• Journal of Mechanical Science and Technology
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• 제15권5호
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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.

• 수산경영론집
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• 제26권2호
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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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• 제9권2호
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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.

• 한국환경과학회지
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• 제11권10호
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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.

• 통상정보연구
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• 제19권3호
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• pp.45-61
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• 2017

본 연구에서는 한국기업의 인도 진출 전략의 효율성을 DEA 모형을 통해 측정하고, 도출된 결과로 현재 인도 진출 한국기업의 현황과 경쟁력을 살펴보고자 하였다. 본 연구에서는 인도 진출 한국기업 진출 전략에 관한 주요 변수 중 공통된 변수를 분석에 사용함에 있어서 인도에 진출한 112개 기업을 대상으로 본 분석을 실시하였으며, 효율성 측정을 위하여 'DEAR 2.1' 프로그램을 이용하여 투입량은 최소로 유지하고 산출요소를 극대화하는 산출지향 CCR모형과 산출지향 BBC모형을 분석에 이용하였다. 인도에 진출한 기업의 대한 투자전략에 대한 상대적 효율성 분석에 관한 연구결과는 다음과 같다. 첫째, CCR 모형에서 효율적으로 분석된 기업은 6개 기업으로 나타났으며, 대부분의 기업이 경영의 비효율성을 보이고 있다. 둘째, 순수기술의 효율성을 나타내는 BCC 모형에서 효율적으로 분석된 기업은 103개 기업으로 나타났으며 CCR과 달리 전반적으로 기업의 순수기술효율성이 높게 나타났다. 셋째, 규모의 효율성을 분석한 결과 효율적으로 나타난 기업은 6개 기업으로 나타났으며 전반적으로 대부분의 기업이 비효율성을 보이고 있는 것으로 나타났으며, 비효율성을 갖는 기업은 모두 규모를 확대해 효율성을 개선하여야 한다. 위와 같은 분석 결과를 토대로 했을 때 향후 인도에 진출할 기업은 종업원 수, 투자규모, 투자형태, 업종을 고려하여 규모의 경제를 실현할 수 있는 인적 물적 자원을 확보하여야 할 것으로 예상된다.

• 대한환경공학회지
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• 제32권1호
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• pp.17-22
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• 2010

본 연구의 목적은 대형 석탄 화력 발전소에 DSI (Dry Sorbent Injection)공정을 실제 적용 할 경우에 실현 가능성에 대한 연구로서 N 발전(주)의 S 화력발전본부에서 운용중인 500MW급 석탄화력 발전시설의 보일러 후단에서 전기 집진기 전 단까지를 모델로 삼아 Lab-scale 실험장치를 제작하여 탈황효율을 높이기 위한 실험을 수행하였다. 이를 위하여 Lobedplate와 Step-plate라는 혼합촉진장치를 고안하고 각각 형상을 달리하여 궁극적으로 탈황효율을 높이기 위한 혼합촉진장치의 최적 형상도출을 위한 실험을 수행하였으며 부수적으로 탈황제의 분사구의 개수에 따른 탈황효율 또한 분석하였다. 그 결과 혼합촉진장치가 설치된 경우가 더 높은 탈황 효율을 나타내었고 형상에서는 계단형상일 경우 가장 높은 탈황효율을 보였다. 또한, 탈황제의 분사구의 개수에 따른 탈황효율은 혼합 촉진 장치가 설치되지 않은 경우, 분사구의 개수가 증가할수록 높은 탈황 효율을 보였으나 혼합촉진장치가 설치된 경우는 분사구의 개수가 4개일 경우가 이론적 결과와 같이 가장 높은 탈황효율을 나타내었다.

• 산업경영시스템학회지
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• 제39권2호
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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.

• 자원환경지질
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• 제43권1호
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• pp.33-42
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• 2010

마을상수도 지하수의 라돈의 자연저감 정도를 파악하기 위하여 6개 지점을 대상으로 지하수공의 제원, 저수조의 크기, 지하수 사용량, 원수로부터 꼭지수까지의 거리를 측정하고 원수와 3개 꼭지수의 라돈함량을 분석하고 비교하였다. 5개 마을상수도 지하수(A-E)에서 2회에 걸친 원수와 꼭지수의 라돈 자연저감은 2006년 11월에는 26.0%, 2006년 12월에는 45.6%로 나타나 계절별 지하수 사용량에 따른 자연저감율에 차이가 있는 것으로 나타났다. 그러나 마을상수도 F에서 2007년 4월 일주일 간격으로 3회 분석된 꼭지수의 라돈함량은 원수의 44.1-49.0%로 나타나 단기간에 걸친 라돈 자연저감에는 큰 변화가 없는 것으로 나타났다. 한편 꼭지수에서의 라돈의 저감은 원수로부터의 거리, 저수조의 크기보다는 지하수의 사용량에 더 영향을 받는 것으로 나타났다.

• Asia pacific journal of information systems
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• 제12권3호
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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.

• 한국콘텐츠학회논문지
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• 제8권5호
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• pp.192-206
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• 2008

우리나라의 생명보험산업은 IMF 사태와 방카슈랑스의 도입 등 많은 변화를 겪어왔으며 앞으로 시행될 자본통합법의 시행도 추후에는 생명보험산업에 많은 영향을 미칠 것으로 보이며 생명보험회사의 경쟁력 강화를 위해서는 효율성의 분석이 필수적이다. 본 논문은 DEA 모형을 이용하여 우리나라에서 영업 중인 생명보험회사들의 효율성을 분석했다. 이를 위해 투입변수는 두 가지 범주로 나누어서 분석을 시도하였고 동태적 효율성을 분석하기 위해서 DEA/WINDOW 모형을 도입하였다. 이를 통하여 생명보험회사들의 CCR, BCC, 규모효율성을 알 수 있었고 7년간(1998년$\sim$2004년)의 효율성의 추세와 안정성을 파악할 수 있었다.