• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.181.1-181.1
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• 2010

기후변화의 주요인이 되는 온실가스 감축을 목표로 화석연료를 대체하기 위한 대체 에너지 개발을 위한 많은 노력이 진행되고 있다. 풍력 에너지와 같은 신재생에너지는 이러한 하나의 해결 수단이 될 수 있으며 풍력 에너지 사업의 활성화를 위해서는 정확한 풍력 정보 제공이 우선이다. 풍력-기상자원지도는 풍력 발전에 유용한 정보 제공을 위한 목적으로 중규모 수치 모델을 이용하여 작성된다. 본 연구에서는 중규모 수치 모델의 정확도 향상을 위한 자료동화 방법으로써 Four-Dimensional Data Assimilation (FDDA) 방법을 이용한다. 풍력-기상자원지도는 공간분해능 1 km 해상도로 개발된다. 풍력-기상자원지도는 1998-2008년까지의 평균적인 상태에 대하여 모의를 하기 위하여 통계적인 방법으로 11년 기간의 평균과 유사한 기간을 선정하였다. 풍력-기상자원지도는 연 평균, 월 평균 풍속과 주 풍향, 주풍향 발생 비율 등의 정보를 제공한다. 우리나라 풍속의 평균 분포는 내륙 산악지역, 남해안, 제주도에서 강풍이 발생하며 주 풍향은 대체로 북서풍이다. 주 풍향의 발생비율은 산악 지역과 남 동해안에서 높아 풍력 발전의 최적지 정보를 제공한다. 1 km 해상도의 모델과 관측의 오차는 서해안 등의 해안지역보다 강원 산악지역에서 오차가 더욱 증가하였다. 이러한 산악 지역의 오차는 복잡한 지형에서는 1km 미만의 수 백 m 해상도 수치모의가 필요함을 지시한다. 따라서 본 연구에서는 WRF-LES 모형을 이용하여 333m 해상도의 기상자원지도를 개발한다. 333m 해상도의 자원지도 영역은 강원도 지역에 대하여 모의되었다. 333m 해상도의 풍속 분포는 1km 해상도의 풍속 분포와 비교하였을 때 풍속의 분포가 보다 세밀하게 표현되었다. 정량적인 검증을 하였을 때 관측소에 따라 차이는 있었으나 1km 해상도에서 과대 모의된 풍속의 분포가 현저히 개선이 되었으며, 시간적인 경향도 잘 일치함을 보였다.

• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.27-34
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• 2024

This study aims to propose an optimal asset allocation that minimizes the risk of insufficient realized replacement rates compared to the OECD average replacement rate. To do this, we set the shortfall risk of replacement rates and calculates an asset allocation plan to minimize this risk based on the period of enrollment, the income level and additional contribution. We consider stocks and deposits as investment assets, using Monte Carlo simulation with a GBM model to generate return distributions for stocks. Our result show that, for individuals with a enrollment period of less than 30 years, participants should invest a minimum of 70-80% of their funds in risky assets to minimize the shortfall risk. However, the proportion of funds that need to be invested in risky assets declines significantly when participants contribute an additional premiums. This effect is particularly pronounced among low-income individuals. Therefore, to achieve OECD average replacement rates, the government needs to incentivize participants to invest more in risky assets, while also providing policies to encourage additional contributions, especially for the low-income population.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.194-201
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• 2014

To elucidate which climate factors and what periods affect the time of breeding migration of Gori salamanders (Hynobius yangi), we have investigated relationships between the 5-years breeding monitoring data from 2006 to 2010 which had obtained in both natural and translocated breeding sites at Bongdae mountain, Gijang-gun, Busan-si and the matched climate data obtained from the weather station, approximately 25 km apart from the sites. Mean average and mean lowest temperatures during one month before the first breeding migration were related with the time of first female migration in the translocated site. Mean temperature variation and mean precipitation during 60~120 days before the first breeding migration affected the time of 30% male appearance at the natural site and the time of 30% female appearance at both natural and translocated sites. Climate factors were more closely related with female appearance than male and at the translocated site than at the natural site. Our results show that changes in mean temperature variation and mean precipitation rather than mean average temperature might more significantly affect the breeding migration of salamanders, female breeding migration is more closely related with climate factors, and the salamanders translocated could be more affected by climate changes than those in natural populations.

• Journal of the Korean Vacuum Society
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• v.3 no.1
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• pp.1-7
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• 1994

전자방출에서 에너지 교환과 역온도를 새롭게 계산하였다. 전자방출에서 대체전자들에 유용한 빈상태들을 만드는 요소로 터널링 효과를 이 계산에서 고려하였다. 그것은 방출부분에서 일어나는 대체 관정을 설명하기 위해서는 빈상태를 만드는데 터널링 기여가 필수적이기 때문이다. 이렇게 계산하여 온 도와 전장의 함수로 얻어진전자당 에너지 교환은 실험결과와 잘 일치하였다. 또한 전장의 함수로 얻어 진 역온도도 실험치와 만족할 만한 일치를 보여주었다. 이 결과는 대체전자들의 평균에너지에 대한 노 팅햄-플레밍과 헨더슨의 논쟁에서 후자의 견해를 지지하는 것이다.

• The Korean Journal of Applied Statistics
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• v.29 no.7
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• pp.1271-1281
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• 2016

Wins above replacement (WAR) is one of the most widely used statistic among sabermatrics statistics that measure the ability of a batter in baseball. WAR has a great advantage that is to represent the attack power of the player and the base running ability, defensive ability as a single value. In this study, we proposed a hitter ability index using the sabermetrics statistics that can replace WAR based on Korea Baseball Record Data of the last three years (2013-2015). First, we calculated Batter ability index through the arithmetic mean method, the weighted average method, principal component regression and selected the method that had high correlation with WAR.

• Journal of Hospice and Palliative Care
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• v.7 no.1
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• pp.37-48
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• 2004

Purpose: Population using complementary and alternative medicine (CAM) and the cost or it are increasing all over the world. In this study, we investigated the utilization state of CAM in the elderly people during the last 6 months of life. Methods: We found 4,210 persons in Seoul, older than 65 years who received a funeral subsidy from health insurance after death during the latter half of the year, 2001. We stratified them by age and gender and selected 301 persons and surveyed them by questionnaire. Results: 247 persons (83.1%) used at least one of CAM during their last 6 months of life. Diet and Nutrition remedy showed the highest utilatization rate (65.5%), and drug therapies also were much used (29.9%). Utilization rate was higher in female (60%) and according to the cause of death, the highest in a geriatric disease groups, and the lowest in the cancer group. Whole satisfaction to CAM was high with average 4.25 points out of total 6, and adverse effects were almost free with average 5.55 points out of total 6. Satisfaction was the highest in Diet and Nutrition remedy but the lowest in Manipulative and Body-Based methods. Adverse-effect score was best in Manipulative and Body-Based methods. According to age and the causative disease of death, there were significant differences in satisfaction and adverse effect levels. Conclusion: Majority of old people used at least one of CAM during their last 6months of life. Whole satisfaction and adverse-effect level were very excellent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.135-142
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• 1996

Two experiments were conducted to investigate the utilization of various types of fish meal as dietary protein sources in Korean rockfish (Sebastes schlegeli). In the first experiment, averaging 5.7 g fish were divided into two groups and fed one of diets containing $55\%$ steam-dried white fish meal (SWFM) or $55\%$ brown fish meal (BFM) for 45 days. Weight gain and feed efficiency from fish fed SWFM were significantly (P<0.05) higher than those from fish fed BFM diet. However, daily feed intake, protein retention and lipid retention were not influenced by the two different diets. In the second experiment, averaging 86.6 g fish were divided into six groups and fed one of diets containing $56\%$ SWFM, $28\%\;SWFM+31\%$ flame-dried white fish meal (FWFM), $62\%\;FWFM,\;28\%\;SWFM+31\%\;BFM,\;56\%\;BFM$, or $28\%\;SWFM+29\%$ hydrolyzed fish protein (HFP) for 21 weeks. No significant differences were found among fish fed the six different diets in weight gain, feed efficiency, condition factor, whole body composition, and relative liver weight. Results of the present studies indicated that fish size should be considered in selecting feed ingredients and also feed cost could be lowered by replacing SWFM with FWFM or BFM in growing Korean rockfish diet.

• The Korean Journal of Applied Statistics
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• v.21 no.1
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• pp.95-107
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• 2008

Survey on the rural living indicators was the statistic approved from National Statistical Office and the survey executed by rural resources development institute. This study was used the raw data of survey on the rural living indicators in 2005. After editing procedure for raw data, we were studied 1,582 households which is acquired through elimination of case included nonresponses, and imputed a nonresponses of 15 item selected from 146 item. The imputation methods and efficiency of imputation for simulation was adapted differently from type of data. For continuous data, we imputed the nonresponses with mean imputation, regression imputation, adjusted grey-based k-NN imputation(DU, DW, WU, WW) and compared the results with RMSE. For categorical data, we imputed the nonresponses with mode method, probability imputation, conditional mode method, conditional probability method, hot-deck imputation, and compared the results with Accuracy. By the results, regression imputation and adjusted grey-based k-NN imputation appropriated for continuous data and hot-deck imputation appropriated for categorical data.

• Explosives and Blasting
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• v.20 no.1
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• pp.5-14
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• 2002

파쇄 암석의 파쇄도는 발파효율을 나타내는 중요 척도로서 적재와 분쇄 작업에 큰 영향을 미친다. 그러나 현장에 쌓여 있는 발파암 더미로부터 파쇄도를 조사한다는 것은 용이한 작업이 아니다. 본 연구에서는 석산 발파에서 가장 중요한 요소인 천공방식과 암질의 변화가 파쇄도와 발파진동에 미치는 영향을 조사하였다. 파쇄 입도에 영향을 미치는 중요한 변수인 천공방식, 암질등급(RMR), 현지 암반의 블록 크기, 발파진동 등의 영향을 파쇄암의 평균입도(MFS)와 상위 5개의 대괴 평균치$(L_5)$로 나타내었다. 연구결과, 파쇄암의 평균입도는 상위 5개의 대괴 평균치와 선형적인 관계를 보였다. 발파방법과 파쇄도 평가 결과 재래식 발파에서는 파쇄도를 예측할 수 없었고 커다란 옥석이 생성되었으나, 벤치발파에서는 평균파쇄암의 크기가 비교적 양호한 파쇄 상태를 유지하였다. 현지 암반 블록 크기는 평균 파쇄암의 크기와 선형적 관계를 나타내었다. RMR값이 커짐에 따라 발파진동 추정식의 진동상수 K와 감쇠지수 n의 절대값과 평균 파쇄암의 크기, 그리고 상위 대괴의 크기는 대체적으로 증가하는 경향을 나타내었고, 진동상수 K와 감쇠지수 n도 증가하는 경향을 보였다.

• The Journal of the Korean bone and joint tumor society
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• v.9 no.2
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• pp.139-147
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• 2003

Purpose: The purpose of this study was to determine if bony union can be obtained when a bone graft substitute is transplanted in order to treat a benign bone tumor and if there is a difference between calcium sulfate and hydroxyapatite in the healing procedure when the degree of the bony union after the bone graft are compared. Materials and Methods: This study selected 20 cases, in which a curettage on the benign bone tumors was conducted and a bone graft substitute was transplanted. The area of the focus, the new bone formation, the recurrence of the focus in the plain radiographs and histological findings were observed. Results: Twenty cases (13 males, 7 females) were evaluated. Their mean age at surgery was 15.8 years (2~45), and the mean follow-up period was 3 years. The mean area of focus was 30.7 $cm^3$ in the radiographs, and 19 cases showed successful results in the ultimate visit, while 1 case has a recurrence of the focus. Conclusion: Calcium sulfate has osteoconduction and superior bioavailability, and is absorbed in vivo in proportion to the new bone formation. On the other hand, hydroxyapatite has good osteoconduction. It can result in better bone formation when it is combined with an autologous bone graft, autologous bone marrow, and an allogenic bone graft, but is absorbed in vivo more slowly than the former.