• Structural Engineering and Mechanics
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• 제64권4호
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• pp.461-472
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• 2017

The dynamic tests of recycled aggregate concrete (RAC) are carried out, the rate-dependent mechanical models of RAC are proposed. The dynamic mechanical behaviors of RAC frame structure are investigated by adopting the numerical simulation method of the finite element. It is indicated that the lateral stiffness and the hysteresis loops of RAC frame structure obtained from the numerical simulation agree well with the test results, more so for the numerical simulation which is considered the strain rate effect than for the numerical simulation with strain rate excluded. The natural vibration frequency and the lateral stiffness increase with the increase of the strain rate. The dynamic model of the lateral stiffness is proposed, which is reasonably applied to describe the effect of the strain rate on the lateral stiffness of RAC frame structure. The effect of the strain rate on the structural deformation and capacity of RAC is analyzed. The analyses show that the inter-story drift decreases with the increase of the strain rate. However, with the increasing strain rate, the structural capacity increases. The dynamic models of the base shear coefficient and the overturning moment of RAC frame structure are developed. The dynamic models are important and can be used to evaluate the strength deterioration of RAC structure under dynamic loading.

• 산경연구논집
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• 제9권6호
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• pp.15-24
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• 2018

Purpose - The adjustment of one country's monetary policy can cause the macroeconomic change of other countries. Due to this, this paper attempts to analyze the impact of China's monetary policy on South Korea's exchange rate. Research design, data, and methodology - Based on the flexible-price monetary model, sets of annual time series from 1980 to 2017 are employed to perform an empirical estimation. The vector error correction model is also used to exploit the short-run relationship between both of them. Of course, the South Korea's real GDP, the China's real GDP, South Korea's interest rate, the South Korea's interest rate and the South Korea's monetary supply are treated as independent variables in this paper. Result - The long-run findings reveal that the China's money supply has a negative effect on South Korea's exchange rate. Respectively, the short-run findings depicts that the China's money supply has negative a effect on South Korea's exchange rate. Of course, other variables selected in this paper also have an effect on South Korea's exchange rate whatever positive or negative. Conclusions - As the empirical evidence shows, the China's monetary policy has a negative effect on South Korea's exchange rate whenever in the long run or in the short run.

• Genomics & Informatics
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• 제21권4호
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• pp.50.1-50.9
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• 2023

Vaccine development is one of the key efforts to control the spread of coronavirus disease 2019 (COVID-19). However, it has become apparent that the immunity acquired through vaccination is not permanent, known as the waning effect. Therefore, monitoring the proportion of the population with immunity is essential to improve the forecasting of future waves of the pandemic. Despite this, the impact of the waning effect on forecasting accuracies has not been extensively studied. We proposed a method for the estimation of the effective immunity (EI) rate which represents the waning effect by integrating the second and booster doses of COVID-19 vaccines. The EI rate, with different periods to the onset of the waning effect, was incorporated into three statistical models and two machine learning models. Stringency Index, omicron variant BA.5 rate (BA.5 rate), booster shot rate (BSR), and the EI rate were used as covariates and the best covariate combination was selected using prediction error. Among the prediction results, Generalized Additive Model showed the best improvement (decreasing 86% test error) with the EI rate. Furthermore, we confirmed that South Korea's decision to recommend booster shots after 90 days is reasonable since the waning effect onsets 90 days after the last dose of vaccine which improves the prediction of confirmed cases and deaths. Substituting BSR with EI rate in statistical models not only results in better predictions but also makes it possible to forecast a potential wave and help the local community react proactively to a rapid increase in confirmed cases.

• 경영과학
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• 제26권3호
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• pp.11-21
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• 2009

In this paper, we proposed some valuable analysis results of cultivation campaign marketing in A mobile telephone company. The cultivation campaign marketing is a new outbound TM campaign strategy composed of 4 steps for new subscribers. During the analyses, attrition rate of A mobile company, outbound TM rejection rate, contact rate/call success rate and additional service attrition rate after subscription are measured as an effect of cultivation campaign. The results showed that there were no statistical significance in improving retention rate between customers experienced 4 step cultivation campaign and control group. However, the cultivation campaign had a better effect on improving response rate and success of selling additional service product of mobile company compared to general selling campaign. This is because cultivation campaign group had been taking care of from subscription time. It is suggested that cultivation campaign had better confined customers more likely to buy additional service to outbound TM for the sake of financial efficiency.

• 산경연구논집
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• 제9권7호
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• pp.33-42
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• 2018

Purpose - This paper aims to verify whether the Fisher effect and the international Fisher effect are significant between China and South Korea in the long and short run, respectively. Research design, data, and methodology - The annual and monthly data, respectively, are employed to conduct an empirical estimation under the fully modified ordinary least squares(FMOLS). The nominal interest rate is treated as an independent variable. The inflation rate is treated as a dependent variable. Results - The results exhibit whenever in the long or short run, the Fisher effect exists in China and South Korea. However, the Fisher effect in South Korea is more significant than that of in China. Meanwhile, an empirical analysis is also preformed to investigate the long-run and the short-run international Fisher effect between China and South Korea. The deviation from the equilibrium relationship is that the commodity market and the Financial market have started to integrate in China. But China's integrated level proved to be relatively lower. Conclusions - To exploit that the Fisher effect and the international Fisher effect hold between China and South Korea can help both countries deal with the sufferings from integration of the commodity market and the financial market.

• East Asian Economic Review
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• 제20권4호
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• pp.469-491
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• 2016

In this paper, we estimate the exchange rate exposure, indicating the effect of exchange rate movements on firm values, for a sample of 1,400 firms in seven East Asian countries. The exposure estimates based on various exchange rate variables, return horizons and a control variable are compared. A key result from our analysis is that the long term effect of exchange rate movements on firm values is greater than the short term effect. And we find very similar results from using other exchange rate variables such as the U.S. dollar exchange rate, etc. Second, we add exchange rate volatility as a control variable and find that the extent of exposure is not much changed. Third, we examine the changes in exposure to exchange rate volatility with an increase in return horizon. Consequently the ratio of firms with significant exposures increases with the return horizons. Interestingly, the increase of exposure with the return horizons is faster for exposure to volatility than for exposure to exchange rate itself. Taken as a whole, our findings suggest that the socalled "exposure puzzle" may be a matter of the methodology used to measure exposure.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1998년도 학술발표회 발표논문집
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• pp.243-249
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• 1998

This study was conducted for analyzing the influence of outside temperature upon shading effect of greenhouses by simulation. The simulation program was tested by comparing predicted values to measured values and applied the Korean standard wide span glasshouse. The shading effect according to the variation of outside temperature was different by shading method and rate. The increasing rate of inside temperature with different shading rate was nearly propotional to the increasing value of outside temperature. The outside shading effect was a little better than inside shading.

• Nuclear Engineering and Technology
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• 제53권6호
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• pp.1991-1999
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• 2021

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines. A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257)·A^0.585. The dose rate of gamma irradiation from ⁶⁰Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.

• 대한안전경영과학회지
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• 제11권4호
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• pp.261-267
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• 2009

The purposes of this article is to analyse how market competition of credit card company affect price(interest rate) and survival length of card users. This paper uses individual account data from a large Korean credit card company during the periods from 2002 to 2006. The findings of our study are as follows. First, market competition of credit card company have a negative effect with interest rate of credit card. Second, market competition of credit card company have a affirmative effect with survival length. Finally, The effect of Increasing delinquency rate due to price increase is smaller than decreasing delinquency rate due to extending survival length.

• 대한물리치료과학회지
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• 제10권1호
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• pp.206-211
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• 2003

The purpose of this study is the effect of massage therapy on the human autonomic nerve system by heart rate variability spectral analysis. This study were to effect autonomic nerve system before and after massage therapy in 12 health peoples. The effect of massage therapy were assessments through Heart Rate Variability (HRV; SA-2000E, Medicare, Korea) before and after the massage therapy by same massage therapist. Statistical techniques for data analysis were applied paired t-test. The 0.05 level of significance was used as the critical level for rejection of the null hypotheses for the study. On the basis of the results analyzed in this study, conclusions were drawn as follows; Rest Heart Rate was significantly decreased before and after massage therapy, but other variable were no statistical significances. These results suggest that massage therapy maybe be effective in reducing heart rate and activity in valgal tone.