• International Journal of Railway
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• 제1권3호
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• pp.94-98
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• 2008

Static inverters are essential devices onboard of rolling stock. State-of-the-art static inverters have an impact on both rail infrastructure and vehicle maintenance due to their new topology with new features. The paper describes two important aspects as examples of new features available in state-of-the-art static inverters: active input current control and the effects on the rail infrastructure as well as the detection of the state of charge and the state of health of batteries to simplify vehicle maintenance.

• Advances in aircraft and spacecraft science
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• 제2권4호
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• pp.391-401
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• 2015

Crashworthiness design and certification have been and will continue to be the main concern in aviation safety. The effects of roll angles on fuselage section crashworthiness for typical civil transport category aircrafts were investigated. A fuselage section with waved-plates under cargo floor is suggested, and the finite element model of fuselage section is developed to simulate drop test subjected to 7 m/s impact velocity under conditions of 0-deg, 5-deg, 10-deg and 15-deg roll angles, respectively. A comparative analysis of failure modes, acceleration responses, and energy absorption of fuselage section under various conditions are given. The results show that the change of roll angles will significantly affect fuselage deformation, seat peak overloads, and energy absorption. The crashworthiness capability of aircraft can be effectively improved by choosing appropriate landing way.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.711-712
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• 2011

• 대한산업공학회지
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• 제36권2호
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• pp.108-116
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• 2010

The maintenance of a deteriorating system is often imperfect. Previous studies have shown that the imperfect preventive maintenance (PM) can reduce the wear out and aging effects of deteriorating systems to a certain level between the conditions of as good as new and as bad as old. In this paper, we employ the concept of the improvement factor in investigating two optimal PM policies; failure limit policy and periodic PM policy. We redefine the improvement factor model as a function of the cost of PM, using this concept, we derive the conditions of optimal PM policies and formulate expressions to compute the expected cost rate. Based on this information, the determination of the maintenance policies which minimize the cost rate is examined. Numerical examples for the Weibull distribution case are also given.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.454-459
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• 2003

The process of determining whether, when, where and how to intervene, of deciding on optimum allocation of resources and minimizing the cost is a very complex problem: different track sections tend to behave differently under the effects of loading; decision-making processes for maintenance work are closely interrelated technically and economically; decision-making for maintenance plans is based on a large quantity of technical and economic information, extensive knowledge and above all experience. For that reason, It is considered very important to develope objective and computer-aided decision-making support system for track maintenance plan. On this paper, we reviewed ECOTRACK system and present the plan of develope decision-making support system for track maintenance appropriate to local condition.

• 대한안전경영과학회지
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• 제19권3호
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• pp.49-58
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• 2017

This paper suggests a specific model that could efficiently improve the interaction and the interface between MES(Manufacturing Execution System) server and POP(Point of Production) terminal through electronic document server and electronic pen, bluetooth receiver and form paper in disassembly and process inspection works. The proposed model shows that the new method by electronic document automation system can more efficiently perform to reduce processing time for maintenance work, compared with the current approach by handwritten processing system. It is noted in case of the method by electronic document automation system that the effects of proposed model are as follows; (a) While the processing time per equipment for maintenance by the current method was 300 minutes, the processing time by the new method was 50 minutes. (b) While the processing error ratio by the current method was 20%, the error ratio by the new method was 1%.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.58-65
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• 2008

본 논문은 신뢰도 기반 유지보수(RCM : Reliability-Centered Maintenance) 계획에 의한 발전설비의 유지보수주기를 평가하고 있다. 유지보수주기는 발전설비의 안정성 및 비용을 결정하기 위한 기준으로 활용된다. 본 논문에서는 설비 수명평가를 통해 확률분포를 이용한 확률론적 FMECA(Failure Mode, Effects and Criticality Analysis)에 대해 논하고, 국내 발전 설비 중 비교적 평균수명이 짧은 복합화력 발전소를 선정하여 유지보수 주기를 평가하였다. 발전소 유지보수 평가는 향후 구조 개편된 전력시장에서 유지보수계획 수립 방법의 유용한 지표로 활용 가능할 것이다.

• Structural Monitoring and Maintenance
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• 제10권1호
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• pp.25-42
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• 2023

Despite the significance of ports as critical economic infrastructure, the berth facilities usually deteriorate due to heavy loading, unloading, aging, environmental weather conditions, marine growths, and lack of efficient maintenance management. Marine berths require proactive maintenance management to limit deterioration and defects as no berth facility is maintenance-free. Thus, delay in carrying out maintenance work for the marine berths can be devastating to the operational process involving ship entry, loading, and unloading operations. The aim of this research is to coordinate both operations work, and maintenance works that take place inside the berth of a local industrial port in Saudi Arabia, by developing a novel framework that integrates both works without affecting the efficiency and functionality of the berth. The study focused on defining the operational process of the port and identifying the elements with direct and indirect effects. In addition to determining the priority for the entry of ships inside the berth, it also identified the factors involved in designing a framework that included maintenance work as a component of the monthly berth occupancy schedule. By applying a mathematical model, a framework was established, which includes all the important elements of the process. As a result of the mathematical method formulation process, a database was designed that organizes and coordinates the operations of all berths within the port. This creates time to carry out the required maintenance work monthly as well as ease of coordination with the contractors responsible for the implementation of those works.

• The Journal of Korean Physical Therapy
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• 제21권4호
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• pp.89-96
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• 2009

Purpose: This study examined the effects of manual lymph drainage (MLD) on edema and the quality of life (QOL) of lymphedema patients in the maintenance phase. Method: Forty five lymphedema patients, who had completed intensive decongestive therapy, were enrolled in this study. All subjects were assigned randomly to two groups: Experimental (MLD) group (n=23) and control (self-MLD) group (n=22). MLD by a specialist was applied with a comfortable pressure for 40~60 minutes in the experimental group and self-MLD was carried out by the control group 5 times a week for 2 weeks. The % edema and a SF-36 questionnaire were used to measure the decrease in edema and the QOL. A paired t-test was used to compare the period, and an independent T-test was used to compare experiment and control groups. Result: The % edema was significantly lower in the experimental group after MLD (p<0.05). The physical, vitality, and mental health scores of the experimental group was significantly higher than those of the control group (p<0.05). Conclusion: TMLD by a specialist in the maintenance phase is effective in reducing the % edema and enhancing the QOL of lymphedema patients. Further studies will be needed to determine if there are differences in the effects of many types of treatment methods in the lymphedema treatment.

• 한국의류학회지
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• 제43권1호
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• pp.17-32
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• 2019

This study examines the effects of SNS fashion influencer's authenticity on the followers' relationship maintenance intention and product purchase intention through the mediating role of fanship. In addition, influencer's attractiveness is proposed as a moderator affecting the authenticity on fanship; in addition, authenticity is operationalized as honesty and expertise. A written survey is developed for 181 female Instagram users. The analyses of the data yields the following findings. First, honesty has a positive effect on fanship, relationship maintenance intention and purchase intention, while expertise affects fanship and relationship maintenance intention, but does not have a significant effect on purchase intention. Second, honesty and expertise have a positive effect on follower behavior intention through the partial mediation of fanship. Third, social attractiveness and physical attractiveness have a significant effect on fanship. However, all interaction effects between authenticity and attractiveness are not significant. Unlike authenticity, attractiveness has no direct effect on follower behavior intention. This study verifies the critical role of authenticity for an influencer in the context of SNS marketing and commerce, as this factor leads to followers behavioral intention as well as fanship in both direct and mediated paths.