• Journal of Korea Water Resources Association
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• v.51 no.7
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• pp.543-554
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• 2018

A methodology has been presented for evaluating the partial safety factors on the sliding failure mode of vertical caissons of composite breakwaters and for determining the cross sections of those by Level I reliability-based design method. Especially, a mathematical model has been suggested for the sake of a consistency of code format as well as convenience of application in practical design, for which the uncertainties associated with buoyancy and its own weight can be taken into account straightforwardly. Furthermore, design criteria equation has been derived by considering accurately the effect of uplift pressure, so that the cross sections of caissons can be assessed which must be safe against the sliding failure. It has been found that cross sections estimated from partial safety factors proposed in this paper are in very good agreement with the results of Level II AFDA and Level III MCS under the same target probability of failure. However, partial safety factors of the Technical Standards and Commentaries for Port and Harbour Facilities in Japan and Coastal Engineering Manual in USA tend to estimate much bigger or smaller cross sections in comparison to the present results. Finally, many reliability re-analyses have been performed in order to conform whether the stability level of cross section estimated by Level I reliability-based design method is satisfied with the target probability of failure of partial safety factors or not.

• The Journal of Korean Philosophical History
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• no.37
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• pp.97-134
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• 2013

Kim Ee-man was born and grew up in Jecheon (堤川). As a government officer and a Confucian scholar belonging to Namin School, Kim Ee-man was active in the early and middle of 18th century. Kim Ee-man composed good poems since he was a child. In addition to being a good poet, Kim Ee-man later became a model government officer, who had thorough awareness on serving citizens (爲民). When he was a governor in Yangsan (梁山) county, he built an embankment for farmers by out of his own salary. The academic world of Kim Ee-man faithfully succeeded the basis of Toegyehak (退溪學) and he took Sohak (小學) as important. The reason of Kim Ee-man having established a practical guideline in the form of inscription and proverbs was also directly related to the issue of moral practice. Kim Ee-man also received the influence of ancient classic study from his teacher Lee Seo-woo (李瑞雨) and took Yookgyeong (六經, Six Classics in China) important in practice. Kim Ee-man started the study on Joojahak (朱子學, the doctrines of Chu-tzu) in later years. He became more thorough in being a public figure while reinforcing effort on differentiating the principle of heaven (天理) and human desire (人欲).

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.87-98
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• 2023

In this study, we investigated the change in science core competency perception of high school students and the reason for change when science inquiry classes were conducted using eight 'skills' of the 2015 revised science curriculum. Fifteen first-year high school students in Jeollanam-do participated in the science inquiry class of this study, and the class was conducted for 20 hours (5 hours a day for four days). The inquiry activities used in the class consisted of four activity stages (research problems, research methods, research results, and conclusions) and each stage was constructed to include at least one 'skill (Problem Recognition, Model Development and Use, Inquiry Design and Performance, Data Collection, Analysis and Interpretation, Mathematical Thinking and Computer Application, Conclusion and Evaluation, Evidence-based Discussion and Demonstration, and Communication)'. As a result of the study, students' perception of the five science core competencies increased statistically significantly at the significance level of 0.01 through inquiry classes and more than 93% of students recognized that their science core competencies improved through the classes. However, since the class of this study was conducted for a small number of students, it is difficult to generalize the effect of the class, and so it is necessary to conduct a quantitative study for many students.

• Journal of Educational Research in Mathematics
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• v.21 no.4
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• pp.327-344
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• 2011

This study is the first step for us toward improving high school students' capability of statistical inferences, such as obtaining and interpreting the confidence interval on the population mean that is currently learned in high school. We suggest 5 underlying concepts of 'discretion of contingency and inevitability', 'discretion of induction and deduction', 'likelihood principle', 'variability of a statistic' and 'statistical model', those are necessary to appreciate statistical inferences as a reliable arguing tools in spite of its occasional erroneous conclusions. We assume those 5 concepts above are to be gradually developing in their school periods and Korean mathematics textbooks of grades 1-12 were analyzed. Followings were found. For the right choice of solving methodology of the given problem, no elementary textbook but a few high school textbooks describe its difference between the contingent circumstance and the inevitable one. Formal definitions of population and sample are not introduced until high school grades, so that the developments of critical thoughts on the reliability of inductive reasoning could not be observed. On the contrary of it, strong emphasis lies on the calculation stuff of the sample data without any inference on the population prospective based upon the sample. Instead of the representative properties of a random sample, more emphasis lies on how to get a random sample. As a result of it, the fact that 'the random variability of the value of a statistic which is calculated from the sample ought to be inherited from the randomness of the sample' could neither be noticed nor be explained as well. No comparative descriptions on the statistical inferences against the mathematical(deductive) reasoning were found. Few explanations on the likelihood principle and its probabilistic applications in accordance with students' cognitive developmental growth were found. It was hard to find the explanation of a random variability of statistics and on the existence of its sampling distribution. It is worthwhile to explain it because, nevertheless obtaining the sampling distribution of a particular statistic, like a sample mean, is a very difficult job, mere noticing its existence may cause a drastic change of understanding in a statistical inference.

• The Journal of Korean Association of Computer Education
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• v.5 no.2
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• pp.111-121
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• 2002

Our study illustrates how the use of web materials written with Mathview affects vocational high school students' learning in terms of formative evaluation. Our first attempt to develop high school math with Mathview has been guided according to current math texts due to highly structured format of math contents and low learning competencies of vocational high school students. The 6 female students who participated for about 12 hours in this study revealed their responses through interview data. descriptive surveys and field notes. Contrary to the original expectation. the results of data analysis showed that the students seem to prefer using conventional learning methods even though they were motivated by powerful graphical display of Mathview and algebraic manipulation capability. The overall responses of those.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.287-296
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• 2017

Robots are used in early childhood education as a new instructional media, and educational activities using robots have been increased. So the purpose of this study is to investigate the effect of educational activities using hands-on robots on logic-mathematical knowledge and creative problem-solving ability of young children. The total number of subjects was 43, and they were all five-year-old children. The experimental group and control group did activities with hands-on robots and general free activities, respectively. Results using ANCONA have shown that the activities with hands-on robots positively affected logic-mathematical knowledge and creative problem-solving ability of young children. These meaningful results have shown the possibility of early childhood educational use as the effectiveness of hands-on robots has come out.

• Journal of The Korean Association of Information Education
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• v.17 no.2
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• pp.177-189
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• 2013

According to a comparison study of international academic achievements, Korean students showed high academic achievements in science and mathematics, whereas their learning motivation appeared relatively low. Therefore, this work developed the robot-based STEM integrated education program reflecting an engineering class model. The title of the program is determined as 'animals' which are included in one section of the fourth grade science curriculum, are friendly to students, and are effective for robot application. Robot-based STEM program is consisted of three areas: robot education, subject-related course learning, and engineering education. The STEM program was reviewed by 14 teachers. The study result presented that regardless of knowledge of robot, most teachers gave positive response to program goal, composition of contents, application of robot.

• Journal of Advanced Navigation Technology
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• v.14 no.4
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• pp.562-570
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• 2010

The transmission phenomenon of neuron action potential due to exterior stimulation is somewhat identical to electrical reaction configuration. Therefore, I tried to analyze the transmission status of membrane excitation, by introducing electrical concept to this issue in this paper. First of all, I researched the complex electrical status of axon, and then simplified the electrical circuit into pure resistance circuit under the assumption that it was reasonable in practice. And I derived the transmission status of exciting action potential through the simplified circuits using electical theory and mathematical concept. I calculated overshoot potential of a certain portion and then confirmed that it excited neighbor portion and made it to be transmitted using the proposed data which was typical in point of biological and electrical view to verify this result.

• Journal of the Korean School Mathematics Society
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• v.15 no.3
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• pp.429-451
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• 2012

This paper examined eight novice elementary teachers' knowledge in terms of the types and sources of students' errors and teaching strategies on plane figures through a questionnaire and teachers' discussion. The teachers tended to predict students' diverse error types, but they attributed the sources of such errors mainly to their characteristics. The analysis of teachers' responses of teaching strategies revealed that they recognized the importance of the teacher's clear explanation and students' own problem-solving, while they were somewhat negative in presenting diverse examples and classifying, drawing, or constructing figures. Building on these results, this paper provides the implications for novice teachers' professional development programs.

• The Journal of Korean Association of Computer Education
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• v.15 no.5
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• pp.33-41
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• 2012

Elementary school students should have many opportunities to find their abilities and talents. However, informatics education in Korea does not target the entire elementary school students, opportunities for informatics education are given only to some students. Unlike possibilities to find mathematics gifted students and science gifted students, opportunities to find informatics gifted students are very limited. This study aims to solve current problems through a robot education program based on SEM(Schoolwide Enrichment Model). Using modified curriculum and school enrichment cluster, robot programming education is implemented at the pilot school. The result shows that robot education program based on SEM improved creative potentials of elementary school students.