한국인 담석증에 대한 임상적 고찰

김광하(Gwang Ha Kim),옥창민(Chang Min Ok),김병진(Byung Jin Kim),주형준(Hyung Jun Joo),송철수(Chul Soo Song),송근암(Guen Am Song),조몽(Mong Cho),양웅석(Ung Suk Yang) 대한소화기학회 1997 대한소화기학회지 Vol.29 No.3

N/A Background/Aitns: It has been reported frequently that clinical features of gallstone diseases in Koreans were different from those of Occidentals. These differences were thought to be due to inherent racial difference and acquired living habits. The purpose of this study is to evaluate whether the pattern of gallstone disease changes or not in Korea. Methods: We analyzed 5,488 cases of gallstone diseases which were reported in Korea frorn 1966 to 1994. We divided the period into 6 groups: the first period was 1,000 cases reported from 1966 to 1970, the second was 331 cases from 1971 to 1975, the third was 1,000 cases from 1976 to 1980, the fourth was 1,957 cases from 1981 to 1985, the fifth was 1,000 cases from 1986 to 1990, and the sixth was 200 cases from 1991 to 1993. Results: The age group of highest incidence was the fifth and sixth decade. The incidence below the third decade showed a decreasing tendency. In contrast, the incidence above sixth decade showed an increasing tendency. The male to female ratio was 1:1.25 to 1:1.71 and had no periological change. The duration of illness of highest frequency was below 6 months. In the case of duration above 5 years these was a decreasing tendency. The major complaints of biliary stone were right upper quadrant pain and tenderness. Nausea, vomiting, jaundice, and radiating pain showed a decreasing tendency. The major laboratory findings were leukocytosis, elevated SGOT and SGPT, elevated alkaline phosphatase, hyperbilirubinemia and hypoalbuminemia. Of these, only hypoalbuminernia had a decreasing tendency. By the second period, the main diagnostic procedures were oral cholecystogram and intravenous cholecysto- graphy. From the fourth period, ultrasonography, ERCP, CT and PTC were been used comrnonly. For the location of gallstone, the gallbladder stone revealed the only increasing tendency, the common bile duct stone had a decreasing tendency, and the intrahepatic duct stone had no periological change. From 1980, the cholesterol stone became the main composition of gallstones. But, there was no periological change between early and late 1980s. Positive bacterial culture rate was 57.0% and the most common microorganism was E. coli. Klebsiella and Enterobacter. Pseudomonas showed an increasing tendency. Of the diseases associated with gallstone, only diabetes had an increasing tendency. The frequency of residual stone had an increasing tendency. Conclusions: The age of peak incidence of gallstone diseases was the fifth and sixth decades and there was a little predominance in females. From 1980, the cholesterol stone becarne the main composition of gallstones. For the location of gallstone, the gallbladder stone showed an increasing tendency and the common bile duct stone revealed a decreasing tendency. These suggested clinical features of gallstone diseases in Koreans are somewhat similar to those of Occidentals. (Korean J Gastroenterol 1997;29:352 - 361)

광섬유 연결 반도체레이저 여기 세라믹 Nd:YAG 레이저에서 열렌즈 효과에 의한 출력특성

옥창민,김병태,김덕래,Ok, Chang-Min,Kim, Byung-Tai,Kim, Duck-Lae 한국광학회 2006 한국광학회지 Vol.17 No.5

광섬유 연결 반도체레이저를 여기원으로 하는 단면여기 세라믹 Nd:YAG 레이저의 출력 특성과 레이저 출력에 영향을 미치는 열 영향에 대하여 연구하였다. 반사율이 90.4 %인 출력거울을 사용하였을 경우 약 33.8 %의 최대 출력 효율을 얻었고, 기울기 효율은 39.3 %를 나타내었다. 세라믹 Nd:YAG의 열렌즈 효과에 의해 여기 파워 6 W 이상에서 출력 감소 현상이 나타났으며, 12 W 부근에서 레이저가 발진되지 않았다. The output characteristics of a ceramic Nd:YAC laser pumped by a fiber-coupled laser diode was investigated. An efficiency and a slope efficiency of 33.8 % and 39.3 % respectively were obtained, under an output coupler reflectance of 90.4 %. The laser power has decreased suddenly due to the thermal tensing effect more than 6 W pumping powers.

줌렌즈 광속확대기를 적용한 레이저 레이더용 송수광 내접형 광학계 설계

고해석,옥창민,홍진석,이창재,박찬근,김현규,Koh, Hae Seog,Ok, Chang Min,Hong, Jin Sug,Lee, Chang Jae,Park, Chan Geun,Kim, Hyun Kyu 한국광학회 2013 한국광학회지 Vol.24 No.1

In this paper, an optical system was designed for 3D imaging laser radar with optical scanner. In order to make it easy to scan, the system was designed to inscribe the transmitting objective lens in the receiving lens. In transmitting optics, the beam expander was designed to have a zoom mechanism so that the transmitted beam size would be 4.8 m or 6.8 m at 1 km distance, when the laser source's numerical aperture value is between 0.13 and 0.22. The beam diameter at the target 1 km away was confirmed by design program. The receiving optics for the returning beam from the target was designed for the $16{\times}16$ array detector with $100{\mu}m$ pixel width. The spot diameter in every pixel was designed and verified to be less than $55{\mu}m$. The receiving optics' obscuration ratio by transmitting optics was 11%. 송광광학계의 광원으로 사용되는 광섬유 레이저의 개구수, NA가 0.13~0.22의 범위에 있으면, 이 NA에 관계없이 1 km 전방에서 빔직경이 4.8 m 또는 6.8 m이 되도록 줌렌즈형 광속확대기를 적용한 송광광학계를 설계하였으며, 표적에서의 foot prints를 통하여 빔직경을 확인하였다. $16{\times}16$($100{\mu}m{\times}100{\mu}m$) 픽셀 검출기를 사용하는 수광광학계를 설계하였으며, 검출면의 픽셀 위치에 따른 spot diameter는 모두 $55{\mu}m$ 이하가 됨을 확인하였다. 스캔을 고려하여 송광광학계를 수광부 대물렌즈에 내접하도록 구성하였으며, 이때 송광부에 의하여 가려진 부분은 11%가 되었다.

광기구적 자동 비열화가 적용된 비정형 적외선 광각 카메라

김현숙,옥창민,Kim, Hyunsook,Ok, Chang Min 한국광학회 2015 한국광학회지 Vol.26 No.4

비정형(anamorphic) 렌즈가 적용된 적외선 광각 카메라 광학계를 제안하고 제작을 통해 그 유용성을 입증하였다. 개발된 적외선 카메라는 비정형 렌즈를 이용하여 수평방향에 대해서는 100도 이상의 넓은 시계를 제공하면서 수직방향에 대해서는 수평시계보다 큰 배율을 갖게 함으로써 증가된 해상도를 통해 장비의 광역 감시 및 탐지 능력을 동시에 향상시키는 특징을 갖는다. 또한 광기구적 자동 비열화 방법을 제안하고 시스템에 적용하여 그 성능 및 활용성을 확인하였다. A system of infrared camera optics with wide field of view and anamorphic lenses is proposed, and its validity verified through manufacture. The infrared camera produced provides a wide field of view of over 100 degrees in the horizontal direction, and an even greater magnification in the vertical direction. As a result, the system can have a wider surveillance range and improved detection ability at the same time. In addition, a new optomechanical automatic athermalization mechanism is proposed and applied to the infrared camera. Its performance and utility is proved through testing.

원거리 초분광 데이터 분류를 위한 환경 인자의 영향성 분석

김성호(Sungho Kim),옥창민(Chang Min Ok) 제어로봇시스템학회 2021 제어·로봇·시스템학회 논문지 Vol.27 No.8

This paper presents an analysis of the environmental effects on the remote hyperspectral image data classification. Spectral reflectivity and emissivity are unique properties for classifying materials in the short-wave and mid-wave infrared bands. However, various environmental factors such as solar radiation, atmospheric transmittance, and path radiance contaminate the object signature of reflectivity and emissivity, leading to degraded classification performance. Synthetic hyperspectral data sets are generated by using the radiative transfer equation and MODTRAN. The influence of each factor is analyzed quantitatively in terms of the material classification rate. These results can be fundamental guidelines in various hyperspectral signal processing in remote outdoor environments.

이중 시야 중적외선 광학계 비열화·나르시서스 분석

정도환,이준호,정호,옥창민,박현우,Jeong, Do Hwan,Lee, Jun Ho,Jeong, Ho,Ok, Chang Min,Park, Hyun-Woo 한국광학회 2018 한국광학회지 Vol.29 No.3

항공용 전자 광학 타겟팅 시스템을 위한 중적외선 광학계를 설계하였다. 본 광학계는 이중 시야를 갖도록 설계되었으며, 빔 축소 전단 광학계, 줌 렌즈 그룹, 릴레이 렌즈 그룹, 콜드스탑 공액 광학계 및 냉각 적외선 검출기로 구성된다. 적외선 검출기는 단일 화소의 크기가 $15{\times}15{\mu}m$ 인 $1280{\times}1024$ 화소 배열을 가지며 잡음을 최소화하기 위하여, f/5.3의 냉각 콜드스탑이 적용된 제품으로 선정하였다. 이중 시야 ($1.50^{\circ}{\times}1.20^{\circ}$, $5.40^{\circ}{\times}4.23^{\circ}$)는 두 개의 렌즈를 삽입하는 방식으로 구현했으며, 줌 배율 변경 시 모든 시야에 걸쳐 f/5.3의 콜드스탑의 효율을 유지하도록 설계하였다. 열 효과가 이미지에 미치는 영향을 조사하기 위해 비열화 및 나르시서스 분석을 수행하였으며, 비열화 분석은 $-55{\sim}50^{\circ}C$의 작동 온도를 기준으로 초점 이동과 잔여 고차 파면 수차에 조사하였고 제르니케 다항식을 이용한 민감도 분석을 수행하여 최적의 보상자를 선정하였다. 선정된 보상자의 최적 이동을 고려한 MTF 해상력을 확인한 결과, 작동 온도 전 구간에 걸쳐 요구조건인 33 lp/mm에서 축상 10% 이상의 성능을 유지하는 것을 확인하였으며, 나르시서스 분석 결과, NITD (Narcissus Induced Temperature Difference) 값이 $1.5^{\circ}C$ 이하가 되도록 설계 된 것을 확인하였다. We have designed a mid-infrared optical system for an airborne electro-optical targeting system. The mid-IR optical system is a dual-field-of-view (FOV) optics for an airborne electro-optical targeting system. The optics consists of a beam-reducer, a zoom lens group, a relay lens group, a cold stop conjugation optics, and an IR detector. The IR detector is an f/5.3 cooled detector with a resolution of $1280{\times}1024$ square pixels, with a pixel size of $15{\times}15{\mu}m$. The optics provides two stepwise FOVs ($1.50^{\circ}{\times}1.20^{\circ}$ and $5.40^{\circ}{\times}4.23^{\circ}$) by the insertion of two lenses into the zoom lens group. The IR optical system was designed in such a way that the working f-number (f/5.3) of the cold stop internally provided by the IR detector is maintained over the entire FOV when changing the zoom. We performed two analyses to investigate thermal effects on the image quality: athermalization analysis and Narcissus analysis. Athermalization analysis investigated the image focus shift and residual high-order wavefront aberrations as the working temperature changes from $-55^{\circ}C$ to $50^{\circ}C$. We first identified the best compensator for the thermal focus drift, using the Zernike polynomial decomposition method. With the selected compensator, the optics was shown to maintain the on-axis MTF at the Nyquist frequency of the detector over 10%, throughout the temperature range. Narcissus analysis investigated the existence of the thermal ghost images of the cold detector formed by the optics itself, which is quantified by the Narcissus Induced Temperature Difference (NITD). The reported design was shown to have an NITD of less than $1.5^{\circ}C$.

위 생검조직에서 PCR 을 사용한 Helicobacter pylori 검출

김광하(Gwang Ha Kim),옥창민(Chang Min Ok),유영일(Young Il Yu),허정(Jung Huh),최성호(Seong Ho Choi),송철수(Chul Soo Song),송근암(Geun Am Song),조몽(Mong Cho),양웅석(Ung Suk Yang),문한규(Han Kyu Moon) 대한내과학회 1997 대한내과학회지 Vol.52 No.5

N/A Objective: Helicobacter pylori (H. pylori) has been implicated in the pathogenesis of chronic gastritis, gastric ulcer, duodenal ulcer and gastric cancer. Histological examination and culture are considered to be the most specific tests, and rapid urease test and serological test are rapid but less specific tests. 'I he aim of this study was to investigate the efficiency of the polymerase chain reaction (PCR) assay as a procedure for the diagnosis of H, pylori infection in gastric biopsy specimens. Methods: Biopsy specimens were obtained from the gastric antrum within 2cm from the pyloric channel of 42 patients during endoscopy and submitted for the histological examination, CLO test, and PCR assay. At the same time, another biopsy specimens were obtained from the lesion for the diagnosis of the diseases. Also, blood was sampled for the measure of the value of IgM and IgG. Results: As the result of the histopathological examination, chronic gastritis was diagnosed in 13 patients, gastric ulcer in 11, duodenal ulcer in H, and gastric cancer in 10. By the histological examination of the antrum, H, pylori were found in 77% of chronic gastritis, 55% of gastric ulcer, 75% of duodenal ulcer, and 40% of gastric cancer. As a whole, the bacteria was identified in 62%, 60%, 88%, 90%, 69% of patients by histological test, CLD test, IgM, IgG, and P(;R respectively. The gold standard we used for the presence of bacteria was histological examination. Sensitivity, specificity, positive predictive value, ancl negative predictive value for PCR assay were 92%, 69%, 83% and 85% respectively. The results of other test were as follows. CLO test: 89%, 88%, 92%, 82%, IgM:92%, 19%, 65%, 60%, IgG:100%, 25%, 68%, 100%, Conclusion: CR is a very sensitive but some- what less specific test for the detection of H. pylori. This is mainly due to the contamination of H. pylori during endoscopy and biopsy. So, minimization of the contamination would make PCR clinically useful test.

1D-CNN을 이용한 초분광 이미지 분류에서 Dilated Convolution의 영향 분석

강병진(Byung-Jin Kang),조상호,옥창민(Chang-min Ok),김성호(Sung-Ho Kim) 대한전자공학회 2021 대한전자공학회 학술대회 Vol.2021 No.6

Recently, studies on hyperspectral image classification using deep learning are being conducted. Among these studies, the extraction of features of spectral information can be considered as the best match for the meaning of hyperspectral images. One Dimensional Convolution Neural Network is one of the most widely applied methods. In this paper, we investigate the effect of the Dilated Convolution Layer on the hyperspectral 1DCNN by applying the Dilated Convolution Layer instead of the pooling layer in 1D-CNN. Experiments were conducted using a public hyperspectral image dataset. The experimental results confirmed that Dilated Convolution has a good effect.

비열화 원적외선 광학계 설계 및 광학창 불균일 온도분포에 따른 영상 성능 연구

공현배(Hyun Bae Kong),강원석(Won Suk Kang),옥창민(Chang Min Ok),박현우(Hyun Woo Park),지호진(Ho Jin Ji) 한국항공우주학회 2019 한국항공우주학회 학술발표회 논문집 Vol.2019 No.11

난소에 전이를 일으킨 위암의 임상적, 병리학적 고찰

옥창민,이성훈,김형욱,이재승,강대환,송철수,송근암,조몽,양웅석 大韓消化器病學會 1998 大韓消化器病學會誌 Vol.32 No.6