• Title, Summary, Keyword: Effect size

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Meta analysis on the effect of reading development program on reading comprehension (독해력 증진 프로그램 효과에 대한 메타분석)

  • Lee, Hyo-Jin;Oh, Hee-Hwa;Choi, Kyoung-Ho
    • Journal of the Korean Data and Information Science Society
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    • v.23 no.3
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    • pp.447-455
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    • 2012
  • The purpose of this study is to examine the effect of reading development program on reading comprehension using meta-analysis method. The authors synthesized 70 studies regarding reading comprehension conducted during 2001 through 2011. The analyses revealed that 1) the average effect size of the reading development program yielded.763, which is regarded considerably large, 2) the effect size of elementary school group was the biggest, 1.030. There were statistically significant differences amongst school levels, 3) the average effect size of published journal articles was 1.250, which is statistically significantly larger than that of dissertation's.700, 4) regarding the methods to measure the effect of reading comprehension, the effect size of reading method was larger, and 5) the effect size of Korean reading development program was statistically larger than that of English reading development program. This study has limitation as it didn't include unpublished manuscripts, conference presentations, and the like, however this study is meaningful in terms that it tried to draw integrated conclusion about the effect of reading development programs using meta-analysis.

An Experimental Study on Reduction Effect of Scour Depth arounding Uniform Cylindrical Pier with Various Size of Circular Collar (원환 크기의 변화에 따른 균등원통교각 주위의 세굴심 감소효과에 관한 실험적 연구)

  • Sim, Ou-Bae;Song, Jai-Woo
    • Journal of Korean Society of Hazard Mitigation
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    • v.3 no.2
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    • pp.139-145
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    • 2003
  • This study is to propose reduction effect of scour depth and a optimum size of circular collar through experimental analyses with various collar sizes. To do so, we carried out hydraulic model experiments. In the case of with considering the collar, the effect of reduction of scour depth increased according to the increase of collar size. When size of collar is 2 as the ratio of collar diameter(W) to pier diameter(D), scour depth is decreased about 67% and deposition height is increased about 70%. The optimal size of collar proposed in this study is W/D=2 by analyzing reduction effect of scour depth, size of scour hole, and deposition height.

Prediction of Tensile Strength of a Large Single Anchor Considering the Size Effect

  • Kim, Kang-Sik;An, Gyeong-Hee;Kim, Jin-Keun;Lee, Kwang-soo
    • KEPCO Journal on Electric Power and Energy
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    • v.5 no.3
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    • pp.201-207
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    • 2019
  • An anchorage system is essential for most reinforced concrete structures to connect building components. Therefore, the prediction of strength of the anchor is very important issue for safety of the structures themselves as well as structural components. The prediction models in existing design codes are, however, not applicable for large anchors because they are based on the small size anchors with diameters under 50 mm. In this paper, new prediction models for strength of a single anchor, especially the tensile strength of a single anchor, is developed from the experimental results with consideration of size effect. Size effect in the existing models such as ACI or CCD method is based on the linear fracture mechanics which is very conservative way to consider the size effect. Therefore, new models are developed based on the nonlinear fracture mechanics rather than the linear fracture mechanics for more reasonable prediction. New models are proposed by the regression analysis of the experimental results and it can predict the tensile strength of both small and large anchors.

Analysis of R&D, Employment and Growth by Manufacturing Sector, Size and Export Value (기업 규모 및 수출입 수준에 따른 제조업종별 연구개발투자의 고용 및 성장성 분석)

  • Koo, Hoonyoung
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.42 no.2
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    • pp.62-68
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    • 2019
  • The growth and employment effects of R&D investment were analyzed according to business size, export value and manufacturing sectors so as to suggest improvement directions for effective industry policies. The effect of R&D investment was considered simultaneously from the two perspectives of growth and employment effect, and the causality analysis was carried out by using a path analysis. The result of the path analysis confirmed significant differences in the growth effect of R&D investment depending on business size. However, the effect of increasing employment was difficult to obtain statistically significant results for any various combinations of business size and export value. This is a mixture of directions for the effects of R&D investment on employment, which could be due to the failure to consider appropriate time lags between investment and effect. Efficiency analysis by industry sectors confirmed significant differences in efficiency depending on business size, but differences depending on export value were difficult to identify. In order to derive improvement policy by industry sector according to business size and export value, the direction of selective support policy and universal support policy was derived for six industry groups by combining the return to scale in the efficiency analysis and R&D concentration. Hirschman-Herfindahl index is used for calculating R&D concentration.

Size Effect for Flexural Compressive Strength of Concrete (콘크리트의 휨 압축강도의 크기효과)

  • Kim, Jin-Keun;Yi, Seong-Tae;Yang, Eun-Ik
    • Magazine of the Korea Concrete Institute
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    • v.11 no.2
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    • pp.157-165
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    • 1999
  • When the ultimate strength of a concrete flexural member is evaluated, the effect of member size is usually not considered. For various types of loading, however, the strength always decreases with the increment of member size. In this paper the size effect of a flexural compression member is investigated by experiments. For this purpose, a series of C-shaped specimens subjected to axial compressive load and bending moment was tested using three different sizes of specimens with a compressive strength of 528 kg/$cm^2$. According to test results the size effect on flexural compressive strength was apparent, and more distinct than that for uniaxial compressive strength of cylinders. Finally a model equation was derived using regression analyses with experimental data.

The effect of size on friction property of micro-dimple surface to fabricate by photolithography (Photolithography 를 이용한 micro-dimple 크기에 따른 미끄럼 마찰거동)

  • 채영훈;김석삼
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.217-222
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    • 2004
  • The aim of this paper is to investigate the effect of micro-dimple size on reduction friction and to understand the potential of friction reduction through micro-scale dimple to fabricate by photolithography on pin-on-disk test using flat-on-flat contact geometry. It was verify that the friction property with respect to the same pitch has been influence on the size of dimple under lubricated sliding contact. Also, we can recognize from Stribeck curve that the friction property has a connection with the size of dimple. It can explain a relationship between the friction coefficient and a dimensionless parameter for lubrication condition. The friction property has been an effect on the size of surface texture on reduction friction, not only because the density of dimple, but also because the ratio of diameter/pitch. This ratio of approximately 0.5 is recommend under the tested friction condition. It suggested that the ratio of d/p is an important parameter for surface texture design.

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Effect Analysis of Sample Size and Sampling Periods on Accuracy of Reliability Estimation Methods for One-shot Systems using Multiple Comparisons (다중비교를 이용한 샘플수와 샘플링 시점수의 원샷 시스템 신뢰도 추정방법 정확성에 대한 영향 분석)

  • Son, Young-Kap
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.4
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    • pp.435-441
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    • 2012
  • This paper provides simulation-based results of effect analysis of sample size and sampling periods on accuracy of reliability estimation methods using multiple comparisons with analysis of variance. Sum of squared errors in estimated reliability measures were evaluated through applying seven estimation methods for one-shot systems to simulated quantal-response data. Analysis of variance was implemented to investigate change in these errors according to variations of sample size and sampling periods for each estimation method, and then the effect analysis on accuracy in reliability estimation was performed using multiple comparisons based on sample size and sampling periods. An efficient way to allocate both sample size and sampling periods for reliability estimation tests of one-shot systems is proposed in this paper from the effect analysis results.

The Effect of Knowledge Management on the Innovation Activities of Employee in Small Business (중소기업의 지식경영이 구성원의 혁신활동에 미치는 효과)

  • Ahn, Kwan-Young
    • Journal of the Society of Korea Industrial and Systems Engineering
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    • v.35 no.1
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    • pp.154-160
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    • 2012
  • This paper reviewed the two proposed hypotheses. The first hypothesis is to test the relationship between knowledge management and incremental innovation, and the second hypothesis is to test the moderating effect of firm-size on that relationship. Data were gathered from 434 employees in service industry, and multiple regression analysis was used to test two proposed hypotheses. In the first hypothesis, it was appeared that knowledge acquisition and knowledge transfer have positive effects on all incremental innovation factors (process innovation, operation innovation, service innovation). In the second hypothesis, it was appeared that firm-size has an positive interaction effect on incremental innovation in knowledge transfer, but not in knowledge acquisition. It means that knowledge transfer has more positive effect on incremental innovation in large firm-size than in small firm-size.

Size Effect on Flexural Compressive Strength of Reinforced Concrete Beams (철근콘크리트 보의 휨압축강도에 대한 크기효과)

  • 김민수;김진근;이성태;김장호
    • Journal of the Korea Concrete Institute
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    • v.14 no.6
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    • pp.934-941
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    • 2002
  • It is important to consider the effect of member size when estimating the ultimate strength of a concrete flexural member because the strength always decreases with an increase of member size. In this study, the size effect of a reinforced concrete (RC) beam was experimentally investigated. For this purpose, a series of beam specimens subjected to four-point loading were tested. More specifically, three different effective depth (d$\approx$15, 30, and 60 cm) reinforced concrete beams were tested to investigate the size effect. The shear-span to depth ratio (a/d=3) and thickness (20 cm) of the specimens were kept constant where the size effect in out-of-plane direction is not considered. The test results are curve fitted using least square method (LSM) to obtain parameters for the modified size effect law (MSEL). The analysis results show that the flexural compressive strength and the ultimate strain decrease as the specimen size increases. In the future study, since $\beta_1$ value suggested by design code and ultimate strain change with specimen size variation, a more detailed analysis should be performed. Finally, parameters for MSEL are also suggested.

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
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    • v.16 no.1
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    • pp.778-784
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    • 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.