• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.167-174
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• 2007

This study proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the and the life-cycle cost and performance as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6A
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• pp.1023-1032
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• 2006

In this paper, a new method for the bridge maintenance is proposed to overcome the limit of the existing methods and to implement the preventive bridge maintenance system. The proposed method can establish the lifetime optimum maintenance strategy of the deteriorating bridges considering the life-cycle performance as well as the life-cycle cost. The lifetime performance of the deteriorating bridges is evaluated by the safety index based on the structural reliability and the condition index detailing the condition state. The life-cycle cost is estimated by considering not only the direct maintenance cost but also the user and failure cost. The genetic algorithm is applied to generate a set of maintenance scenarios which is the multi-objective combinatorial optimization problem related to the life-cycle cost and performance. The study examined the proposed method by establishing a maintenance strategy for the existing bridge and its advantages. The result shows that the proposed method can be effectively applied to deciding the bridge maintenance strategy.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.5
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• pp.21-28
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• 2012

Current maintenance costs of the educational facilities have been determined by the years of services according to their foundation year. However, these maintenance costs have not considered maintenance and repairing. Therefore, this study suggests a new method to recalculate the years of services of schools by using the data of maintenance and repairing which is stored in the CAD drawing of the educational facilities. Also, since the data of maintenance and repairing has to be kept only for 5 years, the data is limited for the BTL project which has a maintenance period of 20 years. Thus, this study developed a new model to expand 5 years' data to the period of 20 years. This proposed model is expected to contribute in the maintenance and repairing of the BTL project.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.331-340
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• 2009

This study is objected by suggesting rationalization method of management and maintenance cost for railway investment assessment. The estimate of rational benefit and cost are a work of vital importance to decide railway investment as preliminary feasibility investigation is institutionally reinforced since January 2007. In particular, railway management and maintenance cost have to be applied to realistic and detail cost as railway investment assessment guide. For example, types of railway, construction of new line, improvement of conventional line, double tracking, railway electrification. However, railway investment assessment is inconsistency because of estimating the railway management and maintenance cost using existing unrealistic management and maintenance cost. Therefore, this study is performed parametric analysis effecting on the railway management and maintenance cost considered new technique, enhanced facilities and improved standard. Also, it suggests the itemized standard management and maintenance cost. Finally, it will be helped to establish the base of railway investment through the rationalization method of management and maintenance cost.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1487-1493
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• 2008

Railway vehicle is very important to implement the effective maintenance in proper to prevent any failure during operation period. Many railway authorities are making efforts to maintain the railway vehicle through scientific and systematic procedure. To achieve this, Reliability Centered Maintenance(RCM) is partially applied. The efficiency of RCM has proven and its terminology was familiar with nuclear power, military and chemical plant etc. since the commercial aircraft's industries has introduced the maintenance program based on the target of reliability. The application of RCM on railway vehicle can be utilized with systematic analysis method to select the best effective maintenance period and action to prevent the failures by selecting the equipment affecting the its safety and reliability. This paper is presented that the procedure of adequate and effective maintenance for railway vehicle by comparing among the related standards in example IEC60300-3,11, MIL-STD-2173, and technical documents or papers. In accordance with above result, RCM procedure is proposed to apply effectively for maintenance of railway vehicle. That is, (1) Analysis of data and Calculation of criticality per equipment (2) Selection of equipment to analyze (3) Analysis of failure mode and effect (4) Evaluation of maintenance method and period (5) Optimization of maintenance program through renewal of maintenance method and period.

• Journal of Information Technology Services
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• v.21 no.3
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• pp.43-61
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• 2022

With the development of information technology, IT-based services in public administration has become more indispensable. As a result, the importance of IT maintenance projects to improve the efficiency of IT services and secure service levels is growing. Due to the nature of IT maintenance projects on local government, which mainly involve small and medium-sized IT companies in the region, business participating companies often do not have an appropriate methodology for service quality management. To solve this situation, the government has prepared a service level agreements (SLAs) that can be applied to IT maintenance projects. However, most local governments do not use SLAs for IT maintenance projects. As a result, various problems such as failure of the IT maintenance project or deterioration of quality are occurring Thus, this paper suggested major indexes to evaluate which service factors affect the efficient operation of information systems and the improvement of service quality in IT maintenance projects of local governments and analyzed the importance of indexes based on AHP method. Using this research method, this study found the theoretical implications on the outsourcing service of IT maintenance.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.303-308
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• 2000

By means of analyzing of monitoring technology and monitoring regulation based on maintenance monitoring system installed in subway tunnel section, it needs monitoring system, development of operating program, monitoring analyzing system and development of analysis method, establishment of maintenance monitoring standard specification, and performance of responsible monitoring supervision for applying to subway monitoring maintenance effectively in future. It requires specialized monitoring and legislation of monitoring subcontract, improvement of monitoring work contract method, establishment the standard payment of monitoring, and effective calibration and correction of monitoring system in the plan of improving monitoring regulation.

• Journal of Information Technology Services
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• v.14 no.3
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• pp.67-84
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• 2015

Software is more diverse and complex and the level of importance for the maintenance of application software to securely operate software is also gradually increasing in proportion. The calculation method for maintenance cost of application software applied in Korea public enterprises is involved in the range of 10 to 15% of development cost, depending on the Software Project Cost Estimation Guide. Moreover, as most software maintenance cost estimation procedures do not take into consideration of the risk factors related of maintenance, it can be seen as a main cause for the occurrence of maintenance related accidents. This study proposes a maintenance cost estimate model that takes into consideration of the risks related to the software maintenance activities to improve and resolve issues arising from the estimation of maintenance cost. In doing so, maintenance risk factors are analyzed and a risk index is derived through the analysis of risk levels based on the risk factors. Based on such analysis, a maintenance cost estimate method which reflects the maintenance risk index was established.

• Journal of architectural history
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• v.23 no.4
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• pp.19-33
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• 2014

Recently, conservation and utilization of cultural heritage has been regarded as importance. So, various research papers about maintenance of the remains have been presented in many conferences. But most of researches have focused on introduction about maintenance methods and explanation about maintenance concepts of remains. And even in case of a few papers treated post-evaluation about maintenance of the remains the criteria of the evaluation has tended to somewhat subjective. So, the purpose of this study is to show the objective post-evaluation indexes which was developed by Delphi AHP methods. This research was proceeded in two stages. First, we arranged the evaluation index in a hierarchy to be made through the analyses about references and researches about maintenance of remains. 304 evaluation articles were elicited through the process. And then, elicited evaluation articles were classified with 'conservation' and 'utilization'. Second step was to figure out importance and validity of hierarchical evaluation articles with twice questionnaire surveys. This research used interval scale to comprehend validity and AHP method to evaluate relative importance of each other articles.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.9-11
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• 2006

This paper suggests a revision method for historical fault data using Proportional Aging Reduction(PAR) to consider maintenance effect in time-varying failure rate. In order to product time-varying failure rate, the historical fault data are necessary. However, the maintenance record could be left out in historical data by spot operator's mistake. In this case, the failure rate is produced less than the average failure rate for increasing equipments' life-time by maintenance effect. Hence, it is necessary for new time-varying failure rate to extract maintenance effect from the existing fault data. In this paper, the revision method to reduce equipments' life-time, adversely using PAR among three techniques to consider maintenance effect.