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일차방정식에 대한 학습부진아를 위한 CAS 계산기 활용 수업의 효과
이원효,백선수,김원경 한국교원대학교 교육연구원 2009 敎員敎育 Vol.25 No.2
The purpose of this study is to analyze effectiveness of CAS calculator lesson for slow learners in linear equation. For this study, subjects of 4 students(2 boys and 2 girls) at H middle school who are going through difficulties in learning of linear equation were selected. Seven hours of CAS calculator lesson were carried out to investigate features of the learning process and mathematical achievement. The research findings are as follows. First, students understood clearly the meaning of the linear equation. Second, students searched various problem solving methods. Third, students writing ability of mathematical symbol and terminology were improved. Fourth, students had confidence on solving the linear equation. Fifth, students' mathematical achievement were improved. 중학교 학생들 중에는 일차방정식, 특히 계수가 분수 또는 소수인 일차 방정식을 푸는 과정에서 학습 부진을 보이는 학생이 많이 있다. 학습 부진아에게 수학적 개념을 이해시키고 성취도를 높이기 위해서는 교수-학습 방법의 개선이 필요하며 그 대안 중의 하나가 CAS 계산기이다. 본 연구에서는 일차방정식에서 학습 부진을 보이는 중학생을 대상으로 CAS 계산기를 활용한 일차방정식 수업을 통해 학생들의 학습 과정의 특징과 성취도 효과를 분석함으로써 향후 일차방정식의 수업 현장에서 학습부진아에 대한 적절하고 효과적인 교수-학습 프로그램을 제시하고자 하였다.
윤곽선 정보와 watershed segmentation을 이용한 영역 추출
이원효,설경호,염동훈,고기영,김두영 동아대학교 정보기술연구소 2003 情報技術硏究所論文誌 Vol.11 No.1
This paper proposed a extracting method of the region for image using segmentation and edge information. First proposed algorithm extract information using canny edge detector and the image was divided by watershed segmentation. And it extract the image with edge information by merging region. Finally we compare the proposed method with levelset method. In the result proposed method not only extract the image with accurate region but also reduce operation time.
수치해석을 이용한 말뚝이 결합된 블록식방파제의 수평저항력에 관한 연구
이원효,권순구,김태형 한국해안,해양공학회 2022 한국해안해양공학회 논문집 Vol.34 No.4
Three-dimensional FEM numerical analysis was performed to understand the behaviors of blocks and piles according to the horizontal load for the block breakwater combined with piles. The Modified Mohr-Coulomb model, the improved version of the Mohr-Coulomb model, was applied for the ground modeling. The cases when the pile is embedded only into the block, embedded to the riprap layer (H = 4.29 cm), and embedded to the ground down to 2H, 3H, and 4H were examined. The results of the laboratory model experiment and the numerical analysis showed similar horizontal resistance force-displacement behaviors. The pile showed rotational behavior up to the embedment depth of 1H~2H and bending behavior in the case of 3H~4H depth embedment. When the embedment depth of the pile is 3H or more, the pile shows a bending behavior, so it can be considered that the pile contributes significantly to the horizontal resistance of the block breakwater. The results of this study will be used for various numerical analyses for real-size structure design. 본 연구는 말뚝이 결합된 블록식방파제에 대하여 수평하중 재하에 따른 블록과 말뚝의 거동을 파악하기 위하여 FEM 3차원 수치해석을 실시하였다. 지반구성모델은 Mohr-Coulomb 모델을 향상시킨 Modified Mohr Coulomb 모델을 적용하였다. 말뚝이 블록에만 관입된 경우, 사석층(H = 4.29 cm)까지 근입된 경우, 원지반속에 근입된 2H, 3H, 4H의 경우에 검토하였다. 실내모형실험 결과와 수치해석를 비교한 결과, 수평저항력-변위가 서로 유사한 거동을보이는 것으로 나타났다. 말뚝의 근입깊이가 1 H~ 2H까지는 말뚝이 회전거동을 보이고, 3H~4H의 경우에는 휨거동양상을 보이는 것으로 해석되었다. 말뚝의 근입깊이가 3H 이상인 경우에는 말뚝이 휨거동을 보이므로 말뚝이 블록식방파제의 수평저항력에 크게 기여한다고 볼 수 있다. 본 연구 결과는 실제 크기 구조물 설계를 위한 다양한 수치해석 시 자료로 활용이 있을 것이다.
중증외상환자의 전산화단층촬영 및 중재술에 의한 방사선 유효선량 및 생애 귀속위험도
이원효,공태영,김승환,유제성,박유석,이재길,정성필 대한응급의학회 2013 대한응급의학회 학술대회초록집 Vol.2013 No.2
Purpose: To calculate and analyze the effective radiation doses from computed tomography (CT) and radiologic intervention in patients with trauma critical pathway (CP) activation in emergency department (ED), and further, to estimate the lifetime attributable risk (LAR) of incidence and mortality of cancers by the radiation dose. Methods: Through the retrospective electrical chart review of 104 injured patients who trauma critical pathway were activated from November 2012 to March 2013, we calculated radiologic effective doses, which are to multiply Dose-Linear Product of the scan by conversion coefficient. After determination of the image results whether negative or positive, we calculated the effective dose for each group. With these results, we estimated the LAR of incidence and mortality of cancers using Biologic Effects of Ionizing Radiation (BEIR)- VII report table. Results: Total 76 patients were enrolled. The mean age was 49.0±8.5years. The mean injury severity score (ISS) was 12.7±8.4. The cumulative effective dose (CED) for individual patient varied from 2.8 mSv to 238.8mSv, and the mean was 47.6±39.9 mSv. The CED in patients whose ISS≥16 (63.2±26.6 mSv) was higher than that of patients whose ISS<16 (33.5±23.1 mSv) (p<0.001). The CED in patients who were treated with operation or intervention (69.0±45.2 mSv) was higher than that of patients who were treated conservatively (33.6±22.4 mSv) (p<0.001). The LARs of cancer incidence and mortality were 328.5±308.6 and 189.0±159.3 per 100,000 people, respectively. Conclusion: The CED and LAR for trauma CP-activated patients in the ED were significant and we might try to decrease the effective dose exposed to severely injured patients.