• Structural Engineering and Mechanics
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• v.76 no.1
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• pp.27-56
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• 2020

In this paper, the deflection and buckling analyses of porous nano-composite piezoelectric plate reinforced by carbon nanotube (CNT) are studied. The equations of equilibrium using energy method are derived from principle of minimum total potential energy. In the research, the non-local strain gradient theory is employed to consider size dependent effect for porous nanocomposite piezoelectric plate. The effects of material length scale parameter, Eringen's nonlocal parameter, porosity coefficient and aspect ratio on the deflection and critical buckling load are investigated. The results indicate that the effect of porosity coefficient on the increase of the deflection and critical buckling load is greatly higher than the other parameters effect, and size effect including nonlocal parameter and the material length scale parameter have a lower effect on the deflection increase with respect to the porosity coefficient, respectively and vice versa for critical buckling load. Porous nanocomposites are used in various engineering fields such as aerospace, medical industries and water refinery.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.391-402
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• 2016

The purpose of this study is to use meta-analysis as a research method to investigate the correlation between early child teachers' teaching efficacy and their job satisfaction, and thereby look into the effect size of the two variables and their sub-variables. To achieve the purpose, this researcher chose a total of 37 theses for analysis and collected 289 data for analyzing the effect size. Based on the data, CMA(Comprehensive Meta Analysis) 2.0 was applied. According to the analysis, the correlation between early childhood teachers' teaching efficacy and their job satisfaction was higher than the medium effect size on the basis of Cohen(1992) research. In the sub-variables of teaching efficacy, the correlation of personal teaching efficacy with job satisfaction showed higher effect size than that of general teaching efficacy. In the sub-variables of job satisfaction, the correlation between the belief in job and teaching efficacy showed the highest effect size. In terms of thesis type as a moderating variable, Ph.D dissertations showed higher effect size than journals or M.A. theses. As the result of the meta-analysis on publishing year and the number of samples, there was no statistical significance. On the basis of the analysis results, discussions and limitations of this study were suggested.

• Journal of Korea Trade
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• v.23 no.4
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• pp.30-57
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• 2019

Purpose - This study analyzes the effect of internationalization represented as exporting on firm performance on the subject of SMEs operating in Masan Free Trade Zone which has shown poor performance recently despite its status as the oldest and largest free trade zone in Korea. We also analyze the effect of firm size on firm performance, and the moderating role of firm size in relation to internationalization and firm performance. Design/methodology - This study uses multiple regression models for unbalanced panel data as the empirical tools for the estimation of the effect that internationalization has on firm performance (ROA or ROS). Our sample consists of 91 manufacturing SMEs among all 110 companies located in Masan Free Trade Zone as of 2017. Findings - The degree of internationalization has a negative impact on firm performance. However, firm size turns out to have a positive effect and play a positive moderating role in the relation to internationalization and firm performance. This seems to be because most tenant companies operating in Masan Free Trade Zone are small firms whose costs of internationalization may exceed the benefits. Empirical results also show that longer CEO tenure has a greater negative effect on firm performance. Originality/value - The originality/value of this paper can be found in 3 aspects. First, we conducted an empirical analysis on the relationship between the internationalization and firm performance of SMEs in a specific region, namely, Masan Free Trade Zone. Second, while most previous studies focused on listed medium companies, most of the sample of this study are small and medium non-listed enterprises. Third, it is witnessed that firm size has a positive moderating effect on the relation between internationalization and firm performance.

• The Journal of the Korea Contents Association
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• v.19 no.9
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• pp.338-347
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• 2019

The purpose of this study is to provide policy and adaptive interventions for quality of life of the elderly and evidence-based data. For this, meta-analysis was performed using CMA program, and the final 65 researches were used for analysis. The results, (1)The risk factors(depression, solitude, anxiety, suicidal Ideation, stress) showed the effect size which is suitable for quality of life. The effect size of depression was the highest. (2)The protective factors(self-esteem, self-efficacy) showed medium effect size and large effect size. Among them, self-esteem showed the greatest effect size of quality of life. However, self - control appeared to have a low effect size.

• Steel and Composite Structures
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• v.15 no.2
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• pp.151-162
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• 2013

In this study, an electrolyzing device for the production of metal powders was designed and fabricated. The production of copper powders was performed using a variety of current densities, anode-cathode distances and power removal times. The effect of these parameters on powder particle size and shape was determined. Particle size was measured using a laser diffraction unit while the powder shape was determined by SEM. Experimental results show that an increase in current density leads to a decrease in powder particle size. In addition particle shape changed from globular dendritic to acicular dendritic with increasing the current density. Distance between the cathode and anode also showed a similar influence on powder particle size and shape. An increase in time of powder removal led to an increase in powder particle size, as the shape changed from acicular dendritic to globular dendritic.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.1
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• pp.72-81
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• 2004

Study on the analysis of sodium spray fire using Gaussian drop size distribution, which redistributes a droplet spectrum with given mean diameter if its size classes with critical diameter(D>8mm) occur, was carried out. In this case, the oversized droplets were reduced to a stable diameter. Results calculated by the code using Gaussian drop size distribution were in better agreement with AI experimental results than those of NACOM and SPRAY code. The effect of variance on pressure in the test cell appeared greatly by introducing Gaussian function, which could represent various sodium droplet size distribution. The increase of the variance with mean droplet size resulted had an important effect upon the pressure in the test cell.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.285-288
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• 2000

The effect of the initial BSCCO 2212 grain size on the final gain size and the formation of the BSCCO 2223 was studied using a powder precursor synthesized by two-powder method. 2212 and CaCuO$_2$ tapes were prepared by dip coating and joined by pressing and then followed by the repeated thermo mechanical treatment. The samples were characterized by XRD and SEM analysis. The formation and grain size of the BSCCO 2223 depended on the initial BSCCO 2212 grain size.

• Journal of Power System Engineering
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• v.4 no.2
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• pp.40-45
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• 2000

Some engineering materials are often known to have considerable spatial variation in their resisting strength and other properties. The objective of this study is to investigate the averaging effect and the applicability of extremal statistic for the statistical size effect. In the present study, it is assumed that the material property is a stationary random process in space. The theoretical autocorrelation function of the material strength are discussed for several correlation lengths. And, in order to investigate the statistical size effect, the material properties was simulated by using the non-Gaussian random process method. The material properties were plotted on the Weibull probability papers. The main results are summarized as follows: The autocorrelation function of the material properties are almost independent of the averaging length. The variance decreases with increasing the averaging length. As correlation length is smaller, the slope is larger. And also, it was found that Weibull statistics based on the weakest-link model could not explain the spatial variation of material properties with respect to the size effect satisfactory.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1879-1890
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• 2011

Previous studies of syllable frequency effects have proposed that inhibitory effects due to high first syllable frequency were the products of competitions between activated lexical candidates within a lexical level. However, these studies have primarily used lexical decision tasks to examine the nature of syllable frequency effects. This study investigates whether a syllable frequency effect can arise in semantic categorization tasks and whether phonologically or orthographically defined syllables interact with semantically related variables such as morphological family size. If the syllable frequency effect was created by activations and competitions on a lexical level, it is highly possible that the effect was related to semantic categorization tasks. To test this hypothesis, we conducted two experiments. In Experiment 1, morphological family size and phonological syllable frequency were factorially manipulated. In Experiment 2, morphological family size and orthographic syllable frequency were factorially manipulated. The results demonstrate that morphemes have no relationship with phonological syllables but do with orthographic syllables. This suggests that phonological syllables and orthographic syllables have different roles in the syllable frequency effect on visual word recognition process.

• Asia-Pacific Journal of Business
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• v.9 no.3
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• pp.117-137
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• 2018

Lots of the studies about the relationship between coaching leadership and organizational effectiveness have been conducted and reported that coaching leadership is one of the main factors which impact organizational effectiveness. The purpose of this study was to synthesize the relationship between coaching leadership and organizational effectiveness. For that purpose, 32 correlation effect sizes from 25 studies were analyzed by the CMA (Comprehensive Meta-analysis) Program. The study calculated the overall effect size of the relationship between coaching leadership and organizational effectiveness. Then, it also calculated the effect size of the relationship between coaching leadership and each sub-variable of organizational effectiveness. The analysis results are as follows: First, the overall effect size about the relationship between coaching leadership and organizational effectiveness was .519, which means that coaching leadership has over lager relationship with organizational effectiveness. In addition, the effect sizes of sub-variables of the organization are .556 (organizational commitment) .542 (job satisfaction), 509 (organizational citizen behavior), and .401 (innovative behavior). The study tested the mediating effects of measurements, organizational size, types of publication, and published year. The result showed that only the measurement made significant differences among effect sizes of studies.