• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.75-76
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• 2015

콘센트-플러그는 사용자부하에 전기를 공급하기 위하여 필수적으로 사용하는 전기부품이다. 활선상태인 콘센트-플러그를 임의로 차단할 경우, 교류환경에서는 반주기 마다 전류의 영점이 존재하므로 차단접점에서 발생하는 아크가 자연적으로 소호될 수 있으나 직류환경에서는 개방직전 전류가 영점을 포함하지 않고 일정하기 때문에 그에 따라 발생하는 아크는 교류에 비해 지속적이고 상대적으로 매우 큰 에너지를 방출한다. 교류에서 사용되는 플러그와 콘센트를 그대로 직류에서 사용 할 경우, 접속이 끊어 질 때 매우 큰 아크전류가 발생하여 플러그와 콘센트의 전극이 녹아서 붙는 융착 사고가 빈번히 발생한다. 본 논문은 콘센트-플러그의 융착 사고를 예방하기 위해 전극의 초기-후기접점 기법을 제안한다. 이를 구현하기 위한 기초적인 연구로서 초기-후기접점 저항을 2단계로 구분하여 접속 및 차단 시 중간단계의 접촉저항을 통하여 부하전류가 단계적으로 바뀔 수 있도록 함으로써 최종 차단 아크전류를 감소시키는 방법을 제안하고 실험을 통하여 성능을 분석하고 설계방법을 제시한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.01a
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• pp.341-344
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• 2021

현재 우리나라는 소프트웨어(SW)에 대한 관심 증가에도 불구하고 초등 소프트웨어 교육을 위한 표준 교육 계획이 마련되지 않아 체계적인 교육을 통한 컴퓨팅 사고력 배양이 어려운 상황이다. 따라서 본 논문에서는 언플러그드 활동을 통해 컴퓨팅 사고력을 증진시킨 후 이를 바탕으로 코딩 문제해결능력을 향상시킬 수 있는 교육 콘텐츠의 필요성에 대해 인식하였고, 언플러그드와 블록 코딩을 연계한 초등 소프트웨어 교육 계획을 제안한다. 교육 계획은 소프트웨어에 대한 접근, 언플러그드 교육을 통한 컴퓨팅 사고력 향상, 코딩 교육을 통한 문제 해결 능력 향상 과정 등 총 3단계로 구성되었다. 개발된 콘텐츠의 매 주제는 언플러그드 교육과 코딩 교육이 서로 연계되도록 구성하여, 코딩 개념 학습 및 이와 연관된 컴퓨팅 사고력 향상 후, 학습된 내용을 코딩 과정에서 실체화 하도록 하여 응용력이 배양될 수 있도록 하였다.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.329-333
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• 2001

The study was performed to investigate the effect of a plug culture method in the early stage of a potato breeding program. The 105, 200 and 288-cell plug trays were used for raising potato seedlings. The % germination in plug trays ranged between 94 and 96%. Percent tuberization measured at 50 and 60, and 70 days after sowing was the greatest in 105-cell and 200-cell trays, respectively. However, tuberization was most delayed in 288-cell trays. Thus, it is considered that 105-cell tray is the most effective for the selection of early maturing plants. Plant maturity was determined by the morphological characteristics at the seedling stage of stolons cultured in plug trays. Most of seedlings with shorter stolons at seedling stage (1st generation) were the early-maturing, while most of seedlings with longer stolons were the late-maturing at the clonal stage (2nd generation). These results mean that the plant maturity in the early potato breeding program can be effectively grouped by observing the morphological characteristics of stolons after plug culture.

• Journal of The Korean Association of Information Education
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• v.15 no.1
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• pp.31-38
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• 2011

This study proposed a new education program for the information science gifted talent using unplugged computing and EPL that are new teaching approach of computer science. We analyzed unplugged computing contents and developed the advanced educational program for the information science gifted talent. We also made up a curriculum and teaching strategy and applied the elementary information science gifted talents the developed program with unplugged computing. In order to verify an effectiveness of new program, we tested t-test and found the positive results between before and after the program as well as an experimental group and the comparison group. In interview and observation about the gifted talents, we also saw that the students evaluated an unplugged computing lesson to the positive responses. We expect the proposed unplugged computing program will give many help for teaching the information science gifted talent.

• Tunnel and Underground Space
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• v.21 no.6
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• pp.526-535
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• 2011

A new failure criterion for concrete, which takes into account the effect of the intermediate principal stress, is proposed. The new criterion, which takes the advantages from both the Mohr-Coulomb and the Willam-Warnke criteria, is linear in the meridian section, while its octahedral section is always smooth and convex. Fitting the triaxial compression data with the proposed criterion shows the high performance of the new criterion. A new formula for the factor of safety of concrete is defined based on the new failure criterion and it is employed in the stability analysis of the concrete plugs installed in the pilot plant. The new formula for the factor of safety measures the degree of closeness of a stress state to the failure surface in the octahedral plane. Finally, 3-D finite element analyses of pilot plant were carried out to obtain the stress distributions in the plugs. Then, the stress distributions are converted to those of factor of safety by use of the proposed formula. Based on the distribution of factor of safety in the concrete plugs, the stability of the tapered and wedge-shaped plugs is evaluated.

• Journal of Software Engineering Society
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• v.24 no.2
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• pp.67-75
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• 2011

In order to improve working speed, add more functions and provide better user interface of ASADAL, the AWT based Java application to support FORM Software Product Line Development Methodology; we had to reengineer this application to be Eclipse based plug-in application. In order to improve working speed, add more functions and provide better user interface of ASADAL, the AWT based Java application to support FORM Software Product Line Development Methodology; we had to reengineer this application to be Eclipse based plug-in application. And then, this paper introduces the plug-in developed by applying guidelines presented in the reengineering cases of ASADAL's feature model editor and behavior model editor.

• Journal of Creative Information Culture
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• v.6 no.2
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• pp.77-88
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• 2020

The purpose of this study is to statistically analyze the correlation between CS Unplugged education and the computational thinking of gifted and talented students. In this study, qualitative research was conducted for 17 students in 5th grade gifted class at an elementary school in the city of Yongin. Students participated in 10 hours of CS unplugged classes. Student questionnaire, class journals, student activity sheets, and student interview records were collected and qualitatively analyzed. In order to supplement the qualitative data, computational thinking ability tests were also administered. The results of the study are as follows. First, CS unplugged education plays an effective role in improving CT of gifted and talented students. Second, it was not every sub-area of CT that CS unplugged education brought statistically significant improvements in. Third, CS unplugged education is suitable to be presented as the first step of the SW curriculum for gifted and talented students.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.381-390
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• 2018

This study was conducted to examine the growth characteristics of seedlings of several major fruit vegetables and compare them between plants grown with the conventional plug seedling system (Plug) and those grown with the cylindrical paper pot system (CPP). There were no significant differences in shoot growth characteristics, such as plant height, leaf area, dry weight, and fresh weight, between tomato, cucumber, and watermelon plants grown with the CPP and Plug systems. The total root lengths of tomato and cucumber plants grown with Plug were longer than those grown with CPP at the beginning of seedling growth, and the total root lengths of watermelon grown with Plug were longer than those grown with CPP throughout the whole seedling period. The length of root that separated five steps according to the diameter of the root of tomato did not differ between CPP and Plug, but those of cucumber and watermelon were 20-251% longer with Plug than with CPP for all kinds of roots. The fresh weight of Plug-grown tomato roots was about 30% heavier than that of CPP-grown tomato during the seedling period, but the difference decreased as growth progressed. Finally, there was no difference between plants before and after transplanting. The fresh weights of the Plug-grown plants were about 20-30% heavier than those of CPP-grown ones in terms of the whole seedling. After transplanting to the Wagner pot, the shoot growth of Plug-grown watermelon plants in terms of dry weight was low until 7 days had passed. However, this tendency was reversed from 8 days after transplantation onward. In conclusion, there were no significance differences in the growth of shoots between plants grown with the CPP and Plug systems. However, root development was better with Plug than with CPP.

• Journal of The Korean Association of Information Education
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• v.20 no.1
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• pp.93-100
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• 2016

Computer Science Unplugged is a collection of free learning activities that teach Computer Science through engaging games and puzzles that use cards, string, crayons and lots of running around. In spite of the success of unplugged activities, the unplugged resources for experiencing the concepts of data structures is lacked. In this study, we design, implement and survey the 3 hour lessons of the core concepts of graph theory and the shortest path algorithm for the primary students using computer science unplugged activities. Our survey results showed that our lesson plan is adequate for primary school students and will have a positive effects for primary school students.

• Journal of The Korean Association of Information Education
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• v.22 no.4
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• pp.409-417
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• 2018

There are unplugged computer science activities for elementary school students to learn the concept of the Internet. However, these activities are not enough to teach the concept of the Web because they focus on teaching how the Internet works. Since the Web is the core technology of the Third Industrial Revolution, it needs to be understood as a basic common sense. In this paper, we developed an unplugged activity to understand the PageRank algorithm which is closely related to the web. The experimental results show that our unplugged activities behave similarly to the PageRank algorithm.