• 농촌계획
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• 제25권4호
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• pp.27-33
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• 2019

Agricultural water for crops are faced with the need to improve the use efficiency due to the impact of climate change. Water productivity (WP) is known as a good indicator for assessing resources efficiency. This study was conducted to assess WP of rice and potential water consumption (PWC) as new indicator for water use efficiency assessment. The average of WP was 0.7 kg/㎥, and Jeonbuk had the highest WP as 0.83 kg/㎥. Kangwon and Kyungbuk had the lowest WP as 0.59 kg/㎥. PWC showed the same trend because of rice consumption per capita, but Total PWC considering population living in each province showed the different trend with PWC. Every year, the changing patterns of WP was increasing little by little, and the patterns of PWC was decreasing greatly than WP. These results mean that WP has been slowly improved through breed development and irrigation techniques, and PWC was affected by reduced rice consumption and WP increasing. PWC could also be useful as an indicator to compare the water use efficiency between provinces or nations.

• International Journal of Precision Engineering and Manufacturing
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• 제1권1호
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• pp.5-14
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• 2000

In the design of epicyclic gearing, the analysis of interference and mechanical efficiency is an important index. As an applied way, epicyclic gearing can be used for planetary gear drive and differential gear unit. In case that one of its components is fixed with intend, it is called planetary gear drive. On the contrary, in case that no component is fixed, it is called differential gear unit. In this paper, various design constraints and interferences are defined for 2K-H I type epicyclic gearing which is a basic arrangement of diverse epicyclic gearings. And various interferences are analyzed, and mechanical efficiency is calculated in case that 2K-H I epicyclic gearing is used for a differential gear unit as the change of gear ratio, cutter pressure angle, addendum modification coefficient. As that results, trend of mechanical efficiency is investigated in the ranges of addendum modification coefficients which would not lead to interferences, and the optimal range of addendum modification coefficient which can generate the maximum mechanical efficiency are presented. In order to prove results of theoretical efficiency analysis, experimental studies are performed.

• 한국추진공학회지
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• 제3권3호
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• pp.1-8
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• 1999

$H_2$O/Kerosene을 사용하여 Unlike 충돌형 인젝터(FOOF형)에서 산화제와 연료의 운동량비 변화에 따른 혼합효율을 측정하였다. 모의 추진제의 운동량비 1.5(총혼합비 1.89)에서 혼합성능은 최대 값을 나타내었으며 모의 추진제의 실험결과는 실제 추진제인 LOX/Kerosene에 적용하여 혼합특성속도 효율을 예측하였다 연구 결과 혼합특성속도 효율은 운동량비 2.0에서 최대 값을 나타내었다. 이러한 예측은 실제 연소실험을 통하여 얻어진 연소효율과 약간의 차이는 있으나 초기설계자료로서 충분한 가치가 있는 것으로 판단된다.

• 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.

• 기술혁신연구
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• 제16권2호
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• pp.41-63
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• 2008

Employing firm-level data during the period of 1980-2006, this paper analyzes the R&D efficiency of IT SMEs. We focus on comparing the R&D efficiency of IT SMEs with that of large-sized IT firms and non-IT SMEs. The results are summarized as follows. First, the R&D investment of IT SMEs has not been increased since 2000. In IT manufacturing industry, the portion of the R&D investment of IT SMEs is no more than 10.6% in 2005. Second, we analyze the innovation capacity of SMEs with the number of the patent application. The result is similar with the trend of R&D investment. The portion of the patent application of SMEs has not been increased since 2000. Third, the R&D efficiency of non-IT firms is higher than that of IT SMEs regardless of the firm size. The R&D efficiency of non-IT SMEs is over three times as large as that of IT SMEs. Meanwhile, The R&D efficiency of the large-sized non IT firms is 1.86 times as large as that of IT large-sized firms. Finally, we estimate the R&D elasticity and compare between IT manufacturing and service industry. The result shows that the R&D elasticity of IT service industry is higher than that of IT manufacturing industry, regardless of firm size.

• KEPCO Journal on Electric Power and Energy
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• 제2권2호
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• pp.193-203
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• 2016

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.613-618
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• 2011

More than 7 million persons use Seoul Metropolitan Subways (SMS) everyday and the number has been in increasing trend. With the increasing trend of concerns on indoor air quality(IAQ), the management of IAQ has become an important issue, especially in case of subway operators, because most of subway lines are placed underground with poor ventilation condition. The ultimate object of study develop independent cleaning device that reduce efficient fine particle and $CO_2$. Urban subway has characteristics about proper clean air flow, must be installed in narrow space and maintenance cycle has enough time. Two layered electrically pre-charged filters were used for removing particulate matters and gas absorbers are packed between two layer filters for removing gases pollutants such $CO_2$, VOCs and HCHO. Urban subway has characteristics about proper clean air flow, must be installed in narrow space and maintenance cycle has enough time. SCAP prototype is producted as all in one method which decrease fine dust, $CO_2$ and noxious gas. and basic test carry out with quantity of wind, a gap of pressure, sampling efficiency.

• 보건행정학회지
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• 제23권1호
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• pp.78-89
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• 2013

This study empirically analyze efficiency and productivity changes of public hospitals of Korea using data envelopment analysis/Window model and global Malmquist indices model. We use the ten-year data from 2001 to 2010 of 30 regional public hospitals listed database from the Association of Korean Regional Public Hospitals. The main focuses are to reveal whether the technical inefficiency are improved as time goes by, and efficiency and productivity are affected by environmental factors. The results can be summarized as follows. First, the efficiencies of public hospitals rise in trend as time passes. Second, regional public hospitals show the different average efficiencies according to their regional type, hospital type, operational type, medicaid type, and demand and supply conditions by Mann-Whitney U-tests. Third, technical efficiency changes mainly contribute to 4.4% annual average growth rate of productivity of regional public hospitals during that period. Our findings have some policy implications. It is confirmed that there exist some environmental inefficiencies, and those inefficiencies can not be overcome through just improving the inner management system. Thus, policy and institutional changes are necessary for regional public hospitals to improve efficiency and productivity overall.

• Journal of Biosystems Engineering
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• 제40권2호
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• pp.137-144
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• 2015

Purpose: The high energy requirement of extraction of oil from jatropha seed and reduction of loss in oil content between whole seed and kernel of jatropha necessitate seed shelling. The purpose of this study is to develop and evaluate the performance of a jatropha seed shelling machine based on seed moisture content. Methods: A shelling machine was designed and constructed for jatropha seed. The components are frame, hopper, shelling chamber, concave, and blower with discharge units. The performance evaluation of the machine was carried out by determining parameters such as percentage of whole kernel recovered, percentage of broken kernel recovered, percentage of partially shelled seed, percentage of unshelled seed, machine capacity, machine efficiency, and shelling efficiency. All of the parameters were evaluated at five different moisture levels: 8.00%, 9.37%, 10.77%, 12.21%, and 13.68% w.b.). Results: The shelling efficiency of the machine increased with increase in seed moisture content; the percentage of whole kernel recovered and percentage of partially shelled seed decreased with increase in moisture content; and percentage of broken kernel, machine efficiency, and percentage of unshelled seed followed a sinusoidal trend with moisture content variation. Conclusion: The best operating condition for the shelling machine was at a moisture content of 8.00% w.b., at which the maximum percentage of whole kernel recovered was 23.23% at a shelling efficiency of 73.95%.

• 한국콘텐츠학회논문지
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• 제8권8호
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• pp.147-157
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• 2008

ERP는 많은 기업에서 전략적인 경쟁우위를 위해 도입하고 있는 산업정보시스템의 일반적인 유형이다. 본 연구의 목적인 DEA기법을 통해 ERP시스템을 도입한 국내기업의 경영효율성을 분석함으로써 비효율적인 기업의 투사값과 벤치마킹의 대상이 될 수 있는 기업들의 참조집합을 제시하고자 한다. 총 38개 ERP 시스템을 도입한 기업들의 CCR, BCC 효율성과 규모수익성(RTS)을 평가하였다. 분석결과 CCR효율성이 1인 업체는 3개 기업, BCC효율성이 1인 업체는 7개 기업으로 분석되었다. 규모수익성은 IRS가 22개의 기업, DRS가 2개의 기업, CRS가 4개의 기업으로 분석되었다.