• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4509-4514
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• 2010

In this thesis, the effect of switch maintenance improvement is confirmed after testing and operating the switch monitoring system that were researched and developed originally in order to improve method of electric switch maintenance. However, as in an automatic interlocking station where a ground crew was not placed, repair and inspection could not be carried out until the maintenance person comes in case of switch problems or maintenance. In order to improve this issue, control module was installed in a monitoring system which can communicate through a data radio to a remote computer. Thus, the monitoring device can receive control information which a remote computer commands during the operation of switches. Afterward, it shows information on the real-time status of swith, in particular, anomaly situation through user interface after the switch is operated. By improving performance of the monitoring system in this way which can be managed and controled at a remote place, the prompt countermeasure system in case of disruption will be built and as a result, efficiency and convenience of maintenance improvement will be expected to increase.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.1
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• pp.25-32
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• 2012

Korea Hydro & Nuclear Power Co. (KHNP) has developed and implemented the maintenance effectiveness monitoring (MR) programs for the operating nuclear power plants. The MR program is developed by reflecting design characteristics of the operating nuclear power plants to monitor the plant performance for improving the safety and reliability. Recently, KHNP has built a new nuclear power plant, and developed the MR program to establish the advanced maintenance system by reflecting unique design characteristics based on the OPR1000 standard model. So, the MR program developed in this study has another characteristics in comparison with the OPR1000 standard model, and we will verify the suitability of the MR program through evaluating initial performance of the plant. The safety and reliability of the new plant will be improved by developing and implementing the MR program.

• Structural Monitoring and Maintenance
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• v.3 no.3
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• pp.233-257
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• 2016

This paper provides an overview on development of long-span bridges monitoring in Japan, with emphasis on monitoring strategies, types of monitoring system, and effective utilization of monitoring data. Because of severe environment condition such as high seismic activity and strong wind, bridge monitoring systems in Japan historically put more emphasis on structural evaluation against extreme events. Monitoring data were used to verify design assumptions, update specifications, and facilitate the efficacy of vibration control system. These were among the first objectives of instrumentation of long-span bridges in a framework of monitoring system in Japan. Later, monitoring systems were also utilized to evaluate structural performance under various environment and loading conditions, and to detect the possible structural deterioration over the age of structures. Monitoring systems are also employed as the basis of investigation and decision making for structural repair and/or retrofit when required. More recent interest has been to further extend application of monitoring to facilitate operation and maintenance, through rationalization of risk and asset management by utilizing monitoring data. The paper describes strategies and several examples of monitoring system and lessons learned from structural monitoring of long-span bridges in Japan.

• Journal of Environmental Impact Assessment
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• v.28 no.3
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• pp.263-274
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• 2019

The purpose of this study is to examine a monitoring method, management zones, and maintenance strategies for water friendly facilities in urban streams after the completion of ecological restoration projects. Maintenance monitoring items are composed of 'use space& facilities', 'trails& bike roads', 'access', and 'boards'. The evaluation standards of water friendly facilities are 'maintenance conditions', 'safety', and 'usage level' which are rated as 'good', 'moderate', and 'poor'. Through a field survey and evaluation of 15 stream sections in Jeonjucheon,the management levels of each water friendly facility are determined as 'priority maintenance', 'general maintenance', 'maintain/remove', and 'remove'. Based on the evaluation results, management zones and maintenance strategies are proposed for each stream section. As a results, the stream sections of J2, J3, J4, and J9 which have 5 to 9 facilities with 'priority maintenance' are determined as 'intensive management zone'. The stream sections of J5, J6, J7, J8, J11, and J14 which have 1 to 3 facilities with 'priority maintenance' are determined as 'regular management zone'. The stream sections of J1, J10, J12, J13, and J15 which have no facilities with 'priority maintenance' are determined as 'minimum management zone'. The process of monitoring & evaluation system and determining management zones can be applied to establish a systematic maintenance plan for water friendly facilities by participation of governance in the future.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.473-484
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• 2016

This study aims to establish a monitoring method for managing the effective maintenance of tailings dams. The monitoring of a tailings dump area involves several parameters and their investigation through a selection of evaluation items. The extents of defects and progressive failures also need to be effectively estimated. Therefore, the monitoring items can be subdivided into categories relating to the retaining wall structure (concrete wall, reinforcing stone wall, mesh gabions) and general facilities (liner, covering soil, slope, tailings, rain protection facility, leachate, planting), and quantitative evaluations can then be conducted for each condition. In doing so, we developed a systematic monitoring method that assesses the dam maintenance condition with grades and scores. The field application of the monitoring method results showed it to provide a more detailed evaluation than existing monitoring methods: the method detected an additional 16 defects missed by conventional methods. The evaluation gave scores of 89.3, 22.2, and 27.8 to the Geumjang mine tailings dam, the Gupoong mine tailings dam, and the Hwachun mine tailings dam, respectively. The advanced method can provide quantitative evaluation and perform detailed monitoring of the dams. This quantitative evaluation can be used to decide on maintenance priorities, select the main management items, and establish schedules of maintenance.

• Tribology and Lubricants
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• v.18 no.4
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• pp.285-290
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• 2002

Integrated condition monitoring is required to monitor effectively the machine conditions since machine failures could not be monitored accurately by any single measurement parameter. Application of various condition monitoring techniques is therefore preferred in many cases in order to diagnosis the machine condition. However it inevitably requires lots of maintenance cost and sometimes it could be proved to over-maintenance unnecessarily. This could happen especially when one measurement parameter closely correlates to another. Therefore correlation analysis of various monitoring parameters has to be performed to improve the reliability of diagnosis. In this work, Pearson correlation coefficient was used to analyze the correlation between condition monitoring parameters of an over-loaded machine system where the vibration, wear and temperature were monitored simultaneously. The result showed that Pearson correlation coefficient could be regarded as a good measure for evaluating the availability of condition monitoring technology.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.11a
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• pp.252-259
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• 2001

Integrated condition monitoring is required to monitor effectively the machine conditions since machine failures could not be monitored accurately by any single measurement parameter. Application of various condition monitoring techniques is therefore preferred in many cases in order to diagnosis the machine condition. However it inevitably requires lots of maintenance cost and sometimes it could be proved to over-maintenance unnecessarily. This could happen especially when one measurement parameter closely correlates to another. Therefore correlation analysis of various monitoring parameters has to be performed to improve the reliability of diagnosis. In this work, Pearson correlation coefficient was used to analyze the correlation between condition monitoring parameters of an over-loaded machine system where the vibration, wear and temperature were monitored simultaneously. The result showed that Pearson correlation coefficient could be regarded as a good measure for evaluating the availability of condition monitoring technology.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.273-295
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• 2018

In this study, an investigation of a damage detection methodology for global condition assessment is presented. A particular emphasis is put on the utilization of wireless sensors for more practical, less time consuming, less expensive and safer monitoring and eventually maintenance purposes. Wireless sensors are deployed with a sensor roving technique to maintain a dense sensor field yet requiring fewer sensors. The time series analysis method called ARX models (Auto-Regressive models with eXogeneous input) for different sensor clusters is implemented for the exploration of artificially induced damage and their locations. The performance of the technique is verified by making use of the data sets acquired from a 4-span bridge-type steel structure in a controlled laboratory environment. In that, the free response vibration data of the structure for a specific sensor cluster is measured by both wired and wireless sensors and the acceleration output of each sensor is used as an input to ARX model to estimate the response of the reference channel of that cluster. Using both data types, the ARX based time series analysis method is shown to be effective for damage detection and localization along with the interpretations and conclusions.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.263-269
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• 2012

Condition-based maintenance (CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance system as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon Hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.574-581
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• 2012

Condition-based maintenance(CBM) has been used as a useful concept for optimizing maintenance plan and decreasing maintenance cost in several kinds of plant sites. This study introduced an example that developed an integrated management system for maintenance parameters and hydraulic turbine of hydro-power plant in order to improve its maintenance strategy as applying CBM techinique. The integrated management system consists of three parts. One is a hardware part including PDA inspection system and several kind of precision measuring instruments. Another is a vibration monitoring system on hydraulic turbine. The other is a software part that takes charge of making hierarchy tree of maintenance parameters and their inspection route, managing accumulated database, assessing health condition of components, and supporting interface with other enterprise management system. The system has been installed at Chuncheon hydro-power plant for test and demonstration. It is expected that the system can contribute database construction for diagnostics and prognostics on facility health condition and systematic accumulation of know-how on operation and maintenance of plant.