• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.221-226
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• 1994

Almost preventive maintenance policies assumed that the system after pm has failure rate as before pm with probability p and as good as new with probability 1-p. This paper considers the s-expected cost of the model with imperfect periodic preventive maintenance that increasing minimal repair costs at failure and obtains the optimum periodic preventive maintenance time. Numerical example are shown in which the failure time of the system has gamma distribution.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.999-1007
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• 2009

This paper considers the optimal periodic preventive maintenance (PM) policy following the expiration of free-repair warranty. We assume that two periodic PM models with random maintenance quality which were proposed by Wu and Clements-Croome (2005) and Jung (2006b), respectively. Given the cost structure to the user during the cycle of the product, we derive the expressions for the expected cost rate per unit time. Also, we obtain the optimal PM number and the optimal PM period by minimizing the expected cost rate per unit time. The numerical examples are presented for illustrative purpose.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.5
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• pp.29-36
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• 2002

In the maintenance and retrofit planning of a bridge system, the optimal strategy for inspection and repair are suggested by minimizing the expected total life-cycle cost, which includes the initial cost, the costs of inspection, repair, and failure. Degradation of seismic performance is modeled by using a damage function. And failure probability is computed according to the degree of damage detection by random vibration theory and the event tree analysis. As an example to illustrate the proposed approach, a 10-span continuous bridge structure is used. The numerical results show that the optimum number of the inspection and the repair are increased, as the seismic intensity is increased and the soil condition of a site becomes more flexible.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.159-169
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• 2007

In this paper, a PMS(Pavement Management System) is presented for the public agency who wish to execute rational repair by referring to asset management information regarding road pavement. The aim of the paper is to provide the decision makers with the planning information regarding maintenance strategies for efficient road pavement management. We found that life cycle cost can be minimized and repair cost in each year fluctuates when repeating repair at the IRI management level. The validity of PMS application presented in this paper is investigated through case studies for conducted for 22 national highway road sections in Korea.

• Architectural research
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• v.14 no.2
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• pp.75-83
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• 2012

Buildings that are more than 10 years old generally have considerable repair and replacement costs due to the rapid deterioration of their systems. For public buildings in particular, which have national and social significance, considerable effort is required not only to ensure a long life cycle and safety but also to minimize the overall public expense. Along with increasing repair and replacement requirements, however, there have been problems related to the establishment of an accurate facility management budget. To address these concerns, a repair and replacement cost management system was constructed. This system manages both invested maintenance and forecast costs to establish a reasonable repair and replacement planning process and budget. The effectiveness of the system was verified through a pilot test targeting one of public Corporation (K).

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.43
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• pp.241-247
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• 1997

This paper is concerned with cost analysis model in free-replacement policy. The free-replacement policy with minimal repair is considered as follows; in a manufacturer's view point operating unit is periodically replaced, if a failure occurs between minimal repair and periodic maintenance time, unit is remained in a failure condition. Also unit undergoes minimal repair at failures in minimal-repair interval. Then total expected cost is calculated according to the parameter of failure distribution in a view of consumer's. The expected costs are included repair cost and usage cost: operating, fixed, minimal repair and loss cost. Numerical example is shown in which failure time of item has weibull distribution.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.638-644
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• 2012

In this study, we numerically estimated available and unavailable time of conventional railway by examining 60% which is known as average range of track utilization efficiency. We also estimated track repair time for maintenance which is the main factor of making track utilization change and analyzed appropriate estimated time. The railway's safety should be guaranteed by appropriate railway operating plan and by adequate rail facilities maintenance. At the same time, daily railway train 'Dia's recovery power should be reflected to the management plan. Considering these factors, we examined mechanical equipment and the national rail network in order to rationally estimate track repair time of the maintenance and to secure spare time in case of train delays. It was found that track utilization efficiency was more or less 60%.

• Magazine of the Korea Concrete Institute
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• v.3 no.4
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• pp.89-96
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• 1991

The maintenance techniques of reinforced concrete structures, which include diagnosis, repair and rehabilit¬ation, are not systematically establishtxL This study develops an expert system for maintenance of reinforced concrete structures based on the related documents and knowledge and experience of experts who work in these field. The analytical results using the developed expert system were compared to the real repair cases in field and they were generally satisfactory.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2215-2222
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• 2010

Advanced EMU have been enhanced in terms of safe transport and maintainability. It is a new urban railway technology that enables an operation institution to cut repair and maintenance costs and customers to use convenient service at lower costs based on IT technology. If a development vehicle of Advanced EMU is completed, it will be used to test the entire advanced EMU system through sufficient performance check and reliability check prior to operation in commercial line. It will also verify efficiency, safety, punctuality and energy efficiency of transport. Accordingly, it is necessary to figure how to repair and maintain vehicles to enhance safety of Advanced EMU system in cooperation with operation during the period of comprehensive evaluation on the operation of a development vehicle in a test line. In this paper, we investigated the maintenance program of Advanced EMU on test operation in Dabul line. The test condition and operation environment of Advanced EMU in Daebul line was analyzed.

• The Journal of the Korean dental association
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• v.54 no.12
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• pp.996-1023
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• 2016

There are many kinds of maintenance care services for removable denture patient. Adjustment of the denture base and occlusion should be performed regularly not only for pain relief but also for maintaining the denture function. Direct and indirect relining are needed frequently in specific cases including mandibular distal extension case or non-symmetric residual teeth situation. Surface treatments for metal and resin are essential in the relining procedure. Clinical process for the denture repair is similar to indirect relining which needs inter-occlusal registration. Especially, the peridontal maintenance care and caries prevention are most important way to preserve the abutment teeth in partial edentulism. Moreover, the caring method for the denture and the tissue should be instructed to the denture patient.