http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Image Analysis for Specific Region Segmentation of Steel-tube Radiographic Images
JungWon Hwang,JaeHo Hwang 대한전자공학회 2007 ITC-CSCC :International Technical Conference on Ci Vol.2007 No.7
This paper describes an image analysis for region segmentation from gray-scale images of steel-tube radiographic detection without the usual step of binarization. A multi-stage approach is presented for boundary detected images, along with industrial application. Global contrast analysis is used in first stage to give a preliminary result, boundary and range. The second stage is a lineal segmentation in which both pixel location and intensity similarity are taken into account. Next stage then refines the threshold value based on local differentiation. By applying the modified fuzzy c-means algorithm, the spatial partitioning of a lineal pixels' set into sub-regions becomes context-oriented and fully iterative, unlike conventional spacial process. Analyzing results indicate that the steeltube radiographic images can be segmented into specific regions, even though noise, illumination and presence of shadows.
Hwang, Jungwon,Kim, Byoung Sik,Jang, Song Yee,Lim, Jong Gyu,You, Dong-Ju,Jung, Hyun Suk,Oh, Tae-Kwang,Lee, Jie-Oh,Choi, Sang Ho,Kim, Myung Hee National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.30
<P>Pathogenic and commensal bacteria that experience limited nutrient availability in their host have evolved sophisticated systems to catabolize the mucin sugar N-acetylneuraminic acid, thereby facilitating their survival and colonization. The correct function of the associated catabolic machinery is particularly crucial for the pathogenesis of enteropathogenic bacteria during infection, although the molecular mechanisms involved with the regulation of the catabolic machinery are unknown. This study reports the complex structure of NanR, a repressor of the N-acetylneuraminate (nan) genes responsible for N-acetylneuraminic acid catabolism, and its regulatory ligand, N-acetylmannosamine 6-phosphate (ManNAc-6P), in the human pathogenic bacterium Vibrio vulnificus. Structural studies combined with electron microscopic, biochemical, and in vivo analysis demonstrated that NanR forms a dimer in which the two monomers create an arched tunnel-like DNA-binding space, which contains positively charged residues that interact with the nan promoter. The interaction between the NanR dimer and DNA is alleviated by the ManNAc-6P-mediated relocation of residues in the ligand-binding domain of NanR, which subsequently relieves the repressive effect of NanR and induces the transcription of the nan genes. Survival studies in which mice were challenged with a ManNAc-6P-binding-defective mutant strain of V. vulnificus demonstrated that this relocation of NanR residues is critical for V. vulnificus pathogenesis. In summary, this study presents a model of the mechanism that regulates sialic acid catabolism via NanR in V. vulnificus.</P>
Jungwon Hwang,Myung Hee Kim 한국구조생물학회 2014 Biodesign Vol.2 No.2
Thioredoxin-interacting protein (TXNIP) regulates many biological processes by interacting with thioredoxin (TRX) in a redox-dependent fashion. Thus, elucidation of the mechanism, by which these two proteins interact, is a key to understand redox-dependent cell signaling. Recently, the TXNIP-TRX complex structure and their interacting mechanism have been published. Both TRX (containing 5 cysteine residues) and TXNIP (containing 11 cysteine residues) are highly redoxsensitive proteins, and are therefore extremely difficult to handle in vitro. Here, we present details of how these problematic redox proteins can be expressed, purified, and crystallized to a suitable quality for X-ray diffraction. Both proteins were expressed as a soluble complex in the E. coli Rosetta-gami (DE3) system in which disulfide bonds can form owing to trxB/gor mutation. Moreover, catching TXNIP in an intermediate state, in which TRX was bound, was crucial to obtain stable complex proteins linking to crystallization.
Hwang, Jungwon,Kim, Yoonjeong,Kang, Ho Bum,Jaroszewski, Lukasz,Deacon, Ashley M.,Lee, Hwiseop,Choi, Won-Chan,Kim, Kyung-Jin,Kim, Cheol-Hee,Kang, Beom Sik,Lee, Jie-Oh,Oh, Tae-Kwang,Kim, Jae Wha,Wilson, American Society for Biochemistry and Molecular Bi 2011 The Journal of biological chemistry Vol.286 No.14
<P>Considerable attention has recently been paid to the N-Myc downstream-regulated gene (<I>NDRG</I>) family because of its potential as a tumor suppressor in many human cancers. Primary amino acid sequence information suggests that the NDRG family proteins may belong to the α/β-hydrolase (ABH) superfamily; however, their functional role has not yet been determined. Here, we present the crystal structures of the human and mouse NDRG2 proteins determined at 2.0 and 1.7 Å resolution, respectively. Both NDRG2 proteins show remarkable structural similarity to the ABH superfamily, despite limited sequence similarity. Structural analysis suggests that NDRG2 is a nonenzymatic member of the ABH superfamily, because it lacks the catalytic signature residues and has an occluded substrate-binding site. Several conserved structural features suggest NDRG may be involved in molecular interactions. Mutagenesis data based on the structural analysis support a crucial role for helix α6 in the suppression of TCF/β-catenin signaling in the tumorigenesis of human colorectal cancer, via a molecular interaction.</P>
산업용 CR영상의 방사선 강도에 따른 잡음특성과 기하학적 구도형성의 해석적 접근
황중원(JungWon Hwang),황재호(JaeHo Hwang),박상기(SangKi Park) 대한전자공학회 2009 電子工學會論文誌-SP (Signal processing) Vol.46 No.1
산업용 강판튜브 CR영상의 잡음특성과 기하학적 구조에 관한 해석적 접근을 시도한다. 산업현장에서 방사선 측정실험으로 직접 취득한 방사선영상을 방사선강도에 따라 30(개) 이상의 샘플을 수집하였다. 이들 각 영상은 배경부, 두께부 및 튜브내부의 세 영역으로 구성되었는바, 그 가운데 튜브내부영역을 분석 대상으로 삼았다. 통계적이고 함수적인 방법론에 의해 잡음특성을 포함한 기하학적 구조를 분석한다. 영상을 구성하는 화소라인별로 또는 공간적으로 분석을 수행하여 강판튜브의 기하학적 원형 형태가 방사선영상화 과정을 거치면서 일어나는 변형과 잡음속성 변화의 두 가지 특성을 규명한다. 분석시 부합함수와 그 오차를 기하학적 변형의 판별인자로, 표준편차, 평균 및 SN비를 잡음특성 판별인자로 설정하고 방사선투과정도의 영상에서의 실현인 회색도 변화에 따른 이들 인자들의 변화를 고찰하였다. 분석결과, 본래의 원형 구조가 방사선투과 강도에 따라 타원형에서 저반경 원형 그리고 고반경원형의 점차적인 구조 변형을 일으킨다는 사실을 밝혔고, 잡음의 편차가 투과강도에 반비례함을 규명하였다. In this paper we investigate an analytical approach for noise properties and geometric structure in Computed Radiography(CR) images of industrial steel-tubes. Over thirty diverse radiographic images are sampled from industrial radiography measurements according to radiation intensity. Each image consists of three regions; background, thickness and inner-tube. Among these the region of inner-tube is selected for the object of analysis. Geometric structure which includes the noise generation is analyzed by the statistical and functional methodology. The analysis is carried on spacially and line by line. It verifies the geometrical transfigure from the circle configuration of steel-tube and noise variation. The estimation of fitting function and its error are the geometric factors. The statistics such as standard deviation, mean and signal-to-noise ratio are noise parameters for discrimination. These factors are considered under the intensity variation which is the penetrative strength of radiation. The analysing results show that the original geometry of circle is preserved in the form of elliptic or short/long diameter circle, and the noise deviation has increased inverse proportional to the radiation intensity.
황중원(JungWon Hwang),황재호(JaeHo Hwang) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
This paper proposes an regional analytic approach in image data space for radiographic image. Image is segmented into four regions, such as background, thickness, weld area and tube area, due to directional properties. Each region has its own gray level distribution, contrast range and noise property, originated from X-ray project mechanism and electric control system itself. Projection incorrectness and noise influence included on imaging quality is analyzed functionally and statistically. The experimental results shows not only segmental effects, but also visual edge evaluation.
황중원(JungWon Hwang),황재호(JaeHo Hwang) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
In this paper, we have verified the applicability of the line-clustering segmentation method to steel-tube X-ray images. Image data is partitioned into three regions on the base of vertical line edge detection. Parameters for necessary condition, such as neighborlity, similarity and directional neighbor correlation coefficients, proposed in that method is calculated and applied to such selected regions separately. Segmental features at each region is extracted statistically and functional classification is clustered by the point or space process. The analyzed data and experimental results show that the line-clustering segmentation method has a high applicability to X-ray image.
황중원(JungWon Hwang),황재호(JaeHo Hwang) 대한전자공학회 2007 대한전자공학회 학술대회 Vol.2007 No.7
We propose a contrast-controlled feature detection approach for steel radiograph image, X-ray images are low contrast, dark and high noise image. So, It is not simple to detect defects directly in automated radiography inspection system. Contrast enhancement, histogram equalization and median filter are the most frequently used techniques to enhance the X-ray images. In this paper, the adaptive control method based on contrast limited histogram equalization is compared with several histogram techniques. Through comparative analysis, CLAHE(contrast controlled adaptive histogram equalization) can enhance detection of defects better.