• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6C
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• pp.313-319
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• 2009

In this study, field pull-out test and 3-D FEM analysis have been performed for examining and reflecting the behavior of steel pipe nailing installed foldable wedge. Field pull-out test was performed under various conditions. As a result, the steel pipe nailing installed foldable wedge has an effect of pull-out resistance increased about 30% in comparison with non-wedge type steel pipe nailing. Through back analysis in 3-D FEM for behavior of non-wedge type steel pipe nailing, friction characteristics between nail to soil was analyzed and obtained first consistent with field pull-out behavior. Then, the frictional characteristic was used for analyzing the behavior of the steel pipe nailing installed foldable wedge. The result was compared with the test results. Consequently, friction coefficient (${\mu}$) of about 1.2 between grout to soil leads to good agreement with analysis results and test results. And a limited pull-out resistance, $$T_L{\sim_=}32$$ tonf is similar to field pull-out test result which is improved about 33% in comparison with non-wedge type steel pipe nailing's $$T_L{\sim_=}24$$ tonf.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.13 no.2
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• pp.45-54
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• 2007

The purpose of this study was effect of hamstring length on one leg stance test(OLST) in 108 persons. (men 28, women 80). The active knee extension test(AKE) was applied 3 times on both leg and high score was selected. Then, one leg stance test(OLST) was applied 3 times on both leg and high score was selected. Also, persons divided two group that is normal hamstring length group and shortening group). The result were as follows : 1. The correlation analysis between Lt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.271$, $p_{Rt.}=0.051$). 2. The correlation analysis between Rt. hamstring length and one leg stance time was no significant relation($p_{Lt.}=0.837$, $p_{Rt.}=0.334$). 3. The independent T -test between Lt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in Lt. leg stance time was no significant difference(p=0.73), but in Rt. leg stance time was statistically significant difference(p=0.04). 4. The independent T-test between Rt. hamstring normal (knee extension > 150degrees) & shortening group (knee extension ${\leq}$ 150 degrees) in one leg stance time was no significant difference($p_{Lt.}=0.09$, $p_{Rt.}=0.16$).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.82-87
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• 2004

The general requirements to achieve the structural integrity of the airframe are described in the military specification, MIL-HDBK-1530. One of these requirements is the durability and damage tolerance of the airframe, which should be shown through the analysis and test based on the related specifications. This paper describes the full scale durability test load simulation to evaluate the structural safety and durability of the advanced trainer, T-50. The test load simulation was performed according to the procedure in the military specification and the KAF contract requirements. The durability test design technique which involve the floating test set-up, the optimal test load simulation method, and the 6-DOF test article balance method to secure the real flight conditions as many as possible. It was confirmed that this method will be available in a similar full-scale airframe structural test in future.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.153-153
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• 2012

기후변화는 강우량, 기온, 해수면온도 등 많은 수문기상학적 요소에 영향을 끼치고 있으며 이러한 영향에 대한 연구가 활발하게 진행되고 있다. 그 중에서도 수공구조물의 설계에 직접적으로 영향을 끼치는 강우특성에 대한 연구는 기후변화로 야기되는 강우의 비정상성(non-stationary)을 중심으로 이루어지고 있다. 현재 수문설계량은 강우량의 빈도해석을 통해 산정되는데, 이러한 빈도해석은 기본적으로 연최대강우자료의 정상성(stationary)과 독립성(independent)을 가정하고 이루어진다. 그러나 기후변화로 연최대강우자료에 경향성이나 변동성이 나타남에 따라 경향성과 변동성을 고려할 수 있는 빈도해석 기법의 개발에 대한 필요성이 증가하고, 실제로 2000년대에 들어서면서부터 우리나라뿐만 아니라 전 세계적으로 이루어지고 있다. 연최대강우자료의 정상성을 판단하기 위해 강우자료에 대한 경향성 분석을 수행하게 되는데, 경향성 분석을 위해 다양한 통계적 기법들이 적용되고 있다. 그러나 현재 경향성 분석방법의 적용에 대한 뚜렷한 기준이 없어 여러 가지의 경향성 분석 방법을 적용하여 다수의 분석방법별 결과를 종합하여 경향성 유무를 판단하고 있는 실정이며, 동일자료에 대해서도 연구에 따라 다른 결과가 나타나고 있다. 따라서 본 연구에서는 경향성 분석방법의 기각력을 비교검토하여 경향성 분석방법의 적용에 필요한 기준을 제시하고자 한다. 이를 위해 경향성 분석을 위해 널리 사용되고 있는 t-test, Mann-Kendall test, Hotelling-Pabst test를 비교하고자 한다. 여기에서 t-test는 매개변수를 사용하는 매개변수적 방법이고, Mann-Kendall test와 Hotelling-Pabst test는 비매개변수적 방법이다. 귀무가설의 경우 t-test는 경향성이 없다고 가정하고 있는데 반해, Mann-Kendall test와 Hotelling-Pabst test는 경향성이 있다고 가정하고 있다. 기각력 검토를 위해서는 Monte Carlo simulation을 이용하였다.

• Journal of Industrial Convergence
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• v.22 no.8
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• pp.73-83
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• 2024

The study attempted to examine the effects of hybrid simulation practice program on critical thinking disposition, self-efficacy, communication competency, and clinical competency of nursing students. The study was one group pre-test and post-test design. Data were collected between April 24 to May 5, 2023 from 35 nursing students. The collected data was analyzed using the SPSS 25.0 program, frequency analysis, mean, standard deviation, and paired t-test. Research results showed that nursing students' critical thinking disposition(t=7.01, p<.001), self-efficacy(t=2.17, p=.037), communication competency(t=2.70, p=.011), and clinical competency(t=6.60, p<.001) were improved after the simulation program. The hybrid simulation practice program is significant in that it applies various learning tools, including high-fidelity-low-fidelity-role play to strengthen the connection between nursing students' theory and practice.

• Archives of Metallurgy and Materials
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• v.64 no.2
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• pp.617-622
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• 2019

This study investigated the effect of T6 heat treatment on the microstructure and scratch wear behavior of hypoeutectic Al-12wt.%Si alloy manufactured by extrusion. Microstructural observation identified spherical eutectic Si phases before and after the heat treatment of alloys (F, T6). Phase analysis confirmed Al matrix and Si phase as well as Al₂Cu and Al₃Ni, Mg₂Si in both alloys. In particular, Al₂Cu was finer and more evenly distributed in T6 alloy. This resulted in Vickers hardness of T6 alloy that was 2.3 times greater compared to F alloy. The scratch wear test was conducted using constant load scratch test (CLST) mode and multi-pass scratch test (MPST) mode. The scratch coefficient and worn out volume obtained by such were used to evaluate wear properties before and after heat treatment. In the case of T6 alloy, its scratch coefficient was lower than F alloy in all load ranges. After 15 repeated tests to measure worn out volume, F alloy and T6 alloy measured 1.2×10^-1 mm³ and 7.8×10^-2 mm³, respectively. In other words, the wear resistance of T6 alloy were confirmed to be better than those of F alloy. In addition, this study attempted to identify the microstructural factors that contribute to the better scratch wear resistance of T6 alloy and wear mechanism from surface and cross-section observations after the wear tests.

• Journal of the Korean Society of Costume
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• v.28
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• pp.137-150
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• 1996

The objectives of this study were to classify daily clothing selection motives and to group men into life style types and to examine the differences in daily clothing selection motives according to the life style types. Questionnaire comprised of three sections: 36 Likert type items of life style measure; 29 Likert type items of daily clothing selection motives measure: and 4 demographic variables. Samples were 267 salary men in gheir 20's to 30's in Seoul Korea. The data were analyzed using factor analy-sis cluster analysis one-way ANOVA Dun-can's multiple range test and t-test. 1. Five factors of life style were derived by factor analysis ; F. 1 'appearance oriented' f. 2. 'positive activity' F. 3 'economy oriented': F.4 'active-leisure';F. 5 'contemporary' Four types of life style of men were defined by cluster analysis of the five factors: T. 1'posi-tive activity'; T. 2.'economy interest'; T. 3'contemporary' : T 2'economy interest' T.3'contemporary' ; T. 4 'appearance interest' 2. Four factors of daily clothing selection motives were derived by factor analysis: F.1 'clothing harmony'; F.2 'clothing utility'; F.3 'psychological influence'; F.4 'exogenous situ-ation adaptation 3. There were significant differences in daily clothing selection motives according to the life style types. The types of positive activity economy interest and contemporary had 'clothing utility' motive more than appearance interest type. Economy interest type had 'hpsychological influence' motive more than other three types. Economy interest type and appearance interest type had 'exogenous situ-ation adaptation' motive more than other two types 4. 20's and unmarried men had'psychological influence' motive more than 30's and married. Upper class had 'clothing harmony' and 'ex-ogeneous situation adaptation' motives more than middle and low. Men with less education had ' clothing utility' and 'exogenous situation adaptation' motives more than did more edu-cation.

• Journal of The Korean Institute of Defense Technology
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• v.5 no.2
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• pp.1-9
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• 2023

The purpose of this study is to derive the need to improve the test and evaluation(T&E) performance system of the weapon systems to which advanced science and technology is applied, evaluate priorities, and present development plans. T&E of Al-based weapon systems through a literature research and case analysis on changes in the T&E environment for weapon system, 11 detailed evaluation items were derived from the in terms of the T&E system, structure, and technology. Al-based weapon system test evaluation should be performed in parallel with data-based performance evaluation and actual T&E, and performance measurement using a separate T&E data set is required for AI models performance evaluation. As a result of analyzing the importance of T&E through AHP analysis, the order of T&E system-technology-structure was evaluated, and the priority of detailed evaluation items was evaluated in the order of T&E result judgment-T&E organization and expert training-scientific T&E. For evaluation items with high priority, measures to improve the T&E performance system were presented.

• 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.

• Steel and Composite Structures
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• v.22 no.2
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• pp.217-234
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• 2016

In order to investigate mechanical properties and load-bearing capacity of T-shaped Concrete-Filled Square Steel Tubular (TCFST) composite columns under eccentric axial load, three T-shaped composite columns were tested under eccentric compression. Experimental results show that failure mode of the columns under eccentric compression was bending buckling of the whole specimen, and mono column performs flexural buckling. Specimens behaved good ductility and load-bearing capacity. Nonlinear finite element analysis was also employed in this investigation. The failure mode, the load-displacement curve and the ultimate bearing capacity of the finite element analysis are in good agreement with the experimental ones. Based on eccentric compression test and parametric finite element analysis, the calculation formula for the equivalent slenderness ratio was proposed and the bearing capacity of TCFST composite columns under eccentric compression was calculated. Results of theoretical calculation, parametric finite element analysis and eccentric compression experiment accord well with each other, which indicates that the theoretical calculation method of the bearing capacity is advisable.