• Journal of the Korean housing association
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• v.12 no.3
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• pp.75-83
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• 2001

The deteriorted high-rise apartments make a social problem in now days. As a result, and new alternative plan for deteriorted high-rise apartments such as the remodeling concept must be considered. This study aims to develop the remodeling items which is the guide lines when remodeling of the apartment will be conducted. Thorough the case studies of maintenance and repair status of the deteriorted apartments in seoul, reasonable guidelines for selection of remodeling items were developed. Physical maintenance items includes those that need major repair activity like wall painting, water proof roof, change/repairs/implement of heating system, boiler, city gas pipelines, cold and hot water pipes, elevators, cleaning of water tanks. The period of repair is shorter than the durable year of law or codes. As a result of the study, basic maintenance items and actual repair period were proposed. This result will be the basic guidelines for remodeling items.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.606-607
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• 2015

The traffic volume on the road shows various trends reflecting regional characteristics for monthly and hourly, and economic loss affecting users varies according to the selected period for the maintenance of road pavements. Therefore, in this study, the user cost (or delay cost) for monthly and hourly on the work zone near the Maesang Bridge Section on Poseung-Gu, Pyeongtaek-si, Gyeonggi-do was calculated using the time series models and VISSIM, and based on the result, the effect of user cost reduction according to the selection of best maintenance period was examined. The analysis result showed that the month of the lowest user cost occurred due to the maintenance of target section was January (10,293,258 KRW/Day×1km) and the month of the greatest user cost occurred was November (13,337,495 KRW/Day×1km).

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.158-166
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• 2007

After constructing the high-speed railroad, KORAIL acquired advanced maintenance techniques about Rolling-stocks. Also RCM theory is applied to maintenance field like as inspection period and method. In the meantime, the development of the maintenance methode for Rolling-stock is slow when it compares to the components and system technology. For this reason KORAIL tries to build the optimal maintenance system which can lead the Rolling-stock maintenance technique. The existing vehicle except High Speed train KTX are separated to electric motor car, electric locomotive, diesel locomotive, diesel car, passenger car and freight car. The inspection period and methode for existing vehicles which mentioned above will be examined and the optimal Rolling-stock maintenance technique will be applied.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.23 no.2
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• pp.150-153
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• 1978

A study was conducted to determine the critical period of weed-free maintenance required to produce maximum soybean yields. Leaf area index(LAI). crop growth rate (CGR), and number of pods per plant were increased with extended weed-free maintenance period. Consequently, maximum soybean yields were obtained when weeds were controlled for more than six weeks, but a relatively high level of ;soybean production was attained with only two weeks of weed free maintenance.

• Journal of the Korea Society of Computer and Information
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• v.22 no.12
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• pp.145-153
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• 2017

Systemic management is required at each phase of the C4I system life cycle to achieve information advantage in the battlefield through stable operation of the C4I system under the NCOE. In particular, the maintenance phase is the longest period of the C4I system life cycle, and it is easy to utilize and analyze data such as faults that occur during system operation. However, according to the previous research, the maintenance is evaluated as a phase in which the definition and management of comprehensive indicators are insufficient compared to other phase. In this paper, we propose the method of C4I Maintenance Priority decision using Maintenance metric. As a result of modifying the Naval Tactical C4I System's preventive maintenance cycle according to the priority, the total number of faults is reduced and the maintenance efficiency is improved.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.618-619
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• 2015

The costs due to the maintenance and its method of national road have increased every year, and the maintenance costs have become higher due to the maintenance method without considering the characteristics of each region. This study is a preliminary study regarding the determination of maintenance method according to the characteristics of each region by applying variables (e.g. serviced time, traffic volume, average temperature, maximum temperature, minimum temperature, rainfall, and snowfall) to decide the maintenance and its method through the correlation analysis of road maintenance and repair period for each regional agency using the maintenance history data of national road management agency.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.84-86
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• 2005

The digital systems such as PLC or DCS have been applied to non-safety systems of nuclear power plants because of many difficulties in using analog systems. Nowadays, digital systems have been applied to safety systems of the plants such as reactor protection system. One of the main advantages of digital systems is applicability of automatic testing methods to the systems. The protection system requires high-reliability and high-availability because it shall minimize the propagation of abnormal or accident conditions of nuclear power plants. The calculation of reliability and availability of systems depends on the maintenance period of the system. In general, the maintenance period of the protection system is one-month in case of the manual test. However, the cycle of test can be shortened in several hours by using automatic periodic testing. The reliability and availability of the system is better when test period is shortened because the reliability and availability is inverse proportion to the test period. In this research, we developed the automatic periodic testing method for KNICS Reactor Protection System, which can test the system automatically without an operator or a tester. The automatic testing contained all functions of reaction protection systems from analog-to-digital conversion function of the bistable Processor to the coincident trip function of the coincident processor. By applying the automatic periodic testing to reaction system, the maintenance cost can be cut down and the reliability can be increased.

• Journal of the Korean Operations Research and Management Science Society
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• v.3 no.2
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• pp.91-93
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• 1978

A methodology which can be employed to obtain an optimal preventive maintenance policy that maximizes the total machine running time over the specified working period is proposed. A system considered is comprised of m machines and r

• International Journal of Reliability and Applications
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• v.12 no.1
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• pp.41-48
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• 2011

This paper considers the maintenance model suggested by Jung and Park (2010) to adopt the Bayesian approach and obtain an optimal replacement policy following the expiration of NFRRW. As the criteria to determine the optimal maintenance period, we use the expected cost during the life cycle of the system. When the failure times are assumed to follow a Weibull distribution with unknown parameters, we propose an optimal maintenance policy based on the Bayesian approach. Also, we describe the revision of uncertainty about parameters in the light of data observed. Some numerical examples are presented for illustrative purpose.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.15 no.26
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• pp.173-179
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• 1992

This paper is concerned with preventive maintenance model for the items whose failures are dependent on their wear level. The previous maintenance models have used time as their decision variable, but it is not appropriate for the case which have wear dependent processes for their failures. In this paper, we consider an operating item which is under periodic review and which is subject to degradation. The scheduled maintenance (overhaul ) is based on the level of item degradation rather time. A functional equation for the total expected cost over an infinite horizon period is formulated and solved.