• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.648-648
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• 2015

이 연구는 수자원 환경을 전반적으로 객관화, 계량화하는 새로운 방법이 성공적임을 소개한다. 기존의 계량법이 일강수량, 월 강수량, 년 강수량 등등, 단순한 수학적 합계에 치중한 결과 가중 중요한 강수의 시간 분포를 간과하였다. 이 단점을 해결하여, 1) 구체적으로 매 시간, 매일 남아 있다고 추정되는 물의 양 만을 합산하는 방법을 택했다. 시간적 감소함수를 이용하여, 강수 후 유출과 증발 등으로 사라지는 물의 양을 고려한 것이다. 2) 합산기간을 객관화하였다. 기본 합산 기간을 365일로 하고, 물 부족 또는 물 과잉이 지속될 경우는 지속되는 기간만큼, 합산기간을 늘이는 방법을 택했다. 따라서 다른 지수들이 임의로 3개월 또는 12개월 등등으로 기간을 결정하는 단점을 해결했다. 이렇게 계산되는 4차원 강수지수(4-Dimensional Rain Index, 4RI)는 1) 일별유효강수지수 (AWRI), 2) 일별가뭄지수(EDI), 3) 일별 홍수지수(FI), 4) 시간별 장기 물지수(LWI), 5) 시간별 단기 물지수(SWI) 등 5개가 기본지수이다. AWRI는 매일 남아 있는 물의 양이다. 이로 인해, 전 지구의 수자원과 재해위험의 시공간적 분포의 정량화 분석이 정밀해졌다. 지구상에서 물 집중이 가장 강한 곳은 캄보디아 내의 한 지점이며 시기는 7월 말이고, 가장 약한 곳은 사하라 사막의 한 지역임이 확인되었다. 또 한국에서 발생하는 갈수기와 풍수기가 정의되었고, 이들의 각 지역별 특성과 차이가 정량적으로 드러났다. 시간적 분포 또한 명확하게 드러나, 각종 저수지의 물 관리나 농?임산물의 생산관리에 획기적 전환점이 마련되었다. 각 국가별로, 각 지역별로 이런 분석은 향후도 무수히 시도되어야 할 것이다. EDI는 매일의 AWRI를 그 날짜의 평균치와 비교한 값이다. 장기가뭄 및 단기가뭄의 강도를 모두 가장 정밀하게 표현한다. FI는 일별로 홍수, 산사태, 침수, 토사 (이하 홍수 등이라 칭함)의 위험을, LWI는 장기 누적된 강수량에 의한 돌발적 홍수 등의 위험을, SWI는 단기 누적된 강수량에 의한 돌발적 홍수 등의 위험을 잘 반영한다. 이들은 모두 시간적으로 산발적인 호우에 의한 홍수 등의 위험을 한 개의 지수로 표현해 주는 장점이 있다. 강수 후 홍수가 발생하기 까지는 시간차이가 있기 때문에, 특히 호우 경보에는 SWI가, 홍수 경보에는 LWI가 아주 효과적이다. 결론적으로 5개의 4차원 강수지수는 물환경의 시공간적 분포진단과 예측, 그리고 조기경보에 혁명적 진화를 초래함이 확인되었다. 따라서 추후 모든 강수기후와 연관된 연구는 연강수량 등의 단순 합산보다, 4차원 강수지수를 먼저 사용하는 것이 바람직 할 것임이 제안되었다.

• Journal of the Korean School Mathematics Society
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• v.9 no.4
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• pp.575-595
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• 2006

In this paper, we investigated the effects of mathematics classes using play-action programs in the course of mathematics education of future elementary school teachers. This study was conducted with 43 junior university students who selected 'Play Mathematics' in 2006. All the participants in this course was divided 11 groups. Play-action mathematics programs was consisted of 12 themes. For example, there was tangram, somacube, hexamino, tessellation, geoboard etc. In the beginning of lessons, we investigated theses themes itself through plays, puzzles, games, and computer programs. And next time, we investigated the relationships between these themes and elementary mathematic textbooks(i.e. mathematical contents). In 14th and 15th lessons, all the groups took a project presentation lessons that included all things about play mathematics in all group categories. And they developed two themes of play mathematics in accordance with grades, contents, levels as course tasks. Through this study, three educational effects induced. First, future elementary school teachers have a deep understanding about play-action mathematics. They are interested in these play themes, and take part in these play mathematics programs of their own accord. And they realize that these play themes are related to elementary mathematics. Second, future elementary school teachers' attitude and mind about mathematical are improved after this course. Third, future elementary school teachers comprehend various instruction methods relating to play mathematics. Therefore, we suggest that future elementary school teachers need to have many opportunity to experience and develop a mathematics classes using play mathematics.

• Journal of The Korean Association of Information Education
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• v.15 no.3
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• pp.375-385
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• 2011

Computer education is moving its focus from skill oriented education to improving students' creativity and problem solving ability. Thus, the importance of programming education is being strengthened. However, programming education was biased to grammar oriented language that has been limits of students' interest. Robot programming is problem solving itself, and by allowing students to directly see the robot which is the output of programming, can help interest and motivate to the students. In fact, it is still observed that the students are facing difficulties due to various kinds of errors during the programming education. Therefore, this study categorizes and analyzes the errors students are facing during robot programming, and based on that, a support tool to help treat errors developed. The developed supporting system for error solving reduces the frequency of errors and provides the set of coding instruction, NXC language and error message in Korean, examples and detailed information for each stage of education, function removing major coding errors, and code sorting and indication of row number. This study also confirmed that the supporting tool is helpful in reducing and solving errors after input.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.29.2-29.2
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• 2009

구리는 낮은 비저항, 높은 열전도도, 우수한 electromigration(EM)저항특성 등을 바탕으로 차세대 nano-scale집적회로의 interconnect application에 적합한 금속재료로서 각광받고 있다. copper interconnect는 damascene process 를주로 이용하는데 CVD를 이용하면 step coverage가우수한 seed layer얻을 수 있어 고집적 소자의 구현이 가능하다. 최근에 비 균등화 반응(disproportionationreaction)을 이용하여 고 순도 구리박막을 제조하기위해 $\beta$-diketonate Cu(I) Lewis-base의 전구체를 많이 이용하는데 그중에서 hexafluoroacetylacetonate(hfac)Cu(I)vinyltrimethylsilane (VTMS)가 널리 이용되고 있다. 그러나 (hfac)Cu(I)(VTMS) 또는 유사계열의 전구체들은 열적안정성및 보관안정성이 부족하여 실제 양산공정에 적합하지 못한 단점이 있었다. 본 연구에 이용된 2가 전구체Cu(dmamb)2는 높은 증기압($70^{\circ}C$, 0.9torr)을 가지며 종래에 주로 이용하던 1가 전구체 (hfac)Cu(VTMS)에 비해 높은 활성화 에너지(~113 kJ/mol)를가짐으로서 열적안정성 및 보관안정성이 우수하다. 다른 한편으로 2가전구체는 안정성이 우수한 만큼 낮은 증기압을 극복하기 위해 리간드에 플루오르를 주로 치환하여 증기압을 높이는데 플루오르는 성장하는 박막의 접착력을약하게 하는 단점을 가진다. 하지만 본 연구에 사용된 Cu(dmamb)2는 리간드에 플루오르를 포함하지 않으며, 따라서 고품질의 박막을 용이한성장환경에서 제조할 수 있는 장점들을 제공한다. 비활성가스 분위기에서 2가전구체는 열에너지에 의해 리간드의 자가환원에따라 금속-리간드 분해가 발생한다. 하지만 수소분위기에서는수소가 환원제로 작용하여 리간드의 분해를 용이하게 하는 특징을 가지며 따라서 비활성분위기일 때 비해 낮은 성장온도를 가진다. 또한 수소는 잔류하는 리간드 및 불순물과 결합하여 휘발성화학종들을 생성하여 고순도의 구리박막제조를 가능하게한다.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.2 s.152
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• pp.148-153
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• 2007

Two typical impact loadings, shock wave and gas bubble pulse, due to UNDEX(UNDerwater EXplosion), should be considered together for the closest response analysis of structure subjected to UNDEX to a reality. Since these two impact loadings have different response time bands, however, their response characteristics of structure are different from each other. It is impossible to consider these effectively under the current computational environment and the mathematical model has not yet been developed. Whereas Hicks model approximates the fluid-structure interaction due to gas bubble pulse as virtual mass effect, treating the flow by the response of gas bubble after shock wave as incompressible ideal fluid contrary to the compressible flow due to shock wave, Geers-Hunter model could make the closest response analysis of structure under UNDEX to a real one as a mathematical model considering the fluid-structure interaction due to shock wave and gas bubble pulse together using acoustic wave theory and DAA(Doubly Asymptotic Approximation). In this study, the application and effectiveness of integrated dynamic response analysis of submerged structure was examined with the analysis of the shock wave and gas bubble pulse together.

• Journal of the Korean School Mathematics Society
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• v.13 no.3
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• pp.381-395
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• 2010

The purpose of this paper is to examine the competence and the methods of problem solving in four operations word problems based on the informal knowledges by five-year-old children. The numbers which are contained in problems consist of the numbers bigger than 5 and smaller than 10. The subjects were 21 five-year-old children who didn't learn four operations. The interview with observation was used in this research. Researcher gave the various materials to children and permitted to use them for problem solving. And researcher read the word problems to children and children solved the problems. The results are as follows: five-year-old children have the competence of problem solving in four operations word problems. They used mental computation or counting all materials strategy in addition problem. The methods of problem solving were similar to that of addition in subtraction, multiplication and division, but the rate of success was different. Children performed poor1y in division word problems. According to this research, we know that kindergarten educators should be interested in children's informal knowledges of four operations including shapes, patterns, statistics and probability. For this, it is needed to developed the curriculum and programs for informal mathematical experiences.

• Journal of Educational Research in Mathematics
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• v.13 no.2
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• pp.159-178
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• 2003

This study analyzes on the reasoning in the process of justification and mathematical problem solving in our primary mathematics textbooks. In our analyses, we found that the inductive reasoning based on the paradima-tic example whose justification is founnded en a local deductive reasoning is the most important characteristics in our textbooks. We also found that some propositions on the properties of various quadrangles impose a deductive reasoning on primary students, which is very difficult to them. The inductive reasoning based on enumeration is used in a few cases, and analogies based on the similarity between the mathematical structures and the concrete materials are frequntly found. The exposition based en a paradigmatic example, which is the most important characteristics, have a problematic aspect that the level of reasoning is relatively low In Miyazaki's or Semadeni's respects. And some propositions on quadrangles is very difficult in Piagetian respects. As a result of our study, we propose that the level of reasoning in primary mathematics is leveled up by degrees, and the increasing levels are following: empirical justification on a paradigmatic example, construction of conjecture based on the example, examination on the various examples of the conjecture's validity, construction of schema on the generality, basic experiences for the relation of implication.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.2
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• pp.355-376
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• 2010

This research was about analyzing students' major error types in the field of elementary 1st grade mathematics numbers and operations, and formulating and applying effective teaching methods to find out their effects. Among the errors the students were making, it was found that in the field of numbers there was more than 50% chance of making calculation mistakes in 50 rounds of rational counting. Also, in the field of operations, it was discovered that most of students' mistakes had to do with subtraction. The results from the classification of the 4 types of error showed that most errors were made from having inaccurate concept of knowledge and definition. Thus, it can be concluded that when elementary 1st grade teachers teach students mathematics, it is most important that they put best effort into firmly establishing the students fundamental concept, definition, facts, and functions. For that matter, students were interviewed one by one, and by implementing learning method using some concrete materials as tools, students were able to fix their own errors. More importantly, students were able to gain interest and become more willing to participate by joining in this program, which led to more effective guidance.

• The Journal of the Korea Contents Association
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• v.8 no.6
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• pp.121-129
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• 2008

With the help of information technology The problem of building a concrete form with a shapeless media is the starting point of presenting information by means of sound. Audio-Visual System using sound as a medium is a method that presents an auditory material visually and has a role of linking different sensory organs. In a sense, Audio-Visual System transfers a non-concrete sensation to a concrete one. Audio-Visual System presentation by late methods using active and non-active images produced by computerized irregular procedures can be limited because of the limited ways of visual output. On the other side, visualization using active images can induce more diverse expressions using sound as a medium. This study suggests a new way of expression in animations using visualization of various auditory materials and sounds built by Audio-Visual System with active images.

• Korean Journal of Childcare and Education
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• v.7 no.1
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• pp.93-120
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• 2011

This study was aimed at inquiring into the role characteristics of a early childhood teacher, who can put an act of tending & examining into practice, and organizing a role by analyzing the concrete reality based on the relationship with a early childhood teacher's role in Korea and Japan. As a result, this study could take a look at the characteristics, such as relation with conversation, relation through sensation and body, relation with familiarity, and relation by living through the cases in Korea. As for the cases in Japan, there appear the characteristics, such as relation through natural things, relation as an equal participant, relation with bodily movement, and relation with daily life. Based on the result of the analysis, this study organized a early childhood teacher's role as relationship through object-oriented language, relationship based on sensation, relationship based on fellowship, and ecological relationship.