회전형 탐촉자의 다중균열 분해능이 증기발생기 전열관의 구조건전성 평가에 미치는 영향

강용석,천근영,남민우,박재학,Kang, Yong-Seok,Cheon, Keun-Young,Nam, Min-Woo,Park, Jai-Hak 한국비파괴검사학회 2014 한국비파괴검사학회지 Vol.29 No.1

회전형 탐촉자(RPC)는 증기발생기 전열관의 결함 탐지 및 크기 측정 목적으로 널리 사용되고 있다. 손상이 탐지된 전열관에 대한 건전성 평가는 비파괴검사에서 얻어진 열화의 크기 정보를 바탕으로 수행되기 때문에 검사기술의 성능은 전열관의 건전성 평가에 직접적으로 영향을 미치게 된다. 동일 전열관의 인접한 거리에 다중균열이 존재할 경우 검사 기술의 결함 분해능에 제약이 따를 수 있으며 그 영향이 클 경우 근접한 다중균열이 상대적으로 큰 단일균열로 평가될 수 있으므로 전열관의 구조건전성 평가에 오류를 유발할 수 있게 된다. 따라서 본 연구에서는 방전가공으로 균열을 모사한 인공결함에 대한 RPC 탐촉자의 결함 분해능을 관찰하고 전열관의 구조건전성 평가에 미치는 영향을 살펴보았다. 동일 직선상에 놓인 다중균열은 매우 근접한 거리까지 개별균열 식별이 가능하여 건전성 평가에 미치는 영향이 없는 반면, 인접한 거리에 평행하게 놓인 균열의 경우는 RPC 탐촉자의 분해능이 낮아서 부정확한 결함 크기 정보가 얻어지므로 결함관의 파열압력 예측에 영향을 미칠 수 있다. The eddy current testing performance directly affects the results of a steam generator tube integrity assessment because the integrity assessment of defected tubes is conducted based on eddy current testing results. This means that it may not be possible to accurately discriminate between adjacent flaws. This paper presents an investigation on the resolution of rotating pancake coils with multiple cracks and the effects on the structural integrity assessment of steam generator tubes.

혈액투석이 안압, 망막신경섬유층 두께 및 각막두께에 미치는 영향

강용석,황영훈,김재석,이주화,Yong Seok Kang,Young Hoon Hwang,Jae Suk Kim,Joo Hwa Lee 대한안과학회 2012 대한안과학회지 Vol.53 No.11

Purpose: To compare the intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness and central corneal thickness (CCT) in healthy individuals and patients with chronic renal failure (CRF) undergoing hemodialysis, and to evaluate the changes in each parameter before and after hemodialysis in patients with CRF. Methods: Thirty-six eyes of 36 patients with CRF undergoing hemodialysis were included in the hemodialysis group and 54 eyes of 54 healthy subjects were recruited as the control group. All subjects underwent a complete eye examination, including best-corrected visual acuity (BCVA), slit lamp examination, dilated funduscopic examination, gonioscopy, automated perimetry, IOP measurement, corneal pachymetry, and evaluation of RNFL thickness. In the hemodialysis group, IOP, RNFL thickness, and CCT were measured again within 1 hour of hemodialysis. Results: Age, sex, BCVA, cup-to-disc ratio, IOP, and CCT were not statistically different between the 2 groups. The RNFL of the hemodialysis group was statistically significantly thinner than the control group (p < 0.001). The IOP decreased from 16.52 ± 2.95 mm Hg to 14.88 ± 2.03 mm Hg after hemodialysis (1.63 ± 3.27 mm Hg; p = 0.005). The changes in RNFL thickness and CCT were not statistically significant (p = 0.148, p = 0.352). Conclusions: In CRF patients with hemodialysis, RNFLs were thinner in the control group and hemodialysis induced significant IOP reduction. The results from the present study should be considered for the proper evaluation of ocular disorders in CRF patients with hemodialysis.

원전 증기발생기 전열관 관막음 한계 고찰

강용석,이국희,Kang, Yong Seok,Lee, Kuk Hee 한국압력기기공학회 2020 한국압력기기공학회 논문집 Vol.16 No.2

Securing the integrity of steam generator tubes is an essential requirement for safe operation of nuclear power plants. Therefore, tubes that do not satisfy integrity requirements are no longer usable and must be repaired according to the related requirements. In general, the repair criterion is that the damage depth is more than 40% of the tube wall thickness. However, the plugging limit can be changed and be applied, provided a technical proof is given that integrity can be secured against specific degradation at a specific plants and that approval can be obtained from a regulatory agency. A typical example is alternative repair criteria for defects within the tube sheet or tube support plates. In this paper, a background of establishing the plugging limit for steam generator tubes and changes in maintenance criteria are reviewed as examples.

Detecting cell cycle-regulated genes using Self-Organizing Maps with statistical Phase Synchronization (SOMPS) algorithm

강용석(Kang, Yong-Seok),배철수(Bae, Cheol-Soo) 한국산학기술학회 2012 한국산학기술학회논문지 Vol.13 No.9

세포주기조절유전자를 식별하는 계산방법을 개발하는 것은 시스템 생물학의 중요한 주제중 하나이다. 이전 방법의 대부분은 세포주기 조절 유전자를 식별하는 표현신호의 주기적인 특성으로 간주한다. 그러나, 세포주기 조절 유전자는 상대적으로 세포 네트워크를 기반으로 서로 활성화된 상대적으로 많은 상호 작용을 일으킨다고 가정한다. 본 연구에서는 세포주기 분석에 변수 위상동기화 이론을 적용하여, "통계적상 동기화를 이용한 자가조직지도 (SOMPS)", 즉, 자가조직지도와 다변수 통계 동기화 방법으로 이루어진 방법을 사용하여 여러 개의 하위집합과의 상호작용을 발 생시키고자 한다. 평가방법으로 SOMPS방법 알고리즘이 세포주기조절 유전자를 방법으로 기존에 사용되는 방법들과 같이 유용할 것으로 보인다. Developing computational methods for identifying cell cycle-regulated genes has been one of important topics in systems biology. Most of previous methods consider the periodic characteristics of expression signals to identify the cell cycle-regulated genes. However, we assume that cell cycle-regulated genes are relatively active having relatively many interactions with each other based on the underlying cellular network. Thus, we are motivated to apply the theory of multivariate phase synchronization to the cell cycle expression analysis. In this study, we apply the method known as "Self-Organizing Maps with statistical Phase Synchronization (SOMPS)", which is the combination of self-organizing map and multivariate phase synchronization, producing several subsets of genes that are expected to have interactions with each other in their subset (Kim, 2008). Our evaluation experiments show that the SOMPS algorithm is able to detect cell cycle-regulated genes as much as one of recently reported method that performs better than most existing methods.

부산항 컨테이너 터미널 포지셔닝 분석에 관한 연구

강용석 ( Kang Yong-seok ),김유나 ( Kim Yu-na ),최영서 ( Choi Young-seo ),여기태 ( Yeo Gi-tae ) 한국해운물류학회 2022 해운물류연구 Vol.38 No.4

본 연구는 허핀달-허쉬만 지수(HHI) 및 BCG Matrix를 통해 부산항 컨테이너 터미널의 전략적 위치를 파악하는 것을 연구의 목적으로 한다. 연구결과는 다음과 같다. 첫째, 부산항 9개 컨테이너 전용 터미널의 운영 경쟁력을 2012년부터 2020년까지 연도별로 허핀달-허쉬만 지수를 통해 분석했다. 분석결과, 9개 전용 터미널이 부산항 내 선석을 나눠 가지면서 독과점 현상 없이 치우치지 않고 치열하게 경쟁을 하는 것으로 나타났다. 둘째, BCG Matrix 분석결과, 수입이 높고 안정적이며 성장세에 있는 Star 범위에 있는 터미널은 도출되지 않았다. Question Marks 범주에 5개 터미널, Dogs 범주에 3개 터미널 및 Cash Cow 범주에 1개 터미널이 위치했다. 셋째, BCG Matrix 동적 분석결과, 전반적인 부산항의 물동량은 지속 증가하는 것으로 나타났으나, 터미널별 처리물량은 서비스의 안정성, 효율성 등과 같은 다양한 요인과 기항하는 선대의 변화에 따라 수시로 증감이 이루어지고 있는 것으로 나타났다. In spite of various studies related to Busan Port, positioning analysis studies targeting individual container terminals of the North Port and New Port of Busan Port based on changes in the freight volume of Busan Port are quite limited. Given that the competitiveness of each terminal in Busan Port can be the basis for securing the overall competitiveness of Busan Port, the purpose of this study is to understand the positions of individual terminals in Busan Port in the market through the Herfindahl-Hirschman index (HHI) and BCG Matrix. The study results are as follows. First, the operational competitiveness of nine dedicated container terminals in Busan Port was analyzed by year from 2012 to 2020 through the HHI. According to the results of the analysis, tthe nine dedicated terminals share berths in Busan Port, are not biased without monopoly, and compete fiercely. Second, the BCG Matrix was analyzed and as a result, no terminals located in the Star range, which are interpreted as having high income and being stable and in a growth trend, were not derived. Five terminals were located in the Question Marks category, three terminals in the Dogs category, and one terminal in the Cash Cow category. Third, as a result of the dynamic analysis of the BCG Matrix, the overall cargo volume of Busan Port was shown to continuously to increase, but the handling volumes by terminal were shown to fluctuate frequently according to changes in the calling fleets according to various factors such as service stability and efficiency.

〈학술논문〉 한국표준형원전 증기발생기의 중앙공동부 주변 마모 특성 분석

강용석(Yong-Seok Kang),엄기수(Ki-Soo Um),박재학(Jai-Hak Park) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

It is well known that the major tube degradation mechanism observed in OPR1000 steam generator is tube support fretting wear. The root cause of tube fretting wear has been determined to be high fluid velocity in the central cavity in conjunction with relatively low natural frequency of the tubes adjacent to the central cavity. The designer of OPR1000 steam generator expected that fewer than 177 tubes will eventually have to be plugged as a result of this issues. In this study, we have investigated fretting wear characteristics at central cavity area of OPR1000 steam generators.

회전형 탐촉자의 다중균열 분해능이 증기발생기 전열관의 구조건전성 평가에 미치는 영향

강용석(Yong-Seok Kang),천근영(Keun-Young Cheon),남민우(Min-Woo Nam),박재학(Jai-Hak Park) 한국비파괴검사학회 2014 한국비파괴검사학회지 Vol.34 No.5

회전형 탐촉자(RPC)는 증기발생기 전열관의 결함 탐지 및 크기 측정 목적으로 널리 사용되고 있다. 손상이 탐지된 전열관에 대한 건전성 평가는 비파괴검사에서 얻어진 열화의 크기 정보를 바탕으로 수행되기 때문에 검사기술의 성능은 전열관의 건전성 평가에 직접적으로 영향을 미치게 된다. 동일 전열관의 인접한 거리에 다중균열이 존재할 경우 검사 기술의 결함 분해능에 제약이 따를 수 있으며 그 영향이 클 경우 근접한 다중균열이 상대적으로 큰 단일균열로 평가될 수 있으므로 전열관의 구조건전성 평가에 오류를 유발할 수 있게 된다. 따라서 본 연구에서는 방전가공으로 균열을 모사한 인공결함에 대한 RPC 탐촉자의 결함 분해능을 관찰하고 전열관의 구조건전성 평가에 미치는 영향을 살펴보았다. 동일 직선상에 놓인 다중균열은 매우 근접한 거리까지 개별균열 식별이 가능하여 건전성 평가에 미치는 영향이 없는 반면, 인접한 거리에 평행하게 놓인 균열의 경우는 RPC 탐촉자의 분해능이 낮아서 부정확한 결함 크기 정보가 얻어지므로 결함관의 파열압력 예측에 영향을 미칠 수 있다. The eddy current testing performance directly affects the results of a steam generator tube integrity assessment because the integrity assessment of defected tubes is conducted based on eddy current testing results. This means that it may not be possible to accurately discriminate between adjacent flaws. This paper presents an investigation on the resolution of rotating pancake coils with multiple cracks and the effects on the structural integrity assessment of steam generator tubes.

증기발생기 전열관지지판의 축균열 파열억제 효과 분석

강용석 ( Yong Seok Kang ),이국희 ( Kuk Hee Lee ),김홍덕 ( Hong Deok Kim ),박재학 ( Jai Hak Park ) 한국안전학회(구 한국산업안전학회) 2015 한국안전학회지 Vol.30 No.4

A steam generator tubing is one of the main pressure boundary of the reactor coolant system in the nuclear power plants. Structural integrity refers to maintaining adequate margins against failure of the tubing. Burst pressure of a tube at tube support plate can be higher than that for a free-span tube because failure behaviors could be interfered from the tube support plate. Alternative repair criteria for out-diameter stress corrosion cracking indications in tubes to the drilled type tube support plate were developed, however, there are very limited information to the eggcrate type tube support plate. This paper discussed reinforcement effect of steam generator tube burst pressure with axial out-diameter stress corrosion cracking within an eggcrate type tube support plate. A series of tube burst tests were performed under the room temperature and it was found out that there is no significant but marginal effects.

급성 HIV증후군으로 오인한 진행된 AIDS 1예

강용석 ( Yong Seok Kang ),하성삼 ( Seong Sam Ha ),성재호 ( Jae Ho Seong ),한용재 ( Yong Jae Han ),임유리 ( Yoo Li Lim ),이태식 ( Tae Sic Lee ),김효열 ( Hyo Yeol Kim ),김영근 ( Young Keun Kim ),김종구 ( Jong Koo Kim ),박연철 ( Yon 전북대학교 의과학연구소 2014 全北醫大論文集 Vol.38 No.2

Indeterminate western blot in HIV infection can be due to seroconversion during acute HIV infection, advanced HIV infection or infection with HIV-2. In this report, we describe a patient whose advanced HIV infection was identified by a positive combined antigen/ antibody test and detectable viremia, with an inch of being misdiagnosed as acute HIV syndrome. A 23-year-old male was admitted with fever, myalgia, diarrhea and weight loss. He denied previous history of HIV infection, sexual contact and transfusion. Indeterminate western blot result made us misdiagnosis as a seroconversion in acute HIV syndrome. He denied his disease and insisted to delay antiretroviral therapy until positive western blot results. We had question about very low CD4 cell count (22/uL), and asked HIV/AIDS national registry for his previous registration. He was diagnosed HIV infection via blood donor screening 22 months before admission, but was not informed of the result. Finally the patient was confirmed advanced HIV infection and started antiretroviral therapy.

새로운 논리값을 사용한 주사 환경을 위한 경로 지연 검사 입력 생성기에 관한 연구

강용석(Kang Yong Seok),강성호(Kang Sungho) 대한전자공학회 1996 대한전자공학회 학술대회 Vol.1996 No.11