• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4408-4425
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• 2023

Alarm flood due to abnormality propagation is the most difficult alarm overloading problem in nuclear power plants (NPPs). Root-cause analysis is suggested to help operators in understand emergency events and plant status. Multilevel Flow Modeling (MFM) has been extensively applied in alarm management by virtue of the capability of explaining causal dependencies among alarms. However, there has never been a technique that can identify the actual root cause for complex alarm situations. This paper presents an automated root-cause analysis system based on MFM. The causal reasoning algorithm is first applied to identify several possible root causes that can lead to massive alarms. A novel root-cause ranking algorithm can subsequently be used to isolate the most likely faults from the other root-cause candidates. The proposed method is validated on a pressurized water reactor (PWR) simulator at HAMMLAB. The results show that the actual root cause is accurately identified for every tested operating scenario. The automation of root-cause identification and ranking affords the opportunity of real-time alarm analysis. It is believed that the study can further improve the situation awareness of operators in the alarm flooding situation.

• 산경연구논집
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• 제10권3호
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• pp.35-44
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• 2019

Purpose - The purpose of this study is to empirically investigate the effect of choice of cause on the purchase intention by dividing it into the situation selected by the consumer and the company. This study also examines the moderating effect of cause options diversity and company-cause fit on the relationship between choice of cause and purchase intention. This will provide the theoretical information necessary to gain an in-depth understanding of the consumer's intention to purchase the cause-related marketing campaign, and in practice, it is expected that companies will be able to obtain useful information for effective planning and execution of the cause-related marketing campaign. Research design, date, and methodology - This study's survey was carried out on the college students of university located in Shandong, China. It was from November 4-11, 2018, and a total of 440 questionnaires were distributed, with 424 collected. Of them, effective questionnaires used in the final study were a total of 400 except 24 that couldn't be used. In this study, empirical analysis was done with frequency analysis, reliability analysis, analysis of variance and simple effect analysis by using Statistics Package SPSS 20.0. Results - The results are reported below: first of all, in the cause-related campaign consumers are more willing to buy the products when they are allowed to choice the focal cause of charity than when the company selects the cause of charity. Furthermore, the positive effect of allowing consumers to choice the cause of charity (vs. company choice) on purchase intentions is greater for high cause diversity to select. Finally, the positive effect of allowing consumers to choice the cause of charity (vs. company choice) on purchase intentions is greater when perceived fit between the company and the cause charity is low. Conclusions - This study extends the scope of the consumer perspective from consumer purchase intention research to the choice of cause in the cause-related marketing. When consumers select the cause, it would be better to provide the cause charity in diversifying selection and provide options for low fit between company and cause charity.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.131-136
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• 2006

작업의 지연을 줄이거나 예방하기 위해서는 작업지연상황을 지속적으로 확인하여 작업지연을 야기하는 원인을 찾아내고 대책을 세워야 한다. 건설 프로젝트는 동일한 조건하에서도 주변 환경에 따라 결과 값이 다르게 나타나는 일회성이 강한 분야 중에 하나이다. 그래서 지금까지 이루어진 선행연구들은 작업지연기간 산정방법 또는 작업지연의 클레임 사례에 관한 연구와 프로젝트 종료 후 결과에 의한 원인을 제시한 것이 대부분이다. 따라서 공사 진행 중에 발생하는 작업지연에 대해 체계적으로 활용할 수 있는 분석방법과 절차가 필요하다. 본 연구는 작업지연 원인분석 범위를 프로젝트내의 현장관리 분야로 국한하고 작업의 투입요소에 의한 분석과 VSM을 활용한 분석으로 나눴다. 건설업에 적합한 원인분석 방법을 제안하기 위해 기존에 활용되고 있는 분석방법의 특징을 분석하고 건설업의 특징을 분석하여 건설업에 활용이 적합한 방법을 도출하고 절차를 제안하였다.

• 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.

• Safety and Health at Work
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• 제12권4호
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• pp.505-510
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• 2021

Background: Factors related to root causes can cause commonly occurring accidents such as falls, slips, and jammed injuries. An important means of reducing the frequency of occupational accidents in small- to medium-sized enterprises (SMSEs) of South Korea is to perform intensity analysis of the root cause factors for accident prevention in the cause and effect model like decision models, epidemiological models, system models, human factors models, LCU (life change unit) models, and the domino theory. Especially intensity analysis in a robot system and smart technology as Industry 4.0 is very important in order to minimize the occupational accidents and fatal accident because of the complexity of accident factors. Methods: We have developed the modern cause and effect model that includes factors of root cause through statistical testing to minimize commonly occurring accidents and fatal accidents in SMSEs of South Korea and systematically proposed educational policies for accident prevention. Results: As a result, the consciousness factors among factors of root cause such as unconsciousness, disregard, ignorance, recklessness, and misjudgment had strong relationships with occupational accidents in South Korean SMSEs. Conclusion: We conclude that the educational policies necessary for minimizing these consciousness factors include continuous training procedures followed by periodic hands-on experience, along with perceptual and cognitive education related to occupational health and safety.

• 한국안전학회지
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• 제33권1호
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• pp.16-21
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• 2018

Cause analysis of accidents associated with industrial machines and devices is essential to improve the effectiveness and the efficiency of industrial safety system in Korea. This study focuses on cause analysis of accidents associated with industrial machines and devices. In particular, analysis of abstracts of accidents which are written in descriptive format and, therefore, inherently unstructured and exhibits characteristics of big data is suggested and tested. Automatic analysis of such big data performed in this study reveals the consistent results with the manual analysis results in previous studies. Analysis results also suggest that incorporating transition from the current user-oriented indirect regulations to more manufacturer and user balanced direct regulations will guarantee more effective prevention of industrial accidents at the early stage of generation of danger.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권1호
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• pp.71-77
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• 2016

Purpose: Root cause analysis (RCA) refers to any systematic process that identifies the causes that contribute to a focus event. The immediate cause of a focus event is often a symptom of underlying causes and may not truly identify the root causes that should be identified and addressed. Currently many RCA tools are available. Different investigators use different RCA tools on different issues. No standardized or commonly agreed way to analyse root causes exists. The purpose of this study is to propose the methodology of RCA process commonly useable for various issues. Methods: The methodology of RCA process is produced based on the hybrid RCA tools. The effectiveness assessment matrix of actions through the root cause candidates is presented. Results: No single RCA technique proposed has so far covered all necessary aspects. A hybrid approach which combines the best features of various techniques is proposed. The effectiveness assessment matrix helps us to identify the root cause to correct or eliminate system vulnerabilities effectively. Conclusion: This hybrid approach and effectiveness assessment matrix can provide guidance of RCA process across many industries and situations.

• 산업공학
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• 제25권4호
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• pp.382-392
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• 2012

Reactor protection system to keep nuclear safety and operational economy of plants requires high reliability. Such a high reliability of the system can be achieved through the redundant design of components. However, common cause failures of components reduce the benefits of redundant design. Thus, the common cause failure analysis, to accurately calculate the reliability of the reactor protection system, is carried out using alpha-factor model. Analysis results to 24 operating months are that 1) the system reliability satisfies the reliability goal of EPRI-URD and 2) the common cause failure contributes 90% of the system unreliability. The uncertainty analysis using alpha factor parameters of 0.05 and 0.95 quantile values shows significantly large difference in the system unreliability.

• 한국철도학회논문집
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• 제13권4호
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• pp.455-461
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• 2010

본 연구에서는 철도운영 및 시설기관의 사고/장애 데이터를 분석하여 근본원인-사고원인-위험원에 대한 분류체계를 수립하였고, 사고유형, 사고원인, 위험원, 근본원인에 대한 패턴분석을 통해 주요 사고별로 사고에 영향을 미치는 원인이 무엇인지를 정확히 분석하여, 철도사고를 유발할 수 있는 위험원인를 근본적으로 차단하기 위해 사고원인분석 정보를 국가 및 철도운영기관 등이 활용함으로써 효율적인 철도안전정책을 수립할 수 있는 사고원인분석시스템을 개발하였다.

• 한국항공운항학회지
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• 제28권2호
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• pp.1-11
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• 2020

This study was carried out to verify how much instructor's communication skill affects the student pilot's study motivation and satisfaction. The instructor's communication styles are classified into 3 groups by pre-analysis. Three types are cooperative type, control type and professional type. Intellectual cause, performance proficiency cause, social cause and stimulation avoidance cause are extracted and analyzed for the cause of study motivation. Cooperative and control type affected all of 4 factors of student's study motivation by influence analysis. Intellectual cause affected control and cooperative type positively, especially more to cooperative type. Performance proficiency cause also had positive influence to control and cooperative type. Stimulation avoidance cause didn't appear to affect all sub-classified 4 factors of instructor's communication type. Influence analysis of student's study satisfaction from instructor's communication style showed that independent variable affected all sub factors positively. Degree of positive influence affected the control type the most, cooperative type was the 2nd, and professional type was the 3rd.