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        검색결과 5,022

        701.
        2019.10 구독 인증기관 무료, 개인회원 유료
        3,000원
        704.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Safety-related cabinets and their electrical parts, such as relays and switches in nuclear power plants, should maintain continuous functioning, as well as structural safety according to the nuclear regulatory guidelines. Generally, an electrical part is qualified if its functioning is maintained without abnormality during excitement by motion compatible with the test response spectrum, which is larger than its in-cabinet response spectrum (ICRS). ICRS can be determined by shake-table test or dynamic analysis. Since existing cabinets in use can hardly be stopped and moved, dynamic analysis is preferred over shake-table test in determining ICRS. The simple method, suggested by the Electric Power Research Institute (EPRI) to determine ICRS, yields conservative or non-conservative results from time to time. In order to determine that the ICRS is better than EPRI method in a simple way, Ritz method considering global and local plate behaviors was suggested by Gupta et al. In this paper, the Ritz method is modified in order to consider the rocking and frame behaviors simultaneously, and it is applied to a simple numerical example for verification. ICRS is determined by Ritz method and compared with the results by finite element method (FEM). Based on this numerical example, recommendations for using Ritz method are suggested.
        4,000원
        705.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to investigate the effect of different feed inoculation method on rumen fermentation in an in vitro. Three experimental treatments were used: control (CON, direct dispersion of feed (2 g) in rumen fluid), combinations of direct dispersion (1 g) and nylon bag (DNB, pore size: 50 μm, 1 g), and nylon bag (NB, 2 g). An in vitro fermentation experiment was carried out using strained rumen fluid for 48 h incubation time and timothy was used as a substrate. At the end of the incubation, in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), pH, volatile fatty acids (VFA), ammonia nitrogen (NH3-N), and microbial community were evaluated and gas production was estimated at 3, 6, 12, 24, 48 h incubation periods. Gas production was higher in CON than DNB and NB at 6 and 12 h incubation time (p<0.01). There were no differences in final gas production, pH, NH3-N concentration, total VFA production, and VFA profiles among treatments. The IVDMD was lowest in CON (p<0.01) but the IVNDFD was not differed by feed distribution methods. There were no significant differences in general bacteria and fungi. Protozoa count was highest in NB treatment among treatments (p<0.01). The abundance of cellulolytic bacteria, Ruminococcus flavefaciens and Fibrobacter succinogenes, was highest in the CON among treatments (p<0.01).
        4,000원
        706.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Given the view of tests as mechanisms within a language policy framework (Shohamy, 2006), Korean proficiency tests are not only used as a way to measure language knowledge, but rather as tools to impose national ideologies about langage use and diversity. The field of Korean language testing needs to embrace sociopolitical dimensions, and engage what is going on value and consequence in test development and validation. By drawing upon a combined approach of Messick’s (1989) validity framework, Fairclough’s (2001) Critical Discourse Analysis (CDA), Bachman and Palmer’s Assessment Use Arugment (AUA), this study aims to illustrate how the practice of testing can be discursively interpreted as a multilayered phenomenon, constituted through discourse. It discussed the applicability of AUA’s two claims (decisions, consequences) to the validation of Korean language proficiency or related certification testing for immigrants with foci of value implications and consequences. The interconnectedness of test validation and CDA is modelled through the procedure of Faircough’s (2001) analytic methodology. In an effort to illustrate that language testing is discursively value-laded, this study not only offer a theoretical and methodological addition to the current inquiry of test validation, but also re-emphasize that language testing is sociopolitically driven from a discursive angle.
        6,600원
        719.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study deals with the design of the Stewart platform for an efficient 6 Degrees of Freedom (DOF) motion of a ship. The general methods of study of the Stewart platform – forward and inverse kinematics – are complex in nature, and are only applicable in limited and specific cases. In order to study the reduction of design time of the Stewart platform, the (please write the full form) DMU module supported by 3D CAD is used. The results show that the DMU module can easily identify the Stewart platform's clash and movements. In addition, it was also possible to calculate motor control data necessary for the prototype manufacturing process. Comparing the Upper plate angle displacement error of the prototype and the DMU results, the error range was found to be 1.5%.
        4,000원
        720.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examines the domestic and international bulletproof test standards of armor and plate which are supplied to the domestic market. In addition, improvements and suggestions for the test standard were presented. Experiments were conducted to clarify the distances to the edge, the difference between ammunition makers, and the position of the impact point of the bulletproof plate, which have been discussed in the conventional bulletproof test. As a result of the study, it was confirmed that the bulletproof performance is excellent as the distance from the edge increases. Next, performance differences between ammunition makers were not found. Finally, plates should be applied to the US ESAPI test specification to provide a clear and reproducible test method.
        4,000원