• 스마트미디어저널
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• 제1권4호
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• pp.27-34
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• 2012

In this paper, a novel text binarization is presented that can deal with some complex conditions, such as shadows, non-uniform illumination due to highlight or object projection, and messy backgrounds. To locate the target text region, a focus line is assumed to pass through a text region. Next, connected component analysis and stroke width estimation based on location information of the focus line is used to locate the bounding box of the text region, and each box of connected components. A series of classifications are applied to identify whether each CC(Connected component) is text or non-text. Also, a modified K-means clustering method based on an HCL color space is applied to reduce the color dimension. A text binarization procedure based on location of text component and seed color pixel is then used to generate the final result.

• 대한조선학회지
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• 제7권1호
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• pp.13-26
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• 1970

An elastic plate bar jointed to a rigid bar is considered. The bar is subjected to uniform axial tension. A theoretical approximate solution is obtained in an infinite hyperbolic series form and some numerical results for various Poisson's ratios are presented. A rubber plate joined to a strong wooden plate has been tested to obtain an experimental data and the results are compared with theoretical ones. Two values for vertical displacements are in good agreement but it is not satisfactory for horizontal displacements. The conclusion arrived at are as follow : The natures of stress distributions and deformed shapes given by above theoretical solution are compatible in mechanical sense. The magnitudes of stress and displacement components would not be reliable for exact works. A sharp shear stress concentrations are detected at the both ends of the joint.

• 한국전자파학회논문지
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• 제10권3호
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• pp.412-418
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• 1999

기하학적 균일 회절 이론 (Uniform Geometrical Theory of Diffraction)을 이용하여 옵\ulcorner 파라볼릭 안테나의 산란 특성을 분석하였다. 먼저 파추적법(Ray Tracing)에 의하여 음영경계를 나눈후, 각 영역에 존재하는 반사파와 회절파를 기하학적 균일 회절 이론을 이용해 구하였다. 또한, 옵\ulcorner 파라볼릭 안테나의 모서리(edge)의 형태가 전자파의 산란 특성에 미치는 영향을 알아보기 위해 knife 모서리인 경우와 원형 캡을 부착한 경우를 분석하여 비교하였다.

• 한국해양공학회지
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• 제22권3호
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• pp.89-95
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• 2008

Fatigue cracked components often needs to be repaired during service. Standard repair schemes involve strengthening the component by connecting reinforcing members by means of rivets or welding by reducing the crack-tip stress intensity factors. Recent technological advances in fiber reinforced composite materials and adhesive bonding have led to the development of efficient repair schemes. In this study, the influence of various shape parameters on fatigue crack growth in the CCT type uniform thickness plates and the thin-ta-thick type stiffened panels repaired with woven fabric type Kevlar-Epoxy composite patch are studied experimentally.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.188-190
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• 1999

This paper analyzed the static torque of SRM according to the variation of airgap length using Finite Element Method. The normal and tangential components of flux density are analyzed at uniform airgap field which sap length is 0.3[mm] and nonuniform airgap which gap lengths are 0.2-0.4[mm] and 0.4-0.2[mm]. Also their static torques were simulated by using Virtual Work Principle. We expect that their parameters will help for the design of Switched Reluctance Motor.

• Structural Engineering and Mechanics
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• 제55권1호
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• pp.29-46
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• 2015

A three-dimensional (3-D) method of analysis is presented for determining the natural frequencies of a truncated shallow and deep conical shell with linearly varying thickness along the meridional direction free at its top edge and clamped at its bottom edge. Unlike conventional shell theories, which are mathematically two-dimensional (2-D), the present method is based upon the 3-D dynamic equations of elasticity. Displacement components $u_r$, $u_{\theta}$, and $u_z$ in the radial, circumferential, and axial directions, respectively, are taken to be periodic in ${\theta}$ and in time, and algebraic polynomials in the r and z directions. Strain and kinetic energies of the truncated conical shell with variable thickness are formulated, and the Ritz method is used to solve the eigenvalue problem, thus yielding upper bound values of the frequencies by minimizing the frequencies. As the degree of the polynomials is increased, frequencies converge to the exact values. Convergence to four-digit exactitude is demonstrated. The frequencies from the present 3-D method are compared with those from other 3-D finite element method and 2-D shell theories.

• 한국신뢰성학회지:신뢰성응용연구
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• 제6권1호
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• pp.51-61
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• 2006

Failure analyses were conducted on a crank shaft and a chock liner by using X-ray diffraction, optical microscopy and SEM/EDS techniques. In the crank shaft, a crack developed where a maximum tensile stress coincided with band structure formed by hot forging. The maximum tensile stress was observed to originate from volume expansion during high frequency induction heat treatment and the band structure to develop between upper and lower dies during hot forging. In the chock liner, the wear mechanism varied with the chemical affinity and hardness of liner material relative to friction pair of housing liner. Brass of low chemical affinity and hardness compared to housing liner showed uniform adhesive wear. STS 304 and STS 420J2 of high chemical affinity showed galling and scoring respectively.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.806-818
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• 2006

The shear spinning process, where the plastic deformation zone is localized in a very small portion of the workpiece, shows a promise for increasingly broader application to the production of axially symmetric parts. In this paper, the three components of working force are calculated by the newly proposed deformation model in which the spinning process is understood as shearing deformation after uniaxial yielding by bending, and shear stress, $\tau_{rz}$ becomes $\kappa$, yield limit in pure shear, in the deformation zone. The tangential forces are first calculated and the feed forces and the normal forces are obtained by the assumption of uniform distribution of roller pressure on the contact surface. The optimum contact area is obtained by minimizing the bending energy required to get the assumed deformation of the blank. The calculated forces are compared with experimental results. A comparison shows that theoretical prediction is reasonably in good agreement with experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.1010-1014
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• 2001

A severe strip vibration in continuous galvanizing line facilities of the steel companies has sometimes occurred due to the exceeding wearing of the roll bush and bearing. This vibration brings on the lack of uniform coating thickness in steel plate. As a result, the total maintenance and product costs in this factory are increased by the shortage of operation time for the replacement of bush, bearings and these components. In this study, the vibration characteristics of this strip are investigated by the FEM using ANSYS. Also the vibration measurement of strip and its structure performed by the laser Doppler vibrometer(LDV) and accelerometers are compared to theoretical analysis results.

• Steel and Composite Structures
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• 제48권5호
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• pp.583-597
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• 2023

This paper introduces a novel approach to multi-material topology optimization (MTO) targeting in-plane bi-directional functionally graded (IBFG) non-uniform thickness Reissner-Mindlin plates, employing an alternative active phase approach. The mathematical formulation integrates a first shear deformation theory (FSDT) to address compliance minimization as the objective function. Through an alternating active-phase algorithm in conjunction with the block Gauss-Seidel method, the study transforms a multi-phase topology optimization challenge with multi-volume fraction constraints into multiple binary phase sub-problems, each with a single volume fraction constraint. The investigation focuses on IBFG materials that incorporate adequate local bulk and shear moduli to enhance the precision of material interactions. Furthermore, the well-established mixed interpolation of tensorial components 4-node elements (MITC4) is harnessed to tackle shear-locking issues inherent in thin plate models. The study meticulously presents detailed mathematical formulations for IBFG plates in the MTO framework, underscored by numerous numerical examples demonstrating the method's efficiency and reliability.