This paper examines whether post-earnings-announcement drift (PEAD) in the Koeran Stock Market is a consequence of the risk premium for omitted latent risk factors or of systematic mispricing from investors' delayed response to earnings news. To examine whether PEAD is still prominent after adjustment for risk factors, we form portfolios (SUE1~SUE4) sorted on standardized unexpected earnings (SUE). We find that value-weighted average excess raw returns and cumulative abnormal returns tend to monotonically increase across SUE portfolios. Further, the difference in average excess return between highest and lowest SUE portoflios (i.e., SUE4−SUE1), which is the return of the SUE-based zero-investment strategy, is positive and statistically significant. We also find that riskadjusted abnormal returns, which are computed from the well-known three models (i.e., CAPM, Fama-French three-factor model, and Fama-French five-factor model), still show a monotonic increasing pattern across SUE portfolios. The difference in abnormal return between highest and lowest SUE portfolios is also positive and statistically significant. Therefore, these results indicate that it is difficult to argue that PEAD is a consequence of the risk premium for omitted risk factors in the Korean stock market. We also examine the effect of limits-to-arbitrage on PEAD, and find that as the degree of limits-to-arbitrage is more profound, the degree of the drift is more prominent. That is, the difference, SUE4−SUE1, tends to increase in magnitude and statistical signiciance with the degree of limits-to-arbitrage. Furthermore, the difference in SUE4-SUE1 between the most and least severe limits-to-arbitrage portfolios (i.e., difference-indifference) is positive and statistically significant. These results indicate that PEAD is more profound as limits-to-arbitrage becomes more severe. In summary, this paper provides evidence supporting the arguments that PEAD in the Korean stock market may be a consequence of delayed response to unexpected earnings news due to limits-to-arbitrage, rather than a manifestation of the risk premium for omitted latent risk factors. To our knowledge, this paper is the first in the literature in Korea that comprehensively evaluates the two explanations for PEAD.

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This study was carried out to find optimum roasting condition of sesame seeds for making seed season and oil treated with different temperatures and time intervals. Sesame seeds with 17~18% of moisture content were treated under fixed and changed roasting temperature conditions. The fixed temperatures are ranged from 160 to 240℃ with 20℃ intervals. The changed temperatures were treated at low(160 and 180℃) and medium(200 and 220℃) for 10 minutes, and at high(220 and 240℃) for 3 minutes. Meanwhile, roasting times were 20-30 minutes longer under low temperature condition and 3-5 minutes shorter under high temperature condition. The optimum roasting temperature and time were determined as 220℃ and 3 minutes for producing seed season, and as 220℃ and 5 minutes for sesame oil, respectively, in roasting with small quantity of sesame seeds. On the other hand, in the large scale roasting condition, those showed 240℃ and 15 minutes in for producing seed season, and 280℃ and 10 minutes and 260℃ and 15 minute for producing seed season in white-colored sesame variety and black-colored sesame variety, respectively.

This experiment was conducted to clarify the effect of the temperature for grain filling duration on quality and taste of cooked rice cultivated in different region in Korea. In 2006 and 2007, 4 mid-late maturing group of rice varieties (Nampyeongbyeo, Ilpumbyeo, Junambyeo and Dongjin 1) were cultivated in 28 experimental plots of 27 different regions located in 8 provinces. The taste of cooked rice were positively correlated with 1,000 grain weight but negatively correlated with protein content of brown rice. Mean temperature for 30 days from heading was more closely correlated with grain filling and tastes of cooked rice than those for 40 days. Though, the optimum mean temperature for the best taste of cooked rice for 30 days after heading was 22.1 to 23.1℃ depending on varieties, in general, 1,000 grain weight and cooked rice taste were the highest in the mean temperature of 22.2℃ for 30 days from heading. But grains were poorly ripened in case of the mean temperature lower than 21.0℃ for 30 days after heading. Therefore, for the better taste of cooked rice in Korea, the developing new rice varieties and cultivation method should be focused to adjust the mean temperature within 22-23℃ during the period of 30 days after heading.

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