• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.554-559
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• 2007

The cylinder cover stud for assembling the combustion chamber components of low-speed marine diesel engine is one of the main structural components in engine. To understand the structural behavior of the stud is quite important for safe and economic design of it. In this paper, the structural behavior and design adequacy of the stud have been evaluated through strain measurement and structural analysis for the world's two largest engine types. Moreover, a feasibility study for design modification was carried out based on fatigue test and calculation. The results showed that 1) the stud experiences very high stress ratio under normal operating conditions, 2) the fatigue strength of the stud is sufficient, and 3) results from strain measurement and structural analysis were quite close each other.

• 지능정보연구
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• 제6권1호
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• pp.97-112
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• 2000

The basic idea of case-based reasoning is to solve a new problem using the previous problem-solving experiences. In this research we develop a case-based reasoning system for equipment malfunction diagnosis. We first divide the case base into clusters using the case-based clustering technique. Then we develop an appropriate case-based diagnostic system for each cluster. In other words for individual cluster a different case-based diagnostic system which uses different weights for attributes is developed. As a result multiple case-based reasoning system are operating to solve a diagnostic problem. In comparison to the performance of the single case-based reasoning system our system reduces the computation time by 50% and increases the accuracy by 5% point.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2003년도 춘계 학술발표회 논문집
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• pp.403-414
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• 2003

Periodic safety review on Kori Unit 1 has been successfully done for the first time in Korea. 11 safety factors of the review were fully evaluated in accordance with the domestic legal system. Although it is the oldest nuclear power plant in Korea, Kori Unit 1 was found to have maintained good operating conditions and continuously enhanced its safety by implementing post-TMI action plans and other safety issues, such as replacing steam generators and process/control system. It can be therefore confirmed that safe operation of Kori Unit 1 is guaranteed until next periodic safety review. Nevertheless, some corrective action items were recommended to enhance further its safety level, such as equipment qualification, additional ageing management program, strengthening of some procedures related to administration and human factor. The results of PSR can be utilized for the continued operation beyond the design life as long as the plant safety is maintained and improved. Experiences of the PSR on Kori Unit 1 can be also applied to PSR on other plants.

• Nuclear Engineering and Technology
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• 제15권1호
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• pp.41-49
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• 1983

특정 원자력발전소 안전성 계통의 신뢰도 분석을 위한 자료평가의 목적으로 전산코드를 개발하였으며 그 유용성을 입증하였다. 가압 경수로 보조급수 계통 신뢰도 분석을 위하여 개발된 전산코드를 이용하여 관련자료를 평가하였다. 이를 위하여 부품고장률의 선분포는 미국의 원자력안전성 연구보고서, 특정 발전소의 운전경험은 기 발간된 인허가자 사상보고서에서 얻었다. 분석결과 후분포는 대수정규분포 곡선에 잘 점철되며 분포의 오차인자들은 현저히 감소하는 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 A
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• pp.352-357
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• 1997

The development of very high speed train system is a complex series of interrelated tasks, many of which have some degree of uncertainty associated with the successful outcome. Successful projects recognize and provide for the major uncertainties and technical unknowns with specific development strategies. The development strategies described in this paper incorporated the experiences of the advanced countries in high speed train technologies, the current technical status of Korean industries and the operating requirements of Korean High Speed Railway.

• 한국주거학회논문집
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• 제15권1호
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• pp.1-14
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• 2004

The Purpose of this study is to analyze characteristic and satisfaction businessman's opinions about Housing Rental Business. It is also aimed to suggest profitability of Housing Rental Business by understanding current situations of Housing Rental Business. This study used focus group interview(FGI) to describe the experiences and opinions about Housing Rental Business. Questionary elements include 5 themes: 1) businessman's characteristics 2) rental housing's characteristics 3) business's operating situation 4) satisfaction 5) estimate. The analysis method of this study is quality analysis. This result might be helpful provide informations for the future Housing Rental Business.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.99-101
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• 1993

This paper presents an approach to feeder reconfiguration in order to achieve an efficient operation of distribution systems utilizing knowledge base. The optimal feeder reconfiguration in this study eliminates various abnormal states which will create feeder overloads and feeder constraint problems. and will also accomplish minimum power loss of the distribution systems under normal operating condition by means of branch exchanges to change the status of sectionalizing switches with experiences of the experts. For an effective implementation of feeder reconfiguration, a best-first tree searching strategy based on heuristics is employed to evaluate the various alternatives of load transfer. The heuristic exchange of branches results in reduction of the search space as a means of implementing the best-first searching strategy.

• 공학교육연구
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• 제23권5호
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• pp.16-25
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• 2020

This article aims to analyze the experience of designing and operating a class model linking undergraduate and graduate students in engineering education and suggest its development direction. To achieve these objectives, the undergraduate-graduate linked class model was applied to community problem-solving education and a case was analyzed. It also specifically presented the process of how we design the class model and what the actual operational performances and improvements are. This study found that undergraduate and graduate students could build integrated and horizontal cooperative relationships in their classes through undergraduate-graduate linked education and, particularly, graduate students could gain meaningful educational experiences. However, it was difficult to obtain tangible performances through the team activities of these students within a semester. In order for engineering colleges to operate undergraduate-graduate linked education, it would be necessary to provide a longer and more systematic educational environment and better curriculum. The study tried to seek specific tasks and ways to improve them.

• 한국군사과학기술학회지
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• 제11권4호
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• pp.20-28
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• 2008

Missile operating at supersonic conditions experiences considerable high temperature environments that is caused by aerodynamic heating as a result of the temperature gradient through boundary layer that surrounds it. This is one of important problems to the designer due to temperature limitation of structural materials. Because prediction of aerodynamic heating on missile needs unsteady calculation according to a flight trajectory, approximate method approach is efficient at design stage. In this paper, improved aerodynamic heating analysis scheme is introduced, which calculates heat flow and temperature by simple pressure field prediction on a missile body and fin. The prediction results are compared with measured data and MINIVER codes results.

• Nuclear Engineering and Technology
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• 제39권1호
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• pp.21-30
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• 2007

Current high-temperature gas-cooled reactors (HTGRs) are based on a closed Brayton cycle with helium gas as the working fluid. Thermodynamic performance of the axial-flow helium gas turbines is of critical concern as it considerably affects the overall cycle efficiency. Helium gas turbines pose some design challenges compared to steam or air turbomachinery because of the physical properties of helium and the uniqueness of the operating conditions at high pressure with low pressure ratio. This report present a review of the helium Brayton cycle experiences in Germany and in Japan. The design and availability of helium gas turbines for HTGR are also presented in this study. We have developed a new throughflow calculation code to calculate the design-point performance of helium gas turbines. Use of the method has been illustrated by applying it to the GTHTR300 reference.