• 호남수학학술지
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• 제39권1호
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• pp.127-136
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• 2017

For a quadrangle P, we consider the centroid $G_0$ of the vertices of P, the perimeter centroid $G_1$ of the edges of P and the centroid $G_2$ of the interior of P, respectively. If $G_0$ is equal to $G_1$ or $G_2$, then the quadrangle P is a parallelogram. We denote by M the intersection point of two diagonals of P. In this note, first of all, we show that if M is equal to $G_0$ or $G_2$, then the quadrangle P is a parallelogram. Next, we investigate various quadrangles whose perimeter centroid coincides with the intersection point M of diagonals. As a result, for an example, we show that among circumscribed quadrangles rhombi are the only ones whose perimeter centroid coincides with the intersection point M of diagonals.

• 만화애니메이션 연구
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• 통권23호
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• pp.51-66
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• 2011

로돌페 퇴퍼(Rodolphe Toeppfer)가 그림과 글이 결합된 형식을 정의하면서 만화 칸을 이용한 이후로 여러 만화작가들에 의해 만화 칸은 현재와 같은 모습으로 정착했다. 그러나 만화 칸이 본격적으로 정의되기 이전에도 만화 칸의 형식을 엿볼 수 있는 역사적 기록들이 있었다. 역사적인 기록 속에서 칸은 무형 또는 유형의 사각형으로 발견되어왔다. 우리가 지금 보는 만화 칸은 어딘가에서 생겨난 것이 아니라 이전부터 이어진 역사적인 산물이다. 창작자는 이렇게 칸이라고 부르는 틀 안에, 만화의 어휘에 속하는 그림이나 글을 넣는다. 만화 칸은 카메라의 프레임과 비슷하지만 이들과는 달리 가로 세로 비례의 틀이 유동적이다. 창작자들은 다양하게 칸을 이용했고 이러한 과정을 거치며 칸을 정형화시켰다. 결과적으로 만화 칸은 대부분 사각형으로 정립됐다. 만화 칸이 사각형으로 굳어져 간 과정에는 인간의 생활양식에 따른 암묵적인 규칙이 작용했을 것이라고 생각한다. 인간 문명을 이루는 수많은 도형 중에서 만화 칸이 사각형으로 이뤄지게 된 원인이 무엇일까? 본 논문은 이 같은 물음을 근거로 사각형의 형태를 기준으로 이뤄지는 인간의 생활체계를 알아보고 어떤 장점이 만화 칸을 사각형으로 정립되게 만들었는지 연구해 볼 것이다.

• 한국수학교육학회지시리즈A:수학교육
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• 제61권2호
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• pp.323-338
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• 2022

이 연구의 목적은 중학생과 고등학생의 사각형에 대한 개념 정의 이해 정도를 분석하고 개념 이미지에 대한 현상을 탐색하는 것이다. 이를 위해 검사 도구를 개발하고 중학교 2학년 60명, 중학교 3학년 63명, 고등학교 1학년 65명을 대상으로 검사하고, 일부의 학생을 면담하였다. 연구 결과는 다음과 같다. 첫째, 학년이 올라감에 따라 자연적으로 사각형의 개념 정의에 대한 이해도가 향상된다고 볼 수 없다. 특히, 모든 학년에서 다른 사각형과 비교하여 마름모 개념 정의에 대한 이해도가 가장 낮은 것으로 나타났다. 둘째, 정사각형에 대한 개념 정의는 여학생이 남학생보다 더 잘 이해하지만, 사다리꼴, 평행사변형, 마름모, 직사각형에 대한 개념 정의에 대한 이해 정도는 성별로 차이가 없는 것으로 나타났다. 셋째, 사각형 개념 정의를 이해하지 못하는 학생은 학년이 올라갈수록 개념 이미지의 영향을 점점 더 크게 받는 것으로 나타났다. 넷째, 학년이 올라갈수록 학생의 사각형에 대한 개념 이미지 형성에 개념 정의의 영향은 줄어들고 교과서나 교사의 영향이 증가하는 경향을 보여주었다.

• 건축사
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• 11호통권463호
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• pp.40-45
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• 2007

• 동의생리병리학회지
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• 제21권2호
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• pp.379-386
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• 2007

Hado(河圖) and Laks${\u{\lrcorner}}$(書洛) are the diagrams composed of the symbols of numbers from one to ten. And the eight-trigrams, P'al-gwoe divide into two types one is a priori eight-trigrams (先夭八卦) or the Bok-Hui's eight trigrams(伏羲八卦); and the other is a posterior eight trigrams (後夭八卦) or the king Mun's eight trigrams (文王八卦). Relating these two diagrams of Hado and Laks${\u{\lrcorner}}$ with the two types of eight trigrams, they are said to be a term of Ha-Lak-Hui-Mun (HLHM). Each of HLHM represents the process of creating and changing of 'heaven and Earth' and every beingby the symbols of numbers and trigrams. In other words, each of HLHM symbolizes the origin and the structure of the universe as well as the birth of every life represented in the diagram of theosophany (福智學) or Kabbalah. HLHM are also regarded as the origin of l-ching or Book of Change. Hado produces Laks${\u{\lrcorner}}$ through the principle of yin-yang(陰陽). Laks${\u{\lrcorner}}$ produces a priori eight trigrams through the zigzag shapes which means Heaven and Earth are mutually responding. And a priori eight trigrams produce a posteriori eight trigrams through the triangle principle of connecting Heaven and Earth. In this process, Hado and a priori eight trigrams are respectively prior to Laks${\u{\lrcorner}}$ and a posteriori eight trigrams. HLHM represent fractal shape resembling the symbol of five on the center of Hado, or Hado itself. In the dynamic process of HLHM, a diagram of Circle, Quadrangle, and Triangle (CQT) is produced as follows: Circle, the symbol of 'infinify' or Heaven, represents the origin of life or birth. Hadois the symbol of creation. Quadrangle, the symbol of Earth, represents that Laks${\u{\lrcorner}}$is scattered into four directions of front, back, left, and rifht. Quadrangle, which is immovable, represents materiality. Triangle, being described from the eight trigrams, means the movements of the process of 'mutual inclusion' of Circle and Quadrangle. Triangle also means the process of harmonizing human beings with natural law.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.721-724
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• 2000

This paper presents fingerprint authentication method based on minutiae quadrangle definded by neighboring two Delaunay triangles. In this method, we first make minutiae triangle through Delaunay triangulation which adaptively connect neighboring minutiae according to the local minutiae density distribution, and then use feature vectors in authentication which is extracted from the minutiae quadrangle formed by neighboring two minutiae triangles. This prevents the degradation of matching ratio caused by the errors in image processing or local deformation of the fingerprint, and we can authenticate more discriminately as this method reflects wider local area's topological features than the features extracted from the individual minutiae triangles. To evaluate the proposed algorithm's performance, experiment are conducted on 120 fingerprints, of which size is 256 ${\times}$ 364 with 500dpi resolution. Robust authentications are possible with low FRR.

• 설비공학논문집
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• 제14권12호
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• pp.1014-1022
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• 2002

This paper analyzed the characteristics of heat transfer in quadangle duct with absorber plate by solar radiation. Effects o( Reynolds number on increasing temperature at outlet for variation of absorber plate temperature were analyzed by using numerical analysis technique. And also the effects of turbulent intensity of inlet flow on increasing temperature at outlet for various duct height and effects of inlet aspect ratio of quadrangle duct and position of heating surface on the outlet temperature were analysed. As the results, Outlet temperature was greatly influenced in low Reynolds number. And the highest outlet temperature distribution appeared on the inlet aspect ratio 2 because of the buoyancy effect.

• 한국정밀공학회지
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• 제17권6호
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• pp.143-152
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• 2000

The comer filling in shaped drawing process is an important characteristic, unlike the round drawing. It has also influence on the dimensional accuracy of the product. In this study, therefore, the shaped drawing process has been simulated by the three dimensional rigid-plastic finite element method in order to investigate the effect of process variables such as reduction in area and semi-die angle to the corner filling. The artificial neural network has also been introduced to reduce the number of simulations. To verify the results of simulations, experiments have been performed on the real industrial products. According to the results, the main process variable on the corner filling is the combination of semi-die angle in the irregular shaped drawing processes, but in the case of regular shaped drawing processes, reduction in area has great influence on the corner filling.

• 대한수학회논문집
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• 제32권1호
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• pp.135-145
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• 2017

For a polygon P, we consider the centroid $G_0$ of the vertices of P, the centroid $G_1$ of the edges of P and the centroid $G_2$ of the interior of P. When P is a triangle, (1) we always have $G_0=G_2$ and (2) P satisfies $G_1=G_2$ if and only if it is equilateral. For a quadrangle P, one of $G_0=G_2$ and $G_0=G_1$ implies that P is a parallelogram. In this paper, we investigate the relationships between centroids of quadrangles. As a result, we establish some characterizations for rhombi and show that among convex quadrangles whose two diagonals are perpendicular to each other, rhombi and kites are the only ones satisfying $G_1=G_2$. Furthermore, we completely classify such quadrangles.

• 한국실내디자인학회논문집
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• 제38호
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• pp.14-20
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• 2003

In 1923, El. Lissitzky designed ‘Proun Raum’ to realize his spatial experiment in paintings that are called 'Proun'. For this, Lissitzky taken Pome 'element' to construct his imaginary space that combine time with space. Especially, Quadrangle make an important role by the reason of its potential energy. In other words, alteration of its four corners turn Quadrangle to rectangle or square, etc, and describe some force, motion and location as itself. Analyzing 'Proun' and 'A and Pangeometry' that describes his spatial concept, spatial characteristics of 'Proun Raum' are comprehended, and the significance of spatial construction method in 'Proun Raum' are summarized as follows; occurrence of spectator's visual guide by elements, secession of afterimage, do-construction of the border.