• Journal of Elementary Mathematics Education in Korea
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• v.24 no.1
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• pp.1-30
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• 2020

This study was carried out in order to identify the error types of statistical graphs for statistical literacy education. We analyze the meaning of using graphs in statistical problem solving, and identify categories, frequencies, and contexts as the components of statistical graphs. Error types of representing categories and frequencies make statistics consumers see incorrect distributions of data by subjective point of view of statistics producers and visual illusion. Error types of providing contexts hinder the interpretation of statistical information by concealing or twisting the contexts of data. Moreover, the findings show that tasks provide standardized frame already for drawing graphs in order to avoid errors and pay attention to the process of drawing the graph rather than statistical literacy for analyzing data. We suggest some implications about statistical literacy education, ethical problems, and knowledge for teaching to be considered when teaching the statistical graph in elementary mathematics classes.

• Journal of the Korean Society for Railway
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• v.13 no.4
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• pp.382-388
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• 2010

This paper describes the standardized finite element model for carbody structures of railway vehicle made of sandwich composites. Recently, sandwich composites were widely used to railway vehicle due to the improvement of energy efficiency, high specific stiffness and strength, weight reduction and space saving in korea. Therefore, structural integrity should be verified using finite element analysis prior to the manufacture of composite railway vehicle. The standardized finite element model for composite carbody structures was introduced through comparing the results of real structural test under vertical, compressive, twisting load and natural frequency test of various railway vehicles in this study. The results show that the quadratic shell element is suitable to model the reinforced metal frame used to improve the flexural stiffness of sandwich panel compared to beam element, and layered shell and solid element are recommended to model the skin and honeycomb core of sandwich panel compared to sandwich shell element. Also, the proposed standard finite element model has the merit of being applied to crashworthiness problem without modifications of finite element model.

• Journal of the Korean Wood Science and Technology
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• v.28 no.3
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• pp.14-24
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• 2000

In present research, the plywoods made of radiata pine or Japanese larch, the potential softwood species in mass supply, were discussed to examine their feasibility as the structural and concrete form panels through the basic properties test. First, plywood qualities and its nail performance were tested. The performance test for concrete form or structural panel by concentrated and uniformly distributed load were conducted to investigate the possibility as structural material for light frame and concrete constructions. Test results of basic quality such as specific gravity, cupping, bowing, and twisting appeared to satisfy the criteria for structural use. Also, nail performance test results, for roof and wall sheathing panels, nail lateral resistance, nail withdrawal resistance, and nail push head resistance proved to meet the required standard for structural use. The test results on performance as structural panel by concentrated and uniformly distributed load and as concrete form panel showed that these two species could be used for structural sheathing, subfloor, and concrete form panels.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.84-91
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• 2022

This study investigated the behavior of out-of-plane skewed moment connections that were designed as IMFs, as per the Korean standards. A total of 14 finite element models were constructed with the consideration of two types (single- and double-sided connections) and four levels of skew angle (0°, 10°, 20°, and 30°). The results indicated that the skewed connections considered in this study met the acceptance criteria for IMFs given by the codes. However, the load-carrying capacities of skewed connections were decreased as the skew angle increased. For the connection with a skew angle of 30°, the peak load was noted to be 13% less and the energy dissipation capacity could be 26% less than that of non-skewed connection. In addition, because of the skewed nature, the stress distribution in the skewed beam flange near the connection was asymmetric and the stresses were concentrated on the beam inner flange. Column twisting induced by the skewed configuration was very small and negligible in the beam and column combination considered in this study.

• Journal of Conservation Science
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• v.34 no.5
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• pp.319-331
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• 2018

The collection of the National Museum of Modern and Contemporary Art, Korea, features a sansu folding screen that was created in 1940 to commemorate the sixtieth birthday of Soseok Kang Jin-Koo. It was created by six oriental painters, who were among the ten best painters in that era. The folding screen has been previously repaired and restored; however, owing to damage such as twisting of its wooden frame, abrasion, and moisture stains, rigorous conservation treatment is required. Hence, scientific research was conducted to analyze the textile, paper and pigments employed while creating the folding screen, to identify the associated material properties. Results showed that the textile used in the screen's picture and janghwang comprise synthetic fibers and natural fibers such as cotton and silk. Various types of papers were used in the folding screen, such as those from mulberry, herbaceous, and coniferous fibers. Furthermore, calcite deposits were found on the base of every picture, and certain colors employed by the artists appear to be produced from different pigments.