• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2227-2232
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• 2003

For a reasonable analysis of grade efficiency of cyclone separator, in-line measurements of particle size and particle concentration are needed. The purpose of this study is to define the correlation of measurement data and to measure grade efficiency and pressure drop. The authors adapted that the grade efficiency could be calculated directly from the counted particle numbers. The problem of collection efficiency calculation was different from counting rate of aerosol counters under the same conditions. It is important factor to use the rate of the particle counters to obtain reliable results. Therefore, the authors should use and calculate compensation factor considering sensitivity of aerosol counters, gas velocity and concentration affect higher 30% than originally measured grade efficiency. As the pressure drop and grade efficiency increase, as flow rate increase and then also pressure drop and grade efficiency increase.

• 품질경영학회지
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• 제38권3호
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• pp.393-407
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• 2010

The purpose of this study is to analysis relative efficiency and efficiency in process of time. Thus we use panel data of 34 local public medical centers between 2003 and 2005 to use DEA and Malmquist analysis. The result of our this study is as flow; first, The results of static efficiency of 34 local public medical centers show 10 CCR model and 23 BCC model which is difference of efficiency by economic of scale. Second, a cause of increased efficiency is not only change of technology but also change of efficiency to management system index show between 2003 and 2005 by Malmquist analysis and contracting-out is higher than direct management between 2004 and 2005. That means efficiency of local public medical centers is their own effort and innovation not government subsidies.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2003년도 학술발표회논문집(1)
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• pp.62-65
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• 2003

Improvement of the efficiency of the agricultural water use is important for the sustainable water management because the agricultural water use occupied above 60% of the total water use in korea. For the analysis of agricultural water use the Yi-dong experimental site was selected. For the monitoring system of the experimental site, four rainfall gauging stations and twenty-six water level gauging stations are established and operated. Analyses of the measured data are processed for the irrigation efficiency of agricultural water on the eight irrigation areas.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.895-904
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• 2021

This study aims to investigate the impact of innovation on firm efficiency. Panel data of fourteen finance companies and nine technology companies from 2011 to 2019 on the Vietnam Stock Exchange Market is derived from audited financial statements, annual reports, and other crucial reports that are provided by Vietstock; macroeconomic variables are collected from the World Bank Database. A two-stage approach is used. First, use of the Data Envelopment Analysis methodology to measure firm efficiency. Second, use of the Pooled ordinary least squares, the Fixed effects model, and the Random effects model to investigate the impact of innovation on firm efficiency. Furthermore, the Generalized Method of Moments and the Tobit model are used to validate the impact of innovation on firm efficiency, and the t-test is used to confirm the difference in efficiency with and without the impact of innovation between two industries. The results show that there is a significant impact of innovation on efficiency, and innovation plays a more important in increasing the efficiency of the finance industry than the technology industry. Moreover, the relation between age and efficiency is like the U-shaped, and between size and efficiency is like the inverted U-shaped, whereas efficiency is not associated with inflation.

• Asian-Australasian Journal of Animal Sciences
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• 제16권9호
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• pp.1390-1396
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• 2003

This research investigates the use of crossbreed cattle (Red Sindhi${\times}$Yellow Local cattle) at household level in the lowland and mountainous zones in Quang Ngai province, Vietnam. The internal and external inputs and outputs of mixed farming systems were analysed to quantify the productivity and efficiency of the use of the crossbred and yellow local cattle. In the mountainous zone, households with crossbred cattle had a lower crop and farm efficiency rate than households without crossbred cattle, but in terms of crop, livestock and farm productivity they did not differ. In the lowland zone, households with crossbred cattle had a higher crop, livestock and farm productivity and crop efficiency rate than households without crossbred cattle, but did not differ in terms of farm efficiency rate. The lowland zone had higher off-farm income, crop and household productivity, but lower livestock productivity, livestock and farm efficiency rate than the mountainous zone. Households with crossbred cattle had lower off-farm income than households without crossbred cattle. The results suggest that interactions between zone and kind of household occur at the households and show that the yellow local cattle is a better breed in the mountainous zone and more or less comparable with crossbred cattle in the lowland zone. The extrapolation of the use of crossbred cattle should be carefully considered in line with feeding practice and management.

• 한국물환경학회지
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• 제36권5호
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• pp.405-422
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• 2020

Land use change by urbanization has significantly affected the hydrological process including the runoff characteristics. Due to this situation, it has been becoming more complicated to manage non-point source pollutions caused by rainfall. In order to effectively control non-point sources, it is necessary to identify the reduction efficiency of the various management method based on land use characteristics. Thus, the purpose of this study is to analyze the reduction efficiency of non-point source pollution management practices targeting three different watersheds with the different land use characteristics using the Soil and Water Assessment Tool (SWAT). To do this, the vulnerable subwatersheds to non-point source pollution occurrence within each watershed were selected based on the streamflow and water quality simulation results. Then, considering the land use, low impact development (LID) or best management practices (BMPs) were applied to the selected subwatersheds and the efficiency of each management was analyzed. As a result of analysis of the non-point source pollution reduction efficiency, when LID was applied to urban areas, the average reduction efficiencies of SS, NO₃-N, and TP were 5.92%, 4.62%, and 10.35%, respectively. When BMPs were applied to rural areas, the average reduction efficiencies of SS, TN and TP were 35.45%, 4.37%, and 10.16%, respectively. The results of this study can be used as a reference for determining appropriate management methods for non-point source pollution in urban, rural, and complex watersheds.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.255-258
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• 2003

Agricultural water use occupies 60% of the total water use in Korea, so variation of the farming pattern and the efficiency of agricultural water use is important for the sustainable water management. For the analysis of agricultural water use, the Yi-dong experimental site was selected. For the monitoring system of the experimental site, four rainfall gauging stations and twenty-six water level gauging stations are established and operated. Analyses of the measured data are processed for the irrigation efficiency of agricultural water and the effect of the variation of farming pattern.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제16권2호
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• pp.137-154
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• 2012

Comparative studies on mathematical modeling cognition feature were carried out between 15 excellent high school third-grade science students (excellent students for short) and 15 normal ones (normal students for short) in China by utilizing protocol analysis and expert-novice comparison methods and our conclusions have been drawn as below. 1. In the style, span and method of mathematical modeling problem representation, both excellent and normal students adopted symbolic and methodological representation style. However, excellent students use mechanical representation style more often. Excellent students tend to utilize multiple-representation while normal students tend to utilize simplicity representation. Excellent students incline to make use of circular representation while normal students incline to make use of one-way representation. 2. In mathematical modeling strategy use, excellent students tend to tend to use equilibrium assumption strategy while normal students tend to use accurate assumption strategy. Excellent students tend to use sample analog construction strategy while normal students tend to use real-time generation construction strategy. Excellent students tend to use immediate self-monitoring strategy while normal students tend to use review-monitoring strategy. Excellent students tend to use theoretical deduction and intuitive judgment testing strategy while normal students tend to use data testing strategy. Excellent students tend to use assumption adjustment and modeling adjustment strategy while normal students tend to use model solving adjustment strategy. 3. In the thinking, result and efficiency of mathematical modeling, excellent students give brief oral presentations of mathematical modeling, express themselves more logically, analyze problems deeply and thoroughly, have multiple, quick and flexible thinking and the utilization of mathematical modeling method is shown by inspiring inquiry, more correct results and high thinking efficiency while normal students give complicated protocol material, express themselves illogically, analyze problems superficially and obscurely, have simple, slow and rigid thinking and the utilization of mathematical modeling method is shown by blind inquiry, more fixed and inaccurate thinking and low thinking efficiency.

• 한국토양비료학회지
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• 제30권4호
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• pp.309-313
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• 1997

벼 건답직파 재배시 볏짚 시용과 질소 분시에 따른 벼 질소 흡수 양상을 검토하고자 호남평야지인 전북통에서 동진벼를 공시하여 포장 시험한 결과를 요약하면 다음과 같다. 1. 건답기간중 토양질소의 변화 양상을 보면 요소태질소는 파종후 7일이후에는 검출되지 않았으나, $NH_4-N$는 파종후 7일, $NO_3-N$는 파종후 25일에 최대값을 나타냈다. 2. 토양 깊이 70cm에서 채취된 토양 용액중 $NO_3-N$의 농도는 질소분시가 적은 기비중점인 구에서 파종후 생육초기에 감소되는 양이 많았으며, 볏짚을 처리함 으로써 표토로부터 심토로 이동되는 양을 감소시킬수 있었다. 3. 수확기 질소흡수량은 볏짚시용시 질소3회 분시구에서 가장 많았으며, 시비질소에 의한 질소이용률은 20%였으나, 볏짚 시용으로 27%까지 향상 시킬수 있었다. 4. 질소 분시에 따른 수량은 관행 5070 kg/ha, 질소 전량 기비구 4970 kg/ha, 2회 분시구 5110 kg/ha, 3회 분시구 5150 kg/ha로 관행에 비하여 근소한 차이로 증가 되었다.

• Journal of Crop Science and Biotechnology
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• 제10권2호
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• pp.57-63
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• 2007

Due to the strong influence of nitrogen(N) on plant productivity, a vast amount of N fertilizers is used to maximize crop yield. Over-use of N fertilizers leads to severe pollution of the environment, especially the aquatic ecosystem, as well as reducing farmer's income. Growing of N-efficient cultivars is an important prerequisite for integrated nutrient management strategies in both low- and high-input agriculture. Taking maize as a sample crop, this paper reviews the response of plants to low N stress, the physiological processes which may control N-use efficiency in low-N input conditions, and the genetic and molecular biological aspects of N-use efficiency. Since the harvest index(HI) of modern cultivars is quite high, further improvement of these cultivars to adapt to low N soils should aim to increase their capacity to accumulate N at low N levels. To achieve this goal, establishment and maintenance of a large root system during the growth period may be essential. To reduce the cost of N and carbon for root growth, a strong response of lateral root growth to nitrate-rich patches may be desired. Furthermore, a large proportion of N accumulated in roots at early growth stages should be remobilized for grain growth in the late filling stage to increase N-utilization efficiency. Some QTLs and genes related to maize yield as well as root traits have been identified. However, their significance in improving maize NUE at low N inputs in the field need to be elucidated.