• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.155-159
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• 2000

YBCO step-edge dc SQUID magnetometers on sapphire substrates have been fabricated. CeO2 buffer layer and YBCO films were deposited in situ on the low angle (${\sim}$35$^{\circ}$) steps formed on the sapphire substrates. Typical 5-${\mu}$m-wide junction has R$_n$ of 5 ${\omega}$ and I$_c$ of 50 ${\mu}$A with large I$_c$R$_n$ product of 250 ${\mu}$V at 77K. According to applied bias current, depth of voltage modulation was changed and maximum voltage was measured 16 ${\mu}$V. Field noise of do SQUID was measured 100${\sim}$300 fT/${\surd}^{Hz}$ in the 1 $^{kHz}$, and about 1.5 pT/${\surd}^{Hz}$ in the 1/f region. For ac bias reversal method, field noise was decreased in the 1/f region. The QRS peak of magnetocardiogram was measured 50 pT in the magnetically shielded room.

• 대한의용생체공학회:의공학회지
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• 제17권1호
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• pp.109-120
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• 1996

Cardiac function is evaluated quantitatively using angiographic images via the analysis of the shape change or the heart wall boundaries. To kin with, boundary defection or ESLV(End Systolic Lert Ventricular) and EDLV(End Diastolic Left Ventricular) is essential for the quantitative analysis of cardiac function. The boundary detection methods proposed in the past were almost semi-automatic. Intervention by a knowledgeable human operator was still required Of con, manual tracing of the boundaries is currently used for subsequent analysis and diagnosis. This method would not cut excessive time, labor, and subjectivity associated with manual intervention by a human operator. EDLV images have noncontiguous and ambiguous edge signal on some boundary regions. In this paper, we propose a new method for automated detection of boundaries in noncontiguous and ambiguous EDLV images. The boundary detection scheme which based on a priori knowledge information is divided into two steps. The first step is to detect the candidate edge points of EDLV using ESLV boundaries. The second step is to correct detected boundaries of EDLV using the LV shape. We developed the algorithm of modifying EDLV boundaries defined adaptive modifier. We experimented the method proposed in this paper and compared our proposed method with the manual method in detecting boundaries of EDLV. In the areas within estimated boundaries of EDLV, the percentage of error was about 1.4%. We verified the useflilness and obtained the satisfying results througll the experiments of the proposed method.

• IUGG한국위원회:학술대회논문집
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• IUGG한국위원회 2003년도 정기총회 및 학술발표회
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• pp.18-18
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• 2003

Three-dimensional finite-difference simulation of earthquake ground motion is performed using a locally variable time-step (LVTS) scheme matching with discontinuous grids. Discontinuous grids in three directions and extension of the discontinuous grids' boundary to the free-surface in the LVTS scheme minimize the cost of both the computational memory and the CPU time for models like the localized sedimentary basin. A simplified model of sedimentary basin is dealt to show the feasibility and efficiency of the LVTS scheme. The basin parameters are examined to understand the main characteristics on ground-motion response in the basin. The results show that the seismic energy is concentrated on a marginal area of the basin far from the source. This focusing effect is mainly due to the constructive interference of the direct S-wave with the basin-edge induced surface waves. The ground-motion amplification over the deepest part of the basin is relatively lower than that above the shallow basin edge. Therefore the ground-motion amplification may be more related to the source azimuth or the direction of the incident waves into the basin rather than the depth of it.

• Structural Engineering and Mechanics
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• 제73권4호
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• pp.455-462
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• 2020

The hybrid method using the extended finite element method (XFEM) and the forward Euler approach is widely employed to predict the fatigue life of plate structures. Due to the accuracy of the forward Euler approach is determined by a small step size, the performance of fatigue life prediction of the hybrid method is not agreeable. Instead the forward Euler approach, a prediction method using midpoint method and support vector regression (SVR) is presented to evaluate the stress intensity factors (SIFs) and the fatigue life. Firstly, the XFEM is employed to calculate the SIFs with given crack sizes. Then use the history of SIFs as a function of either number of fatigue life cycles or crack sizes within the current cycle to build a prediction model. Finally, according to the prediction model predict the SIFs at different crack sizes or different cycles. Three numerical cases composed by a homogeneous plate with edge crack, a composite plate with edge crack and center crack are introduced to verify the performance of the proposed method. The results show that the proposed method enables large step sizes without sacrificing accuracy. The method is expected to predict the fatigue life of complex structures.

• 동아시아경상학회지
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• 제10권1호
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• pp.47-57
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• 2022

Purpose - Overall social entrepreneurship has a positive effect on the organization's C.S.R. and overall growth. This study aims to identify the effects of social entrepreneurship in startup companies on corporate social responsibility by identifying gaps in the literature and providing feasible solutions to the gaps. Research design, Data, and methodology - The qualitative content analysis that was conducted by this research takes the form of two research designs. The first step to conducting a conceptual content analysis is to choose the level of analysis, specifically words, phrases, word sense and the second step is the relational content analysis by choosing the concept to be examined, only that the analysis entails examining the relationships between concepts Result - According to the investigation of numerous previous literature review, the current authors found out total six solutions and the application of suggested solutions indicated that the use of innovative models, startup organizations can gain a competitive edge against dominant competitors in their industry of operations, Conclusion - Finally, the conclusion of this research indicates through the use of innovative solution models, startup organizations can gain a competitive edge against dominant competitors in their industry of operations and startup companies may range from an increase in reputation to growth in profitability and entrepreneurs' satisfaction.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.455-458
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• 2001

In this paper, a new license plate recognition method using the morphological size distribution functions and color images is proposed. The proposed method consists of two steps. The first step is license plate extraction process using the plate color and step edge information in the license plate. The second step is the extraction of character feature vectors using the morphological size distribution functions and character recognition process using the MLP(multilayer perceptron). By the use of morphological size distributions functions, the error that may occur during the character region extraction process is lessened and the recognition performances are improved by the decrease of feature vector dimension.

• 오토저널
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• 제12권3호
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• pp.63-70
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• 1990

In a premixed flame stabilized by a streamlined step, the flame structure and combustion characteristics were investigated to identify the effect of the pressure pulsation in a combustion air. A flame stabilizing limits, visualization, mean temperature, ion current and gas concentration (O$_{2}$, CO$_{2}$, CO, UHC) were measured. With the combustion air of higher pressure pulsation, the development of the mixing layer was fast and wide, the temperature and combustion intensity were higher at arbitrary section. But, the effect was notably decreased with X=150 mm downstream. And a first eddy formation from step edge was earlier. Thus, with the combustion air of higher pressure pulsation, high rate of heat generation was expected.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.434-440
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• 2003

The exchange of model design date among heterogeneous CAD systems is a difficult task because each system has different data structures suitable for its own functions. STEP has been able to represent product information as a common computer-interpretable form that is required to remain complete and consistent when the product informant is needed to be exchanged among different computer system. However, STEP has difficult architecture in is representing point, line, curve and vectors of element, more over it can't represent geometry data of feature based models. In this study, a structure of XML document that represents geometry data of feature based models as neutral format has been developed. To use the developed XML document, a Converter has also been developed to exchange modules so that it can exchange feature based data models among heterogeneous CAD systems. Aa for evaluation of the developed XML document and Converter, Solidworks and SolidEdge are selected.

• 전자공학회논문지
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• 제50권7호
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• pp.205-215
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• 2013

디지털 이미징 장치는 일반적으로 베이어 패턴(Bayer pattern)을 사용하며, 영상 획득 과정에서 광학적 블러(blur)에 의해 영상의 품질이 손상된다. 블러된 베이어 영상에서 고해상도 컬러 영상을 얻기 위하여, 일반적으로 컬러 보간 방법과 디블러링 방법을 독립적으로 수행한다. 하지만, 베이어 샘플링에 의한 에지 정보가 불충분하여 에지를 가로지르는 방향으로 보간 하게 되고, 이에 따라 컬러 보간 과정에서 에러가 발생한다. 이러한 에러는 디블러링 과정에서 강조되어 영상의 품질을 하락시킨다. 따라서 본 논문은 컬러 보간 방법과 결합된 디블러링 알고리즘을 제안한다. 제안하는 방법은 크게 보간 단계와 영역 결정 단계로 나눌 수 있다. 보간 단계에서는 가정된 에지 방향에 따라 보간 및 디블러링 과정을 수행하고, 영역 결정 단계에서는 각 화소 위치에서 국부 영역의 특성을 추정하고, 보간 단계에서 구한 값을 영역 적응적으로 융합한다. 또한 본 논문에서는 디블러링 성능을 향상시키기 위하여 광학적 블러와 유사한 파동 광학에 근거한 블러 모델을 기반으로 하고, 추정한 국부 영역 특성을 반영하여 디블러링 필터를 추정한다. 실험 결과를 통해 제안하는 방법이 컬러 보간 에러가 확대되는 것을 방지함을 확인할 수 있으며, 기존 방법에 비해 수치적인 면과 시각적인 면에서 뛰어난 결과를 보임을 확인 할 수 있다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.633-637
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• 2001

본 논문은 모델기반 다중이동물체 추적을 위한 모델생성 알고리즘을 제안하였다. 제안한 알고리즘은 배경영상에 이동물체가 초기 진입했을 때의 초기모델생성 단계와 이동물체 추적 단계에서의 모델 갱신 단계로 구분하였다. 초기모델생성 단계에서는 차영상과 클러스터링 기법을 이용하여 분할된 분할영상과 현재프레임 영상에 대한 윤곽선 영상과의 로직 AND 연산을 수행하여 초기모델을 생성하였다. 모델갱신 단계에서는 하우스돌프 거리(Hausdorff Distance)와 2D-Logarithmic 탐색 알고리즘을 이용하여 추적중인 이동물체의 형태변화에 적응할 수 있도록 매 프레임 마다 새로운 모델을 갱신하였다. 실험은 도로에서 주행하는 자동차를 대상으로 도_의 실험을 수행하였다. 그 결과 도로에서 주행하는 자동차의 진입방향과 추적 대상 수가 불규칙한 경우에도 모델생성이 98% 이상 이루어짐을 알 수 있었다.