• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.463-466
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• 2017

The purpose of this paper is to develop a module capable of all-directional driving different from conventional wheeled robots, and to solve the problems of the conventional mobile robot with side driving performance degradation, It is possible to overcome the disadvantages such as an increase in the time required for the unnecessary driving. The all - direction spherical wheel drive module for driving a ball - balancing robot is required to develop a power transfer mechanism and a driving algorithm for driving the robot in all directions using three rotor casters. 3DoF (Axis) A driver with built-in forward motion algorithm is embedded in the module and a driving motor module with 3DoF (axis) for driving direction and speed is installed. The movement mechanism depends on the sum of the rotation vectors of the respective driving wheels. It is possible to create various movement directions depending on the rotation and the vector sum of two or three drive wheels. It is possible to move in different directions according to the rotation vector field of each driving wheel. When a more innovative all-round spherical wheel drive module for forward movement is developed, it can be used in the driving part of the mobile robot to improve the performance of the robot more technically, and through the forward-direction robot platform with the drive module Conventional wheeled robots can overcome the disadvantage that the continuous straightening performance is lowered due to resistance to various environments. Therefore, it is necessary to use a full-direction driving function as well as a cleaning robot and a mobile robot applicable in the Americas and Europe It will be an essential technology for guide robots, boarding robots, mobile means, etc., and will contribute to the expansion of the intelligent service robot market and future automobile market.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.39-49
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• 1986

The purpose of this study was to observe characteristic properties through the polarization curves and SEM images from 4 different types of amalgam obtained by using the potentiostats (Princeton EG & G) & SEM (Jeol/35), and to investigate the degree of corrosion on the oxidation peak of the each phase of amalgam. After each amalgam alloy and Hg was triturated as the direction of the manufacturer by means of the mechanical amalgamator (Shofu Co.), the triturated mass was inserted into the cylindrical metal mold which was 12mm in diameter and 10.0mm in height and was condensed by using routine manner. The specimen was removed from the mold and stored at room temperature for about 24 hours. The standard surface preparation was routinely carried out. Anodic polarization measurement was employed to confirm the corrosion behaviour of the amalgams in a 0.9% saline solution (P.H: 6.8-7.0) at $37^{\circ}C$. The initial rest potential (corrosion potential) was determined after 30 minutes of immersion of specimen in electrolyte, and the potential scan was begun at the point of 100mV cathodic from the corrosion potential. The scan rate was 0.17mV/sec. in the study to observe the degree of corrosion of each phase. SEI and EPMA images on the determined oxidation peaks of each amalgam were observed. The results were as follows: 1. In the four anodic polarization curves, low copper amalgams have three oxidation peaks and high copper amalgams have two oxidation peaks, -270mV, +26mV and +179mV(SEC) in the low copper lathe cut, and -300mV, +39mV and +163mV(SEC) in the low copper spherical. -4mV and +154mV(SEC) in the Dispersalloy, and +17mV and +180mV(SEC) in the Tytin as high copper amalgams. 2. ${\gamma}_2$ phase in the low copper amalgam and ${\eta}$ phase in the high copper amalgam were the most corrodible phases and Ag-Cu eutectic in high copper amalgam was the most slowly corroded phase. 3. Low copper amalgam was more susceptible in corrosion than high copper amalgam.

• Korean Journal of Optics and Photonics
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• v.16 no.5
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• pp.440-445
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• 2005

The limitation of measurement accuracy and reliability of autostigmatic null lens system are studied for the cases of using inter-distance of null lenses as the adjustment factor of alignment and fixing the distance by mounting. If we investigate the first case, the wavefront aberration of null lens system is compensated by the adjustment process even though the shape of aspherical surface is not properly fabricated. As the result, it brings about the problem of measurement reliability. However, for the fixing process by mounting null lenses, it doesn't cause the reliability problem because the wavefront aberration of null lens system is not compensated. Further, the fixing process shows nearly same result in measurement accuracy to the adjustment process, that is, $0.0316{\lambda}$ vs. $0.0326{\lambda}$. So, we can conclude the setup for autostigmatic null lens system must be constituted by means of the fixing process. Meanwhile, we introduce and define the alignment aperture on aspheircal mirror, which can be approximated as spherical zone for alignment of null lens system, and besides, we calculate the required fabrication accuracy of the zone for the necessary measurement accuracy.

• Journal of the Korean Society of Costume
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• v.13
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• pp.21-37
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• 1989

In May 1987, 11 clay icons and other stone products were excavated in an abandoned ancient tomb which was located in 541-1 Hwangsung-dong, Kyungju. 6 clay figures of them were depicted realistically man's features and postures, costume at that time that they gave a lot of significance to the fields of Korean Costume's Academic Society. The main purpose of this thesis is to study the background of costume history when it was made and its formal characteristics with the study of those 6 clay figures. Shilla accepted the customs and attires of Sui and T'ang by means of frequent in coming and out going Chinese envoy as well as Shilla's envoy, monks, hostages, and students in China. From that period, the diversity of Shilla's costume began to develop by introducing Tang's style into Shilla's costume. Crested hat of men's clothing of the clay figures in Hwangsung- Dong is Bokdu Men's figure II wore Bokdu which Hugak is attached to Byunhyung. The garment is a Po and it is a tight sleeve and silhouette's Banryungpo. The horizontal line of hemline of men's figure 1 can be presumed by expression of Ran though it is not as accurate as the clay figues in Yongg-ang-Dong. As for torso part 1, it can not be known the style of the crested hat because the head part was damaged, but it were shoes, belt and common sleeve, Banryungpo on tight sleeve shirt and tight trouser. The hair style of the women's clothing in Hwangsung-dong clay figure is Bukkye peculiar to Korea. The costume was slim silhouette that people wore tight sleeve and short blouse and long skirt and belted on their bosom which dresses style was in vogue from late Sui dynasty to the early years of the Tang period. The silh ouette of slim silhouette's high waist which can be seen in the women's dresses is mainly worn by Chinese and affected Shilla's costume. Therefore the dresses style of the clay figures in Hwagsung-Dong, it is considered it is a dresses style of tight sleeves and slim silhouette together with the adaptation and abolition of foreign elements on the basis of Shilla's own elements like Bukkye hair style and tight sleeve and silhouette. The style of Yonggang-Dong's clay figures expresses spherical gei and common sleeve, loose silhouette of flourishing Tang's costumes planly whereas the style of Hwangsung-Dong's clay costumes expresses refined spirit of the Shilla(Shillaism) though it is extremly simple.