• International Journal of Aeronautical and Space Sciences
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• v.1 no.1
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• pp.92-102
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• 2000

In this study, the 750kW medium scale composite blade for the horizontal axis wind turbine system was designed and manufactured, and it was tested and evaluated by the specific structural test rig. In the test, it was found that local bucklings at the trailing edge of the blade and excessive deflections at the blade tip were happened. In order to solve these problems, the design of blade structure was modified. After improving the design, the abrupt change of deflection at the blade tip was reduced by smooth variation of the spar thickness and the local buckling was removed by extending the web length. The modified design was analyzed by the FEM, the safety and stability of the blade structure. And Fatigue life over 20 years was confirmed by using S-N linear damage method, Spera's method, etc.

• Journal of Korean Academy of Nursing
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• v.45 no.5
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• pp.684-693
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• 2015

Purpose: This methodological study was conducted to develop and test a cultural competence scale for nursing students. Methods: Based on the five constructs of cultural competency identified in the conceptual analysis of Suh, 76 items for the tool were derived initially. These items were reduced to 58 items after content validity tests (two times) by 6 multicultural experts. Data collected from 526 nursing students were utilized to test the validity and reliability of the preliminary tool. Item analysis, factor analysis, Pearson correlation coefficients, and Cronbach's alpha were used for the analysis. Results: Twenty-seven items were selected for the final scale, and categorized into 5 factors explaining 62.1% of the total variance. Cronbach's alpha was .91 and the reliability of the subscales ranged from .76 to .91. Criterion validity between the developed tool and empathy (r=.26, p <.001) was significant. Conclusion: The results show that this scale can provide scientific and empirical data when evaluating the effectiveness of school curriculums or multicultural empowerment programs regarding cultural competence of nursing students.

• Korean Journal of Adult Nursing
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• v.27 no.3
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• pp.337-346
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• 2015

Purpose: This study was to develop and test the resilience scale for Korean nursing college students. Methods: The initial 82 items (7 factors) were developed through literature review and student interviews. Items were reduced to 55 items through content validity test by 5 experts and face validity tests by 20 nursing students. The preliminary Resilience Scale for Korean Nursing Students (RS_KNS) was administered to 302 nursing students of 4 universities in Chungnam. Data were analyzed using item analysis, factor analysis, Pearson correlation coefficients, and Cronbach's ${\alpha}$. Results: Twenty-four items were selected for the final scale. Seven factors evolved from the factor analysis, which explained 61.9% of the total variance. The internal consistency, Cronbach's ${\alpha}$ was .84 and reliability of the subscales ranged from .60 to .77. Conclusion: The resilience scale for Korean nursing college students demonstrated acceptable validity and reliability. It can be used to assess the resilience of nursing college students and is expected to get utilized in teaching and research.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.251-258
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• 2008

The use of reinforced earth walls in permanent structures is getting it's popularity. Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when subjected to repeated and/or cyclic loads, during their service period. In this investigation, the effect of preloading in reducing long term residiual deformation of back-to-back reinforced soil wall under sustained and/or repeated loading enviormentment using a series of reduced-scale model tests. It is found that the preloading technique can be an effective means of controlling residual deformations of reinforced soils under varisous loading conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.121-130
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• 2006

Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when used as part of permanent structures. In view of these concerns, time-dependant deformation characteristics of geosynthetic reinforced modular block walls under sustained loads were investigated using reduced-scale model tests. The results indicated that a sustained load can yield appreciable magnitude of residual deformation, and that the magnitude of residual deformation depends on the loading characteristic as well as reinforcement stiffness.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09b
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• pp.88-95
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• 2010

Screw piles(Helical piles and anchors) are increasingly used to support and rehabilitate reinforced structures subjected to both tensile and compressive axial loads. This study presents a variety of detailed investigation on especially pull-out characteristics of screw piles performed to both reduced scale and numerical analysis to identify fundamental failure mechanisms and empirical optimized geometry of screw piles. It was found that the pull-out characteristics of screw piles are influenced with mainly different frequencies of compaction around soil and screw pile's pitch and followings are practical data based on empirical analysis.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.328-334
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• 1998

The characteristic tests for the reduced-scale lead rubber bearings are performed with three different diameters of lead plugs. The test frequencies are 0.05Hz and 0.5Hz of the sinusoidal waves. The roles of lead plugs in the behavior of lead rubber bearings are investigated. The shear-deformation characteristic values such as stiffness, damping and yield load values are increased according to the increase of the diameter of lead plugs. The high damping value can be obtained by increasing the diameter of lead plug.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2477-2487
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• 2021

To improve safety analysis technology for a nuclear reactor containment considering an interaction between a reactor coolant system (RCS) and containment, this study aims at an experimental investigation on the integrated simulation of the RCS and containment, with an integral effect test facility, ATLAS-CUBE. For a realistic simulation of a pressure and temperature (P/T) transient, the containment simulation vessel was designed to preserve a volumetric scale equivalently to the RCS volume scale of ATLAS. Three test cases for a steam line break (SLB) transient were conducted with variation of the initial condition of the passive heat sink or the steam flow direction. The test results indicated a stratified behavior of the steam-gas mixture in the containment following a high-temperature steam injection in prior to the spray injection. The test case with a reduced heat transfer on the passive heat sink showed a faster increase of the P/T inside the containment. The effect of the steam flow direction was also investigated with respect to a multi-dimensional distribution of the local heat transfer on the passive heat sink. The integral effect test data obtained in this study will contribute to validating the evaluation methodology for mass and energy (M/E) and P/T transient of the containment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.331-341
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• 2007

Pre-loads could be imposed on the braced wall to prevent the horizontal displacements during the ground excavation adjacent to the existing tunnel. For this purpose, new pre-loading system through which large pre-loads could be applied to the braced wall was used in the model tests. Large scale model tests were performed in the real scale test pit which was 2.0 m in width and 6.0 m in hight and 4.0 m in length. Test ground was constructed by sand. Model tunnel in 1.2 m diameter was constructed before test ground excavation. Test ground was excavated adjacent to existing tunnel and was braced. To investigate the effect of pre-loading, tests without pre-load were also performed. During the ground excavation were the behavior of braced wall, test tunnel, and ground measured. Model tests were also numerically analysed and their results were compared to that of the real scale tests. As a result, it was found that the stability of the existing tunnel was greatly enhanced when the horizontal displacements of braced wall was reduced by applying pre-load larger than the design load.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.968-976
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• 2019

This paper presents a number of verification case studies for a recently developed sensitivity/uncertainty code package. The code package, ROMUSE (Reduced Order Modeling based Uncertainty/Sensitivity Estimator) is an effort to provide an analysis tool to be used in conjunction with reactor core simulators, in particular the Virtual Environment for Reactor Applications (VERA) core simulator. ROMUSE has been written in C++ and is currently capable of performing various types of parameter perturbations and associated sensitivity analysis, uncertainty quantification, surrogate model construction and subspace analysis. The current version 2.0 has the capability to interface with the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) code, which gives ROMUSE access to the various algorithms implemented within DAKOTA, most importantly model calibration. The verification study is performed via two basic problems and two reactor physics models. The first problem is used to verify the ROMUSE single physics gradient-based range finding algorithm capability using an abstract quadratic model. The second problem is the Brusselator problem, which is a coupled problem representative of multi-physics problems. This problem is used to test the capability of constructing surrogates via ROMUSE-DAKOTA. Finally, light water reactor pin cell and sodium-cooled fast reactor fuel assembly problems are simulated via SCALE 6.1 to test ROMUSE capability for uncertainty quantification and sensitivity analysis purposes.