• The Korean Journal of Applied Statistics
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• v.35 no.2
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• pp.311-325
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• 2022

For count responses, the situation of excess zeros often occurs in various research fields. Zero-inflated model is a common choice for modeling such count data. Bayesian inference for the zero-inflated model has long been recognized as a hard problem because the form of conditional posterior distribution is not in closed form. Recently, however, Pillow and Scott (2012) and Polson et al. (2013) proposed a Pólya-Gamma data-augmentation strategy for logistic and negative binomial models, facilitating Bayesian inference for the zero-inflated model. We apply Bayesian zero-inflated negative binomial regression model to longitudinal pharmaceutical data which have been previously analyzed by Min and Agresti (2005). To facilitate posterior sampling for longitudinal zero-inflated model, we use the Pólya-Gamma data-augmentation strategy.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.51-63
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• 2020

Phonological awareness is a metalinguistic awareness ability of phonology and is known to predict language skills, such as reading and vocabulary skills. The purpose of this study was to investigate the relationship between phonological awareness, phonological processing, and language skills in 4- to 6-years-old typically developing (TD) children and children with language delay (LD). A total of 32 children (TD=18, LD=15) participated in this study. They performed a phonological awareness task consisting of counting, deletion, and discrimination at syllable level. Nonword Repetition, Digit Backward, Receptive & Expressive Vocabulary Test, and Grammaticality Judgment Task were performed to analyze the correlation between phonological awareness, phonological processing, and language ability. A multiple stepwise regression analysis was performed to examine the phonological awareness subtasks that predict language ability. In the TD group, the syllable categorization task significantly predicted the receptive vocabulary and the performance of the Grammaticality Judgment Task. The LD group showed that the syllable counting task significantly predicted the receptive vocabulary, the expressive vocabulary, and the performance of the Grammaticality Judgment Task. The results showed that the phonological awareness performance was significantly different between the two groups. Further, correlation analysis and regression analysis showed different results for each group. The result of the phonological awareness performance predicted the language ability of each group significantly, suggesting the importance of the meta-linguistic awareness ability of phonology.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.6
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• pp.43-51
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• 2013

This study aims to examine the presence of non-stationary relationship between water quality and land use in watersheds. In investigating the relationships between land use and water quality, most previous studies adopted OLS method which is assumed stationarity. However, this approach is difficult to capture the local variation of the relationships. We used 146 sampling data and land cover data of Korean Ministry of Environment to build conventional regressions and GWR models for BOD, TN and TP. Regression model and GWR models of BOD, TN, TP were compared with $R^2$, AICc and Moran's I. The results of comparisons and descriptive statistics of GWR models strongly indicated the presence of Non-Stationarity between water quality and land use.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.643-656
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• 2016

High dimensional data are frequently encountered in various fields where the number of variables is greater than the number of samples. It is usually necessary to select variables to estimate regression coefficients and avoid overfitting in high dimensional data. A penalized regression model simultaneously obtains variable selection and estimation of coefficients which makes them frequently used for high dimensional data. However, the penalized regression model also needs to select the optimal model by choosing a tuning parameter based on the model selection criterion. This study deals with the bias effect of LASSO regression for model selection criteria. We numerically describes the bias effect to the model selection criteria and apply the proposed correction to the identification of biomarkers for lung cancer based on gene expression data.

• Journal of the Korean Data and Information Science Society
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• v.24 no.2
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• pp.267-275
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• 2013

Among data mining techniques, the association rule is the most recently developed technique, and it finds the relevance between two items in a large database. And it is directly applied in the field because it clearly quantifies the relationship between two or more items. When we determine whether an association rule is meaningful, we utilize interestingness measures such as support, confidence, and lift. Interestingness measures are meaningful in that it shows the causes for pruning uninteresting rules statistically or logically. But the criteria of these measures are chosen by experiences, and the number of useful rules is hard to estimate. If too many rules are generated, we cannot effectively extract the useful rules.In this paper, we designed a variety of non-linear regression equations considering all association thresholds between the number of rules and three interestingness measures. And then we diagnosed multi-collinearity and autocorrelation problems, and used analysis of variance results and adjusted coefficients of determination for the best model through numerical experiments.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.705-716
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• 2020

The aim of this article is to examine the relationships between authentic leadership and job satisfaction and to test the moderating effects of co-workers undermining on that relationship. Data were collected from 24th companies in Korea. The sample included 490 employees chosen randomly. Moderated hierarchical regression was used to examine the moderating role of co-workers undermining on the authentic leadership and job satisfaction relationship. The results show that authentic leadership is positively and significantly correlated with job satisfaction. In addition, the results of the hierarchical multiple regression analyses support the moderating effects of perceived employee co-workers undermining with regard to the relationship between authentic leadership and job satisfaction. This study contributes to suggesting the role of co-worker's undermining as a key moderator of their relationship. The theoretical as well as practical implications of the results were discussed with the suggestion for future research.

• Journal of the Korean Society for information Management
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• v.26 no.4
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• pp.169-186
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• 2009

This paper examined what factors affect the immediacy index showing the average number of times an article is cited in the year it is published. Not only Seventy-one immediacy indexes for subject field biology on JCR 2008 edition were gathered, but also many characteristics of scholarly journals that may influence the indexes directly or indirectly were aggregated. Simple correlation coefficient analysis, factor analysis, and regression analysis were performed on the paper. Therefore factors such as physical volume, availability, forthcoming issue, age and language explaining 67.64% of total variance were identified. After regression analysis using these factors as independent variables, the results were statistically significant. The results showed physical volumes, the total pages of publication, have an influence upon immediacy indexes obviously, although it is expected that journal reputations may affect immediacy indexes. Generally open access journals had high immediacy indexes. High ranked journals on immediacy index were apt to be issued frequently, uploaded very often on PMC, and published in major countries including United States and United Kingdom.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.14 no.2
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• pp.1-13
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• 2015

Traffic volume data is basic information that is used in a wide variety of fields. Existing missing traffic volume data imputation method did not take the effect on the rainfall. This research analyzed considering of the rainfall effect in missing traffic volume data imputation method. In order to consider the effect of rainfall, established the following assumption. When missing of traffic volume data generated in rainy days it would be more accurate to use only the traffic volume data of the past rainy days. To confirm this assumption, compared for accuracy of imputed results at three kinds of imputation method(Unconditional Mean, Auto Regression, Expectation-Maximization Algorithm). The analysis results, the case on consideration of the rainfall effect was more low error occurred.

• The Journal of the Korea Contents Association
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• v.12 no.2
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• pp.461-471
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• 2012

The purpose of this paper is to visualize the housing market dynamics with ESDA (Exploratory Spatial Data Analysis) using MATLAB toolbox, in terms of the modeling housing market dynamics in the Busan Metropolitan City. The data are used the real housing price transaction records in Busan from the first quarter of 2006 to the second quarter of 2009. Hedonic house price model, which is not reflecting spatial autocorrelation, has been a powerful tool in understanding housing market dynamics in urban housing economics. This study considers spatial autocorrelation in order to improve the traditional hedonic model which is based on OLS(Ordinary Least Squares) method. The study is, also, investigated the comparison in terms of $R^2$, Sigma Square(${\sigma}^2$), Likelihood(LR) among spatial econometrics models such as SAR(Spatial Autoregressive Models), SEM(Spatial Errors Models), and SAC(General Spatial Models). The major finding of the study is that the SAR, SEM, SAC are far better than the traditional OLS model, considering the various indicators. In addition, the SEM and the SAC are superior to the SAR.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.673-680
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• 2013

The purpose of this study is the Influence of Sailing Yacht Experiences Participants of Flow on Satisfaction and Self-esteem relates to the impact on leisure industry, the popularity of korean culture and yacht basis for the realization is to provide. To achieve this study, Busan, Ulsan, Gyeongnam area residents to target marine leisure and marine leisure experiences Academy experienced subjects participated in a total population of 428 people selected for the survey was conducted, data processing method frequency analysis, reliability analysis, validity analysis, a simple regression analysis, multiple regression analysis was used. Than as a result of research methods and data analysis through the conclusions are as follows. First, sailing yacht experience the flow degree of the participants to influence satisfaction were static. Second, the flow degree of the participants experienced sailing yacht self-esteem(general factors, family factors, work factors, social factors) was found to affect the static. Third, sailing yacht experience satisfaction self-esteem of the participants(general factor, family factors, work factors, social factors) was found to affect the static.