• Title, Summary, Keyword: 효과크기

Search Result 5,159, Processing Time 0.051 seconds

A Meta-Analysis on the Effects of STEAM Education as an Education Policy of Korean Governments (융합인재교육의 정책적 목표를 중심으로 한 STEAM 교육의 효과성에 관한 메타분석)

  • Kang, Jiyeon;Jin, Sukun
    • Journal of the Korea Convergence Society
    • /
    • v.10 no.12
    • /
    • pp.205-213
    • /
    • 2019
  • Since 2011, when the Korean government initiated STEAM education in schools, many STEAM programs have been developed and many researches on STEAM education have been published in Korea. This meta-analysis examined the effectiveness of STEAM education by calculating effect sizes using statistics from 177 studies that reported their efforts in examining the effectiveness of STEAM programs. The findings of this study are the followings: 1)the total mean effect size of STEAM education is above medium level(effect size=.69). 2)Mean effect sizes of all four effect factors are above medium level, .58-.74. Mean effect sizes are .65 for STEAM interests, .74 for STEAM capacity, .63 for STEAM academic achievement, and .58 for STEAM careers. 3)The mean effect size of STEAM education in middle schools is significantly higher than in other school levels. This result suggests that STEAM education is more effective in middle schools.

Size effect on tensile strength of filament wound CFRP composites (필라멘트 와인딩 탄소섬유 복합재의 인장강도 크기 효과)

  • Hwang, T.K.;Doh, Y.D.;Kim, H.G.
    • Composites Research
    • /
    • v.24 no.5
    • /
    • pp.1-8
    • /
    • 2011
  • This paper presents the results of theoretical analysis and experimental test to show the size effect on the fiber strength of filament would pressure vessel. First, a series of fully scaled hoop ring tests with filament would carbon-epoxy were conducted, which exhibited a remarkable size effect on the fiber strength. Next, the failure analyses using WWLM(Weibull Weakest Link Model) and the SMFM(Sequential Multi-step Failure Model) were performed and compared to the hoop ring test data, as well as to unidirectional specimens test data from the literature. It was found that the analysis results significantly underestimated the fiber strengths compared to the test data. In this study, a modified SMFM was proposed through the modification of the length size effect. The fiber strengths from modified SMFM analysis showed good agreement with the test data.

Multiscale Analysis of the Thermoelastic Properties of Nanocomposites Considering Particle Size Effect (입자의 크기효과를 고려한 나노복합재료의 열탄성 물성의 멀티스케일 해석)

  • Choi, Joon-Myung;Yu, Su-Young;Yang, Seung-Hwa;Cho, Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • /
    • pp.119-122
    • /
    • 2011
  • 분자동역학 전산모사를 통하여 에폭시에 다양한 반경의 구형 실리콘 카바이드를 삽입한 나노복합재를 모델링하고, 이들의 기계적 물성과 열적 물성 해석을 다양한 온도조건 하에서 수행하였다. 전산모사 결과 동일한 체적분율 하에서 나노복합재는 입자의 크기가 작아질수록 탄성계수와 전단계수가 상승하는 동시에 선팽창계수는 감소하는 입자의 크기효과를 보였다. 또한 온도 상승에 따른 기계적 물성의 하락이 잘 관찰되었다. 본 연구에서는 이러한 분자동역학 해석 결과를 바탕으로 다양한 온도조건 하에서의 입자의 크기효과를 고려한 멀티스케일 3상 모델을 제시하였다. 유리상 조건 범위에서 온도 변화에 따른 나노복합재 계면의 열응력텐서와 열변형률텐서의 정보를 통해 복합재 내에서 계면이 차지하는 부피비를 온도에 대한 함수로 고려하고, 이를 멀티스케일 모델에 반영함으로써 다양한 온도조건에 대한 나노복합재 열탄성 물성의 예측해를 제시하였다. 본 연구에서 제시한 모델에서 계산된 3상 복합재의 물성은 분자동역학 전산모사의 결과에서 나타나는 나노입자의 크기효과를 잘 반영하였다.

  • PDF

A Statistical Approach for the Size Effect on the Strength of CFRP (탄소섬유 복합재의 강도 크기효과에 관한 통계적 접근)

  • Hwang, Tae-Kyeong;Kim, Hyung-Kun;Kim, Seong-Eun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • /
    • pp.472-476
    • /
    • 2011
  • This paper presents the results of theoretical analysis and experimental test to verify the size effect on the fiber strength of filament wound pressure vessel. As a test method, a series of fully scaled hoop ring tests with filament wound carbon fiber-epoxy has been conducted. Test results showed remarkable size effect on fiber strength. And, as an analytical method, the WWLM(Weibull weakest link model) and SMFM(sequential multi-step failure model) were considered and compared to hoop ring test data. The analysis results showed significantly lower fiber strength value than that of test data. Through the modification of length size effect, modified SMFM is suggested. The fiber strengths from modified SMFM showed good agreement with test data.

  • PDF

A Study on the Identification of Blur Extent from a Motion Blurred Image (모션 블러된 이미지로부터 블러의 크기를 추출하는 기법에 대한 연구)

  • Hwang, Joo-Yeon;Yang, Hong-Taek;Paik, Doo-Won
    • Journal of Korea Multimedia Society
    • /
    • v.10 no.10
    • /
    • pp.1251-1259
    • /
    • 2007
  • Motion blurs are caused by relative motion between the camera and the scene. The blurred image needs to be restored because undesired blur effect degrades the quality of the image. In this paper, we propose a new method for the identification of blur extent. Experiment shows that the proposed method identifies blur extent regardless of the size of the blur and the object in the original image.

  • PDF

Size Effect of Concrete Structures with Dissimilar Initial Cracks (비유사 균열이 있는 콘크리트 구조의 크기효과)

  • 김진근;어석홍;장정수;조성찬
    • Magazine of the Korea Concrete Institute
    • /
    • v.2 no.1
    • /
    • pp.91-100
    • /
    • 1990
  • In most of the structural members with initial cracks(or initial notches), the strength tends to decmase as the member size increases. This phenomenon is known as size effect. Among the structural materials of glass, metal or concrete, etc., concrete represents the size effect even without initial crack. According to the previous size effect law, the concrete mem¬ber of very large size can resist little stress. Actually, however, even the large size member can resist some stress if there is no initial crack made artificially, consequently showing a rather milder strength reduction compared to the severe strength reduction by tbe previously derived size effect law. In this study, the theoretical size effect law previously derived by Z.P. Bazant was discussed based on nonlinear fracture mechanics of concrete structures With dissimilar initial cracks, and the prediction models are proposed by regression analysis with the existing test data of more large size speciments for splitting tensile strength, shear strength and uniaxial compressive strength tests.

Numerical Analysis on the Size Effect of a Footing (기초의 크기효과에 관한 수치해석)

  • Lee, Seung-Hyun;Han, Jin-Tae
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.16 no.1
    • /
    • pp.778-784
    • /
    • 2015
  • Finite element analyses were conducted to investigate the size effect on the bearing capacity and settlement of shallow foundations, and the results were compared with those of theoretical equations. The calculated bearing capacity of the plate by numerical analysis and the theoretical equation was similar. Numerical analyses showed that the ultimate bearing capacity of strip footing on sand was affected by the size effect, whereas the ultimate bearing capacity of strip footing on clay was not affected by the size effect. Numerical analyses showed that the square footing was unaffected by the size effect regardless of the type of foundation soil. In contrast to theoretical equations, settlement of the footing was affected by the size effect and was proportional to the footing width.

Analysis on Effectiveness Research of Drama Education Program for Elementary School Students in Korea (한국의 초등학생을 위한 연극교육 프로그램의 효과성에 관한 연구)

  • Shin, Dong-In;Cho, Youn-Ho
    • The Journal of the Korea Contents Association
    • /
    • v.14 no.1
    • /
    • pp.528-536
    • /
    • 2014
  • The purpose of this study was to examine the effectiveness of drama education program for elementary school students by using method of meta-analysis. For the purpose of the study, master's theses, doctoral dissertations, and journal articles published in Korea up to July, 2013 were systematically reviewed. As a result, a total of 19 studies were eligible for the inclusion criteria. The mean effect sizes and test for homogeneity of effect size(Q-statistic) were analyzed by using Comprehensive Meta-Analysis software 2.0. The main findings of the study were as follows. First, the average effect sizes for drama education program were ES=1.103 of self-expression, ES=1.011 of self-esteem, ES= .858 of creativity and ES= .672 of sociality. Second, by analysing the moderate variables of the effect size for drama education program, 'sessions' were statistically significant. Based on the study results, the research and practice implications were discussed.

Effects of Computer Based Virtual Reality Program on Clinical Rehabilitation in Korea: A Meta-analysis (컴퓨터 기반 가상현실 프로그램의 국내 임상재활 적용 효과: 메타분석)

  • Kwon, Jae-Sung
    • Journal of Digital Convergence
    • /
    • v.13 no.7
    • /
    • pp.293-304
    • /
    • 2015
  • Meta-analysis was conducted to examine effects of computer based virtual reality on clinical rehabilitation in Korea. The data were analyzed as the ICF categorizations. The papers used in this study were located through domestic data search engines. The fifteen studies were selected among the studies published between 1995 and 2014. The PEDro score was used for qualitative assessment. The sample size and the average and standard deviations of pre and post tests were analyzed through a meta-analysis. The PEDro scores of the selected studies were 6 points higher and 338 participants were involved. The effect size of combined data was 1.030, activities and participation 1.120, sensory function 1.199 as indicated by a "large effect size" and the effect size of mental function was 0.557 as indicated by a "medium effect size." As a result, virtual reality program as a adjunctive therapeutic methods has proven the effect. In particular, the effects were demonstrated in activities and participation, sensory function. However there was no evidence of the effectiveness of mental function.

The Effect of Cooperative Learning and Peer Tutoring Program on Cognitive Domain and Affective Domain : A Meta-Analysis (협동학습 및 또래교수 프로그램이 수학학습부진학생의 인지적.정의적 영역에 미치는 효과 메타분석)

  • Lee, Hyeung Ju;Ko, Ho Kyung
    • Journal of Educational Research in Mathematics
    • /
    • v.25 no.1
    • /
    • pp.113-137
    • /
    • 2015
  • The objective of the present study is to systematically examine the effects of on the cognitive and affective domains of elementary, middle, and high school students by conducting a meta-analysis. To this end, this study selected 31 research papers that had analyzed the effects of applying, and performed a meta-analysis of the findings presented in each research paper. The results obtained from the meta-analysis are presented as follows. First, both the collaborative learning program and the peer tutoring program for underachieving students in math manifested an above average size of effect in the cognitive domain. In particular, the effect was the greatest at the elementary school level, and out of the two programs, peer tutoring was identified to have a sizable effect. Second, both programs displayed an above average size of effect in the affective domain, and peer tutoring was identified to have a higher effect than collaborative learning. In addition, when the programs were compared based on school levels, the size of effect was highest at the elementary school level followed by middle school and high school, in that order. When compared based on the criteria of the affective domain, self-efficacy in math, learners' attitude toward math, and learners' interest in math were identified to. Finally, this study presented suggestions for teaching underachieving students in math and conducting follow-up studies based on the analysis results.