• 한국수자원학회논문집
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• 제42권6호
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• pp.505-511
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• 2009

상수관망의 노후관 교체시 신설관의 관경 결정은 상수관망의 장기적인 신뢰도 향상에 기여할 수 있는 중요한 문제이다. 그러나 대구경 관의 사용은 공사비 증가를 가져오기 때문에 적절한 관경의 결정을 위해서 대구경 관 사용에 따른 신뢰도 향상정도를 평가해야 한다. 본 연구에서는 상수관경의 변화가 상수관망의 신뢰도 향상에 미치는 영향을 평가할 수 있는 방법을 제안한다. 이를 위하여 Segment 기반의 Minimum Cutset 및 Success Mode Approach를 활용하여 상수관망의 신뢰도를 산정하였으며 신뢰도 향상을 위하여 교체해야 할 상수관과 관경을 유전자 알고리즘을 이용하여 최적해를 찾도록 하였다. 제안된 방법을 실제 상수관망에 적용한 결과 상수관을 기존의 설계와 다른 관경을 이용할 경우 비슷한 공사비로 좀 더 나은 신뢰도 향상을 가져왔다. 그러나 공사비의 증가율에 비하여 신뢰도 향상의 효과는 크지 않았다. 따라서 관경 변화 뿐 아니라 상수관망의 구조적인 보강이나 추가적인 밸브의 설치도 함께 해야 상수관망의 전체적인 신뢰도 향상이 효율적으로 이루어질 것으로 판단된다.

• 공학교육연구
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• 제17권2호
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• pp.35-41
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• 2014

This paper deals with the ways that can improve the reliability of the course evaluation system based on reformation of the system and design of user interface for the practical applications. In the reformation of the system aspect, there are the improvements of the course evaluation questionnaires and the feedback of course evaluation to the lecturers. In the design aspect, a computer screen of the graphic user interface is redesigned to reflect the reformation of the system aspect issues. The results show the effectiveness in the reliability improvement.

• 전력전자학회논문지
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• 제19권2호
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• pp.99-105
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• 2014

This paper proposes the reliability improvement of H-Bridge Multi-level (HBM) inverter. This reliability can be implemented through modularization of power circuit, distribution of controller, duplication of controller and communication, and continuous operation method in case of power cell failure for driving medium-voltage & high-power induction motor. It is shown that the modularization and expansion characteristics of the HBM inverter are improved since the individual inverter modules operate more independently when using the proposed concept. Also the fault tolerance is increased by using power cell bypass. The proposed design and control methods are described in detail and the validity of the proposed system is verified experimentally in various industrial fields.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.223-229
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• 2013

Restructuring and recent developments in the power system and problems arising from construction and maintenance of large power plants, increasing amount of interest in distributed generation (DG) source. Distributed generation units due to specifications, technology and location network connectivity can improve system and load point reliability indices. In this paper, the allocation and sizing of DG in distribution networks are determined using optimization. The objective function of the proposed method is to improve customer-based reliability indices at lowest cost. The placement and size of DGs are optimized using a Genetic Algorithm (GA). To evaluate the proposed algorithm, 34-bus IEEE test system, is used. The results illustrate efficiency of the proposed method.

• 한국정보통신학회논문지
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• 제21권6호
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• pp.1155-1160
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• 2017

본 연구는 신뢰성 향상 기반의 송풍전자장치 자동검사 시스템을 구현하기 위한 연구이다. 신뢰성향상을 위해 수동검사 시스템에서 자동검사 시스템은 전자제품 검사의 오류를 최소화한다. 송풍전자장치 자동화 검사 시스템은 제어시스템과 모니터링시스템으로 구성되어 되어 실시간으로 검사결과를 공유한다. 검사시스템의 신뢰성은 Gage R&R 분석기법을 적용하여 평가한다, 평가결과는 수동검사에 비해 풍압센서를 기반으로 검사속도 2배 이상, 측정오차 ${\pm}0.02V$, 판정 능력의 유효성 15%, 누락확률 17%, 허위경보확률 12% 등으로 향상되었다. 따라서 전자제품 자동검사 시스템은 제품 바코드와 연동시켜 데이터베이스화하면 효율적인 신뢰성 향상의 품질관리시스템으로 발전시킬 수 있다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제8권1호
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• pp.39-59
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• 2008

The performance of weapon system, based on the acceleration of advanced scientific technology, has been reinforced to the state of precision, complexion and multi-function. People have given great interest for a long time on its development, acquisition cost and enormous expense of operation/support. Under this environmental situation, this research paper proposes two kinds of implementation that can improve the RAM(Reliability, Availability, Maintainability) on weapon system. The first section is to understand all of the actual states on its reliability, in the acquisition process and to make the improvement for RAM at the milestones on the acquisition steps. The next section is to establish a defense RAM center, which will be closely cooperated with acquisition organization such as Ministry of Defense, DAPA(Defense Acquisition Program Administration), DTaQ(Defense agency for Technology and Quality) and ADD(Agency for Defense Development), etc. and to conclusively improve the RAM of weapon system in South Korea.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 2004년도 품질경영모델을 통한 가치 창출
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• pp.85-89
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• 2004

This brief paper is an application of HALT(High Accelerated Life Test) and FA(Failure analysis) to improvement of STN LCD module. Before HALT the result of environmental test is good. So, we choose the technique of HALT to evaluate reliability. After HALT and Fa, we suggest some methods to improve reliability

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.181-185
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• 2002

This paper gives an assessment criteria and reliability improvement for high frequency power supply of high efficacy electrodeless fluorescent lamp. The electrodeless fluorescent lamp system consist of electrodeless fluorescent lamp, high frequency power supply and lighting fixtures. The high frequency power supply has a shortest life at the system. Therefore It is need to assess the Failure Rate or Mean Time To Failure(MTTF) for the high frequency power supply of electrodeless fluorescent lamp system and improve the reliability at design. We suggest the assessment criteria and improve methods of the reliability on the design basis for the electodeless fluorescent system.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1760-1765
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• 2007

This paper shows a derating design approach for LED reliability improvement. The LED is widely used in display devices or circuits. The main failure of interest is defined as 100% reduction of the light output intensity of LED resulting from corrosion due to stresses, i.e. temperature and humidity. The lifetime is varied according to the stress levels under where the LED operates so that correlation of the lifetime to these stress levels over time is modeled through accelerated life testings. A derating design approach to accomplish a required reliability level of LED is proposed to determine adequate the stress levels. In the approach, $B_{10}$ life, Failure rate, Sensitivity Analysis of LED are used as a reliability metric.

• 제어로봇시스템학회논문지
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• 제15권6호
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• pp.598-603
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• 2009

The checkpointing scheme is a well-known technique to cope with transient faults in digital systems. This paper proposes an adaptive checkpointing scheme for the reliability improvement of real-time control systems. The proposed adaptive checkpointing scheme is based on the previous work about the reliability problem of an equidistant checkpointing scheme. For the derivation of the adaptive scheme, some conditions are introduced which are to be satisfied for the reliability improvement by exploiting an equidistant checkpointing scheme. Numerical data show the proposed adaptive scheme outperforms the equidistant scheme from a reliability point of view.