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권정현,장홍래,성제중,안형근,장순재,송문호 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1
The nondestructive testing using ultrasonic pulse-echo data is an effective test methodology esperially for metal structure. Typically, the ultrasonic pulse-echo data is processed and the results are shown in A-scan, B-scan or C-scan formats. Upon viewing B-scan and C-scan data the viewer is able to identify the location of faults as well as their rough dimension. In this paper, we evaluate the applicability of various 3-D visualization methods frequently used in medical imaging, namely, surface rendering (SR), volume rendering (VR) and maximum intensity projection (MIP), for nondestructive testing purposes. Such 3-D visualization of ultrasonic pulse-echo data enables easier identification of the location and dimension of faults more accurately.
Cho, Eun Sook,Jin, Byung Rae,Sohn, Hung Dae,Choi, Kwang Ho,Kim, Soung Ryul,Kang, Seok Woo,Yun, Eun Young,Kim, Sang Hyun,Kim, Keun Young,Je, Yeon Ho,Kang, Seok Kwon 한국잠사학회 1998 한국잠사곤충학회지 Vol.40 No.2
To construct transfurmed Bm5 cells, Autographa californica nuclear polyhedrosis virus(AcNPV) IE1 gene, an immediate early viral gene was firstly used in this study. AcNPV IE1 gene, which shares on 95.3% nucleotide sequence homology with Bombyx mori nuclear polyhedrosis virus (BmNPV) IE1 gene, was isolated and cloned into pBluescript. Neomycin gene from pKO-neo was inserted under the control of the IE1 promoter to yield pAcIE1-neo. The plasmid pAcIE1-neo was transfected into Bm5 or Sf9 cells, and neomycin-resistant cells were selected in TC100 medium containing 10% fetal bovine serum (FBS) and 1 mg/ml G4l8 for two weeks. Individual clones were picked and each was amplified for further characterization. The genomic DNA from neomycin-resistant cells was isolated and characterized by PCR using AcNPV IEI gene-specific primers and by Southern blot analysis using neomycin gene probe. We concluded that AcNPV IE1 gene was functional in B. mori-derived Bm5 cells as well as Spodoptera fugjprrda-derived Sf9 cells to produce stably-transformed insect cells
Electrical conductivity imaging using a variational method in <i>B<sub>z</sub></i>-based MREIT
Kwon, Ohin,Park, Chunjae,Park, Eun-Jae,Seo, Jin Keun,Woo, Eung Je Institute of Physics 2005 Inverse problems Vol.21 No.3
<P>Magnetic resonance electrical impedance tomography (MREIT) is a new conductivity imaging modality that was motivated to deal with the well-known ill-posedness problem in electrical impedance tomography (EIT). In order to bypass this ill-posed nature, MREIT takes advantage of an MRI scanner as a tool to capture the <I>z</I>-component <I>B<SUB>z</SUB></I> of the induced internal magnetic flux density <B>B</B> = (<I>B<SUB>x</SUB></I>, <I>B<SUB>y</SUB></I>, <I>B<SUB>z</SUB></I>) due to an injection current. Here, <I>z</I> is the direction of the main magnetic field of the MRI scanner. In this work, we propose an enhanced version of the variational gradient <I>B<SUB>z</SUB></I> algorithm that benefits from a careful use of boundary conditions in a variational formulation of the <I>B<SUB>z</SUB></I>-based MREIT model. We found that the proposed algorithm is advantageous especially in dealing with conductivity images near the boundary of the subject. Improvements in reconstructed image quality are shown by numerical simulations.</P>
MAGNETIC RESONANCE ELECTRICAL IMPEDANCE TOMOGRAPHY
Kwon, Oh-In,Seo, Jin-Keun,Woo, Eung-Je,Yoon, Jeong-Rock Korean Mathematical Society 2001 대한수학회논문집 Vol.16 No.3
Magnetic Resonance Electrical Impedance Tomography(MREIT) is a new medical imaging technique for the cross-sectional conductivity distribution of a human body using both EIT(Electrical Impedance Tomography) and MRI(Magnetic Resonance Imaging) system. MREIT system was designed to enhance EIT imaging system which has inherent low sensitivity of boundary measurements to any changes of internal tissue conductivity values. MREIT utilizes a recent CDI (Current Density Imaging) technique of measuring the internal current density by means of MRI technique. In this paper, a mathematical modeling for MREIT and image reconstruction method called the alternating J-substitution algorithm are presented. Computer simulations show that the alternating J-substitution algorithm provides accurate high-resolution conductivity images.
Kwon, Hyeuknam,McEwan, Alistair L.,Oh, Tong In,Farooq, Adnan,Woo, Eung Je,Seo, Jin Keun Hindawi Publishing Corporation 2013 Computational and mathematical methods in medicine Vol.2013 No.-
<P>Electrical Impedance Tomography (EIT) is a very attractive functional imaging method despite the low sensitivity and resolution. The use of internal electrodes with the conventional reconstruction algorithms was not enough to enhance image resolution and accuracy in the region of interest (ROI). We propose a local ROI imaging method with internal electrodes developed from careful analysis of the sensitivity matrix that is designed to reduce the sensitivity of the voxels outside the local region and optimize the sensitivity of the voxel inside the local region. We perform numerical simulations and physical measurements to demonstrate the localized EIT imaging method. In preliminary results with multiple objects we show the benefits of using an internal electrode and the improved resolution due to the local ROI image reconstruction method. The sensitivity is further increased by allowing the surface electrodes to be unevenly spaced with a higher density of surface electrodes near the ROI. Also, we analyse how much the image quality is improved using several performance parameters for comparison. While these have not yet been studied in depth, it convincingly shows an improvement in local sensitivity in images obtained with an internal electrode in comparison to a standard reconstruction method.</P>
시트도막복합방수공법에서의 비노출형 아스팔트 시트층의 용해원인 분석과 내용제성 필름을 이용한 누유방지 개선에 관한 연구
권기주(Kwon Ki-Joo),김동범(Kim Dong-Bum),송제영(Song Je-Young),곽규성(Kwak Kyu-Sung),오상근(Oh Sang-Keun) 대한건축학회 2010 大韓建築學會論文集 : 構造系 Vol.26 No.8
The purpose of this study is to provent asphalt dissolution by polyurethane coating contained volatile organic solvents in hybrid waterproofing system. if the asphalt that compose the waterproofing membrane is dissolved, it is lost its function of waterproof by decreasing thickness of waterproofing membrane. Furthermore, secondary damage caused by the asphalt meltage that flowed out from the Crack of Structures. The result of precedent study that analyze on the volatile organic solvents on the asphalt showed that the asphalt was dissolved when adding over 10% of volatile organic solvents and oil leakage was observed when adding 15% of volatile organic solvents. For this reason, in this study, nylon 6 films treated with corona is used to prevent the asphalt dissolution. The test was carried out on the same condition. The following is the experimental methods. First of all, after the nylon 6 films is laminated on surface of asphalt sheet, polyurethane coating spread with top of that. Then mortar spread with top of polyurethane coating again. Polyurethane coating used in this study is mixed with amount of volatile organic solvents of four types. the result of the test showed that every type wasn't dissolved and oil leakage wasn't observed.
Error Analysis of Nonconstant Admittivity for MR-Based Electric Property Imaging
Jin Keun Seo,Min-Oh Kim,Joonsung Lee,Narae Choi,Eung Je Woo,Hyung Joong Kim,Oh In Kwon,Dong-Hyun Kim IEEE 2012 IEEE transactions on medical imaging Vol.31 No.2
<P>Magnetic resonance electrical property tomography (MREPT) is a new imaging modality to visualize a distribution of admittivity γ = σ+<I>i</I>ωε inside the human body where σ and ε denote electrical conductivity and permittivity, respectively. Using B1 maps acquired by an magnetic resonance imaging scanner, it produces cross-sectional images of σ and ε at the Larmor frequency. Since current MREPT methods rely on an assumption of a locally homogeneous admittivity, there occurs a reconstruction error where this assumption fails. Rigorously analyzing the reconstruction error in MREPT, we showed that the error is fundamental and may cause technical difficulties in interpreting MREPT images of a general inhomogeneous object. We performed numerical simulations and phantom experiments to quantitatively support the error analysis. We compared the MREPT image reconstruction problem with that of magnetic resonance electrical impedance tomography (MREIT) to highlight distinct features of both methods to probe the same object in terms of its high- and low-frequency conductivity distributions, respectively. MREPT images showed large errors along boundaries where admittivity values changed whereas MREIT images showed no such boundary effects. Noting that MREIT makes use of the term neglected in MREPT, a novel MREPT admittivity image reconstruction method is proposed to deal with the boundary effects, which requires further investigation on the complex directional derivative in the real Euclidian space \BBR<SUP>3</SUP>.</P>