• Toxicological Research
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• v.32 no.4
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• pp.337-343
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• 2016

We determined the toxicity of mixtures of ethyl acetate (EA), isopropyl alcohol (IPA), methyl ethyl ketone (MEK), toluene (TOL) and xylene (XYL) with half-maximal effective concentration ($EC_{50}$) values obtained using human hepatocytes cells. According to these data, quantitative property-activity relationships (QPAR) models were successfully proposed to predict the toxicity of mixtures by multiple linear regressions (MLR). The leave-one-out cross validation method was used to find the best subsets of descriptors in the learning methods. Significant differences in physico-chemical properties such as boiling point (BP), specific gravity (SG), Reid vapor pressure (rVP) and flash point (FP) were observed between the single substances and the mixtures. The $EC_{50}$ of the mixture of EA and IPA was significantly lower than that of contained TOL and XYL. The mixture toxicity was related to the mixing ratio of MEK, TOL and XYL (MLR equation $EC_{50}=3.3081-2.5018{\times}TOL-3.2595{\times}XYL-12.6596{\times}MEK{\times}XYL$), as well as to BP, SG, VP and FP (MLR equation $EC_{50}=1.3424+6.2250{\times}FP-7.1198{\times}SG{\times}FP-0.03013{\times}rVP{\times}FP$). These results suggest that QPAR-based models could accurately predict the toxicity of polar and nonpolar mixtures used in rotogravure printing industries.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.169-182
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• 2017

The purpose of this study is to empirically examine a behavior improvement of unethical information sharing through the ethics program in organization. An unethical behavior of information sharing on organization members is to be get to private interests through divulgence of company's confidential information. An unethical information-sharing of individual is the opportunist and selfish behavior for an expansion of social capital and shows a negative ripple effect in organization. When conducting the research methods, the analysis order performs the cluster, discriminant, t-test and multiple regressions. According to the study, There are differences the behavior of unethical information sharing between opportunist and non-opportunist. The opportunist member for unethical behavior improvement required the program operation both value and compliance oriented program. Non-opportunist member required only the value-oriented program. The upcoming research needs to explore both ethics program's frequency and action of a punished person.

• Journal of Korean Biological Nursing Science
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• v.19 no.1
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• pp.48-54
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• 2017

Purpose: This study was done to identify the influence of severity of drinking problem, circadian rhythm and sleep quality in patients with alcohol use. Methods: A descriptive study design was utilized. Data were collected using self-report questionnaires from 139 patients with alcohol use disorder who were admitted to a psychiatric hospital in D city, Korea. The questionnaires included Alcohol Use Disorders Identification Test (AUDIT), Composite Scale of Morningness (CMS), Pittsburgh Sleep Quality Index (PSQI), and Korea sleep scale A. Data were analyzed using descriptive statistics, Pearson's correlation coefficients, and multiple regressions using the SPSS 20.0 program. Results: There was significant correlations among severity of problem drinking, circadian rhythm, sleep quality and sleep disorder. The significant factors influencing sleep disorder were severity of problem drinking(${\beta}=.12$, p= .042), circadian rhythm(${\beta}=-.14$, p= .039) and sleep quality(${\beta}=.63$, p= < .001). This model explained 56% of variance in sleep disorder(F = 57.34, p= < .001). Conclusion: The results of this study suggest that the development of sleep intervention programs for alcohol use disorder patients needs to consider severity of alcohol use, circadian rhythm and sleep quality, and sleep assessment and intervention are needed the early stage of the treatment and recovery process.

• Korean Journal of Childcare and Education
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• v.7 no.3
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• pp.125-141
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• 2011

This study investigates the mediation effects of trait anxiety in the relationships between reports by middle school adolescents in regards to self-differentiation and parents' marital conflicts. The participants were 252 middle school adolescents attended middle schools in Daegu or Gyeongbuk Province. The collected data were analyzed by Pearson's correlation, single and hierarchical multiple regressions, using SPSS 19.0. The results are as follows. (1) Parents' marital conflicts and trait anxiety were negatively associated with self-differentiation of middle school adolescents. (2) Trait anxiety was positively associated with parents' marital conflicts. (3) Trait anxiety exerted indirect effects on self-differentiation mediated by parents' marital conflicts.

• Korean Journal of Health Education and Promotion
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• v.27 no.1
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• pp.81-89
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• 2010

Objectives: To investigate the relationship between experience of hunger in childhood or adolescence and diabetes mellitus in old age. Methods: Stratified national samples of 421 men and 554 women aged 60-89 in South Korea were analyzed. Diabetes diagnosed by a doctor was used as the dependent variable. Experience of hunger in childhood was assessed with the question, "In your childhood, have you ever gone hungry with skipping a meal?" and "In your childhood, have you ever eaten porridge or some bran cake as main dish instead of rice because of lack of food?" Odds ratios (ORs) and 95% confidence interval (CI) were calculated by multiple logistic regressions. Results: ORs of diabetes by experience of hunger in childhood were 1.64(95% CI 0.95-2.83) for men and 1.58(95% CI 1.01-2.47) for women. Significant association of experience of hunger in childhood with prevalence of diabetes persisted in men after adjustment for adulthood and old age socioeconomic position indicators and other risk factors(OR 1.88(95% CI 1.04-3.41)). The effect of experience of hunger in 10-19 years was more prominent than that in less than 10 years in both gender. Conclusion: Experience of hunger in childhood or adolescence may increase the risk of diabetes in Korean elders.

• Journal of the Korean Home Economics Association
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• v.43 no.8 s.210
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• pp.55-68
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• 2005

The purpose of this study is to examine the effects of negative life events on mental health and to explore possible main and moderating effects of spousal support on mental health with a focus on gender differences. The data for this study were taken from a nationwide random sample of 1,504 married men and women ranging in age from 30 to 59 through structured questionnaires. The data were analyzed using the SPSS WIN program which was used to calculate frequency, mean, 1-test, multiple regressions. The main results were as follows: First, by examining mental health of Korean men and women, women were more likely than men to experience higher levels of depression. Second, there was no gender difference in the sum of experience of negative life events, therefore the date of this study did not support the differential exposure hypothesis. In addition, men perceived more support from their spouses than women. Third, results show that especially the event concerning with job/financial problems has negative impacts on mental health of both men and women, and vulnerability to undesirable life events was not found. Fourth, spousal support is associated with better mental health regardless of gender, and it reduces the harmful effects of life events concerning with job/financial area for both men and women. Also, spousal support reduces the magnitude of the harmful effects of life events concerning with health of men. This study focused on the impact of negative life events and the couple process. It was possible to explore the strength of social support provided from spouse of most importance to the individuals. These results affirm the importance of supportive relationships between couples as a buffer, mitigating harmful effects of negative life events on mental health.

• Advances in aircraft and spacecraft science
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• v.6 no.6
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• pp.529-550
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• 2019

The effect of multiple process parameters on a set of continuous response variables is, especially in experimental designs, difficult and intricate to determine. Due to the complexity in aeroacoustic and vibroacoustic studies, the often-performed simple one-factor-at-a-time method turns out to be the least effective approach. In contrast, the statistical Design of Experiments is a technique used with the objective to maximize the obtained information while keeping the experimental effort at a minimum. The presented work aims at giving insights on Design of Experiments applied to aeroacoustic and vibroacoustic problems while comparing different experimental designs and approximation models. For this purpose, an experimental rig of a ducted low-pressure fan is developed that allows gathering data of both, aerodynamic and aeroacoustic nature while analysing three independent process parameters. The experimental designs used to sample the design space are a Central Composite design and a Box-Behnken design, both used to model a response surface regression, and Latin Hypercube sampling to model an Artificial Neural network. The results indicate that Latin Hypercube sampling extracts information that is more diverse and, in combination with an Artificial Neural network, outperforms the quadratic response surface regressions. It is shown that the Latin Hypercube sampling, initially developed for computer-aided experiments, can also be used as an experimental design. To further increase the benefit of the presented approach, spectral information of every experimental test point is extracted and Artificial Neural networks are chosen for modelling the spectral information since they show to be the most universal approximators.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1627-1631
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• 2015

Background: Stage at diagnosis is one of the most important prognostic factors of breast cancer survival. Because in the breast cancer case this may vary with socioeconomic characteristics, this study was performed to recognize the relationship between demographic and socioeconomic factors with stage at diagnosis in Iran. Materials and Methods: This cross-sectional, descriptive study conducted on 526 patients suffering from breast cancer and registered in Cancer Research Center of Shahid Beheshti University of Medical Sciences from 2008 to 2013. A reliable and valid questionnaire about family levels of socioeconomic status filled in by interviewing the patients via phone. For analyzing the data, Multinomial logistic regression, Kendal tau-b correlation coefficient and Contingency Coefficient tests were executed by SPSS22. Economic status, educational attainment of patient and household head and/or a combination of these were considered as parameters for socioeconomic status. First, the relationship between stage at diagnosis and demographic and socioeconomic status was assessed in univariate analysis then these relationships assessed in two different models of multinomial logistic regression. Results: The mean age of the patients was 48.3 (SD=11.4). According to the results of this study, there were significant relationships between stage at diagnosis of breast cancer with patient education (p=0.011), living place (p=0.044) and combined socioeconomic status (p=0.024). These relationships persisted in multiple multinomial logistic regressions. Other variables, however, had no significant correlation. Conclusions: Patient education, combined socioeconomic status and living place are important variables in stage at diagnosis of breast cancer in Iranian women. Interventions have to be applied with the aim of raising women's accessibility to diagnostic and medical facilities and also awareness in order to reducing delay in referring. In addition, covering breast cancer screening services by insurance is recommended.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.366-375
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• 2016

This study aims to investigate the impact of total, native-born, and foreign-born employment rates on the increases of GDP and per capita GDP for 24 OECD countries out of 34 countries depending on data availability. The panel data analysis is formed by a fixed-effects model which allows dummy variable in it to permit the intercept term to vary over time-series and cross-sectional units. Empirical evidences obtained by simple and multiple panel regressions reveal that the contribution to increasing of GDP by foreign-born employment is obviously lower than the one by native-born employment. And, native-born labor is substituted by foreign-born labor. It also has to be mentioned that the labor is playing a key role in increasing in national income. And, therefore, labor-related policy should be concerned on decreasing in labor productivity and segmentation of labor market resulted from inflow of foreign labor. It means that labor-related policy has to take care of not only the magnitude, but also the quality of foreign-born labor.

• The Journal of the Korea Contents Association
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• v.16 no.3
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• pp.732-741
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• 2016

This research examines the relationships and effects among ROKAF officer's job satisfaction and psychological well-being and their self-leadership. Multiple regressions were conducted using 211 data. Results are as follows. First, Job satisfaction, psychological well-being and self-leadership were significantly positively correlated with each other. Second, as for the effects of subordinate factors among job satisfaction and psychological well-being on the subordinate factors of self-leadership, personal growth and controling environment of psychological well-being and administration of job satisfaction influenced self-expectation of self-leadership. For the self-reward of self-leadership, personal growth, meaning of life and autonomy of psychological well-being and relationship and reward system of job satisfaction influenced it. Finally, as for the effects of subordinate factors among job satisfaction and psychological well-being on self-leadership, administration and relationship of job satisfaction and personal growth, meaning of life and autonomy of psychological well-being influenced it. Finally implications and limitations of this research are discussed.