• Journal of Soil and Groundwater Environment
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• v.16 no.4
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• pp.10-22
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• 2011

Human health risk assessment for petroleum, oil and lubricant (POL) contaminated sites is challenging as total petroleum hydrocarbon (TPH) is not a single compound but rather a mixture of numerous substances. To address this concern, several TPH fractionation approaches have been proposed and used as an effective management tool for the POL-contaminated sites in many countries. In Korea, there are also recognized needs to establish a reliable and cost-effective human health risk assessment strategy based on the TPH fractionation method. In order to satisfy the social and institutional demand, this study suggested that the comprehensive risk assessment strategy based on a newly modified TPH fractionation method with 10 fractions, the Korean Standard Test Method (KSTM)-based analytical protocol and a stepwise risk assessment framework should be introduced into the domestic contaminated land management system. Under the proposed strategy, POL-contaminated sites can be effectively managed in terms of human health protection, and remedial cost and time can be determined reasonably. In addition, more researches required to increase our understanding of environmental risks and improve the domestic management system were proposed.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1993-2005
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• 2019

Thermophilic anaerobic digestion (TAD) is characterized by higher biogas production rates as a result of assumedly faster microbial metabolic conversion rates compared to mesophilic AD. It was hypothesized that the thermophilic microbiome with its lower diversity than the mesophilic one is more susceptible to disturbances introduced by alterations in the operating factors, as an example, the supply of nitrogen-rich feedstock such as poultry manure (PM). Laboratory scaled TAD experiments using cattle slurry and increasing amounts of PM were carried out to investigate the (in-) stability of the process performance caused by the accumulation of ammonium and ammonia with special emphasis on the microbial community structure and its dynamic variation. The results revealed that the moderate PM addition, i.e., 25% (vol/vol based on volatile substances) PM, resulted in a reorganization of the microbial community structure which was still working sufficiently. With 50% PM application, the microbial community was further stepwise re-organized and was able to compensate for the high cytotoxic ammonia contents only for a short time resulting in consequent process disturbance and final process failure. This study demonstrated the ability of the acclimated thermophilic microbial community to tolerate a certain amount of nitrogen-rich substrate.

• Women's Health Nursing
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• v.22 no.4
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• pp.233-240
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• 2016

Purpose: The purpose of this study was to investigate factors which effect clinical nurses' exhaustion. Methods: This research was conducted targeting 140 clinical nurses. Data were collected from 18 September to 30 September 2015. Data were analyzed using the program SPSS/WIN 18.0. Descriptive statistics, t-test, ANOVA, Pearson correlation coefficient, and Stepwise multiple regression analysis were used. Results: Burnout was significantly different by age (F=7.99, p=.001), marital status (t=8.69, p=.004), department area (F=7.65, p<.001), frequency of night work in a month (F=7.65, p=<.001), and clinical career (F=3.68, p=.028). There was positive correlations between menstrual attitudes of participants and premenstrual syndrome (r=34, p<.001), menstrual attitudes and stress (r=.40, p<.001), and menstrual attitudes and burnout (r=.16, p=.031). There were positive correlations between premenstrual syndrome and stress (r=.46, p<.001), between premenstrual syndrome and burnout (r=.35, p<.001), and between stress and burnout (r=.36, p<.001). Factors influencing burnout were premenstrual syndrome (${\beta}=.335$) and age (${\beta}=.216$), with an explanatory power of 18.0%. Conclusion: There is a need to develop and apply program for reducing clinical nurses' pre-menstrual syndrome. In addition, policies are needed to allow for menstruation leave, thereby making it legal.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.3
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• pp.179-190
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• 1992

This study was carried out to characterize sources of atmospheric total suspended particulates (TSP) in urban and sub--urban areas of metropolitan taegu. The sources were tentatively identified by a multivariate technique, i.e. principal component analysis (PCA), and the source contributions to the atmospheric concentrations of TSP were further estimated by stepwise multiple regression analysis. A total of 5 sources was identified in the urban area of Taegu (soil dust resuspension, fuel combustion, secondary aerosol, traffic related aerosol, and refuge burning), while 4 sources were found to be significant in the sub--urban area as following: fuel combustion/secondary aerosol, soil dust resuspension, traffic related aerosol, and wood/agricultural burning. The largest contributor to the atmospheric TSP appeared to be the soil dust resuspension in both areas. The source apportionment of the extractable organic matter (EOM) was also carried out for the Taegu data. The EOM was determined with respect to the solvent polarity, i.e. cyclohexane (non-polar), dichloromethane (semi--polar), and acetone (polar). In addition, the source profiles for the TSP in Taegu area were estimated using a PCA-based algorithm, and the validity was evaluated tentatively by comparing the data in the literature.

• The Korean Journal of Applied Statistics
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• v.18 no.2
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• pp.435-443
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• 2005

Coefficients of determination in logistic regression analysis are defined as various statistics, and their values are relatively smaller than those for linear regression model. These coefficients of determination are not generally used to evaluate and diagnose logistic regression model. Liao and McGee (2003) proposed two adjusted coefficients of determination which are robust at the addition of inappropriate predictors and the variation of sample size. In this work, these adjusted coefficients of determination are applied to variable selection method for logistic regression model and compared with results of other methods such as the forward selection, backward elimination, stepwise selection, and AIC statistic.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.253-262
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• 1981

The AgI/ PV${\cdot}$THF membrane electrode could be used as an indicator electrode in the potentiometric titration of single halide and mixture halide solutions with the standard solution of silver nitrate. The errors in the stepwise titrations of mixture halide solutions were considerably large, but by addition of flocculating agent, such as $NaNO_3$ or $Ba(NO_3)_2$, in the sample solution, the errors were greatly reduced. Also, the effects of gelatin, filter paper and temperature on the titration errors were examined.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.4
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• pp.453-462
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• 2012

Purpose: The purpose of this study was to examine the impact of job satisfaction and organizational commitment on patient safety management activities of nurses. Methods: A cross-sectional design was adopted. The sample included 307 nurses working in three tertiary university hospitals. Data were collected during November and December, 2012, with a response rate of 93%. A 40-item patient safety management activities scale was used to measure patient safety activities. Job satisfaction and organizational commitment were also measured with established instruments and included general characteristics. Data were analyzed with PASW 18.0 program. Results: The mean score for patient safety management activities was 3.98 out of 5. Stepwise multiple linear regression indicated that organizational commitment (${\beta}$=.20, p<.001) and job satisfaction (${\beta}$=.18, p=.013) respectively predicted patient safety management activities. Especially, the addition of organizational commitment as the strongest predictor of patient safety management activities increased the associated explained variance ($R^2$ change=.11, p<.001). Conclusion: It is important for managers to create an organizational climate that promotes the organizational commitment and job satisfaction of nurses. Future studies are encouraged to replicate the findings and also to better understand patient safety management activities and personal emotional stability.

• Child Health Nursing Research
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• v.26 no.4
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• pp.402-410
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• 2020

Purpose: This study aimed to determine the level of health-related quality of life (HRQoL) of children and adolescents who received hematopoietic stem cell transplantation (HSCT) and to examine factors influencing HRQoL. Methods: This cross-sectional descriptive study involved 85 participants aged 10 to 19 years who received treatment from 3 months to 5 years after HSCT. Symptom experiences, stress and coping, self-esteem, social support, and HRQoL were measured. Descriptive analysis, the independent t-test, one-way analysis of variance, Pearson correlation analysis, and stepwise multiple regression were used for data analysis. Results: The mean HRQoL score was 72.26 points out of 100. HRQoL showed statistically significant correlations with symptom experiences, stress, self-esteem, social support, satisfaction with peer relationships, and perceived attentiveness of the medical team. The most influential predictors of HRQoL were symptom experiences (β=-.51, p<.001) and satisfaction with peer relationships (β=.32, p<.001). Conclusion: The experiences of different symptoms by children and adolescents who receive HSCT must be considered. In addition, nursing interventions, such as self-help meetings with peer groups, should be provided to improve their HRQoL.

• Research in Community and Public Health Nursing
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• v.21 no.3
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• pp.341-350
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• 2010

Purpose: The purpose of this study was to contribute to enhancing elementary school health teachers professional job performance by analyzing their job identity and job stress. Methods: The participants were 138 elementary school health teachers registered at the Busan Metropolitan City Office of Education, and the survey was conducted from the 22nd to 23rd of July, 2010. The collected data were analyzed by percentile, t-test, ANOVA, Pearson's correlation coefficient, and stepwise multiple regression using the SPSS/WIN 17.0 program. Results: The average percentiles of job identity and job stress were 70.6 and 64.0 respectively. Among the sub-factors of job identity, autonomy was highest as 73.5, and among the sub-factors of job stress, job demand was highest as 73.9. There were significant differences in the degree of job identity and job stress according to education status, the number of classes, job satisfaction, enthusiasm for work, and the image of nursing teachers expressed in a word. The regression model explained 21.2% of the variance of job identity. job stress explained 32.0% of the variance. Conclusion: It is important to develop various comprehensive programs for improving job identity and managing job stress. In addition, it is necessary to provide support systems including persons, promotion and rewards to school health teachers.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.11-12
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• 2010

PSC girder with holed web have several benefits. Most of all placing tendon anchorage in the holes can make prestressing forces be loaded stepwise. In addition it can reduce the self-weight of the beams and increase the span length of beams. And holed web might minimize the interference of view. In this study, a 50-meter long full scale multilevel post-tensioned PSC girder was fabricated and modal test was carried out. In order to obtain precise frequency response, vibration exciter was placed at the middle of the girder and excited with several frequencies. Natural frequency and damping ratio were evaluated from FFT and PSD using the obtained frequency response and compared with numerical analysis result.