• 산업경영시스템학회지
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• 제18권34호
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.1655-1660
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• 2009

At the Rolling-stock, most important thing is thorough maintenance for safety as a mass transit. Recently, many studies of cost down method and acquisition of high reliability have being progressed with considering of safety. Maintenance cost is closely relative to the preventive maintenance. But generally the preventive maintenance is decided in compliance with an experience. So the study of cost down method at the preventive maintenance is difficult. In this study, many results of effectiveness and optimization for the preventive maintenance are checked. Then., it is possible that efficiency preventive maintenance method will be able to suggest.

• 대한안전경영과학회지
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• 제19권3호
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• pp.89-95
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• 2017

This paper presents another maintenance policy for a group of units under finite operating horizon. A group of identical units are subject to random failures. Group maintenances are performed to all units together at specified intervals, and the failed units during operation are remained idle until the next group maintenance set-up. Unlike the traditional assumption of infinite operating horizon, we adopt the assumption of the finite operating horizon which reflect the rapid industrial advance and short life cycle of modern times. The units are under operation until the end of the operating horizon. Further, the operation of units are extended to the first group maintenance time after the end of the horizon. The total cost under the proposed maintenance policy is derived. The optimal group maintenance interval and the expected number of group maintenances during the horizon are found. It is shown that the proposed policy is better than the classical group maintenance policy in terms of total cost over the operating horizon. Numerical examples are presented for illustrations.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.72-73
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• 2019

As the physical functions of school buildings and the changes in the functions of educational facilities due to social change are increasing, the demand for fundamental and long-term measures for the maintenance of educational facilities is expanding. However, depending on the function of the facility, the maintenance work has been carried out only when it is directly related to the safety problem, or when the request of the school facility manager is requested, rather than supporting preventive maintenance. In this study, we investigate the maintenance process of educational facilities and propose a method to manage the maintenance process of the educational facilities in the unit of space for establishing an efficient maintenance management system.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.251-252
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• 2015

Enough school facility maintenance data should be accumulated in a database or data warehouse in order to supply information about school facility correct maintenance budget plan, budget assignment, and cycle and rate of maintenance or replacement. For those, this research analyze the present school facility maintenance practice and budget and construction cost structure. In order to solve the problems, this study analyze the present practice of maintenance and replacement and obtain LCC(Life cycle cost) data, perform expert interview and then establish construction work breakdown structure of maintenance of educational facility by combining work breakdown structure(WBS) and cost breakdown structure(CBS).

• 한국신뢰성학회지:신뢰성응용연구
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• 제11권3호
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• pp.305-318
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• 2011

In the statement of logistics reliability prediction methodology, all components should be managed as the analysis objectives. However, in some reliability prediction of weapon systems, fastening parts, e.g., screws, bolts and nuts, have been frequently ignored because some organizations related to weapon systems have emphasized that those parts are not significant in their failures rate and functions. In this paper, failure rates, modes, and distributions were presented to prove that fastening parts should be included in reliability prediction objectives. Also, failure rate prediction methods of fastening parts are presented and compared.

• 산업공학
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• 제16권1호
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• pp.27-33
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• 2003

The maintenance cost in K Steelworks has been continuously increased in proportion to the production cost. However, there seems to be a possibility of reducing cost through the optimization of maintenance actions. The failure types of the equipment in steelworks ate various with different failure cost. Thus the failure rate and cost of each type of failures should be considered simultaneously when the optimum maintenance period is to be determined. It is considered that the equipment undergoes periodic replacement and a specified number of incomplete preventive maintenance actions are performed during a replacement period. Assuming that the time to failure follows a Weibull distribution, the parameters of the failure rate are estimated using the maximum likelihood estimation. The optimal replacement period is determined to minimize the average cost per unit time. As the result of analysis it is suggested that the existing maintenance period for a hot-rolling equipment can be extended significantly.

• 한국구조물진단유지관리공학회 논문집
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• 제5권4호
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• pp.161-167
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• 2001

By means of analyzing the problems in monitoring plan, design, installation, operation based on maintenance monitoring system installed in subway tunnel section, the improved methods of were proposed for applying to subway monitoring maintenance effectively in the future. The choice of the better monitoring system, the operating method of monitoring system, the confidence and continuity of maintenance monitoring, the performance of responsible monitoring supervision in the phase of the planning of monitoring and design were proposed. The problem and developed plan in the different monitoring systems, the calibration and correction of monitoring system, the analysis for the results and plan for maintenance in the phase of installation of monitoring system and operation were also proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.742-743
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• 2007

A maintenance plan of power system equipment reduces failure rate caused by equipment's age. To prevent unexpected failure, the maintenance is performed periodically according to the interval time. The more expansive equipment's scale is, the more the maintenance without considering costs sustains a economical loss. Hence, the maintenance's time and the cost must be considered when maintenance which is considering the reliability is implemented. In this paper, optimum maintenance interval is calculated by considering minimum maintenance cost of the equipment with the combined cycle units in Korea power systems.

• 한국신뢰성학회지:신뢰성응용연구
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• 제18권2호
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• pp.184-191
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• 2018

Purpose: The purpose of this study is to propose a method to calculate the optimal preventive maintenance cycle of radar used in the aviation weapon system of ROKAF. Methods: A hybrid model is used to estimate the optimal preventive maintenance cycle in a system that can perform condition based predictive maintenance (CBPM) through continuous diagnosis. The failure data of the radars operating in the military were used to calculate the reliability. Results: According to the research results, the reliability threshold of the radar began to decrease after 5 flights, and decreased rapidly after 12 flights. Since the second check, costs have continued to decline. Conclusion: A method is proposed to determine the cycle of optimal preventive maintenance of radar within operational budget through modeling results between reliability limit and cost for radar. The results can be used to determine the optimal preventive maintenance cycle and frequency of various avionics equipment.