• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.602-612
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• 2001

The equation of the particle collection efficiency proposed by Deutsch has been modified through the various experiments to correct the errors caused by the assumptions made for the equation. In order to get an modified Deutsch equation that can be applied to real conditions, a pilot scale electrostatic precipitator is used. The effects of operational variables on the particle collection efficiency are evaluated. Particle resistivity, gas temperature, moisture contents in gas, gas velocity and particle concentration are used as the operational variables. Two different types of coal fly-ash obtained from the fluidized bed combustor and the pulverized coal combustor are used as test particulate to evaluate the effect of the physiochemical and electrical characteristics of the particle on the particle collection efficiency. The experimental results are fitted with the modified Deutsch equation made by Matts-Ohnfeldt and the extended Deutsch equation made by E. C. Potter to evaluate the effect of the particle characteristics and the operation conditions on the particle collection efficiency of the electrostatic precipitator.

• The Journal of Fisheries Business Administration
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• v.26 no.2
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• pp.133-146
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• 1995

WTO system has just begun and the development for fishing industry is being carried out. The task of National Federation of Fisheries Cooperatives(NFFC ) is not only to support producers' competitive edge, but also to realize the efficiency embodied in the businesses of NFFC itself. Then it can continue to compete other firms and offer the comprehensive services only when it achieves its efficiency. The efficiency of NFFC is the economies of scale and scope. NFFC should achieve its scale and scope economies to be efficient. NFFC needs to expand its size in fish distribution and banking business to have scale economies. Also, the communication and coordination systems among member-supporting, fish distribution, and banking business need to be strengthened to get its scope economies. It is interesting theoretically and in policy making to test the hypotheses that cooperatives are capable of offering the comprehensive services such as distribution, credit, and insurance to the members. It is meaningful to their development for agricultural and small businesses cooperatives as well as fisheries cooperatives to survive the fierce competition under WTO system. National Federation of Agricultural Cooperatives(NFAC) is much greater in business size than NFFC. The estimation and test in the multiproduct cost function of NFAC will show interesting results.

• International Journal of Aeronautical and Space Sciences
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• v.9 no.2
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• pp.79-86
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• 2008

High performance direct-iterative hybrid linear solver for large scale finite element problem is developed. Direct solution method is robust but difficult to parallelize, whereas iterative solution method is opposite for direct method. Therefore, combining two solution methods is desired to get both high performance parallel efficiency and numerical robustness for large scale structural analysis problems. Hybrid method mentioned in this paper is based on FETI-DP (Finite Element Tearing and Interconnecting-Dual Primal method) which has good parallel scalability and efficiency. It is suitable for fourth and second order finite element elliptic problems including structural analysis problems. We are using the hybrid concept of theses two solution method categories, combining the multifrontal solver into FETI-DP based iterative solver. Hybrid solver is implemented for our general structural analysis code, IPSAP.

• Journal of Environmental Science International
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• v.11 no.10
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• pp.1117-1123
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• 2002

Coating ceramic balls activate water molecular in water as radiate far-infrared radiation of high efficiency, and then prevent formation of scale and corrosion of pipe. Therefore, but only keep away drop of heat exchange efficiency of boiler, not also remove formed scale. As a result, pipe of boiler has clean and has form thin protection film in inner of pipe. Also, the water treated by rust preventing system using the ceramic balls, that is harmless, tasteless, odorless, and non-toxicity in the human body, and it can use drinking water. This rust preventing system can save energy and protect environment.

• International Commerce and Information Review
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• v.19 no.3
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• pp.45-61
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• 2017

The purpose of this study is to examine the efficiency of Korean companies' entry strategy in India through the DEA model and to review the current status and competitiveness of Korean companies in India. To analyze 112 companies that entered India in analyzing the common variables among the major variables related to Korean companies' entry strategy into India. To measure efficiency, 'DEAR 2.1' An output - oriented CCR model and BBC model were used for the analysis to minimize the input and maximize the output factor. The results of the study on the relative efficiency analysis of the investment strategy of the companies in India are as follows. First, six firm was analyzed efficiently in the CCR model and most firms showed inefficiency in management. Second, even with the BCC model, which represents pure technology efficiency, 103 companies were analyzed efficiently as well. Unlike the CCR, overall technology efficiency of firms was high. Third, as a result of analyzing the efficiency of the scale, it was found that six company showed efficient efficiency, and most of the companies showed inefficiency overall. Companies with inefficiencies should increase efficiency by expanding their scale. Based on the above analysis, it is expected that the companies that will enter India in the future should secure the human and material resources to realize economies of scale considering the number of employees, investment scale, investment type and industry.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.17-22
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• 2010

The aim of this study is to research applicable possibility of DSI (Dry Sorbent Injection) technique in $SO_2$ removal process using lab-scale facility based on 500MW in capacity coal-fired thermal power plant operated by South Korea N. Power Co., Ltd. To increase the $SO_2$ removal efficiency, it is considered the mixing enhancement as different shapes called lobed-plate and stepplate tested ultimately for optimum shape. Also it tested to analysis $SO_2$ removal efficiency by numbers of injection holes. At experimental it showed the $SO_2$ removal efficiency is higher using mixing enhancement than not installed mixing enhancement and case on the step-plate was shown the most $SO_2$ removal efficiency. Also, $SO_2$ removal efficiency was higher recording which will increase the injection holes case on not installed mixing enhancement. But, the $SO_2$ removal efficiency was higher 4 injection holes case on installed mixing enhancement.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.2
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• pp.64-71
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• 2016

Recently, nanotechnology has grown as one of the leading science technology along with other converging technologies such as biology, information, medicine etc., bringing the continuous investment of the government in nano-related field. However, it is difficult to measure and evaluate the performance of the national research and development programs because of the multidimensional character of the expected outcomes. This study aims to measuring efficiency of the national nanotechnology research and development programs using DEA model. The decision making units are nine nano-related ministries including the Ministry of Science, ICT and Future Planning. The input variables are total expenditure, number of the programs and average expenditure per program. The output variables are science, technology and economic indicator, and the combination of these outputs are respectively measured as seven different DEA cases. The Ministry of Science, ICT and Future was the first efficient ministry in total technical efficiency. Ministry of Agriculture, Food and Rural Affairs and the Ministry of Food and Drug Safety were efficient in pure technical efficiency, when the Ministry of Commerce Industry and Energy took the first in the scale efficiency. The program efficiency was affected by organizational characteristics such as the institution's scale, the concentration of the research paper or the patent, technology transfer or the commercialization. The result of this study could be utilized in development of the policy in the nanotechnology and the related field. Furthermore, it could be applied for the modification of expenditure management or the adjustment of the research and development programs' input and output scale for each ministry.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.33-42
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• 2010

The purpose of this study was to understand the degree of natural radon removal efficiency of small-scale water supply systems. Six sites were selected for this study, and data on well characteristics (depth, pumping rate, water tank capacity, distance from well to tap water) were obtained. Water samples both from raw water and three tap waters at each site were collected and analyzed for radon concentration. Average radon removal efficiency of the five sites (A-E) in Nov. 2006 was 26.0% while that of the same sites in Dec. 2006 was 45.6% indicating seasonal difference in natural radon removal efficiency. Meanwhile short-term (April 23, April 30, May 8, 2007) radon removal efficiency from the site F was 44.1-49.0%, implying only a little difference in natural radon removal efficiency. The degree of radon removal at tap water was influenced mainly by pumping rate rather than distance from the well and water tank capacity.

• Asia pacific journal of information systems
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• v.12 no.3
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• pp.1-20
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• 2002

For the last decade, some leading groups of corporations in Korea have integrated and managed their Information Systems(IS) functions. Each group established a separate System Management(SM) company to manage the IS and tried to get a synergy effect from the integration. These attempts, however, were not initiated by any one company. Rather they were group efforts. Moreover, the previous measuring tools evaluated IS with the scope of technical performance or quantitative user satisfaction using an absolute scale. Obscure criteria were used in an attempt to present improvements in IS function which were qualitatively weak. This study evaluates whether integration has been efficient and successful. For this purpose, we evaluate the performance efficiency of IS functions with Data Envelopment Analysis(DEA) methodology. In comparison with prior methods, DEA presents the rate of relative efficiency, the efficiency frontier for improving inefficiency, the degree of improvement(slack), and the guideline to construct any benchmark(reference set). For our DEA evaluation, this study selected a leading group of 23 companies in Korea. Our experimental results are as follows. First, efficiency was rated low on average. It also demonstrates that the motivation of performance efficiency of IS functions is deficient. Second, the result of the test to find the existence of economy of scale and scope shows that the growth of an organization and industrial characteristics do not affect IS performance efficiency from the perspective of user satisfaction. Finally, the comparison with other evaluation approaches informs us that DEA can be a complementary evaluation method which supports other measuring tools.

• The Journal of the Korea Contents Association
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• v.8 no.5
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• pp.192-206
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• 2008

With many changes such as the increase in telemarketing, internet marketing and enforcement of bancassurance, the Korean life insurance companies have undergone a startling transformation. The purpose of this paper is to measure and analyse the static/dynamic efficiency of Korean life insurance companies employing Data Envelopment Analysis(DEA). As the result of the static efficiency analysis, we provide CCR, BCC and scale efficiency, return to scale, and reference set of Korean life insurance companies in 2004. And we also describe about the trend and stability of their efficiency for 7 years(1998-2004) in the dynamic efficiency analysis.