• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.73-83
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• 2010

This study was performed to increase the removal efficiency of the biofilter packed with granular sulfur in municipal wastewater reclamation facility. Constituent units were influent water tank, denitrification tank, BOD reduction tank and outlet. And, the major operation factor is a biofilter packed with submerged granular sulfur. Actual wastewater and synthetic wastewater were used as influent wastewater. Experimental condition was divided into two phases according to the amount of a phosphorus coagulant. Total phosphorus removal efficiency was insignificant at mode I that phosphorus coagulant was not injected. The average influent and effluent total phosphorus concentrations at mode II were 0.5 ~ 1.0 mg/L and 0.27 mg/L, respectively. As for COD and BOD effluent concentrations, COD was 3.0 mg/L and BOD was 1.0 mg/L. Additionally, nitrogen removal rates were high at low influent DO concentration. In conclusion, a new process, biofilter packed with granular sulfur is expected to treat high-rate nitrogen wastewater and expected to be utilized as an alternative of technological innovation for the nitrogen treatment.

• Journal of KIBIM
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• v.10 no.2
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• pp.12-20
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• 2020

Recently, interest in BIM technology has been growing in the domestic construction market as the number of construction projects requiring the application of BIM technology has increased. The use of BIM allows the use of various visualization functions through 3D models as well as drawing interference review, quantity calculation and integrated management of information. In particular, estimates of construction costs based on BIM can increase work efficiency by reducing the burden of calculating construction costs and managing them. In order to increase the efficiency of BIM-based cost estimates, it is necessary to improve the correlation between the BoQ(Bill of Quantity) information and the BIM model. For this purpose, the ratio of the amount and item to the detailed construction of the current BoQ was analyzed, especially the problem of the calculation of construction cost in the window work in this study. In addition, we would like to suggest a method for systematically linking the BoQ information with the BIM model by improving the BoQ information structure of the window work. It is expected that this will increase the efficiency of the quantity calculation and analysis work of construction cost of window work. In addition, it is expected that this method will help to analyze and predict changes in construction cost of windows and doors by facility characteristics and type.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.5
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• pp.416-423
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• 2009

High-temperature steam electrolysis (HTSE) using solid oxide cell is a challenging method for highly efficient large-scale hydrogen production as a reversible process of solid oxide fuel cell (SOFC). The overall efficiency of the HTSE hydrogen and synthesis gas production system was analyzed thermo-electrochemically. A thermo-electrochemical model for the hydrogen and synthesis gas production system with solid oxide electrolysis cell (SOEC) and very high temperature gas-cooled reactor (VHTR) was established. Sensitivity analyses with regard to the system were performed to investigate the quantitative effects of key parameters on the overall efficiency of the production system. The overall efficiency with SOEC and VHTR was expected to reach a maximum of 58% for the hydrogen production system and to 62% for synthesis gas production system by improving electrical efficiency, steam utilization rate, waste heat recovery rate, electrolysis efficiency, and thermal efficiency. Therefore, overall efficiency of the synthesis production system has higher efficiency than that of the hydrogen production system.

• Asia-Pacific Journal of Business
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• v.12 no.2
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• pp.1-24
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• 2021

Purpose - We aim to verify whether CSM activities increase investment efficiency, and to verify whether the influence of CSM activities on investment efficiency is discriminatory depending on whether or not they belong to chaebol. Design/methodology/approach - Using 4,701 Korean firm-year observations over the 2011-2017 period, we used multiple regression analysis. CSM is measured by the evaluation score of the Korea Corporate Governance Service (KCGS). Findings - Our study confirms that CSM is a significantly positive relationship with investment efficiency. This shows that, as a result of CSM, the increased earnings quality acts as an incentive to increase investment efficiency. Next, in analysis of a dataset into two groups (a chaebol, non-chaebol), the results show that the relationship between CSM and investment efficiency differs among detailed indicator activities depending on whether or not they belong to chaebol. Research implications or Originality - It is significant that this study focused on and analyzed CSM as a determinant of investment efficiency, and examined the effects of whether or not it belongs to chaebol in the relationship between CSM and investment efficiency. Our results, which suggested that CSM can increase investment efficiency, are expected to provide important implications not only for managers but also for investors and supervisors.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.32
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• pp.233-242
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• 1994

This study deals with the derivative adverse minimum for inferiority system depends on continuose operating under infinite planning horizon. This planning will be accomplished by maintenance limit renewal policy in consideration of opportunity cost which affects system by failure during operation periods and expected cost under nomal operation states. By the results, we will be expected incresing total efficiency for the system by optimal renewal policy.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.52
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• pp.97-118
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• 2011

85% of South Korea's gross domestic product(GDP) depends on trade. Exports amount in 2011 exceeds $ 5,000Billion. Korea is expected to achieve $ 1 trillion in total trade volume and will become finally the ninth in the world. We do not have a lot of natural resources and are bound to export the finished products to pursue economic development. In other words, trade sector is very essential for Korea to continue economic growth. The department of trade in universities have brought up the concerned students serving for trade sectors. Currently, "half-price tuition" in universities has become very controversial issue in Korea so this paper studies the efficiency of "the Department" because the universities may reconsider the adjustment of tuition fee, if they can enhance the efficiency level. DEA model is used for the analysis. As a result, 8 DMUs like KAN1, KEI5, BAE10 etc. show relatively higher efficiency levels.

• Journal of Electrical Engineering and Technology
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• v.8 no.5
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• pp.1221-1226
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• 2013

In this paper, the equivalent circuit for the efficiency calculation by precise estimation of the linkage flux, inductance and iron loss resistance was calculated accurately. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated. And then, analyzed and experimental values of the efficiency were compared. So, causes of error were expected to be vibration and noise by harmonic distortion of the voltage and current, and mechanical loss of dynamometer. In addition, the driving characteristics according to the current phase angle are analyzed and the maximum efficiency point is calculated.

• International journal of advanced smart convergence
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• v.9 no.2
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• pp.179-184
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• 2020

Recently, webtoons-based animations have been expanding in Korea, where the role of mobile devices is growing, and media videos such as "YouTube" and "Tik-Tok," which have shorter screening and production cycles than traditional feature films, dramas, and animations, are attracting attention and being enjoyed by public. In order to produce animation content that fits the trend of this shortening video and production cycle, efficiency must be increased not only in story but also in production. Production methods and production technologies need changes to increase efficiency. Animation using motion capture, which is highly production-efficient, is widely used in movies that shows realistic movements, but still has little use in producing cartoon-style animations with exaggerated movements. We analyzed the production method of 2D animation and CG animation and applied the result to CG animation to increase the efficiency of production and production. The methods of production through such experiments are expected to help improve the efficiency of producing animation content that is suitable for the latest trends such as webtoon animation.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2971-2976
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• 2008

Recently, there has been growing interest in the oxyfuel combustion cycle since it enables high-purity CO2 capture with high efficiency. However, the oxyfuel combustion cycle has some important issues regarding to its performance such as the requirement of water recirculation to decrease a turbine inlet temperature and proper combustion pressure to enhance cycle efficiency. The purpose of the present study is to analyze performance characteristics of the oxyfuel combustion cycle with different turbine inlet temperatures and combustion pressures. It is expected that the turbine inlet temperature improves cycle efficiency, on the other hand, the combustion pressure has specific value to display highest cycle efficiency.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.4
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• pp.221-226
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• 2018

In this paper, the power transfer efficiency analysis based on the resonant repeater in a magnetic resonance wireless power transfer system is proposed. The efficiency of the magnetic resonance method was verified by comparing the general frequency with the resonance frequency. The resonance repeater was arranged to increase the efficiency and increase the transfer distance. When using resonant repeaters, the maximum efficiency increase is about 36.23[%] and the transfer distance was extended to more than 20[cm]. Through this study, confirmed the effect of using resonance repeaters in wireless power transfer system. As a result, it can be expected that the overall technology related to wireless power transfer system will be more valuable for energy-IT technology.