• Journal of Digital Convergence
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• v.16 no.3
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• pp.157-167
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• 2018

The shortage of research in Vietnam port evolvement is uncontroversial although a huge amount of investment is observed to upgrade both quantity and quality. This study examines the port system performance, in the context of spatially concentration ratio, in Southern Vietnam for the period 2007-2016, by using prevailing indicators for spatially concentration assessment including concentration ratios (CR), the Herfindahl-Hirschman index (HHI), the Gini coefficient, the Lorenz curve and shift-share analysis (SSA), a trend of deconcentration is described in Southern Vietnam port system, since the traditional ports to new deep-water ports. Also, driving forces of this shifting would be discussed in detail. Implications from this study would enable not only port administrators, port operators but also shipping lines, cargo owners, logistics service providers to comprehensively understand the growth of the port system in Southern Vietnam.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.405-413
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• 2015

The purpose of this study is to measure the level of competition in the degree of Regional Public Hospital that can provide a basis for establishing an effective management strategy and analysis of the financial performance. Investigation period of the Regional Public Hospital HHI(Herfindahl-Hirschman Index) over three years from 2010, which was unknown until 2012, index and management performance evaluation criteria, a total of 31 were selected as Regional Public Hospital surveyed. In the conclusions, it showed that the most concentrated market with high financial performance, a significant correlation between the degree of local competition and financial indicators showed. The Regional Public Hospital for trends according to the degree of competitive local medical market and therefore is required to establish policies and practices to ensure competitiveness and public interest in the region. The Regional Public Hospital in order to preempt the lead for the competitiveness of other institutions will be considered in the strategy, such as improving medical services and capital investment.

• Journal of Aerospace System Engineering
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• v.16 no.2
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• pp.1-12
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• 2022

The purpose of this study was to investigate the supply and demand structure of the domestic space industry through analysis of industrial concentration index, by sector and dependence on revenue by customer type. As a result of industrial concentration analysis, in the case of space application, a supply monopoly or oligopoly structure was revealed in fields such as satellite broadcasting, space insurance, and satellite navigation. In the field of space equipment manufacturing, referred to as the traditional space industry, a supply monopoly structure appeared only in the field of launch pads and test facilities. As a result of analyzing the dependence on revenue by customer type, the dependence on the demand in the space application field is diversified among foreign countries, private institutions, and others. However, in the case of space equipment manufacturing, it is highly dependent on the demand of public institutions, and it seems that there is a monopsony structure.

• Journal of Korea Port Economic Association
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• v.32 no.1
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• pp.135-149
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• 2016

This study analyzes the concentration ratios (CR) and the shift effect in the system of Korean container ports that concern the export and import of container cargos, especially from/to 5 overseas origin/destination (O/D) regions, using the Hirshmann-Herfindahl Index (HHI) and the Shift-Share Method. The results shows that the CR has decreased during the last 20 years, from 0.86 to 0.44, mainly because cargos from/to the Far-East/South-East Asian regions have become more dispersed to several domestic container ports, especially from the Port of Busan. This study also indicates that there has been little change in the CR for all cargos, like the value of -0.3%, in the last 5 years. However the change in CRs for the cargos from/to the North America and Europe is positive, with the value of 7.6% and 6.6%, respectively. It can be inferred that the future development of medium- and small-sized container ports in Korea is not very likely. The study also suggests that the CR and the shift effect of the Korean container ports for the cargos by the domestic O/D regions should be analyzed in the future to suggest policy implications in great detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.401-408
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• 2019

This study was conducted to analyze the industrial concentration of the districts, cities and counties among clinics, dental clinics, and Oriental clinics. For this purpose, the sales from 1996 to 2015 in five-year intervals were analyzed by the Heifindal-Hirschmann index (HHI). The results of this study showed that the competition index represented by the HHI tended to intensify as a whole. Especially in the county area, HHI tended to be in comparison with other regions, but decreased with statistically significance. On average, the HHI was higher in the county than in the district and city areas. In the case of the clinic, the HHI of the county area tended to decrease. In the case of the dental clinic, the HHI tended to decrease in the city and county, while in the Oriental clinic the HHI tended to decrease in the district, city and county. Overall, monopolies were present in the county, but competition strengthened over time. In the case of clinics, competition is intensifying in country. area. In the case of dental clinics, competition in the city and country areas has not yet reached saturation. In the case of Oriental clinics, competition in all regions has not yet been saturated, and competition in the distinct market has been most intense.

• Journal of Korea Port Economic Association
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• v.26 no.2
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• pp.139-149
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• 2010

This paper analyses the relative efficiency of 13 container terminals based on the data for the period 2003-8 to offer a fresh perspective. There has been abundant empirical research undertaken on the technical efficiency of Busan and Gwangyang port. Most studies have focused on the use of parametric and non-parametric techniques to analyse overall technical efficiency. Here, the framework assumes that terminals use two input to produce one output; the former includes container yard and container crane and the latter container volume. Jarque-Bera indicates that three variables are not normally distributed and the positive skewness shows that all the variables have long right tails. This means there are many small-scaled container terminals. This paper also employs heteroscedastic Tobit model to show the effect of the explanatory variables on the container terminal efficiencies. The Tobit model shows that both container yard and container cranes have positive effect on the container terminal efficiency, but container yard has a higher impact on the efficiency than the container crane.

• Journal of Korea Port Economic Association
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• v.30 no.3
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• pp.39-58
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• 2014

Korea and China have maintained sea routes between two nations through the shipping conference which was established in May 1993. Due to this effort, the market of Korea-China car ferry on Yellow sea makes growth year by year. The car ferry business has shown fierce competition because it has huge impacts on regional and national level economy. In this respect, the aim of this research is to analyze the structural analysis for ports of Korea-China car ferry using Shift Effect(SE) method. As a results, passengers and cargo volumes of Incheon port continuously transfer to Pyeontaek and Gunsan port. Moreover, absolute growth rate of Incheon port do not reach the potential growth rate. The competitiveness power of Incheon port has lower position compared to Pyeontaek and Gunsan port. The cargo volumes of ports located on western coast of Korea have increased recently, however, passengers and cargo volumes of Incheon port have shown lower increasing rate compared to average of Korean western coast ports. For Incheon port, high value added cargoes which give large profit on port side, have to be attracted. Moreover, Incheon port has to become a specialized port.

• International Area Studies Review
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• v.13 no.2
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• pp.226-253
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• 2009

The study analyzes the trend of regional economic development disparity in China, sets up research period from 1952 to 2008, and uses the after-modified regional GDP data by the first national economic census in 2004. The results as follow. Firstly, the Coefficient of variation(CV) with after-modified GDP data lower than the pre-modified data. Secondly, generally speaking, after-reform and open period's disparity lower than pre-reform and open period. In particular, the regional development disparity increased slowly after 1990, not rapidly. Third, the new cycle of the inverse-U type is appeared from 2002. Fourth, compared with Herfindhal-Hirschman index(HHI) and Theil Entrophy index(TEI), the lower level regions more affect to reduce the disparity in 1980s, and it also affect to reduce the disparity after 2000. Fifth, the convergence hypothesis test finds that the regional economic development disparity has been converged in 1978-2008. Sixth, the inverse-U type hypothesis not has statistical significance, from 1952 to 2008, but it has statistical significance from 1991 to 2008. This result same as the CV and the convergence test.

• Journal of Intelligence and Information Systems
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• v.26 no.1
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• pp.23-45
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• 2020

Big data is creating in a wide variety of fields such as medical care, manufacturing, logistics, sales site, SNS, and the dataset characteristics are also diverse. In order to secure the competitiveness of companies, it is necessary to improve decision-making capacity using a classification algorithm. However, most of them do not have sufficient knowledge on what kind of classification algorithm is appropriate for a specific problem area. In other words, determining which classification algorithm is appropriate depending on the characteristics of the dataset was has been a task that required expertise and effort. This is because the relationship between the characteristics of datasets (called meta-features) and the performance of classification algorithms has not been fully understood. Moreover, there has been little research on meta-features reflecting the characteristics of multi-class. Therefore, the purpose of this study is to empirically analyze whether meta-features of multi-class datasets have a significant effect on the performance of classification algorithms. In this study, meta-features of multi-class datasets were identified into two factors, (the data structure and the data complexity,) and seven representative meta-features were selected. Among those, we included the Herfindahl-Hirschman Index (HHI), originally a market concentration measurement index, in the meta-features to replace IR(Imbalanced Ratio). Also, we developed a new index called Reverse ReLU Silhouette Score into the meta-feature set. Among the UCI Machine Learning Repository data, six representative datasets (Balance Scale, PageBlocks, Car Evaluation, User Knowledge-Modeling, Wine Quality(red), Contraceptive Method Choice) were selected. The class of each dataset was classified by using the classification algorithms (KNN, Logistic Regression, Nave Bayes, Random Forest, and SVM) selected in the study. For each dataset, we applied 10-fold cross validation method. 10% to 100% oversampling method is applied for each fold and meta-features of the dataset is measured. The meta-features selected are HHI, Number of Classes, Number of Features, Entropy, Reverse ReLU Silhouette Score, Nonlinearity of Linear Classifier, Hub Score. F1-score was selected as the dependent variable. As a result, the results of this study showed that the six meta-features including Reverse ReLU Silhouette Score and HHI proposed in this study have a significant effect on the classification performance. (1) The meta-features HHI proposed in this study was significant in the classification performance. (2) The number of variables has a significant effect on the classification performance, unlike the number of classes, but it has a positive effect. (3) The number of classes has a negative effect on the performance of classification. (4) Entropy has a significant effect on the performance of classification. (5) The Reverse ReLU Silhouette Score also significantly affects the classification performance at a significant level of 0.01. (6) The nonlinearity of linear classifiers has a significant negative effect on classification performance. In addition, the results of the analysis by the classification algorithms were also consistent. In the regression analysis by classification algorithm, Naïve Bayes algorithm does not have a significant effect on the number of variables unlike other classification algorithms. This study has two theoretical contributions: (1) two new meta-features (HHI, Reverse ReLU Silhouette score) was proved to be significant. (2) The effects of data characteristics on the performance of classification were investigated using meta-features. The practical contribution points (1) can be utilized in the development of classification algorithm recommendation system according to the characteristics of datasets. (2) Many data scientists are often testing by adjusting the parameters of the algorithm to find the optimal algorithm for the situation because the characteristics of the data are different. In this process, excessive waste of resources occurs due to hardware, cost, time, and manpower. This study is expected to be useful for machine learning, data mining researchers, practitioners, and machine learning-based system developers. The composition of this study consists of introduction, related research, research model, experiment, conclusion and discussion.

• Health Policy and Management
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• v.34 no.1
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• pp.38-47
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• 2024

Background: Korea's population of children and adolescents has decreased by 2.88 million over the past decade and is expected to decline further due to the unprecedented low birth rate. In the fee-for-service compensation system, the decline in the pediatric population relates directly to the profit decrease in the pediatric clinics. This study analyzed whether the worsening profits of pediatric clinics impacted their closure. Methods: We built annual data for pediatric and other department clinics (internal medicine, otolaryngology, and family medicine) using the status of medical institute and health insurance claims data from 2012 to 2022. Then, we analyzed whether institutional variables such as annual profit and regional variables (Herfindahl-Hirschman index, the number of clinics per 100,000, etc.) affected the closure of clinics. The methods used in this study are descriptive statistics and chi-square analysis. Odds ratios for each variable were estimated by generalized estimating equations (GEE). Results: The closure rate of pediatric clinics was 2.66%-7.04% in 2012-2022, which was consistently higher than those of internal medicine, otolaryngology, and family medicine clinics. The profit gap per institution between the pediatric and the other clinics grew from 126 million won in 2012 to 245 million won in 2019. In the GEE analysis, profit decrease compared to the previous year with lower profit was the main factor that increased the closure of pediatric and other department clinics. After adjusting profit-related variables, the decrease in the pediatric population itself did not relate to the closure of pediatric clinics. The number of pediatric clinics or monopolies also did not affect the closure of pediatric clinics. Conclusion: The worsening profit is the crucial factor for the closure of pediatric clinics, while the pediatric population is decreasing. For this reason, it is necessary to actively seek ways to maintain a stable treatment system for children and adolescents.