• 한국압력기기공학회 논문집
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• 제6권1호
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• pp.83-88
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• 2010

Domestic nuclear steam generators with Alloy 600 HTMA tubes have experienced axial cracking at eggcrate tube support plates(TSPs). The axial stress corrosion cracks were observed at the crevice between outside of tubes and eggcrate TSPs. The root cause of axial cracking was investigated by thermal hydraulic analysis and sludge distribution diagnosis. It is suggested that deposition of sludge at eggcrate TSPs could increase the outside surface temperature of tube and promote the enrichment of impurities at crevice, and thus accelerate cracking. Additionally strategy for reducing the sludge ingress to steam generators is discussed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1306-1311
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• 2006

The root cause of abnormal sound from a heat exchanger of condensate water system in a nuclear power plant is investigated by using the impact signal-processing methodology based on the Hertz theory. The predicted results for the location of impact force and the loose part size meet good agreement with the identified materials during the overhaul period in the plant. Nuclear power plants have experienced several loose parts and the frequency of the loose part will be increased along the aging of the plants. So, this analysis methodology for the impact signal will be widely utilized for the primary and secondary side of the nuclear power plant.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.199-208
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• 2005

In the calendar and the advertising catalog, the surface Is usually coated by coating polypropylene film. The delamination failure of coating film depends on surface roughness and quality of the substrate paper. In this paper, the mechanisms of delamination failure between the coating film and the paper is investigated by using the root cause analysis as one of techniques of reliability evaluation. The papers used in failure analysis are three kind products made by two domestic and one foreign companies. It found that the main causes of delamination failure between the coating film and the paper were the creation of microvoids caused by shape of filler and their growth caused by contraction of paper.

• 한국건설관리학회논문집
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• 제7권5호
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• pp.138-148
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• 2006

작업의 지연을 줄이거나 예방하기 위해서는 작업지연상황을 지속적으로 확인하여 작업지연을 야기하는 원인을 찾아내고 대책을 세워야 한다. 그래서 지금까지 작업지연기간 산정방법 또는 작업지연의 클레임 사례에 관한 연구 등이 이루어졌으나 프로젝트 종료 후 결과에 의한 분석방법이나 원인분류체계를 제시한 것이 대부분이다. 건설 프로젝트는 동일한 조건하에서도 주변 환경에 따라 결과값이 다르게 나타나는 일회성이 강한 분야 중에 하나이다. 따라서 공사 진행 중에 발생하는 작업지연에 대해 효과적으로 대처할 수 있는 분석방법과 절차가 필요하다. 본 연구는 작업지연 원인분석 범위를 프로젝트내의 현장관리 분야로 국한하고 작업지연 원인분류 체계를 투입요소를 대상으로 작업지연 원인인자와 작업지 연 원인속성으로 나눴다. 작업지 연 원인분류 체계는 전문가 인터뷰 및 설문조사를 통해 검증하고 작업지 연 원인속성 및 원인인자의 특성을 분석하고 VSM을 응용한 작업지연 원인 분석방법 및 절차를 제시한다.

• 산업경영시스템학회지
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• 제41권2호
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• pp.84-94
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• 2018

In recent years, the diminishing of operation and maintenance cost using advanced maintenance technology is attracting many companies' attention. Especially, the heavy machinery industry regards it as a crucial problem since a failure of heavy machinery requires high cost and long downtime. To improve the current maintenance process, the heavy machinery industry tries to develop a methodology to predict failure in advance and to find its causes using usage data. A better analysis of failure causes requires more data so that various kinds of sensor are attached to machines and abundant amount of product usage data is collected through the sensor network. However, the systemic analysis of the collected product usage data is still in its infant stage. Many previous works have focused on failure occurrence as statistical data for reliability analysis. There have been less works to apply product usage data into root cause analysis of product failure. The product usage data collected while failures occur should be considered failure cause analysis. To do this, this study proposes a methodology to apply product usage data into failure cause analysis. The proposed methodology in this study is composed of several steps to transform product usage into failure causes. Various statistical analysis combined with product usage data such as multinomial logistic regression, T-test, and so on are used for the root cause analysis. The proposed methodology is applied to field data coming from operated locomotive and the analysis result shows its effectiveness.

• 한국가스학회지
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• 제11권2호통권35호
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• pp.60-64
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• 2007

한국에서는 석유화학 산업의 역사가 30년 이상이 되어 시설이 노후화되기 시작하여 잠재적인 사고의 위험 가능성이 높아지고 있다. 지금까지의 석유화학 산업에서의 전통적인 위험성 평가와 시스템의 제어는 기계적인 결함에만 중점을 두었기 때문에 인간의 행동을 제어하는 것은 간과하여 왔다. 자동화 기술과 제어기술의 발전도 필요하지만 인간의 의사 결정 요소가 석유화학산업에서 사고를 예방하는데 필수적이다. 거의 모든 심각한 사고는 인간 행동과 안전 장비의 기계적인 결함이 동시에 부적당할 때 발생한다. 진보적인 인간의 신뢰성 분석 소프트웨어는 실패 데이터를 수집하고, 한국의 화학 산업에서 인간의 오류 확률을 분석하기 위해 개발되었다. 이 논문에서는 Root cause Analysis를 통한 결과와 PIF(Performance Influencing Factor) 평가 결과를 보여준다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1792-1797
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• 2007

This paper try to find root-cause of failure in a connector used in transmitting signals for throttle body control in automotives by analyzing possible failure causes and performing experiments to simulate the cable failure in field. The connector comprises fins, wires, and case moldings. The failure is due to degradation of initial clamping force required fixing fins and wires in the connector. Expansion and compression of the case molding material surrounding fins would cause the degradation. Investigations of strict initial claming force and control of thermal expansion property of the molding are required to prevent the failure.

• Safety and Health at Work
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• 제12권4호
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• pp.496-504
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• 2021

Background: With the increasing demand for industrial robots and the "noncontact" trend, it is an appropriate point in time to examine whether risk assessments conducted for robot operations are performed effectively to identify and eliminate the risks of injury or harm to operators. This study discusses why robot accidents resulting in harm to operators occur repetitively despite implementing control measures and proposes corrective actions for risk assessments. Methods: This study collected 369 operator-injured robot accidents in Korea over the last decade and reconstructed them into the mechanism of injury, work being undertaken, and bodily location of the injury. Then, through the techniques of Systematic Cause Analysis Technique (SCAT) and Root Cause Analysis (RCA), this study analyzed the root and direct causes of robot accidents that had occurred. Causes identified included physical hazards and complex combinations of hazards, such as psychological, organizational, and systematic errors. The requirements of risk assessments regarding robot operations were examined, and three case studies of robot-involved tasks were investigated. The three assessments presented were: camera module processing, electrical discharge machining, and a panel-flipping robot installation. Results: After conducting RCA and comparing the three assessments, it was found that two-thirds of injury-occurring from robot accidents, causative factors included psychological and personal traits of robot operators. However, there were no evaluations of the identifications of personal aspects in the three assessment cases. Conclusion: Therefore, it was concluded that personal factors of operators, which had been overlooked in risk assessments so far, need to be included in future risk assessments on robot operations.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2004년도 추계학술발표회 발표논문집
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• pp.180-181
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• 2004

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 추계학술발표회요약집
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• pp.193-193
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• 1998