• Journal of the Korean School Mathematics Society
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• v.17 no.4
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• pp.805-816
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• 2014

In this paper, we survey the development of material implication and we present an analysis of the students' understanding of formal implication. Most of high school students consider material implication $p{\rightarrow}q$ as ${\sim}p{\vee}q$ when they represent the pattern of a collected cards as material implication $p{\rightarrow}q$. But when they collect cards in which material implication $p{\rightarrow}q$ is true, Most of high school students consider $p{\rightarrow}q$ as $p{\wedge}q$.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.547-547
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• 2016

최근 지구온난화로 인한 기후변화는 우리 삶에 다양하게 영향을 미치고 있다. 강수 또는 기온의 비정상성으로 대표되는 기후변화에 따라 수문순환의 변화 역시 자명하게 받아들여지고 있다. 기후변화에 따른 위험요소를 전망하기 위한 최우선 사항은 수문상황을 명확하게 진단하는 것이고 그 다음은 현재기후를 대비 미래의 변화를 전망하는 것이다. 그러나 우리나라는 수문관측의 역사가 짧고 관측 자료의 불확실성으로 인하여 수문상황의 진단을 위해 수문모형의 모의에 의존하는 경우가 많다. 일반적으로 수문모형은 입력 자료와 지형자료를 구축하고 주요 매개변수를 선택하여, 매개변수를 변화시켜가며 관측에 가장 가까운 결과를 가져오는 상태를 구성한다. 이와 같은 과정은 수문모형의 매개변수 보정이라 불리우며, 사용자의 직관에 따른 시행착오법에 따른 수동보정 방법이 사용될 수도 있고 특정 목적함수를 채택하여 수학적 알고리즘에 의해 매개변수를 보정하는 자동보정 방법이 사용될 수도 있다. 그러나 미래 수문변화 전망은 특정 유역을 대상으로 장기간의 수문자료를 모의하는 것이므로 수동보정보다는 자동보정이 보다 신뢰성 있는 결과를 도출하는 것으로 알려져 있다. 따라서 본 연구에서는 청미천 유역의 기후변화로 인한 미래 수문상황의 변화를 모의함에 있어 강우 유출모형 중 하나인 SWAT 모형을 이용하였으며, 신뢰도 있는 매개변수의 추정을 위하여 SWAT-CUP을 이용하여 매개변수를 객관적으로 최적화하였다.

• The Mathematical Education
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• v.59 no.2
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• pp.131-146
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• 2020

Regarding the formula for measuring the area of a circle, the Archimedes' constant is generally written in front of the square of radius length, but there were a few cases where the Archimedes' constant was written after that in Germany and France. In this study, two things are studied: First, how many students are writing the Archimedes' constant after that? Second, what do the students think about the written order of characters in the formula for measuring the area of a circle? In the online survey of 201 people aged 14 to 21 in Korea, there was a perception of more than 86% that both are possible or only after that are possible. In this study, it is suggested that there is a difference between the general written order of characters and the natural perception of students formed through school education. In addition, students aged 14 to 16 thought more that the Archimedes' constant should be written after that, and after that age, there was a greater perception that both are possible without confusion of meaning. It can be seen that the change in students' perception has emerged through school education on natural mathematical written order of characters after middle school courses. From this point of view, the most common perception can be that if there is no confusion in meaning, then both expressions are possible.

• Journal of Elementary Mathematics Education in Korea
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• v.15 no.1
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• pp.199-219
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• 2011

In this thesis, we designed a experimental learning-teaching plan of 'decimal fraction concept' at the 4-th grade level. We rest our plan on two basic premises. One is the fact that a essential concept of decimal fraction is 'polynomial of which indeterminate is 10', and another is the fact that the origin of decimal fraction is successive measurement activities which improving accuracy through decimal partition of measuring unit. The main features of our experimental learning-teaching plan is as follows. Firstly, students can experience a operation which generate decimal unit system through decimal partitioning of measuring unit. Secondly, the decimal fraction expansion will be initially introduced and the complete representation of decimal fraction according to positional notation will follow. Thirdly, such various interpretations of decimal fraction as 3.751m, 3m+7dm+5cm+1mm, $(3+\frac{7}{10}+\frac{5}{100}+\frac{1}{1000})m$ and $\frac{3751}{1000}m$ will be handled. Fourthly, decimal fraction will not be introduced with 'unit decimal fraction' such as 0.1, 0.01, 0.001, ${\cdots}$ but with 'natural number+decimal fraction' such as 2.345. Fifthly, we arranged a numeration activity ruled by random unit system previous to formal representation ruled by decimal positional notation. A experimental learning-teaching plan which presented in this thesis must be examined through teaching experiment. It is necessary to successive research for this task.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.435-444
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• 2021

This paper discusses the geometrical interpretation of the Taegeuk Shapes of Kameun Temple through the geometric analysis of mathematics. Based on the literature, This paper attempted to clarify that the origin of Gameunsa's founding of the spirit of patriotism may coincide with historical records through historical literature and geometric meaning. First, the background of the founding of Kameun temple, geographical location located near the East Sea, especially the history of the ancient Chinese mathematics at the time, And that mathematical knowledge influenced all fields such as agriculture, architecture, and art. Secondly, it is related to the historical record as the space of about 60 centimeters, which is uniquely underground, was identified as the structure of the excavated space. It is thought that there is a strong correlation with the origin that the King Munmu changed into a dragon, and set up the temple to be able to stay. Based on these, the clues of the interpretation of the taegeuk and the triangular pattern were searched in the samcheon yanggi(參天兩地) of the Oriental and circumference of the Western. The taegeuk and triangular patterns represent the symbols of yin-yang harmony, which correspond to the origin of its creation. the Korean people regarded the mysterious dragon as a symbol of yinyang harmony. In conclusion the Shapes of Kameun temple's stone is consistent with the contents mentioned in the historical record.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.571-587
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• 1998

This paper reviews and analyzes the conceptions of science achievement in the United States and Korean reform documents, including those on science content standards(NSES, Porject 2061, and Korean 7th science curriculum), performance standards(New Standards, and Survey of Ecucational Achievement in Korean Elementary and Secondary Schools), and large-scale assessment framworks(1996 NAEP, TIMSS, The National Assessment of Science Inqury Abilities, The National Assessment of Science Knowledge, and The National Assessment of Affective Characteristics related to Science). The analysis of these documents indicates that there is an overall agreement on the conceptions of science achievement. The documents consistently emphasize high achievement in terms of knowledge and abilities in scientific, technological, social, and environmental perspectives. In addition, these documents define science achievement at different developmental levels and at certain depths of knowledge and abilities for all students. Despite the overall agreement, there are also noticeable variations among the documents because of different contexts and purposes. There is a difference in the balance of representations or emphases among content and process standards in the documents. The conceptions of science achievement in the Korean documents are not as comprehensive or inclusive as those in the United States documents. There is no representation of the mathematical world, the nature of science, historical perspectives, unifying concepts, or scientific communication. From these results, two conclusions are drawn. First, more coherent conceptions of science achievement are needed for common understanding among educators and the public. Second, efforts are needed for developing more comprehensive and inclusive conceptions of science achievement in Korea.

• Journal of the Korean School Mathematics Society
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• v.21 no.4
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• pp.303-326
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• 2018

Fraction has difficulties in learning because of the diversity of meanings, the ways of presenting contents and teaching methods in elementary school mathematics. Therefore, the various strategies of teaching of fraction concept is proposed as an alternative. The problem of equal sharing problem is that children can experience the concept of fractions naturally in the context of everyday distribution. Even before learning formal fractions, children can solve them in various ways based on their own experiences. The purpose of this study is to investigate the degree of problem solving and problem solving strategies for children in 2nd, 4th, and 6th grades in elementary school. As a result of the research, the percentage of correct answers increased as the grade increased, but the grade levels showed a difference depending on the numbers given to the problems. Also, there were differences in the problem solving strategies according to the grade levels. Also, according to the numbers presented in the problem, the percentage of correct answers was high in items that were easy to divide, and the percentage of correct answers was low in items that were difficult to divide. When children solved the problems, they were affected by the strategies they could use immediately according to the number presented in the problem, and their learning experiences were also affected.

• Journal of the Korean earth science society
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• v.43 no.2
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• pp.324-347
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• 2022

Geological information on the Korean Peninsula plays a significant role in science education because it provides a basic knowledge foundation for public use and creates an opportunity to learn about the nature of geology as a historical science. In particular, the Mesozoic Era, when the Korean Peninsula experienced a high degree of tectonic activity, is a pivotal period for understanding the geological history of the Korean Peninsula. This study aimed to analyze whether content regarding the geology of the Mesozoic Era are reliably and consistently presented in the 'Geology of the Korean Peninsula' section of Earth Science II textbooks based on the 2015 revised curriculum. Four textbooks for Earth Science II were analyzed, focusing on the sedimentary strata, tectonic movement, and granites of the Mesozoic Era. The analysis items were terms, periods, and rock distribution areas. The consistency within and among textbooks and of textbooks and scientific knowledge was analyzed for each analysis item. Various inconsistencies were found regarding the geological terms, periods, and rock distribution areas of the Mesozoic Era, and suggestions for its improvement were discussed based on these inconsistencies. It is essential to develop educational materials that are consistent with the latest scientific knowledge through collaboration between the scientific and educational communities.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.95-104
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• 2010

The tap water supply in Korea mainly depends on the surface water. However, the advanced water purification process becomes a necessity due to the deterioration of surface water quality and the risk of accidental spill. High cost of water treatment and public concerns make the decision makers turn to riverbank filtration as an alternative to the surface water. Riverbank filtration has been employed for water supply in many developed countries for more than 150 years. In Korea, riverbank filtration has drawn attention since 1990s as a supply source having potential to stably meet the ever-increasing water demand. Some cities located in the Nakdong River Basin are currently supplying water through riverbank filtration. This work studies the site suitability analysis for riverbank filtration using game theory. Theory of games, which is a branch of applied mathematics used in social sciences (most notably economics), biology, engineering and computer science, was applied to candidate locations for the selection of riverbank filtration site. We proposed a policy game model as a new method adopting a probabilistic approach. The model developed turned out to be an effective tool for site selection.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.105-111
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• 2020

We defined Jeju Wind Castle and analyzed the relationship between Hallasan-Oreum-Batdam, the main subject, for the first time. In Jeju, 1.5m high Batdam(Black Silk Road), 368 Oreums, Hallasan Mountain 1950m are all unique scenery. The verification of this paper demonstrates that Samdasoo's groundwater extraction sea level is equal to the height of Hallasan and that this problem is mathematically complete in neutral plane theory. Donnaeko(700meters above sea level)-Baeknokdamdongneung-Jindallebat-Seongpanak-Gyorae(453 meters)-Witsaeoreum(1700meters) is a rain belt that hits the low-air pressure air-conditioned North Pacific humidity rising from the southeast and the high-pressure cold air of Hallasan Peak. It rains a lot because - and + are neutral plane, which adds to zero. Hallasan is called Jinsan in Jeju history. The answer is Wind Castle. The number of Oreum in Jeju is 369 including Hallasan, and Batdam, which is about 1.5m high, does not collapse even with a typhoon blowing over 50m/s. Because the wind castle's core is 1.5 meters of Batdam and it is a triangular number.