• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.529-538
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• 2016

The simplified plate theory is presented for static and free vibration analysis of power-law(P) and sigmoid(S) Functionally Graded Materials(FGM) plates. This theory considers the parabolic distribution of the transverse shear stress, and satisfies the condition that requires the transverse shear stress to be zero on the upper and lower surfaces of the plate, without the shear correction factor. The simplified plate theory uses only four unknown variables and shares strong similarities with classical plate theory(CPT) in many aspects such as stress-resultant expressions, equation of motion and boundary conditions. The material properties of the plate are assumed to vary according to the power-law and sigmoid distributions of the volume fractions of the constituents. The Hamilton's principle is used to derive the equations of motion and Winkler-Pasternak elastic foundation model is employed. The results of static and dynamic responses for a simply supported FGM plate are calculated and a comparative analysis is carried out. The results of the comparative analysis with the solutions of references show relevant and accurate results for static and free vibration problems of FGM plates. Analytical solutions for the static and free vibration problems are presented so as to reveal the effects of the power law index, elastic foundation parameter, and side-to-thickness ratio.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.365-372
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• 2016

Using the computational fluid dynamics (CFD) technique, we simulated the fluid flow in a Taylor reactor considering the aggregation and breakage of particles. We calculated the population balance equation (PBE) to determine the particle-size distribution by implementing the quadrature method-of-moment (QMOM). It was used that six moments for an initial moments, the sum of Brownian kernel and turbulent kernel for aggregation kernel, and power-law kernel for breakage kernel. We predicted the final mean particle size when the particle had various initial volume fraction values. The result showed that the mean particle size and initial growth rate increased as the initial volume fraction of the particle increased.

• Journal of the Korean GEO-environmental Society
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• v.16 no.9
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• pp.33-41
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• 2015

The vertical bearing capacity of a bucket foundation installed in sand can be calculated as sum of the skin friction and end bearing capacity. However, the current design equations are not considering the non-associated flow characteristics of sand and the reduction in the skin friction and increase in the end bearing capacity when the vertical load is applied. In this study, we perform two-dimensional axisymmetric finite element analyses following non-associated flow rule and calculate the vertical bearing capacity of circular bucket foundation of various sizes installed in sand of different friction angles. After calculating the skin friction and end bearing force at the ultimate state, design equations are derived for each. The skin friction of bucket foundation is shown significantly small compared to the end bearing capacity. Considering the difference with the available design equation for piles, it is recommended that the equation for piles is used for the bucket foundation. A new shape-depth factor ($s_q{\cdot}d_q$) for bucket foundation is recommended which also accounts for the increment of the end bearing capacity due to skin friction. Additionally, the shape and depth factor of embedded foundation proposed from the associated flow rule can overestimate the bearing capacity in sand, so it is more adequate to use the shape-depth factor proposed in this study.

• Journal of The Korean Association For Science Education
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• v.18 no.4
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• pp.473-483
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• 1998

A learner's cognitive conflict with his /her existing conception is regarded to be one of the most important factors for a conceptual change. In this study, the effects of the conflict situation types on inducing students' cognitive conflicts in Newton's law were examined. The thirty-four students of 10th grade were selected from a rural high school based on the result of pre-test. The two different types of conflict situations among many possible types were used in this study. One type was using logical conflict situation and the other was demonstrating real conflict situation. The levels of cognitive conflict were measured by 4-point Likert scale by three interviewers. As the results, the demonstration method was more effective than the logical argument method. In case of the logical argument method, rather than showing scientific conceptions, suggesting another misconception was more effective to the students who have misconception. However, logical argument method was not effective to those who have scientfic conceptions. To the students who have unscientific conceptions, the demonstration method was very effective for inducing cognitive conflict. From the results of this study, demonstration method of teaching seems to be very effective for inducing students' cognitive conflict and overcoming their misconceptions on scientific concept.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1176-1181
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• 2006

The purpose of this study was to estimate water supply analysis and reliability indicators by using allocation rule(AR) about Andong Dam and Imha Dam which have parallel reservoirs system. According to the analysis results of allocation rule, for Rule(A) and Rule(B), the contribution of water supply in Andong Dam was 60% more than in Imha Dam, and for Rule(C), the contributions in Andong Dam and Imha Dam were almost equal. In Rule(C), supply is allocated by the ratio which divides the sum of storage and inflow by the mean storage according to the storage state and supply capability state of Andong Dam and Imha Dam. This Rule(C) showed good results in the water supply capability analysis and reliability analysis of parallel reservoirs. In the analysis criteria of water supply in parallel reservoirs system, monthly water change quantity showed better results than monthly constant water quantity in water supply analysis. On the basis of this study, the new technique for water supply analysis was developed to be applied to parallel reservoirs, and this operation rule will establish the efficient operation measures in the application to several kinds of parallel reservoirs system.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.2270-2275
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• 2008

수문학적 하도추적법의 하나인 Muskingum 모형은 미 육군공병단(U.S. Army Corps of Engineers)에 의해서 미국 Ohio 주의 Muskingum 유역에 홍수조절계획으로 처음 사용되었으며 모형의 구조 및 입력자료의 단순성에 비하여 비교적 우수한 결과를 모의할 수 있는 것으로 알려져 있다. 1938년 McCarthy에 의해서 개발되었고 구간내 총저류량은 prism 저류와 wedge 저류로 구분하여 prism 저류는 유출량에 wedge 저류는 유입량과 유출량의 차에 직접 비례한다는 가정하에 추적식을 개발하였다. 이후 지속적인 연구가 이뤄져 1985년 O'Donnel은 측방유입량(lateral inflow)을 상류단의 유입량에 비례하는 형태로 3-매개변수 muskingum 모형을 제안하여 추적계수의 결정을 선형대수(linear algebra)에서 동차(homogeneous)연립방정식 해를 구하는 Cramer 법칙인 matrix 기법을 적용하였다. 본 연구에서는 홍수사상으로부터 측방유입량이 고려되고 추적계수 결정에 있어서 직접 계산이 가능한 O'Donnel(1985)이 제안한 3-매개변수 muskingum 모형을 적용하였다. 추적계수들의 결정은 직접 matrix 기법을 적용하였고 적용대상은 낙동강 유역의 낙동 지점을 상류단으로 구미 지점을 하류단으로 선정하였다. 홍수사상은 낙동강 유량측정 조사사업 2005년${\sim}$2007년 보고서에 수록된 수문자료를 선정하여 관측치와 계산치를 비교하였고 홍수사상에 적용하여 수문곡선을 추정하였으며, 각각의 매개변수가 추적구간에 어떠한 영향을 미치는지 변수간의 관계를 분석하였다. 또한, 관측치와 계산치의 적합도 검증은 평균제곱근오차(root mean squar error; RMSE)와 모형 효율성 계수(model efficiency; ME)를 산정하여 분석하였으며, 하도 구간내 저류량은 대상구간에 대한 유입량과 유출량의 가중합에 비례한다는 선형모형을 적용하였다.

• Sim-seong Yeon-gu
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• v.27 no.1_2
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• pp.1-27
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• 2012

It aims to deal with a topic of coniunctio oppositorum, hieros gamos in a Korean fairytale <Gurungdungdung Sin Seonbi>, in which a human heroine was marrying an animal husband. This Korean fairytale may be compared with Greek mythology <Eros and Psyche> introduced by Apuleius and <Dassingende springende Löweneckerchen> collected by Grimm Brothers. All these fairytales commonly tell that animal husband figures have divine nature. Because animals live their lives totally obeying instincts, the collective unconscious principles of species are completely accomplished. The animal nature excludes ecocentric attitude so that it has transpersonal divinity. The hero is transformed into an animal in the fairytales, which will provide an opportunity to change a one-sided exaggerated attitude of the ego consciousness and acquire universal humanity. During being an animal, the hero would have experienceds to recognize true meaning and value of other living creatures in nature and have attained wisdom of nature. The animal is a symbolic being who will realize value of collective and universal life so as to act therapeutically and contribute to the total personality, individuation processes. Animals in the fairytales correspond to the compensatory contents of the unconscious. Animal figure itself is opposite to the ego consciousness itself because the ego understands the unconscious contents like animal figures have instinctual impulse that the ego will not accept at all. Coniunctio oppositorum in the fairytales is going to show the ego's rendezvous processes to meet the unconscious. The fact that the hero turns into an animal or marries animal partner is a psychic event which greatly lowers under the level of ego consciousness. To overcome the state, it is essential for the hero to regain humanity or to transform animal partner into a human being. By the recovery of humanity or reaching the human level, compensation of the unconscious can be realized in the conscious life. In a Korean fairytale <Gurungdungdung Sin Seonbi>, male partner is a serpent but the heroine marries the serpent and make it cast off skin. Over sufferings and complishment of several tasks, heroine truly meets her husband. In this processes, the heroine obtains divinity. As result, her marriage to animal husband means hieros gamos. In this fairytale, we will be able to look through the ways how female ego-consciousness to make relations to the unconscious and to fulfill individuation.

• The Journal of Korean Philosophical History
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• no.56
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• pp.119-149
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• 2018

Le 樂 is important in Politics of the Kings. It is the same in Nothern Song period(北宋). There was an argument about Le 樂 and Lu 律 in Nothern Song Period. Those who argued were Fan-Jin(范鎭) and Sima-Guang(司馬光). They argued for 30 years. Fan-Jin insists that a standard of weights and measures is Lu and a standard of Lu is the fundamental tone of twelvenotes scale, Hwang-Jong 黃鍾. On the other hand, Sima-Guang insists that a standard of Lu is weights and measures and a standard of Le is Equilibrium and Harmony, Zonghe 中和. Fan-Jin thinks it is possible to restore a Sage King's music through the right standard of Lu. But Sima-Guang thinks it is impossible. Sima-Guang believes that the only way to restore a Sage King's music is to complete Zonghe. And Fan-Jin thinks Zonghe is the work of the king whereas Sima-Guang thinks Zonghe is the order of man and everything. The key point in the argument is Lu and Zonghe. Fan-Jin regards Lu as the basis of music, whereas Sima-Guang regards Zonghe as the basis of music. Lu is a tangible law and Zonghe is a intangible law. Although the argument between the two ended in a stalemate, the argument shows the difference between the scholars at the time.

• Journal of the Korean association of regional geographers
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• v.8 no.2
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• pp.184-198
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• 2002

Since the mid-1980s there has been an intensive debate on a regional geography in abroad, and its renaissance has been widely expressed. Under the influences of these academic circumstances, many Korean scholars have tried to introduce this trend and at the same time to propose new development lines of the Korean geography with a critical perspective. However, the empirical study of Korean regional geography including area studies is characterized by a quantitative deficit on the one hand and by its peripheral position on the other. The main reasons of this marginalization of Korean regional geography that we can find include a undifferentiated import of new systematic/nomothetic geography in the 1960s and 1970s, a historical interruption with a tradition of old Korean geography, and the practical difficulties of regional geographical approach itself. Now we face with the fundamental changes including globalization/regionalization and an increasing actual demand for the information on different scales of space and place. In order to cope with these challenges, we inevitably need to revitalize various forms and modem characteristics of regional geographical approaches and try to reexamine the basic concepts, methods, and frameworks of regional geography.

• Journal of The Korean Association For Science Education
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• v.34 no.8
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• pp.755-765
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• 2014

The convergence and consilience in education (hereafter, interdisciplinary education) is receiving great attention from societies. This study aims to investigate the works of scientists and artists who have intended to combine science with the arts in the modern era, to take into account the socio-philosophical setbacks during the period, and to suggest pedagogical implications of science education as interdisciplinary education. The concept of interdisciplinary education stems from Plato's thought, idea, as a comprehensive and invariant truth. The renaissance, full of enrichment about scientific achievement, was based on Neo-Platonism pursuing holistic-synthetic approach. During the time, scientists presented in this study tried to find comprehensive principles and borrow useful method from the arts. In such a context, scientists not only made use of the arts for expression of scientific knowledge, but also drew conclusion by analogical reasoning between science and the arts. Artists, as well, relied upon anatomy and optics especially, to elaborate linear perspective and even developed their own scientific knowledge through personal experience. Hence, contemporary science education should encourage students to hold a holistic viewpoint about science and the arts, articulate explicit goals and outcomes as interdisciplinary education, implement meta-disciplinary instruction about science and the arts, and develop assessment framework for collaborative learning. There may be good examples for inter-disciplinary education as listed: illustrating scientific ideas through the arts and vice versa, organizing collaborative works and evaluations criteria for them, and stressing problem solving on a daily basis.