• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2002.11a
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• pp.297-301
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• 2002

본 논문에서는 신호처리를 이용한 평행축 입체 카메라의 주시각 제어 방법을 제시한다. 평행축 입체 카메라는 양안식 입체 카메라 중 가장 간단하게 만들 수 있는 장점이 있는 반면에, 좌, 우 영상센서 사이의 거리가 일정하게 고정되어 있어, 물체의 거리 변화에 따른 입체 영상 시차 조절 기능인 주시각 제어 기능이 없다는 단점이 있다. 영상 센서 (CCD) 와 렌즈를 분리하고 영상 센서가 평행하게 수평으로 움직이며 주시각을 제어하도록 하는 수평 이동축 입체 카메라는 평행축 입체 카메라의 단점을 보완할 수 있지만, 실제 구현에 많은 어려움이 있다. 본 논문에서는 주시각 제어를 위한 CCD의 이동은 실제 영상에서 피사체의 이동으로 나타난다는 사실을 이용하여, 평행축 입체 카메라로 얻은 영상에서, CCD의 이동으로 인해 사라지는 부분만큼 제거하고 영상의 수평 수직 방향에서 원래 영상의 크기로 복원하기 위해 보간하는 과정을 통해 주시각 제어를 구현한다. 제안된 방법을 통해 얻어진 실험 결과는 CCD의 이동량에 따라서 화질의 열화 정도가 다르게 나타남을 보여 주지만, 실제 시스템에서 CCD의 이동량은 크지 알기 때문에 화질 열화를 거의 느끼지 않으면서 주시각이 제어된 입체 영상을 얻을 수 있음을 보여준다.

• School Mathematics
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• v.14 no.3
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• pp.297-313
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• 2012

The purpose of this paper is to discuss the potential and to examine the effect of narrative, as an alternative approach to teach formal proof in more easier and comprehensible way. Identifying the key elements of narrative in proof, we constructed a narrative that derives the equation of function translation. We examined the effect of teaching through the narrative, in comparison with teaching the corresponding proof, on low-achieving students' instrumental understanding and relational understanding of function translation. Since we found no statistically significant differences between the experimental and the comparison group, this study could not conclude that teaching through the narrative was more effective than teaching the corresponding proof. But there were some qualitative differences in the relational understanding responses and the evaluation of the teaching between two groups. These findings suggested some potential of narratives that complement the formal proof.

• Journal of the Korea Computer Graphics Society
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• v.6 no.4
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• pp.29-34
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• 2000

This paper classifies the structure of the intersection curve between a surface of extrusion and a free-form surface. Our algorithm computes the silhouette curve of the free-form surface with respect to the unique ruling direction of the surface of extrusion. By intersecting the silhouette curve and the base curve of the surface of extrusion, we can classify the topological structure of the intersection curve, and compute all singularities in the intersection curve. Moreover, we can determine which ruling lines of the surface of extrusion intersect the other free-form surface and how many times. This classification provides a robust and efficient method for computing the intersection curve.

• Communications of Mathematical Education
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• v.33 no.2
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• pp.105-122
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• 2019

In Korean textbooks, by T(x,y) = (x+a, y+b) where a and b are horizontal and vertical changes respectively, an arbitrary point on the original figure f(x, y) = 0 has been expressed as a point (x, y) and a point on a translated figure f(x-a, y-b) = 0 has been expressed as a point (x', y'). If an arbitrary point on a figure f(x, y) = 0 is expressed as a point (x, y), then a point (x, y) and a figure f(x, y) = 0 are different targets but the same characters are used. In this following study, there were found that the expressions in these textbooks were stuck for more than 50 years, so students' thoughts were stiff. And therefore these are a need to be improved so that those things are studied as follows. First, inducing a formula, what are the students' responses like when were expressed differently from textbooks? Second, based on the results reviewed, how will the expressions of the textbook be revised? Third, how do the students respond to the modified expressions? As the result, a point on the original figure were expressed differently from textbooks and a point on a translated figure was put as a point (x, y), and about it, all of the students surveyed said that this improved expressions made in the study were easier.

• Journal of Korea Multimedia Society
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• v.16 no.2
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• pp.160-168
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• 2013

In this paper an algorithm that represents shape sequences with moving frames parallel along the sequences are developed. According to Levi-Civita connection, it is not easy to measure the variation of the vector fields on non-Euclidean spaces without tools to parallel transport them. Thus, parallel transport of the vector fields along the shape sequences is implemented using the theories of principal frame bundle and analyzed via extensive simulation.

• Communications of the Korean Mathematical Society
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• v.15 no.1
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• pp.111-121
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• 2000

유클리드 공간의 정의와 평행이동 및 벡터의 성질을 현대적인 관점에서 살펴본다. 또 이를 이용하여 아핀 공간을 정의한다.

• The KIPS Transactions:PartB
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• v.10B no.2
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• pp.151-156
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• 2003

The vergence control method is presented for a parallel-axls stereo camera (PASC) using a signal processing technique such as shift, (rotation), and scaling. The PASC is considered as the simplest one of binocular stereo cameras. However, its major limitation lies in the controllability of vergence since its left and right imaging sensors of CCDs are fixed. On the other hand, a horizontal-moving-axis stereo camera (HMASC) with movable imaging sensors is able to control the vergence by moving its CCDs horizontally. In spite of its vergence controllability, there is a major drawback in the implementation because of complicated mechanical structure and the additional cost. To overcome the vergence control problem of the PASC, an operational principle of the HMASC is applied to the PASC. To be specific, without any additional hardware the vergence control problem of the PASC is solved with the signal processing technique. Assuming the virtual displacement between CCD's, a disappearing part of acquired images is removed and the original image site is recovered via interpolation. Experimental results show that the vergence control between stereo images captured by the PASC it possible with an acceptable degradation of the image quality defending on the virtual displacement of CCDs.

• Journal for History of Mathematics
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• v.21 no.2
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• pp.71-80
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• 2008

From the ancient Korea, our ancestor had designed the unique pattern which is Dan-chung, in architectures such as palace and Buddhist temple. In Dan-chung pattern, there are many various kinds, that is geometric pattern, arabesque pattern, plant pattern, flower pattern, animal pattern, Buddhist pattern and living pattern. So, we can see the tessellations in the Dan-chung pattern, moreover we can find the beauty of tessellation in the Korean traditional architectures and crafts. In this paper, I'll show you Korean traditional tessellations via GSP 4.0. which means geomeric program Geometer's SkechPad.

• Journal for History of Mathematics
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• v.27 no.6
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• pp.387-394
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• 2014

Since ancient civilization, solving equations has become one of the most important subjects in mathematics and mathematics education. The extractions of square roots and cube roots were first dealt in Jiuzhang Suanshu in the setting of subdivisions. Extending these, Shisuo Kaifangfa and Zengcheng Kaifangfa were introduced in the 11th century and the subsequent development became one of the most important contributions to mathematics in the East Asian mathematics. The translation of coordinate axes plays an important role in school mathematics. Connecting the translation and Kaifangfa, we find strong didactical implications for improving students' understanding the history of Kaifangfa together with the translation itself although the latter is irrelevant to the former's historical development.

• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.191-199
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• 2003

It is known that the distribution of the active earth pressure against a rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the farmer paper, a new formulation was proposed for the nonlinear distribution of active earth pressure on a translating rigid retaining wall considering arching effects. In this paper, parametric study is performed to investigate the effect of ${\phi}, {\delta}$ and wall height on the magnitude and distribution of active earth pressure calculated from the proposed equations. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the lateral active earth force on the translating wall. Simplified design charts are also proposed for the modified active earth pressure coefficient and fur the height of application of the lateral active force in order to facilitate the use of the proposed equation.