• 비파괴검사학회지
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• 제32권3호
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• pp.296-301
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• 2012

This paper describes an analytic method for infrared thermography to detect surface cracks in thin plates. Traditional thermographic method uses the spatial contrast of a thermal field, which is often corrupted by noise in the experiment induced mainly by emissivity variations of target surfaces. This study developed a robust analytic approach to crack detection for thermography using the holomorphic function of a temperature field in thin plate under steady-state thermal conditions. The holomorphic function of a simple temperature field was derived for 2-D heat flow in the plate from Cauchy-Riemann conditions, and applied to define a contour integral that varies depending on the existence and strength of singularity in the domain of integration. It was found that the contour integral at each point of thermal image reduced the noise and temperature variation due to heat conduction, so that it provided a clearer image of the singularity such as cracks.

• 대한기계학회논문집A
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• 제25권9호
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• pp.1368-1375
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• 2001

This paper examines that it is possible to apply RWCIM for determining eigenvector coefficients associated with eigenvalues for V-notched cracks in anisotropic dissimilar materials using the complex stress function. To verify the RWCIM algorithm, two tests will be shown. First, it is performed to ascertain whether predicted coefficients associated with eigenvectors are obtained exactly. Second, it makes an examination of the state of stresses for FEM and RWCIM according to a number of eigenvectors at a location far away from the v-notched crack tip.

• 대한기계학회논문집
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• 제8권3호
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• pp.232-240
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• 1984

본 논문에서는 Stern이 제시한 경로적분식을 기본방정식으로 하여 예리한 임 의 노치내각을 가진(크랙의 경우 0˚), 즉 r$^{.lambda.}$ 형태의 특이점을 포함한 모우드-I 및 II 응력확대계수를 위한 특성해 및 보조해를 규정하고 선택모형문제로 예리한 노치 내각을 달리한 대칭 하중의 인장문제와 끝단 전단력하중하의 일단 고정보의 비대칭문 제의 응력확대계수를 기존의 재래식 유한요소법과 결합하여 계산하였다. 또한 각각 의 경우 적분경로 및 요소분할을 달리하여 수치해의 안정성 및 경로 독립성을 검토하 였다.

• 대한기계학회논문집
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• 제13권3호
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• pp.479-489
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• 1989

본 논문에서는 Ｊ$_{1}$,Ｊ$_{2}$ 적분과 Ｋ$_{I}$,Ｋ$_{II}$ 사이의 완전한 관계를 좁은 직사각형 경로를 택하여 간판하게 유도하였다. 그리고 유한요소의 해로 Ｊ$_{2}$적분을 효율적으로 계산하는 방법을 제시하였다.이미 해가 존재하는 문제 를 본 방법으로 다루어 그 결과를 비교하였고 일방향(unidirectional) 적층판 cantil- ever 평판 내의 single edge crack에 대한 해를 제시하였다.

• Advances in Computational Design
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• 제9권1호
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• pp.73-80
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• 2024

The aim of this paper is to remove the rigid body motion in the interior boundary value problem (BVP) of plane elasticity by solving the interior and exterior BVPs simultaneously. First, we formulate the interior and exterior BVPs simultaneously. The tractions applied on the contour in two problems are the same. After adding and subtracting the two boundary integral equations (BIEs), we will obtain a couple of BIEs. In the coupled BIEs, the properties of relevant integral operators are modified, and those integral operators are generally invertible. Finally, a unique solution for boundary displacement of interior region can be obtained.

• 충청수학회지
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• 제23권4호
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• pp.679-689
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• 2010

By developing and using certain operators like those initiated by Burchnall-Chaundy, the authors aim at investigating several decomposition formulas associated with the $Kamp{\acute{e}}$ de $F{\acute{e}}riet$ function $F_{2:0;0}^{0:3;3}$ [x, y]. For this purpose, many operator identities involving inverse pairs of symbolic operators are constructed. By employing their decomposition formulas, they also present a new group of integral representations of Eulerian type for the $Kamp{\acute{e}}$ de $F{\acute{e}}riet$ function $F_{2:0;0}^{0:3;3}$ [x, y], some of which include several hypergeometric functions such as $_2F_1$, $_3F_2$, an Appell function $F_3$, and the $Kamp{\acute{e}}$ de $F{\acute{e}}riet$ functions $F_{2:0;0}^{0:3;3}$ and $F_{1:0;1}^{0:2;3}$.

• 전자공학회논문지B
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• 제28B권7호
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• pp.578-589
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• 1991

In this paper, there is proposed a novel concept of Incremintal Circle Transform which can describe the boundary contour of a two-dimensional object without object without occlusions. And a pattern recognition algorithm to determine the posture of an object is developed with the aid of line integral and similarity transform. Also, It is confirmed via experiments that the algorithm can find the posture of an object in a very fast manner independent of the starting point for boundary coding and the position of the object.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.917-922
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• 1990

Pattern classification is an essential step in automatic robotic assembly which joins together finite number of seperated industrial parts. In this paper, a fast and systematic algorithm for classifying occlusion-free objects is proposed, using the notion of incremental circle transform which describes the boundary contour of an object as a parametric vector function of incremental elements. With similarity transform and line integral, normalized determinant curve of an object classifies each object, independent of position, orientation, scaling of an object and cyclic shift of the stating point for the boundary description.

• 호남수학학술지
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• 제41권1호
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• pp.1-17
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• 2019

The aim of this paper is to establish certain integrals involving product of the Aleph function with exponential function and multi Gauss's hypergeometric function. Being unified and general in nature, these integrals yield a number of known and new results as special cases. For the sake of illustration, twelve corollaries are also recorded here as special case of our main results.

• 전산구조공학
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• 제8권4호
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• pp.137-148
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• 1995

이차원 선형탄성파괴역학 문제에서 인장모우드 상태의 응력확대계수를 명료하게 산정할 수 있는 독립적 적분경로에 근거를 둔 새로운 J-적분 균열모델이 제안되었다. 이 방법은 p-수렴 개념에 기초를 두며 기존의 유한요소 컴퓨터코드에 쉽게 적용할 수 있다. 본 연구에서는 균열선단에서의 응력상태가 조사되었으며, 균열선단으로부터 떨어진 정규거리로 표현되는 서로 다른 적분경로에 따라 J-적분치가 유한요소해석시 Rice의 이론처럼 경로에 독립적인 해를 얻을 수 있는지 분석되었다. 세가지 수치예제인 중앙균열판, 일변균열판과 양변균열판과 양변균열판의 p-수렴 해석결과가 종래의 h-수렴법에 의한 해석결과와 비교되었으며, 또한 이 결과는 제안된 방법의 정확성과 수치적 안정성을 보여주고 있다.