• Korean journal of communication and information
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• v.34
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• pp.7-33
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• 2006

This paper try to explain the phenomenon on convergence of broadcasting and telecommunication by the law of the tendential fall in the rate of profit. With the progressive decline in the variable capital in relation to the constant capital in the sphere of the telecommunication, this tendency leads to a rising organic composition of the total capital, and the direct result of this is that the rate of surplus-value, with the level of exploitation of labour remaining the same or even rising, is expressed in a steadily falling general rate of profit. The reason to apply this law is to inquire into the true state of the phenomenon on convergence of broadcasting and telecommunication showed like the disorderly development.

• Journal of the Korea Society of Computer and Information
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• v.25 no.12
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• pp.35-44
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• 2020

In this study, we analyze how stock trend determination affects trend prediction accuracy. In stock markets, successful investment requires accurate stock price trend prediction. Therefore, a volume of research has been conducted to improve the trend prediction accuracy. For example, information extracted from SNS (social networking service) and news articles by text mining algorithms is used to enhance the prediction accuracy. Moreover, various machine learning algorithms have been utilized. However, stock trend determination has not been properly analyzed, and conventionally used methods have been employed repeatedly. For this reason, we formulate the trend determination as a moving average-based procedure and analyze its impact on stock trend prediction accuracy. The analysis reveals that trend determination makes prediction accuracy vary as much as 47% and that prediction accuracy is proportional to and inversely proportional to reference window size and target window size, respectively.

• Journal of Korean Society of Forest Science
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• v.36 no.1
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• pp.33-37
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• 1977

The secular trends and seasonal variation of the prices of imported lauan sawtimber, domestic red pine logs and sawtimber have been analyzed to find out the features and origins of price fluctuation in Korea for the period of 1961~1971. The results may be summarized as follows: 1. The relative prices of red pine logs were raised by 1.23 percent per year, and those of red pine and lauan sawtimber were decreased by 0.10 and 0.93 percent, respectively through the period. As a whole, there is a tendency in the country that timber prices were gradually decreased by lowing timber demand through savings in consumption and exploitation of alternative materials, with the increased supply through continuous log import. 2. There is also a tendency that the seasonal variation reduced in the last 15 years. In the period of 1961~1968, the seasonal price indices were peaked in spring and autumn, but thereafter peaked in spring and dropped down until winter. 3. In secular and seasonal variations of timber prices, the trend of sawtimber prices was dependent upon that of log prices but the fluctuation was larger in log prices.

• KDI Journal of Economic Policy
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• v.31 no.2
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• pp.235-266
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• 2009

This paper investigates changes in the extent of exchange rate pass-through to export price in Korea. First, empirical results show that export prices have become less responsive to the exchange rate since the financial crisis in 1997. The decline of exchange rate pass-through to export prices suggests that Korean exporters are more likely to use profit margins to absorb part of the impact of exchange rate changes, consistent with pricing to market phenomenon. Second, this paper finds asymmetries in the response of export prices to exchange rate changes. In the post-crisis period. appreciations are more likely to be offset by markup adjustment than depreciations. Third, this paper documents that a significant portion of the decline of exchange rate pass-through is a result of both increased volatility of exchange rate and increased competition with China in the world market.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.383-391
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• 2017

This study examines the relationship between sentiment of speculators and price movements in the futures markets of WTI crude oil, copper, and wheat during the period 2003~2014 using Granger causality tests. The results indicate that speculative positions overall has no predictive power for returns in each futures market. Rather, returns seem to have effects on speculators' sentiment especially during periods of both economic expansion and recovery. During a recession, meanwhile, changes of speculators' sentiment index in the WTI crude oil and copper markets provide predictive power for returns in a positive direction, suggesting that speculators' pessimistic sentiment aggravates declines in commodity prices. Since the effects of speculative positions on market prices are ambiguous, tight regulations on speculative trading are not advisable. In a bearish market, however, regulatory bodies should consider raising speculative position limits because large speculative short positions and (or) liquidation of index traders' long positions may lead steep price declines.

• Information Systems Review
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• v.24 no.4
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• pp.41-54
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• 2022

Despite the recent rapid advancement of science and technology, we have been experiencing the decline in productivity since the 2000s. This study aims to investigate the decline at both industry and firm levels, by looking at the emergence and growth of large firms such as Amazon, Alphabet, and Apple and M&A trends. Following the results of previous studies, our results show that productivity at industry level has decreased since the 2000s. Particularly, in the period after 2011, the deterioration of allocative efficiency due to the large firms and the decline in the growth rate of surviving firms in the industry with low ratio of large firms contributed to the productivity decline. On the other hand, our analysis at firm level demonstrates that the productivity of firms that acquired IT firms improved over the entire period. While M&As have a positive impact on productivity, M&As with a demand-side motive such as market penetration and expansion of channels have a relatively larger impact than the ones for production or operation efficiency. Our results also suggest that the higher the proportion of large firms in a specific industry, the lower the productivity of individual firms in the same industry. Overall, given that the industry's structural changes for digital transformation tends to strengthen the growth of large firms, our findings have significant implications by empirically identifying the relationships of the emergence of large firms, the acquisition of IT/Non-IT firms, and motivations for M&As to firm/industry productivity.

• Journal of the Korean Regional Science Association
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• v.34 no.1
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• pp.3-17
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• 2018

This paper empirically investigates time-varying regression parameter of hedonic price model for Seoul office rental market in distinct periods of a market cycle. Office rental index is constructed and the index indicates that the global financial crisis differentiates the analysis period into decline stage and recovery stage. Pre-crisis period is classified into decline stage and post-crisis is classified into recovery stage. Structural break-point test suggests structural change of hedonic model of rent determinants occurred in 2008. Evidence indicates that individual regression parameters of hedonic price model for decline stage are significantly different from those for recovery stage. Changes in the regression parameters of land price, distance to metro, building size, building age, and conversion rate are consistent. In recovery stage, the effect of locational advantage on office rent decreases whereas the effect of building characteristics on the rent increases.

• Journal of Labour Economics
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• v.41 no.2
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• pp.1-29
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• 2018

The paper reviews the trend of youth employment in Korea in recent years and examines whether the change in labor demand through declining business dynamism is one of the causes. The analysis based on Employment Insurance database finds that the rate of job creation declined over the period from 1999 to 2014 and that the job creation of small- and medium-sized enterprises fell sharply. This is partly explained by entry of fewer firms than before given that young firms tend to experience rapid employment growth. In fact, it is confirmed that the share of firms under age 6 in employment level and job creation declined. The finding that young firms employ young workers more than old firms suggests that a smaller role of young firms in the economy had a negative effect on youth employment.

• Journal of Adhesion and Interface
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• v.3 no.2
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• pp.40-44
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• 2002

We invested effect of the keeping-time of uncured composite and thermal aging, of cured composite on adhesive strength for rubber-brass coated steel cord composite in this study. We also evaluated how the adhesive strength affects to tire endurance. Using PAD adhesion specimen, peel adhesive strength was measured. The uncured composite was kept for several days up to 35 days in factory. Cured composite was also kept for 5 and 10 days at $85^{\circ}C$ in dry oven. Peel adhesive strength was decreased with increasing keeping-time and showed lower value with increasing thermal aging time. The lower peel adhesive strength, the lower tire-endurance. This fact was caused by the humidity and thermal aging which affected in the decrease of adhesive strength of the rubber-steel cord composite and resulted in interface fracture between rubber and steel cord. This phenomenon was confirmed from SEM investigation and tire-endurance. It was just known that corrosion of steel cord's surface and aging of adhesive layer strongly affected to decrease of adhesive strength. This resulted in directly decreasing tire-endurance.

• Korean Journal of Plant Resources
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• v.25 no.4
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• pp.482-489
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• 2012

Effect of Trichosanthes kirilowii extract on the inflammatory responsse was investigated in the lipopolysaccharide (LPS)-treated broiler chickens. Plasma ceruloplasmin and ${\alpha}$-acidic protein concentrations of all the experiment groups were increased at 3, 9 and 24h after LPS treatment. Plasma ceruloplasmin and ${\alpha}$-acidic protein concentrations of Trichosanthes kirilowii extract groups were lower than those of control group. Plasma nitrogen oxide concentration of all the experiment groups was rapidly increased at 3h after LPS treatment. However, plasma nitrogen oxide concentration was decreased at 3 and 9h after LPS treatment with increasing amount of Trichosanthes kirilowii extract added. Liver IL-2 mRNA concentration of all the experiment groups was rapidly increased at 2h after LPS treatment, and then gradually decreased to the level similar to that before LPS treatment at 9h after LPS treatment. Liver IL-2 mRNA concentration of Trichosanthes kirilowii extract groups were lower than that of control group. Spleen IL-2 mRNA concentration was the highest at 4h after LPS treatment in all the experiment groups. Spleen IL-2 mRNA concentration of 0.2 and 0.3% Trichosanthes kirilowii extract groups were higher than that of 0.1% Trichosanthes kirilowii extract group and control group at 3 and 4h after LPS treatment. Liver and spleen IFN-${\gamma}$ mRNA concentrations were increased at 2 and 3h after LPS treatment, decreased at 4h after LPS treatment, and then reached to the level similar to that before LPS treatment at 9h after LPS treatment. Liver and spleen IFN-${\gamma}$ mRNA concentrations of Trichosanthes kirilowii extract group were lower than those of control group at 2h and 3h after LPS treatment. Liver and spleen iNOS mRNA concentrations were the highest at 3h after LPS treatment, and then decreased to the level similar to that before LPS treatment at 9h after LPS treatment. Liver and spleen iNOS mRNA concentrations of Trichosanthes kirilowii extract groups were lower than those of control group at 2, 3 and 4h after LPS treatment.