• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1627-1633
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• 2004

Safety and punctuality in the subway are considered as critical factors. This system is composed of many factors like signals, rails, electrical power sources, rolling stocks. The effective inspection should be carried out at all the times for the safety and punctuality. Purpose of the rolling stocks maintenance is to offer the optimum condition of vehicles, and minimize the maintenance expenses. This paper suggests appropriate maintenance period of rolling stocks to enhance the utility efficiency in SMSC.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.587-596
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• 2008

This paper develops the optimal periodic preventive maintenance policies following the expiration of warranty: renewing warranty and non-renewing warranty. After the warranty period is expired, the system undergoes the PM periodically and is minimally repaired at each failure between two successive PMs. Firstly, we determine the expected cost rate per unit time and the expected downtime per unit time for the periodic PM model. Then the overall value function suggested by Jiang and Ji(2002) is applied to obtain the optimal PM period and the optimal PM number. Finally, the numerical examples are presented for illustrative purpose.

• Journal of the Korea Safety Management & Science
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• v.2 no.4
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• pp.1-8
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• 2000

Equipment and machine of industrial plant are give effect to mechanical-stress of many working-stop or long time operating. Therefore, to be old and decrepit of every king of equipment. As long time operating equipment period into increase conservation and of repair equipment time is efficacious necessity of utility factor gradually that of productivity of diminution and complete equipment expense of increase. Conservation at special skill working and necessity is that will effectually and complete a period prevention management diagnosis can conservation point at issues at in advance.

• The Journal of Sustainable Design and Educational Environment Research
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• v.13 no.2
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• pp.13-25
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• 2014

The recent trend has been consistently raised by the media of educational environment issues such as deteriorated existing school facilities, water-leaks due to the lack of proper maintenance and poor toilet facilities. For the efficient use of the budget to be used for maintenance of school facilities, an effort to extend the life of the facility to the max is needed. However, current maintenance system of school facilities is to deal with the defects after discovered, and consequently the durable period is shortened due to early deterioration of facilities and efficient budget execution cannot be realized. For this reason, the result emphasizes the need to improve maintenance management system of school facilities, and proposes a systematic bill of school facilities maintenance according to expert investigation and correlation analysis through school facilities maintenance-related information that is distributed to a number of laws.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.113-122
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• 2008

In this paper, we consider a periodic preventive maintenance policy in which each preventive maintenance reduces the hazard rate of amount proportional to the failure intensity, which increases since the system started to operate. And the effect of preventive maintenance at each preventive maintenance epoch is different. The expected cost rate per unit time for the proposed model is obtained. We discuss the optimal number N of the periodic preventive maintenance and the optimal period x, which minimize the expected cost rate per unit time and obtain the optimal preventive maintenance schedule for given cost structures of the model. A numerical example is given for the purpose of illustrating our results when the failure time distribution is Weibull distribution.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.139-146
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• 1995

This study is concerned with cost analysis in periodic maintenance policy. Generally periodic maintenance policy in which item is repaired periodic interval times. And in the article minimal repair is considered. Minimal repair means that if a unit fails, unit is instantaneously restored to same hazard rate curve as before failure. In the paper periodic maintenance policy with minimal repair is as follows; Operating unit is periodically replaced in periodic maintenance time, if a failure occurs between minimal repair and periodic maintenance time, unit is replaced by a spate until the periodic time comes. Also unit undergoes minimal repair at failures in minimal-repair-for-failure interval. Then total expected cost per unit time is calculated according to maintenance period and scale parameter of failure distribution. Total cost factors ate included operating, fixed, minimal repair, periodic maintenance and replacement cost Numerical example is shown in which failure time of system has erlang distribution.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.37-43
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• 2014

Nuclear power plants(NPPs) are consisted of power production functions and safety functions preventing leakage of radiation. Operators working in NPPs shall maintain these functions during an operation period through various activities such as improvement & modification, corrective maintenance, preventive maintenance and surveillance test. According to the performance of these work activities, there are configuration changes in NPPs systems. Its changes cause the increase of safety risks(CDF) and plant trip risks. Recently, the importance of risk management is increasing gradually in the operation process of NPPs. Therefore, this paper presents the work management methods using the various risk monitoring systems during power operation and overhaul period. Also this paper suggests the optimum application ways of risk systems for work management.

• Architectural research
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• v.14 no.1
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• pp.35-44
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• 2012

Build-Transfer-Lease (BTL) was introduced to the domestic construction market in 2005. Now, seven years later, the BTL model is most active for educational facilities. In 2011, 93 educational facility projects entered the maintenance stage. Considering the characteristics of today's BTL projects for educational facilities, the main issues are the initial performance and maintenance of educational facilities and the service-providing status for the 20-year operational management period, in relation to providing safety and convenience to students, the facility users. Seeking a solution, local education offices and departments in charge of BTL under the Ministry of Education, Science, and Technology have been exploring various methods of evaluating operational maintenance performance from various perspectives. For educational facility BTL projects, however, the appropriateness of initial operation performance evaluation, rather than considering the 20-year operational management period, is controversial in regards to sustainability. On this account, performance evaluation items in four areas-operational maintenance evaluation, facility performance status evaluation, maintenance subject evaluation, and sustainable change response evaluation-should be extracted. An indicator of facility performance evaluation is presented in this study through an AHP survey targeting experts, as part of establishing an operation performance evaluation system for educational facility BTL projects.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.548-551
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• 2004

In suite of a high supply of multi-family housings, the government's housing policies have only been focusing on the construction of housings and their supply, while being almost indifferent to the maintenance management of them. As a result, a considerable amount of inconvenience to the use of housing resources and habitation of residents occurred. Accordingly, on this paper, the current housing policies and their inspections on the maintenance period are compared and analyzed with suggestions for improvement. Analysis shows that repairing of housings at appropriate time not only significantly delays the deterioration of housings, but also keeps the function of housings to their original condition. Therefore, through an efficient management of repair maintenance, wearing of buildings can be delayed and their functions can be improved.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.3
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• pp.41-52
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• 2020

This paper investigates the stress-reducing preventive maintenance model through numerical experiments. The preventive maintenance model is used to analyze the relationship between related conditions and variables to gain insight into the efficient operation of the system when performing preventive maintenance in real-world situations. Various preventive maintenance models have been developed over the past decades and their complexity has increased in recent years. Increasing complexity is essential to reflect reality, but recent models can only be interpreted through numerical experiments. The stress-reducing preventive maintenance is a newly introduced preventive maintenance concept and can only be interpreted numerically due to its complexity, and has received little attention because the concept is unfamiliar. Therefore, for information purposes, this paper investigates the characteristics of the stress-reducing preventive maintenance and the relationship between parameters and variables through numerical experiments. In particular, this paper is focusing on the economic feasibility of stress-reducing preventive maintenance by observing changes in the optimal preventive maintenance period in response to changes in environmental stress and the improvement factor. As a result, when either the environmental stress or the improve effect of stress-reducing preventive maintenance is low, it is not necessary to carry out the stress-reducing preventive maintenance at excessive cost. In addition, it was found that the age reduction model is more economical than the failure rate reduction model.