http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
차진현,정상준,최관호,Cha, Jinhyun,Chung, Sangjun,Choi, Kwanho 항공우주시스템공학회 2015 항공우주시스템공학회지 Vol.9 No.3
In this study, a transient structural load analysis system was constructed to calculate the applied load on the suspension equipment corresponding to the aircraft flight conditions based on military specifications. Aircraft flight data (altitude, velocity, acceleration, angle of attack and etc. at aircraft center of gravity) were used as input parameters and the calculated load of the suspension equipment at wings on the left and right side was printed out for the structural load analysis. As a calculation procedure, first of all, load analysis was carried out at the center of gravity of the external store, Secondly, a trial reaction force analysis was conducted on hook and swaybrace of suspension equipment. All procedure of calculations was programed to analyze the structural load automatically. To verify the numerical results, structural load analysis using the experimental flight data was performed.
등가강성모델 기반의 양방향 유체구조 연성해석을 적용한 NREL Phase VI 풍력 로터 시스템의 공력특성 평가
차진현(Jin Hyun Cha),송우진(Woo Jin Song),강범수(Beom Soo Kang),김정(Jeong Kim) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.7
본 논문은 상용 유한요소코드인 ANSYS Workbench 12.1과 CFX 12.1을 이용하여 NREL Phase VI Rotor에 대한 공력특성을 입구풍속 7m/s 경우에 대해 연구하였다. 공탄성 효과를 고려하기 위해 약결합 양방향 유체구조 연성기법을 사용하여 타워구조를 제외한 로터파트에 대해서 해석이 수행되었다. 블레이드 끝단의 초기 피치각은 3°로 설정하였고, 구조해석모델은 등가강성기법을 적용하였다. 신뢰성 있는 수렴판정 결과의 확보를 위해 블레이드 루터부의 굽힘모멘트를 실시간으로 모니터링 하였다. 해석의 신뢰성을 검증하기 위하여 해석결과를 NREL/NASA Ames 풍동 실험결과와 비교 분석하였다. In this study, the evaluation of the aerodynamic characteristics of the NREL Phase VI Rotor System has been performed, for the 7 m/s upwind case using commercial FEA and CFD tools which are ANSYS Mechanical 12.1 and CFX 12.1. The initial operating conditions of the rotor blade include a 3° tip pitch angle. A numerical simulation was carried out on only the rotor parts, excluding the tower structure based on the equivalent stiffness model, to consider the aeroelastic effect for the numerical simulation using the loosely coupled 2-way fluid-structure interaction method. The blade root bending moment was monitored in real time to obtain reasonable results. To verify the analysis results, the numerical simulation results were compared with the measurements in the form of the root bending moment and the pressure distributions of the NREL/NASA Ames wind tunnel test.
의사결정나무분석 방법을 이용한 학업중단 변별 요인 탐색
양수경,차성현,남진현 한국교육개발원 2011 한국교육 Vol.38 No.4
본 연구는 중.고등학교 단계에서 학업을 중단한 학생들과 현재 재학 중인 학생들로부터 수집된 자료를 활용하여 의사결정나무분석과 이항 로지스틱 분석을 이용해 학업중단 가능성이 높은 학생들을 변별하는 요인을 탐색하고, 그 요인들이 학업중단에 미치는 영향력을 파악하고자 하였다. 이를 위해 한국교육개발원이 2010년도에 수행한 선행연구의 설문조사 자료를 사용하였다. 분석결과, 중학생의 학업중단에 가장 큰 영향을 미치는 요인은 학생의 무단결석 경험이었으며, 무단조퇴 및 가출 경험, 성별, 친부모와의 동거여부, 부모의 폭력성, 친구의 무단결석 경험, 학업을 중단한 친구여부 등도 중학생의 학업중단에 영향을 미치는 것으로 나타났다. 고등학생의 경우도 학생의 무단결석 경험이 학업중단에 가장 큰 영향을 미치는 요인이었으며, 수업 중 무단이탈, 무단조퇴 및 가출 경험, 부모의 폭력, 부모의 학업에 대한 억압, 부모와의 대화 정도, 부모의 교육지원, 친부모와의 동거여부, 학교소재지, 학교의 생활지도 엄격성 등이 학업중단에 영향을 미치는 것으로 나타났다. 이러한 결과를 토대로 학업중단 학생을 줄이기 위한 방안으로 전문상담교사의 확대 배치, 학부모 교육 강화, 가정‑학교간 실질적 의사소통 채널 마련 등을 제안하였다. The purpose of this study is to identify discriminant factors common to students at risk of dropping out and assess the factors' respective influence on the decision to drop out, utilizing a decision tree analysis and binomial logistic regression analysis on data collected from students currently enrolled and students who dropped out at the secondary education level. To achieve this end, this study used survey data collected for a prior study by KEDI in 2010. The analysis revealed that the risk factor most influential in a middle school student's decision to drop out was the student's experience with unexcused absences from school, and other risk factors included the student's experience with leaving school early during class hours without an excuse, experience with running away from home, the student's gender, whether the student lives with his or her biological parents, experience with parental violence, friends' experience with unexcused absences, and whether the student had dropout friends. For high school students, the student's experience with unexcused absences was the most influential risk factor in making a decision to drop out, and other factors included the student's experience with leaving class without an excuse, experience with leaving school early during class hours without an excuse, experience with running away from home, experience with parental violence, experience with parental pressure to achieve higher academic results, how much the student talks with his or her parents, parental support in education, whether the student lives with his or her biological parent, the school location, and how strict the school is in student guidance. Based on the results, to reduce the number of dropout students, this study suggested placing more professional counselors, reinforcing parental education, and providing a substantial communication channel between home and school.