• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.4
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• pp.765-773
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• 2009

Currently Telematics traffic information services have been various because we can collect real-time traffic information through Intelligent Transport System. In this paper, we proposed and implemented a short-term traffic information prediction model for giving to guarantee the traffic information with high quality in the near future. A Short-term prediction model is for forecasting traffic flows of each segment in the near future. Our prediction model gives an average speed on the each segment from 5 minutes later to 60 minutes later. We designed a Bayesian network for each segment with some casual nodes which makes an impact to the road situation in the future and found out its joint probability density function on the supposition of GMM(Gaussian Mixture Model) using EM(Expectation Maximization) algorithm with training real-time traffic data. To validate the precision of our prediction model we had conducted various experiments with real-time traffic data and computed RMSE(Root Mean Square Error) between a real speed and its prediction speed. As the result, our model gave 4.5, 4.8, 5.2 as an average value of RMSE about 10, 30, 60 minutes later, respectively.

• International Area Studies Review
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• v.22 no.3
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• pp.175-200
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• 2018

Since the 1990s rising intangible asset has become one of the main driving forces of investment stagnation and jobless growth in advanced income countries. We investigate how does the impact of firms' profitability on employment growth depends on the intangibility and whether the relationship between profitability and tangibility has complementarity. With data on Korean firms over the period 1988~2017 we investigate the effects of intangibility and profitability on employment growth based on the econometric approach of system GMM. The empirical results are as follows. (1) the profit rate has gradually led to lower employment growth, while it had positive effect on employment before the period of financial crisis. The estimated values and signs of profit rate coefficients varies from traditional industries to high/medium tech. industries. (2) the effect of increasing asset intangibility ratio on employment growth is negative and statistically significant. (3) the coefficients of interaction term of (profit rate ${\times}$ intangibility ratio) have significant negative values. It means employment effect of profit rate are becoming higher(lower) as intangibility ratio is at the lower(higher) level; profits rate and intangibility are not complement with each other. The results imply that to boost employment industrial policy which has the capacity to coordinate business intangibility is preferred to expansionary demand policy.

• 한국사회정책
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• v.24 no.4
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• pp.185-222
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• 2017

The purpose of this study is to investigate the effect of labor market policy on fiscal soundness of welfare state. The analysis was carried out using cross-sectional panel data regression analysis, stepwise mediating effect analysis and system GMM designed by Baron and Kenny(1986) based on the data from 1985 to 2015 for 20 OECD countries. In setting up the analysis model, this study considers the interaction effect between active and passive labor market policies as well as the time sequence of the outcomes which have been overlooked in the previous studies. The result shows that labor market policies have significant impacts on the fiscal condition of welfare states, which is measured as the levels of national debt in this study. Especially the expenditure on active labor market programs has a positive effect on improving the fiscal soundness of welfare states by promoting the employment rate. In contrast, passive labor market programs expenditure is negatively associated with employment rate growth and it exacerbates the burden of national debt in the short-term. However, when active labor market programs and passive labor market programs are combined, the negative impacts by passive pabor market policies on the fiscal soundness of welfare states are off-set. Therefore this study addresses that although the expansion of the labor market policies can be inimical to the fiscal soundness of welfare states in the short-term, in the long run, they can have effective roles in securing and promoting the fiscal soundness of the welfare states by promoting the employment rate.