• 한국프랜차이즈경영연구
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• 제3권1호
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• pp.130-143
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• 2012

Franchise store retailing is taking on ever greater roles in business and commerce in China. The diverse product range, small-batch order, high frequency and time-specific requirements inherent in retail logistics make it the most complicated of all categories of logistics. In franchise store retailing, expanding business scales make trans-regional development a trend. Without a well-functioning logistic system, the standardized delivery of products would be held back, impacting trans-regional development strategy and operational costs. Therefore, the efficiency of franchise store retailing largely depends on logistical efficiency. The integrated and streamlined management of franchise stores depends in large measure on their logistical centers. As such, logistical centers constitute the key link and bears on core competitiveness in franchise store retailing. This thesis begins with an analysis of the current developments and four basic logistical models of franchise store retailing in China, proceeds to summarize developmental trends as well as focal issues and proposes an efficiency enhancing plan.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.402-407
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• 2003

The main reason to select the maxium plant efficiency through the performance test in fossil power plant is to increase the efficiency of power plant as well as saving energy collated with the policy of government. This study is aimed at unerstanding the variantion trend of efficiency and analyzing the efficiency of boiler and turbine through each of the performance test. Ultimately, the maxium efficiency of power plant will be presented in super-critical pressure type power plant.

• Molecules and Cells
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• 제37권8호
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• pp.575-584
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• 2014

Potassium is a macronutrient that is crucial for healthy plant growth. Potassium availability, however, is often limited in agricultural fields and thus crop yields and quality are reduced. Therefore, improving the efficiency of potassium uptake and transport, as well as its utilization, in plants is important for agricultural sustainability. This review summarizes the current knowledge on the molecular mechanisms involved in potassium uptake and transport in plants, and the molecular response of plants to different levels of potassium availability. Based on this information, four strategies for improving potassium use efficiency in plants are proposed; 1) increased root volume, 2) increasing efficiency of potassium uptake from the soil and translocation in planta, 3) increasing mobility of potassium in soil, and 4) molecular breeding new varieties with greater potassium efficiency through marker assisted selection which will require identification and utilization of potassium associated quantitative trait loci.

• 지질공학
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• 제29권4호
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• pp.509-529
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• 2019

본 연구는 강변여과수 취수를 위한 충적우물에서의 필터재의 역할과 이중필터 취수정의 적용성 및 개선효과를 평가할 목적으로 수행하였다. 토층으로 이루어진 하천변의 자유면대수층에서 필터 조건을 달리 하여 실규모의 이중필터 취수정과 단일필터 취수정을 각각 설치하고 설치된 우물에서 대수성 시험을 실시하여 필터재 조건에 따른 수위강하특성, 투수특성, 적정 양수량 및 우물 효율을 평가하였다. 결과적으로, 이중필터층을 형성시켜 주는 것은 대수층과 필터층의 경계부에서 지하수 유동의 완충작용을 하여 유입되는 지하수의 급격한 속도변화를 최소화하는 효과를 나타내는 것으로 추정된다. 이는 난류 발생을 최대한 억제하여 보다 넓은 범위의 지하수를 효과적으로 취수정 내부로 유입시키는 역할을 하고 이로 인하여 취수량이 단일필터 취수정에 비해 높음에도 불구하고 주변 지하수위의 변화를 줄일 수 있는 것으로 보인다. 또한, 이중필터의 설치만으로도 기존 시스템(단일필터 취수정) 대비 투수성, 적정 양수량, 우물 효율이 개선됨을 시험을 통해 확인할 수 있었다. 본 연구의 결과는 앞서 수행한 다양한 연구와 종합하여 충적대수층에서의 이중필터 취수정 우물의 설계 및 시공에 대한 표준화된 기준을 마련하는데 활용할 계획이다. 또한, 강변여과수에 주로 적용되고 있는 단일 필터 취수정 및 방사상집수정과 대비하여 이중필터 취수정 적용 효과에 대한 객관적 입증 자료로의 활용이 기대된다.

• International Journal of Fluid Machinery and Systems
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• 제9권3호
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• pp.256-264
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• 2016

To meet the demand of higher handling capacity, a mixed-flow submersible deep well pump was designed and tested. The main hydraulic components are made of plastics, which is free of erosion, light-weight, and environment-friendly. To simplify plastic molding process, and to improve productivity, an axial-radial guide vane was proposed. To clarify its effect on the performance, a radial guide vane and a space guide vane are developed as well. By comparison, the efficiency of the pump equipped with the axial-radial guide vane is higher than the radial guide vane and is lower than the space guide vane, and its high efficiency range is wide. The static pressure recovery of the axial guide vane is a bit lower than the space guide vane, but it is much larger than the radial guide vane. Taking the cost and molding complexity into consideration, the axial-radial guide vane is much economic, promoting its popularity for the moderate and high specific speed submersible deep well pumps.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.468-472
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• 1997

The effect of the surface state on the quantum efficiency of underlying GaAs/AlGaAs multi-quantum well(MQW) structures consisting of three GaAs quantum wells with different thickness, is studied by low temperature photoluminescence(PL). The structure was grown by molecular beam epitaxy(MBE) on (100) GaAs substrate. The thickness of three GaAs quantum wells was 3, 6 and 9 nm, respectively. The MQWs were placed apart from 50 nm AlGaAs edge-barriers including two inner-barriers with 15 nm in thickness. The samples used in this study were prepared with different growth temperatures. Particularly, the hydrogen passivation effect to the 9 nm quantum well located at near surface appeared much stronger than any others. Transition energy and optical gain related to the hydrogen passivation effects on the multi-quantum well structure was calculated by transfer matrix method.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.608-611
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• 2004

건설 프로세스에서 효율성은 프로젝트의 성패를 좌우하는 중요한 요인 중의 하나이다. 하지만 기존의 생산성 향상 방안들은 1인당 매출과 같이 단순히 결과 위주의 지표를 중심으로 프로젝트를 관리함으로써 많은 변화 요인을 가지고 있는 건설 산업을 특성을 반영하는데 한계를 가지고 있으며, 특히 다수의 참여자에 의해 여러 단계로 진행되는 건설 프로젝트의 Life cycle 상에서 각 공종별 생산성 측정 및 관리, 그리고 생산성 저하의 원인을 도출하는데 한계를 가지고 있다. 따라서 본 연구는 결과 위주의 성과측정 방법인 생산성 개념을 보완하기 위해 프로젝트의 Life cycle의 각 단계별 정성적 평가를 포함하는 건설 효율성 개념을 제안하고 이를 측정하는 방법론을 제시하였으며, 초고층 빌딩의 커튼월 프로세스를 대상으로 제안한 모델을 적용하져다.

• The Journal of Asian Finance, Economics and Business
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• 제5권4호
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• pp.73-83
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• 2018

The purpose of this paper is to examine the relationship between regional financial development and corporate investment efficiency as well as the relationship between firm-level characteristics and corporate investment efficiency. Using a large sample of A-listed companies in China from CSMAR database between 2003 and 2016, this paper explores corporate investment efficiency and its influencing factors in emerging market on the basis of heterogeneous stochastic frontier model. The results show that: (1) the average investment efficiency of Chinese listed companies is 74.5%, and the investment efficiency of large enterprises, state-owned enterprises and enterprises with relatively high financial development level is significantly higher; (2) compared with average corporate investment efficiency in the year 2003, the investment efficiency of different types of enterprises in 2016 is significantly higher, and the gap is gradually widening; (3) enterprise heterogeneity namely firm size, nature of property right, and institutional environment reflected by the level of regional financial development indirectly affects corporate investment efficiency by influencing the financing constraints and uncertainty. The findings suggest that to improve corporate investment efficiency in emerging market, financial market should be accelerated, regional balance should be restored and the differences among regions, industries and differences between public and private sectors should be eliminated.

• Journal of the Korean Statistical Society
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• 제31권2호
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• pp.251-259
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• 2002

Lagged regressor models with general stationary errors independent of the regressors are considered. The regressor process is unstable having characteristic roots on the unit circle. If the order of the lag matches the number of roots on the unit circle, the ordinary least squares estimator (OLSE) is asymptotically efficient in that it has the same limiting distribution as the generalized least squares estimator (GLSE) under the same normalization. This result extends the well-known result of Grenander and Rosenblatt (1957) for asymptotic efficiency of the OLSE in deterministic polynomial and/or trigonometric regressor models to a class of models with stochastic regressors.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.351-354
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• 2003

This study was carried out to set up design criteria of Eryngii cultivation houses. Optimization of lay-out efficiency together with analysis of structural safety were two main tools of approaching toward reasonable models to be developed. Some models tentatively assumed according to the result of field survey and analysis were compared in the aspect of structural safety as well as energy efficiency.