• Title/Summary/Keyword: 흡수 경계조건

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Region Growing Technique Using Threshold for Cell Image Segmentation (세포 영상 영역 분할을 위한 Threshold를 적용한 Region Growing 기법)

  • 강미영;하진영;김호성;김백섭
    • Proceedings of the Korean Information Science Society Conference
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    • 1999.10b
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    • pp.533-535
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    • 1999
  • 자궁경부진 세포인식 시스템에 있어서 가장 중요한 것이 영상처리를 이용하여 세포핵과 세포질을 추출하여 세포의 형태적인 정보를 알아내는 과정이다. 기존의 전역 thresholding 기법이나 region growing의 경우는 pap smear 검사를 통해 얻어진 세포 영상을 분할할 수 있는 region growing 기법을 제안한다. 제안된 region growing 기법은 초기에 seed를 검출할 때 local threshold growing 기법을 제안한다. 제안된 region growing 기법은 초기에 seed를 검출할 때 local threshold 개념을 도입하여 seed의 검출을 고르게 하고, 2가지 확장 조건을 사용하여 영역을 확장한다. 첫 번째 확장 조건은 비정상 세포나 artifact가 많아서 어둡게 나타나는 영상이나 세포질과 배경의 경계가 뚜렷하지 않아서 세포질의 구별이 어려운 영상의 영역 분할이 가능하도록 그 특성을 반영하고, 두 번째 조건은 세포가 흡수하는 빛의 양이 일정하다는 가정으로 영상에서의 지역 특성(gray level, color 등을 반영한다. 제안된 기법은 정상세포 영상뿐만 아니라 비정상 세포 영상에 대하여 over-segment나 under-segment하는 경우를 줄여서 영역 분할에 좋은 결과를 보인다.

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Structural Analysis for the Container-Shaped Type A Package of Radioactive Materials (컨테이너형태의 방사성물질 A형 운반용기에 대한 구조해석)

  • 이영신;이호철;정성환;이흥영;김용재
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.2
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    • pp.143-150
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    • 2001
  • 원자력발전소의 1차 계통에서 오염된 장비들을 취급이 용이하고 안전하게 운반하기 위한 운반용기는 내부의 방사성 물질에 대한 방사능 평가에 의하여 방사성물질 A형 운반용기로 분류된다. 방사성물질 A형 운반용기는 IAEA Safety Standard Series No. ST-1 및 국내 원자력법 등 관련규정의 기술기준을 만족하여야 하는데, 운반용기는 중량에 따라 0.3∼1.2m의 높이에서 소성이 일어나지 않는 단단한 바닥면으로 가장 심각한 손상을 주는 방향으로 낙하시키는 정상운반조건(normal transport conditions)에 대하여 구조적 건전성을 유지하여야 한다. 여기서는 ABAQUS/Explicit 코드를 이용하여 컨테이너형태의 A형 운반용기에 대하여 최대손상이 야기되는 0.9m 경사낙하조건에 대한 3차원 충격해석을 수행하고 구조적 건전성을 평가하였는데, 운반용기는 경사낙하시 코너피팅(corner fitting)의 분쇄(crush)에 의하여 대부분의 충격을 흡수하였으며 운반용기의 격납경계는 구조적 건전성을 유지하였다.

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Analysis of Hydraulic behavior in Unsaturated Soil Slope for the Boundary Condition and Hysteresis of SWCC (경계 조건과 불포화 함수 특성 곡선의 이력에 따른 불포화 토사 사면의 수리적 거동 분석)

  • Lee, Eo-Ryeong;Park, Hyun-Su;Park, Seong-Wan
    • Journal of the Korean Geotechnical Society
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    • v.39 no.1
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    • pp.15-25
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    • 2023
  • Recent weather changes have led to an increase in heavy rainfall resulting in frequent large-scale slope failures. To minimize damage to life and property, a measurement system is used in slope failure warning systems. However, understanding the slope failure behavior is difficult as the measurement system only measures a specific point. Therefore, numerical analysis must be p erformed with the measurement system. The soil water characteristic curve (SWCC) drying curve and boundary conditions that consider evapotranspiration and precipitation have been applied to numerical analysis, but the hysteresis of SWCC affects the numerical analysis results. To address this, a new evapotranspiration calculation method is proposed and applied to boundary conditions, and the measurement data are compared with the results of the numerical analysis. This method takes into account the different infiltration behaviors on evapotranspiration according to the drying and wetting curves of the SWCC, and allows for a more rational prediction of water movement on unsaturated slopes.

Prediction of Temperature Distribution for Heat Treatment of 2.5% C-15% Cr Sleeve Casting Roll for Coke Biquette (2.5% C-15% Cr 성형탄 슬리이브 캐스팅로울의 열처리에 대한 온도 분포예측)

  • 하만영;윤영환
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.3
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    • pp.408-418
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    • 1986
  • 본 연구에서는 표면은 단단하고 내면은 강인한 조직을 얻기위하여 대형 성형 탄 로울에 대하여 노에서의 급속가열 및 대기 상태에서의 자연냉각의 열처리가 수행 되어진다. 급속가열 및 냉각시 성형탄 로울 내부의 온도 분포 예측을 위하여 대류 및 복사 열전달 경계조건을 가지는 1차원 비정상 열전도 방정식이 유한 차분법을 사 용하여 해석되어졌다. 여기서 급속가열시 연소가스로 부터 기체복사에 의하여 성 형탄 로울의 바깥표면을 통하여 흡수되는 열량은

Diffraction Characteristics in Wireless Environment by using the FDTD Method (FDTD법을 이용한 무선 환경에서의 회절 특성)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.6
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    • pp.1259-1265
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    • 2013
  • In wireless environment such as wireless LAN, proper location of wireless LAN AP allows us to take an effective coverage to provide good wireless communication service. To simulate wireless environment, FDTD formulation is introduced and Gaussian pulse injection in grid space is considered to be replaced wireless LAN AP. So structural effect corresponding to location of arbitrary obstacle must be considered, and its received gain is estimated. An obstacle in scattering field should be modeled to be conductor and concrete wall and its diffraction effect for some cross wall is evaluated between transmitter and receiver point.

Behavior of Spin Waves Excited in Magnetic Thin Film (자성 박막에서 여기되는 스핀파 거동)

  • 한기평;손영준;백문철;조경익
    • Journal of the Korean Magnetics Society
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    • v.10 no.2
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    • pp.86-92
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    • 2000
  • The spin wave absorption spectra are obtained by a simultaneous solution of the Maxwell equation and the Gilbert equation considering the boundary condition of electromagnetic wave and magnetization in the film surfaces. The physical parameters that influence the absorption energy are thickness, exchange stiffness constant, surface magnetic anisotropy, magnetization. damping factor, electric resistivity of the thin film. We investigated how these parameters affect the resonance field, the linewidth and the intensity of the spin wave spectrum.

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Diffraction Characteristics of Obstacle using the FDTD method (FDTD법을 이용한 장벽에 의한 회절 특성)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2013.05a
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    • pp.49-50
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    • 2013
  • In wireless environment, to provide more efficient service area is need to maintain proper location of wireless LAN AP. Since structural effect corresponding to location of arbitrary scatterers must be considered. Using FDTD method, an obstacle in scattering field should be considered and its diffraction effect for some cross wall is estimated between transmitter and receiver point.

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Radiation Characteristic Analysis of Fresnel Zone Plate Lens Array (프레넬 존 플레이트 렌즈 배열의 방사특성 해석)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.53-54
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    • 2014
  • By using geometrical structure of Fresnel lens, it can be applied with receiver antenna and geodetic system. In this paper, radiation pattern from fresnel lens array of Soret type is calculate by the FDTD method. For simplicity, fresnel lens should be located linearly and considered to be dielectric rod with a relative permittivity.

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Characteristics of Fresnel Lens Array with Reflected Plate (반사판 구조를 가지는 프레넬 렌즈의 특성)

  • Kim, Tae Yong;Lee, Hoon-Jae
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.43-44
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    • 2014
  • By using geometrical structure of Fresnel lens, it can be applied with receiver antenna and geodetic system. In this paper, we consider Soret typed fresnel lens with reflected plate and its focusing gain characteristics is calculated by the FDTD method.

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Impact characteristics of the stainless sheet on the fixed boundary condition (고정형 조건에서의 스테인레스 강판의 충격 특성)

  • Ahn, Dong-Gyu;Moon, Kyung-Je;Jung, Chang-Gyun;Han, Gil-Young;Yang, Dong-Yol
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.48-53
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    • 2007
  • The objective of this paper is to investigate the influence of impact conditions on the impact characteristics of the stainless sheet for the case of the fixed boundary conditions. In order to examine impact characteristics of the sheet, three-dimensional finite element analyses and impact tests have been performed. High speed tensile tests have been carried out to obtain strain-stress relationships including the effects of the strain rate. In order to improve an accuracy of the FE analysis, the hyper-elastic model and the damping factor have been introduced. The results of the FE analyses and the impact tests have been shown that the diameter of the impact head does not affect the absorption energy of the stainless sheet. In addition, it has been shown that the absorption rate of energy maintains almost $82.5\;\sim\;83.5\;%$ irrespective of the impact energy level and the diameter of the impact head. From the results of FE analyses, the variation of stress and strain energy in the stainless sheet has been quantitatively examined.

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