• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.305-306
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• 2008

최근 인구 집중현상에 따른 대도시의 전력수요 증가 및 환경적 요인으로 인하여 가공선로의 일부가 지중으로 건설되는 가공 및 지중 혼합 선로가 지속적으로 증가하고 있는 추세이다. 이는 국내뿐만 아니라 전력 선진국 및 신흥 공업국 등의 전 세계 여러 나라에서도 마차가지이다. 한편, 국내 전력산업계의 해외진출 기회가 늘어나고 있으나 해외 전력계통에 대한 기술적 검토 자료가 빈약하여 관련 자료의 확충이 절실히 필요한 실정이며, 가공선로가 아닌 지중선로 특히 지중-가공 혼합선로에 대해서는 기술검토 자료가 전무한 형편이다. 따라서 본 논문에서는 국내 전력기업이 중국과 같은 해외사업 진출시 기술 자료로 활용할수 있도록 중국의 기간 송전망으로 되어있는 220kV 혼합송전선로를 대상으로 EMTP/ATP 시뮬레이션을 통하여 지락고장시 접지방식에 따라 발생 과전압을 검토하여 적절한 접지방식을 찾고자 한다.

• Journal of the Korean Geotechnical Society
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• v.16 no.2
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• pp.125-134
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• 2000

지반이 산업용 기름으로 오염될 때 지반의 강도변화 특성을 연구하기 위하여 모래와 실트질 모래 및 카오리나이트를 대상으로 함수비아 함유비를 변화시키며 다짐실험, 투수실험, 비배수상태에서 삼축압축실험을 실시하였다. 실험결과에 의하면 밀도가 같은 모래의 경우는 기름을 혼합하였을 경우가 물을 혼합하였을 경우에 비해 약 7%정도 전단 강도가 떨어지고 실트질 모래와 카오리나이트 경우는 기름을 혼합하였을 경우가 물을 혼합하였을 경우에 비해 점토입자와 기름의 화학적, 물리학적인 상호 작용으로 5~15%정도 강도가 증가하는 현상을 보였다. 일반적으로 산업용 기름 유출에 따라 토양오염 및 수질오염으로 동.식물에 큰 영향을 주고 있으나 토질역학적 거동은 초기 상태 및 모래에서는 전단 강도가 감소하였으나 점성토의 경우는 기름 유출 또는 유입에 따라 응집성, 부착성이 생겨 강도증가 현상을 가져와 큰 문제점이 없는 것으로 판단된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.66-70
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• 2003

In this paper a plannar singly balanced diode Miter for 24GHz band application is designed and implemented using a microstrip line and two schottky barrier beam lead mixer diodes. The implemented mixer have a conversion loss of 6 [dB], LO/RF isolation of 23 [dB], input 1dB compression point of 4 [dBm]. this diode mixer would be useful for homedyne radar.

• Journal of the Korean Data and Information Science Society
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• v.26 no.2
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• pp.313-322
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• 2015

A mixture distribution of a discrete uniform or degenerated distribution and two binomial distribution is proposed and a method of obtaining the maximum likelihood estimates of the parameters is provided. For the proposed model simulation studies were conducted to see performance of the maximum likelihood estimates and a mixture of a degenerated distribution and two binomial distributions was applied to fit a lecture evaluation data to show a good result.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.118-120
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• 2003

유무선 인터넷 기술의 발달로 인해, 네트워크 전반에 걸쳐 산재해 있는 개인 정보에 대한 공유 및 교환에 대한 요구가 점차로 증가하고 있다. 본 논문에서는 이동에이전트 기반의 peer-to-peer(P2P) 네트워킹을 위한 새로운 기법이 설계되고 구현된다. 설계된 시스템은 이동에이전트를 사용함으로써, 냅스터 및 그 누텔라로 대표되는 기존의 혼합형 P2P와 순수형 P2P에서 발생하는 문제점들을 보완시킨 새로운 기법이며, 혼합형과 순수형 모두에 적용이 가능하다. 또한 분산 정보 공유 및 교환을 위한 응용 개발의 용이함을 위해 다양한 고급의 AH들을 제공하고 있다.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.778-787
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• 2022

This study was performed to obtain basic data in relation to instructional design and teaching strategy according to instructional modes. For the purpose of this study, participants evaluated the qualities of the instructions they attended and the results of the evaluation were compared according to 4 instructional modes(content class, online real-time class, online and face-to-face mixed class, and face-to-face class). As a result of the study, there were differences in the evaluation regarding the appropriateness of the course according to instructional modes. That is, satisfaction with lecture progress was lower in the online real-time classes than in content classes, mixed classes, and face-to-face classes. As a result of the descriptive lecture evaluation analysis, in the content class type, students answered that they were satisfied with the easily understandable and interesting explanations. In the case of the online real-time classes, it was found that they were satisfied with thorough preparation and effective communication. In the mixed class type, they said they were satisfied with the systematic class and passionate lecture, and in the face-to-face classes, the pleasure of interaction and the enthusiasm of the instructor were identified as the main reasons for satisfaction. It was analyzed that the satisfaction characteristic commonly derived from the four class types was the enthusiasm of the instructor. The results of this study are expected to provide implications for instructional design and teaching strategy establishment according to each instructional mode.

• Journal of the Korean GEO-environmental Society
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• v.10 no.3
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• pp.5-12
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• 2009

This study presents static and dynamic strength of coal ashes collected from disposal site of power plant. Main compositions of coal ashes were bottom ashes. In order to evaluate static and dynamic characteristics of coal ash, NGI direct-simple shear tests, cyclic simple shear tests and direct shear tests were conducted. The strengths of coal ashes from those tests were compared to those of sands. Bottom ashes among coal ashes used for this study were classified as sand from the grain size distribution and show higher strength properties than the sands. For utilization of coal ashes in civil engineering project, mixing coal ashes with sandy soil using batch plant is inconvenient and the cost is higher than the spreading sand layer and coal layer alternately. In order to simulate both mixing type and layered type construction, sands and coal ashes were mixed with volume ratio 50:50 and prepared sand and coal ash layers alternately with the same volume ratio. From the tests mixed coal ashes-specimen shows slightly higher static and cyclic strength than the layered specimen at the same density. The higher strength seems due to the angular grain of bottom ashes. The cyclic stress ratio at liquefaction decreases rapidly as the number of cycle increases at mixed specimen than that of layered specimen.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.207-213
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• 1992

In this study, the strength and durability of compacted coal ash with proper mixing ratio of fly ash to bottom ash, such as 5:5 or 6:4, are examined for use of highway embankment and subgrade materials. Right after compaction, the strength of bituminous mixed coal ash is greater than that of anthracite mixed coal ash. The distinguished increase of strength with curing time is observed only in Ho-nam mixed coal ash that contains a lot of free lime, and the strength increase with curing time are not seen or little in the others. The durability in sinking test is good also in Ho-nam mixed coal ash, but satisfactory by adding 2% cement in the others. And it is seen that the effects of the strength increase with adding cement are greater in coal ash with proper mixing ratio than in fly ash or bottom ash respectly.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.87-93
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• 2013

Recently, the amount of the mineral admixture including fly ash and ground granulated blast-furnace slag was increased for the purpose of $CO_2$ gas emission reduction in the concrete industry. However, in the case of korea, estimation model of strength development in concrete structural design code was prescribed a constant value according to cement type and curing method about the portland cement. therefore, the properties of strength development according to time of concrete using fly ash and ground granulated blast-furnace slag does not reflected estimation model of strength development. Accordingly, this paper was evaluated strength according to time on the concrete strength range using fly ash and ground granulated blast-furnace Slag and the strength development constant ${\beta}_{sc}$ of concrete according to the kind of the mineral admixture and mixing ratio was proposed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.633-640
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• 2011

In this study, the stabilization of an edge flame and the intensity variation of a diffusion branch were investigated using a multi-slot combustor under conditions of high temperature and small fuel-concentration gradient (FCG). The combustor consists of three narrow channels: a quartz channel and two side-heating combustors. For the accuracy of this experimental study, quantitative analysis was carried out for each boundary condition. Stable edge flames could be observed under high-temperature conditions by controlling the FCG and fuel dilution ratio. Moreover, it was found that the intensity of the diffusion flame was increased by increasing the temperature of the mixture. On the contrary, the intensity of the diffusion flame was decreased by increasing the dilution ratio. It was also found that a propane flame is more sensitively affected by these experimental parameters than a methane flame.