• Journal for History of Mathematics
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• v.21 no.1
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• pp.139-156
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• 2008

We investigate the inducing method of irrational numbers in junior high school, under algebraic as well as geometric point of view. Also we study the treatment of irrational numbers in the 7th national curriculum. In fact, we discover that i) incommensurability as essential factor of concept of irrational numbers is not treated, and ii) the concept of irrational numbers is not smoothly interconnected to that of rational numbers. In order to understand relationally the incommensurability, we suggest the method for inducing irrational numbers using construction in junior high school.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.1
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• pp.65-72
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• 2003

The objective of this study is to estimate the frequency characteristics of group walking loads based on the information of measured responses. At first, dynamic properties such as natural frequencies and modes are obtained from input/output relation for building structures by heel drop test. Second, a method to estimate group walking loads by the transfer functions from measured responses to group walking loads is proposed. The method turned out to estimate the group walking loads accurately. Higher modes could be important in estimating the amplitude of group walking loads with the information of single walking load.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.41-49
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• 2009

This research conducted a survey on the feeding crane's size, formation and distribution distance subsequent to road pattern and feeding flock's size during the wintering season eight times at the Cheolwon basin in Korea from December 2005 until February 2006. The survey results are as follows: First, the feeding flocks of the Red-crowned and White-naped Crane were found to mainly consist of two to four individuals. Mono-specific feeding flocks were more identified than hetero-specific feeding flocks in both Red-crowned and White-naped Cranes. There existed a significant difference in the ratio by size between the feeding Red-crowned and White-naped Cranes. The crane's average distribution distance from the paved road was much farther than from the unpaved road, paved farm road and unpaved farm road. In case of the white-naped crane, there was a difference in its distance length from between the road and farm road and there existed a significant difference only in the paved road in the distance length by road pattern between these two bird species[Red-crowned and White-naped Crane]. Such a result indicates that crane species don't prefer the road with frequent vehicular traffic to the road with low vehicular traffic. 5 or more individuals of feeding flocks of the Red-crowned Crane were located at a farther distance length from the paved road comparing to less than 5 individuals of the whole feeding flocks and less than 5 individual feeding flocks. 5 or more individuals of feeding flocks of the White-naped Crane were located at a farther distance length from the paved road, paved farm road and unpaved farm road than less than 5 individuals of feeding flocks of the White-naped Crane; however, there existed no difference in distance length subsequent to their group size. Conclusively, it was found out that the flocks with a larger size were more greatly affected by interrupting factors. Considering such results, there seems to be a more relation to the fact that larger size feeding flocks of crane species have a higher efficiency in the lookout for their surroundings.

• Journal of the Korean School Mathematics Society
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• v.23 no.3
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• pp.277-297
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• 2020

The purpose of this study is to understand how the shift of the Pythagorean theorem influenced the representation of irrational numbers in the 3rd grade textbook of 2015 revised mathematics curriculum by textbook analysis. Specifically, the changes in the representation of irrational numbers were examined in two aspects based on the nature of irrational numbers and the teaching and learning methods of the 2015 revised mathematics curriculum. First, we analyzed the learning opportunities related to the existence of irrational numbers that were potentially provided by treating irrational numbers as geometric representations in textbooks, and confirmed that Pythagorean theorem was used. Next, we analyzed opportunities to recognize the necessity of irrational numbers provided by numerical representations of irrational numbers. This study has significance in that it confirmed the possibility and limitation of learning opportunities related to the existence and necessity of irrational numbers that were potentially provided by changes in irrational number representations in the 2015 revised textbooks.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.1010-1013
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• 2010

무리짓기 시뮬레이션은 무리를 짓는 NPC의 인공 지능을 구현하는 것으로 게이머들에게 실세계와 같은 몰입에 도움을 준다. 이를 위하여 본 논문은 분석된 실세계에서의 물고기 무리짓기의 행동 패턴을 오우거 엔진을 이용하여 구현[1]하고, 이를 실세계의 물고기 떼의 행동 패턴과 비교하였다.

• Journal of the Korean School Mathematics Society
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• v.16 no.3
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• pp.499-518
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• 2013

The purpose of this study is to examine the preservice secondary mathematics teachers understanding and dimensions of knowledge about definition of irrational numbers and irrational numbers and operations. I adopted a framework consisting of formal dimensions, intuitive numbers, algorithmic dimentions suggested by Tirosh et al.(1998) by adding instrumental dimension for his study. I surveyed 65 preservice secondary mathematics teachers who are in bachelor program and post-bachelor program for teacher certificate by using a questionnaire suggested by Sirotic and Zazkis(2007). The results of this study suggest that 83.1% of the participants gave correct answers in definitions of irrational numbers. 43% of the preservice secondary teachers gave correct answers in adding with irrational numbers. Also 91% of the preservice teachers gave correct answers in multiplying irrational numbers. The preservice teachers appeared to understand irrational numbers and operations at formal dimension. More than half of the preservice teachers gave incorrect answers in adding irrational numbers and a few participants gave incorrect in multiplying irrational numbers. The preservice teachers seemed to understand irrational numbers and operations at intuitive or instrumental dimension. The results also suggest that the preservice secondary mathematics teachers have incorrect understanding about irrational numbers.

• Journal of the Korean Geotechnical Society
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• v.28 no.10
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• pp.27-40
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• 2012

In the design of a piled raft, the axial resistance is offered by the raft and group piles acting on the same supporting ground soils. As a consequence, pile - soil - raft and pile - soil interactions, occurring by stress and displacement duplication with pile and raft loading conditions, act as a key element changing resistances of the raft and group piles. In this study, a series of centrifuge model tests have been performed to compare the axial behavior of group pile and raft with that of a piled raft (having 16 component piles with an array of $4{\times}4$) in sands with different relative densities. The test results revealed that the increase of settlement resistance occurs separately with settlement by group pile - soil interactions. The axial resistance of group piles (at piled raft) increases by group pile - raft (pile cap) interactions and that of raft (at piled raft) decreases by group pile - raft (pile cap) interactions.

• Journal of the Korean GEO-environmental Society
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• v.20 no.8
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• pp.5-12
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• 2019

A pile group, that consists of several piles connected by a pile cap, is used as the superstructure. The pile supports vertical and horizontal load to design the pile group, but the effect of bearing capacity of the pile cap has not considered. Various researches have been conducted to reflect the effect of bearing capacity of the pile cap in order to reduce the amount of piles in the range of the stability under the vertical load of the superstructure. However, the effect of bearing capacity under the horizontal seismic load has not been studied adequately. Therefore, a shaking table test was carried out with different-sized pile caps that support the superstructure in this study. This test was to verify the influence of the size of the pile cap in the group pile under the horizontal load. The result shows that the size of the pile cap affects to the dynamic behavior of the superstructure and the pile group. Also, the bigger size of the pile group makes the larger constraint effect of ground, and it results that both the ground and the pile moves as a whole.

• 한국벤처창업학회:학술대회논문집
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• 2020.06a
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• pp.45-50
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• 2020

최근 계획된 행동이론을 바탕으로 국내 증권형 크라우드펀딩 투자자의 참여의도와 무리행동에 관한 연구를 수행하였다. 연구 결과 계획된 행동이론의 주요변인 중 태도와 주관적 규범은 증권형 크라우드펀딩 투자자의 참여의도에 정(+)의 영향을 미치는 것으로 확인되었다. 그리고 간접효과 분석 결과 참여의도는 태도, 주관적 규범과 무리행동 사이에서 매개적 역할을 하는 것으로 확인되었다. 그러나 계획된 행동이론에서 행동의도의 주요 변인으로 제시된 지각된 행동통제는 참여의도에 미치는 영향이 통계적으로 비유의적인 것으로 나타났다. 대신 무리행동에는 직접적으로 정(+)의 영향을 미치는 것으로 확인되었다. 한편 국내 증권형 크라우드펀딩 투자자는 실제 투자행동을 할 때 플랫폼에서 제공되는 펀딩 진행정보를 일종의 신호로 보고 다수의 다른 투자자를 모방하여 무리행동을 한다는 것을 실증적으로 확인하였다. 본 연구는 종전 연구의 후속연구로서 국내 증권형 크라우드펀딩 투자자의 손실보전기대가 참여의도 및 무리행동에 조절적 역할을 하는지 여부를 연구해 보고자 한다. 손실보전기대는 증권형 크라우드펀딩 투자로 인해 투자자가 받게 되는 각종 혜택이나 투자조건에 따라 크라우드펀딩 투자로 인한 손실 일부 또는 전부를 보전하거나 손실 발생 가능성을 낮출 수 있다고 믿는 정도를 말한다. 본 연구를 통해 국내 증권형 크라우드펀딩 투자와 관련한 각종 혜택 및 투자조건 등이 투자자의 손실보전기대를 유발하여 투자자의 참여의도와 무리행동에 조절적 영향을 미치는지 여부를 실증적으로 확인함으로써 향후 크라우드펀딩 관계 당사자들의 동 제도 활성화 및 투자자 보호를 위한 각종 정책 및 사업계획 수립 등에 유의미한 결과로 활용될 수 있을 것이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5083-5088
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• 2010

An implementation of NPC AI(artifical intelligence) is similar with real world's flocking can increase fun factor of game. To this end, we design fish flocking patten of analyzed real world, implement using Ogre engine in this paper. To determine the usefulness of implemented fish flocking, we compare fish flocking in real world with implemented fish flocking. Implemented behavioral patterns of fish flocking show similar behavioral patterns of fish flocking in real world.