• Journal of the Korean Society of Safety
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• v.35 no.1
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• pp.18-24
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• 2020

This research conducted an the failure analysis was performed based on the failure and operation data for Seven years using the Reliability, Availability, Maintainability, and Safety(RAMS) constructed at the operation stage after the opening of the D urban railway. therefore, the risk priority was selected for failure frequency component within the door system that showed high failure. Finally, the goal was to suggest ways to improve the door system. For this purpose, the analysis of thermal characteristics of failed components such as Door Control Unit(DCU) in the door system based on the Seven-year failure analysis data of RAMS was performed. These results were applied to the main component exchange cycle of the door unit, the mean time between failure(MTBF) and mean kilometer between failure(MKBF) values of RAMS increased by 26% in 2017-2018 when the improvement measures were taken, and the MTBF value of DCU was 300,000 hours, which was a 57% improvement in reliability. The results of this thesis identify potential enhancements in reliability and improvements in maintenance of the door system that, if implemented, would contribute to train safety and reduce instances of failure in the future.

• Journal of Korean Academy of Nursing
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• v.33 no.8
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• pp.1171-1177
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• 2003

Purpose. Despite many smoking cessation programs, many patients with CAD continue to smoke or re-smoke. The processes of change and self-change for smoking cessation is emphasized. The purpose of present study was to investigate decisional balances and processes of change according to stages of change for smoking cessation in the patients with CAD. Methods. This descriptive study was performed using the self-reported questionnaires from 157 male patients with CAD who have smoking experiences. The questionnaires consisted of decisional balances toward smoking (pros/cons) and processes of change including 7 factors. Results. 45.2% of the subjects had myocardial infarction and 54.8% for angina pectoris. Major stages of change were maintenance, contemplation, and precontemplation in 62%, 14%, and 18% respectively. The mean score of pros smoking was 31.07 and cons smoking was 32.52. The mean scores of processes of change were high in all 7 factors, especially in self determination. The pros smoking in precontemplation stage was significantly higher than those in other stages. Between contemplation and precontemplation stages, processes of change showed significant differences in stimulus control, self determination, information management, and dramatic relief. Conclusion. This study suggests that decisional balances and processes of change are stage-specific. As this study, smoking cessation program in the patients with CAD must put priority on the patients group in pre-contemplation and contemplation stages, and stress self determination and dramatic relief.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.183-193
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• 2010

Well planned rehabilitation order of pipes is essential for efficient maintenance and management of Water Distribution Systems. In this study, not only deterioration rate of pipes but also structural and nonstructural failure which causes abnormal condition of WDS is considered to determine rehabilitation order. Probabilistic Neural Network is used for calculating deterioration rate at present and the importance of pipes is computed under structural and nonstructural failure by using Pipe by Pipe Failure Analysis and Effect Index. Utopian Approach, one of the Multi-Criteria Decision Making methods, is used for assessment of final rehabilitation order based on distance measure between utopian point and alternative one. Developed model in this study shows that it gives more reliable results than existing methods considering hydraulic relative importance does in application to real networks. In this point, the newly developed model, which gives advantages over existing models, can make a credible decision and simple application.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.749-758
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• 2010

Embankment Slope (or Fill Slope) is defined as artificial slope formed by the filling of soil or rocks on the original ground. Recently a lot of embankment failures and collapse has occurred due to the increase of torrential rainfall and typhoons. Embankment collapse has lead to a great loss of lives and property therefore there is a need to establish a systematic embankment slope management system that will handle the maintenance and repair of risky embankment slopes. The objective of this study is to establish an "Embankment Slope Management Method" for embankment slopes located along national highways all over Korea. The method for field investigation of embankment slopes was recommended and the system for investment priority determination was also developed. The factors that lead to the collapse of embankment slopes caused by natural calamities were also determined through the initial survey of embankment slopes located along river fronts and mountainous areas.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.1B
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• pp.22-30
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• 2007

In this paper, to achieve consistency maintenance as well as stable service execution, we build a Fault-Tolerant Object Group framework that provides both of the group management service and the load scheduling service. The group management service supports the object management such as registration and authentication, and provides two schemes for failure recovery using the service priority and the checkpointing. In the load scheduling servile, we improve the effectiveness of service execution through the reasoning process of object loads based on the ANFIS architecture. The effectiveness in the performance of the developed framework is validated through a virtual home-network simulation based on the FTOG framework.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.3
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• pp.295-303
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• 2009

In the present study, a reliability analysis calculating the probability of system failure has been performed using cut set and results of numerical analysis for unsteady flow in pipe. Especially, the probability of system failure has been evaluated regarding the effect of valve closure which is a really important activity in operation of piping system. In spite of small amount of demand, it was found that fast valve closure can generate high probability of system failure. Furthermore, it was confirmed that surge tank can reduce the unsteady effects and probability of system failure in water distribution system. From the results, it was found that the unsteady flow has a significant effect on the probability of system failure Furthermore, it was able to find which pipe or cut set has high probability of system failure. So it could be used to determine which pipe or cut set has a priority of repair and replacement. Therefore, reliability analysis regarding unsteady flow has to be performed for the planning, designing, maintenance, and operation of piping system.

• Journal of the Ergonomics Society of Korea
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• v.34 no.2
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• pp.115-123
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• 2015

Objective: The aim of this study is to find and propose the behavioral characteristic of the elderly at their living space through diary study. Background: Recent development of technology and the emergence of various IT devices is contributing to active research in smart home, services which considers the behavior characteristics of the elderly are still unable to be provided. Method: This study performed self-diary study method with ten households aged over 65 that lived in smart home. Based on these data collected from the diary study, six behavior characteristics of elderly were drawn. Results: The elderly were aware of their cognitive and physical limitations and showed fear. They are difficult to adapt in the state of the art. Their activities to acquire information were limited and were against changes, preferring to maintain the old ways. Conclusion: The result of this study, findings of behavioral characteristics of the elderly reveal that most of them spend their time on personal maintenance, socializing and leisure activities. Therefore, smart home services related to these characteristics should be considered as a top priority. Application: The results of the behavior characteristics can be utilized for planning out future smart home services and thereby contributing to increase in convenience and satisfaction of the elderly.

• Journal of the Ergonomics Society of Korea
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• v.33 no.2
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• pp.77-86
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• 2014

Objective: The purpose of this study is to grasp the fundamental structure of incident occurrence in nuclear organizations based on system thinking, and analyze how various causes are interrelated in terms of the causal loop diagram. Background: The recent domestic and overseas nuclear power plant-related incidents and accidents are directly or indirectly associated with safety culture, and thus effective plans for the improvement of safety culture are being called for. While the safety of a nuclear power plant is highly dependent upon technology and equipment, the utilization, maintenance and inspection of the technology and equipment are conducted by workers of the nuclear power plant. Method: Methodology of system thinking perspective using causal loop analysis. Results: As a result of the analysis, first, it turned out that the fundamental cause of incident occurrence in nuclear organizations is time constraint. Second, if a workload of workers increases, their adherence to regulations and procedures comes to be reduced due to time constraint. Third, it is needed, through organizational learning education, to increase actions made from thoughts considering safety as the utmost priority in advance. Fourth, it is necessary to improve professionalism by enhancing educational programs for new workers, and to develop various scenarios with which they can cope with certain situations. Application: This paper provides a base for system dynamics simulation model for future study.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.862-869
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• 2005

This study examined 233 cut slopes in Gyeongnam region; evaluated hazards and slope conditions involved in the slope; and determined the priority order for reinforcement. The conclusions are summarized in the following. (1) The slopes that need reinforcement or maintenance are 153, accounting for 65.6% of the entire slopes. Slopes with a length of $0{\sim}200m$ account for 70.9%; slopes with a height of $10{\sim}20m$ account for over 50%. (2) Slopes with slope of more than 1:0.5 account for 70.9% of the entire slopes. The steepness of the slope is owing to more rock slopes than soil slopes. (3) The percentages of rock slopes, soil slopes, complex slopes mixed with rocks and soil, and slopes comprised of igneous rocks are 54.4%, 24.9%, 20.7%, and 54.1%, respectively. (4) In the rock area occurred cave-in, plain failure, wedge failure, and overturning failure, in order. Slopes with volcanic rocks are the most unstable, while sedimentary rocks and metamorphic rocks are relatively stable. (5) When the slope height is over 20m, low grade slopes are more than 80%; leading to the conclusion that the higher the slope height is, the more unstable the slope is.

• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.914-920
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• 2014

This study was conducted on children from 10 community children centers located in northern Seoul. The quality factors of the food services of the community children centers were divided into five factors, including sanitation, food, environment, subsidiary service and staff. Analysis of the differences in the importance of factors and satisfaction with the food service quality indicated satisfaction to be higher than importance for in all the factors except 'environment'. In particular, of the food service qualities, significant differences were found between importance and satisfaction in relation to the attributes of 'food' and 'environment'. As a result of IPA of the food service qualities in community children centers, 'sanitation' was found to be in the maintenance area, 'environment' to be in the area of concentration, and the quality attributes of 'staff' and 'subsidiary service' were found to be in the low priority area. In contrast, the 'food' quality corresponded to the area of oversupply.