• International Journal of Highway Engineering
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• v.19 no.6
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• pp.75-81
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• 2017

PURPOSES : So far, aged cement concrete pavement on express highways has been rehabilitated mainly with asphalt concrete inlay. However, potholes were the major problem, and they shortened the life of the inlay mainly owing to the poor drainage of water once it infiltrated the interface of the concrete and asphalt. The purpose of this study is to compare the performance and economic efficiency of asphalt overlay and inlay. METHODS : Overlay and inlay were compared through accelerated pavement testing, and a life-cycle cost analysis was conducted in this study using the CA4PRS program. RESULTS and CONCLUSIONS : It was found from accelerated pavement testing that the overlay exhibited reflective crack resistance that was more than twice as effective as that of inlay. The total cost (construction cost + user cost) within the analysis period (20 years) of the overlay was 37% lower than that of the inlay.

• Clean Technology
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• v.12 no.4
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• pp.217-223
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• 2006

The operating variables of a desorption step were experimentally investigated tor the cycle of the process made up of benzene adsorption, steam desorption, and drying step. The effect of adsorbent regeneration depending on existence and nonexistence of drying step was studied by breakthrough curves obtained in the adsorption step of the second cycle. The duration of drying step was determined by the experimental results. In case that the amount of nitrogen gas was fixed, the regeneration efficiency increased with the amount of steam. However, the effect of steam decreased as the amount of nitrogen increased. Therefore, it would be possible to predict the optimum amount of steam comparing the amount of nitrogen gas with amount of steam in economic view.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.141-150
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• 2004

Recently, it is really concerned about corrosion and aging of reinforced concrete bridges. Corrosional steel reinforcing in concrete affects not only safety of bridges structure but also bending strength of reinforced concrete's member. Rate of corrosion, characteristic of bending strength, and economical evaluation aren't clear in reinforced concrete, considering performance evaluation. The purpose of study is as follows. It studies about ability of resistance's strength and cost of life cycle according to reduction of steel reinforcing's corrosion. Moreover, it shows calculating formula of bending strength with corrosion of current rate and exactly evaluates about the rest life at corrosional reinforced concrete bridges.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.3
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• pp.119-126
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• 2017

Recently, ground source heat pump systems are being used in buildings for cooling and heating to reduce greenhouse gas and save energy. However, ground source heat pump systems mainly use the vertical closed-loop geothermal system design rather than the open-loop geothermal system design. This is due to a lack of knowledge and few research feasibility studies. In this research, a dynamic thermal analysis numerical simulation based on a standard house model was conducted for an open-loop geothermal system. Based on heating load analysis results, the life cycle costs of a standard house using an open two-well geothermal system were analyzed and compared with a vertical closed-loop geothermal system, and a diesel boiler. As a result, it was found that using an open two-well geothermal system shows economic return on investment after three years.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.5
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• pp.39-45
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• 2013

Wind power is one of the fastest growing renewable energy sources. In these days, wind turbine shifts from onshore to offshore because the offshore wind farm has a abundant wind resource. However, offshore wind turbine is not easy to access, it has a long downtime when the failures of the wind turbine component occur. Therefore, the appropriate wind turbine maintenance plan is required to meet the economic and reliability of the components. This paper proposes the maintenance planning method based on the RCM(Reliability Centered Maintenance) to determine an economical maintenance cycle to satisfy the appropriate reliability of the wind turbine components. In order to compare the proposed method with the conventional RCM method, critical components are selected in the case study because they have a long downtime and a large amount of total cost.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.233-235
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• 2017

Forklift tend to work in place rather than moving due to work environment conditions, so they express only the engine operation time without expressing the moving distance unlike a general car's instrument panel. Therefore, various consumables constituting the forklift have a replacement cycle according to the operation time of the engine. However, it is very difficult to judge the exact replacement cycle only by the engine operation time because the working environment differs for each forklift. In this paper, we propose a system that provides position information and moving distance information of forklift to driver using GPS and IMU sensor. By using this system, it is expected that the forklift status information, which is difficult to judge by the existing instrument panel, is provided as easier information, and economic benefits for forklift management and maintenance are expected.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1253-1258
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• 2006

As a global effort to conservate the environment, life cycle assessment(LCA) which considers the environmental impact through the life cycle of a product, from acquiring of resources to scrapping, has been actively applied. The LCA is a tool to calculate quantitatively the environmental impacts caused by products or services through their life cycles. Eco-efficiency need that express value of environmental impact provision EMU and develops in two forms according to use target of Eco-efficiency as a tool that environmental impact of EMU. It is a strategic instrument which assists stakeholders to understand which products, processes or services to target with future investments and which are not by comparing economic and ecological values. The results stand for aggregated information on economical value and environmental impact. Also, In this method, it is important to derive EPI(Environmental Performance Index) and SPI(Service Performance Index) from the sources available. The following is used as one of Eco-efficiency tools to achieve the target performance of processes, products and services for designer or projector. According to the eco-efficiency methodology for EMU developed in this study, the user definition and the DB design were carried out as a basic design of eco-efficiency S/W.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.917-920
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• 2007

Private companies will get back their investment by leasing facilities to the government, Since act on private participation in infrastructure were changed in January 2005, BTL(Build Transfer Lease) project of introduced in the domestic construction market for the purpose of providing public facilities with the public. BTL projects is for with approximately project life cycle form plan to maintenance the success of the project totally depends on the capability and role of concessionaire. Accordingly, this study is aimed to improve in order to proceed with BTL project efficiently, a clear standard for the item of evaluation was presented.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.488-493
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• 2018

The Firebrick Resistance-Heated Energy Storage (FIRES) concept developed by the Massachusetts Institute of Technology aims to enhance profitability of the nuclear power industry in the next decades. Studies carried out at Massachusetts Institute of Technology already provide estimates of the potential revenue from FIRES system when it is applied to industrial heat supply, the likely first application. Here, we investigate the possibility of operating a power plant (PP) with a fluoride-salt-cooled high-temperature reactor and a closed Brayton cycle. This variant offers features such as enhanced nuclear safety as well as flexibility in design of the PP but also radically changes the way of operating the PP. This exploratory study provides estimates of the revenue generated by FIRES in addition to the nominal revenue of the stand-alone fluoride-salt-cooled high-temperature reactor, which are useful for defining an initial design. The electricity price data is based on the day-ahead markets of Germany/Austria and the United States (Iowa). The proposed method derives from the equation of revenue introduced in this study and involves simple computations using MatLab to compute the estimates. Results show variable economic potential depending on the host grid but stress a high profitability in both regions.

• Fashion & Textile Research Journal
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• v.23 no.5
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• pp.598-610
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• 2021

Korean textile and fashion companies have played a major role not only in developing the Korean economy since Korea's industrialization started in the early 1960s but also in providing opportunities to form and expand chaebols (conglomerates of family-owned businesses). This study reviewed and analyzed the historical development of chaebols, which started the fiber/textile/fashion business before the 1960s and maintained their chaebol status until 2010. The Samsung, Samyang, Kolon, Taekwang, Hyosung, LG, and SK groups were included in the study, and data were collected from diverse sources, including the publications and websites of the chaebol companies, newspapers, magazines, and research articles. The strategies of the companies at the corporate and group levels were examined based on the corporate lifecycle, which consists of existence, growth, maturity, rebirth, and decline stages. The results showed that all the analyzed companies actively engaged in product line expansion during the growth stage. Vertical integration, especially backward integration, was common during the growth stage. Some groups established new companies to manage additional product lines and integration, while others pursued growth strategies mainly at the corporate level. The rebirth stage occurred in only a few companies and groups. Some seemed to be going through the decline stage, and the rest of the groups exited the textile and fashion business.