• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.137-140
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• 1999

본 논문에서는 디지털 보청기의 자동보정법을 제안하고 이를 이용하여 구현한 보정시스템에 대하여 기술한다. 일반적으로 난청환자의 청각 손실은 전 주파수를 걸쳐 일정하게 발생하는 것이 아니라, 고음 또는 저음 등 일부 특정 주파수 대역의 청각특성의 이득이 다른 주파수에 비해 상대적으로 낮아져서 생기는 현상이다. 그러나 현재까지의 보청기는 이와 같은 청각 손실을 가지고 있는 환자들에 대하여 전 주파수 대역의 음압을 동일 비율로 높여주는 문제가 있다. 이와 같은 보청기로 보정하게 되면, 주파수 대역별 균형이 맞지 않기 때문에 소리가 변형되어 들리게 되고, 명료도 또한 떨어지게 된다. 또한, 기존의 아날로그보청기는 생산공정 중에 잡음 피크 제거, 리미터 조정, 이득 조정(GC) 등의 작업을 수동으로 수행하게 되는데, 이는 작업공정이 복잡하고 개개인에 청각특성에 맞는 정확한 보정이 불가능한 문제점을 안고있다. 이와 같은 문제점을 해결하기 위하여 제안한 자동보정 시스템은 각 주파수 대역별 최적화된 파라미터를 자동적으로 찾아서 입력하므로 보다 정확하고 신속한 보정이 가능하게 된다. 이 시스템은 외부 IC 콘트를 장치인 Hl-PRO를 이용하여 PC 환경 하에서Visual Basic으로 구현하였으며 시스템의 출력값을 측정하여 검토한 결과 구현한 자동보정법이 유효함을 확인할 수 있었다.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.213-218
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• 2008

동일 지점을 촬영한 위성영상은 위성의 센서나 영상의 취득 시기, 지형의 상태 등에 따라 그 지점에 나타나는 화소값이 일정하지 않다. 이러한 영상은 영상간 모자이크나 변화 탐지 결과에 영향을 미칠 가능성이 높으므로 방사보정(또는 방사정규화)을 통해 화소값의 차이를 최소화시킬 필요가 있다. 본 연구는 선형회귀식을 적용한 상대 방사정규화에 초점을 맞추고 있으며, 선형회귀식 구성에 필요한 PIF(Pseudo Invariant Feature)를 자동으로 추출하기 위해 Ordinal Rank 알고리즘을 적용하였다. 이 방법을 통해 각 밴드별 후보 PIF를 추출하고, 공통으로 해당되는 최종 PIF를 추출할 수 있었다. RMSE(Root Mean Square Error), Dynamic range, Coefficient of variation 등을 통해 방사보정 후의 결과를 평가해보았다. 영상회귀를 이용한 방사보정알고리즘과의 비교를 통해 제안된 알고리즘이 갖는 장점을 확인하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.644-647
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• 2010

본 논문에서는 영역분할을 이용한 3D입체영상의 밝기 보정방법을 제안한다. 제안된 방법은 입력된 좌우 3D입체영상 중 우 영상을 이진화를 통한 영역분할을 하고 크기가 작은 영역들은 제거한다. 영역단위의 매칭을 할 때 영역경계에서 발생하는 불연속성을 제거하기 위해서 모폴로지 필터로 영역경계지역(contour region)을 일정부분 제거한다. 우 영상의 각 영역들에 대해 대응되는 좌 영상내의 영역을 상관계수(correlation coefficient)를 이용한 정합을 통해 추출한다. 좌우 영상의 영역 간 히스토그램 명세화를 수행함으로써 우 영상의 밝기 보정을 한다. 실험에서 좌 영상으로부터 블록단위 움직임보상으로 우 영상을 생성했을 때 제안한 방법이 블록평균 정합오차가 가장 작은 것을 확인 할 수 있었다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.3
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• pp.323-330
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• 2009

The demand that we are monitoring security and crime of the urban facilities is increasing recently, but the using CCTV devices are expensive. In this research, we enlarge the angle of view using the Fish-eye Lens and the Photogrammetry, the efficiency of monitoring enhance. First, we carry out the calibration of the Fish-eye Lens indoors, we calculate the correction parameters, and then covert the original image-point to new image-point correcting distortion. Second, the correction program with the correction parameters can obtain the real-time correcting image. Lastly, for authorization the developed program we compare correcting-image with scanning-imge, it is showed the RMSE is 3.2pixel.

• The korean journal of orthodontics
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• v.26 no.3
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• pp.267-279
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• 1996

This study was investigated the changes during treatment and retention period in the Class III malocclusion patients and explored the correlationship between factors that showed relapse tendencies and pre-treatment skeletal pattern and the changes during treatment period. Numbers of total sample were 24 and their Hellman's dental age at the start of treatment was over III B and were retained at least over 1 year 6 months. The following conclusion were obtained by comparing the differences between treatment period and retention period, and after analysing the correlationship of factors that manifested relapse tendencies. 1. The angles formed by FH plane and occlusal plane, FH plane and mandibular plane, and mandibular incisor and mandibular plane changes showed rebound effect during retention period and among them occlusal plane angle and IMPA show reverse correlationship. 2. Upward displacement of the occlusal plane at the end of treatment has returning tendency, is proportional to the displacement during treatment period, but the angle between maxillary and mandibular 1st molar to its basal bone have been constantlsy maintained during the retention period. 3. Mandibular plane decrease during retention period and downward backward rotation during treatment period show correlationship.

• KSBB Journal
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• v.19 no.4
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• pp.269-273
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• 2004

A simple, fast and reproducible quantitative analysis method for sugar concentration composed in oligosaccharide mixture was developed. Two glass TLC plates were prepared per sample. After dipping one plate into the copper bicinchoninate reagent and the other plate into 5% sulfuric acid solution, both plates were baked in microwave oven until sugar spots were developed or the surface temperature of TLC plate becomes 60 to 70 $^{\circ}C$. The corrective factor values [F value =(the value of total sugar concentration converted as glucose unit/the value of reducing sugar concentration converted as glucose unit)/(polymerization degree of sugar)] of different molecular weight sugars were determined. Within the concentration of 0.25∼1.0 $\mu\textrm{g}$ in each sample loaded, the fructose-F (corrective factor value of fructose) was 0.45, yet for the higher concentration (2.5∼7.5 $\mu\textrm{g}$) fructose-F was 1.0. In case of glucose, in the range of 0.5∼7.5 $\mu\textrm{g}$, glucose-F was same as fructose-F, 1.0. However, as the molecular weight of sugar was increased, the F values were decreased in both maltodextrin and isomaltodextrin oligosaccharides in 0.5∼7.5 $\mu\textrm{g}$ of each sample loaded. Interestingly, F values were equal for the same molecular weight sugars, although the structures were different from each other. Using F value of each sugar, we could determine and compare the exact total sugar concentration of different molecular weight maltooligosaccharide and isomaltooligosaccharide. We also could determine if the unknown sugar was a reducing or non-reducing compound by using optimized TLC with microwave oven method.

• Survey Research
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• v.5 no.2
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• pp.31-48
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• 2004

We collected and analyzed 18 social surveys to assess the quality of samples with respect to region, gender, age-band, education level and occupation. We found in our samples that highly educated people and house wives are over-represented whereas low educated people, self-employed/blue collars and white collars are under-represented. To correct such sample distortions, we applied the iterative proportional weighting or the raking to our samples. We observed sizable changes in survey results. Also, the effective sample sizes were shrunken up to 20%-40%, that could be interpreted as the necessity of larger samples to meet the claimed sampling error limits.

• Journal of Broadcast Engineering
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• v.25 no.4
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• pp.598-608
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• 2020

In this paper, we propose a color correction technique for images acquired through a multi-view camera system for acquiring a 3D model. It is assumed that the 3D volume is captured indoors, and the position and intensity of the light is constant over time. 8 multi-view cameras are used, and converging toward the center of the space, so even if the lighting is constant, the intensity and angle of light entering each camera may be different. Therefore, a color optimization function is applied to a color correction chart taken from all cameras, and a color conversion matrix defining a relationship between the obtained 8 images is calculated. Using this, the images of all cameras are corrected based on the standard color correction chart. This paper proposed a color correction method to minimize the color difference between cameras when acquiring an image using 8 cameras of 3D objects, and experimentally proved that the color difference between images is reduced when it is restored to a 3D image.

• Journal of Environmental Impact Assessment
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• v.22 no.2
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• pp.157-170
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• 2013

수질오염총량관리제 시행 하천에 대해서는 객관적이고 과학적 방법으로 유역내 각 지역의 오염부하량을 할당할 필요가 있다. 본 연구에서는 대도시에서 배출되는 오염부하의 영향을 크게 받는 영산강수계의 중상류부를 대상으로 오염부하량 할당 방법에 대해 검토하였다. 오염부하량 할당을 위한 수질모델링은, 수질관리에 흔히 적용되어온 QUAL2E의 최근 판인, QUAL2Kw를 이용해서 수행하였다. 모델 적용 대상 지역의 각 reach의 수질매개변수는 QUAL2Kw의 자동보정 기능을 이용해서 추정하였다. 오염부하량 할당의 최적화는 유전알고리즘(genetic algorithm)을 이용하였고, 최소부하량 삭감법(least waste load removal allocation), 일정 부하량 이상 최소부하량 삭감법(least waste load removal over a certain value), 동일삭감률 할당법(equal removal rate)의 세가지 방법을 적용하고 비교 검토하였다. 동일삭감률 할당법은 다른 방법보다 유역 전체 부하량 삭감량이 훨씬 크기 때문에 효과적이지 않았고, 이 방법을 쓰기 위해서는 부하량 삭감대상인 각 소유역과 하수처리장을 그 규모와 특성에 따라 세분화할 필요가 있다. 동일삭감률 할당법의 적용시 세가지 범주로 나누어서 삭감률을 적용하였다. 오염부하량 삭감의 효율성을 감안할 때 최소 부하량 삭감법보다 일정 부하량 이상 최소부하량 삭감법이 더 적절한 것으로 검토되었다.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.315-322
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• 2010

The phase-screen and the split-step Fourier migrations, which are implemented in both the frequency-wavenumber and frequency-space domains by using one-way scalar wave equation, allow imaging in laterally heterogeneous media with less computing time and efficiency. The generalized-screen migration employs the series expansion of the exponential, unlike the phase-screen and the split-step Fourier migrations which assume the vertical propagation in frequency-wavenumber domain. In addition, since the generalized-screen migration generalizes the series expansion of the vertical slowness, it can utilize higher-order terms of that series expansion. As a result, the generalized-screen migration has higher accuracy in computing the propagation with wide angles than the phase-screen and split-step Fourier migrations for media with large and rapid lateral velocity variations. In this study, we developed a 2D prestack generalized-screen migration module for imaging a complex subsurface efficiently, which includes various dips and large lateral variations. We compared the generalized-screen propagator with the phase-screen propagator for a constant perturbation model and the SEG/EAGE salt dome model. The generalized-screen propagator was more accurate than the phase-screen propagator in computing the propagation with wide angles. Furthermore, the more the higher-order terms were added for the generalized-screen propagator, the more the accuracy was increased. Finally, we compared the results of the generalizedscreen migration with those of the phase-screen migration for a model which included various dips and large lateral velocity variations and the synthetic data of the SEG/EAGE salt dome model. In the generalized-screen migration section, reflectors were positioned more accurately than in the phase-screen migration section.