• Journal of the Korean Statistical Society
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• v.32 no.4
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• pp.425-448
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• 2003

Meta-analysis refers to quantitative methods for combining results from independent studies in order to draw overall conclusions. We consider hierarchical models including selection models under a skewed heavy tailed error distribution proposed originally by Chen et al. (1999) and Branco and Dey (2001). These rich classes of models combine the information of independent studies, allowing investigation of variability both between and within studies, and incorporate weight function. Here, the testing for the skewness parameter is discussed. The score test statistic for such a test can be shown to be expressed as the posterior expectations. Also, we consider the detail computational scheme under skewed normal and skewed Student-t distribution using MCMC method. Finally, we introduce one example from Johnson (1993)'s real data and apply our proposed methodology. We investigate sensitivity of our results under different skewed errors and under different prior distributions.

• The Korean Journal of Applied Statistics
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• v.32 no.1
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• pp.99-109
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• 2019

We compared the confidence intervals of estimators using various bootstrap methods for a Random Coefficient Autoregressive(RCA) model. We consider a Quasi score estimator and M-Quasi score estimator using Huber, Tukey, Andrew and Hempel functions as bounded functions, that do not have required assumption of distribution. A standard bootstrap method, percentile bootstrap method, studentized bootstrap method and hybrid bootstrap method were proposed for the estimations, respectively. In a simulation study, we compared the asymptotic confidence intervals of the Quasi score and M-Quasi score estimator with the bootstrap confidence intervals using the four bootstrap methods when the underlying distribution of the error term of the RCA model follows the normal distribution, the contaminated normal distribution and the double exponential distribution, respectively.

• Communications for Statistical Applications and Methods
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• v.13 no.2
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• pp.359-368
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• 2006

In this paper we derived the asymptotic relative efficiency, ARE(ms, rs), of our new score function with respect to the McKean and Sievers scores for the asymmetric error distributions which often occur in practice. We thoroughly explored the asymptotic relative efficiency, ARE(ms, rs), of our score function that provides much improvement over the McKean and Sievers scores for all values of r and s under asymmetric distributions.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.14-23
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• 1995

Cyclosporin A is a powerful immunosuppressive agent commonly used for patients receiving organ transplants. Like phenytoin and the calcium channel blockers, the drug is associated with gingival overgrowth. The purpose of this study was to compare the correlation with gingival overgrowth score and clinical indices(i.e, : plaque index, papillary bleeding index, probing depth) and correlation with gingival overgrowth score and microorganism distribution in use of phase contrast microscope. After renal tranplant, taking cyclosporin A 40 patients participating in this investigation. Post - transplatation cyclosporin medication period was average $17.53{\pm}15.75$ months. In previous study reported that gingival overgrowth is an adverse side - effects seen in about 25-81% of patient taking cyclosporin A. The results were as follows : 1. Gingival overgrowth prevalence in taking cyclosporin A patients was 77.5%. Prevalence rate of region was anterior region(26 teeth, 55.3%), molar region(14 teeth, 29.8%), premolar region(7 teeth, 14.8%) in turns. Gingival overgrowth score by Angelopoulos & Goaz method was molar region($1.56{\pm}0.81$), anterior region($1.52{\pm}0.75$), premolar region($1.14{\pm}0.90$) in turns. 2. Medication period was not correlation with gingival overgrowth score. 3. Clinical indices and gingival overgrowth score were as follows. 1) Plaque index and gingival overgrowth score was significantly correlated(p

• Journal of Distribution Science
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• v.16 no.5
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• pp.31-43
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• 2018

Purpose - We examine how a Korean retail firm's social responsibility is related to its financial performances. The traditional view of corporation expects a negative relationship, while the stakeholder theory expects a positive one. Research design, data, and methodology - We adopt the ESG score, published by Korean Corporate Governance Service to measure the level of socially responsible activity for the Korean retail firms. The ordinary least square method is adopted to investigate this relationship. The publicly traded retail firms are examined from 2011 to 2016. Results - We find that the total ESG score is negatively related to ROE but shows no statistically significant relationship with ROA and Tobin's Q value. However, a firm's environmental score is negatively related with both of ROE and ROA. Its social score is no conclusive relationship with the performance measures. The governance score is negatively related to the value of Tobin's Q. Conclusions - This paper generally supports the traditional view of corporate theory, especially in terms of ROE. This evidence is not well aligned with the existing study for Korean corporations generally documenting positive relationships. We find almost no empirical evidence supporting the stakeholder theory of corporation in the Korean retail industry.

• Journal of Distribution Science
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• v.17 no.7
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• pp.55-63
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• 2019

Purpose - This paper examines the value relevance of socially responsible activities in the Korean retail firms. Recent studies predict positive relationships between socially responsible activities and the value of corporation. Research design, data, and methodology - We use the environmental score, social score, governance score and the sum of these three scores to represent a fim's effectiveness of socially responsible activities. These scores are published by the Korean Corporate Governance Service. This paper adopts a share price valuation model to evaluate the effect of socially responsible activities on a firm's share price, which controls for the book value of assets and current earnings. The ordinary least square method is employed to examine the relationship. The sample of Korea retail firms is examined from 2011 to 2016. We also conduct sub-sample analysis based on the categorization of chaebol affiliates and non-chaebol affiliates. Results - The entire sample analysis finds neither negatively nor positively significant relationship between socially responsible activities and the value of a corporation. In contrast, our examinations find a significantly positive valuation effect of social score within non-chaebol retail firms. Conclusions - The results weakly support the positive valuation effect of socially responsible activities. The results are consistent with recent studies that highlight heterogeneous effects of socially responsible activities on corporate policies and valuation.

• Journal of the Korean Dietetic Association
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• v.16 no.2
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• pp.83-99
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• 2010

The purposes of this study were to analyze the quality attributes and customer satisfaction in school foodservice by distribution place and to suggest an improvement plan. The survey was distributed to different respondents (students, parents, and faculty) at different types of schools (elementary school, middle school, and high school) on September 2008 in 16 cities and provinces. The statistics were analyzed using descriptive analysis, t-test, and ANOVA by SPSS 12.0. All foodservice quality attributes were significant different by school type and the students in elementary schools had higher scores than students in middle and high school. A comparison of scores by school type and distribution place demonstrated that elementary schools had a higher score for quality attributes and in middle and high school dining halls had a higher score for quality attributes. The overall customer satisfaction with school foodservice was higher for dining halls than classrooms for all respondents (students, parents, and faculty). For students, the overall customer satisfaction score was 69.1 for schools using dining halls and 66.4 for schools using classrooms. The overall customer satisfaction for classrooms was higher in elementary school but, this score for middle and high school was higher for dining halls. Therefore, students prefer dining halls to classrooms. Especially, as the students grow, they have an increased preference for dining halls.

• Journal of Korean Public Health Nursing
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• v.2 no.2
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• pp.81-98
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• 1988

The purpose of this study was to fine out the general physical status of the neonates, and to identify the risk factors of the mothers and the neonates which were significantly related to the neonatal diseases during hospitalization. The data were obtained from clinical records of 1098 neonates born in Seoul Red cross Hospital between January 1st of 1984 and December 31th of 1986. The results of this study were summarized as follows: 1. General characteristics of the maternal group. 1) The average of maternal age was 26.6 years, the $91.7\%$ of the mothers de liveried at the age of 20-34 years old. 2) The distribution of the types of delivey were as follows : spontaneous delivery $39.9\%$, cesarean section $32.4\%$, vaccum extraction $25.7\%$, and breech delivery$2.0\%$. 3) The $40.3\%$ of the total de liveried mother had experienced abortion. 4) The $42.3\%$ of the total deliveried mother had one or more obstetric risk factors. 2. General characteristics of the neonatal group. 1) In the distribution of sex, male was $49.4\%$, female $50.6\%$. 2) The average of birth weights was 3,020gm. The distribution of birth weight were as follows; nomal weight $85.5\%$, low birth weight $12.7\%$ and high birth weight $2.5\%$. 3) The average of gestational age was 39.2 weeks. The distribution of gestational age were as follows; full term $77.4\%$, preterm $13.7\%$, and postterm $8.9\%$. 4) The average of Apgar Score was 9.0 at one minute and 9.6 at five minutes. 5) The $5.7\%$ of the neonates had one or more neonatal risk symptoms and signs at birth. 3. Apgar Score by the maternal and neonatal factors. In Apgar Score at one minute, normal group was higher than that of abnormal group. Apgar Score at five minutes was slightly higher than that at one minute. 4. The distribution of the maternal risk factors and the neonatal risk factors. 1) The total numbers of the maternal risk factors were 1376. The distribution of the maternal risk factors were as follows: obstetric factor $33.7\%$, abortion $32.2\%$, breech and cesarean section delivery $27.5\%$ and maternal age under 19 years and over 35 years $6.6\%$. 2) The total numbers of the neonatal risk factors were 517. The distribution of the neonatal risk factors were as follows: gestational age under 37 weeks and over 42 weeks $48.0\%$, birth weight under 2500gm and over 4000gm $12.2\%$, Apgar score under 4 at one munute $6.4\%$ and Apgar score at five munutes $2.7\%$. 3) The total numbers of the obstetric risk factors were 661. The types of the obstetric risk factors were meconium stained amniotic fluid $22.0\%$, premature rupture of membrane $17.5\%$. absence prenatal care $14.1\%$, unmarried pregnancy $10.3\%$, placenta problem $9.0\%$, toxemia $8.0\%$. 4) The total numbers of the neonatal risk symptoms and signs at birth were 83. The types of the neonatal risk symptoms and signs were respiratory distress $65.1\%$, neonatal apnea $14.4\%$, convulsion $13.3%$, meconium aspiration syndrome $4.8\%$, cyanosis $2.4\%$. 5. The relationship between the maternal risk factors and the neonatal risk factors. 1) Maternal age under 19 years or over 35 years was significantly related to Apgar Score under 4 at 5 minutes. 2) Breech delivery or cesarean section was significantly related to neonatal risk factor at birth such as birth weight, gestational age, Apgar Score at one minute and at five minutes. and neonatal risk symptoms and signs. 3) Obstetric risk factors were significantly related to the neonatal risk factors at birth. 4) Abortion was not related to the neonatal risk factors. 6. The relationship between neonatal diseases during hosptalization and the maternal or the neonatal risk factors. 1) The total numbers of neonatal diseases during hospitalization were 281. The distribution of neonatal diseases were as follows: birth trauma $38.1\%$, infectious disease $31.3\%$, hematologic disease $21.4\%$, respiratory disease $6.0\%$, neurologic disease $2.5\%$. cardiovascular disease $0.7\%$. 3) Most maternal risk factors except abortion were significantly related to neonatal diseases. 4) Most neonatal risk factors at birth were significantly related to neonatal diseases.

• Food Science and Preservation
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• v.30 no.4
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• pp.573-588
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• 2023

The purpose of this study was to monitor changes in the quality of ginseng and predict its shelf-life. As the storage period of ginseng increased, some quality indicators, such as water-soluble pectin (WSP), CDTA-soluble pectin (CSP), cellulose, weight loss, and microbial growth increased, while others (Na₂CO₃-soluble pectin/NSP, hemicellulose, starch, and firmness) decreased. Principal component analysis (PCA) was performed using the quality attribute data and the principal component 1 (PC1) scores extracted from the PCA results were applied to the multivariate analysis. The reaction rate at different temperatures and the temperature dependence of the reaction rate were determined using kinetic and Arrhenius models, respectively. Among the kinetic models, zeroth-order models with cellulose and a PC1 score provided an adequate fit for reaction rate estimation. Hence, the prediction model was constructed by applying the cellulose and PC1 scores to the zeroth-order kinetic and Arrhenius models. The prediction model with PC1 score showed higher R² values (0.877-0.919) than those of cellulose (0.797-0.863), indicating that multivariate analysis using PC1 score is more accurate for the shelf-life prediction of ginseng. The predicted shelf-life using the multivariate accelerated shelf-life test at 5, 20, and 35℃ was 40, 16, and 7 days, respectively.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.1
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• pp.10-16
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• 2015

In this study, we suggest a method to predict probability distribution of a new customer's degree of loyalty using C-CRF that reflects the RFM score and similarity to the neighbors of the customer. An RFM score prediction model is introduced to construct the first feature function of C-CRF. Integrating demographical similarity, purchasing characteristic similarity and purchase history similarity, we make a unified similarity variable to configure the second feature function of C-CRF. Then parameters of each feature function are estimated and we train our C-CRF model by training data set and suggest a probabilistic distribution to estimate a new customer's degree of loyalty. An example is provided to illustrate our model.