• 대한기계학회논문집
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• 제16권12호
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• pp.2226-2240
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• 1992

본 연구에서는 이방성체에 대한 구체적인 코스틱스 실험법을 확립하기 위하여 다음과 같은 연구를 수행 하였다. 첫째, 이방성체에 대한 코스틱스상 및 초기곡선의 사상방정식을 기하광학 및 Sih의 응력장을 이용하여 구하고, 이 식에 의한 이론상을 여러가지 경계조건하에서 컴퓨터 그래픽 하여 유도한 사상방정식의 타당성을 검토 하 였다.둘째, 본 논문에서 개발한 두 가지 종류의 직교이방성체를 사용하여 실험을 수행하고 실험에 의한 코스틱스상을 이론상과 비교, 검토 하였다.셋째, 이방성체의 코스틱스상으로부터 응력확대계수를 구하는 방법을 제시하고 이 방법을 실제 시편에 적용하여 신뢰 할수 있는 결과를 얻는 초기곡선의 범위를 결정 하였다. 그리고 이 범위에서 구한 응력확대 계수 값을 경계요소법을 이용한 변위외삽법에 의한 결과와 비 교함으로써 본 논문에서 제시하는 방법이 이방성체의 응력확대계수를 구하는 한 방법 으로 유효하게 사용될 수 있음을 밝혔다.

• 대한기계학회논문집A
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• 제25권4호
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• pp.734-740
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• 2001

In this paper the stress intensity factor under uniform pressure in the arbitrarily-shaped plane crack configuration transformed elliptic crack by Mobius mapping are determined. Using Dysons formula Boussinesq-Papkovich potentials for mode I deformation are constructed. In the example the stress intensity factors are approximately calculated by least square method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.117-122
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• 2000

In this paper the stress intensity factor under uniform pressure in the arbitrarily-shaped plane crack configuration transformed elliptic crack by Mobius mapping are determined. Using Dyson's formula Boussinesq-Papkovich potentials for mode I deformation are constructed. In the example the stress intensity factors are approximately calculated by least square method.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.1922-1927
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• 2003

Nonlinear normal mode (NNM) vibration, in a nonlinear dual mass Hamiltonian system, which has 6$\^$th/ order homogeneous polynomial as a nonlinear term, is studied in this paper. The existence, bifurcation, and the orbital stability of periodic motions are to be studied in the phase space. In order to find the analytic expression of the invariant curves in the Poincare Map, which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space, Whittaker's Adelphic Integral, instead of the direct integration of the equations of motion or the Birkhoff-Gustavson (B-G) canonical transformation, is derived for small value of energy. It is revealed that the integral of motion by Adelphic Integral is essentially consistent with the one obtained from the B-G transformation method. The resulting expression of the invariant curves can be used for analyzing the behavior of NNM vibration in the Poincare Map.

• 정보통신설비학회논문지
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• 제10권1호
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• pp.7-13
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• 2011

Matrix multiplication is a fundamental operation of linear algebra and arises in many areas of science and engineering. This paper introduces an efficient parallel matrix multiplication scheme on N ${\times}$ N mesh-connected SIMD array processor, called multiple hierarchical SIMD architecture (HMSA). The architectural characteristic of HMSA is the hierarchically structured control units which consist of a global control unit, N local control units configured diagonally, and $N^2$ processing elements (PEs) arranged in an N ${\times}$ N array. PEs are communicating through local buses connecting four adjacent neighbor PEs in mesh-torus networks and global buses running across the rows and columns called horizontal buses and vertical buses, respectively. This architecture enables HMSA to have the features of diagonally indexed concurrent broadcast and the accessibility to either rows (row control mode) or columns (column control mode) of 2D array PEs alternately. An algorithmic mapping method is used for performance evaluation by mapping matrix multiplication on the proposed architecture. The asymptotic time complexities of them are evaluated and the result shows that paralle matrix multiplication on HMSA can provide significant performance improvement.

• Smart Structures and Systems
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• 제14권4호
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• pp.699-718
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• 2014

The indirect displacement estimation using acceleration and strain (IDEAS) method is extended to various types of beam structures beyond the previous validation on the prismatic or near-prismatic beams. By fusing different types of responses, the IDEAS method is able to estimate displacements containing pseudo-static components with high frequency noise to be significantly reduced. However, the concerns to the IDEAS method come from possible disagreement of the assumed sinusoidal mode shapes to the actual mode shapes, which allows the IDEAS method to be valid only for simply-supported prismatic beams and limits its applicability to real world problems. In this paper, the extension of the IDEAS method to the general types of beams is investigated by the mathematical formulation of the modal mapping matrix only for the monitored substructure, so-called monitoring span. The formulation particularly considers continuous and wide beams to extend the IDEAS method to general beam structures that reflect many real bridges. Numerical simulations using four types of beams with various irregularities are presented to show the effectiveness and accuracy of the IDEAS method in estimating displacements.

• 한국지진공학회논문집
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• 제5권3호
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• pp.57-64
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• 2001

보강된 판 및 쉘구조의 동적 비선형해석을 수행하기 위하여, 유한회전을 고려한 변형된 쉘유한요소를 이용하여 total Lagrangian formulation이 제시된다. 전단구속 (shear locking) 현상과 가상의 제로에너지 모우드를 동시에 제거하기 위하여 가정변형도 개념을 채용한다. 탄소성해석에서는 return mapping 미해rithm이 쉘구조의 붕괴 해석에 적용된다. Newmark 직접적분법을 사용하여 동하중 및 지진하중을 받는 쉘구조의 동적 비선형해석 결과를 제시한다.

• 한국전자파학회논문지
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• 제15권10호
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• pp.944-951
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• 2004

본 논문에서는 등각사상 법을 이용해 접지 면에 어퍼처를 갖는 차폐된 마이크로스트립 선로의 특성임피던스 및 유효 유전 상수 등을 계산하는 방법을 제안하였다. 이 방법은 닫힌 형태의 공식을 제시하기 때문에 따로 어떠한 수치해석 방법을 쓰지 않고도 선로 파라미터들을 계산할 수 있다는 장점이 있다. 먼저 신호가 마이크로스트립 모드(Quasi-TEM)로 진행한다고 가정하고 차폐된 선로를 세 부분으로 나누어 정전 용량을 계산하고 계산된 부분별 정전 용량들을 이용해 임피던스 및 유효 유전상수를 계산하였다. HFSS 시뮬레이션 결과, 계산 결과가 시뮬레이션 결과와 오차범위 $5\%$ 이내로 거의 일치함을 알 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제21권10호
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• pp.11-19
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• 2016

The size of a display is large, The form becoming various of that do not apply to previous methods of gaze tracking and if setup gaze-track-camera above display, can solve the problem of size or height of display. However, This method can not use of infrared illumination information of reflected cornea using previous methods. In this paper, Robust pupil detecting method for eye's occlusion, corner point of inner eye and center of pupil, and using the face pose information proposes a method for calculating the simply position of the gaze. In the proposed method, capture the frame for gaze tracking that according to position of person transform camera mode of wide or narrow angle. If detect the face exist in field of view(FOV) in wide mode of camera, transform narrow mode of camera calculating position of face. The frame captured in narrow mode of camera include gaze direction information of person in long distance. The method for calculating the gaze direction consist of face pose estimation and gaze direction calculating step. Face pose estimation is estimated by mapping between feature point of detected face and 3D model. To calculate gaze direction the first, perform ellipse detect using splitting from iris edge information of pupil and if occlusion of pupil, estimate position of pupil with deformable template. Then using center of pupil and corner point of inner eye, face pose information calculate gaze position at display. In the experiment, proposed gaze tracking algorithm in this paper solve the constraints that form of a display, to calculate effectively gaze direction of person in the long distance using single camera, demonstrate in experiments by distance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.498-504
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• 2002

Vibration beat phenomenon is theoretically investigated on a slightly asymmetric cylindrical shell, which is a simplified model of Korean bell. Mode pairs of the slightly asymmetric shell are obtained by receptance analysis and impulse response of the shell is derived using modal expansion and Laplace transform. Based on the impulse response model, beat mapping method is proposed to explain the reason that the beat of a bell vibration shows periodic distribution on the circumference. Beat characteristics of King Song-Dok Bell are explained in detail using the beat map and the measured modal data.