• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.131-136
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• 2006

In constructing projects, there exist various kinds of work interferences, which cause a delay of the outset and completion of planned schedule because of some attributions, such as variability, uncertainty and complexity. and so schedule delay has been treated as a natural phenomenon. To reduce or prevent the schedule delay, a constant confirmation of schedule delay and a preparation of counter plans for finding out the cause structure of schedule delay should have been done. However, all this time the research has been mostly done on the calculation method or claim cases of schedule delay. Moreover, the analysis method did not consider the trait, which cause the schedule delay, in constructing projects. This paper restricts the range of the cause analysis of schedule delay to the field of site management in the projects and divides the cause structure of schedule delay into the cause objects and cause attributes of schedule delay according to the input elements. The system of classifying causes of schedule delay is examined by interviews with experts and questionnaire. Additionally, this paper analyzes the attributes of cause attributes and cause subjects and presents the analysis method and procedure of schedule delay with the application of VSM.

• Quality Improvement in Health Care
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• v.23 no.1
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• pp.11-23
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• 2017

Root Cause Analysis (RCA) has been widely used as a structured approach to investigate patient safety incidents. RCA helps identify what, how, and why something happened, therefore preventing recurrence of incidents. Since many quality tools can be used during RCA, various formats of RCA exist. If RCAs are performed incorrectly or incompletely, they are likely to produce unusable results. To address this issue, RCA software has been developed. The use of RCA software in investigating patient safety incidents may offer several advantages, such as potential reduction in learning time, shortening of the analytic process, facilitation of collection, analysis, and presentation of data and production of meaningful RCA reports. We introduced six healthcare RCA software and compared characteristics. Results from this study will enable the RCA team to choose proper RCA software.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.70-74
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• 2014

An Operating Experience Report(OER) has written about events and accidents happened at a Nuclear Power Plant(NPP). The purpose of publishing the OER is to prevent the similar event or accident repeatedly by spreading the experience of a single plant to other plants personnel. In this paper, it is analyses that the foreign NPPs' OERs on JIT published by the International Nuclear Agency(WANO, INPO, COG, BE). The analysis introduced in this paper is performed along with the various factors such as type of work, root-cause, and equipment. The root-cause analysis about the OERs shows that the Human-error is the major factor in foreign NPPs, but on the other hand equipment problem is the main part of the Domestic NPPs. The ratio of the foreign NPP's OERs on JIT according to the type of work was applied to KHNP-JIT developed nowadays for the first time in KOREA.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.9 no.1
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• pp.35-39
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• 2013

The Operating Experience Report(OER) has written about the event and accident happened at a Nuclear Power Plant(NPP). The purpose of publishing the OER is to prevent the similar event or accident repeatedly by spreading the experience of a single plant to other plants personnel. Before initiating the analysis mentioned in this paper, 2,298 review reports for the same number of OER published from 2007 to June 2012 have been written to achieve the correct and objective statistics. The analysis introduced in this paper is performed with the various factors such as year, plant type, equipment, type of work, root-cause. The root-cause analysis is showed that the equipment problem is the major factor in domestic NPPs, but on the other hand human-error is the main part of the foreign NPPs. Moreover, while the number of the man-made event is decreasing, the equipment-made event is rapidly increasing in domestic NPPs.

• Quality Improvement in Health Care
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• v.24 no.1
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• pp.9-22
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• 2018

Purpose: The purpose of this study is to develop the Korean root cause analysis (RCA) software that can be used to systematically investigate underlying causes for preventing or reducing recurrence of patient safety incidents. Methods: We reviewed the existing guidelines and literatures on the RCA in order to figure out the RCA process. Also we examined the existing RCA softwares for investigating patient safety incidents to design the contents and interface of the RCA software. Based on the results of reviewing literatures and softwares, we developed a draft version of the Korean RCA software that can be easily used in Korean hospital settings by RCA teams. Results: The Korean RCA software consisted of several modules, which are modules for identifying patient safety incidents, organizing RCA team, collecting and analysing data, determining contributory factors and root causes, developing the action plans, and guiding evaluation. Conclusion: The Korean RCA software included optimized RCA process and structured logic for cause analysis. Thus even beginners in RCA are expected to easily use this software for investigating patient safety incidents. As software has been developed with the public financial support, it will be distributed free of charge. We hope that it will contribute to facilitating patient safety improvement activities in Korea.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.709-718
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• 2019

The international nuclear industry has undergone a lot of changes since the Fukushima, Chernobyl and TMI nuclear power plant accidents. However, there are still large and small component deficiencies at nuclear power plants in the world. There are many causes of electrical equipment defects. There are also factors that cause component failures due to human errors. This paper analyzed the root causes of failure and types of human error in 300 cases of electrical component failures. We analyzed the operating experience of electrical components by methods of root causes in K-HPES (Korean-version of Human Performance Enhancement System) and by methods of human error types in HuRAM+ (Human error-Related event root cause Analysis Method Plus). As a result of analysis, the most electrical component failures appeared as circuit breakers and emergency generators. The major causes of failure showed deterioration and contact failure of electrical components by human error of operations management. The causes of direct failure were due to aged components. Types of human error affecting the causes of electrical equipment failure are as follows. The human error type group I showed that errors of commission (EOC) were 97%, the human error type group II showed that slip/lapse errors were 74%, and the human error type group III showed that latent errors were 95%. This paper is meaningful in that we have approached the causes of electrical equipment failures from a comprehensive human error perspective and found a countermeasure against the root cause. This study will help human performance enhancement in nuclear power plants. However, this paper has done a lot of research on improving human performance in the maintenance field rather than in the design and construction stages. In the future, continuous research on types of human error and prevention measures in the design and construction sector will be required.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.2
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• pp.68-75
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• 2018

A flare from an Air Force fighter was abnormally dispensed during the landing. To determine the cause of the abnormal dispensing, fracture analysis, signal analysis and reproduction experiments based on physics of failures were performed. The primary cause of the failure was analyzed to be due to an intermittent fault of an internal circuit card in the AN/ALE-40 chaff/flare dispenser by a broken lid of a capacitor, and the root cause which had derived the primary cause was considered to be an improper handling during the domestic maintenance which were changed from the overseas maintenance due to the DMSMS problem. Therefore, the overall process of the maintenance capability development system was reviewed and alternative ways that considers maintenance error decision aid(MEDA) for system improvement were suggested to prevent further failures.

• The korean journal of orthodontics
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• v.51 no.4
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• pp.241-249
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• 2021

Objective: This study aimed to evaluate the volume, amount, and localization of root resorption in the maxillary first premolars using micro-computed tomography (micro-CT) after expansion with four different rapid maxillary expansion (RME) appliances. Methods: In total, 20 patients who required RME and extraction of the maxillary first premolars were recruited for this study. The patients were divided into four groups according to the appliance used: mini-implant-supported hybrid RME appliance, hyrax RME appliance, acrylic-bonded RME appliance, and full-coverage RME appliance. The same activation protocol (one activation daily) was implemented in all groups. For each group, the left and right maxillary first premolars were scanned using micro-CT, and each root were divided into six regions. Resorption craters in the six regions were analyzed using special CTAn software for direct volumetric measurements. Data were statistically analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test with Bonferroni adjustment. Results: The hybrid expansion appliance resulted in the lowest volume of root resorption and the smallest number of craters (p < 0.001). In terms of overall root resorption, no significant difference was found among the other groups (p > 0.05). Resorption was greater on the buccal surface than on the lingual surface in all groups except the hybrid appliance group (p < 0.05). Conclusions: The findings of this study suggest that all expansion appliances cause root resorption, with resorption craters generally concentrated on the buccal surface. However, the mini-implant-supported hybrid RME appliance causes lesser root resorption than do other conventional appliances.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.58-67
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• 2021

Incident investigation is regarded as a means to improve safety performance. For the prevention of industrial accidents, measures such as providing safety education, enhancing management interest and participation, establishing a safety management system, and conducting inspection of the work site are necessary. In particular, accident investigation activities, which are an important element of safety management, help to prevent similar accidents, thereby minimizing damage and enhancing work safety. They are critical for understanding business-related incidents and the vulnerabilities and opportunities associated with them. Therefore, it is clear that accident investigation activities are important for accident prevention. The primary focus of many incident investigation processes is on identifying the cause of an event. While considerable research has been conducted on potential accident investigation tools there has been little research on including the views and experiences of practitioners in the accident investigation process. In this study, a questionnaire survey was conducted among safety managers in the domestic manufacturing/construction industry to understand the practice of accident investigation. The investigation pertained to companies' accident investigation systems, the competence of investigators, and the identification and recommendations of the cause of accidents. From the analysis results of accident investigations, investigators' competence, the difficulty level of investigations, and the root causes of accidents were identified from the viewpoint of the participants of the accident investigations. In particular, the development of standardized and simple accident investigation methods and their dissemination to companies were found to be necessary for activating the root cause of accidents. Based on this, it can be used as basic data for the development of root cause analysis investigation techniques that are easily applicable to organizations.

• ETRI Journal
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• v.36 no.6
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• pp.1023-1031
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• 2014

Failure analysis is necessary to clarify the root cause of a failure, predict the next time a failure may occur, and improve the performance and reliability of a system. However, it is not an easy task to analyze and interpret failure data, especially for complex systems. Usually, these data are represented using many attributes, and sometimes they are inconsistent and ambiguous. In this paper, we present a scalable approach for the analysis and interpretation of failure data of high-performance computing systems. The approach employs rough sets theory (RST) for this task. The application of RST to a large publicly available set of failure data highlights the main attributes responsible for the root cause of a failure. In addition, it is used to analyze other failure characteristics, such as time between failures, repair times, workload running on a failed node, and failure category. Experimental results show the scalability of the presented approach and its ability to reveal dependencies among different failure characteristics.