• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.610-616
• /
• 2003

Recently, the common concern of nuclear power industry in the development of technology mitigating and preventing the aging of steam generator tubes prevails, because the trends of steam generator flaws at Uljin unit #1,2 and KSNP(Korea Standard Nuclear Power Plant) impose a burden on the operation of nuclear power plant. While the regulatory agency is demanding the establishment of the advanced general performance maintenance system, the steam generator management program adapting advanced technology is being developed which may comply with EPRI PWR SG Guidelines based on NEI 97-06 ‘ General Guidelines including all the maintenance aspects consist of the tube integrity assessment criteria, repair limit, allowable leakage level, water chemistry will be composed in order to obtain the approval of regulatory agency and be applied to Nuclear power plant early 2005. This presentation is to introduce maintenance state including SG tube degradation and main contents of advanced SG management program being developed, and futhermore update present and future plan, and estimate the alternation after the completion.

• International conference on construction engineering and project management
• /
• 2011.02a
• /
• pp.597-602
• /
• 2011

A robust asset management methodology is essential for effective decision-making of maintenance, repair and rehabilitation of a bridge network. It can be achieved by a computer-based bridge management system (BMS). Successful BMS development requires a reliable bridge deterioration model, which is the most crucial component in a BMS, and an optimal management philosophy. The maintenance optimization methodology proposed in this paper is developed for a small bridge network with limited structural condition rating records. . The methodology is organized in three major components: (1) bridge health index (BHI); (2) maintenance and budget optimization; and (3) reliable Artificial Intelligence (AI) based bridge deterioration model. The outcomes of the paper will help to identify BMS implementation problems and to provide appropriate solutions for managing small bridge networks.

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

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.7-13
• /
• 2011

RAMS is the procedure to maximize the reliability and availability of systems with managing operation rate, the frequency of failure in the system and repair method. Recently, all system life-cycle focusing on RAMS process has been rapidly developing in the field of railway vehicles, for example, applying th reliability management techniques for procurement and disposal of EMU. In particular, global economic recession require to reasonable measures for the EMU maintenance costs under the circumstances therefore, an alternative solution based on RCM(Reliability Centered Maintenance) which is the optimal maintenance method is interested. In this study, the state of being critical of each component and a primary factors was analyzed to improve VVVF inverter of the line 7 EMU by applying FMECA process. Furthermore, this paper showed the impact of connecting between the main and sub system. Based on these data, critical components according to malfunction ratings were classified by screening measures and improvements for each components was summarized.

• Proceedings of the KSR Conference
• /
• 2009.05a
• /
• pp.84-90
• /
• 2009

The gravel ballast in the ballasted track has the function to not only transfer/scatter the train loads to subgrade through rail and sleeper but also elastically support the train loads. Because track irregularities results inevitably from the repetitive train loads, the track maintenance should be undertaken for correcting them. By analyzing the track maintenance history in the Gyeongbu high speed railway, this study tries to choose the local two spots in the railway in which the repair frequencies are maximum and relative small; to analyze their dynamic characteristics as well as grade; and to compare them with maintenance history. As the dynamic characteristics of track, the vertical displacement and vibrating acceleration of sleeper as well as acceleration of ballast are measured/analyzed. Furthermore, by collecting soil and gravel on the reinforced roadbed and undertaking ballast screening test, the size distributions are compared with grade distribution standards of high speed railway.

• KIEAE Journal
• /
• v.3 no.3
• /
• pp.67-74
• /
• 2003

The repair and maintenance planning is the principal transaction to prevent from the degradation of apartment buildings to prolong their lives. Various building components as part of living area should be maintained properly and timely before critical defects are realized, then the building life might be extended until the limit of its usability. In other words, various building components such as utilities, finishes and structural members are needed to be repaired and replaced in different time interval after completion. To do this systematically, a maintenance management system for Long-Range Planning (LRP) needs developing. The LRP should be figured out based on the forecast of repairing and replacing cycle of building components according to work trades. And the precise forecast of repairing and replacing time of the components helps to enhance the usability of the developed system. The purpose of this paper is to suggest a system with which apartment building managers carry out the tasks of periodical check, diagnosis and replacement of building components based on the maintenance calendar. By using the system, they can easily forecast repairing and replacing time of the components with the consideration of life cycle of building materials and build the LRP.

• Smart Structures and Systems
• /
• v.30 no.6
• /
• pp.571-582
• /
• 2022

Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.

• Asia pacific journal of information systems
• /
• v.16 no.2
• /
• pp.143-158
• /
• 2006

This paper considers probable determinants of the application software outsourcing costs and focuses on the service level agreement (SLA) influence. Recently, outsourcing clients and vendors have contracted SLA and tried to reflect them on outsourcing prices. While application software maintenance has been one of the most frequently outsourced functions, its cost did not reflect the service level requirements by the client. This paper empirically shows that the service urgency requirement on SLA increases the maintenance programmers' effort and thus increases the vendor's cost. This result can be used by vendors for program allocation purposes.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.337-346
• /
• 2008

In this paper, a study an standardization of control cable numbering for high speed railway substation. Standard numbering structure of substation control cable and consistency of the number system are important for the railway substation construction and maintenance. However, currently control cable number system of railway substation was not standardization which was different according to a bander and a construct company. Therefor there is many difficult which does a same function to differ in maintenance and repair to accident. Therefor Standardizes the number system of the substation control cable is useful for an improve of construction and maintenance.

• Journal of the Korean Society of Safety
• /
• v.25 no.6
• /
• pp.115-122
• /
• 2010

The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.