• Journal of Applied Reliability
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• v.16 no.2
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• pp.125-133
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• 2016

Purpose: The purpose of this study is to evaluate durability of platform safety step system in railway. Method: We performed finite element analysis & durability analysis of platform safety step system with VPD (Virtual Product Development) techniques and examined the durability standard & qualification life through the rig test during no failure test time in reliability qualification test. We continued to test 1 million cycles in KRS (Korea Railway Standard) for system's robust design performance. Result: FEM analysis results are 14.9MPa & 14.7MPa of pin-joint, pivot and durability analysis result is above 1 million cycles. we calculated theoretically no failure test time 855,000 cycles and through the 1 million cycles durability rig test in KRS standard we confirmed product quality. Conclusion: This platform safety step system was designed very safe in terms of a mechanical strength & durability.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.98-103
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• 2003

Based on ASME probabilistic risk assessment (PRA) and NEI PRA peer review guidance, we evaluate a human reliability analysis (HRA) in probabilistic safety assessment (PSA) for Korea standard nuclear power plants, Ulchin Unit 3&4, to improve it performed at under design. The HRA for Ulchin Unit 3&4 is assessed as higher than Grade I based on ASME PRA standard and as higher than Grade 2 based on NEI PRA peer review guidance. The major items to be improved identified through the evaluation process are the documentation, the systematic human reliability analysis, the participitation of operators in the works and review of HRA. We suggest the guidance on the identification and qualitative screening analysis for pre-accident human errors and solve some items to be improved using the suggested guidance.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1662-1669
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• 2006

Since randomness and uncertainties of design parameters are inherent, the robust design has gained an ever increasing importance in mechanical engineering. The robustness is assessed by the measure of performance variability around mean value, which is called as standard deviation. Hence, constraints in robust optimization problem can be approached as probability constraints in reliability based optimization. Then, the FOSM (first order second moment) method or the AFOSM (advanced first order second moment) method can be used to calculate the mean values and the standard deviations of functions describing constraints and object. Among two methods, AFOSM method has some advantage over FOSM method in evaluation of probability. Nevertheless, it is difficult to obtain the mean value and the standard deviation of objective function using AFOSM method, because it requires that the mean value of function is always positive. This paper presented a special technique to overcome this weakness of AFOSM method. The mean value and the standard deviation of objective function by the proposed method are reliable as shown in examples compared with results by FOSM method.

• The Journal of Korean Obstetrics and Gynecology
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• v.18 no.4
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• pp.119-135
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• 2005

Purpose : This study was investigated, in order to improve that reliability of disease mechanism diagnosis, which were used for the object diagnosis of Oriental medicine in the dept. of Oriental OB&GY, Oriental Medical hospital of Dong-Eui University, amend to a disease mechanism item of Questionnaires and indexes of disease mechanism, we were thought that the results were more pointed to the condition of appropriate disease mechanism, as a result of put a results of Questionnaires and belongs to indexes of disease mechanism together, we　suggested to call it a　'weight of disease mechanism', because It was possible to　mark a different degrees of indexes of disease mechanism in the same points.　Methods : We analyzed the results of Questionnaires about 3354 outpatients who　had OB&GY disease in the Oriental Medical hospital of Dong-Eui University from April 2000 to March 2004. Results : 1. weight of disease mechanism is 10 score according to disease mechanism score and the standard of reliability. 2. The standard of reliability is same 11 disease mechanism item except stagnated blood, cold syndrome, dry- ness, phlegm. Conclusion : Weight of disease mechanism which show satisfaction the conditions of standard of reliability, appear the results of Questionnaires, against previous study investigated reliability of Questionnaires make it through the standard of reliability.

• The Journal of Internal Korean Medicine
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• v.43 no.1
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• pp.1-21
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• 2022

Purpose: The standard tool for the pattern identification is used for identifying patterns in patients using a questionnaire. The purpose of this study is to reorganize the standard tool for the pattern identification of gastroesophageal reflux disease (GERD) developed in 2017 and to analyze the reliability and validity of the standard tool for pattern identification by applying it to GERD patients. Methods: To reorganize the standard tool for the pattern identification of GERD developed in the previous study, we searched the literature in the main databases, OASIS (Oriental Medicine Advanced Searching Integrated System) and CNKI (China National Knowledge Infrastructure). We added the search results to the data used in the previous study and went through the reorganizing courses, such as evaluating the validity of the translation, the Delphi technique, and a small survey. After reorganization, the patients who visited the Kyunghee University Korean Medicine Center for GERD symptoms were provided the questionnaire, including the reorganized standard tool for pattern identification. We analyzed the survey results to evaluate their reliability and validity. Results: Fifty patients completed the questionnaire. Reliability analysis results showed a pattern identification match rate of 86%, Cronbach's α coefficient of 0.834, and intraclass correlation coefficient of 0.907. The Mann - Whitney U test and logistic regression were implemented to check the relations between the survey questions and pattern identification results; the Pearson correlation, compared with other scales, showed a moderate score. Conclusion: We reorganized the standard tool for the pattern identification of GERD to be updated on current issues and so that it is easily used. The analysis results of the questionnaire showed that the reorganized standard tool had high reliability and moderate validity.

• Journal of Applied Reliability
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• v.14 no.2
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• pp.114-121
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• 2014

An environmental test has been performed in order to improve the lifetime and reliability of the electrical units on aircraft. However, faults occurring in the field of aircraft have been difficult to predict and prevent, and new concepts for reliability testing are desired. Therefore, a composite reliability test sequence was proposed in the conventional studies. This study introduces test sequence guidelines based on relevant principles and considerations for electronic testing according to International Standard IEC-60068-1 and the United States Military Standard MIL-STD-810G. In addition, we analyze possible causes of failure using two-step QFD based on aircraft operation scenarios. Finally, the proposed test sequence can reproduce various and realistic failure modes for electrical units on aircraft.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.330-335
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• 2002

To estimate the reliability of the standard electric multiple unit developed by Korea Railroad Research Institute, the vehicle system composed of 4 cars is divided into 14 subsystems. The 14 subsystems are connected in series. For each subsystem except for car body and bogie, failure rate is evaluated by an optimal failure model used in reliability engineering. For car body and bogie probabilistic structural integrity analysis is carried out. The distribution of failure rate of each part and system is assumed to be exponential. The estimated MTBF of the vehicle satisfies the planned MTBF.

• Analytical Science and Technology
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• v.13 no.2
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• pp.229-233
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• 2000

The study was carried out to confirm the reliability of standard samples, low concentration $0.74mgN(NO_3)/l$, $0.58mgF^-/l$, high concentration $2.14mgN(NO_3)/l$, $1.25mgF^-/l$, on the base of quality control chart. The analytical results had the precise reliability with standard deviation of 0.010, 0.017, 0.056 and 0.019, respectively. When three persons A, B and C, who had different analytical experiences, analyzed the standard samples six times repeatedly, C person, who had more academic career and analytical experience, produced far better reliability for analytical results. Therefore, these standard samples were very suitable for external quality control test, because all persons' average values for analytical results were close to the values of prepared standard samples.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.187-189
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• 2011

Standard production unit system has been used as accumulated standard for the cost estimation of public construction projects. However, it is difficult to estimate reasonable cost due to adaptation of a uniform standard and reflect changes in the technology. The purpose of this study is to provide basic data for improvement of standard production unit system through the identifying problems and analysing its influence on enactment and/or revision work of standard production unit system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.25 no.1
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• pp.1-12
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• 2015

Objectives: The major objectives of this study are to review the U.S. Standard which affected Korean worker's Right-to-Know Standard and to propose the way of improving the reliability of MSDS and labels. Methods: To review the U.S. Standard historically, we used the Federal Register, other criteria documentation and peer-reviewed literatures. Then we analysed major issues in the historical debatement on the worker's Right-to-Know Standard. Results: Korean MSDS Standard benchmarked the U.S. Hazard Communication Standard which finally established by President Reagan in 1983. Reagan's Hazard Communication Standard was aimed to preempt States Right-to-Know Acts for chemical industry and not to improve the awareness of workers on chemical hazards. Too much protection on trade secrets and low reliability of hazard information were key problems of the U.S. Standard. Conclusions: We recommend some ways to improve Korean MSDS and Label Standard. First, A new analysis frame is needed to understand the U.S Standard. Second, hazard identification is the key element of reliable information and chemical name and CAS number should be on the label of the container. Third, trade secrets should be limited to low hazardous substances and be permitted by government before the chemical product is on the market.