• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.440-442
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• 2000

필기 한글 문자 인식을 위해서는 패턴을 구성하는 획 성분을 분석하는 작업이 필수적이다. 획 성분 추출을 위해 사용한 세선화 방법은 입력 영상을 왜곡하는 단점을 가지고 있다. 이를 극복하기 위하여 본 논문은 입력 영상을 왜곡하지 않고 의미 있는 부품 단위로 분할하는 방법을 제안한다. 의미 있는 부품이란 유사 볼록하게 분할된 영역을 의미한다. 분할 방법은 먼저 입력 영상에 볼록 헐 연산을 적용하여 오목 영역을 생성한다. 이 오목 영역에서 분할 기준(anchor point)점을 탐지하고 획의 반대편 외곽선 상에서 분할 끝(terminal point)점을 찾아 분할 경로를 구성하여 획을 분할한다. 모든 부품이 유사 볼록 조건을 만족할 때까지 위 과정을 반복 수행한다. 제안한 방법은 두 개의 파라미터만을 가지며 간단한 프로시져로 구성되어 있다. 또한 필기 한글 패턴뿐 아니라 여러 언어에 적용 가능하다는 장점을 갖는다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.7B
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• pp.1282-1291
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• 2000

기존의 LQ-서보형 PI 설계방법은 보드선도 상에서 저주파와 고주파 영역에서의 루프전단함수의 특이값 일치에 기이한 설계상의 문제를 가지고 있다. 이러한 점을 해결하기 위해 역 최적제어와 볼록형 최적화기법에 기초한 새로운 설계 방법을 제안하고자 한다.

• Journal of Korea Multimedia Society
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• v.6 no.7
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• pp.1302-1311
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• 2003

This paper presents a more stable method of multiresolution editing for a triangular mesh. The basic idea of our paper is to embed an editing area of a mesh onto a 2D region and to produce 3D surfaces which interpolate the editing-information. In this paper, we adopt the extended convex combination approach based on the shape-preserving parameterization for the embedding, which guarantees no self-intersection on the 2D embedded mesh. That is, the result of the embedding is stable. Moreover, we adopt the multi-level B-spline approach to generate the surface containing all of 3D editing-information, which can make us control the editing area in several levels. Hence, this method supports interactive editing and thus can produce intuitive editing results.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.901-903
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• 2005

본 논문에서는 평면 상에 두 볼록집합 P와 Q가 주어졌을 때, P를 강체운동 하에서 수평 이동 및 회전이동하여 Q와 겹치는 영역이 근사적으로 최대가 되는 알고리즘을 제시한다. 임의의 양의 상수 $\epsilon$이 주어졌을 때, 본 알고리즘은 가장 많이 겹치는 넓이의 $1-\epsilon$ 배를 보장하는 P의 강체운동을 $O((1/\epsilon)$ 번의 기하 질의 와 $O((1/{\epsilon}^2)log(1/$\epsilon)) 시간 내에 구할 수 있다. 특히 P와 Q가 볼록다각형 일 때, $O((1/\epsilon)log\;n+(1/{\epsilon}^2)log(1/\epsilon))$ 시간에 구한다. 만약 수평 이동만 사용할 경우는 $O((1/\epsilon)log\;n+(1/\epsilon)log(1/\epsilon))$ 시간에 구할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.6A
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• pp.855-861
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• 2000

This paper concerns a development of LQ-servo PI controller design on the basis of time-domain approach. The motivation is because the previous design techniques developed on the frequency-domain is not well suited meet the time-domain design specifications. Our development techniques used in this paper is base on the convex optimization methods including Lagrange multiplier, dual concept, semidefinite programming.

• Journal for History of Mathematics
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• v.29 no.6
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• pp.335-351
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• 2016

Spherical convexity may be defined in different ways. It depends on which statement we take as a definition among several statements that can be all used as a definition of convexity of subsets in an affine space. In this article, we consider this question from various perspectives. We compare several different definitions of spherical convexity which are found in mathematical papers. In particular, we focus our discussion on the definitions of J. P. $Benz{\acute{e}}cri$ and N. H. Kuiper who built a solid foundation for theory of convex bodies and convex affine(projective) structures on manifolds.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.6
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• pp.541-548
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• 2000

An area light source in the three dimensional space shines past a scene polygon, to generate two types of shadow volumes for each scene polygon, i.e., one with partial occlusion and the other with the complete occlusion. These are called, penumbra and umbra, respectively. In this paper, consider the problem for computing the umbra of a convex polygon from convex quadric light sources such as circles, ellipses, spheres, ellipsoids and cylinders. First, we give characteristics of the boundary surfaces of the umbra and then propose an algorithm for generating the umbra using them.

• ICROS
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• v.10 no.3
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• pp.27-33
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• 2004

최적화는 시스템공학에서 자주 등장하는 문제이며 흔히 다음과 같은 수학적 계획(mathematical programming) 문제로 표현된다. min f(x) (P) subject to g(x) ≤ 0 h(x) ： 0 여기서 x∈R/sup n/, f：R/sup n/→R, g：R/sup n/→R/sup l/, h：R/sup n/→R/sup m/, 그리고 n m이다. 만약 목적함수(objective function)와 가능 영역(feasible region)이 볼록(convex)하다면, 예를 틀어 f(x)와 g(x)가 아래로 볼록하고 h(x)가 선형이라면. 이는 볼록 문제(convex problem)이며 오직 하나의 지역 최소점(local minimum)을 가진다. 그러나 많은 경우. 예를 들어 h(x)가 비선형이라면, 여러 개의 지역 최소점을 가질 수 있는 비 볼록 문제(nonconvex problem)가 된다. 이때 진정한 최소점을 찾는 것. 즉 전역 최적화 (global optimization)가 요구된다.(중략)

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.2
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• pp.111-123
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• 2009

We present an efficient algorithm for computing the Hausdorff distance between two 2D convex polygons. Two convex polygons are bounded by k-DOPs and the regions of interest are traced using the orientational and hierarchical properties of k-DOP. The algorithm runs in a logarithmic time in the average case, and the worst case time complexity is linear.

• 대한공업교육학회지
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• v.43 no.1
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• pp.94-113
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• 2018

The purpose of this study is to develop a using various convex lenses 'VR glasses' instructional materials for area of communication technology of the 2015 Revision Curriculum in middle school. This study was progressed depend on ADDIE model. In the analysis step, a necessity of developing the instructional materials was confirmed through social needs and leaner's needs and literature researches were reviewed about the 2015 Revision Curriculum and virtual reality and confirmed the area of communication technology related to VR glasses. The communication process of information was selected as a communication technology area related to VR glass. In the design step, Based on the analysis stage, instructional objectives were set and instructional method and medium were selected. In the development step was developed instructional materials, what are teaching-learning guidance, power-point presentations, the paper for group learning activities, Individual portfolio, and using various convex lenses VR glasses example. As a result of 'VR glasses' using various convex lenses, the viewing angle was enlarged when the diameter of the convex lens was large, but it was difficult to quantify it. In the implementation step, the instructional materials developed for middle school students was applied. In the evaluation step, instructional materials were modified and improved through a students evaluation, experts evaluation.