• Journal of KIISE:Software and Applications
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• v.33 no.11
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• pp.942-952
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• 2006

We propose an automatic segmentation method for identifying pulmonary structures using gray-level information of chest CT images. Our method consists of following five steps. First, to segment pulmonary structures based on the difference of gray-level value, we select the threshold using optimal thresholding. Second, we separate the thorax from the background air and then the lungs and airways from the thorax by applying the inverse operation of 2D region growing in chest CT images. To eliminate non-pulmonary structures which has similar intensities with the lungs, we use 3D connected component labeling. Third, we segment the trachea and left and right mainstem bronchi using 3D branch-based region growing in chest CT images. Fourth, we can obtain accurate lung boundaries by subtracting the result of third step from the result of second step. Finally, we select the threshold in accordance with histogram analysis and then segment radio-dense pulmonary vessels by applying gray-level thresholding to the result of the second step. To evaluate the accuracy of proposed method, we make a visual inspection of segmentation result of lungs, airways and pulmonary vessels. We compare the result of the conventional region growing with the result of proposed 3D branch-based region growing. Experimental results show that our proposed method extracts lung boundaries, airways, and pulmonary vessels automatically and accurately.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.215-216
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• 2018

민간에 의한 경찰활동의 역사는 뿌리가 깊다. 자신과 가족의 보호로부터 시작된 경찰활동은 시간이 지남에 따라 그 영역을 넓히면서 더욱 구체화 되었다. 경찰활동은 공공에 의한 경우와 개인적 차원의 활동으로 구분할 수 있다. 경찰활동을 police activity, police operation, policing이라고 하는데 공공 또는 정부 차원에서 이루어지는 경찰활동은 public police activity, 개인적 차원 혹은 민간 차원의 경찰활동을 private police activity라고도 한다. 인류 역사 이래 스스로를 지키기 위한 경찰활동이 있었으며 국가체제에서도 경찰국가로 불리던 시기가 있었다. 시간이 지남에 따라 경찰활동 영역에도 많은 변화가 있었는데 공경찰활동은 국가 또는 중앙정부, 혹은 지방정부의 변화와 맥락을 같이한다. 민간경찰활동 역시 경찰활동을 요구하는 개인 또는 기업 등의 변화에 따라 많은 변화가 있었다. 민간에 의한 경찰활동은 정부의 공경찰활동이 미치지 못하는 영역에서 요구되었으며 이는 자연스럽게 민간경찰활동의 성장으로 귀결되었다. 단순하게 개인과 재산, 시설 등을 경비하던 수준에서 벗어나 이제는 연관되지 않은 영역이 없을 정도의 발전을 하였으며 과학적이고 기술적으로 진보되고 발전되었다. 앞으로는 첨단 시설과 장비는 물론이고 각종 데이터베이스를 기반으로 하는 인공지능의 활용이 더욱 활발할 것으로 기대된다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.2 no.2
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• pp.77-82
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• 1992

When a crystal is grown by FZ process, the melt zone is located at between the solid of upper and lower side and is kept by the solid-liquid interface tension. On the surface of the melt zone, a surface tension gradient is occured by the difference of temperature and solute concentration, it is the driving force of marangoni flow. The crystal even in the steady state growth can become imperfect for the dislocation distribution and the solute concentration in the peripheral region of the crystal are higher than those in the inner part and the probability of the formation of the defects such as voids, bubble penetration, secondary phase creation and crack is high near the solid-liquid interface. This is because the solid -liquid interface becomes irregular because of the local variation of temperature in that region due to marangoni convection.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.4
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• pp.180-183
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• 2001

$YVO_{4}$ and Nd:$YVO_{4}$ single crystals have been grown developed Edge-defined film-fed growth (EFG) method and the crystals were measured on optical properties. $YVO_{4}$ and Nd:$YVO_{4}$ single crystal were transparent, high quality due to homogeneity of surface temperature of the melt and stability of meniscus during crystal growth. In transmittance and absorption spectra, Nd:$YVO_{4}$ single crystals had absorption peaks at wavelengths of 532, 593, 753, 808, 888 though $YVO_{4}$ single crystal had a broad transmittance at wavelength ranging from 340 to 1000nm. Also, Nd:$YVO_{4}$ single crystals had emissions of energy at range of 800~900 nm in photoluminescence (PL) spectrum.

• Digital Contents
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• no.10 s.137
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• pp.162-163
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• 2004

지난해 기업용 솔루션 업계의 최대 이슈로 급부상했던 BI(비즈니스인텔리전스)가 올해는 DW(데이터웨어하우스)라는 오랜 둥지에서 벗어나 독자적인 애플리케이션 영역으로 빠르게 성장하고 있다. 반면 ETL(데이터 추출 변환 로딩)툴을 중심으로 하는 데이터 통합 솔루션의 영역은 BI를 벗어난 영역으로의 확장을 강조하고 있고 그 부분이 경쟁력을 결정하는 핵심 포인트가 되고 있다. 최근 데이터통합 전문업체로 위상을 강화하고 있는 한국어센셜소프트웨어를 들러봤다.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.30-35
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• 1996

Calcite(CaCO3) single crystals were grown hydrothermally and transmittance of as grown crystals was measured. Instead of platinium, teflon was lined onto the wall of autoclave to prevent the corrosion of autoclave wall by acidic NH4Cl solution. Spontaneous nucleation and growth of calcite crystal on teflon was reduced considerably by addition of NaCl and /or CH3COOH and applying low temperature gradient. When the temperature gradient exceeded to a few degrees from the critical temperature gradient(6-7℃), spontaneous nucleation and growth was rapidly increased in any hydrothermal solutions. Precise temperature control is thought to be the most important factor for the growth of calcite single crystal by hydrothermal technique. As grown calcite single crytal showed high transmittance compared to natural one by UV-visible analysis.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.1
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• pp.33-40
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• 2002

In this paper, we proposed a lossless compression algorithm of medical images which is essential technique in picture archive and communication system. Mammographic image and magnetic resonance image in among medical images used in this study, proposed a region growing segmentation algorithm for compression of these images. A proposed algorithm was partition by three sub region which error image, discontinuity index map, high order bit data from original image. And generated discontinuity index image data and error image which apply to a region growing algorithm are compressed using JBIG(Joint Bi-level Image experts Group) algorithm that is international hi-level image compression standard and proper image compression technique of gray code digital Images. The proposed lossless compression method resulted in, on the average, lossless compression to about 73.14% with a database of high-resolution digital mammography images. In comparison with direct coding by JBIG, JPEG, and Lempel-Ziv coding methods, the proposed method performed better by 3.7%, 7.9% and 23.6% on the database used.

• 월간 기계설비
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• s.240
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• pp.50-64
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• 2010

'그린'은 미래를 이끌어갈 신성장동력 즉, 향후 녹색성장을 주도할 핵심이다. 국내 주요 건설사들 역시 탄소저감기술 '그린'에 대한 영역확보와 시장선점에 사활을 걸면서 그린 기술을 접목한 첨단주택을 발빠르게 선보이고 있으며 특성화를 통해 브랜드의 친환경적 이미지를 높이고 있다. 정부도 저탄소 녹색성장을 추진하면서 '그린홈 보급사업'에 적극 나서고 있다. 바야흐로 친환경 녹색성장 시대에 접어든 것이다. 본지는 주택시장을 중심으로 빠르게 보급되고 있는 '그린홈'에 대해 알아본다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.225-228
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• 2005

We have grown the long persistent $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ phosphor single crystal by Verneuil method. The obtained single crystals were long persistent phosphorescence peaking at ${\lambda}=520nm$ with a size of about 5 mm diameter, 55 mm length. The melting temperature of $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ measured $T_{mp}=1968^{\circ}C$. The optimum composition was $SrCO_3:Al(OH)_3:Eu_2O_3:Dy_2O_3$ = 1 : 2 : 0.015 : 0.02. Flow rate of $H_2:O_2$ is about 4 : 1. Growthing rate is about 5 mm/hr. The spectra of the phosphorescence from the crystals are quite similar to those obtained with sintered powders used for luminous pigments. The crystalline structure of long persistent $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ phosphor single crystal was determined by X-ray diffraction.

• Journal of the Korean Vacuum Society
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• v.9 no.2
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• pp.172-178
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• 2000

We developed the model equations to investigate the particle movement and growth theoretically in a-Si plasma CVD reactor, where those particles act as the source of contamination. We included the effects of fluid convection, particle diffusion and external forces (ion drag force, electrostatic force and gravitational force) onto the particles to analyze the movements of particles in plasma reactor. Taking into account the particle charge distribution, the particle growth by coagulation between the charged particles was investigated. Most of those particles are located in the region near the sheath boundaries by the balance between the ion drag and electrostatic forces. The particle concentrations in the sheath region and in the bulk plasma region are almost zero. The sizes of the predator particles increase with time by the coagulation with protoparticles and, as a result, the surface area and the average charge of predator particles also increase with time.