• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.326-328
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• 2005

In order to reduce the capital and overall operating cost of a fuel-cell system, a high-efficiency fuel-cell power inverter with a simple framework is required. The high-order two-inductance two-capacitance (LLCC) resonant technique is adopted in this study to implement a low-frequency 60-Hz sine wave voltage inverter utilized in the proton exchange membrane fuel-cell (PEMFC) system. The methodology for inverting dc voltage into low-frequency ac boltage is usually generated by the pulse-width-modulation (PWM) technique. However, the PWM-type inverter output has high-frequency harmonic components. Although an adequately designed filter could be utilized to overcome this problem, there are still some undesirable effects introduced by the high-frequency switching loss, electromagnetic-interference, harmonic current, and load variation. A novel power inverter via the LLCC resonant technique is designed for inverting dc voltage into 60-Hz ac sine wave voltage in the PEMFC system. This circuit scheme has the merits of low harmonic components, soft switching, high efficiency, and simplified implementation. The effectiveness of the proposed resonant inverter used for the PEMFC system is verified by numerical simulations and experimental results.

• 정보관리학회지
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• 제15권2호
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• pp.69-88
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• 1998

어떤 조직체에서나 컴퓨터 네트워크 서비스에 관련된 문제는 기술적, 조직적, 인간적인 것 등 여러 가지 복잡한 요인들과 연관되어, 정보서비스 향상을 위한 문제점 파악과 그 해결 방법을 찾아내는데 어려운 점이 있다. 본 논문은 대학에서 컴퓨터 네트워크를 이용한 정보서비스를 계획 및 운영하는데 있어서 필요한 정보시스템 모형을 개발해 본 것이다. 모형개발을 위한 효과적인 방법론으로서는 최근 관심을 끌고 있는 소프트시스템 방법론을 적용하였다. 본 시스템 방법론의 일곱 단계가 전개되면서 최적의 정보시스템 모형이 개발되었는데 이는 대학 등 교육기관 뿐만 아니라 영업기관, 공공기관 등의 조직에서도 응용될 수 있겠다. 연구 결과로 개발된 네 가지 주요 시스템은 네트워크 시스템, 유지 보수 시스템, 모니터 시스템, 교육 훈련 시스템이다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.105-105
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• 2003

Theoretical studies have been performed for drainage and filtration characteristics, low consolidation rate of sandmat and prefabricated horizontal and vertical drain. Discussion on quality control and methodology, cost analysis for sandmat and prefabricated horizontal drains were performed.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.387-392
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• 2005

본 논문에서는 LCD 공정관리에서 SPC 시스템의 주요내용 및 운영방법론을 논하고자 한다. 주요내용으로는 실시간 프로세스 모니터링 방법론, 유의차분석 방법론, 이상데이터의 분석, 공정능력의 분석, 관리도 및 결과의 조회 등을 들 수 있다. 또한, TFT-LCD 공정을 크게 Fab 공정인 TFT 공정, LC 공정 및 Module 공정으로 나누어 각 공정에서의 중요한 특성과 관리방법론을 제시하고자 한다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1993년도 봄 학술회 논문집
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• pp.41-48
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• 1993

The 2nd phase of Seoul Subway, Lines 5,6,7 and 8, is in progress. To reduce the surface traffic congestion during construction the greater part of the system has been engineered by bored tunnelling. The current tunnelling methodology is based on the New Austrian Tunnelling Method. Serveral collapses have been reported to date. Most of the collapses took place in the area forwed with soft ground. The modes and causes of the collapses were progressive failures in the unsupported surface and sliding failures due to the unfavourable joint direction. The major causes turned out to be the weakness of ground and the sudden influx of ground water from the surface. Some measures to prevent the failures are also presented. To ensure the safe tunnelling ghrough the soft ground the unsupported excavation area has to be minimized and closed as early as possible. Additional support measures such as supporting core, sealing shotcrete, forepoling, spread footing, face rock bolting and grouting should be employed as well depend on ground conditions.

• 대한치과기공학회지
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• 제42권3호
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• pp.298-305
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• 2020

Here, we studied the sports mouse guard as an oral device system, to minimize the sports related facial and dental injuries, jawbone fracture and brain injury, and by layering the hardened sheets for improving the activity performance and stable wearing. By pressuring and layering 2 soft- and 1 hard-layers of ethylene vinyl acetate (EVA) thermoplastic materials, for a category of martial art, record sports and leports, here we introduce a methodology for thickness control of layers to protect the teeth and oral structure. A personally customized mouse guard optimized for sports by layering a mixture of soft and hardened sheets is not easily detached during the sporting activity, easy to breathe through, comforts to wear, and also improves the sporting record. A designed EVA thermoplastic material for individual sports is used as the mouth guard, which is stably attached, easily removed, and convenient for breathing through the mouth.

• 항공우주시스템공학회지
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• 제1권1호
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• pp.60-66
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• 2007

The importance of software development in the integration of an avionics system is continuously increasing. And we can expect enlarged soft ware portion in the system integration for the more intelligent, reliable, and automated avionics system. For an avionics system software development the selection of a real-time operating system and internal avionics data bus protocol is very important from the viewpoint of the integration with the system hardware. In this paper, we present current trend of an avionics system software development including software development methodology, software development process, and international software process assessment improvement model.

• 한국지반신소재학회논문집
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• 제7권2호
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• pp.7-13
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• 2008

토목공사를 수행함에 있어 토목섬유가 적용된 이후 토목섬유의 손상에 대하여 많은 관심이 되어왔다. 토목용 섬유제품인 지오텍스타일은 주변 환경조건에 노출되는 고분자 재료로서 분리, 보강, 여과, 배수 등의 기능을 가지며 현재 제방공사, 해안 하천의 호안공사, 간척공사 또는 도로, 철도 노상 안정 등의 분야에 광범위하게 이용되고 있다. 본 연구는 토목섬유매트의 현장 적용시 설계방법을 분석하였고, 설계시 고려되는 인장, 파열, 꿰뚫림, 인열강도의 관계와 더불어 인장강도와 봉합강도의 상관성에 대하여 평가하였다. 또한, 토목섬유매트 적용시 유효봉합율과 시험방법의 적정성, 경제성 등이 고려된 시공방법론 등을 제시하였다.

• Nuclear Engineering and Technology
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• 제55권3호
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• pp.839-849
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• 2023

The development of automation technology to reduce human error by minimizing human intervention is accelerating with artificial intelligence and big data processing technology, even in the nuclear field. Among nuclear power plant operation modes, the startup and shutdown operations are still performed manually and thus have the potential for human error. As part of the development of an autonomous operation system for startup operation, this paper proposes an action coordinating strategy to obtain the optimal actions. The lower level of the system consists of operating blocks that are created by analyzing the operation tasks to achieve local goals through soft actor-critic algorithms. However, when multiple agents try to perform conflicting actions, a method is needed to coordinate them, and for this, an action coordination strategy was developed in this work as the upper level of the system. Three quantification methods were compared and evaluated based on the future plant state predicted by plant parameter prediction models using long short-term memory networks. Results confirmed that the optimal action to satisfy the limiting conditions for operation can be selected by coordinating the action sets. It is expected that this methodology can be generalized through future research.

• Earthquakes and Structures
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• 제1권1호
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• pp.69-91
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• 2010

Current seismic design codes do not contemplate explicitly some variables that are relevant for the design of structures subjected to ground motions exhibiting large energy content. Particularly, the lack of explicit consideration of the cumulative plastic demands and of the degradation of the hysteretic cycle may result in a significant underestimation of the lateral strength of reinforced concrete structures built on soft soils. This paper introduces and illustrates the use of a numerical performance-based methodology for the predesign of standard-occupation reinforced concrete ductile structures. The methodology takes into account two limit states, the performance of the non-structural system, and in the case of the life safety limit state, the effect of cumulative plastic demands and of the degradation of the hysteretic cycle on the assessment of structural performance.