• International Journal of Highway Engineering
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• v.9 no.4
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• pp.193-204
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• 2007

Deformation strength($S_D$) is a property which shows relatively good correlation with rut resistance of asphalt mixtures at high temperature. The Asphalt Pavement Analyzer (APA) is widely used as an equipment for estimating rut resistance of asphalt mixtures. The APA was used as corresponding property of the $S_D$ to estimate rutting resistance of asphalt mixtures. Many data were collected to establish the correlation of $S_D$ with APA. For $S_D$ test, the specimen is submerged into the $60^{\circ}C$ water for 30 minutes before applying a vertical load at the speed of 50mm/min to obtain peak load (P) and deformation (y) for $S_D$ calculation. For the same materials, APA test was performed. Relation of the $S_D$ with APA rut depth was evaluated using regression analysis. The $R^2$ value was 0.76, indicating this simple test procedure being a possible method for predicting deformation resistance of asphalt concretes at high temperature. It was also shown that, using the regression model, minimum value(s) of $S_D$ of surface course asphalt mixture or binder course for a particular road level can be determined. The limit values may be possible to use as cut-off value(s) of asphalt mixtures for the layer after further elaborated studies.

• Review of Culture and Economy
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• v.21 no.1
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• pp.85-104
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• 2018

The studies related to the price of artworks have focused on how factors that are determined on production level, such as artists and the artwork materials of the studies, affect the artwork prices. As 'Dansekhwa' is in the spotlight within local Korean art auction matket, this study would like to analyze the trend of the price changes of 'Dansekhwa' with its growing popularity among the public. We have estimated the price changes based on 4,199 auction data of 20 artists with top 20 auction prices selected by the Korean Art Price Appraisal Association, between 2005 and 2016. Also, in order to compare and analyze the price changes of the 'Dansekhwa' products, we have classified the 20 artists into groups of Dansekhwa and non-Dansekhwa. Starting from 2013, when Dansekhwa has first appeared, we applied the Difference in the Difference model(DiD) to estimate the result. As a result, the difference between two groups showed 71% of price difference due to the increase in popularity of Dansekhwa. This result proves that recognition level has an important role for increase in price of an artwork. Moreover, the fact that the formalized style of Dansekhwa has linked to the appreciation of the price means that production of information could play an essential role in growth of art market. As recognition level of Korean artists and their artworks is considerably low within the local art market, putting in the effort to increase the popularity of artworks among the public might be a helpful way to magnify the potential demand.

• Journal of The Korean Association For Science Education
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• v.39 no.4
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• pp.499-510
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• 2019

History and philosophy of science has been consistently emphasized in science education for various purposes. In accordance with the introduction of the 2015 revised curriculum, history of science could be implemented for the curriculum; designing well-organized learning strategies is required. This study examines the case of undergraduate students who solved the convergence problem based on history and philosophy of science in the problem-based learning program. In particular, this study tries to find strategies for integrated education by comparing the problem structuring process and the meaning of problem solving experience of science/engineering and humanities/social sciences students. Participants were three students majoring in science/engineering and humanities/social sciences. Participants constructed and solved their own convergence problems by integrating the domains that were familiar to them into history and philosophy of science. While the process of structuring the problems and the use of history and philosophy of science were similar, there were differences between the science/engineering and humanities/social sciences students' point of view on history and philosophy of science and the other domain which they choose. Moreover, there were differences between the two group's meanings of problem solving experience. Finally, based on the results of this study, history and philosophy in science provided some implications in the context of science education and integrated education.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.39-52
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• 2018

The Seosan-Daesan Port is a representative trade port in Chungnam, and has the sixth largest total cargo throughput and the third largest oil cargo throughput in Korea. However, research on this port's development is lacking relative to that for Busan Port, Incheon Port, and Gwangyang Port, and no study exists that suggests the direction of the development strategy for Seosan-Daesan Port. This study discusses the future role of Seosan-Daesan Port in preparation for a rapidly changing future and the development strategy that should be established. Using the AHP, a development strategy is provided for Seosan-Daesan Port from short/mid-term and long-term viewpoints for three aspects: operation activation, infrastructure construction, and policy support. Operation activation is chosen as the most significant factor from a short/mid-term viewpoint, whereas infrastructure construction is recognized as important from a long-term viewpoint. Specifically, from a short/mid-term viewpoint, sustainable container cargo attraction, multipurpose dock construction, management pier construction, and opening of international passenger ferry lines are important factors while from the long-term viewpoint, hinterland construction, petrochemical industry cluster construction, automobile industry cluster construction, and management improvement system are important. Establishing action plans for each strategy and a cooperative network for sharing goals and strengthening cooperation is necessary.

• Journal of Korea Water Resources Association
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• v.54 no.12
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• pp.1295-1304
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• 2021

For the efficient use and management of water resources, a reliable rainfall-runoff analysis is necessary. Still, continuous hydrological data and rainfall-runoff data are insufficient to secure through measurements and models. In particular, as part of the reasonable improvement of a rainfall-runoff model in the case of an ungauged watershed, regionalization is being used to transfer the parameters necessary for the model application to the ungauged watershed. In this study, the GR4J model was selected, and the SCEM-UA method was used to optimize parameters. The rainfall-runoff model for the analysis of the correlation between watershed characteristics and parameters obtained through the model was regionalized by the Copula function, and rainfall-runoff analysis with the regionalized parameters was performed on the ungauged watershed. In the process, the intermediate state variables of the rainfall-runoff model were extracted, and the correlation analysis between water level and the ground water level was investigated. Furthermore, in the process of rainfall-runoff analysis, the Standardized State variable Drought Index (SSDI) was calculated by calculating and indexing the state variables of the GR4J model. and the calculated SSDI was compared with the standardized Precipitation index (SPI), and the hydrological suitability evaluation of the drought index was performed to confirm the possibility of drought monitoring and application in the ungauged watershed.

• Journal of vocational education research
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• v.37 no.4
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• pp.1-22
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• 2018

The study tried to investigate the school curriculum organization and teacher's perceptions about test subjects in vocational education division of the college scholastic ability test based in the 2015 revised national curriculum. This study asked vocational teachers to fill in basic questionnaire that consists of 9 relevant and subjective items for the school curriculum organization and test subjects in vocational education division of the college scholastic ability test based in the 2015 revised national curriculum. For this, the survey was conducted 58 schools of 92 schools in technical specialized high schools, meister high schools and vocational high schools about test subjects of 2015 revised national curriculum. As a result, the 'Successful career life' subject was 53.5%, the most organized in the first grade. 'test course 1' was 55.2% and 'test course 2' was 72.4% the most organized in the first grade. The Opinions on the test courses were the highest in the two subjects in the same series as the present. The teacher's perceptions showed that the current test subjects in vocational education division of the college scholastic ability test are valid. The most important factor affecting difficulty was 'The Ministry Education's policy' in vocational education division of the college scholastic ability test.

• The Journal of Korean Association of Computer Education
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• v.22 no.2
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• pp.1-9
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• 2019

In order to improve the quality of textbooks, this study analyzed seven informatics textbooks published based on the 2015 revised curriculum. Content analysis was used to analyze the organization system of these textbooks. Learning objectives of the textbooks were also analyzed according to Anderson's taxonomy of educational objectives. Furthermore, a textbook satisfaction survey, in which textbook selection criteria were applied, was given out to preliminary teachers. The results showed that the textbooks were similarly organized, centered on practice, activities, differentiated learning, and small group learning. However, the number of pages varies considerably for each chapter. After analyzing learning objectives of the textbooks, it was found that in terms of cognitive processes, 'understanding' (53%) was the highest item and 'analyzing' (16%) the second highest; in terms of type of knowledge, 'conceptual' (42%) and 'procedural' (31%) accounted for the two highest categories; in terms of cognitive domains, there has been a significant increase in 'analyzing' and 'creating' facets for learning objectives of these new versions of textbooks as compared to those of previously existed textbooks. In the satisfaction survey on a 5-point Likert scale, 'the accuracy and fairness of the content' had the highest points at 4.21 among four scale items. In this study, the improvement of the textbook is proposed based on the findings from this analysis.

• Composites Research
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• v.34 no.1
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• pp.8-15
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• 2021

In the shipbuilding and marine industry, as a technology for reducing the weight of parts to reduce energy and improve operational efficiency of ships is required, a method of applying fibers-reinforced composites which is high-strength lightweight materials, as part materials can be considered. In this study, the possibility of applying fibers-reinforced composites to the pipe support clamps was evaluated to reduce the weight of LNGC. The fibers-reinforced composites were manufactured using carbon fibers and glass fibers as reinforcing fibers. Through the computer simulation program, the properties of the reinforcing materials and the matrix materials of the composites were inversely calculated, and the performance prediction was performed according to the change in the properties of each fiber lamination pattern. In addition, the structural analysis of the clamps according to the thickness of the composites was performed through the finite element analysis program. As a result of the study, it was confirmed that attention is needed in selecting the thickness when applying the fibers-reinforced composites of the clamp for weight reduction. It is considered that it will be easy to change the shape of the structure and change the structure for weight reduction in future supplementary design.

• Journal of the Korean GEO-environmental Society
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• v.22 no.7
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• pp.13-20
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• 2021

The problem of subsidence of the roadbed near the Honam High Speed Railway, which opened in April 2015, continues to be raised, and the ground stability of the area near the Honam High Speed Railway may also be problematic. It is very important to select the factors that determine the indicators and indicators in producing the risk maps. Existing risk indicators are calculated as the final displacement volume based on the last observed date of the observed period, and time-series indicator displacement must be identified to analyze the cause of subsidence and the behavior of the indicator. Furthermore, for a wide range of regions, it is economically inefficient to conduct direct level measurements, so we wanted to observe surface displacement using SAR images. In this paper, time series indicator displacement was observed using PS-InSAR techniques, and risk was compared by rating each factor using the difference between final indicator displacement, cumulative indicator displacement, minimum displacement and maximum displacement as factors for determining risk indicators. As a result, the risk rating of the final displacement is different from that of each factor, and we propose adding factors from different perspectives in determining risk indicators. It is expected to be an important study in finding the cause of ground subsidence and finding solutions.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.595-603
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• 2020

To elucidate the structure-function relationship of polysaccharides obtained from Colocasia esculenta, the immuno-stimulating polysaccharide, CE-4a was purified to homogeneity from the crude polysaccharide (CE) extracted from the corms of C. esculenta by two subsequent column chromatographies using DEAE-Sepharose FF and Sephadex G-100, and analysis of their immuno-stimulatory activities and structure were conducted. CE-4a showed an increase in anti-complementary activity in a dose-dependent fashion. The molecular mass was estimated to be 182.4 kDa, which mainly consisted of galactose (43.5%) and mannose (18.2%). Methylation analysis indicated that CE-4a comprised at least 10 different glycosyl linkages, such as terminal Galp, 3-linked Galp, and 4-linked Manp, as well as a characteristic linkage, 2,4,6-branched Manp residue. To analyze the fine structure of CE-4a, it was sequentially digested using endo-α-(1→4)-polygalacturonase, exo-α-galactosidase and endo-β-1,4-D-mannanase. These analyses suggested that CE-4a is to be a highly branched galactomannan with a (1→4)-mannan backbone and galactopyranosyl oligosaccharide side chains.