• Journal of Energy Engineering
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• v.24 no.1
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• pp.10-16
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• 2015

Recently, RCM(reliability centered maintenance) process is introduced and applied for the planning and implementing efficient and effective maintenance system in terms of optimal rolling stock maintenance. Particularly, cost-time benefits analysis associated with the implementation of RCM for rolling stock maintenance is necessary and required for railway operator in advance. The RCM process was primarily starting from military, airplane and nuclear industries and is now adapted in railway industry for local railway operators. This paper focuses on suggesting the way of connecting the RCM process with railway maintenance activities in the railway operation field. Thus, in order to introduce and establish reliability activities, it needs to review and evaluate the maintenance environment in the organizational point of view. Based on these reviews and evaluations, various maintenance methodologies are reviewed for customizing local railway field situations and establish specific process in the application of major systems on the reliability technology. In this paper, the railway RCM process is proposed for the establishment and construction of the systematic and optimal maintenance system.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.313-322
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• 2016

Purpose: We introduce ways to employ Markov chain model to evaluate the effect of preventive maintenance process. While the preventive maintenance process decreases the failure rate of each subsystems, it increases the downtime of the system because the system can not work during the maintenance process. The goal of this paper is to introduce ways to analyze this trade-off. Methods: Markov chain models are employed. We derive the availability of the system consisting of N repairable subsystems by the methods under various maintenance policies. Results: To validate our methods, we apply our models to the real maintenance data reports of military truck. The error between the model and the data was about 1%. Conclusion: The models developed in this paper fit real data well. These techniques can be applied to calculate the availability under various preventive maintenance policies.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.363-366
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• 2004

KAERI is developing the Advanced Spent Fuel Conditioning Process (ACP) as a pre-disposal treatment process for spent fuel. In this process, the management process must operate in intense radiation fields as well as in a high temperature. Therefore, remote maintenance has played a significant role in this process. Hence suitable remote handling and maintenance technology needs to be developed along with the design of the process concepts. To do this, we developed the digital mockup for the ACP. The digital mockup provides the capability of verifying the remote operability of the process without fabrication of the process equipment. In other words, by applying virtual reality to the remote maintenance operation, a remote operation task can be simulated in the digital mockup. Through utilizing this graphic simulation in this digital mockup, general guidelines can be established for designing equipment intended for remote handling and maintenance. Also, the designer of the equipment that must be remotely maintained should ensure that there is adequate access to the process equipment. The graphic simulator will substantially reduce the cost of the develo363pment of the remote handling and maintenance procedure as well as the process equipment.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.191-201
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• 2016

A stochastic process has been used to develop a condition-based model for preventive maintenance of armor units of rubble-mound breakwaters that can make a decision the optimal interval at which some repair actions should be performed under the perfect maintenance. The proposed cost model in this paper based on renewal reward process can take account of the interest rate, also consider the unplanned maintenance cost which has been treated like a constant in the previous studies to be a time-dependent random variable. A function for the unplanned maintenance cost has been mathematically proposed so that the cumulative damage, serviceability limit and importance of structure can be taken into account, by which a age-based maintenance can be extended to a condition-based maintenance straightforwardly. The coefficients involved in the function can also be properly estimated using a method expressed in this paper. Two stochastic processes, Wiener process and gamma process have been applied to armor stones of rubble-mound breakwaters. By evaluating the expected total cost rate as a function of time for various serviceability limits, interest rates and importances of structure, the optimal period of preventive maintenance can easily determined through the minimization of the expected total cost rate. For a fixed serviceability limit, it shows that the optimal period has been delayed while the interest rate increases, so that the expected total cost rate has become lower. In addition, the gamma process tends to estimate the optimal period more conservatively than the Wiener process. Finally, it is found that the more crucial the level of importance of structure becomes, the more often preventive maintenances should be carried out.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.168-169
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• 2021

Maintenance is carried out over a long period of time, and various documents are utilized in the maintenance work. In maintenance work which is progressed simultaneously in a short period of time, it is important to provide relevant information to the parties in a timely manner. As the types of work increase, manager needs more time and effort to select and utilize the documents. It is necessary to have an information system that supports the person in charge by grasping work procedures for each construction and providing the necessary documents and information for that step. This paper proposes an process based nexus model that can provide necessary documents to the parties to the work steps by linking the maintenance work process and BIM. Through the nexus model presented, manager can efficiently acquire the necessary documents and utilize them for the construction works currently being carried out.

• Journal of the Korean housing association
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• v.21 no.3
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• pp.115-124
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• 2010

The environment which has been destroyed for the national growth since 1960's would seem to offer infinite resources to human, but now, the existence of human being is threatened by the development thoughtless for the environment. The World Powers have concentrated on green growth with eco-friendly resource since the end of 20th century. Korea suggested that the vision was the low carbon for green growth in 2008. It is necessary to supply Long-Life Housing in the green technology in terms of the sustainable housing development based on various life style, life cycle of the residences, the restrain remodeling and redevelopment in construction. This study is aim to establish the development of maintenance process to make continuous inhabitation of Long-Life Housing that has the separated SI for maintenance, durability, variability and remodeling. The maintenance for Long-Life Housing is very important to have more than 50~70 years the long term of life cycle in comparison with Housing. Also, the roles of manager and user are important parts in Long-Life Housing. The present maintenance for Housing is shift and repair works by the routine maintenance and demage. However, The maintenance for Long-Life Housing should consider movement and flexibility. In addition, Long-Life Housing requires the proper process of maintenance because it is different from Housing in housing concept, design and constructions stage. Therefore this study shows the efficient maintenance process for Long-Life Housing.

• Journal of the Korea Safety Management & Science
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• v.9 no.3
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• pp.15-19
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• 2007

This paper proposes a maintenance method to integrate worker's safety concerns into the process activities of the manufacturing system and it is to be considered as a part of the scope of maintenance engineering. The proposed method incorporates worker's health and safety considerations into maintenance engineering in each of the manufacturing process using reliability analysis. It can help to make a better planning and implementation of maintenance activities for the manufacturing system.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1354-1358
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• 2003

The process equipment for handling high level radioactive materials like spent fuels is operated in a hot cell, due to high radioactivity. Thus, this equipment should be maintained and repaired optimally by a remotely operated manipulator. The master-slave manipulators(MSM) are widely used as a remote handling device in the hot cell. The equipment in the hot cell should be optimally placed within the workspace of the wall-mounted slave manipulator for the maintenance operation. But, because of the complexity in the hot cell, there would be some parts of the equipment that are not reached by the MSM. In this study, the maintenance process for these parts of the equipment is developed using virtual prototyping technology. To analyze the workspace of the maintenance device in the hot cell and to develop the maintenance processes for the process equipment, the virtual mock-up of the hot cell for the spent fuel handling process is implemented using IGRIP. For the implementation of the virtual mock-up, the parts of the equipment and maintenance devices such as the MSM and servo manipulator are modeled and assembled in 3-D graphics, and the appropriate kinematics are assigned. Also, the virtual workcell of the spent fuel management process is implemented in the graphical environment, which is the same as the real environment. Using this mock-up, the workspace of the manipulators in the hot cell and the operator's view through the wall-mounted lead glass are analyzed. Also, for the dedicated maintenance operation, the analyses for the detailed area of the end effectors in accordance with the slave manipulator's position and orientation are carried out. The parts of the equipment that are located outside of the MSM's workspace are specified and the maintenance process of the parts using the servo manipulator that is mounted in the hot cell is proposed. To monitor the process in the hot cell remotely, the virtual display system by a virtual camera in the virtual work cell is also proposed. And the graphic simulation using a virtual mock-up is performed to verify the proposed maintenance process. The maintenance process proposed in this study can be effectively used in the real hot cell operation and the implemented virtual mock-up can be used for analyzing the various hot cell operations and enhancing the reliability and safety of the spent fuel management.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.183-188
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• 2011

Management of maintenance parts in the aircraft have difficulty because of high cost of part, necessity of separate managements, and very many kinds of parts. The serial number of parts was used in maintenance process and then the results was depended on worker's ability. Also the workers used printed work order and manual at every time in maintenance processes. In this study, we analyzed the maintenance process and the information that occurs in the material warehouse and hangar for large airline company to solve the problems about inventory and visualization. Based on above analysis we developed the maintenance process with integrated by information technologies such as QR code and tablet PC. We expect the reduced errors resulting from visually checking and decreased work hours and maintenance cost and will finally develop the smart work.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2059-2063
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• 2004

Most power plants have operated many independent computerize systems for maintenance. Independence of systems have caused complexity of business process and inconvenience of computer system management. Because the equipment and material master data is not standardize and structurize, it is difficult to manage equipment maintenance history and material delivery. Especially equipment classification criterion is important for standardization of every maintenance information. It is necessary to integrate function of independent systems for business process simplification and rapid work flow. this paper provides equipment classification criterion design and system integration method with the case of live system development.