• 한국진공학회:학술대회논문집
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• 한국진공학회 2004년도 제26회 학술발표회 초록집
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• pp.88-88
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• 2004

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 IUMRS-ICEM ABSTRACT BOOK
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• pp.147.4-147
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• 1998

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제16회 학술발표회 논문개요집
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• pp.121-121
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• 1998

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.1319-1327
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• 2015

As wind power farm (WPF) installations continue to grow, monitoring and controlling large-scale WPFs presents new challenges. In this paper, a hierarchical network architecture is proposed in order to provide remote monitoring and control of large-scale WPFs. The network architecture consists of three levels, including the WPF comprised of wind turbines and meteorological towers, local control center (LCC) responsible for remote monitoring and control of wind turbines, and a central control center (CCC) that offers data collection and aggregation of many WPFs. Different scenarios are considered in order to evaluate the performance of the WPF communications network with its hierarchical architecture. The communications network within the WPF is regarded as the local area network (LAN) while the communication among the LCCs and the CCC happens through a wide area network (WAN). We develop a communications network model based on an OPNET modeler, and the network performance is evaluated with respect to the link bandwidth and the end-to-end delay measured for various applications. As a result, this work contributes to the design of communications networks for large-scale WPFs.

• 한국유기농업학회지
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• 제22권1호
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• pp.1-23
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• 2014

The purpose of this paper was to measure technical efficiencies and scale efficiencies of Korean seed industry by DEA method, and to identify the factors affecting the efficiencies by Tobit regression model. Survey data of 50 seed companies nationwide were applied for the analysis. The average score of overall technical efficiency for the surveyed companies in 2012 was 0.44, which is decomposed into pure technical efficiency 0.68 and scale efficiency 0.63. A majority of the seed companies exhibited at least one form of inefficiency except a few companies in optimal scale. It was also shown the most companies were operating in the stage of increasing returns to scale, which implies Korean seed companies are mainly in smaller scale than optimal. Additional results suggest that the Center for Private Seed Companies, which will be established at Gimje in 2015, plays an important role to make domestic seed companies improve their scale efficiency as well as pure technical efficiency by way of enlarging their size and co-using the high technology in the Center.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.26-32
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• 2023

In this study, we attempted to analyze the status of meal nutritional management at daycare centers and determine whether the need for improvement varies depending on their size. We divided into two groups based on the size of foodservice facilities. If meals for more than 50 people are provided at a time, they are classified as large-scale facilities (Large-scale group). If they are smaller, they are classified as small-scale facilities (Small-scale group). Dietitians visited each daycare center and checked 5 categories and 14 items. When comparing 5 categories, scores in the Small-scale group scored higher than those in the Large-scale group for 'Menu utilization' category. As a result of comparing the detailed 14 items, the scores of 'Indicate dietary information', 'Use menus suitable for those who are eligible for meals', and 'Posting menus by age in public places at foodservice facilities' were higher in the Small-scale group than in the Large-scale group. As such, there are differences in meal nutritional management according to the size of children's foodservice facilities therefore, it was found that customized education and management were needed according to the facilities' size.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 추계 학술대회 논문집
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• pp.301-306
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• 2005

나노 규모의 1차원 양자 구조물을 이용한 전자선 차폐 가능성에 관한 이론적 배경과 한계를 정리한다. 나노 구조물을 이용한 전자선 차폐는 차폐재의 경량화와 소형화에 크게 기여할 것으로 예상되나, 실용화를 위해서는 아직 연구되어야 할 분야가 많다. 임의의 1차원 포텐셜 장벽을 대상으로 양자투과계수 계산을 실행하여, 나노 구조물의 전자선 차폐와 관련된 문제점들을 살펴본다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.159-159
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• 2000

Initial growth mode of Nb on Cu(100) is studied by scanning tunneling microscopy (STM) and density functional theory. Nb/Cu is immiscible at room temperature, but isolated Nb atoms are expected to be incorporated up to the second layer by DFT. STM shows that Nb atoms mix with Cu atoms in the first layer at room temperature and diffuse into the second layer upon annealing. In the second layer, Nb/induced features are preferentially found at step edges and appear as bright dots surrounded by dark rings. Details of comparison between experiment and theory will be discussed.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.133-133
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• 2003

• Corrosion Science and Technology
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• 제11권3호
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• pp.82-88
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• 2012

The thickness and chemical composition of oxides on heat recovery steam generator tubes of combined cycle power plant were examined in order to evaluate the corrosion of the tubes. Tubes were removed from the plant after actual operations for 21,482, 42,552 and 56,123 hours respectively. Thickness and growth rate of the oxide scale on reheater inner tube (SA213-T22) were very high compared to those other tubes. The oxide scale was about $250{\mu}m$ thick and uniform. The components of the scale were iron oxides. The oxide scale was mixed oxides consisting of magnetite$(Fe_3O_4)$ and hematite$(Fe_2O_3)$. The oxide on inner tube was removed using many kinds of chemicals and it was found that chelating agents were dissolved faster than other chemicals.