• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.11a
• /
• pp.236-236
• /
• 2009

This paper demonstrates the application of the preventive maintenance, process to analyse and develop preventive maintenance tasks for rectifier and electric transformer in the SeoulMetro company. Attention is given to the frequency designation, technical details regarding the radiometer, previous electromagnetic noise measurements, and applications of the noise data. This study confirms the feasibility and effectiveness of preventive maintenance applications in the electric trains.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.47-58
• /
• 1998

This study is to try grading size and economic values in irrigation reservoirs for the purpose to maintenance management valuation technique. This use main irrigation reservoirs which are managed by Farmland Improvement Associations(FIA) to estimate grading of irrigation reservoirs for maintenance and management. In order to make efficient management on irrigation reservoirs, this study will be a basic data at a decision ranking of investment which are followed by conservation and maintenance management.

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

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.8
• /
• pp.1177-1183
• /
• 2013

In this paper, the analysis of inspection period bases on reliability is suggested in the field of traction power system. Even though there are several maintenance models, the most commonly used maintenance assessment has been focused on time based maintenance in real traction power systems. The maintenance intervals are selected on the basis of long-time experience. It ensures high availability and exact planning of staff. Reliability centered maintenance, which evaluates criticality and severity of each failure mode, achieves the operation, maintenance, and cost-effective improvement that will manage the risks of equipment. This paper deals with electrification in railway inspection frequency and applied reliability based inspection frequency instead of constant intervals. The distribution function of failure rate in traction power system belongs to Weibull function. Also, the fault data and the number of installed equipments for electrifications are collected. The failure history is investigated and classified in detail. Though these complicated procedures, it contribute to extend equipment lifetime and to reduce maintenance costs.

• Journal of Advanced Marine Engineering and Technology
• /
• v.23 no.6
• /
• pp.785-793
• /
• 1999

There are two kinds of method in ship maintenance. One is the corrective maintenance and the other is the preventive maintenance. For these maintenances recently the stochastic techniques are widely used to keep the maximum availibility and the optimal maintenance period minimizing a given cost function. Thus this paper suggest a method to decide the optimal policy of ship's maintenances by using dynamic programming and the effectiveness of the method is verified through several examples in which failure rates and maintenance data of ship's machineries and parts are given.

• Proceedings of the KSR Conference
• /
• 2007.11a
• /
• pp.784-791
• /
• 2007

Most operational organization and railway authority which conduct scheduled maintenance(SM) have carried out the preventive maintenance(PM) based on the information provided from supplier and manufacturer of railway system. However these activities are far away from reality and low the efficiency, it is because an appropriate methods for system selection didn't take into account for improving maintenance efficiency. Therefore, the current SM tasks and maintenance activities lead to lots of spend on the cost and time. To solve the above problem, this thesis presents new approach methodology. This proposes the criteria for reliability centered maintenance(RCM) system selection through level of quantification of each parameter, i.e, frequency, severity and maintenance cost, etc. To do this, the field operation data and information of maintenance cost are essential. As applying this methodology, we can look forward to improving efficiency of PM/SM, and reducing cost.

• Journal of Information Technology Applications and Management
• /
• v.11 no.3
• /
• pp.77-87
• /
• 2004

The importance of information systems(IS) operations and maintenance is increasing as the costs of IS operations and maintenance take larger share of total IS costs and organization's dependency on IS is increasing. However, this area has received relatively little attention from scholars and practitioners despite of its significance. The main objectives of this study are to provide practical guidelines for improving IS operations and maintenance practices, and to propose a research framework for this area. To accomplish this objectives, the following three issues are investigated. First, IS operations and maintenance practices of a case company are analyzed. Second, the current practices are compared with best practices. Finally, suggestions are made based on the analyses to improve the IS operations and maintenance practices.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.2
• /
• pp.248-253
• /
• 2007

Traditional time based preventive maintenance is used to constant maintenance interval for equipment life. In order to consider economic aspect for time based preventive maintenance, preventive maintenance is scheduled by RCM(Reliability-Centered Maintenance) evaluation. So, Markov state model is utilized considering stochastic state in RCM. In this paper, a Markov state model which can be used for scheduling and optimization of maintenance is presented. The deterioration process of system condition is modeled by a Markov model. In case study, simulation results about RCM are used to the real historical data of combustion turbine generating units in Korean power systems.

• Journal of the Korea Society of Computer and Information
• /
• v.20 no.12
• /
• pp.175-180
• /
• 2015

It is important to maintain information system (IS) following the business and institutional change. Even if successfully developed information systems, we cannot gain the benefit from the systems without the proactive maintenance activities. However, the importance of IS maintenance has not been considered as much as the system development, and we don't have any specific performance management structure. The objective of this study is to identify the relationship between IS maintenance activities and utilization. For empirical test of the hypothesis model, the sample data is collected from public information system sites. Results from multiple regression analysis reveal that proactive maintenance activities including IS maintenance cost increase, improving functionality, and enhancing ease of use have a causal effect on the IS utilization.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.1191-1197
• /
• 2009

KTX decelerator is a device to fulfil a role of transmission of turning force to reduction device of an axle by serrate device. Currently, KTX decelerator's TBO(Time Between Overhaul) has 3 years cycle. As for the dissembly maintenance of a device, its maintenance is conducted every 1.4M kms. In this study, since opening of KTX, we analyzed reliability, maintainability, availability of KTX decelerator by researching historical records of maintenance of the decelerator, and based on above data, investigated whether its TBO cycle and maintenance works properly or not And we considered maintenance policies of KTX decelerator to improve efficiency in maintenance in the future.