• Journal of Wind Energy
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• v.14 no.3
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• pp.34-42
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• 2023

The reduction of operation and maintenance (O&M) costs is a critical factor in determining the competitiveness of wind energy. Predictive maintenance based on the estimation of remaining useful life (RUL) is a key technology to reduce logistic costs and increase the availability of wind turbines. Although a mechanical component usually has sudden changes during operation, most RUL estimation methods use the trend of a state index over the whole operation period. Therefore, overestimation of RUL causes confusion in O&M plans and reduces the effect of predictive maintenance. In this paper, two RUL estimation methods (load based and data driven) are proposed for the bearings of a wind turbine with the results of trend classification, which differentiates constant and increasing states of the state index. The proposed estimation method is applied to a bearing degradation test, which shows a conservative estimation of RUL.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.1
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• pp.96-101
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• 2014

Wind power is the fastest growing renewable energy source in the world and it is expected to remain so for some times. Recently, there is a constant need for the reduction of Operational and Maintenance(O&M) costs of Wind Energy Conversion Systems(WECS). The most efficient way of reducing O&M cost would be to utilize CMS(Condition Monitoring System) of WECS. CMS allows for early detection of the deterioration of the wind generator's health, facilitating a proactive action, minimizing downtime, and finally maximizing productivity. There are two types of faults such as mass unbalance and aerodynamic asymmetry which are related to wind turbine's rotor faults. Generally, these faults tend to generate various vibrations. Therefore, in this work a simple fault detection algorithm based on spectrums of vibration signals and simple max-min decision logic is proposed. Furthermore, in order to verify its feasibility, several simulation studies are carried out by using GH-bladed software.

• Journal of the Korean Society of Systems Engineering
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• v.18 no.1
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• pp.99-104
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• 2022

In this paper, to increase the maintenance efficiency of the urban railway train control system and to build a standard data system, we collect as much as possible structured, unstructured, and semi-structured data, and collect data by sensing and monitoring the system status and system status and monitoring. pre-process function data(Identification, purification, integration, transformation) through effective data classification and maintenance activities business classification system was studied. The purpose of this is to define the data matrix model by considering the relationship with the data generated and managed in the O&M stage of the train control system operated by the urban railway together with the WBS model, and to reflect and utilize it in practice.

• KIEAE Journal
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• v.13 no.6
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• pp.99-104
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• 2013

Many activities associated with the construction and habitation of buildings are connected with issues affecting the environment such as global warming, climate change, and consumption of valuable natural resources such as fossil fuels. To minimize negative impacts on the environment, the building industry worldwide has implemented green building practices in many countries. One of the main green strategies is to reduce greenhouse gas emissions caused by residential structures because they are most substantially connected with global warming and climate change. To determine the actual quantity of green house gas emissions caused by the construction and use of a building, it is important to analyze total greenhouse gas emissions over the life cycle of buildings including construction, operation & maintenance(O&M) and demolition stages. Many studies suggest methods to calculate greenhouse gas emissions at the construction stage, but the literature addressing greenhouse gas emissions at the O & M stage is limited. A year-long study was conducted utilizing the deterioration method to calculate greenhouse gas emissions at the O & M stage of building life for condominium types of buildings in South Korea. Through this research, it is possible to analyze greenhouse gas emissions of buildings at the O & M stage, the longest span of the life cycle, and eventually help to calculate total greenhouse gas emissions over the life cycle of the building.

• Current Photovoltaic Research
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• v.10 no.4
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• pp.133-137
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• 2022

The economic feasibility of a photovoltaic (PV) system is greatly influenced by the initial investment cost for system installation. Also, electricity generation by PV system is highly important. The profits competitiveness of PV system will be maximized through intelligent operation and maintenance (O&M). Here, we developed a microconverter which can maximize electricity generation from PV modules by tracking the maximum power point of PV modules, and help efficient O&M. Also, the microconverter mitigates current mismatch caused by shading, hence maximize power generation. The microconverters were installed PV modules and demonstrated through the field tests. Power outputs such as voltage, string current were measured with variuos weather environments and partial shadings. We found that PV modules with the microconvertors shows 12.05% higher power generation compared to the reference PV modules.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.655-662
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• 2010

As the national competitive power indicator, the infrastructures have been constructed with government's SOC budgets. However, even SOC budget is decreased, Public-Private Partnership Project (PPP project) has been introduced to solve demands on extending infrastructures, and among PPP projects, road projects take high portions. This study analyzes the operation & management item of financial model which is connected to the O&M cost and project proposal of previously proposed road project and analyzes the Korea Expressway Co.,'s project cost items and O&M tasks to reflect the characteristics of road projects. Based on results, this study suggests necessity of the O&M cost breakdown structure and the cost calculation standard on each cost item. Also, for the existing task execution tools, O&M cost calculation tool and finance analysis task tool will be integrated, and the system is suggested web-based system. Thus, it is expected that it contributes to the securing overall business values on PPP project and expending profit-base infrastructures.

• Journal of Korea Multimedia Society
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• v.23 no.10
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• pp.1307-1317
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• 2020

In recent years, the PV plant is gradually increasing in korea and has begun to focus on PV system O&M(Operation and Management). The legacy PV system can hardly be gathering realtime information. That is why it is difficult for the facility to respond immediately to situations in which problems arise. This leads to economic losses due to reduced power generation. In this study, we implemented an RMC(Remote Maintenance Control) gateway that supports multi-area equipment(inverters, junction boxes, switchboards, environmental sensors) that are not limited to specific manufacturers. It provides a function to visualize the collected data. Users can easily check the power generation and operation status of PV system equipment. In the future, we will develop an algorithm capable of analyzing beta factors that cause equipment performance degradation, parts aging, and deterioration using data collected from facilities. We intend to use this algorithm as a fundamental technology for O&M by transplanting it to the RMC gateway.

• 열병합발전
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• s.59
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• pp.9-13
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• 2007

한국전력 해외사업본부에서 나이지리아 엑빈발전소 O&M(Operation and Maintenance) 및 보일러 복구공사를 추진하고 있으며, 보일러 복구공사는 현재 수행이 되고 있다. 이와 관련하여 전력연구원에서는 엑빈발전소에서 발생한 보일러 폭발 발생원인과 대책을 수립하기 위하여 현장 진단을 수행하였다. 따라서 보일러 폭발에 대한 발생 Mechanism과 대책을 소개함으로서 보일러 유지관리에 참고가 되고, 보일러 폭발과 같은 대형사고를 방지하는데 도움이 되기를 바란다.

• Journal of Computational Design and Engineering
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• v.2 no.2
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• pp.119-127
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• 2015

In the case of a high-valuable asset, the Operation and Maintenance (O&M) phase requires heavy charges and more efforts than the installation (construction) phase, because it has long usage life and any accident of an asset during this period causes catastrophic damage to an industry. Recently, with the advent of emerging Information Communication Technologies (ICTs), we can get the visibility of asset status information during its usage period. It gives us new challenging issues for improving the efficiency of asset operations. One issue is to implement the Condition-Based Maintenance (CBM) approach that makes a diagnosis of the asset status based on wire or wireless monitored data, predicts the assets abnormality, and executes suitable maintenance actions such as repair and replacement before serious problems happen. In this study, we have addressed several aspects of CBM approach: definition, related international standards, procedure, and techniques with the introduction of some relevant case studies that we have carried out.

• Journal of the military operations research society of Korea
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• v.28 no.1
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• pp.97-114
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• 2002

An estimation of economic life for a new weapon system is a critical issue in aquisition process. In general a life cycle cost consists of, development cost, aquisition cost, and maintenance cost. These costs are not identified and obtained in the beginning of the aquisition process. This paper deals with an economic life for KlAl tank which is being deployed recently, using PRICE model. In order to estimate an KlAl economic life, we use equivalent annual cost method which is sum of capital recovering with return and equivalent O&M cost method. This method determines an economic life by minimizing annual investment cost and operation and maintenance cost. In this paper, an aquisition cost of KlAl is obtained from PRICE H and O&M cost from PRICE HL model. We obtained various results depending upon production quantity. An economic life for KlAl is estimated 18 years when 300 tanks are produced.