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Yongsu Yoon(윤용수) 대한방사선과학회(구 대한방사선기술학회) 2017 방사선기술과학 Vol.40 No.4
진단용 X선 영상에서 산란선은 화질을 열화시키는 주요한 원인이다. X선 장치는 필름/스크린을 사용한 아날로그 시스템부터 Imaging plate (IP) 및 평판 검출기(Flat panel detector; FPD)를 사용한 디지털 시스템으로 바뀌어가고 있다. 그러나 산란 X선 제거를 위한 Grid는 아날로그 시대에 사용됐던 구조부터 큰 변화가 없다. 본 논문에서는 선행연구에서 고안된 산란선 제거율을 향상시키기 위한 간접변환형 평판검출기의 새로 운 구조를 다양한 입사 X선을 사용하는 임상현장에서의 활용 가능성을 검토했다. 일반적으로 FPD는 3개의 층으로 구성되어 있다. 신호를 검출하는 화소와 화소 사이에는 전압을 거는 voltage line이나 데이터를 전달하는 data line과 같은 X선 불감영역이 존재한다. 선행연구에서는 이 불감영역에 정확히 맞추어 방사선 불 투과성의 납을 그물 모양으로 substrate layer에 삽입함으로서 검출기 자체가 산란선 제거 효과가 있도록 설계하였다. 새로운 구조의 임상 유용성을 평가하기 위해, 삽입된 그물 모양의 납을 입사 X선에 대해 가로, 세로성분으로 나누어 각각의 성능을 확인하였으며, 동시에 납의 높이를 변화시켜 납 높이가 성능에 미치는 영향을 영상 대조도와 grid 노출 인자를 통해 검토했다. 검출기면에 대해 대각선으로 입사한 X선(0°, 15°, 30°)에 대해서, 입사 X선에 대해 평행한 가로성분이 세로 성분에 비해 높은 영상 대조도와 낮은 그리드 노출 인자를 나타냈으며, 세로성분의 납 높이가 높을수록 본 연구에서 고안한 검출기에 악영향을 미치는 것을 확인했다. 그러므로 본 연구에서 고안한 새로운 FPD 시스템은 FPD의 구조를 방사선검사 조건과 목적에 맞추어 최적화함으로써 임상 의료현장에서의 사용 가능성이 확인되었다. In diagnostic radiology, the imaging system has been changed from film/screen to digital system. However, the method for removing scatter radiation such as anti-scatter grid has not kept pace with this change. Therefore, authors have devised the indirect flat panel detector (FPD) system with net-like lead in substrate lay-er which can remove the scattered radiation. In clinical context, there are many radiographic examinations with angulated incident X-ray. However, our proposed FPD has net-like lead foil so the vertical lead foil to the an-gulate incident X-ray would have bad effect on its performance. In this study, we identified the effect of verti-cal/horizontal lead foil component on the novel system s performance and improved the structure of novel sys-tem for clinical usage with angulated incident X-ray. Grid exposure factor and image contrast were calculated to investigate various structure of novel system using Monte Carlo simulation software when the incident X-ray was tilted (0°, 15°, and 30° from the detector plane). More photons were needed to obtain same image quality in the novel system with vertical lead foil only then the system with horizontal lead foil only. An optimal structure of novel system having different heights of its vertical and horizontal lead foil component showed im-proved performance compared with the novel system in a previous study. Therefore, the novel system will be useful in a clinical context with the angulated incident X-ray if the height and direction of lead foil in the sub-strate layer are optimized as the condition of conventional radiography.
Inhibition of Cell Proliferation and Migration by miR-509-3p That Targets CDK2, Rac1, and PIK3C2A
Yoon, Sena,Han, Eunji,Choi, Young-Chul,Kee, Honghwan,Jeong, Yongsu,Yoon, Jaeseung,Baek, Kwanghee Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.4
CDK2 is a key regulator of cell cycle progression. In this study, we screened for miRNAs targeting CDK2 using a luciferase-3'-untranslated region reporter assay. Among 11 hit miRNAs, miR-509-3p reduced CDK2 protein levels and significantly inhibited cancer cell growth. Microarray, Western blotting, and luciferase reporter analyses revealed additional targets of miR-509-3p, including Rac1 and PIK3C2A. Overexpression of miR-509-3p induced G1 cell-cycle arrest and inhibited colony formation and migration. RNAi experiments indicated that the growth-inhibitory effects of miR-509-3p may occur through down-regulation of CDK2, Rac1, and PIK3C2A. Targeting of multiple growth regulatory genes by miR-509-3p may contribute to effective anti-cancer therapy.
Induction of growth arrest by miR-542-3p that targets survivin
Yoon, Sena,Choi, Young-Chul,Lee, Suman,Jeong, Yongsu,Yoon, Jaeseung,Baek, Kwanghee Elsevier 2010 FEBS letters Vol.584 No.18
<P><B>Abstract</B></P><P>Survivin is a protein which functions as a mitotic regulator as well as apoptosis inhibitor. In this study, we show that introduction of synthetic miR-542-3p mimetic reduced both mRNA and protein levels of survivin. In A549 cells, luciferase reporter assay revealed that miR-542-3p targeted predicted binding sites in the 3′-untranslated region (3′-UTR) of survivin. We also demonstrate that ectopic expression of miR-542-3p inhibited cell proliferation by inducing Gap 1 (G1) and Gap 2/Mitosis (G2/M) cell cycle arrest. Collectively, these results suggest that survivin is a direct target of miR-542-3p and growth inhibition by miR-542-3p may have a potential utility as an anti-cancer therapy.</P>
3차원 패턴 레이저를 이용한 유영어류의 형태 및 크기 측정
양용수 ( Yongsu Yang ),이경훈 ( Kyounghoon Lee ),편용범 ( Yongbeom Pyeon ),윤은아 ( Eun A Yoon ),이동길 ( Dong Gil Lee ),조현수 ( Hyun Su Jo ) 한국어업기술학회 2016 수산해양기술연구 Vol.52 No.2
This study aims to estimate the species, size and shape of fish using a non-contact 3 dimensional pattern laser so that this preliminary test was carried out to understand the structural feature and length of goldfish according to water turbidity and depth in the aquacultural tank. 3-D pattern laser could clearly detect its morphological shape except the caudal fin due to soft tissue. Since the sensing strength of line laser light according to depth has sufficient power, it is possible to measure its depth and structural feature in the detected range. The result showed that the measured error of individual`s fork length was less than ±1% in the water using 3-D pattern laser, when compared with the measured value in the air.
Secure distribution of neural networks in wireless sensor networks
Joo Seung Yoon,Hee Moon Kim,Gil Ju Lee,Il Hee Kim,Yongsu Park 보안공학연구지원센터 2007 International Journal of Security and Its Applicat Vol.1 No.2
In this paper we consider the case where artificial neural network processing is securely performed over the wireless sensor network. To do this, we point out major security threats and countermeasures against them. Then, we revised Holenderski et al.’s decomposition model to support secure computing. Moreover, we refine the original model to deal with some boundary cases. The revised model shows that like the original model the horizontal decomposition is better than the vertical decomposition and that the number of the allocated lower neurons in each layer to each sensor node should be large for optimization.
태양광 발전시스템에서 PV의 부분 음영에 따른 부정합 손실 분석 및 개선방안 고찰
윤병근(ByungKeun Yoon),김승연(SeungYeon Kim),최상백(SangBack Choi),진용수(YongSu Jin),윤철(Chul Yun),권우현(WhooHyen Kwon) 한국신재생에너지학회 2016 신재생에너지 Vol.12 No.4
Generally PV power generation system consist of parallel connection of the PV strings which serially connected PV modules. Partial shading has effect on efficiency of PV power generation system, causing mismatch between PV strings. Compensation methods to reduce the mismatch loss have been investigated. these methods prefer to compensate the shaded PV modules increase system cost PV module weight. This paper suggests new method to reduce mismatch loss by compensating voltage to the string not to PV modules. Recognition of mismatch string is by comparing current between strings. only undervoltage is variably compensated to shaded string with low voltage source. imulation results with MATLAB/SIMULINK confirms the improvement of generation efficiency and compensation profit ratio.