• Journal of Labour Economics
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• v.40 no.2
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• pp.31-68
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• 2017

This study examined the moonlighting behavior in Korea, to which relatively less attention has been paid. Based on the wage earners of 25 to 65 year old married, the results show that about 1.4% of the sample have dual jobs, working very long hours, on average 60 hours for a week combining both the primary job and the secondary job. The results of the fixed effects logit model on the moonlighting participation indicate that the wage rate and the hours of work in the primary job have a negative effect on moonlighting participation while the insecurity of the primary job appears to lead to a higher probability of taking a secondary job. The results of the moonlighting hours analysis suggest that hours worked in the primary job have a negative effect on moonlight hours while the wage of the primary job does not appear to have any significant effect on moonlighting hours. Interestingly enough, the wage of the secondary job appears to have a negative impact on moonlighting hours, which might be very plausible considering the long working hours moonlighters are engaged in.

• International Commerce and Information Review
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• v.16 no.2
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• pp.279-296
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• 2014

This study focused on the Technology export of Korea SMEs. Therefore this study made an empirical analysis for investigating the competitiveness of technology export in Korea SMEs and using panel data 2003-2011 of technology trade data between 72 Countries. In particular, the study deduced the correlation between technology export in Korea SMEs using the variables of Gross Domestic Expenditure on R&D and Per capita GDP, distance, population, free-trade index, firm R&D against industry value added of country, Patent grants by country to USA fixed effect model in panel linear regression model. It is found that the Technology export of Korea SMEs made a significant effect on the per-GDP, Gross Domestic Expenditure on R&D. The results suggest that the study should use technology gap variables and the strategy for activating the Technology export of Korea SMEs should be made for future works.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.8
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• pp.1-6
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• 2022

This paper uses the gravity model estimated by the random effect method to analyze the factors affecting Vietnam's coffee export turnover for the period 2007-2020 major markets according to statistics from the General Statistics Office and the General Department of Customs. Coffee export turnover was collected from the General Statistics Office, General Department of Customs, and Vietnam Cacao Coffee Association. The authors calculated the price of coffee based on output and export value from data on coffee export turnover; the authors calculated the economic gap based on population and Gross Domestic Product data (reference: geographic distance metrics on the website: http://www.distancefromto.net/countries.php) and other data was collected based on the databases of the Food and Agriculture Organization of the United Nations, the International Monetary Fund, and World Bank organizations. The results of the study show that from 2007 to 2020, the factors of Vietnam's export price of coffee, geographical distance, Gross Domestic Product of the importing country and Gross Domestic Product of Vietnam, the population of Vietnam, the economic gap between Vietnam and the importing country, the openness of the economy, all have an impact on Vietnam's coffee export turnover. Finally, some conclusions about the policy's impact are made based on the empirical results of the paper.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.190-197
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• 2000

A moment-curvature relationship to simulate the behavior of reinforced concrete beam under cyclic loading is introduced. Unlike previous moment-curvature models and the layered section approach, the proposed model takes into consideration the bond-slip effect by using monotonic moment-curvature relationship constructed on the basis of the bond-slip relation and corresponding equilibrium equation at each nodal point. In addition, the use of curved unloading and reloading branches inferred from the stress-strain relation of steel gives more exact numerical result. The advantages of the proposed model, comparing to layered section approach, may be on the reduction in calculation time and memory space in case of its application to large structures. The modification of the moment-curvature relation to reflect the fixed-end rotation and pinching effect is also introduced. Finally, correlation studies between analytical results and experimental studies are conducted to establish the validity of the proposed model.

• Journal of the Korean Statistical Society
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• v.28 no.2
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• pp.225-234
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• 1999

We consider the following semi-parametric non-linear mixed effect regression model : y\ulcorner=f($\chi$\ulcorner;$\beta$)+$\sigma$$\mu$($\chi$\ulcorner)+$\sigma$$\varepsilon$\ulcorner,i=1,…,n,y*=f($\chi$;$\beta$)+$\sigma$$\mu$($\chi$) where y'=(y\ulcorner,…,y\ulcorner) is a vector of n observations, y* is an unobserved new random variable of interest, f($\chi$;$\beta$) represents fixed effect of known functional form containing unknown parameter vector $\beta$\ulcorner=($\beta$$_1$,…,$\beta$\ulcorner), $\mu$($\chi$) is a random function of mean zero and the known covariance function r(.,.), $\varepsilon$'=($\varepsilon$$_1$,…,$\varepsilon$\ulcorner) is the set of uncorrelated measurement errors with zero mean and unit variance and $\sigma$ is an unknown dispersion(scale) parameter. On the basis of finite-sample, small-dispersion asymptotic framework, we derive an absolute lower bound for the asymptotic mean squared errors of prediction(AMSEP) of the regular-consistent non-linear predictors of the new random variable of interest y*. Then we construct an optimal predictor of y* which attains the lower bound irrespective of types of distributions of random effect $\mu$(.) and measurement errors $\varepsilon$.

• Journal of the Korean Data and Information Science Society
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• v.22 no.4
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• pp.717-726
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• 2011

The present study was carried out to summarize the effect of green tea in the diabetic rats by meta-analysis related studies. The association measure to test effect of green tea was Hedges' standardized mean difference. In this particular fixed effect model, body weight was significantly increased. Also, blood glucose, triglycerides were significantly decreased. In this case of heterogeneous variable, random effect model was applied. In this model, body weight was significantly increased. Also, blood glucose was significantly decreased in green tea treated group. According to the Meta-regression analysis, duration of injection was not significant for variables.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.898-904
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• 2003

This study was conducted to observe the effect of various kinds of sugars and their molar concentrations on the Maillard browning reaction. To observe the effects of various kinds of sugar, glucose, fructose, tagatose, xylose, and sucrose were employed. A model solution consisting of 0.2 M sugar and 0.2 M glycine was prepared and heated at $100^{\circ}C$ for 5 hr. The model solution with adjusted concentrations of either tagatose or glycine was also heated at $100^{\circ}C$ for 5 hr. Tagatose showed the fastest Maillard reaction, followed by xylose, fructose, glucose, and sucrose. After glycine concentration of the model solution was fixed, the model solution showed more browning with an increase in tagatose concentration. When the tagatose concentration of the model solution was fixed, the model solution showed more browning with an increase in glycine concentration. The model solution with a fixed concentration of glycine showed more more browning than that with a fixed concentration of tagatose, since the former had higher amounts of the reactant.

• Structural Engineering and Mechanics
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• v.69 no.6
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• pp.699-712
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• 2019

A cable-stayed bridge (CSB) is one of the most complicated structures, especially when subjected to earthquakes and taking into consideration the effect of soil-structure-interaction (SSI). A CSB of a 500 m mid-span was modeled by the SAP2000 software and was subjected to four different earthquakes. To mitigate the harmful effect of the vibration generated from each earthquake, four mitigation schemes were used and compared with the non-mitigation model to determine the effectiveness of each scheme, when applying on the SSI or fixed CSB models. For earthquake mitigation, tuned mass damper (TMD) systems and spring dampers with different placements were used to help reduce the seismic response of the CBS model. The pylons, the mid-span of the deck and the pylon-deck connections are the best TMDs and spring dampers placements to achieve an effective reduction of the earthquake response on such bridges.

• SUVANNABHUMI
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• v.15 no.2
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• pp.215-244
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• 2023

This study analyzes the effect of macroeconomic indicators such as foreign direct investment (FDI), domestic investment, trade, inflation, unemployment, population, and governance indicators on economic growth and points out the GDP growth rate in 2002- 2019 among ASEAN countries. Data were compiled from the Worldwide Governance Indicators (WGI) and the World Bank, and the effect of variables on GDP was predicted using the pooled ordinary least squares (POLS), fixed effects model (FEM), and random effects model (REM) methods. As a measure of growth, the GDP growth rate has been taken; FDI and domestic investment, trade, inflation, and governance indicators are positively connected and have an influence on economic growth in these ASEAN countries; domestic investment, population, and unemployment have a negative relationship to economic growth. The macroeconomic indicators and institutional stability of the nation have an effect on its economic growth. Comprehensive institutional stability and well-laid macroeconomic policies are required for growth to materialize.

• Structural Engineering and Mechanics
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• v.45 no.6
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• pp.741-758
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• 2013

In this study, inelastic displacement ratios are investigated for existing systems with known lateral strength considering soil structure interaction. For this purpose, SDOF systems for period range of 0.1-3.0 s with different hysteretic behaviors are considered for a number of 18 earthquake motions recorded on soft soil. The effect of stiffness degradation on inelastic displacement ratios is investigated. The Modified Clough model is used to represent structures that exhibit significant stiffness degradation when subjected to reverse cyclic loading and the elastoplastic model is used to represent non-degrading structures. Soil structure interaction analyses are conducted by means of equivalent fixed base model effective period, effective damping and effective ductility values differing from fixed-base case. For inelastic time history analyses, Newmark method for step by step time integration was adapted in an in-house computer program. A new equation is proposed for inelastic displacement ratio of system with SSI with elastoplastic or degrading behavior as a function of structural period ($\tilde{T}$), strength reduction factor (R) and period lengthening ratio ($\tilde{T}$/T). The proposed equation for $\tilde{C}_R$ which takes the soil-structure interaction into account should be useful in estimating the inelastic deformation of existing structures with known lateral strength.