• Resources Recycling
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• v.31 no.5
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• pp.52-58
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• 2022

Silicon carbide powder was prepared from carbon black and silicon recovered from waste solar panels. In the solar power generation market, the number of crystalline silicon modules exceeds 90%. As the expiration date of a photovoltaic module arrives, the development of technology for recovering and utilizing silicon is very important from an environmental and economic point of view. In this study, silicon was recovered as silicon carbide from waste solar panels: 99.99% silicon powder was recovered through purification from a 95.74% purity waste silicon wafer. To examine the synthesis characteristics of SiC powder, purified 99.99% silicon powder and carbon powder were mixed and heat-treated (1,300, 1,400 and 1,500 ℃) in an Ar atmosphere. The characteristics of silicon and silicon carbide powders were analyzed using particle size distribution analyzer, XRD, SEM, ICP, FT-IR, and Raman analysis.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.277-285
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• 2022

The purpose of this study is to analyze and verify the effect of multicultural adolescents parental support and parenting attitudes on school life and social competency by using the primary data of the second period of the MAPS(Multicultural Adolescents Panel Study). The subject of this study in 2019 was 2,246 multicultural adolescents who were in the fourth grade of elementary school at the time. As a result of the study, it was found that the more positive and positive parental support and parenting attitude were, the higher the degree of school life and social competence of multicultural adolescents. On the other hand, the degree of school life and social competence varies according to gender, and it was found that female students were higher than male students. There was a significant difference in the degree of school life according to the mother's educational background, but there was no significant difference in the degree of social competence. These results suggest that parental support and parenting attitudes are major environmental variables in the educational ecosystem that affect the school life and social competence of multicultural adolescents.

• 한국노년학
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• v.38 no.4
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• pp.811-835
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• 2018

Social relations and cognitive function in old age are closely related to each other, and social relation is classified into structural characteristics and qualitative characteristics reflecting cognitive and emotional evaluation. The concept of social isolation is the focus of attention in relation to the social relations of old age. Social isolation has a multidimensional theoretical structure that is divided into objective dimension such as social network, type of furniture, social participation, and subjective dimension such as lack of perceived social support and loneliness. There is also a close relationship between cognitive function and interpersonal conflict in old age. In this study, we examined the effect of subjective social isolation, which shows the structural characteristics of social relations, and subjective social isolation and interpersonal conflict on the dementia occurrence by age group in the elderly. The data were analyzed by applying a random effect panel logit model using 1,740 panel data from the first year to the third year of KSHAP. The results of the analysis are summarized as follows. First, the cognitive impairment increased sharply with age. Objective and subjective social isolation were both U-shaped distribution with an inflection point of 80 years old. Second, the main effect on the probability of cognitive impairment was statistically significant with objective and subjective social isolation, but the type of interpersonal conflict did not appear to be significant. Third, the results of two-way interaction effect analysis on the probability of cognitive impairment are as follows. The relationship between subjective social isolation and the probability of occurrence of cognitive impairment was significantly different according to the level of conflict with spouse. In addition, the higher the subjective social isolation, the higher the probability of cognitive impairment in the elderly(over 85) than in the young-old(65~74). In addition, as the level of conflict with spouses increases, the probability of cognitive impairment of the oldest-old(aged 85 or older) is drastically lower than that of the young-old(aged 65~74). Based on the results of this study, policy and practical implications for reducing the cognitive impairment of the elderly age group were suggested, and limitations of the study and suggestions for future research were discussed.

• Journal of Labour Economics
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• v.30 no.2
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• pp.1-31
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• 2007

The purpose of this paper is to analyse wage differentials between non-regular and regular works. Data from EAPS(Economically Active Population Survey) 2005 show that the monthly wage level of non-regular worker is only 63% of regular worker and thus there exist 37% wage differentials. However, these wage differentials do not control for hours of work, the amount of human capital, job characteristics, and other individual characteristics affecting wages. If these variables are added to the hourly wage regression equation, the wage gap between non-regular and regular workers drastically decreases to 2.2%. Furthermore, decomposition of the wage differentials by Oaxaca method shows that productivity difference between non-regular and regular workers explains up to 91% of the wage gap. This implies that the magnitude of wage discrimination against non-regular workers is at most 0.2% of hourly wage of regular workers. To control for unobserved individual heterogeneities more accurately, we also construct panel data and estimate wage differentials. The results from the panel data approach show that there is no difference in the hourly wages between non-regular and regular workers. In some specifications, the wage rate of non-regular worker is rather higher than that of regular worker. These results are consistent with economic theory. Other things being equal, workers with unstable employment may require higher wages to compensate their unstability. Firms are willing to pay higher wages if they can get more flexibility from non-regular employment. Empirical results in this paper cast doubt on the view that there is wage discrimination against non-regular workers in the labor market. Public policies should be targeted for disadvantaged groups among non-regular workers, not for non-regular workers in general.

• International Area Studies Review
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• v.15 no.2
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• pp.151-173
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• 2011

The purpose of this paper is to examine the impact of production factors on economic growth in China during 1979~2008. In order to grasp the determinant and contribution analysis, we take fixed effect model and random effect model and Hausman test to choice model. The results show that the finance variable (rsav) and SOC variable (rsoc) have negative effects on the economic growth in the long run except some models. But unimproved raw labor variable (rlab), physical capital variable (rcap) and education variable (redu) shows strongly positive effect for the same time. We found the meaning of coefficients of growth factors. relative contribution of each input to per-capita growth in China. The direct elative contribution of physical investment to per-capita growth gives 35.9 percent in total model (TMO) and unimproved raw labor contributes only 4.7 percent. In all modes, physical investment (rcap) was the most important contributor of predicted growth in China economy.

• Korean Journal of Social Welfare Studies
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• v.40 no.1
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• pp.235-260
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• 2009

This study aims to analyze consumption inequality of Korean elderly households. The justification for analyzing consumption inequality during old age could be summarized as follows. First, due to the rapid growth of elderly population, the intra generational inequality of older people will bring greater consequences to the society in the coming years. Second, inequality is more actualized during old age when income stops playing a major role and the everyday lives are based mostly on consumption activities. For analysis, this study used the 2nd, 5th, 7th and 9th wave of 『Korea Labor and Income Panel Study』. The findings are as follows. First, total consumption inequality of elderly households is gradually decreasing after the economic crisis. Also, the gini coefficient of consumption items representing modern consumption culture, such as expenditures on eating out and car maintenance is decreasing. However, the inequality contribution rate of such items is continually rising, indicating that whereas the elderly households in general are being assimilated to the mainstream consumption culture, the disparity between classes is continually expanding. Second, gini coefficient and inequality contribution rate of the essentials such as food and housing has decreased indicating that basic livelihoods in general has risen. Third, the inequality of education expenditure is increasing after the year 2000 which implies that the problem of education inequality in general might have an effect on elderly households.

• 한국노년학
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• v.41 no.1
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• pp.49-68
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• 2021

The present study aims to examine the mediating role of life satisfaction in the relationship between productive activities and future time perspective in later life. Drawn from the 7^th wave of the Korea Longitudinal Study of Aging, our sample consists of a total of 6,756 older adults aged 55 and over. Complex samples analyses were conducted the relationship between productive activities, life satisfaction and future time perspective measured in two dimensions (i. e., life expectancy and job expectation). Results from complex samples analysis showed that productive activities were associated with life satisfaction and future time perspective. Employed older adults including unpaid family workers tended to have higher levels of life satisfaction and future time perspective (i.e., life expectancy and job expectation) than their counterparts. The relationship between productive activities and future time perspective was mediated by life satisfaction. Findings suggest that engaging in productive activities influences better satisfaction with life among older adults, which is eventually linked to an expansive view of the future. Policy implications were discussed that promoting productive activities in later life and age-friendly working environment should be encouraged.

• Environmental and Resource Economics Review
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• v.25 no.3
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• pp.449-470
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• 2016

This paper analyzes the effects of nuclear power generation on industrial growth in using the data of 22 manufacturing sectors in 14 nuclear power countries. The hypothesis that the change in the proportion of nuclear power generation in total electricity generation affects industrial value-added and industrial output through industrial electricity price reduction was tested using the dynamic panel data model. First, it was estimated that the increase in nuclear power generation by a 1% leads to a 0.8% reduction in electricity price. The results indicate that when nuclear power generation increased by a 1% point, industrial value-added and output increased by 0.16% and 0.23%,respectively, in the short-run and by 0.51% and 0.85%, respectively, in the long-run. It was also inferred that the effect of nuclear generation on industrial competitiveness working through electricity price reduction rely on institutional settings in the electricity markets. That is, the competitive effect is greater in the countries such as U.K and Japan where electricity price is high and price volatility is large. Meanwhile, in Germany which has pursued phasing out nuclear power, industrial competitiveness is promoted through stable electricity supply.

• 한국사회정책
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• v.25 no.4
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• pp.125-161
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• 2018

This article aims to investigate the impact of Korean employment protection legislation that has implemented since 2007 on eliminating discrimination on non-regular worker's wage and social security. It is used the panel Tobit model reflecting the variation of implementation time according to the size of establishments. Although the employment protection laws for non-regular workers have implemented, the wage gap and discrimination in social security for non-regular workers have continued. Of course, the discrepancies on wage and social security were founded not only between regular and non-regular workers but also within non-regular workers. For reducing the discriminations, this study proposes to restrict the reason for justifying discrimination, and the introduction of a new approach to accessing the discrimination and complimentary credit system. Besides, this study suggests to actively review the strengthening of regulations on the use of non-regular workers.

• Korean Journal of Social Welfare Studies
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• no.39
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• pp.5-28
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• 2008

The purpose of this study is two-fold: 1) to identify different adolescent smoking trajectories in Korea; and 2) to examine predictors of those smoking trajectories within a social developmental frame. Data were from the Korea Youth Panel Survey(KYPS), a longitudinal study of 3,449 youths followed since 2003. Using semi-parametric group-based modeling, four smoking trajectories were identified: non initiators, late onsetters, experimenters, and escalators. Multinomial logistic regressions were then used to identify risk and protective factors that distinguish the trajectory groups from one another. Among non smokers at age 13, late onsetters were distinguished from non initiators by a variety of factors in every ecological domain. Among youths who already smoked at age 13, escalators who increased their smoking were distinguished from experimenters who almost desisted from smoking by age 17 by self-esteem and academic achievement. Finally, implications for youth welfare practice from this study were discussed.