• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6A
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• pp.525-534
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• 2010

A road curbstone is a structure installed at the boundary of the sidewalk and the street with the objectives of road drainage, drawing attention and such. The current general construction method of curbstones places foundation concrete for the curbstones first, waits until the concrete reaches the strength to support the curbstones, places the curbstones on top, and then places the gutter and rear filling concrete. Such method has the issues of poor compaction and weakened bond strength of concrete due to split placing of concrete, and causes the curbstones to easily separate due to vehicle impact or earth pressure, in turn creating maintenance costs and spoiling the aesthetics. To improve such conventional construction methods, an all-in-one method was developed using formwork rail and jig where both the curbstones and gutter can be worked at the same time, and to evaluate the structural performance, static tests of lateral loading test, pullout test, and bending test were executed, and dynamic tests such as pendulum test and actual vehicle impact test were executed. In all tests, the all-in-one construction method using formwork rail and jig was shown to be superior to the conventional construction method by the increase of construction quality and bond strength of concrete.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.31-40
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• 2017

Absolute nodal coordinate formulation was developed in the mid-1990s, and is used in the flexible dynamic analysis. In the process of deriving the equation of motion, if the order of polynomial referring to the displacement field increases, then the degrees of freedom increase, as well as the analysis time increases. Therefore, in this study, the primary objective was to reduce the analysis time by transforming the dimensional equation of motion to a non-dimensional equation of motion. After the shape function was rearranged to be non-dimensional and the nodal coordinate was rearranged to be in length dimension, the non-dimensional mass matrix, stiffness matrix, and conservative force was derived from the non-dimensional variables. The verification and efficiency of this non-dimensional equation of motion was performed using two examples; cantilever beam which has the exact solution about static deflection and flexible pendulum.

• Journal of The Korean Association For Science Education
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• v.33 no.2
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• pp.405-424
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• 2013

The purpose of this study is to explore the characteristics of secondary science teachers' thoughts on 'good' science teaching and to find a concept that can represent the way the teachers think. Participants were twenty pre- and in-service teachers who were enrolled in a graduate course I taught at a university located in Seoul in the first semester, 2011. The participating teachers collected and analyzed a variety of data and created portfolios while they were trained, as part of the course, on qualitative research methods with the same research questions as those of this study. In the current study, the process in which the teachers and I found answers to the research questions was narratively reconstructed based on the teachers' portfolios and my field notes. It was revealed that science teaching was perceived as a task aiming at realizing some kind of values and that because the teachers pursued various values in the science classroom and there exist conflicting relationships among different values, it was hard to define 'good' science teaching. It was also discussed that science instruction was inherently accompanied with the ongoing process of selecting values as the relationships among the values were ever-changing within the contexts of the classroom. This multi-faceted and dynamic structure of the teachers' thoughts on 'good' science teaching was conceptualized analogically as 'Foucault's pendulum,' which has multiple planes of oscillation. Implications for science teacher education and science education research were suggested.

• Journal of the Korean Geographical Society
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• v.28 no.2
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• pp.163-178
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• 1993

The purpose of this paper is to provide a better understanding of the unprecedented reform movement of geographic education in the United States since 1980 and extract some implications from this movement for geographic education in Korea. For the purpose, the history to this movement was reviewed through following three stages. In the first stage(1980~1984: form :HSGP" to :"Guideline"), the voluntary improvement movement appeared at California and the orgni-zational movement began in 1982 such as the Committee on Geography and International Knowledge. The national educational refrom imperatives, presented at "A Nation at Risk", and "Back to Basics" movement provided good opportunities to resurrect geography as a basic subject. For next real resurrection movement, the very important document "Guidelines for Geographic Education" was published at 1984. In the second stage(1985~1989: from "Guide-lines" to "Public"), the "Guideline" gave power-full motives and foci for reconstructiong the contents of geography, especially by the five fundamental themes(Location, Place, Relation-ships within Places, Movement, and Region). Also GENIP as the symbol of unity of all four major geography organization(AAG, NCGE, NGS, AGS) contributed to expanding and stren-gthening geography education. Also Geography Educagtion Program of NGS was a smart and well organized program to improve geographic education through it's a five strategies: Grass-roots organization(Alliances), Teacher education, Pu-blic awareness, Educational materials develo-pment, Targeted outreach to education decision-makers. In the late 1980s, the last focus of movement was the Public awareness and Edua-ction decision-making. In the third stage(1990-present: from "Public" to "Core Subject"), the initiative pendulum swung from geography organization to nation curricu-lum. In this National Curriculum, Geography was approved as a "Core Subject" and The 1994 National Geography Assessment Framework was constructed to assess the outcome of student's education in geography in grades, 4,8, and 12. Some Implications extracted from the process and contents of renaissance movement of geogr-aphic education in the Uinted States since 1980 are as follows. First, It shows the importance of the unity and target assignment among the geography organization. Second, interactive relationship between the academic geography and school geography develops each other. Third, teacher education, including pre-service education, including pre-service education and in-service education, is a key element to improve the quality of geography. And teacher organization is a good clearing house to exchange information for good geography. Forth, the positive and active response to changes in socketies such as globalism and inter-nationalizing, national education policy, and the trend of pedagogy is needed to rejuvenate geo-graphic education. Above all, we need to establish a well organized and powerfull program, sophisticated activities strategies, and long-term implementa-tion plan if we want more and better school geography.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.28-44
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• 1998

This study was conducted to suggest the ecological restoration strategies for the disturbed landscapes by theoretical study. Especially, it is aimed to suggest three objectives for restoration by using native plants ; (1) prevention or reduction of wind and water erosion, (2) provision of food and cover for variety of animal species, (3) improvement of the visual or aesthetic quality of disturbed sites. The main results were summarized as follows. 1. Cooperation between restoration ecologists and restoration practitioners is needed to delineate a scientific approach to restoration ; (1) Being aware of published literature that describes similar work and/or establish general principles. (2) Preparedness to carry out proper experiments to test ideas. (3) Preparedness to monitor fundamental parameters in a restoration scheme. (4) Providing information about the behavior of species. (5) Publish results. 2. There are three models of succession in theories of plant succession. The tolerance and facilitation models were recommended to ecological restoration. The inhibition model applies in most secondary succession, but the actual species which are introduced first may inhibit the germination and growth of slower-growing species, or they may prevent the growth of other species whose propagules arrive later. 3. The objectives of erosion control, wildlife habitat provision, and visual quality improvement are not mutually exclusive. However, many revegetation practices in the past have emphasized one of these aspects at the expense of the others. 4. A native plant community can be the model of ecological restoration. By stylization/abstraction of native plant community, trying to learn the most essential characteristics of community types - environmental factors ; dominant, prevalent, and "visual essence" species composition - in order to use such information in restoration. 5. After developing mass/spaces plan, match plant communities to the mass/space plan. In utilizing community grouping, there needs aesthetic ability to understand design elements. 6. Several hydrophytes such as Pennisetum saccharifluous, Themeda triandra, Cirsium pendulum show relatively good germination rates. In case of mesophytes and xerophytes, Arundinella hina, Artemisia princeps, Oenothera odorata and legumes seem to have quick-germinating abilities at barren sites. Pinus thunbergii, Rhus chinensis, Evodia daniellii, Alnus firma and Albizzia julibrissin can be considered as "late succession" woody plants because they show low germinating rates and slow growing habitat. 7. The seeds used for restoration should be collected within a certain radius of where it will be planted. Consideration in genetic issues in the collection and use of germplasm can increase the odds for successful restoration efforts. 8. The useful model in the "drift" pattern occurs so abundantly in naturally evolving landscapes. As one species diminishes in density, a second or third species are increased. Thus, dynamic interactions between species are created. Careful using of "drift phenomenon" in planting was recommended. 9. Virtually no stand of vegetation today is immune from the introduction and/or spreading of exotic species. Therefore, the perpetuation of a restored sites requires conscious monitoring and management. Thus, management would be the most important process in ecological restoration. 10. In order to keep the sites "natural", alternative management strategies would be applied in management ; Atenative management strategies are decelerating successional process, accelerating successional processes or modifying species composition. As management tools, mechanical, chemical, biological or environmental factor manipulation, e.g., fire could be used.