• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.704-707
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• 1999

Partial discharge(PD) in air insulated electric power systems is responsible for considerable power lossesfrom high voltage transmission lines. PD in air often leads to deterioration of insulation by the combined action of the discharge ions bombarding the surface and the action of chemical compounds that are formed by the discharge and may give rise to interference in ommunication systems. PD can indicate incipient failure. Thus understanding and classification of PD in air is very important to discern source of PD. In this paper, we investigated PD in air by using statical method. We classified air discharge with corona, surface discharge and cavity discharge by source of discharge. we used the mean pulse-height phase distribution $H_{qmean}(\psi)$, the max pulse-height phase distribution $H_{qmax}(\psi)$ , the pulse count phase distribution $H_n(\psi)$ and the max pulse height vs. repetition rate $H_{q}(n)$ for analysis PD pattern. We used statistical operators, such as skewness(S+. S-1, kurtosis(K+, K-), mean phase(AP+. AP-), cross-correlation factor(CC) and asymmetry from the distribution.

• Journal of Environmental Science International
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• v.29 no.5
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• pp.445-455
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• 2020

Fine dust is one of the most critical environmental issues in Korea, and the government recognizes the need to establish customized reduction policies based on regional characteristics. Several studies on air pollutants investigate whether factories affect the distribution of fine dust in a particular region. However, understanding the impact of the entire industry sector requires further investigation. This study identifies the impacts of industrial characteristics on fine dust levels of 141 municipalities across Korea in 2016. A total of 23 variables were used, of which 12 referred to industries and 11 to general characteristics of each city. Due to the high correlation between independent variables, partial least squares (PLS) regression models were used. The analysis identified 14 significant variables for PM10 and 13 for PM2.5. Therefore, the results suggest that local industrial characteristics can significantly influence fine dust levels and provide suggestions for establishing customized reduction policies based on local characteristics.

• Journal of Korean Academy of Psychiatric and Mental Health Nursing
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• v.27 no.4
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• pp.332-341
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• 2018

Purpose: The purpose of this study was to determine the impacts of vocational calling, emotional intelligence, and major commitment on nursing college students' happiness. This study also was conducted to explore major commitment's mediating effect on the relationship between vocational calling, emotional intelligence, and major commitment among nursing college students. Methods: Participants were 346 nursing college students. Data were collected in November, 2017 with self-report questionnaires and were analyzed using t-test, one-way ANOVA, Pearson's correlation coefficients, and regression analysis with IBM SPSS 19.0. Results: The regression model explained 33.0% of variance in nursing college students' happiness (F=41.44, p<.001). Significant factors were emotional intelligence (${\beta}=.30$, p<.001), grade (${\beta}=.20$, p<.001), major commitment (${\beta}=.18$, p=.002), and vocational calling (${\beta}=.11$, p=.035). Moreover, major commitment showed partial mediating effects on vocational calling and happiness. Major commitment also showed partial mediating effects on emotional intelligence and happiness. Conclusion: The results suggest that nursing college students' happiness can be increased through strategies aimed at increasing vocational calling, emotional intelligence, and major commitment.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.179-184
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• 2005

Shear strength parameters obtained from filed survey are important factors in the analysis of slope stability. In this study, sensitivity analysis was performed to evaluate the effect of input parameters on the analysis of slope stability. The input parameters selected for sensitivity analysis were slope angle, cohesion, and friction angle. Monte-Carlo Simulation method was used for calculating input parameters and the factor of safety was computed by means of limit equilibrium method. A rock slope, which has failed in the field, was used for the sensitivity analysis in the analysis of slope stability. The result of analysis shows that the factor of safety of the rock slope was a little low. From partial correlation coefficient(PPC) of input parameters determined from the sensitivity analysis, slope stability was dependant on cohesion and slope angle. The effect of friction angle was lower than that of cohesion and slope angle on slope stability.

• Korean Journal of Child Studies
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• v.30 no.2
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• pp.211-229
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• 2009

This study examined replication of the factor structure of the DAPC [Domain-specific Assessment of Psychological Control (Soenens et al., 2006)] in parents of Korean adolescents. Participants included 289 adolescents who responded to DAPC items regarding their parents' psychological control behaviors. Two factors comprising 17 items were identified and labeled as "achievement oriented psychological control", and "separation-anxious psychological control." Confirmatory factor analysis and partial correlation analysis provided evidence for the construct validity of the DAPC through construct reliability, convergent validity and discriminant validity across both sex of parents and adolescents. The psychometric properties indicated that DAPC could be useful in studying parents' psychological control behaviors toward their adolescent children.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.298-303
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• 2003

The eccentric rotor system has various problems by vibration of unbalance mass. Specially, it is difficult to analyze vibration problem for the drum washing machine due to correlation of transmission paths. We analyze the mechanical structure by multidimensional spectral density to identify the maximum vibration magnitude at the frequency domain. It estimates the coherence function of the signals to pass the transmission paths. In case of the drum washing machine, because the transmission paths are correlated partially it needs to determinate the priority ranking. And the correlated parts are eliminated using conditioned spectral density function. Finally the shielding effect method confirms the reasonability of the modeling.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1199-1203
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• 2009

Melamine is a chemical intermediate to manufacture amino resins and plastics, which cannot be used as food additive since it can cause kidney stones. A qualitative determination method of melamine residue in powdered and liquid milk was developed using Fourier transform infrared (FTIR) spectroscopic technique. The calibration sets consisted of 21 standard melamine solutions, in which 1% trichloroacetic acid aqueous solution and acetonitrile (3:1, v/v) were used as solvent. The model was validated using 10 standard melamine solutions which were unused to build up the calibration set. Infrared (IR) absorbance peaks specific to almost all chemical groups in melamine molecule were shown in the spectral range between 1,100 and 1,800/cm. Combined partial least squares (PLS)-$2^{nd}$ derivative calibration model coupled with mean centering (MC) mathematical enhancement showed the highest correlation coefficients ($R^2$>0.99). In brief, the FTIR technique can be used for quantitative analysis of melamine in milk samples.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1507-1509
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• 1997

Property of insulation of electric machine is severely affected by process of electrical tree growing. Partial discharges(PD) have been used to determine degradation of insulations. In this paper, PD quantities detected and analyzed are PD magnitudes, repetition rates, phase angle distribution of PD pulses, and wavelet transformation. The wavelet transformation is an extended method of fourier transformation. The fourier transformation is a powerful tool for signal analysis, but it can't include informations for time. However the wavelet transformation analysis can include on the informations of time and frequencies at the same time. This paper discusses correlation between process of electrical tree growing and characteristics of PD in LDPE specimens.

• Korean Journal of Childcare and Education
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• v.14 no.5
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• pp.101-115
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• 2018

Objective: The goals of this research were (1)to examine the relationship among parental conflict, mothers' depression and preschoolers' sleep problems, and (2) to examine the mediating effects of mothers' depression between marital conflict and preschoolers' sleep problems. Methods: The participants were 1,639 mothers with preschoolers taken from the 5th year Korean Children Panel. Date were analyzed using descriptive statistics, partial correlation analysis, and multiple regression analysis. Results: The results were as follows: First, preschoolers' sleep problems were positively related to marital conflicts. Second, preschoolers' sleep problems were positively related to mothers' depression. Third, marital conflict was positively related to mothers' depression. Lastly, mothers' depression fully mediated the relationship between marital conflict and preschoolers' sleep problems. That is, marital conflict had an effect on preschoolers' sleep problem, only through mothers' depression. Conclusion/Implications: Based on the results, intervention programs should be developed to prevent preschoolers' sleep problems such as marital relationship improvement programs and mothers' depression improvement programs.

• Korea journal of population studies
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• v.11 no.2
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• pp.3-10
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• 1988

This study is a replication of Clemente and Sturgis' study conducted among 600 American cities in 1972. The impact of population size, physical density, social density, and age of 56 Korean cities upon the extent of their industrial diversification was analyzed. Hypotheses concerning each independent variable were generated from the theory of the development of the division of labor proposed by Durkheim and subsequently adopted by human ecologists. Zero-order correlation analysis and regression analysis were employed to test the hypotheses. The standardized partial regression coefficients indicated that social density and age of cities exert significant positive impact upon industrial diversification. On the other hand, population size showed a significant negative impact upon industrial diversification. In addition, it was discovered that the combined influence of the independent variables account for 34.6 percent of the variation in industrial diversification. The findings of this study were compared with the results of Clemente and Sturgis' study. Some suggestions for future research are presented and discussed.