• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.179-190
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• 2009

In the financial industry, the decision tree algorithm has been widely used for classification analysis. In this case one of the major difficulties is that there are so many explanatory variables to be considered for modeling. So we do need to find effective method for reducing the number of explanatory variables under condition that the modeling results are not affected seriously. In this research, we try to compare the various variable reducing methods and to find the best method based on the modeling accuracy for the tree algorithm. We applied the methods on the pension insurance of a insurance company for getting empirical results. As a result, we found that selecting variables by using the sensitivity analysis of neural network method is the most effective method for reducing the number of variables while keeping the accuracy.

• The Journal of Fisheries Business Administration
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• v.48 no.2
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• pp.67-82
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• 2017

The study intends to examine the effects of the fishing license system on fisheries resources in order to reduce the adverse effects of recreational fishing, such as fishery resource reduction and environmental pollution. In doing so, the research question of the study is to determine what factors influence anglers' willingness to support fishing licenses. Based on the extended theory of planned behavior, we further included explanatory variables such as recreation specialization and motivations besides anglers' attitudes, norms and self-efficacy towards the environment and proposed six research hypotheses. The data were collected through on-site and online surveys in Gwangju and Cheonnam province and a total of 337 effective questionnaires were collected for data analysis. Three different binary logit models were employed with the dependent variable of anglers'willingness to support fishing licenses to assess the effects of explanatory variables. Study results show that social norms, the level of recreation specialization, motivation factors related to environmental experiences positively affected anglers'willingness to support fishing licenses. However, anglers'consumptive orientation attitudes such as catching big fish, motivation factors related to activity general experience preferences and previous fishing experience had negative effects on the dependent variables. Study results indicate that public outreach and education programs are essential to successfully introduce the fishing license system. Managerial and policy-related implications are further discussed to make recreational fishing a more environment-friendly recreational activity. This study investigated the effects of diverse variables derived from anglers' social-psychological characteristics on their support for fishing licenses and suggest diverse policy-related and managerial implications.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.4
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• pp.390-402
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• 2009

This study aimed to examine the general characteristics of individual workers, psychosocial working environment, and ergonomic risk factors which affect the status of musculoskeletal disorders. Self-report was carried out for musculoskeletal symptoms and ergonomic risks in working environment in 856 production workers in 16 small to medium sized manufacturing companies. Musculoskeletal symptoms were examined with a standardized questionnaire, and ergonomic risks were evaluated with a qualitative self-administered instrument for the tasks related to musculoskeletal disorders. Major findings were as follows: 1) Complaint rate for musculoskeletal symptoms was higher in female, aged, married workers with longer working hours, less leisure/hobby activity, longer household working hours and history of disease or accident. 2) Complaint rate for musculoskeletal symptoms was significantly higher in workers with dissatisfaction, difficult tasks, and no self-control at work. 3) Complaint rate for musculoskeletal symptoms was significantly higher in workers involved in tasks with major ergonomic risk factors, and handling heavy equipment. 4) Explanatory power increased the model with the musculoskeletal symptoms as dependent variable and demographic variables, psychosocial working environment and ergonomic risk factors included, and total explanatory power of 18.6% revealed the significant effect. Based on the results, we can conclude that musculoskeletal symptoms in manufacturing workers are associated with individual demographic characteristics, psychosocial working environment and ergonomic risk factors.

• Journal of the Korean Data and Information Science Society
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• v.28 no.6
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• pp.1471-1479
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• 2017

The variability of trade price index of apartment influences on the various aspect, especially economics, social phenomenon, industry, and culture of the country. In this article, the autoregressive error (ARE) model has been considered for analyzing the monthly trading price index of apartment data. About 16 years of the monthly data have been used from September 2001 to May 2017. In the ARE model, six macroeconomic variables are used as the explanatory variables for the rade price index of apartment. The six explanatory variables are mortgage rate, oil import price index, consumer price index, KOSPI stock index, GDP, and GNI. The result has shown that trading price index of apartment explained about 76% by the mortgage rate, and KOSPI stock index.

• Environmental and Resource Economics Review
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• v.16 no.2
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• pp.239-273
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• 2007

Bunker-C is sold at the different price in the market for international bunkering and for export, though the quality of bunker-c is not much different in two markets. The price difference in two markets tends to increase since 2002 in Korea. This study shows that there is a possibility for a structural change in the price difference in two markets in Korea around June, 2002. In the search for possible explanations for this structural change, empirical analyses found that the price difference in Singapore, which had not have any explanatory power before June, 2002, has explained the price difference in Korea after July, 2002. Other explanatory variable for the price difference was the growth rate of crude oil price in the previous period. The empirical results suggest that the price difference in bunkering market and export market might be explained by the price discrimination which is adopted as a competitive strategy by oil companies in competing with Singapore.

• Korean Journal of Human Ecology
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• v.16 no.5
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• pp.1041-1050
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• 2007

The purpose of this study was to investigate the variables which had effects on deit behavior of male and female high school students. The proposed variables are their body-related variables(body satisfaction, weight control experience, the degree of diet interest, and obesity) and self-esteem. The sample group used for the study consisted of 359 high school students(male=168, female=191). Measurement scales used for the study were those of body-related variables, self esteem and eating disorder behavior, and data analysis was performed using $X^2$, t-test, Pearson's correlation, regression analysis. The results are as follows. First, there is a significant difference between male and female high school students regarding their obesity perceived by themselves, body satisfaction, the degree of diet interest, weight control experience, and deit behavior. Second, In male students, diet behavior shows a positive correlation with the degree of diet interest, weight control experience, and body satisfaction, but shows a negative correlation with body satisfaction. In female students, diet behavior is positively correlated with the degree of diet interest, weight control experience, and obesity, but negatively correlated with body satisfaction and self-esteem. Third, in male students, the variables that showed a influence on diet behavior as an eating disorder are weight control experience, body satisfaction and obesity, in that the explanatory power of the variables is 51.7% with the highest mark on obesity. In female, the variables that showed a influence on diet behavior as an eating disorder are the degree of diet interest, weight control experience, body satisfaction and obesity, in that the explanatory power of the variables is 66.0%.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.356-366
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• 2019

Various TBM performance prediction models have been developed and most of them were considered penetration rate only. Despite the fact that some models have suggested equations and charts for estimating the utilization factor, but there are a few studies to estimate the TBM utilization factor. Utilization factor is affected by the type of TBM machine, operation, maintenance of machine, geological conditions, contractor experience and other factors. In this study, more than 100 case studies are analyzed to determine the relationship between the utilization factor and RMR, geological conditions, TBM types, tunnel length, and TBM diameter. Simple and multiple linear regression analysis are performed to develop predictive models for the utilization factor. The predictive model with explanatory variables of geological conditions, TBM types, tunnel length, and TBM diameter does not give a good correlation. The predictive models with explanatory variable of RMR give higher values of the coefficient of determination.

• Mood & Emotion
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• v.16 no.3
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• pp.169-177
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• 2018

Objectives : Despite the lack of domestic research, eating alone has been reported to be related to depression. We investigated correlation between eating alone, and depression, among women age 65 and older. Methods : Among women registered in the Korea National Health and Nutrition Examination Survey data, 1,119 elderly in 2014, and 1,189 in 2016, were analyzed. Eating alone and the degree of depression were assessed, using a questionnaire and the Patient Health Questionnaire-9 respectively. The relationship between eating alone and depression, was analyzed using multilevel logistic regression. Results : In 2014 data, eating alone had significant effect on depression, as the explanatory power is increased to 30.4% in a 'three meals eating alone a day' group (${\beta}=0.128$, p<0.05), when the eating alone parameter is added to demographic factors and health characteristics. In 2016, exploitation of 'the frequency of eating alone' variable led to increment of explanatory power to 22.3%, that was not statistically significant. Conclusion : The result of this study suggests that eating alone among women age 65 and older, was a risk factor of depression in 2014, and is becoming a new life pattern as a social and cultural phenomenon in 2016.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.161-165
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• 2022

The purpose of this study was to improve children's positive perceptions of the future by examining the relationship between parental attachment, parental involvement in learning, and children's perceptions of the future, and by identifying the specific influence of each variable on children's perceptions of the future. Frequency analysis and descriptive statistical analysis were performed on data from the 12th year of the Korean Children's Panel (2019), and Pearson's moment correlation coefficient was calculated for correlation analysis between variables. Multiple regression analysis was performed to examine the explanatory power of parental attachment to children's perception of the future and parental participation in learning. The research results are as follows. First, the correlations among all the latent variables of parental attachment, parental participation in learning, and children's future perception showed significant correlations. Second, the explanatory power of children's perception of the future was found in the order of 'mother' trust, 'family'-based participation, 'father' trust, and 'mother' communication. These results suggested that parental trust and warm, warm participation in home-based learning were important variables in children's positive perception of the future.

• Journal of Korea Trade
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• v.27 no.2
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• pp.47-60
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• 2023

Purpose - This paper assesses the trade potential and efficiency of Korea and China in the aquatic products trade. Trade efficiency and potential are the main factors that affect the growth of a country's trade. In this study, a time-varying stochastic frontier trade gravity model was constructed to analyze the trade potential and efficiency between Korea and China. By integrating the results of trade theory and empirical analysis, measures and suggestions were proposed to encourage the release of trade potential of fish exports between Korea and China. Design/methodology - In this paper, GDP per capita instead of economic size was chosen as an explanatory variable, and population size and relative distance were selected as explanatory variables to measure trade potential. For trade non-efficiency terms, regional organizations, political factors, and economic factors were mainly considered, and variables such as free trade agreements, political stability, regulatory quality, government efficiency, currency freedom, investment freedom, financial freedom, and trade freedom were selected. Panel data for South Korea and 14 aquatic products trading partners (including China) from 2002 to 2020 were used in the empirical analysis. Findings - In the past 19 years, South Korea's export trade potential of aquatic products to China has never been lower than 70%. It was above 90% from 2006 to 2018, and has been at a high level for a long time. This shows that China's aquatic product market has large potential for development. Originality/value - This study examines the effectiveness and potential of South Korea's exports of aquatic items to China in a methodical and comprehensive empirical manner. The evaluation of the export trade potential of South Korea's aquatic goods to China is more precise when the effects of regional organization, political, and economic variables are taken into account in the trade non-efficiency term of the stochastic frontier gravity model. At the same time, we propose to increase the scale of South Korea's aquatic products trade from the perspective of China's demand. This issue of trade studies is underexplored both empirically and in theory, although the issue has long been important to Korean and world trade.