• Food Science and Biotechnology
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• v.16 no.1
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• pp.23-28
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• 2007

A linear correlation was found by stepwise multiple regression analysis between the sensory score of barley bran sauce aroma and the absolute gas chromatogram (GC) data transformed with square root. In spite of highly significant relationship between the quantity of the peak and the sensory score, it is difficult to estimate the aroma quality of barley bran sauce samples on the basis of only one peak. Peak 29 (methyl 9,12,15-octadecatrienoate) contributed most to the aroma of barley bran sauce. This was followed by 27 (methyl 9,12-octadecadienoate), 28 (ethyl 9,12-octadecadienoate), 12 (phenyl acetaldehyde), and 9 (methyl furfural) in terms of absolute value. When it was calculated using absolute value transformed by square root, peak 28 (ethyl 9,12-octadecadienoate) made the highest contribution to the aroma of barley bran sauce of among the peaks. It was followed by 31 (9,12-octadecadienoic acid), 27 (methyl 9,12-octadecadienoate), 12 (phenyl acetaldehyde), and 29 (methyl 9,12,15-octadecatrienoate).

• The korean journal of orthodontics
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• v.51 no.6
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• pp.397-406
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• 2021

Objective: The purpose of this study was to evaluate the effects of self-ligating brackets (SBs) and other factors that influence orthodontic treatment outcomes. Methods: This two-armed cohort study included consecutively treated patients in a private practice. The patients were asked to choose between SBs and conventional brackets (CBs); if any patient did not have a preference, he or she was randomly allocated to the CB or SB group. All patients were treated using an identical archwire sequence. Evaluated parameters were as follows: treatment duration, number of bracket failures, poor oral hygiene, poor elastic wear, extraction, use of orthodontic mini-implants (OMI), OMI failure, American Board of Orthodontics (ABO) Discrepancy Index (DI), arch length discrepancy, and ABO Cast-Radiograph Evaluation (CRE) score. Stepwise regression analysis was performed to generate the equation for prediction of the CRE. Results: The final sample comprised 134 patients with an average age of 22.73 years. The average DI, CRE, and treatment duration were 21.81, 14.25, and 28.63 months, respectively. Analysis of covariance showed a significant difference in CRE between the CB and SB groups after adjusting for the effects of confounding variables. Stepwise regression analysis using four variables, namely extraction, SB use, poor elastic wear, and additional appliance use, could explain only 25.2% of the variance in the CRE. Conclusions: Although the CRE was significantly better for CBs than for SBs, the clinical significance of this result seems to be limited. Extraction, SB use, poor elastic wear, and additional appliance use may have significant effects on treatment outcomes.

• Child Health Nursing Research
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• v.28 no.1
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• pp.82-90
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• 2022

Purpose: The aim of this study was to examine the relationships among parenting role sharing, parenting stress, happiness, and parenting behavior of mothers with 6-year-old children. Methods: This study used data from the seventh Panel Study of Korean Children, which began collecting longitudinal data on a sample of newborn households nationwide in 2008 and will continue yearly until 2027. The participants were 1,560 mothers of children aged 6 years. We conducted statistical analyses using descriptive statistics, the t-test, analysis of variance, Pearson correlation coefficients, and stepwise multiple regression. Results: The mean age of the mothers was 36.8±3.7 years. The mothers' perceived parenting role sharing (r=.07, p=.007), parenting stress (r=-.54, p<.001), and happiness (r=.38, p<.001) were significantly correlated with warm parenting behavior. Stepwise multiple regression analysis revealed that parenting stress (β=-.47, p<.001), happiness (β=.15, p<.001), and parenting role sharing (β=.11, p<.001) were significant predictors for warm parenting behavior by mothers. Conclusion: It is essential to reduce mothers' stress and increase their positive emotions (happiness). Fathers should actively share parenting roles in raising children to enhance mothers' warm parenting behavior.

• Communications for Statistical Applications and Methods
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• v.28 no.2
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• pp.189-204
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• 2021

In a regression analysis, a single best model is usually selected among several candidate models. However, it is often useful to combine several candidate models to achieve better performance, especially, in the prediction viewpoint. Model combining methods such as stacking and Bayesian model averaging (BMA) have been suggested from the perspective of averaging candidate models. When the candidate models include a true model, it is expected that BMA generally gives better performance than stacking. On the other hand, when candidate models do not include the true model, it is known that stacking outperforms BMA. Since stacking and BMA approaches have different properties, it is difficult to determine which method is more appropriate under other situations. In particular, it is not easy to find research papers that compare stacking and BMA when regression model assumptions are violated. Therefore, in the paper, we compare the performance among model averaging methods as well as a single best model in the linear regression analysis when standard linear regression assumptions are violated. Simulations were conducted to compare model averaging methods with the linear regression when data include outliers and data do not include them. We also compared them when data include errors from a non-normal distribution. The model averaging methods were applied to the water pollution data, which have a strong multicollinearity among variables. Simulation studies showed that the stacking method tends to give better performance than BMA or standard linear regression analysis (including the stepwise selection method) in the sense of risks (see (3.1)) or prediction error (see (3.2)) when typical linear regression assumptions are violated.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.39-47
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• 2007

The relationships between the cover of herbaceous species and 15 soil chemical properties (organic carbon contents, total N, available P, exchangeable K, Na, Ca and Mg, HCl-extractable Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in nine poorly controlled waste landfill sites in Korea were examined by correlation analysis and multiple regression equations. Species showed different patterns of correlation between their cover values and soil chemical properties. The cover of Ambrosia artemisiifolia var. elatior, Aster subulatus var. sandwicensis and Erechtites hieracifolia were negatively correlated with the contents of Fe, Mn and Ni within landfill soils. Total cover of all species in quadrats was positively correlated with the contents of Cd and negatively correlated with the contents of Mn and Fe from stepwise regression analysis with 15 soil properties. Canonical correspondence analysis demonstrated that the distribution of native and exotic plants on poorly controlled landfills was significantly influenced by the contents of Na and Ca in soils, respectively.

• The Journal of Korean Medicine
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• v.28 no.2 s.70
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• pp.22-33
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• 2007

Uterine myoma is a benign tumor of smooth muscle in the uterine wall. Recently, in Oriental medicine, concerns about uterine myoma patients have increased. We analyzed the medical records for 944 patients, including 257 uterine myoma patients, who visited Dongeui University Oriental Medical Center from May 2001 to June 2006. We investigated the DSOM (Diagnosis System of Oriental Medicine) symptom scores which effect uterine myoma patients using stepwise logistic regression model. Logistic regression analysis indicated as follows: In the control group composed of 558 outpatients, 18 items of DSOM were associated with myoma, 9 positively and 9 negatively, and the results showed that the correct rate was equal to 81.1%, sensitivity 72.8%, and specificity 84.9%. In 129 clinical trials data, 33 items of DSOM were associated with myoma, 18 positively and 15 negatively, and the results showed that the correct rate was equal to 85.8%, sensitivity 84.8%, and specificity 87.6%. In 687 outpatient and clinical trials data, 18 items of DSOM were associated with myoma, 10 positively and 8 negatively, and the results showed that the correct rate was equal to 82.8%, sensitivity 70.8%, and specificity 87.3%.

• Journal of Korean Academy of Nursing
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• v.33 no.8
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• pp.1093-1110
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• 2003

Purpose. The number of elders in institutions has increased as family supporting systems have changed in Korea. The purpose of this study were to understand the life satisfaction among elders in institutions and to identify the factors influencing on life satisfaction. Methods. The instruments used were Yun(1982)'s scale modified Memorial University of Newfoundland Scale for Happiness(MUNSH) in life satisfaction, ADL and IADL in activity level, Self-rating Depression Scale(SDS) in depression and Norbeck Social Support Questionnaire(NSSQ) scale in social support. Also, Perceived health status was measured by Visual Graphic Rating Scale. The subject of this study is 107 cognitively intact and ambulatory elders in 7 institutions in Daegu city and Kyungpook province. The data have been collected from May 1 to June 30, 2001. For the analysis of collected data, frequency analysis, mean, standard deviation, Pearson's correlation and stepwise multiple regression analysis were used for statistical analysis by SPSS win(version 9.0) program. Results. Life satisfaction for the elders in institutions showed negative correlation with SDS, and positive correlation with activity level. The regression form of the stepwise multiple regression analysis to investigate the influencing factors of life satisfaction for the elders in institutions was expressed by y =90.988-0. 733x1-0.188x2-0.069x3-0.565x4 (xl: SDS x2: Social support x3: Activity level x4: Monthly pocket Money) and 57.9% of varience in life satisfaction was explained by the model. Conclusion. The factors influencing on life satisfaction among the elders in institutions were SDS, social support, activity level and monthly pocket money. According to the results of this study, depression, social support and activity level are considered the prime causal factors for life satisfaction.

• Journal of Korean Academy of Nursing
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• v.32 no.6
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• pp.812-822
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• 2002

The Purpose of this study was to identify the relationship among leadership style of nurse managers, job satisfaction, organizational commitment, and turnover intention. Method: The subjects were 468 nurses and 19 head nurses who were working at the 3 general hospitals in seoul. The data were collected from July 6 to September 14, 2001 by the structured questionnaires. For data analysis, descriptive statistics, ANOVA, Pearson correlation coefficient, and stepwise multiple regression with SAS package were used. Result: 1) The score of the nurse managers' transformational leadership perceived by surbodinates' were higher than that of the nurse managers' transactional leadership. Among 5 subdimensions of the leadership styles perceived by surbodinates', the scores of 'charisma' and 'intellectual stimulation' were highest and 'management by exception' were lowest. 2) 'Charisma', 'intellectual stimulation', 'individual consideration' and 'contingent reward' were positively related to all of variables except 'turnover intention'. 'Management by exception' was negatively related to all of variables and was positively related to 'turnover intention'. 3) 'Job satisfaction' was positively related to 'organizational commitment' and 'Job satisfaction', 'organizational commitment' were negatively related to 'turnover intention'. 4) As a result of stepwise multiple regression analysis, the key determinants of 'turnover intention' were 'organizational commitment' and this explained 44.4% of the total variance of it.

• Korean Journal of Adult Nursing
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• v.23 no.1
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• pp.31-39
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• 2011

Purpose: A descriptive study was conducted to examine the relationship of illness perception, self-efficacy, and self-care of patients who were diagnosed pulmonary tuberculosis. Methods: The study was conducted using a convenient sample from two hospitals in Incheon and Seoul. One hundred forty four patients completed a questionnaire which included questions on general characteristics, a Brief Illness Perception Scale, a Self-efficacy Scale and a Self-care Scale. Data were analyzed by using descriptive statistics, t-test, ANOVA, Pearson Moment Correlations and stepwise multiple regression analysis. Results: There was a statistically significant positive correlation between illness perception and self-care (r=.335, p=.000) and between self-efficacy and self-care (r=.687, p=.000). Stepwise multiple regression analysis revealed that among the three variables the most powerful predictor was self-efficacy. Self-efficacy and illness perception were significant factors and accounted for 54.2% of the variance of self care in pulmonary tuberculosis patients. Conclusion: Self-efficacy and illness perception were influencing factors in self care among patients with pulmonary tuberculosis. Hence further interventional researches are needed that consider these two variables.

• Korean Parent-Child Health Journal
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• v.7 no.1
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• pp.38-49
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• 2004

This study is to investigate the main factors influencing prenatal attachment. The research method is on the basis of descriptive correlational study, and data collecting period was from 11 to 29, November, 2003. The objects of this study were 100 pregnant women of two OBGY Hospitals in Masan. Using the SPSS/WIN 10.1 program the data were analyzed by t-test, ANOVA, Pearson correlation coefficient, stepwise multiple regression analysis. The result of this study was as follows : The mean score of prenatal attachment was 2.64, the mean score of physical discomforts, 1.61, the mean score of husband-wife attachment, 3.28, the mean score of psychosocial adjustment of pregnancy, 1.82. The degree of prenatal attachment according to general characteristics was significantly difference according to religion. The degree of prenatal attachment according to obstetrical characteristics was significantly difference according to Lamaze class, Taekyo. Significant correlations of prenatal attachment was found in both psychosocial adjustment of pregnancy, Taekyo, husband-wife attachment, Lamaze class, religion. Stepwise multiple regression analysis showed that 52% of the variance in prenatal attachment was significantly accounted by psychosocial adjustment of pregnancy(34%), Taekyo(6%), husband-wife attachment(5%), Lamaze c1ass(5%), and religion(3%). Further findings of this study support the development of creative strategies to enhance positive attachment relationship for pregnant woman.