• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2017.11a
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• pp.59-60
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• 2017

• Journal of the Korean Society for Precision Engineering
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• v.10 no.2
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• pp.190-196
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• 1993

Internal high speed grinding under several high grinding wheel speed condition has been performed in this study for the effects have analyzed and compared with the grinding power, grinding tangential force and accuracy of surface with the carbon tool steel(SK3). The following results have been obtained: (1) Under the workpiece speed constant condition, increasing the grinding speed, the tangential force is decreased, and on the contrary, accuracy of surface is improved. (2) Under the speed ratio (V$_{w}$/V$_{s}$) contant condition it is possible to increase the high machining efficiency constraint to tangential grinding force constant.ant.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.153-154
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• 2020

This study aims to find out the reason that tile adhesive(type III) for ceramic tile does not harden under some conditions especially high humidity even though long curing time. Bonding strength of adhesive between substrate and ceramic tile is evaluated depending on bonding conditions such as substrate kind(concrete, board), bonding material (tile adhesive, tile cement) and curing condition(humidity 50, 70%). Based on the results, this study aimed to establish the quality of tile adhesion strength under the relevant conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1294-1300
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• 2010

In an environment where all nodes move, the sensor node receives anchor node's position information within communication radius and modifies the received anchor node's position information by one's traveled distance and direction in saving in one's memory, where if there at least 3, one's position is determined by performing localization through trilateration. The proposed localization mechanisms have been simulated in the Matlab. In an environment where certain distance is maintained and nodes move towards the same direction, the probability for the sensor node to meet at least 3 anchor nodes with absolute coordinates within 1 hub range is remote. Even if the sensor node has estimated its position with at least 3 beacon information, the angle ${\theta}$ error of accelerator and digital compass will continuously apply by the passage of time in enlarging the error tolerance and its estimated position not being relied. Dead reckoning technology is used as a supplementary position tracking navigation technology in places where GPS doesn't operate, where one's position can be estimated by knowing the distance and direction the node has traveled with acceleration sensor and digital compass. The localization algorithm to be explained is a localization technique that uses Dead reckoning where all nodes are loaded with omnidirectional antenna, and assumes that one's traveling distance and direction can be known with accelerator and digital compass. The simulation results show that our scheme performed better than other mechanisms (e.g. MCL, DV-distance).

• Journal of the Korea Institute of Building Construction
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• v.21 no.1
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• pp.11-19
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• 2021

The aim of the research is providing a fundamental data on quality and constructability of direct tile setting method depending on various cement to sand ratio for tiling dry cement mortar. A large number of tile setting failures reported is related with the cement mortar and its construction for tiling. Because of different materials of tiles, the properties of tiling dry cement mortar, an adhesive for tiling, can influence on quality and constructability of tiling differently. Practically, the easiest way of controlling the properties of the tiling dry cement mortar is to control the proportion of cement and sand. Hence, in this research, sand to cement ratio (S/C) was controlled. Since there is no standarized method on evaluating performance of dry cement mortar for tiling, a several sensory evaluation methods were suggested and executed. According to the experiments conducted in this research, the adhesive performance of cement mortar for tiles can be different depending on the sides such as tile and substrate. Additionally, depending on S/C, finishability, initial adhesive performance, and tile shifting resistance can be changed for ceramic tile. Therefore, under the conditions of this research, about 5 of S/C can be recommended for appropriate performace of tiling dry cement mortar.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.46-51
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• 2007

The 22.9kV/630A superconducting fault current limiter (SFCL) is developed by the KEPRI-LSIS collaboration group. This resistive SFCL uses three pairs of conduction-cooled current leads. When the SFCL system is in the fault mode. the current flows 20 times more than the steady state. Therefore. it is important that the current lead is designed to have the thermal stability in order to minimize the heat input of the cold-end. This paper presents the design and performance results of a pair of conduction-cooled brass current leads considering both cases that the SFCL system operates at the steady state and the fault current.

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.62-66
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• 2007

Electromagnetic forces (Attractive and repulsive force), interacting between current leads show different tendency according to the arrangement of current leads on the top flange of the cryostat and the distance of each lead. Especially in case of high-current electric power devices or high-field magnets, optimal arrangement of current leads becomes one of the safety issues to be considered for minimizing the electromagnetic for ce acting on them. In this paper, we suggest an optimal arrangement method with three pairs of current leads for a 24kV class 650A superconducting fault current limiter (SFCL) system which has a probability of unpredicted fault currents(i.e, 20kA).

• Progress in Superconductivity and Cryogenics
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• v.9 no.3
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• pp.21-25
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• 2007

Superconducting fault current limiter (SFCL) is attractive apparatus to reduce fault current in power grid. Since it is applied to the alternating current (AC) power line, the SFCL has losses in the normal operation. Recently, coated conductor (CC) is noticeable material employed for resistive bifilar winding type SFCL in many research groups. Bifilar structure is expected to have low AC loss by magnetic field offset as compared with the single tape structure in the same length. This paper reports about characteristic of bifilar pancake type coil for SFCL application in AC loss aspect. The bifilar coil is wound using CC with facing on HTS sides each other. Transport AC loss measurement and characteristic analysis of the bifilar coil using CC have been performed at 77K. The test results are compared with the Norris equations and the test results of non-inductively wound paralleled solenoid type coil which is suggested and tested in this group at present.

• Journal of the Korean Society of Food Culture
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• v.3 no.1
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• pp.7-16
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• 1988

An epigraph is an inscription mainly on a metal or stone monument, but some cases on bones or tortoise carapaces, ceramics, and coins. The '茶' inscriptions in 251 epigraphs in Korea are on 16 monuments, one tile, and one ceramic. By kingdom 5 belongs to shilla and 13 to Korea. The first '茶' inscription in on the Changsung-Tap of Borimsa Temple in Changhung-Kun, Chullanam-Do, which was established in 884 A.D. Religiously most of them are related to Buddism. Tea was most valued among valuables like gold, perlume, beads, etc. and so bestowed by kings. The study of epigraphs shows that our tea culture had most prospered diring the Kingdoms of Shilla and Korea.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.782-783
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• 2011

국내의 전력수요는 지속적으로 성장 하고 있으며, 더불어 전력산업도 대용량화, 고밀도화하고 있고 전력계통의 규모가 커짐에 따라 고장전류도 증가하고 있기 때문에 이로 인한 사회적 경제적 파급도 점차 증대되고 있다. 또한 최근에는 친환경 및 고신뢰도의 전력계통을 갖추도록 사회적 요구가 증가하고 있다. 이에 정부와 한국전력공사는 친환경적인 초전도 케이블과 초전도 한류기라는 신기술을 전력계통에 적용하여 운전함으로써 녹색기술의 사회적 요구에 부응하고, 미래 전력산업을 선도하고자, 국내최초로 초전도 전력기기 실계통 적용을 위하여 이천 변전소 초전도 시범사업을 정부지원으로 한국전력이 주관하고 제작업체가 참여하는 방법으로 추진하고 있다. 성공적인 초전도 전력기기의 실계통 적용을 위해서는 초전도 전력기기에 대한 실계통 운영시스템이 반드시 필요한데, 본 논문에서는 이천변전소에서 설치 운영될 22.9kV 초전도케이블과 22.9kV 초전도한류기의 실계통 병입과 관련하여 국내전력계통에서 운영하고 있는 SCADA 시스템과 호환할 수 있도록 계통운영자 관점에서 설계한 국내최초 초전도기기 실계통 운영모니터링시스템을 소개하고자 한다.