• Journal of the Korean Geographical Society
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• v.31 no.2
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• pp.268-294
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• 1996

Social and population geography in Korea has been developed somewhat later than other special subjects of geography. But in recent years, it has attracted much interests of geographers, and accumulated a considerably large amount of research products. Seen in this context, it is resonable to expect that social and population geography will not only lead the development of geography in the future, but also contribute to the resolution of socio-spatial problems in Korea. From this point of view, we shall retrospect in this paper the progress of social and population geography in Korea since the 1950s, and look out its future prospect and further research tasks. In the first place, we discuss general concepts and major themes of social and population geography, and overview its development process, and than review in more details some important research products which would be categorized into five main subjects, that is, research methodology, urbanization and urban population phenomena, population movement and changing rural life, residential differentiation and urban redevelopment, and urban social life and regional social well-being. Finally, we consider briefly the future prospect and further tasks of social and population geography in Korea.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.3 no.1
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• pp.117-128
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• 1992

For many years, a number of critical issues have been raised in relation to classification criteria. prevalence and clinical features as well as the concept of childhood depression itself. In order to achieve a better understanding of the childhood depression, empirical data on the prevalence and clinical features of depression in childhood and adolescence were reviewed and discussed from the developmental perspective. The developmental perspective proposes that maladaptive behaviors are products of the coping process to normal developmental tasks and it is necessary to make out the normative and adaptive developmental process in order to understand maladaptive behaviors. Age associated changes in depression symptomatology were discussed in relation to cognitive and socio-emotional development and directions for future research in childhood depression were suggested.

• School Mathematics
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• v.12 no.2
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• pp.239-257
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• 2010

In school mathematics the derivative concept is intuitively taught with the tangents and the concept of instantaneous velocity. In this paper, I investigated the long historical developments of the derivative concepts and analysed the relationships between the definition of derivative and the related elements. Finally I proposed some educational implications based on the analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3541-3546
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• 2011

Autophagy is an evolutionarily conserved lysosomal pathway for degrading cytoplasmic proteins, macromolecules, and organelles in addition to recycling protein and ATP synthesis. Although autophagy is very important during embryogenesis, the mechanism underlying the dynamic development during this process remains largely unknown. In order to obtain insights into autophagy in early embryo development, we analyzed gene expression levels of autophagy-related genes (ATGs) in mouse embryos developing in vitro. Using real time RT-PCR technique, ATGs including Atg2a, Atg3, Atg4b, Atg5, Atg6, Atg7, Atg9a, and Wipi3, as maternal transcripts, were only up-regulated in 1-cell embryo stage before zygotic genomic activation (ZGA), and then expression decreased from 2-cell to blastocyst embryo stage. ATGs including Dram and Atg9b were expressed abundantly in 1-cell embryo state and in blastocyst embryo stage, athough Atg8 and Ulk1 were constantly expressed during preimplantation stage. However, Atg4d were only up-expressed from 4-cell to blastocyst stage. These results suggest that autophagy is related in mouse embryo, which possibly gives an important role for early development.

• Journal of The Korean Association For Science Education
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• v.36 no.2
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• pp.295-302
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• 2016

In this study, we investigated a learning progression focusing on $5^{th}$ to $9^{th}$ graders' performances with dissolution and solution concepts using the construct modeling approach. We designed a construct map describing hypothetical pathways of the concept development of dissolution and solution by analyzing both National Science Curricula and related studies. A conceptions test consisting of ordered multiple-choice items was developed and administered to 826 students. A revised construct map was derived from analyses of the results based on the partial credit model, a branch of polytomous item response theory. The sequence of dissolution and solution concepts presented in the current science curriculum was found to correspond with the learning progression of the students. However, the lower anchor, the concept of the homogeneity of particles in solution, and the factors affecting solubility were not consistent with the expected levels of the construct map. After revising the construct map, we proposed a learning progression for dissolution and solution concepts with five levels: Students of level 1 (the lower anchor) recognize the particles in the solution but misunderstand various concepts; Students of level 2 understand the homogeneity of particles in solution; Students of level 3 understand solubility and the conservation of particles during dissolution; Students of level 4 partially understand the interaction between particles; and Students of level 5 (the upper anchor) understand the interaction between particles and the factors affecting solubility.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.8
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• pp.839-847
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• 2012

Numerical simulations for channel flows with $Re_{\tau}$ = 180, 395 and 590 have been performed to investigate the hairpin packet formation process in wall-bounded turbulent flows. Using direct numerical simulation databases, the initial flow fields are given by the conditionally averaged flow field with the second quadrant event specified at the buffer layer. By tracking the initial vortex development, the change in the initial vortex to an ${\Omega}$-shaped vortex and th generation of a secondary hairpin vortex were found to occur with time scales based on the wall units. In addition, at the time when the initial vortex has grown to the channel center, the inclination angle of the hairpin vortex packet is approximately $12{\sim}14^{\circ}$, which is similar for all three Reynolds numbers. Finally, numerical simulations of the evolution of two adjacent hairpin vortices have been performed to examine the interaction between the adjacent vortex packets.

• Journal of Educational Research in Mathematics
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• v.26 no.4
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• pp.683-700
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• 2016

The traditional teaching-learning in mathematics, which pursue only one correct answer, should be reexamined to cope with an age of uncertainty. In this research, Perry's epistemological development scheme was noticed as a theoretical approach to diagnose problems of dualistic mathematics lessons and to search solutions of the problems. And Design-Based Research method was adopted, We developed the epistemological development scheme through considering Perry's theory and related studies, scaffoldings and teaching-learning to enhance students' epistemological positions in mathematics. Based on these discussions we designed teaching experiment about operations with negative numbers, and analyzed its didactic implications.

• Environmental Analysis Health and Toxicology
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• v.19 no.1
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• pp.73-80
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• 2004

숭어의 생식주기를 밝히기 위해 2002년 2월부터 2003년 3월까지 제주도 동남부 연안에서 채집하였고, 난모세포의 발달과정을 조직학적 방법으로 관찰하였다. 난모세포의 발달과정은 GSI변화와 밀접하였다. GSI는 9월에 급격히 증가하여 12월에 최고 값을 나타내었다. 난소의 조직학적 관찰결과, 염색인기와 주변인기의 난모세포는 연중 관찰되었으며,8월에는 일부에서 난황을 포함하는 난모세포가 관찰되었다. 대부분의 난모세포가 10월과 12월에는 난황구기 단계의 난모세포로 발달했다. 10월과 12월에 난황구기 난모세포들을 가진 개체의 출현이 가장 높았으며, 잔존여포와 퇴화 난모세포는 2월부터 관찰되었다. 숭어의 주 산란기는 11월에서 1월이고, 난군동기발달형의 난소를 가지며 외양으로 이동하여 산란하는 어류에 속한다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.3
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• pp.26-36
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• 2003

Collected and analyzed the coastal processes at the estuary of Nak-Dong river and its near coastal area from the history of field measurements. Introduced a numerical model to predict three dimensional topographical change which are evaluated from the nearshore wave and the wave induced current fields for the objective area, and later it were related to the development of beach and shoals. With the comparison between measured and calculated, we found that the changes on the coastline and sand spit and bar development are induced not only by artificial forces due to the construction of river dike, but also by the strong impact of wave induced current. In future days, it is expected that coastline change and sand bar development at the lee side of Jinwoo-Deung and at the front of Dadae beach.

• School Mathematics
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• v.11 no.4
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• pp.745-771
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• 2009

To acquire the hints of the development of children's multiplication strategies, this study tried to find the differences between the students who learned multiplication and the students who didn't. And we also tried to explore their acquired computational resources. As a result, we confirm that there is a certain direction on the development of children's multiplication strategies according to their grades and the level of acquirement of mathematical knowledge. Moreover, we comprehend that commutative law is an important part of the strategies on two-digit multiplication and that acquisition of the computational resources must precede the learning of multiplication strategies. In the end part, this article proposes a new taxonomy of strategies for multiplication. To support our proposal, we integrated the prior researches with our findings.