• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.6
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• pp.1281-1288
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• 1994

Beams curved in plan are often designed with the circular curved member system including warping effects. In this study, the curved bridges are idealized as the circular curved member system with singly symmetric cross sections and simply supported ends. Displacement fields of them to satisfy the boundary conditions are expanded by Fourier series and the governing equation of natural frequencies of them is derived. The distributions of the characteristics of natural frequencies of them are shown according to the variations of relevant parameters-angle of intersection, curvature, and parameter of symmetry of cross section which can represent the properties of the curved bridges. A parametric study is conducted to investigate the effect of relevant parameters on natural frequencies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.47-51
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• 1993

볼랜딩 하는 것은 모든제품의 다양한 형상을 얻어내는데 필수적이라 할 수 있다. 여기에서는 볼랜딩하는 방법에 있어서 형상의 변화가 쉽고 간결하게 할 수 있는 새로운 방법으로서 교차곡선을 구한 후 교차곡선을 따라가며 꼬이지 않는 평면을 설정하여 작업자에 의하여 주어지는 반경과 조정점의 위치를 조정하는 방법으로 볼랜딩하는 방법을 제시한다. 본 논문에서는 자유곡면과 자유곡면의 볼렌딩,자유곡면과 다면체곡면의 볼랜딩하는 방법을 제시한다.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.19-21
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• 2001

본 논문은 객체의 유사성 비교를 위해 객체의 모양을 표현하는 한 가지 특징인 윤곽선상의 우세 점들을 찾는 재귀적 윤곽선 근사 알고리즘을 제안한다. 이 알고리즘은 같은 모양의 개체에 대하여 그 객체의 무게 중심을 이용하여 항상 일정한 특정 시작점을 찾음으로써 동일한 우세 점들을 재귀적으로 빠른 수행 시간에 찾는다. 또한 이 알고리즘은 열린 곡선, 닫힌 곡선 및 다각형 등 어떤 모양의 평면 도형에도 모두 적용 가능하다. 제안 알고리즘의 평균 시간 복잡도는 O(nlogn)이다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.1
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• pp.71-81
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• 1994

A method is presented for the analysis of curved segmentally erected prestressed concrete box girder bridges including time-dependent effects due to load history, temperature history, creep, shrinkage, aging of concrete and relaxation of prestressing steel. The segments can be either precast or cast-in-place. Thin-walled beam theory and finite element method are combined to develop a curved nonprismatic thin-walled box beam element. The element consists of three nodes and each node has eight displacement degrees of freedom, including transverse distortion and longitudinal warping of the cross section.

• Journal of the Korean Magnetics Society
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• v.7 no.2
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• pp.97-102
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• 1997

Off-track capability is used to determine the track pitch of hard disk drive system, and the off-track capability as a function of track pitch is called 747 curve. In this paper, 747 curves were simulated with computer. Side reading and recording parameters were obtained by magnetic field analysis using 3-D finite element method. Head read signal and noise voltages for calculation of signal to noise ratio (SNR) were obtained using reciprocity theorem. According to the 747 curves thus obtained, the off-track capability was increased as erase band width increased and as effective signal to noise ration $(SNR_{eff}}$ decreased. A simulated 747 curve and a measured 747 curve (using spin stand) of a planar silicon head with track width of 4.1 um were very similar, which indicated that the simulation was carried out properly.

• The Journal of Information Technology
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• v.5 no.1
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• pp.99-111
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• 2002

Due to non-linear characteristics of color spaces, color corrections using linear conversions for real image near color reappearance causes color distortions. In order to overcome this problem, the Bezier Curve, constructed with a set of arbitrary plane in the linear theory, has been used. However, the Bezier Curve increases in proportion to the number of data points, resulting in higher computational complexities. This paper attempts to use a Triplicated Piecewise Bezier Cubic-Curve (TPBC-Curve) of which the degree is cubic on the whole interval while keeping the characteristics of Bezier Curves. By Comparing the TPBC-Curve with Bezier Curve of 20 degree, the paper not only reduces the distortion during color correction but also lessens the relative increase of workload that is caused by the color correction in a small zone.

• Journal of Digital Convergence
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• v.12 no.10
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• pp.283-289
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• 2014

Personal rapid transit(PRT) systems have been highlighted in future transportation developments as a result of their potential as sustainable and eco-friendly transport solutions that provide demand-responsive mobility services. One of the most important characteristics of the personal rapid transit system(PRT) is that it can be constructed and operated at a low cost. A fundamental study on the alignment of the PRT guideway considering running stability was conducted in the present study. In addition, a parameter analysis of the major alignment design variables such as curve radius, transition curve length and cant was performed by vehicle dynamic analysis and optimum guideway alignments were proposed. The analysis results suggested that the theoretical values were satisfied and also confirmed the possibility of reducing the standard.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2000.04a
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• pp.393-396
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• 2000

본 연구에서는 필렛엔드밀을 이용하여 복합곡면을 가공하기 위한 새로운 접근방법을 제안한다. 이 방법은 "곡선기반 접근방법"으로 기존의 "점기반 접근방법"에 비하여 몇 가지 특징들을 가지고 있다. 본 연구에서는 다면체로 표현된 곡면을 대상으로 하고 있는데, 볼록한 모서리와 꼭지점에서는 정확히 옵셋시키고 오목한 부위에서는 옵셋 곡면이 겹치는 것을 허용한다. 옵셋된 곡면을 절단 평면으로 자르고, 같은 평면상에 있는 교선 중에서 겹치는 부분의 윗 부분을 택하면 공구 간섭이 제거된 공구 경로를 얻게된다. 즉 계산이 복잡한 오목지역에서의 옵셋 시 발생되는 간섭을 2차원 평면상에서 제거함으로써 계산 과정을 단순화시키고 안정적으로 만든다. 본 연구에서 제안한 방법은 PC에서 VC++로 구현되었으며 몇 가지 적용 예를 보여 주고 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.973-974
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• 2012

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.189-195
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• 2002

The differential quadrature method (DQM) is applied to computation of the eigenvalues of out-of-plane bucking of curved beams. Critical moments including the effect of radial stresses are calculated for a single-span wide-flange beam subjected to equal and opposite in-plane bending moments with various end conditions, and opening angles. Results are compared with existing exact solutions where available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used. New results are given for two sets of boundary conditions not previously considered for this problem: clamped-clamped and clamped-simply supported ends.