• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.441-452
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• 2018

Purpose: The purpose of this paper is to study quantitative risk grade assessment for objective government quality assurance activities based on risk management in initial mass production for weapon systems. Methods: The Defense quality management regulations and foreign risk assessment documents are referred to analyze problems performing quality assurance actives. The failure rate data, maintainability and cost of products have been studied to quantify the risk Likelihood and impact. The analyzed data were classified as risk grade assessment through K-means Cluster Analysis method. Results: Results show that a proposed method can objectively evaluate risk grade. The analyzed results are clustered into three levels such as high, middle and low. Two products are allocated high, eleven low and seven middle. Conclusion: In this paper, quantitative risk grade assessment methods were presented by analyzing risk ratings based on objective data. The findings showed that the methods would be effective for initial mass production for weapon systems.

• Journal of Korea Water Resources Association
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• v.56 no.2
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• pp.115-124
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• 2023

Currently, as the frequency of extreme weather events increases, the scale of damage increases when extreme weather events occur. This has been providing forecast information by investing a lot of time and resources to predict rainfall from the past. However, this information is difficult for non-experts to understand, and it does not include information on how much damage occurs when extreme weather events occur. Therefore, in this study, a risk matrix based on heavy rain damage rating was presented by using the impact forecasting standard through the creation of a risk matrix presented for the first time in the UK. First, through correlation analysis between rainfall data and damage data, variables necessary for risk matrix creation are selected, and PERCENTILE (25%, 75%, 90%, 95%) and JNBC (Jenks Natural Breaks Classification) techniques suggested in previous studies are used. Therefore, a rating standard according to rainfall and damage was calculated, and two rating standards were synthesized to present one standard. As a result of the analysis, in the case of the number of households affected by the disaster, PERCENTILE showed the highest distribution than JNBC in the Yeongsan River and Seomjin River basins where the most damage occurred, and similar results were shown in the Chungcheong-do area. Looking at the results of rainfall grading, JNBC's grade was higher than PERCENTILE's, and the highest grade was shown especially in Jeolla-do and Chungcheong-do. In addition, when comparing with the current status of heavy rain warnings in the affected area, it can be confirmed that JNBC is similar. In the risk matrix results, it was confirmed that JNBC replicated better than PERCENTILE in Sejong, Daejeon, Chungnam, Chungbuk, Gwangju, Jeonnam, and Jeonbuk regions, which suffered the most damage.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.4
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• pp.162-167
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• 2008

FMEA (failure mode and effect analysis)is a widely used technique to assess or to improve reliability of product not only at early stage of design and development, but at the process and service phase during the product life cycle. In designing a service system, this study proposes a fuzzy service FMEA with the service blueprints as a tool which describes customer actions, onstage contact employees actions, backstage contact employees actions, support processes, and physical evidences, in order to analyse and inform service delivery system design. We fuzzified only two risk factors, occurrence and severity, to more effectively assess the potential failure modes in service. Proposed fuzzy risk grades are applied to Gaussian membership function, defuzzified into Fuzzy Inference System, and eventually identified the ranks on the potential fail points.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.3
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• pp.64-72
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• 2015

Risk Based Inspection (RBI) Period was proposed for highway bridges in Korea. Hazard factors affecting bridge condition deterioration were found by analyzing condition data from Highway Bridge Management System (HBMS). Certain level of correlations between those factors and condition deterioration were found. They are used to evaluate hazard score. Summarizing several hazard factors, final hazard is classified as three level;high, moderate, low. Vulnerability is assessed only by the current state of bridge. Then, risk matrix is suggested for inspection periods. Inspection periods of the bridges with grade C, D, and E are maintained the same as before. But, those of grade A and B with moderate and high hazard score are elongated to maximum 6 years while the maximum inspection period is three years at present. By adjusting inspection period according to risk assessment, it was shown that 27% of average inspection manpower can be saved.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.401-417
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• 2020

As an increasing demand for rapid railway transportation, the construction of sidetrack is inevitable to operate local and express trains simultaneously. However, the current technologies for the sidetrack construction method require a long construction period by interrupting the operation of the existing subway line, as well as cause a huge economic loss. Thus, it is necessary to study the sidetrack construction method under the special situation that the subway is in operation and to analyze the risk of the existing tunnel enlargement process for the sidetrack construction. Therefore, in this paper, the Government Complex Gwacheon station on Subway Line 4 was considered as a target station for the virtual sidetrack construction and the optimal sidetrack construction plan was derived. Subsequently, the application of risk management process was carried out in the order of identifying risk, risk response planning, performing a risk analysis, risk monitoring and control for potential risk events during the construction of sidetrack under the subway operation. A total of eight potential risk events and risk mitigation methods were selected, and a risk assessment matrix was established using the five-step risk probability and impact level criteria to perform the risk assessment including residual risks. Based on the results of the risk assessment, the risk grade and the reduction effect of each risk mitigation method were confirmed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.585-592
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• 2017

Most sewer lines buried in the city are likely to be collapsed due to serious aging. Also, due to the high concentration of development and high population density and traffic, the collapse of the sewer will cause enormous social and economic damage. Therefore, proactive maintenance is required to prevent accidents caused by deteriorated sewer pipe. In order to utilize limited budget effectively, risk-based prioritization methods should be proposed that simultaneously consider the consequence of failure and the probability of failure. In this study, the method of risk-based prioritization of sewer was examined by reviewing various cases of overseas studies and applied to the urban sub-catchment. First, the impact factors that can be secured through the sewer GIS DB in Seoul were derived, and the weight, sub-criteria, and impact score of each impact factor were determined and the consequence of failure was calculated by weight sum method. In addition, the probability of failure was calculated by dividing the service life by the estimated useful life, and the consequence of failure and the probability of failure were classified into five grades by the Jenks natural breaks classification method. The prioritization method was applied to sub-catchment in the Seoul to derive a risk matrix and a risk grade. As a result, 26% of all subjects were selected as the inspection priority subjects with 4-5 risk grade. Therefore, using the risk-based CCTV prioritization methodology, it will be possible to systematically determine the objects that need investigation first.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.170-177
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• 2008

Purpose : To evaluate usefulness of MR imaging after serial brain US in the high-risk neonates before discharge of the neonatal intensive care unit. Materials and Methods : Retrospective comparison of 412 US and 121 MR scans in 121 neonates and young infants were performed. Grading of germinal matrix/intraventricular hemorrhage (GMH/IVH) was performed and presence of intracranial hemorrhage other than GMH/IVH and parencyma lesions was also analyzed. Results : Among the 242 lateral ventricles, Seven GMH and 46 IVH were additionally detected by MRI. On the other hand, 30 GMH were only detected by US. US demonstrated Grade 1/2/3/4 GMH/IVH in 24/8/13/0 ventricles each, while each grades were identified in 3, 49, 10, 2 ventricles on MR images. Other intracranial lesions additionally detected on MR images were cerebral hemorrhage (n=4), cerebellar hemorrhage (n=4), extraaxial hemorrhage (n=8), diffuse excessive signal change of the white matter (n=72), non-cavitary lesion (n=4), encephalomalacia (n=2), and ventriculomegaly (n=5). Conclusion : MR imaging could be an excellent complimentary study after serial brain US for additional detection of the intracranial pathology, particularly IVH and white matter lesions, though US would be better in follow-up of GMH in some neonates.

• Journal of the Korean Society of Earth Science Education
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• v.14 no.2
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• pp.159-172
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• 2021

This study is an action study that plans a instructional strategy for improving experimental activities and interactions in online science classes and suggests improvement plans based on the results. To this end, from July 7 to September 9, 2020, the 'Earth and the Moon' unit class was conducted for 20 6th grade elementary school students located in G Metropolitan City. For the class, smart devices and alternative experiments were planned in the experimental activity category, and an online chat room and Q&A strategy were planned in the interaction category. Among the collected data, class activity papers, homework assignments, reflection journals, online conversation contents, and Q&A contents were input into the matrix and analyzed by writing analytical texts. As a result of the implementation, smart devices and alternative experiments provided opportunities for exploration, but there was a risk of misconception formation and hindered experimental activities. The online chat room and Q&A provided opportunities for communication and examination and feedback on scientific concepts. Through this action study, the researcher was able to reflect on the class while writing class reflection notes, and suggested the role of smart devices in terms of the effectiveness and efficiency of science classes.