• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.115-121
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• 2007

This paper describes experiments of the breakdown characteristics by temperature change of $SF_6$ gas and Imitation Air(I-Air) in model GIS(Gas Insulated Switchgear). From the results of the experiments, the breakdown characteristics classify the vapor stage of $SF_6$ according to Paschen's law, in which the stage of coexistence for gas & liquid of the voltage value increases. This results in large deviation and the breakdown of the voltage(VB) low stage as the interior of the chamber is filled with a mixture of $SF_6$ that is not liquefacted and remaining air that can not be ventilated. The ability of $SF_6$ liquid($LSF_6$) insulation is higher than high-pressurize $SF_6$ gas. The VB of the I-Air decreases as the temperature drops and the VB also drops. It is considered that the results of this paper are fundamental data for the electric insulation design of superconductor and cryogenic equipment that will be studied and developed in the future.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1671-1673
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• 2003

Faraday효과를 기본으로 하는 광CT(Optical Current Transformer)는 기존의 CT의 결점을 개선하여 경제적 효과의 증대, 신호제어 시스템의 신속성향상, Digital 계전시스템의 호환성에 크게 기여한다는 점 등 많은 면에서 장점을 가지고 있다. 본 연구에서는 광섬유센서 기술을 응용하고, Faraday 효과의 편광면 회전량을 수광부에서 김출하여 대전류 측정을 위한 광 CT의 동작특성에 대한 실험을 하고자 한다. 실험에 사용찬 광원은 633[nm] He-Ne Laser와 1310[nm] Laser Diode 두 가지로 동일한 시스템으로 구성하여 비교한다. 센싱부의 광섬유는 길이 10[m]의 633[nm] 1310[nm]용 single-mode bare fiber를 전류가 흐르는 케이블에 감아 센싱부를 구성하고, 전류변화에 따른 두 출력값을 측정, 비교하고자 한다.

• Journal of the Korean institute of surface engineering
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• v.36 no.4
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• pp.296-300
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• 2003

Extended cylindrical magnetron sputtering system with rotating 600-mm long and 90-mm diameter graphite cathode and pulsed power supply voltage generator were developed and fabricated. Time-dependent Langmuir probe characteristics as well as carbon films thickness were measured. It was shown that ratio of ions flux to carbon atoms flux for pulsed magnetron discharge mode was equal to $\Phi_{i}$ $\Phi$sub C/ = 0.2. It did not depend on the discharge current in the range of $I_{d}$ / = 10∼60 A since both the plasma density and the film deposition rate were found approximately proportional to the discharge current. In spite of this fact carbon film structure was found to be strongly dependent on the discharge current. Grain size increased from 100 nm at $I_{d}$ = 10∼20 A to 500 nm at $I_{d}$ = 40∼60 A. To deposit fine-grained hard nanocrystalline or amorphous carbon coating current regime with $I_{d}$ = 20 A was chosen. Pulsed negative bias voltage ($\tau$= 40 ${\mu}\textrm{s}$, $U_{b}$ = 0∼10 ㎸) synchronized with magnetron discharge pulses was applied to a substrate and voltage of $U_{b}$ = 3.4 ㎸ was shown to be optimum for a hard carbon film deposition. Lower voltages were not sufficient for amorphization of a growing graphite film, while higher voltages led to excessive ion bombardment and effects of recrystalization and graphitization.

• Journal of Environmental Science International
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• v.31 no.4
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• pp.369-372
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• 2022

This study was conducted to determine the injury type and frequency of bearded dragons during single and group breeding according to stocking density, for 16 weeks. A total of 14 bearded dragons compromising three groups were selected for this study. Six and four bearded dragons bred in a cage of 45 cm × 45 cm × 45 cm were designed as group A and B, respectively. Group C was made of four partitions (20 cm × 20 cm × 20 cm) of equal size in the kennel, and the dragons, four in number, were reared alone. Injury type criteria were given 1 score each in 6 stages. Most of the injury types in group A were primary tail cutting, which was 1 point, depending on the score, except for 4 scores. The injury type of group A varied, that is 1, 2, 3, and 5 scores, and the pattern lasted for 2 to 9 weeks. After 10 weeks, the dragons showed no response to injury type, except 4 scores at 11 weeks and 2 scores at 14 weeks with a frequency of one, respectively. The representative injury types of the group B were primary tail cutting, which was 1 point, and the scores of the injury type from 2 to 11 weeks were the highest; the frequency of occurrence at 1 and 2 scores was 5 times and 3 times, respectively, and the frequency of occurrence at 3 scores was twice. In addition, 5 scores were found to have the lowest frequency of occurrence. Solitary breeding showed no response to the type of injury for 16 weeks. Consequently, single breeding with an appropriate stocking density did not affect stress, and it could be expected a positive aspect for pet welfare.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.139-145
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• 1999

The objective of this study is to provide the information on the small-scale model mix proportion when the behavior of prototype concrete pavement is studied through small-scale model experiments. However it is difficult to obtain a model material to simulate the prototype concrete by scaling the individual components according to the laws of similitude. In this paper, the stress-strain behavior in uniaxial compression is used as a means to correlate material similitude between the prototype and the model concrete. Based on the results of experiments, we compared the stress-strain curves of prototype and model concrete mixes using a nondimensional basis. In order to simulate the stress-stain curves of prototype concrete, it is important that various mix proportions of model concrete selected properly which are varied from aggregate grading, cement-aggregate and sand-aggregate ratio.

• Journal of KIISE:Software and Applications
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• v.36 no.7
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• pp.523-530
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• 2009

Despite the growing need for customized operating system kernels for embedded devices, kernel development continues to suffer from insufficient reliability and high testing cost for several reasons such as the high complexity of the kernel code. To alleviate these difficulties, this study proposes the MOdel-based KERnel Testing (MOKERT) framework for detection of concurrency bugs in the kernel. MOKERT translates a given C program into a corresponding Promela model, and then tries to find a counter example with regard to a given requirement property, If found, MOKERT executes that counter example on the real kernel code to check whether the counter example is a false alarm or not, The MOKERT framework was applied to the Linux proc file system and confirmed that the bug reported in a ChangeLog actually caused a data race problem, In addition, a new data race bug in the Linux proc file system was found, which causes kernel panic.

• Journal of Korean Elementary Science Education
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• v.36 no.3
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• pp.273-285
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• 2017

The purpose of this study is to develop a program that enables students to participate in various experiential learning places in order to provide various experiences to students for solve the problem of prejudice to specific places such as science museum, zoo and botanical garden. For this purpose, the surveys were conducted about experiential places and awareness of experiential learning. 88 elementary school teachers participated in the survey. As a result, they were positive about the use of experiential learning in elementary science instruction, but there were responses that a lot of preparations for the progress and efforts were needed. Therefore, if instructional materials and teaching materials for experiential learning are given, it is confirmed that the intention of using is increased. And the results were analyzed and the experiential sites were categorized into 12 types. We could present basic data that can diversify not only the science museum but also science related experiential places. We developed a learning program related to 'The Liquid and Gas' unit of the third grade, And 'Life unit of Plant' unit of the third $4^{th}$ grade. Through this study, we intend to help science experiential learning to be activated and student - centered experiential learning to be realized.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.357-363
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• 2003

The aim of this work is the synthesis of a-C:H films from methane gas using surface spark discharge at the atmospheric pressure. Properties of these films have been investigated as functions of energy W delivered per a methane molecule in the discharge. The method enables the coatings to be deposited with high growth rates (up to $100 \mu\textrm{m}$/hour) onto large-area substrates. It is shown that the films consist of spherical granules with diameter of 20∼50 nm formed in the spark channel and then deposited onto the substrate. The best film characteristics such as minimum hydrogen-to-carbon atoms ratio H/C=0.69, maximum hardness $H_{v}$ =3 ㎬, the most dense packing of the granules and highest scratch resistance has been obtained under the condition of highest energy W of 40 eV. The deposited a-C:H coatings were found to be more soft and hydrogenated compared to the diamond-like hydrogenated (a-C:H) films which obtained by traditional plasmaenhanced chemical vapor deposition methods at low pressure (＜10 Torr). Nevertheless, these coatings can be potentially used for scratch protection of soft plastic materials since they are of an order harder than plastics but still transparent (the absorption coefficient is about $10^4$∼$10^{5}$ $m^{-1}$ At the same time the proposed method for fast deposition of a-C:H films makes this process less expensive compared to the conventional techniques. This advantage can widen the application field of. these films substantially.y.

• The Korean Journal of Emergency Medical Services
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• v.9 no.2
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• pp.183-206
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• 2005

Nowadays, the whole world is putting in the knowledge information society by the internet which is connecting the global network. The internet enable us to see the life of the other people in real time. Most of health care professional obtain and update their new knowledge and skills through continuing education. EMTs who works five or ten shifts per day are not easy to attend continuing education session usually offered during their off-times. One of solutions to this problem would be to develop a education program which does not limit time and place. There has been increasing interest in the use of computers in medical education, but all designated facilities and teachers have no sufficient preparations for the education and training of EMT. There has been less attention to the rationale for the use and selection of applications. This article discusses an approach to the selection of medical informatics applications for the undergraduate medical curriculum. The aim of this study is to develop and evaluate a web-based continuing education program, to help EMT improve their knowledge of transfusion therapy and medical law, and to enhance their ability to contribute to the quality of patient care. The program generally was well received by EMTs. The program is a useful adjunct to the existing continuing education program. It also could be used in EMT student education and other health sciences.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.463-470
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• 2017

Currently, virtual reality contents using VR images are spotlighted since they can be easily created and utilized. But because VR images are in a state of lack of interaction, there are limitations in their applications and usability.In order to overcome this problem, we propose a new method in which 360 degree panorama image and game engine are utilized to develop a high resolution of interactive VR service in real time. In particular, since the background image, which is represented by a form of panorama image, is pre-generated through a heavy rendering computation, it can be used to provide a immersive VR service with a relatively small amount of computation in run time on a low performance device. In order to show the effectiveness of our proposed method, an interactive game of a virtual zoo environment was implemented and illustrated showing that it can improve user interaction and immersion experience in a pretty good way.