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유아교사의 놀이교수효능감과 놀이중심 교육과정 실행 실제의 관계에서 확산적사고와 몰입의 매개효과 분석
유지영 ( Yu Jiyoung ),박경희 ( Park Kyunghee ),김윤희 ( Kim Yunhee ) 한국유아교육학회 2022 유아교육연구 Vol.42 No.6
The purpose of this study was to examine the structural relationship in which early childhood teachers’ play-based teaching efficacy has direct and indirect effects on the play-based curriculum implementation practice, which were mediated by divergent thinking as well as flow. The subjects of the study were 214 early childhood teachers in Seoul and Gyeonggi-do, and other regions in South Korea. The collected data were analyzed using the structural equation modeling by SPSS and AMOS 21.0 program. The major findings are as follows. First, early childhood teachers’ personal efficacy measured by the play-based teaching efficacy had a direct effect on the play-based curriculum implementation practice and had an indirect effect on it via the divergent thinking as well as flow. Second, early childhood teachers’ outcome efficacy measured by the play-based teaching efficacy had a direct effect on the play-based curriculum implementation. There was a mediated path proceeding from outcome efficacy→ divergent thinking→ flow to play-based curriculum implementation. Based on these results, the necessity of developing and distributing various teacher training and education programs to enhance the play-based teaching efficacy and creativity of early childhood teachers was discussed.
자동차 차체용 AHSS 소재에 대한 AC 펄스 GMA 용접성 평가
소우주(Wooju So),유지영(Jiyoung Yu),김동철(Dong Cheol Kim),강문진(Moon Jin Kang),박영환(Young Whan Park),이세헌(Sehun Rhee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4
본 연구에서는 극성 가변 효과와 펄스 전류 특성을 이용한 AC 펄스 GMA 용접을 자동차 차체용 AHSS 소재의 용접 공정에 적용하였다 먼저 AC 펄스 GMA 용접에서 EN ratio 변화에 의한 아크 용융현상과 비드 형상의 변화에 대해 분석하였다. EN ratio가 증가함에 따라 아크 루트가 전극 와이어에 형성되는 시간이 증가하여 와이어 용융속도가 증가하고 모재쪽의 입열이 감소하는 것을 확인하였으며, EN ratio 변화에 따른 비드 형상 변화를 분석하였다. 또한 자동차 차체용 AHSS 소재에 대한 AC 펄스 GMA 용접의 갭 접합성 평가를 통해 생산 현장에서 겹치기 용접 이음부의 0~1㎜ 갭 발생에 대해 적정 용접조건을 제시하였다. Because of the recent increase in oil prices and people's growing interest in environmental issues through the world, automobile makers have conducted various studies on improving fuel efficiency through weight reduction in vehicles. One of the most widely known car weight-reduction methods is to use high strength steel. However, because of poor weldability and gap occurrence in assembly process caused by spring back, it is difficult to obtain good weld quality when working with the AHSS. In this paper, pulse GMA welding which uses changes in the polarity and the characteristics of pulse current, has been applied to the arc welding of AHSS for automobile body.
Mg-6.7 wt.% 알루미늄 합금의 GMA 및 GTA 용접 특성평가
강태훈(Taehoon Kang),유지영(Jiyoung Yu),김영민(Young-Min Kim),황인성(Insung Hwang),이승환(Seung Hwan Lee),김동윤(Dong-Yoon Kim) 대한용접·접합학회 2021 대한용접·접합학회지 Vol.39 No.5
본 연구에서는 마그네슘이 6.7 wt.% 함유된 알루미늄 합금 Al-6Mg에 대하여 기존 상용화된 알루미늄 Al5083-O과 GMAW, GTAW의 용접성 평가를 진행하였다. 1) GMAW 공정은 와이어 송급속도 3.0, 3.5 m/min에서 최적 용접 구간을 확인하였고, GTAW 공정의 경우 용접전류 70, 80 A에서 최적 용접 구간을 보였다. 2) 인장시험 결과 모든 공정 및 조건 용접부에서 파단이 발생했으며, Al-6Mg의 용접부 인장강도가 Al5083-O 대비 GMAW에서 최대 20 %, GTAW에서 최대 10 % 더 높은 값을 보였다. 3) 경도시험 결과 Al-6Mg의 모재 경도값이 Al5083-O 보다 약 33% 높았지만, 모든 공정, 조건 용접부에서의 경도분포는 유사했다. 용접부에서의 경도분포가 유사한 이유로는 Al5083-O에 함유 된 Mn과 Cr의 영향으로 판단된다. 4) 용접부 EBSD 분석결과 GMAW, GTAW 용접 모두 Al-6Mg의 용접부 평균 결정립 크기가 약 15% 더 작게 나타났으며, 용접부 EDS 분석결과 잔여 마그네슘 함량이 GMAW의 경우 37%, GTAW의 경우 30% 높은 값을 보였다. 본 연구 결과 Al-6Mg의 용접부 인장강도는 Al5083-O 보다 용접부의 잔여 마그네슘 함량이 높았고, 더 작은 평균결정립 크기를 갖는다. 이로 인해 Al-6Mg의 용접부 인장강도는 Al5083-O보다 향상되었다. 하지만 GMAW, GTAW 두 공정 모두 용접부에서 Al-6Mg와 Al5083-O의 경도가 비슷한 분포를 보였으며 이러한 원인을 규명하기 위해 연구를 진행 중이다. In this study, the arc weldability of an aluminum alloy was investigated based on its Mg content. The base materials used in the experiments were aluminum with a Mg content of 6.7 wt.% (referred as Al-6Mg) and commercial Al5083-O. The weldability of two types of fusion welding methods was evaluated: gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW). The tensile strength, hardness, alloy composition, and microstructure properties of the welds of two types of the aluminum alloys were compared. The tensile strength values of the GMAW and GTAW welds of Al-6Mg were 20% and 10% higher than those of Al5083-O, respectively. The weld hardness of the GMAW and GTAW welds of both aluminum alloys were similar. Al-6Mg by GMAW and GTAW were smaller than those of Al5083-O. Based on the results of analysis of the welds, the residual magnesium content was as high as 37% by GMAW and 30% by GTAW.
맞대기 V형 그루브의 GMA 초층용접에서 합성곱 신경망을 이용한 이면비드 발생 예측 모델 개발
이형원(Hyung Won Lee),유지영(Jiyoung Yu),김광국(Gwang-Gook Kim),김영민(Young-Min Kim),황인성(Insung Hwang),이승환(Seung Hwan Lee),김동윤(Dong-Yoon Kim) 대한용접·접합학회 2021 대한용접·접합학회지 Vol.39 No.5
Gas metal arc (GMA) welding is widely used in the machinery industry. The quality of a welded joint is affected by the penetration of root pass welding in the V-groove joint. Automation using GMA welding is continuously required, and root pass welding automation is required to automate the entire welding process. In particular, the development of a prediction model that can ensure full penetration back-bead is required for the automation of root pass welding. In this study, a convolutional neural network (CNN) model was applied to predict the occurrence of back-bead in V-groove butt joint GMA root pass welding. The bead profile was measured using a laser vision sensor system and it was used as the input data for the prediction model, and the bead occurrence was used as the output data for the model. A total of 12,873 bead profiles were extracted and pre-processed through cutting, resizing, and thresholding. The CNN model consists of nine layers, and performs three convolution and two pooling operations. The accuracy of the prediction model was 99.5%, and through this study, it was demonstrated that the quality of root-pass welding can be controlled by using convolutional neural network and it can contribute to automation.
이소림,조성우,김동언,유지영,이은미,Lee, Solim,Cho, Sungwoo,Kim, Dongeon,Yu, Jiyoung,Lee, Eunmi 한국건설안전학회 2019 한국건설안전학회 논문집 Vol.2 No.2
본 연구는 건설관련 업무를 수행하는 종사자들을 대상으로 DfS제도에 대한 설문을 실시하고 그 결과를 분석하여 개선방향을 제시하는 것을 목적으로 한다. 설문결과는 제도에 대한 인지도 및 필요성에 대해서 약 82%, 93%의 긍정적인 결과가 나타남으로써 제도가 차츰 정착되고 있음을 알 수 있었다. 또한, 제도의 개선방향에 대해서 가장 높은 응답율을 나타낸 3가지는 첫째, DfS관련 수행인원의 전문성 향상, 둘째, DfS관련 주체들의 인식개선, 셋째, DfS관련 적정비용 반영이었다. 위 개선사항의 실현을 위한 방안으로는 담당자 전문성 향상을 위한 교육과정 마련, 인식개선을 위한 인센티브제 시행, 시공단계에서 활용가능한 보고서 작성을 위한 적정대가 지급기준 마련을 제안하였다. 아울러 설계단계부터 건설사고 위험요소를 선제적으로 관리하는 제도가 되기 위하여 한국시설안전공단의 적극적인 역할수행이 필요할 것이다. The purpose of this study is to conduct survey on the DfS system for employees who perform construction-related tasks, analyze the results, and present improvement directions. The results of the survey showed that the system was gradually being settled, with about 82% and 93% positive results on the recognition and necessity of the system. In addition, the three highest response rates for the improvement of the system were first, improving the expertise of DfS-related performance personnel, second, improving the awareness of DfS-related actors, and third, reflecting the appropriate costs associated with DfS. For the realization of the above improvements, it was proposed to prepare a curriculum for improving the professionalism of the staff, to implement an incentive system for improvement of perception, and to prepare appropriate payment criteria for preparing reports available during the construction phase. In addition, the Korea Infrastructure Safety and Technology Corporation will need to perform its active role in order to become a system for preemptive management of risk factors for construction accidents from the design stage.