerlyn 식을 유도하여 계산하였다. 계산은 4 mm에서 8 mm 사이의 광학 직경과 -1 Dptr에서 -12 Dptr 사이의 교정굴절력에 대해 수행되었다. 계산결과는 Munnerlyn 근사식과 비교될 수 있는데, 낮은 교정굴절력에서는 두 식간에 오차가 없었으나, 6 Dptr 이상의 교정굴절력에서 1 Dptr의 오차가 발생하였다. 하지만 이러한 오차는 기하학적 가정에 근거한 수학적 모델에 의한 계산결과이며, 수술환경의 오차와도 비교되어야 한다.

• 대한원격탐사학회지
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• 제29권6호
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• pp.601-610
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• 2013

As a standard water clarity variable, the vertical underwater visibility, called Secchi depth, is estimated with ocean color satellite data. In the present study, Moderate Resolvtion Imaging Spectradiometer (MODIS) data are used to measure the Secchi depth which is a useful indicator of ocean transparency for estimating the water quality and productivity. To estimate the Secchi depth $Z_v$, the empirical regression model is developed based on the satellite optical data and in-situ data. In the previous study, a semi-analytical algorithm for estimating $Z_v$ was developed and validated for Case 1 and 2 waters in both coastal and oceanic waters using extensive sets of satellite and in-situ data. The algorithm uses the vertical diffuse attenuation coefficient, $K_d$($m^{-1}$) and the beam attenuation coefficient, c($m^{-1}$) obtained from satellite ocean color data to estimate $Z_v$. In this study, the semi-analytical algorithm is validated using temporal MODIS data and in-situ data over the Yellow, Southern and East Seas including Case 1 and 2 waters. Using total 156 matching data, MODIS $Z_v$ data showed about 3.6m RMSE value and 1.7m bias value. The $Z_v$ values of the East Sea and Southern Sea showed higher RMSE than the Yellow Sea. Although the semi-analytical algorithm used the fixed coupling constant (= 6.0) transformed from Inherent Optical Properties (IOP) and Apparent Optical Properties (AOP) to Secchi depth, various coupling constants are needed for different sea types and water depth for the optimum estimation of $Z_v$.

• 한국음향학회지
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• 제42권1호
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• pp.67-74
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• 2023

발성하고 있는 입 주변에서 취득한 영상은 발성 음에 따라 특이적인 패턴을 나타낸다. 이를 이용하여 화자의 얼굴 하단에서 취득한 영상으로부터 발성 음을 인식하거나 합성하는 방법이 제안되고 있다. 본 연구에서는 심도 영상을 협력적으로 이용하는 영상 기반 음성합성 기법을 제안하였다. 심도 영상은 광학 영상에서는 관찰되지 않는 깊이 정보의 취득이 가능하기 때문에 평면적인 광학 영상을 보완하는 목적으로 사용이 가능하다. 본 논문에서는 음성 합성 관점에서 심도 영상의 유용성을 평가하고자 한다. 60개의 한국어 고립어 음성에 대해 검증 실험을 수행하였으며, 실험결과 객관적, 주관적 평가에서 광학적 영상과 근접한 성능을 얻는 것을 확인할 수 있었으며 두 영상을 조합하여 사용하는 경우 각 영상을 단독으로 사용하는 경우보다 향상된 성능을 나타내었다.

• 천문학회지
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• 제48권1호
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• pp.57-66
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• 2015

Monte-Carlo radiative models of the diffuse Galactic light (DGL) in our Galaxy are calculated using the dust radiative transfer code MoCafe, which is three-dimensional and takes full account of multiple scattering. The code is recently updated to use a fast voxel traversal algorithm, which has dramatically increased the computing speed. The radiative transfer models are calculated with the generally accepted dust scale-height of 0.1 kpc. The stellar scale-heights are assumed to be 0.1 or 0.35 kpc, appropriate for far-ultraviolet (FUV) and optical wavelengths, respectively. The face-on optical depth, measured perpendicular to the Galactic plane, is also varied from 0.2 to 0.6, suitable to the optical to FUV wavelengths, respectively. We find that the DGL at high Galactic latitudes is mostly due to backward or large-angle scattering of starlight originating from the local stars within a radial distance of r < 0.5 kpc from the Earth. On the other hand, the DGL measured in the Galactic plane is mostly due to stars at a distance range that corresponds to an optical depth of $${\sim_\sim}$$ 1 measured from the Earth. Therefore, the low-latitude DGL at the FUV wavelength band would be mostly caused by the stars located at a distance of $r{\leq}0.5$ kpc and the optical DGL near the Galactic plane mainly originates from stars within a distance range of $1{\leq}r{\leq}2kpc$. We also calculate the radiative transfer models in a clumpy two-phase medium. The clumpy two-phase models provide lower intensities at high Galactic latitudes compared to the uniform density models, because of the lower effective optical depth in clumpy media. However, no significant difference in the intensity at the Galactic plane is found.

• Journal of Periodontal and Implant Science
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• 제48권2호
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• pp.84-91
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• 2018

Purpose: The purpose of this study was to visualize and identify peri-implant bone defects in optical coherence tomography (OCT) images and to obtain quantitative measurements of the defect depth. Methods: Dehiscence defects were intentionally formed in porcine mandibles and implants were simultaneously placed without flap elevation. Only the threads of the fixture could be seen at the bone defect site in the OCT images, so the depth of the peri-implant bone defect could be measured through the length of the visible threads. To analyze the reliability of the OCT measurements, the flaps were elevated and the depth of the dehiscence defects was measured with a digital caliper. Results: The average defect depth measured by a digital caliper was $4.88{\pm}1.28mm$, and the corresponding OCT measurement was $5.11{\pm}1.33mm$. Very thin bone areas that were sufficiently transparent in the coronal portion were penetrated by the optical beam in OCT imaging and regarded as bone loss. The intraclass correlation coefficient between the 2 methods was high, with a 95% confidence interval (CI) close to 1. In the Bland-Altman analysis, most measured values were within the threshold of the 95% CI, suggesting close agreement of the OCT measurements with the caliper measurements. Conclusions: OCT images can be used to visualize the peri-implant bone level and to identify bone defects. The potential of quantitative non-invasive measurements of the amount of bone loss was also confirmed.