• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.911-916
• /
• 2002

It is important to consider the effect of depth 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 reinforced concrete beam was experimentally investigated. For this purpose, a series of beam specimens subjected to 2-point bending load were tested. More specifically, three different depth (d=15, 30, and 60 cm) of 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-plan direction is not considered. The test results are fitted using least square method (LSM) to obtain parameters for modified size effect law (MSEL). The analysis results indicate that the flexural compression strength and ultimate strain decreases as the specimen size increases. Finally, more general parameters for MSEL are suggested.

• Journal of Korea Trade
• /
• v.27 no.5
• /
• pp.63-90
• /
• 2023

Purpose - This study aims to identify the relationship between logistics companies' Logistics 4.0 technology adoption with logistics innovation capability and logistics performance, and analyze the mediating effect of logistics innovation capability and the mediated moderation effect of firm size through logistics innovation capability. Design/methodology - Research models and hypotheses were established based on prior research related to Industry 4.0, Logistics 4.0, logistics technology, logistics performance, and firm size. The survey was conducted on the employees of logistics companies, and exploratory factor analysis, reliability analysis, confirmatory factor analysis, discriminant validity analysis, structural equation model analysis, mediation effect, moderation effect, and the mediated moderation effect analysis were performed. Findings - The adoption of Logistics 4.0 technology was found to significantly affect logistics innovation capability and logistics performance. Logistics innovation capability was found to significantly affect logistics performance. Moreover, logistics innovation capability was found to have a significant mediation effect on the relationship between Logistics 4.0 technology adoption and logistics performance. The moderation effect based on firm size was found to have a partial effect on logistics innovation capability and logistics performance, but the mediated moderation effect was not significant. Originality/value - This study is meaningful in that it empirically analyzed the relationship of Logistics 4.0 technology adoption with logistics innovation capability and logistics performance, the mediating effect of logistics innovation capability, the moderation effect of firm size, and the mediated moderation effect of firm size, which were not addressed in previous studies.

• Transactions of Materials Processing
• /
• v.22 no.7
• /
• pp.394-400
• /
• 2013

Microforming is a very efficient and economical technology to fabricate very small metallic parts in various applications. In order to extend the use of this forming technology for the production of microparts, the size effect, which occurs with the reduction of part size and affects the forming process significantly, must be thoroughly investigated. In this study, the tribological size effect in microforming was studied using modeling and scaled ring compression experiments. A micro-scale friction approach based on the slip-line field theory and lubricant pocket model was used to understand the friction mechanism and explain the tribological size effect. Ring compression tests were performed to analyze the interfacial friction condition from the deformation characteristics of the ring specimens. In addition, finite element analysis results were utilized to quantitatively determine the size-dependent frictional behavior of materials in various process conditions. By comparing theoretical results and experimental measurements for different size factors, the accuracy and reliability of the model were verified.

• KCI Concrete Journal
• /
• v.14 no.1
• /
• pp.43-50
• /
• 2002

In this study, size effect tests were conducted on axial compressive strength of concrete members. An experiment of Mode I failure, which is one of two representative compressive failure modes, was carried out by using dimensionally proportional cylindrical specimens (CS). An adequate notch length was taken from the experimental results obtained from the compressive strength experiment of various initial notch lengths. Utilizing the notch length, specimen sizes were then varied. In addition, new parameters for the modified size effect law (MSEL) were suggested using Levenberg-Marquardt's least square method (LSM). The test results show that size effect was apparent for axial compressive strength of cracked specimens. Namely, the effect of initial notch length on axial compressive strength size effect was apparent.

• Journal of Agricultural Extension & Community Development
• /
• v.29 no.4
• /
• pp.225-250
• /
• 2022

This study aims to examine the effects of infant's social development forest experience activities through meta-analysis. The final nine studies(total of 165 in the experimental group and 159 in the control group) were selected as a method of systematic review. Meta-analysis on overall effect size estimation, chi-square test, significance analysis, publication bias analysis, and subgroup analysis was performed using the R program. The overall effect size of 9 studies was 1.59, indicating a large effect size. As a result of subgroup analysis of the sub-factors of sociality, autonomy showed the largest effect size at 1.47, the adjusted effect size of cooperation was 1.34, the effect size adjusted for peer interaction was 1.29, and the adjusted effect size for perspective-taking ability was 0.97. All were found to have a statistically significant effect. To analyze the moderating effect, a meta-regression analysis was conducted on the participation period(4, 5~6, 7~8weeks), the number of sessions(6~10, 11~15, 16~20), the frequency per week(1, 2, 5), and the participation time(40, 60, 90, 120, 150min), but there was no statistical difference. Although not statistically significant, the effect size was larger when the participation period was 4 weeks, the number of sessions was 16 to 20, the frequency was 2 times per week, and the participation time was 40 minutes. This results can be usefully utilized by policy makers and forest commentators related to the vitalization of forest education through forest experience activities.

• Restorative Dentistry and Endodontics
• /
• v.40 no.4
• /
• pp.328-331
• /
• 2015

Though p values give information on statistical significance, they are confounded with the sample size. Effect size can make up the weak point, by providing information on the actual effect which is independent of the sample size. Therefore, reporting the effect size as well as the p value is recommended.

• Journal of the Korean Ceramic Society
• /
• v.54 no.6
• /
• pp.506-510
• /
• 2017

One of the characteristics of polycrystalline graphene that determines its material properties is grain size. Mechanical properties such as Young's modulus, yield strain and tensile strength depend on the grain size and show a reverse Hall-Petch effect at small grain size limit for some properties under certain conditions. While there is agreement on the grain size effect for Young's modulus and yield strain, certain MD simulations have led to disagreement for tensile strength. Song et al. showed a decreasing behavior for tensile strength, that is, a pseudo Hall-Petch effect for the small grain size domain up to 5 nm. On the other hand, Sha et al. showed an increasing behavior, a reverse Hall-Petch effect, for grain size domain up to 10 nm. Mortazavi et al. also showed results similar to those of Sha et al. We suspect that the main difference of these two inconsistent results is due to the different modeling. The modeling of polycrystalline graphene with regular size and (hexagonal) shape shows the pseudo Hall-Petch effect, while the modeling with random size and shape shows the reverse Hall-Petch effect. Therefore, this study is conducted to confirm that different modeling is the main reason for the different behavior of tensile strength of the polycrystalline structures. We conducted MD simulations with models derived from the Voronoi tessellation for two types of grain size distributions. One type is grains of relatively similar sizes; the other is grains of random sizes. We found that the pseudo Hall-Petch effect and the reverse Hall-Petch effect of tensile strength were consistently shown for the two different models. We suspect that this result comes from the different crack paths, which are related to the grain patterns in the models.

• Journal of Korean Academy of Nursing Administration
• /
• v.21 no.3
• /
• pp.263-276
• /
• 2015

Purpose: The study was done to verify the effect size of the variables related to the emotional labor of nurses. Methods: A total of 47 article on variables related to the emotional labor of nurses and published from 2006 to 2014 were used for the meta-analysis. Results: Variables with the largest effect size related to emotional labor were identified as the variables of work task, organization and individual characteristics in descending order of effect size. The sub-factors with the greatest effect size in the work task variable were exhaustion and work commitment, while for organization variables, intention to change jobs had the largest effect size. For individual characteristics, physical symptoms had the largest effect size. Conclusion: The results of this study are meaningful as the first study to integrate research results on variables related to the emotional labor of Korean nurses, providing practical data for the management of emotional labor.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.04a
• /
• pp.321-326
• /
• 1998

Shear failure of reinforced concrete beams is serious problem due to sudden brittle failure and many experimental results proved that size effect in shear behavior is an important feature of reinforced concrete members. For this reason, the structural safety of the reinforced concrete beams for shear has been checked by applying empirical design formula, which includes the size-effect, derived from experimental data. However, as the sizes of reinforced concrete members become extremely large, experiments sometimes become very difficult so that the formula or the experimental data could not be obtained and size-effect analyses of shear behavior become significant. In this study, size-effect analysis of shear behavior in reinforced concrete beams is performed by modeling tension stiffening/shear stiffening on reinforced concrete and the tension softening/shear softening on plain concrete. Then, the influences of models in the size-effect analyses of shear behavior in reinforced concrete beams are analyzed.

• Journal of the Korea Convergence Society
• /
• v.7 no.5
• /
• pp.145-153
• /
• 2016

The purpose of this study was using a meta-analysis to estimate effect size ACT intervention 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, 43studies were selected and 183 effect size were calculated as analysis objects. Using a 183 effect size, the overall effect size, Effect Size of categorical Factor, meta-regression result were suggested. The overall effect size of ACT program was 0.704. In the effect area of ACT, the affective domain had the largest effect size. Next were the cognitive domain, the behavioral domain. Analysis on gender of participant, mixed group had the largest effect size. Next were the female grouop, male group. Analysis on age of participant, adult group had the largest effect size. Next were the undergraduate grouop, adolescent group. Based on the findings, implications for future study were discussed.