• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1385-1400
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• 2013

This paper discusses income replacement ratios of national pension, retirement pension and individual annuities in Korea. These ratios are useful indicators for the assessment of retirement income security of workers. This paper projects income replacement ratios, using the pension entry rate, decrement rates, and life tables of the National Statistical Office. The result of the actuarial projection is that the income replacement ratio of national pension is approximately 21.0 to 22.7%, that the income replacement ratio of retirement pension is about 5.8 to 9.7%, and that the income replacement ratio of an individual annuity is about 13.5 to 21.0%, respectively. The income replacement ratio by income varies due to the effects of income redistribution in national pension and retirement pension, but the income replacement ratio of an individual annuity is constant, regardless of income.

• Journal of Aquaculture
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• v.13 no.3
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• pp.239-244
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• 2000

To test survival growth of juvenile abalone, five different diet were constituted. Diet 1, the control, was constituted with white fish meal (15%), soybean meal (25%) and wheat flour (25%); diets 2,3 and 4 were constituted to replace each one of these ingradietns by supplementing Sargossum powder (upto 10 %) and the fifth one by Undularia powder. Survival of these abalones differed significantly. Diet 4 supported the fastest growth. There was no significant difference in the composition of these abalones hence Sargassum can be used as a substitute.

• Korean journal of communication and information
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• v.24
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• pp.37-67
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• 2004

본 연구는 인터넷 이용수준이 전통적 미디어의 이용수준에 미치는 영향과 수용지들의 미디어 소비 패턴에 대해 살펴보았다. 미디어 대체이론, 이용과 충족이론, 미디어 레퍼토리 연구를 바탕으로 인터넷 이용이 전통적 미디어의 이용에 미치는 영향을 중심으로 개인들의 정보와 오락 미디어 레퍼토리, 인터넷 레퍼토리에 영향을 미치는 사회적, 심리/태도적 변인과 인구통계학적 특징 등도 검토하였다. 이를 위해 전국에 있는 18세 이상 성인들을 대상으로 성별, 나이별, 지역별 층화표집방법을 이용해 표본을 추출하고 500개의 유효 서베이 설문지를 수집하였다. 데이터의 분석결과, 인터넷 이용정도가 다른 매체에 미치는 영향은 각 미디어별로 세 가지 다른 양상을-상호보완적 영향, 대체 치환의 영향, 그리고 영향을 받지 않음-보였으나 대체로 인터넷은 다른 미디어의 대체 미디어라기보다는 보완적인 매체로 현재 이용되고 있음이 나타났다. 또, 전반적인 미디어 이용시간 측면에서는 인터넷을 많이 이용하는 응답자일수록 오락과 정보 미디어 레퍼토리 크기가 더 컸던 것으로 나타나, 현재까지는 인터넷이 다른 미디어와 상호 보완하는 양상, 피들러(Fidler)의 미디어 변형이론 가운데 공존 공진화 현상을 보여주었다. 응답자들은 평균 2.01개와 2.25개의 오락과 정보 미디어 레퍼토리를 가졌으며 텔레비전, 신문, 인터넷을 두 미디어 레퍼토리의 3대 주요 미디어로 꼽았다. 또한 인터넷 레퍼토리와 사회적, 태도적 변인들간의 상관관계는 최근의 이용 충족이론과 미디어 레퍼토리 연구에서 나타났던 결과들과 일치해 사회적, 심리 태도적 요인들이(친밀도, 접근성, 유용성, 여가시간) 미디어 레퍼토리의 크기에도 영향을 미친다는 사실이 검증되었다.

• Communications for Statistical Applications and Methods
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• v.15 no.2
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• pp.255-264
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• 2008

It is common in practice to use mean squared error(MSE) for prediction. Recently, Park and Shin (2005) and Jones et al. (2007) studied prediction based on mean squared relative error(MSRE). We proposed a new nonparametric way of prediction based on MSRE substituting Jones et al. (2007) and provided a small simulation study which highly supports the proposed method.

• Journal of the Speleological Society of Korea
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• v.16 no.17
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• pp.96-108
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• 1988

동굴은 항상 폐쇄된 세계로 항온, 항습, 항암의 지하세계이므로 특수한 환경을 이루고 있다. 즉 동굴의 온도는 년중 거의가 일정하고 햇빛이 없는 캄캄한 암흑의 세계라는 것이 하나의 특색이다. 대체로 동굴의 대기는 기류의 움직임이 매우 느린 관계로 해구부근에는 대기온도와 동굴의 온도가 크게 달리 나타나지만 차차 안으로 들어가면서 동굴내의 대기온도는 동굴벽, 즉 동굴의 온도와는 거의가 비슷하게 나타난다. 이 때문에 굴속 깊은 지점의 온도는 석회암의 온도와 관계되고 있으며 그 온도는 대체로 지표의 년간 평균기온과 비슷하다.(중략)

• Journal of Labour Economics
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• v.27 no.1
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• pp.165-179
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• 2004

While they compare the growth rate of wage with that of average labor productivity, we compare it with the growth rate of marginal labor productivity. After estimating the elasticity of substitution and technology level, we estimate the marginal labor productivity. Wages and marginal labor productivities are similar over 1963-2000. However, while wages come short of marginal labor productivities over 1963-1986, they exceed marginal labor productivities over 1987-2000. Although the growth rate of wage is not so different from that of marginal labor productivity, it can be disparate from that of average labor productivity. Therefore the former exceeding the latter does not mean the excessive wage growth off the labor demand curve.

• Journal of Life Science
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• v.16 no.1
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• pp.22-29
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• 2006

Effect of microbial products made of Bacillus stearothermophilus DL-3 on growth of chickens and pigs was investigated. Two types of microbial product were made in this study. One is the microbial product made of culture broth of B. stearothemophilus DL-3 and rice bran which named as the microbial product A. The other is the microbial product made of culture broth of B. stearothermophilus DL-3, apple pomace, soybean pomace and rice bran which named as the microbial product B. Chickens were divided into three groups and each group was fed with $100\%$ general feed, $90\%$ general feed supplemented with $10\%$ microbial product A or $90\%$ general feed supplemented with $10\%$ microbial product B. The average chicken weight of each group was $41.1{\pm}2.5g,\;41.6{\pm}3.2g\;and\;42.3{\pm}2.9g$ and those after 28 days was $547.7{\pm}91.7g,\;560.1{\pm}17.2g\;and\;562.2{\pm}32.5g$, respectively. The average weight gain for each group was 506.6 g, 518.6 g and 519.9 g, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $2.4\%\;and\;2.6\%$ higher than the group fed with $100\%$ general feed. Pigs were also divided into three groups and each group was fed like chickens. The average weight of each group was $9.3{\pm}1.0kg,\;9.4{\pm}1.1kg\;and\;9.6{\pm}1.0kg$ and those after 37 days was $19.3{\pm}4.1kg,\;20.2{\pm}3.9kg\;and\;20.8{\pm}4.2kg$, respectively. The average Weight gain for each group was 10.65 kg, 10.82 kg and 11.20 kg, respectively, and weight increases of groups fed with $90\%$ general feeder and $10\%$ microbial product A and B were $1.6\%$ and $5.2\%$ higher than the group fed with $100\%$ general feed.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.313-321
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• 2009

The relationship between precipitation and groundwater level and the correlation between the moving average of precipitation and goundwater level were analyzed for the Han river watershed in Korean peninsular. Fourteen regions in the watershed were selected and there were somewhat different patterns of seasonal fluctuation of groundwater level data. The groundwater level data tends to decrease in dry spell and increase in wet spell however the range between maximum and minimum values is quite different for each gauging point. We could have stronger correlation between groundwater level for fractured rock aquifer and the moving average of precipitation than the groundwater level for alluvial aquifer. The critical infiltration, which is the maximum daily infiltration averaged throughout watershed, value is turned out to have the range of 10 to 90 mm. We could have stronger correlation when we consider critical infiltration and modify the original precipitation data than we use original precipitation data. We also could have higher correlation coefficient when we consider snowmelt effect for the watershed that has considerable snow event.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.3
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• pp.120-130
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• 2014

Change of mean sea level in the western coast of Korean peninsula was estimated with the observed tide data of the KHOA. The cause of the change was investigated. Mean sea levels in the western coast have been changed due to coastal development projects in the coastal zone. The estimated variations, which are significantly different regionally, vary from -6.8 cm in Incheon to 38 cm in Gunsan. The changing rate of mean sea level occurred by natural factors such as global warming varies from 1.1 mm/year in the north to 4.4 mm/year in the south of western coast of Korean peninsula. In Jeju, sea level rise and rise of sea temperature showed a close relationship. Water temperature rise of one degree increases mean sea level to 0.6 mm in Jeju. Rising rate of mean sea level has increased rapidly after the mid-1980s.

• Journal of the Korean Institute of Intelligent Systems
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• v.14 no.6
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• pp.789-792
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• 2004

In various fields as web mining, bioinformatics, statistical data analysis, and so forth, very diversely missing values are found. These values make training data to be sparse. Largely, the missing values are replaced by predicted values using mean and mode. We can used the advanced missing value imputation methods as conditional mean, tree method, and Markov Chain Monte Carlo algorithm. But general imputation models have the property that their predictive accuracy is decreased according to increase the ratio of missing in training data. Moreover the number of available imputations is limited by increasing missing ratio. To settle this problem, we proposed statistical learning theory to preprocess for missing values. Our statistical learning theory is the support vector regression by Vapnik. The proposed method can be applied to sparsely training data. We verified the performance of our model using the data sets from UCI machine learning repository.