• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.11
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• pp.1993-1999
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• 2011

Today, the power utilities is setting on the slow load growth and the aging of power equipment, and then could spend the efforts on the stability of system performance. Asset management may be defined as the process of maximizing corporate profit by maximizing performance and minimizing cost over the entire life cycle of power equipment. Therefore, asset management is great way to fulfill the economic investment and the stability of system performance. This paper presents the application of effective asset managem ent from an economic perspective. A proposed method is considering the life cycle analysis using life cycle cost methodology for hydro-generator during the total life cycle. The life cycle cost methodology include a way to calculating maintenance and operating costs. The proposed method will be expected to play an important role in investment decision making considering economic evaluation.

• Journal of Digital Convergence
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• v.17 no.7
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• pp.157-165
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• 2019

Geron-technology contributing to successful "Aging in place" increases the quality of life for the elderly and decreases the social caring cost. This study aims to identify influencing factors on pre-implementation acceptance of geron-technology for the elderly residing in a community. Data for 129 participants were analyzed. Results indicated that location, physical function, lack of technical support by family members, and the high financial cost as a 28% power were identified as the influencing factors on pre-implementation acceptance of geron-technology. Therefore, in the development of health and welfare strategy, these influencing factors should be considered in order to archive 'aging in place' for the elderly.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.315-316
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• 2021

The proportion of maintenance work has been increasing due to the recent aging of the infrastructure, but the standardized construction cost estimation standards are insufficient for this. In particular, reinforced concrete structures are being applied to many structures such as buildings and bridges, and various construction methods for maintenance of reinforced concrete structures are being developed and applied. In this study, we surveyed about the current status of the construction method for the maintenance work of reinforced concrete structures and analyze the factors of the revision of the construction cost estimate standard for the reinforced concrete structure maintenance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.277-278
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• 2023

The need for maintenance of bridge infrastructure is increasing due to aging, and the cost of maintaining the infrastructure must be calculated for effective budget distribution. Therefore, in this study, representative defects according to bridge superstructure type are derived to calculate the cost for each repair method. First of all, the representative bridges, PSCI girder bridge, Rahmen bridge, Steel box girder bridge, and RC slab bridge, were selected as superstructures using BMS data, and repair methods for defects were presented. In addition, the cost of the repair method by superstructure type was compared. This result is expected to predict total maintenance costs in consideration of the maintenance cycle.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.103-110
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• 2021

Elastomeric bearings composed of flexible rubber materials and steel reinforcement plates are widely used for seismic retrofit of bridges due to their excellent vertical stiffness and flexible lateral stiffness. Especially, it has the advantages of simple construction and low cost. Chloroprene rubber, a type of rubber material, has greater resistance to aging than natural rubber, but its performance is also degraded due to various deterioration factors. Although these aging characteristics are not reflected in the seismic design standards and seismic performance evaluation guidelines, it is reasonable to reflect this when related studies are accumulated. For chloroprene rubber, accelerated heat aging test was performed with variables of heating temperatures and exposure time to analyze shear characteristics. As aging progresses the maximum shear stress and shear strain decrease. Also, the shear stiffness is greatly increased at the same shear strain.

• Journal of Korean Society of Rural Planning
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• v.14 no.3
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• pp.27-36
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• 2008

Rapid increase of aging population and progressed migration from rural areas to urban areas have caused deficit of bus routes in local cities. This increasing burden of operation deficit affects the movement strategy of the transportation vulnerable who are using buses. Along with dramatically increased aging in Korea, there is an urgent need to implement a new method which can guarantee mobility rights of public transportation especially for the elderly. This study focuses on the case of Demand Responsive Transit(DRT) system that has been operating in America, Europe, Japan, etc. Kimhae(Sangdong-myeon and Saengnim-myeon) is selected as a study area. This study investigated the possibility of adopting DRT system on the perspectives of the consumer and provider by the analysis of traffic condition such as the number of transportation vehicles, present bus service and regulation and conduct of questionnaire survey which includes present bus service and DRT system and so on. In conclusion, DRT system in Kimhae city will reduce transport cost, increase affordability through the betterment of service level and secure mobility rights for the transportation vulnerable.

• Journal of Power System Engineering
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• v.20 no.5
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• pp.37-45
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• 2016

Exhaust gas recirculation has the advantage of being low-cost and easy to control of NOx emission. Therefore, it is most generally used to reduce NOx emission according to strengthen regulation. In the case of a non-road engine, such as the agricultural engine, since it mainly operate a middle or high-load state, NOx emission is decreased in accordance with the mapping range of the EGR rate, but results in an increase in the particulate matter which is caused to deposit and fouling problem of the EGR system. This problem has become an important issue for maintaining the performance of the engine, as well as emission performance. This study had examined the effects of cooler aging on the performance of heat transfer efficiency and NOx emission in non-road diesel engine. As a result of the EGR cooler aging during 200 hours engine operation, the cooling performance decreased about 25% compared with that of fresh cooler and the NOx emission increased about 14.6% on NRSC(non-road steady cycle) and 20% on NRTC(non-road transient cycle) compared with that of fresh cooler respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.138-143
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• 2004

CMP (Chemical Mechanical Polishing) technology for global planarization of multilevel interconnection structure has been widely studied for the next generation devices. Among the consumables for CMP process, especially, slurry and their chemical compositions play a very important role in the removal rates and within-wafer non-uniformity (WIWNU) for global planarization ability of CMP process. However, CMP slurries contain abrasive particles exceeding 1 ${\mu}{\textrm}{m}$ size, which can cause micro-scratch on the wafer surface after CMP process. Such a large size particle in these slurries may be caused by particle agglomeration in slurry supply-line. In this work, to investigate the effects of agglomeration on the performance of oxide CMP slurry, we have studied an aging effect of silica slurry as a function of particle size distribution and aging time during one month. We Prepared and compared the self-developed silica slurry by adding of alumina powders. Also, we have investigated the oxide CMP characteristics. As an experimental result, we could be obtained the relatively stable slurry characteristics comparable to aging effect of original silica slurry. Consequently, we can expect the saving of high-cost slurry.

• Structural Monitoring and Maintenance
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• v.2 no.2
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• pp.133-143
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• 2015

Civil engineering infrastructure is aging and requires cost-effective maintenance strategies to enable infrastructure systems operate reliably and sustainably. This paper presents an approach for determining risk-cost balanced repair strategy of corrosion damaged reinforced concrete structures with consideration of uncertainty in structural resistance deterioration. On the basis of analytical models of cover concrete cracking evolution and bond strength degradation due to reinforcement corrosion, the effect of reinforcement corrosion on residual load carrying capacity of corroded reinforced concrete structures is investigated. A stochastic deterioration model based on gamma process is adopted to evaluate the probability of failure of structural bearing capacity over the lifetime. Optimal repair planning and maintenance strategies during the service life are determined by balancing the cost for maintenance and the risk of structural failure. The method proposed in this study is then demonstrated by numerical investigations for a concrete structure subjected to reinforcement corrosion. The obtained results show that the proposed method can provide a risk cost optimised repair schedule during the service life of corroded concrete structures.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.2
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• pp.108-116
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• 2010

The maintenance of a deteriorating system is often imperfect. Previous studies have shown that the imperfect preventive maintenance (PM) can reduce the wear out and aging effects of deteriorating systems to a certain level between the conditions of as good as new and as bad as old. In this paper, we employ the concept of the improvement factor in investigating two optimal PM policies; failure limit policy and periodic PM policy. We redefine the improvement factor model as a function of the cost of PM, using this concept, we derive the conditions of optimal PM policies and formulate expressions to compute the expected cost rate. Based on this information, the determination of the maintenance policies which minimize the cost rate is examined. Numerical examples for the Weibull distribution case are also given.