• Journal of applied mathematics & informatics
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• v.2 no.2
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• pp.75-82
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• 1995

4대의 제어점에 의해 정의되는 3차 Bezier 곡선을 구간적 (piecewise) 2차 Bezier 곡선으로 근사 하는 기하적인 알고리듬을 제시한다. 또한 제시한알고리듬의 오차해석을 통하여 수정된 알 고리듬을 구성한다. 분확방법을 동시에 사용하여 주어진 허용오차 이내의 구간적 2차 근사 곡선을 구할수 있다. 제시한 알고리듬은 오차해석을 이용하여 필요한 분활의 수행회수를 미 리 결정할수있는장점을 가지고있다.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.131-142
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• 1999

The general behavior of the curved girder including the warping effects can be presented as the series of differential equations developed by Vlasov. Generally, bending moment is the most important factor for engineer to decide the section of the girder. In order to accommodate easiness of the structural analysis for the curved girder bridge, this paper suggest the ratios of bending moment of curved gilder to that of straight girder. These ratios are presented by an approximate formula setting central angle ${\theta}(L/R)$ as a variable. The approximate formula of the maximum bending moment ratios and influence lines of all stress resultants can be used to design the three-span curved girder bridges.

• Journal of the Korea Society of Computer and Information
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• v.10 no.1 s.33
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• pp.35-44
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• 2005

The degree reduction of B-splines is necessary in exchanging parametric curves and surfaces of the different geometric modeling systems because some systems limit the supported maximal degree. In this paper, We provide an our experimental results in approximate conversion for B-splines apply to degree reduction. We utilize the existing Bezier degree reduction methods, and analyze the methods. Also, knot removal algorithm is used to reduce data in the degree reduction Process.

• Journal of the Korea Society of Computer and Information
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• v.4 no.4
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• pp.25-33
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• 1999

Exchanging parametric curves and surfaces between different geometric modeling systems often require degree reductions to approximate the curves and surfaces to the degree of supporting systems within the given tolerance. This paper is a research for approximate conversion of a degree reduction methods for Bezier curves in the data exchange between the different systems. Our approximate conversion is implemented that shows the experimental results with the others to reduce the degree from the given degree n to n-1 for the Bezier curves about the different degree reductions.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.303-304
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• 2019

본 논문에서는 모듈러 멀티레벨 컨버터(Modular Multilevel Converter, MMC) 고압직류송전(High Voltage Direct Current, HVDC)의 전도 손실 계산을 위한 반도체 스위치 V-I 특성 곡선 근사 방법을 제안한다. 일반적으로 V-I 특성 곡선은 정격 전류 구간에 대해서만 선형화하여 사용하지만, MMC HVDC의 경우 암 전류의 직류 오프셋에 의해 V-I 특성 곡선의 비선형 구간에서 손실 계산에 오차가 크게 나타난다. 따라서 본 논문에서는 암 전류의 부호에 따라 별도의 V-I 특성 곡선 근사를 적용하여 MMC HVDC의 전도 손실 계산의 정확성을 향상하는 방안을 제안한다. 전도 손실 계산 결과는 PSCAD 시뮬레이션으로 취득한 손실 값과 비교하여 결과를 검증하였다.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.4
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• pp.118-125
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• 1998

This paper presents the hybrid curve approximation with geometric boundary conditions as position vector and tangent vector of start and end point using a B-spline approximation and a genetic algorithm First, H-spline approximation generates control points to fit B-spline curries through specified data points. Second, these control points are modified by genetic algorithm(with floating point representation) under geometric boundary conditions. This method would be able to execute the efficient design work without fairing.

• Journal of KIISE
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• v.44 no.11
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• pp.1194-1208
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• 2017

A traditional average smoothing method is designed for smoothing out noise, which, however, unintentionally results in smooth corner points on the curvature accompanied with a shrinkage of curves. In this paper, we propose a novel curve smoothing method via polygonal approximation of the input curve. The proposed method determines the smoothing weight for each point of the input curve based on the angle and approximation error between the approximated polygon and the input curve. The weight constrains a displacement of the point after smoothing not to significantly exceed the average noise error of the region. In the experiment, we observed that the resulting smoothed curve is close to the original curve since the point moves toward the average position of the noise after smoothing. As an application to digital cartography, for the same amount of smoothing, the proposed method yields a less area reduction even on small curve segments than the existing smoothing methods.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.47-53
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• 1990

Polygonal approximation of digital curves is useful for the image analysis or data compression. There are methods of polygonal approximation using cone intersection using cone intersection which have relatively smaller number of break points and are executed in sequential process. Here a method of polygonal approximation is proposed, which is modified from Sklansky and Gonzales' method, and improves the speed by using integer operations.

• Journal of Sensor Science and Technology
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• v.9 no.6
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• pp.440-447
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• 2000

This paper describes a practical system to classify material temperature responses by composition of curve fitting and neuro-fuzzy inference. There are problems with a classification system which utilizes temperature responses. It requires too much time to approach the steady state of temperature response and it has to be filtered to remove the noise which occurs in experiments. Thus, this paper proposes a practical method using curve fitting only for transient state to remove the above problems of time and noise. Using the neuro-fuzzy system, the thermal conductivity of the material can be inferred on various ambient temperatures. So the material can be classified via its inferred thermal conductivity. To realize the system, we designed a contact sensor which has a similar structure with human finger, implemented a hardware system, and developed a classification software of curve fitting and neuro-fuzzy algorithm.

• Journal of the Korea Computer Graphics Society
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• v.17 no.3
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• pp.33-42
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• 2011

We present a new technique for removing interior knots of parametric B-spline curves. An initial curve is constructed by continuous $L_{\infty}$ approximation proposed by Eck and Hadenfeld. We employ Hausdorff distance to measure the shape difference between the original curve and the initial one. The final curve is obtained by minimizing their Hausdorff distance. We demonstrate the effectiveness of our technique with experimental results on various types of planar and spatial curves.