• Journal of the Korean Data and Information Science Society
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• v.23 no.5
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• pp.949-959
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• 2012

This article is to find the right size of decision trees that performs better for boosting algorithm. First we defined the tree size D as the depth of a decision tree. Then we compared the performance of boosting algorithm with different tree sizes in the experiment. Although it is an usual practice to set the tree size in boosting algorithm to be small, we figured out that the choice of D has a significant influence on the performance of boosting algorithm. Furthermore, we found out that the tree size D need to be sufficiently large for some dataset. The experiment result shows that there exists an optimal D for each dataset and choosing the right size D is important in improving the performance of boosting. We also tried to find the model for estimating the right size D suitable for boosting algorithm, using variables that can explain the nature of a given dataset. The suggested model reveals that the optimal tree size D for a given dataset can be estimated by the error rate of stump tree, the number of classes, the depth of a single tree, and the gini impurity.

• Journal of Korean Society of Rural Planning
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• v.22 no.4
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• pp.1-11
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• 2016

Public transportation is public service that is contributed to the convenience of the public. However, opportunity for public services in rural areas is weaker than the chance in urban areas. The purpose of this study is to evaluate accessibility of various public facilities using public transportation. To evaluate the accessibility, we calculate the various time from community center to the nearest bus stop, walking time, riding time in bus, and waiting time for transfer. The results of this study ares as follows; (1) Villages occupy 19.8% in rural areas that walking time from community center to the nearest bus stop takes over 10 minutes in integrated Chungju-si; (2) The average speed is 21.9 km/hr estimated to departure and arrival time of bus route; (3) The accessibility time from community center using the average bus speed takes 15.43 minutes to public facilities, 35.15 minutes to emergency center, 8.70 minutes to medical center, 9.70 minutes to elementary school, 16.26 minutes to middle school, and 22.61 minutes high school; (4) The transfer time of public transportation takes 13.46, 21.96, 10.48, 7.78, 11.11, 16.10 minutes to public facilities, emergency center, medical center, elementary school, middle school, and high school, respectively; (4) Traffic accessibility using bus vehicles in the East and South Chungju-si is lower than areas in the West and North Chungju-si. Some villages surrounding public offices (eup-myeon office) which have a high density of population, indicate a high traffic accessibility.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.45-54
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• 2008

Based on the data obtained from field investigation and soil testing to slope hazards occurrence section and non-occurrence section in gneiss area, a prediction technique was developed by the use of a decision tree model, which is one of the statistical analysis methods. The slope hazards data of Seoul and Kyonggi Province, which were induced by heavy rainfall in 1998, were 104 sections in gneiss area. The number of data applied in developing prediction model was 61 sections except a vacant value. Among these data, the number of data occurred slope hazards was 34 sections and the number of data non-occurred slope hazards was 27 sections. The statistical analyses using the decision tree model were applied to chi-square statistics, gini index and entrophy index. As the results of analyses, a slope angle, a degree of saturation and an elevation were selected as the classification standard. The prediction model of decision tree using entrophy index is most likely accurate. The classification standard of the selected prediction model is composed of the slope angle, the degree of saturation and the elevation from the first choice stage. The classification standard values of the slope angle, the degree of saturation and elevation are $17.9^{\circ}$, 52.1% and 320 m, respectively.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.4
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• pp.718-742
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• 2014

The capitalist economic process of glocalization and development of transportation and communication technology have led us to the significance of network city as well as concepts of global city, megacity region, etc. Network city theory pursues development of both individual cities and of the region of those cities through strengthening of mutual connectivity among them with specialized industries. On the basis of network city theory, this paper is to analyze specialized industries of cities and connectivity among them in the Youngnam region in S. Korea. It uses the methods of locational quotient, locational Gini coefficient, and shift-share method to analyze specialized industries of cities, and correspondence analysis, global and local Moran's I to examine connectivity among cities. As results, it can be identified that each city in the Youngnam region has its own specialized industries different from each others, but it seems not easy to grasp the overall extent of connectivity among them, partly because of the limitations of applied analysis methods and partly because of a lack of connectivity among cities themselves.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.6 no.1
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• pp.23-37
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• 2011

This paper is brought to carry out an empirical study whether evolution process of venture firm's scale is following the Gibrat's law; random evolution process, or Pareto law; self-organizing process. The empirical test, as attaching theoretical explanation, of this research utilize the serial data samples of 92 KOSDAQ listed companies from the year of 2005 through 2008. Summarizing the research results are as followed. First, Gini Coefficients representing the density of venture firm's scale has been constantly reduced since the year of 2005 in terms of number of employee, while these index increased during the same time period from the perspective of sales volume. Second, the evolution process of Korea venture firm's scale is following the Power Law related to Pareto Law. In particular, estimated Pareto coefficient, ${\alpha}$, is shown lower than 1 which is significant result. Third, the probability of joining in the top tier group of firm starting from the early stage growing is forecasted into 6.9%, the result which emphasize the starting scale of venture firm play an important role in long term evolution of venture firm.

• Journal of the Korean Geographical Society
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• v.42 no.6
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• pp.914-929
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• 2007

This study analyzes the accessibility patterns for commuting trips in Seoul Metropolitan Area using National Census Data between 1990 and 2000. the results show that the accessibility increased between 1990 and 1995, while it decreased between 1995 and 2000, due to the raised commuting time. Seoul, Kangju, Yeuju, Yangpyoung, Gapyoung show relatively high accessibility. The GINI parameters tell that the regional balance for commuting accessibility were worsen between 1990 and 1995, compared to that between 1995 and 2000. The accessibility patterns for commuting to Seoul were also analyzed and the result shows that the accessibility reduced between 1995 and 2000. Kwachun, Kwangju, Sungnum are found to have very high accessibility to Seoul, which is close to Soeoul with high percentage of incoming commuting trips. These results indicate that even continuous transport infrastructure supplies were not enough to solve the congestion problems for commuting trips in Seoul Metropolitan Area because of the induced traffic and traffic congestion.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.9
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• pp.355-362
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• 2019

In the past, when research and development(R&D) resources were absolutely scarce, the so-called 'choice and concentration' strategy of national R&D projects has been persuasive. Under the current situation where various actors such as GRIs(Government-funded Research Institutes) and universities supported by more abundant R&D resources conduct national R&D projects, this strategy cannot be applied without distinction. In order to see how the strategy has worked, this paper analyzes the concentration of research funds allocated to actors performing national R&D projects. Concentration is measured based on the amount of research funds supported by government from 2002 to 2016 using the Theil index to break down the concentration of individual actors in the overall national R&D project. The results from the Theil index were compared with concentrations using the Gini coefficient, a widely known indicator. As a result, the Theil index could be used to analyze the concentration and sub-components' contribution such as universities and GRIs that make up the entire national R&D system. The results also showed GRIs had the highest concentration, followed by universities, but their concentration has been somewhat reduced compared to 10 years ago. On the other hand, small-sized companies have maintained a certain level, although they are not highly concentrated. In other words, universities and GRIs tend to reduce the gap in the allocation of research funds among institutions, while small-sized companies tend to distribute them evenly.

• 한국노년학
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• v.25 no.2
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• pp.73-93
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• 2005

This study explores the determinants of economic status and well-being among elderly Koreans. Particular emphasis is paid to the role of intergenerational support in these processes because institutional responses to an aging population in Korea are currently inadequate. Path model results indicate that status maintenance variables have significant effects on economic status and well-being as measured by comprehensive income. Further, inequality in comprehensive income - as measured by the Gini and Theil's indices - is substantial and increases in successive age groups. However, market-based and family-based income, two components of comprehensive income, show different patterns. Inequality in market-based income is apparently increasing, while inequality in family-based income is decreasing gradually in successive age groups. With respect to the role of intergenerational support, results indicate that family-income-focused persons possess highly vulnerable sociodemographic characteristics, and that for the socially disadvantaged elderly Koreans, intergenerational support plays a crucial role in the later stages of life. This study also discusses the implications of these findings for the transition from latency to manifestation of intergenerational support in Korea.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.49-61
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• 2024

South Korea faces a declining population and rural areas vanishing due to urbanization. Infrastructure, especially medical facilities, may not be sustainable for a long-term. This may impact vulnerable groups like children, teens, and the elderly, worsened by an aging population and low birth rates. Gangwon-do, notably Chuncheon-si, suffers from rural depopulation and poor healthcare self-sufficiency. In this paper, using 2SFCA(Two-Step Floating Catchment Area), we analyze healthcare access in Chuncheon-si, identifying gaps and vulnerable areas. LISA analysis helps map medical vulnerability, considering patient demand and supply. The Gini coefficient assesses spatial inequality. We propose distributing healthcare services and personnel based on age and region. The aim is to identify locations for additional hospitals catering to the elders, Infants, Children, and Adolescents,considering spatial accessibility.

• Journal of the Economic Geographical Society of Korea
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• v.26 no.4
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• pp.359-374
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• 2023

The main purpose of this paper is to explore the relationship between the transformation of Chinese regional development policy and trends in spatial inequality in mainland China. More specifically, it has attempted to identify the effects of Chinese regional development policies on regional economic inequality by investigating the coefficient of variation and Gini coefficient with GRDP in the province level. Regional inequality in China had increased from 1979 economic reform, but has eased since the 10th Five Year Plan(2001~2005) due to large-scale state investments in the western, central and northeastern regions. However, the analysis is likely to be resulted from the national level. Trends in regional inequality are differentiated in accordance with the eastern, central, northeastern and western regions. For example, regional inequality in the central region has increased, whereas other three regions has decreased since the 10th Five Year Plan. It has played a role in cutting down regional inequality in the national level. In particular, the central region has kept inequality since the 12th Five Year Guideline. It has led to the convergence of the regional economies in the national level. It has stemmed from some limits to greater regional policies in the Central region enforced in the 11th Five Year Guideline(2005~2010).