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대학생 학업성취도와 대학입학전형 요소의 관계에 대한 메타분석
이명훈(Lee, Myeonghoon) 학습자중심교과교육학회 2017 학습자중심교과교육연구 Vol.17 No.24
본 연구에서는 타당도 높은 대학입학전형 제도를 마련하기 위한 시사점을 제공하고자 대학생 학업성취도에 영향을 미치는 대학입학전형 요소들의 효과를 수합하여 그 크기를 계량적 연구통합 방법인 메타분석(meta analysis) 통해 비교하였다. 그 후, 전통적 조절효과 검정 방식을 보완한 유사분산분석(analog to ANOVA)과 메타회귀분석(meta regression)을 활용하여 효과크기에 영향을 미칠 수 있는 조절변인들을 탐색하였다. 메타분석 결과, 내신이 대학생 학업성취도를 가장 잘 예측하는 것으로 나타났다. 수능은 대학입학전형 요소 중 가장 낮은 효과크기를 보였고 시간이 흐를수록 예측력이 감소하기도 하였다. 이는 수능이 예측타당도의 관점에서 타당하지 못한 선발도구임을 의미하며, 수능 위주의 전형방식이 개선되어야 한다는 것을 시사한다. 한편, 대학입학전형 요소 중 효과크기가 가장 높은 내신조차도 0.2 미만의 중간 이하의 효과크기를 나타냈다는 점에서 향후 높은 예측타당도를 갖춘 새로운 평가 요소들의 탐색이 필요함을 제언하였다. Current elements of the college admission process must accurately predict the potential scholastic aptitude of the students colleges seek to obtain. However, whether current admission factors demonstrate a high predictive validity remains a controversial question, since preceding research proposes mixed results on the influence and the predictive power of these factors. This study has, therefore, attempted to provide suggestions in creating a highly valid college admission process system in the future, by conducting an integrated analysis on the effectiveness of admission factors that influence college student academic achievement, and comparing the effect size of current admission factors to draw a general conclusion. As a result, school records were the most predictive admission factors. The CSAT scores showed the lowest effect size among college admission factors, and the predictive power decreased with time. This means that the CSAT is not a valid selection tool in terms of predictive validity, suggesting that the SAT method should be improved.
신경망 분석을 활용한 학교폭력의 예측요인 분석 및 해결방안 모색
이명훈(Lee, Myeonghoon) 학습자중심교과교육학회 2017 학습자중심교과교육연구 Vol.17 No.22
본 연구는 한국아동 청소년패널조사 제 6차년도(2015년) 조사 자료의 초·중·고등학생 총 6,184명의 표본을 대상으로 학교폭력 가해행동의 예측요인을 분석하기 위해 로지스틱 회귀모형과 신경망 모형을 추정한 후, 이 중 예측력과 신뢰성이 높은 분석 모형을 도출하는 탐색적 연구로 진행되었다. 가장 적합한 추정 모형으로 판별된 신경망 모형을 의사결정나무 모형으로 변환하여 해석한 결과, ‘학교폭력 가해경험이 있는 친구의 수’가 학교폭력 가해행동에 가장 주요한 예측요인으로 나타났다. 학교 폭력 가해 친구가 많고 공격성이 높은 남학생(74.19%), 그리고 학교폭력 가해경험이 있는 친구가 많지만 공격성이 낮으며 공동체 의식은 양호하나 교사와의 유대관계가 부족한 학생(80.00%)들은 학교폭력 가해확률이 높은 집단군으로 파악되었다. 연구를 통해 도출된 주요 예측요인들이 학교폭력 가해행동과 어떻게 관련되는지 논의한 결 과, 학교폭력을 거시적 사회문제로 인식하는 태도 및 학교와 사회 내 폭력적 문화개선이 필요함을 해결방안으로 제언하였다. This study was conducted on a sample of 6,184 elementary, middle, and high school students in the 6th year of KCYPS survey. The purpose of this study is to investigate the predictive factors of school violence behavior by using logistic regression model andnneural network model. As a result of the neural network based decision tress model identified as the most suitable estimation model, the number of friends who were school violence offenders was the most important predictor of school violence behavior. Based on the research results of relations between the main predictors and school violence behavior, this research suggests educational ways to solve the problem of school violence: It is necessary to view school violence as a macro problem, not a micro problem and efforts should be made to eliminate violent schools and social cultures.
차량 내부 조향장치 파손방지를 위한 아우터 타이로드의 최적 휨 설계
은효준(Hyojun Eun),신용상(Yongsang Shin),안명훈(Myeonghoon Ahn),정연웅(Yeonwoong Jung),김민준(Minjoon Kim),이문규(Moonkyu Lee),이희갑(Hee-Gab Lee),추용주(YoungJu Chu),이승엽(Seung-Yop Lee) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
In the automobile steering system, Tie-rod acts as a sacrificial part to protect the inner steering gear such as rack and pinion. Therefore, the allowable maximum buckling load is crucial design constraint as well as minimum buckling load. The previous model was recognized to be overdesigned so that it should be remodeled to reduce critical buckling load. In this paper, we showed design method of bent outer Tie-rod giving initial imperfection with eigen buckling mode. However, the bent design brings about mass gain although it makes substantial decrease of critical buckling load. So we set the multi-objective optimizing problem to minimize the value of critical buckling load and mass gain with two kinds of structure design variables – scale factor & bent length. As a result, we obtained the optimum parameters that reduced critical buckling load by 64.96%, and 9.05% mass gain.
P&ID의 파이프라인 인식 향상을 위한 라인 검출 개선에 관한 연구
오상진,채명훈,이현,이영환,정은경,이현식,Oh, Sangjin,Chae, Myeonghoon,Lee, Hyun,Lee, Younghwan,Jeong, Eunkyung,Lee, Hyunsik 한국플랜트학회 2020 플랜트 저널 Vol.16 No.4
For several decades, productivity in construction industry has been regressed and it is inevitable to improve productivity for major EPC players. One of challenges to achieve this goal is automatically extracting information from imaged drawings. Although computer vision technique has been advanced rapidly, it is still a problem to detect pipe lines in a drawing. Earlier works for line detection have problems that detected line elements be broken into small pieces and accuracy of detection is not enough for engineers. Thus, we adopted Contour and Hough Transform algorithm and reinforced these to improve detection results. First, Contour algorithm is used with Ramer Douglas Peucker algorithm(RDP). Weakness of contour algorithm is that some blank spaces are occasionally found in the middle of lines and RDP covers them around 17%. Second, HEC Hough Transform algorithm, we propose on this paper, is improved version of Hough Transform. It adopted iteration of Hough Transform and merged detected lines by conventional Hough Transform based on Euclidean Distance. As a result, performance of Our proposed method improved by 30% than previous.
이일석(Ilseok Lee),고명훈(Myeonghoon Ko),남연경(YunKyung Nam),진상은(Sangeun Jin) 대한인간공학회 2019 대한인간공학회 학술대회논문집 Vol.2019 No.10
Objective: This study aimed to develop ergonomic guidelines for the standing desk with a focus on the use of armrest that may significantly modify the shoulder, arm, wrist and neck postures. Background: Applicable ergonomic guidelines exist for the sitting office workstation, but previous studies revealed that the guideline is not adaptable in the standing workstation, in that the workstation changes shoulder, elbow and wrist postures. Method: Fourteen healthy male participants were asked to use two standing desk shapes (plane and concave (assuming armrest) boards), two monitor heights (eyeline and -10cm from eyeline), and three desk heights (-5, 0, +5 from elbow height) for three minutes. Also, two sitting postures with or without a backrest were recorded. During the experimental trials, the kinematic and muscle recruitment patterns in neck, lumbar, shoulder and wrist were measured by the motion capture system and EMG, and the desk location, monitor height and angle were recorded. Results: In general, use of the standing desk showed significantly better lower back, shoulder and head postures as comparted to the sitting workstation, but the wrist extension angle was significantly increased in the standing posture, especially in the desk height of -5 and 0 cm. In contrast, the wrist extension angle showed a significant decrease (14.3%, about 4°) under the +5 cm height condition, suggesting a positive effect of the armrest, but at the cost of ulnar deviation (10.4%, about 2°). The following EMG analysis support the result extensor carpi radialis (ECR) and paraspinals at L4. Under the +5 cm height condition, the positive effects of armrest resulted in 2% and 1% decrease in muscle activation level of extensor carpi radialis and paraspinals at L4, respectively. The benefit of the higher desk was also showed on rounded shoulder angle (about 2.3° decreased under the +5 cm height), but at the cost of shoulder abduction angle (about 12°). The two negative effects (ulnar deviation and shoulder abduction angle) can be solved. In shoulder abduction case, the armrest supports the load from the abduction, and wrist ulnar deviation can be solved by using the ergonomic keyboard which the center is bent. Conclusion: This study found that the standing desk had positive effects on wrist, shoulder and head posture same as the previous study. Furthermore, current study found that the standing desk with armrest (desk under the +5 cm height) effect showed more positive effects on various upper extremities. Application: Using a standing desk instead of sitting desk can be a good strategy. Especially, the use of standing desk under the +5 cm height condition will have a positive effect on the prevention of worker’s musculoskeletal disorders.