• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.109-110
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• 2018

Preloading Strut applied during installation of the wall jack, but additionally serves to minimize the displacement of soil pressure acting upon dissolution due to the difficulty. In this study, we developed an index of support for the release of stress to facilitate the dismantling of the strut uninstall. The refractive support the axial force acting on the strut are supportable, is refracted at minimum load, disassembly should be easy. In order to find the optimal shape and structural stability of the refractive support We have performed the numerical analysis and performance test to determine the final model. We carried out model tests and UTM test in order to understand the refractive performance and durability of the refractive support for optimal model. Results of the test UTM is refracted all shot 5 times within a target hit number, it was found that there is no problem of the refractive performance. Further, the results of model experiments, it was found that to ensure sufficient durability more than the performance target value of the pin joint support structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.435-442
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• 2017

A catadioptric optical system produces images by refraction and reflection. To improve the image quality, the shape of the secondary mirror supporters should be determined to ensure that the centering error and tilt of secondary mirror are very small, and the main mirror receives the maximum amount of light. Furthermore, random acceleration vibration has a severe effect on the optical system for observation reconnaissance. In order to obtain the best design under these circumstances, the volume of the secondary mirror supporter must be minimized while satisfying the constraints expressed in standard deviations of the centering error and tilt. It is difficult to analytically calculate the design sensitivities of the standard deviations, because they are statistically defined. Hence, after their second-order regression equations were determined using a response surface methodology, an optimal geometric design was obtained. As a result, it was found that the method proposed in this paper, which included a random vibration analysis, was effective in obtaining the optimal design for a secondary mirror supporter with robustness.

• Korean Journal of Cognitive Science
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• v.24 no.3
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• pp.203-235
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• 2013

The goal of this paper is to test the findings about English-speaking children's acquisition of inflectional morphemes in the literature using a large-scale database. For this, we obtained a 4.7-million-word corpus from the CHILDES (Child Language Data Exchange System) database, and analyzed 1,630 British and American children's uses of English derivational morphemes up to age 7. We analyzed the type and token frequencies, type per token ratio (TTR), and the lexical diversity (D) for such inflectional morphemes as the present progressive -ing, the past tense -(e)d, the comparative and superlative -er/est with reference to children's nationality and age groups. To sum up our findings, the correlations between the D value and children's age varied from morpheme to morpheme; e.g. we found no correlation for -ing, a marginal correlation for -ed, and a strong correlation for -er/-est. Our findings are consistent with Brown's (1973) classical observation that children learn progressive forms earlier than the past tense marker. In addition, overgeneralization errors were frequently found for -ed, but rarely for -ing, showing a U-shaped developmental pattern at ages 2-3. Finally, American children showed higher D scores than British children, which showed that American children used inflectional morphemes for more word types compared with British children. The present study has its significance in testing the earlier findings in the literature by setting up well-defined methodology for analyzing the entire CHILDES database.