• 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.

• 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.

• Journal of Practical Engineering Education
• /
• v.12 no.1
• /
• pp.41-47
• /
• 2020

This study aims to investigate effects of brain-based learning. 27 primary studies were selected through rigorous search process and analyzed through meta-analytic methods. Research findings are as follows. First, the total effect size was .67. Second, the effect of dependent variables was academic achievement, cognitive domain, and affective domain in order. Third, with respect to types of cognitive domain, the effect was self-regulation, creativity, competence, communication, and research ability in order. Fourth, the effect of affective domains was sociality, learning interest, and subject attitude in order. Fifth, regarding development of cognitive ability, the effect size was combined, brain training, learning environments, and right brain activities in order. Sixth, the effect of learning activities was memory improvement and attention enhancement in order.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7273-7284
• /
• 2015

The purpose of this study was to investigate the effect size of non-pharmacological intervention applied to patients with anxiety disorder and to provide information about evidence-based intervention. Twenty three studies were selected for meta-analysis through a systematic review of domestic studies. We searched journal articles published in Korea up to May, 2015 using the key words "Anxiety Disorders (MeSH)" and "Treatment or Intervention". Meta-analysis was performed using a random effects model, and the effect sizes on each of anxiety and depression were calculated. The effect size for anxiety of non-pharmacological intervention in this study was Hedges' g=1.693 (95% CI; 1.267-2.120), indicating a large effect size. The effect size for depression was Hedges's g=1.571 (95% CI; 0.481-2.661), indicating a large effect size. It is significant that this study systematically synthesized the study results for non-pharmacological intervention effects applied to patients with anxiety disorders in Korea. It also established a basis that can be applied to nursing intervention.

• The Journal of the Korea Contents Association
• /
• v.16 no.8
• /
• pp.756-765
• /
• 2016

In order to investigate variables related to the life satisfaction of women from the multi-cultural families, this study collected relevant studies and applied meta-analysis. As a result, it was found, first, their life satisfaction was between the small effect size and the moderate effect size, on the basis of the relevant variables and Cohen's standards(1992). Second, of the sub variables of their individual characteristic variable, Korean proficiency and nationality acquisition were found to be the small effect size. Third, of the sub variables of their psychological variable and multiple culture-related variable, the effect sizes of self-esteem and the receptive attitude towards multiple cultures were found to be between the moderate effect size and the large effect size. Fourth, the sub variables of their social support variable were found to be generally highly correlated with their life satisfaction. Fifth, the sub variables of daily life and spouse-related variables showed very low levels of effect size overall. This study suggested conclusions and limitations of the research based on the results of the above analyses.

• Journal of Digital Convergence
• /
• v.15 no.12
• /
• pp.25-33
• /
• 2017

The purpose of this study was using a meta-analysis to estimate effect size of emotional intelligence program. Using a statistical method, meta-analysis has advantages that prove intervention's amount and direction. Meta-analysis facilitates comprehensive analysis. Through the data collection, 33studies were selected and 92 effect size were calculated as analysis objects. The overall effect size of emotional intelligence program was 0.839. Depend on subordinate scope, the emotional cognition had the largest effect size. Next were the understanding domain, application domain, the regulation domain and the expression domain. Analysis on age of participant, adult group had the largest effect size. Next were the elementary students group and the adolescent group. Based on the findings, implications for future study were discussed.

• Journal of Digital Convergence
• /
• v.19 no.4
• /
• pp.443-455
• /
• 2021

The purpose of this study was attempted to conduct a meta-analysis on the antecedents factors of transformational leadership of nursing unit managers. Literature was collected according to the PRISMA guidelines, and the antecedent factors of 23 studies were analyzed. The results showed that the total 23 studies large effect size (ESzr=.54). Antecedent factors were classified into three categories, and the organization-related variables group had the largest effect size (ESzr=.56). This study is an integrated presentation of the effect size of the antecedent factors of transformational leadership through a meta-analysis and the results of this study are expected to be used as a basis for developing intervention programs for nursing unit managers' transformational leadership improvement.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.116-116
• /
• 2010

단일 양자점의 특성 분석 및 이를 활용한 단광자 광원 등으로의 응용에 있어서 표면밀도 및 크기 등이 의도대로 조절된 양자점 성장이 필수적이며, 이와 관련하여 근적외선 파장 영역에서 발광 성분을 갖는 InGaAs/GaAs 양자점 시료를 MEE (Migration Enhanced Epitaxy) 기법으로 성장하였다. 이 때, 30 초 120 초 사이의 migration enhancing time 변화에 의하여 약 $350\;QDs/{\mu}m^2$에서 $3\;QDs/{\mu}m^2$ 사이의 범위로 양자점 표면 밀도가 조절되었으며 양자점의 크기도 변화하는 것을 확인하였다. 별도로 capping layer를 성장하지 않은 양자점 층에 대한 AFM 측정을 통하여 양자점의 크기를 예측하였으나, 실제 시료의 양자점 크기는 capping layer 성장시의 온도 및 압력에 따른 영향이나 물질 조성의 불균일성 등으로 인해 달라질 수 있으므로 비파괴 검사방법인 광발광 측정으로써 실제 양자점의 특성을 검증할 필요성이 존재한다. 먼저 양자점의 크기가 커짐에 따라 기저상태의 에너지 밴드갭 크기가 감소하는 경향이 있음을 확인하였다. 이는 양자점이 클수록 양자구속 효과가 작아지는 일반적인 경향과 일치한다. 또한, 양자점의 크기 차이에 따른 기저상태 및 고차 여기 상태의 에너지 밴드갭 차이의 변화 경향을 분석하였다. 일반적으로 양자점의 크기가 줄어들면 양자구속효과 또한 빠르게 증가하다가 결국에는 에너지 장벽(barrier)의 에너지 준위에서 포화상태에 도달하게 된다. 이러한 양자점 크기에 따른 양자구속효과 크기의 변화는 고차 여기 상태일수록 더욱 빠르며, 결국에는 양자 구속효과가 없어지는 상태(unbound exciton)에 이르기도 한다. 따라서 기저상태의 에너지 밴드갭은 양자점이 커짐에 따라 단조감소 경향을 보이나, 변화율의 차이 때문에 기저상태와 1차 여기상태의 에너지 차이인 level spacing 값은 단조감소 경향이 아닌 종 모양의 경향성을 보이며 측정 결과 또한 이와 일치하였다. 이와 같이 migration enhancing time의 조절로 광자와 상호작용하는 실질적인 양자점의 크기가 의도대로 조절되었음을 비파괴 광측정법으로 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.10
• /
• pp.1463-1470
• /
• 2010

Microforming, which exploits the advantages of metal forming technology, appears very promising in manufacturing microparts since it enables the production of parts using various materials at a high production rate, it has high material utilization efficiency, and it facilitates the production of parts with excellent mechanical properties. However, the conventional macroscale forming process cannot be simply scaled down to the micro-scale process on the basis of the extensive results and know-how on the macroscale process. This is because a so-called "size effect" occurs as the part size decreases to the microscale. In this paper, we attempt to develop an effective analytical and experimental modeling technique for explaining the effects of the grain size and the specimen size on the behavior of metals in microscale deformation processes. Copper sheet specimens of different thicknesses were prepared and heat-treated to obtain various grain sizes for the experiments. Tensile tests were conducted to investigate the influence of specimen thickness and grain size on the flow stress of the material. In addition, an analytical model was developed on the basis of phenomenological experimental findings to quantify the effects of the grain size and the specimen size on the flow stress of the material in microscale and macroscale forming.

• Journal of Practical Engineering Education
• /
• v.14 no.3
• /
• pp.505-512
• /
• 2022

The purpose of this study is to synthesize effects of the living lab-based education through meta-analysis. Seven primary studies reporting the effect of living lab-based education were carefully selected for data analysis. Research questions are as follows. First, what is the overall effect size of the living lab-based education? The overall effect size refers to the effect on the cognitive and affective domains. Second, what is the effect size of the living lab-based education according to categorical variables? Categorical variables are outcome characteristics, study characteristics, and design characteristics. Results are summarized as follows. First, the overall effect size of living lab-based education was 0.347. Second, the effect size according to the cognitive domain was 1.244 for information process, 0.593 for communication, 0.261 for problem solving, and 0.26 for creativity. Third, the effect size according to subject area was shown in the order of electrical and electronic engineering 1.146, technology and home economics 0.489, artificial intelligence 0.379, and practical arts 0.168. Fourth, the effect size according to school level was 1.058 for high school, 0.312 for middle school, and 0.217 for elementary school. Fifth, the effect size by grade level was 0.295 when two or more grades were integrated and 0.294 for a single grade.