• Journal of the Korean Geographical Society
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• v.39 no.2
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• pp.212-228
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• 2004

This paper is concerned with an important aspect of regional income convergence, ${\beta}$-convergence, which refers to the negative relationship between initial income levels and income growth rates of regions over a period of time. The common research framework on ${\beta}$-convergence which is based on OLS regression models has two drawbacks. First, it ignores spatially autocorrelated residuals. Second, it does not provide any way of exploring spatial heterogeneity across regions in terms of ${\beta}$-convergence. Given that empirical studies on ${\beta}$-convergence need to be edified by spatial data analysis, this paper aims to: (1) provide a critical review of empirical studies on ${\beta}$-convergence from a spatial perspective; (2) investigate spatio-temporal income dynamics across the U.S. labor market areas for the last 30 years (1969-1999) by fitting spatial regression models and applying bivariate ESDA techniques. The major findings are as follows. First, the hypothesis of ${\beta}$-convergence was only partially evidenced, and the trend substantively varied across sub-periods. Second, a SAR model indicated that ${\beta}$-coefficient for the entire period was not significant at the 99％ confidence level, which may lead to a conclusion that there is no statistical evidence of regional income convergence in the US over the last three decades. Third, the results from bivariate ESDA techniques and a GWR model report that there was a substantive level of spatial heterogeneity in the catch-up process, and suggested possible spatial regimes. It was also observed that the sub-periods showed a substantial level of spatio-temporal heterogeneity in ${\beta}$-convergence: the catch-up scenario in a spatial sense was least pronounced during the 1980s.

• Environmental and Resource Economics Review
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• v.28 no.1
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• pp.1-37
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• 2019

This study investigates the convergence in per capita $CO_2$ emission by income group for an unbalanced panel of 152 countries from 1980 to 2013 using beta and sigma convergence model. Absolute beta and sigma convergence differed by $CO_2$ emission reduction policies in each countries. Conditional beta convergence shows that per capita income has a negative effect on growth in per capita $CO_2$ emission. In particular, better-quality institutions and technology accelerated the negative effect of per capita income on the speed of convergence of per capita $CO_2$ emission in high-income countries. For middle-income countries, the growth of income affected the convergence of $CO_2$ emission per capita, but institutional quality has an insignificant impact. On the other hand, improvements in the level of technology have a mitigating effect on the negative impact of income in middle-income and low-income countries, contributing to the increase in $CO_2$ emission.

• Environmental and Resource Economics Review
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• v.23 no.1
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• pp.67-89
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• 2014

This paper uses patent data of OECD countries in order to investigate if there is converging tendency in renewable energy area. We used the concepts of sigma convergence and beta convergence to measure the convergence. GINI coefficient, HH index are also borrowed from other area of economics. The results show that technology level does not seem to have been converging in this area. Even though the number of patent in relatively less advanced countries has been increased a lot, we could find no evidence that there is the tendency that the gap among the countries have been narrowed. This is quite different from the results of IT industry or other industry since we could find the converging tendency in the data of those industries. Instead, it seems that there is the convergence club among most advance countries in renewable energy area.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.303-306
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• 2001

패턴 인식에서 선형 분류 가능한 경계면을 찾아 패턴을 분류하는 방법 중 가장 기본적인 방법은 퍼셉트론이라고 볼 수 있다. 하지만 선형 분류 불가능한 패턴에 대해서는 유용한 결과를 보여주지 못하였다. 먼저 제안된 퍼지 퍼셉트론은 베타영역 설정에 의해 수렴하지 못하는 특성을 보완하였다. 그러나 패턴의 순수한 전형성을 고려해 주지 못하는 단점이 있다. 이에 Crisp의 선형분류 특성과 퍼지의. 수렴특성을 합성하고자 Possibilistic 퍼셉트론을 제시한다.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.101-105
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• 2000

This study was to investigate the effect of EEG wave type on visual cortex of visual target according to position of fixation point on the Korean. Visual evoked potential system used the BIO-Pag and recorded to 586 computer. The illumination was 500 lux and the visual target was red light dot of 3 cm size. The results of the convergence and divergence as follows: The visual stimulation waves on the visual cortex have about 70% of delta wave, about 10% of beta wave, about 9% of theta wave and about 7% of alpha wave respectively. The convergence state was much more appeared the fast wave on the comparative of the divergence. Therefore, the convergence state was much more producted the beta and alpha wave on the comparative of the divergence. On the other hand, on the convergence and divergence, the histogram amplitude of EEG wave appeared almost the non-Gaussian shape. According to the phase analysis of amplitude of EEG wave almost all type was linear shape.

• Journal of the Korea Convergence Society
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• v.7 no.4
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• pp.217-227
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• 2016

This paper analyzes whether social welfare services converge across the regions. We tested whether local social welfare services converge considering the congestion rate of local social welfare services during the 1985-2013 periods in Korea, using the sixteen higher level local governments panel data. The main findings are as follows. First, the absolute level of local social welfare services converge so that the -convergence exists. Second, the growth rate of local social welfare services increases as the intial level of local social welfare services is lower so that there exists -convergence. The policy implications of our findings are as follows. The local government had better consider the presence of local social welfare services in policy decision making. Also, fundamentally the social welfare policies had better be executed by the central government rather than local governments, since the national minimum welfare must be provided.

• Journal of the Korean Regional Science Association
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• v.35 no.4
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• pp.19-32
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• 2019

Since the 2000s, China has been trying to develop the mid- and western regions and reduce regional disparity between the eastern region and the others by construction of the eight HSR corridors known as 4+4. The high-speed railway is known to have a positive impact on regional economic development by improving accessibility between regions. However, some studies point out that the high-speed railways could worsen regional imbalances. The purpose of this study is to examine the impact of the high-speed railway on regional economic growth and balanced development in China, using the beta-convergence model. In particular, we focused on how the effects of high-speed trains on regional economic development varied depending on the level of development. The analysis was conducted centering on the Shanghai-Chengdu line which is connecting eastern, central and western regions with different levels of development.

• Journal of the Korean Institute of Intelligent Systems
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• v.12 no.1
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• pp.14-18
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• 2002

The perceptron algorithm, which is one of a class of gradient descent techniques, has been widely used in pattern recognition to determine linear decision boundaries. However, it may not give desirable results when pattern sets are nonlinerly separable. A fuzzy version was developed to male up for the weaknesses in the crisp perceptron algorithm. This was achieved by assigning memberships to the pattern sets. However, still another drawback exists in that the pattern memberships do not consider class typicality of the patterns. Therefore, we propose a possibilistic approach to the crisp perceptron algorithm. This algorithm combines the linearly separable property of the crisp version and the convergence property of the fuzzy version. Several examples are given to show the validity of the method.