• 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.

• 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 of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.85-89
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• 2012

Conventional grinding of BK7 glass will normally result in brittle fracture at the surface, generating severe sub-surface damage and poor surface finish. The precision grinding of BK7 glass in parallel grinding modes has been investigated. Grinding process, maximum chip thickness, ductile/brittle regime, surface roughness and sub-surface damage have been addressed. Special attention has been given to the condition for generating a ductile mode response on the ground surface. Experiments reveal that the level of surface roughness and depth of sub-surface damage vary differently for different condition. This study gives an indication of the strategy to follow to achieve high quality ground surfaces on brittle materials.

• The Journal of the Convergence on Culture Technology
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• v.6 no.1
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• pp.515-520
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• 2020

The design and actual implementation of the four-bar parallel link was studied in the paper. The parallel four-section link is widely used as a basic kinematic mechanism for transmitting the rotation of one axis to the rotational motion of the other axis. However, the parallel 4 link has a problem that phase reversal occurs at the turning point during the movement. In order to prevent the link reversal, it is known that a double parallelogram-type link is formed by attaching an additional phase reversal suppression link with an offset. However, as a result of the actual fabrication experiment, the movement is not smooth at the transition point. In order to solve this problem, in this study, a link for smooth movement is added in addition to a link that provides an offset to prevent phase reversal, so that the phase reversal does not occur at a specific point when the driven shaft rotates along the drive shaft. The test result confirms the validity of our suggestion.

• The Korean Journal of Applied Statistics
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• v.21 no.4
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• pp.695-704
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• 2008

The parallel coordinate plot is a graphical data analysis technique for plotting multivariate data. The parallel coordinate plot overcomes the visualization problem of the Cartesian coordinate system for dimensions greater than 4. But, using different ordering of coordinate axes in the parallel coordinate plot of the same data may make different interpretations. Hence, we can use the regular polyprism parallel coordinate plot as an alternative for overcoming the variable arrangement problem of the parallel coordinate plot.

• 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 Society of Manufacturing Process Engineers
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• v.13 no.2
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• pp.100-107
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• 2014

Currently, there are many power transmission devices, including gears, friction wheels, chains, and belts. Because the power transmission of gears is most certainin these devices, gears are widely used in different power transmission fields and environments. In accordance with the gear shape, gears can be classified as cylindrical gears and conical gears. A cylindrical gear, which provides a means of power transmission under parallel axis and skewed axis conditions, contains a spur gear, a helical gear and a worm gear. A conical gear, which can be used on a skewed axis as well as parallel and crossed axes, includes a bevel gear(e.g., straight bevel, spiral bevel, hypoid gear) and a conical involute gear(or a bevel oid gear). In this paper, a conical involute gear which utilizes the fabrication method of other involute gears such as spur and helical gears using a CNC hobbing machine is discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.627-629
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• 2017

There are a lot of research results on the problem of finding the union and intersection of n rectangles on a plane. Lipski와 Preparata(1981) presented a sequential algorithm with O(nlogn) time and O(nlogn) space for the problem of finding the union of rectangles whose sides are parallel to the coordinate axes[1]. Alevizos(2013) presented an improved O(nlogn) time and O(n) space algorithm for the same problem[2]. In this paper, we consider the problem of finding the union of iso-oriented rectangles such that the intersection of them is not an empty set. In this case, the union of the rectangles becomes a connected area, that is, an orthogonal polygon. In this paper, we propose a parallel algorithm that solves this problem in constant time in a reconfigurable mesh(in short, RMESH) model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.311-318
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• 2005

Periodically perforated slot structure in the upper wall of the parallel plate waveguide is analyzed with main interest focusing on the diffraction Properties. The Periodic slot array is of infinite extent in one direction and of finite extent in the other direction. Various numerical results for reflection from the slotted section and transmission beyond the slotted section, and the radiation through the slotted section into the upper half space are presented with the height of feeding parallel plate waveguide, single slot size, and the periodicity between slots as parameters. This study is thought to be helpful to the design of the ventilation hole in the TFT-LCD and PDP.

• School Mathematics
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• v.17 no.3
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• pp.407-421
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• 2015

Linear system is a basic subject matter of school mathematics courses. Even though elimination is a useful method to solve linear systems, its fundamental principles were not discussed pedagogically. The purpose of this study is to help the development of mathematical content knowledge on linear systems conceptions. To do this, various representations and translations among them were considered, and in particular, the basic principles for elimination method are analyzed geometrically. Rectangular representation is used to solve word problem treated in numbers of things in elementary mathematics and it is useful as a pre-stage to introduce elimination. Slopes and intercepts of lines associated linear equations are used to obtain the Cramer's formula and this solving method was showing the connection between algebraic and geometric procedures. Strategy deleting variables of linear systems by elementary operations is explored and associated with the movements of lines in the family of lines passing through a fixed point. The development of mathematical content knowledge is expected to enhance pedagogical content knowledges.