• Journal of Welding and Joining
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• 제28권1호
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• pp.77-85
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• 2010

Stainless steel sheets are widely used as the structure material for the railroad cars and the commercial vehicles. These kinds structures used stainless steel sheets are commonly fabricated by using the gas welding. Gas welding is very important and useful technology in fabrication of a railroad car and vehicles structure.However fatigue strength of the gas welded joints is considerably lower than parent metal due to stress concentration at the weld, fatigue strength evaluation of gas welded joints are very important to evaluate the reliability and durability of railroad cars and to establish a criterion of long life fatigue design. In this paper, $({\Delta}{\sigma}_a)_R-N_f$ curve were obtained by fatigue tests. Using these results, the accelerated life test(ALT) was conducted. From the experimental results, an acceleration model was derived and acceleration factors are estimated. So it is intended to obtain the useful information for the fatigue lifetime of plug and ring gas welded joints and data analysis by statistic reliability method, to save time and cost, and to develop optimum accelerated life prediction plans.

• 한국공작기계학회논문집
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• 제12권1호
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• pp.32-37
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• 2003

Evaluation of fatigue strength on the spot welded part is very important for strength design of spot welded steel structures. In this paper, we could get the life cycle of the spot welded part using the lethargy coefficient obtained through the quasi-static tensile shear test for the specimen welded by current 10kA. The reliability evaluation of the life cycle is completed by comparing the life cycle calculated under the constant loading rate with the life cycle obtained by dynamic fatigue test. And then the result calculated by the lethargy coefficient is verified through the lift cycle calculated using the dynamic final tensile stress formula under the increased loading speed. This way can make save the time and cost in processing of predicting the life cycle of a structure.

• 대한산업공학회지
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• 제21권1호
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• pp.17-32
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• 1995

The objective of this study is to develop a general design and performance evaluation model for the system designers in the initial design phase of the integrated automatic manufacturing system based on the RAM(Reliability, Availability and Maintainability) and life cycle cost(LCC). The methodology proposed in this research includes the following two stages. First, a deterministic approach to the solution of optimal work station arrangement for the initial system configuration is considered under the assumption that the system availability is one(no failure and maintenance), and then a stochastic simulation model based on RAM and LCC is developed. Using the results of these two stage simulation, a system performance index(SPI) was developed for the performance evaluation of the proposed system. Also a computer program is developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.435-436
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• 2007

As the power industry moves towards open competition, there has been a call for methodology to evaluate power system reliability by using customer interruption costs. This paper presents an evaluation of interruption costs by industrial customer type in Korea using customer survey methodology. When various research results are examined, the customer damage survey methodology becomes much more generalized. Especially, in the case of industrial customers, it is known that the evaluation by customer damage survey is more useful. Accordingly, this paper selected the customer damage survey method to evaluate interruption costs by industrial customer type in Korea considering interruption and customer characteristics.

• 정보교육학회논문지
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• 제14권4호
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• pp.659-666
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• 2010

수행평가는 교수 학습 과정과 평가 과정을 접목시키는 데 적절한 평가 방법이고 의미 있는 평가 결과를 얻기 위해 필수적이라고 인정되고 있다. 하지만 비용과 시간의 문제, 교사의 업무 부담으로 인해 학생이 소외된 교사 주도의 평가 방법이 주로 사용되고 있고 이는 평가 결과의 신뢰성에도 영향을 미친다. 본 연구에서는 학교현장에서 이루어지는 수행평가를 효율적으로 운영하고 학생들의 학습 효과 증진을 위해 오픈 소스인 무들(Moodle)을 활용하여 웹기반 수행평가 시스템을 개발하여 적용하였다. 이를 통해 웹기반 수행평가를 시도하는 교사로 하여금 시스템 개발의 부담을 덜어줌과 동시에 무들에서 제공하는 다양한 전략을 통하여 기존 동료 평가 방식에서 제기된 신뢰성 확보 문제도 해결할 수 있었다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.867-869
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• 2012

FRUC(Frame Rate Up Conversion) 기법은 더욱 높은 품질의 단말기 또는 낮은 채널 전송율을 갖는 응용 시스템에서는 꼭 필요한 요소 기술이다. 본 논문에서는 이러한 응용분야를 위하여 양방향 대칭형 탐색에 기초한 FRUC 기법에서 생성된 움직임 보상 보간 프레임에 대하여 블록기반의 신뢰성을 평가하는 방법을 제안한다. 먼저 신뢰도를 측정할 수 있는 시간적 정합특성과 공간적 정합특성과 움직임 벡터의 균일성 분석을 통해 측정되는 비용함수를 도입하고, 비용 함수들의 조합을 통하여 실제 발생된 왜곡의 크기순과 매우 상관성이 높은 정렬 방식을 제안한다. 다양한 모의실험을 통하여 제안 방식은 높은 왜곡 블록을 찾는데 효과적임을 보인다. 또한, 제안방식은 FRUC기법과 더불어 분산 비디오 부호화 기술에도 효과적으로 활용될 수 있을 것으로 기대된다.

• 한국의류학회지
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• 제30권7호
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• pp.1066-1077
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• 2006

The purpose of this study was to investigate the effect of store attributes, purchasing experience, clothing product evaluation and store trust on store loyalty of discount store. With convenience sampling, the research was surveyed to women who have bought apparels at the discount store. The 374 responses were analyzed by frequency analysis, factor analysis, reliability test, t-test and hierarchical regression analysis. The results were as follows. First, the clothing product evaluation was significantly affected by the variety of products, reliable advertisement, good display, convenient store location, purchasing cost and buying experience of PB apparel. Second, the trust of discount store was significantly affected by store attributes, purchasing experience and clothing product evaluation. Third, the discount store loyalty was analyzed as fashion store loyalty. The store loyalty was affected by purchasing experience and clothing product evaluation. Fourth, the clothing product evaluation and store loyalty were appeared high by people who had bought PB, PNB and trendy apparels.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권7호
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• pp.500-504
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• 2009

전통적인 소프트웨어 공학 관점에서 소프트웨어의 비 기능적 요구사항 중 하나인 신뢰성은, 소프트웨어 개발 프로세스에서 마지막 단계인 통합 테스트 이후에 검증이 가능하다. 그러나 이것은 소프트웨어 개발에 있어서 많은 위험성과 개발 비용을 발생시킨다. 따라서 본 논문에서는 소프트웨어 개발 초기 단계에서 수학적인 분석 모델을 통해 신뢰성을 분석할 수 있는 방법을 제안한다. 소프트웨어의 신뢰성분석을 위하여 본 논문에서는 다음 두 가지를 제안한다. 첫째로, 계층형 큐잉 패트리넷을 이용하여 신뢰성 분석을 위한 소프트웨어 모델링 방법론을 제안한다. 둘째로, 완성된 계층형 큐잉 패트리넷 모델로부터 신뢰성 분석을 위한 마코프 리워드 모델(Markov Reward Model)을 유도해내는 방법에 관하여 제안한다. 본 논문의 유효성을 검증하기 위하여, 화상회의 시스템 개발사례에 적용하였다. 본 연구 결과를 통해 소프트웨어 신뢰성의 정량적인 분석이 가능하다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.51-54
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• 1991

As a transmission network planning should be optimal in the sense of technology, economy and reliability, an adequate optimization tool is required. The simulation model is valuable at this case. It enables the planner to detect the weak points of the system by providing the planner with unsupplied powers, operating cost, and active losses at each substation node and each line. This paper represent the example of application of simulation model for power system planning.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.37-40
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• 2008

We have concentrated on the performance improvement of each part for durability, safety and cost of high pressure storage system for fuel cell vehicle so far. But for the mass production of fuel cell vehicle, it is necessary to evaluate durability and safety in system module. We built the standard to evaluate and collision safety of high pressure storage system for fuel cell vehicle, and could verify reliability of high pressure storage system.