• International Journal of CAD/CAM
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• 제5권1호
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• pp.11-18
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• 2005

The traditional method of manipulation of knots and degrees gives poor quality of surface, if compatibility of input curves is not good enough. In this work, a new algorithm of multiple refitting of curves has been developed using minimum energy based formulation to get compatible curves for skinning. The present technique first reduces the number of control points and gives smoother surface for given accuracy and the surface obtained is then skinned by compatible curves. This technique is very useful to reduce data size when a large number of data have to be handled. Energy based technique is suitable for approximating the missing data. The volumetric information can also be obtained from the surface data for analysis.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2003년도 춘계공동학술대회
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• pp.1122-1127
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• 2003

Typical application of detecting piecewise-linear curves includes vectorizing of scanned drawings whirh is a vital step in installing any geographic information system. This paper considers the problem of optimally approximating a piecewise linear curve to a set of digital points while satisfying given intersection angles between each pair of neighboring lines. The criterion for optimality is to minimize the sum of squared deviations. The problem is formulated as an unconstrained nonlinear programming model. An algorithm which guarantees an optimal solution is then proposed and its validity is tested with both a synthetically generated image and a real image. The test results illustrate the excellent performance of the proposed algorithm.

• 한국CDE학회논문집
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• 제3권2호
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• pp.140-144
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• 1998

We propose the area between a pair of non-self-intersecting 2-D parametric curves with same endpoints as an alternative distance metric between the curves. This metric is used when d curve is approximated with another in a simpler form to evaluate how good the approximation is. The traditional set-theoretic Hausdorff distance can he defined for any pair of curves but requires expensive calculations. Our proposed metric is not only intuitively appealing but also very easy to numerically compute. We present the numerical schemes and test it on some examples to show that our proposed metric converges in a few steps within a high accuracy.

• International Journal of CAD/CAM
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• 제12권1호
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• pp.29-37
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• 2012

A new algorithm has been developed to construct surface from the contours having branches and the final smooth surface is obtained by the reversible Catmull-Clark subdivision. In branching, a particular layer has more than one contour that correspond with at least one contour at the adjacent layer. In the next step, three-dimensional composite curve is constructed from contours of a layer having correspondence with at least one contour at the adjacent layer by inserting points between them and joining the contours. The points are inserted in such a way that the geometric center of the contours should merge at the center of the contours at the adjacent layer. This process is repeated for all layers having branching problems. Polyhedra are constructed in the next step with the help of composite curves and the contours at adjacent layer. The required smooth surface is obtained in the proposed work by providing the level of smoothness.

• 전자공학회논문지B
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• 제31B권8호
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• pp.119-128
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• 1994

In this paper we propose a new method for the recognition of 2-D partially occluded objects. The border of the object is transformed to a curve in arc length-accumulated interior angle plane. The transformed curve of an image is partitioned so that each segment is bounded by the concave interior angles. In order to tolerate shape distortion due to the polygonal approximation of the boundary of the object a group of feature points of the input image are matched with those of model views. The estimation method for positions and orientations of the identified objects objects is presented.

• 대한전기학회논문지
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• 제36권11호
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• pp.783-789
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• 1987

It is anticipated that the accuracy of the numerical value obtained by curve fitting is mainly governed by how to evaluate the term of exponential integral involved in the theory of TSC, so that evaluation process of the instegral term concerned is replaced by Romberg numerical integral method instead of the conventional approximation method of asymtotic expansion or Simmons-Tayler with expectation to get the improved accuracy. In order to examine the effectiveness of the proposed method, the new algorithm is tried to adapt to the peak of TSC observed about 356 K im the specimen of polyethylene terephthalate in which carrier is injected by means of corona dischargel. As theresults, it is confirmed that the proposed method being cooperated with Romberg numerical intergral intergral is superior to the existing conventional curve fitting method.

• 한국기계가공학회지
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• 제20권2호
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• pp.72-79
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• 2021

The present paper aims to set forth a two-dimensional theory for the dynamics of plates that is valid over a large range of excitation. To construct a dynamic plate theory within the long-wavelength approximation, two dimensional-reduction procedures must be used for analyzing the low- and high-frequency behaviors under the dynamic variational-asymptotic method. Moreover, a separate and logically independent step for the short-wavelength regime is introduced into the present approach to avoid violation of the positive definiteness of the derived energy functional and to facilitate qualitative description of the three-dimensional dispersion curve in the short-wavelength regime. Two examples are presented to demonstrate the capabilities and accuracy of all of the formulas derived herein by using various dispersion curves through comparison with the three-dimensional finite element method.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제24권1호
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• pp.177-193
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• 2010

본 연구는 고등학교 통계 영역의 확률분포에 제시되어 있는 정규분포를 이항분포에서 정규분포로의 근사, 정규분포곡선의 탐구, Monte Carlo 방법에 의한 정규분포곡선의 넓이 탐구, 정규분포곡선의 선형변환, 그리고 여러 형태의 정규분포곡선 탐구 등의 내용을 중심으로 CAS 계산기를 활용하여 탐구해보고자 한다. CAS 계산기의 도구적 기능인 사소화, 실험, 시각화, 집중의 측면에서 볼 때 지필로서는 교육과정에 제시된 확률분포의 목표를 달성하기 불가능하다고 판단된다. 따라서 본 연구에서는 CAS 계산기를 활용하여 정규분포곡선의 다양한 성질을 탐구하고 이러한 과정과 결과로부터 정규분포곡선에 대한 교수학적 시사점을 도출하고자 한다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2016년도 춘계 종합학술대회 논문집
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• pp.383-384
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• 2016

The Special Needs Education Assessment Tool (SNEAT) were verified of reliability and validity. However, the reliability and validity has been verified is only Okinawa Prefecture, the national data has not been analyzed. Therefore, this study aimed to verify the reliability and construct validity of SNEAT in Miyagi Prefecture as part of the national survey. SNEAT using 55 children collected from the classes on independent activities of daily living for children with disabilities in Miyagi Prefecture between November and December 2015. Survey data were collected in a longitudinal prospective cohort study. The reliability of SNEAT was verified via the internal consistency method; the coefficient of Cronbach's ${\alpha}$ were over 0.7. The validity of SNEAT was also verified via the latent growth curve model. SNEAT is valid based on its goodness-of-fit values obtained using the latent growth curve model, where the values of comparative fit index (0.997), tucker-lewis index (0.996) and root mean square error of approximation (0.025) were within the goodness-of-fit range. These results indicate that SNEAT has high reliability and construct validity.

• 한국산림과학회지
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• 제83권1호
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• pp.63-74
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• 1994

단목(單木) 또는 임분(林分)의 생장파악 및 예측을 위해서는 수간형태(樹幹形態)의 파악이 선행되어야 한다. 또한 임분의 생장을 동적(動的)으로 파악하기 위해서는 수간형태(樹幹形態)를 수식화(數式化)할 필요가 있다. 그러나 수간(樹幹)은 전체적으로는 원추형(圓錐型)에 가깝지만 그 가늘어지는 정도가 부분적으로 다르기 때문에 하나의 식(式)으로 표현하기엔 어려움이 있으므로, 부분적으로 상이한 계수를 갖는 구간추정식(區間推定式)으로 표현하는 것이 이상적이다. 본 논문에서는 spline함수로부터 유도된 단목간곡선의 집합으로부터, 선형관계식을 이용하여 임분간곡선(林分幹曲線)을 수식화하는 방법을 소개하였다. 이와 같이 수간형태(樹幹形態)를 수식화(數式化) 한 단목 및 임분의 간곡선식(幹曲線式)은 임분(林分)의 발달과정을 동적(動的)으로 파악할 수 있게 하여 임분생장연구의 다양성 및 합리적 산림계획모델의 기초를 제공한다.