• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.41 no.7
• /
• pp.469-480
• /
• 2017

For accurate AEP prediction in a wind farm, it is necessary to effectively calculate the wind speed reduction and the power loss due to the wake effect in each wind direction. In this study, a computer program for AEP prediction considering directional wake effect was developed. The results of the developed program were compared with the actual AEP of the wind farm and the calculation result of existing commercial software to confirm the accuracy of prediction. The applied equations are identical with those of commercial software based on existing theories, but there is a difference in the calculation process of the detection of the wake effect area in each wind direction. As a result, the developed program predicted to be less than 1% of difference to the actual capacity factor and showed more than 2% of better results compared with the existing commercial software.

• Proceedings of the Korean Society of Fisheries Technology Conference
• /
• 2001.10a
• /
• pp.181-182
• /
• 2001

세계식량기구(FAO)에 의하면, 해조류의 생산량은 연간 2천만톤이며, 국내 생산량은 연간 약 80만톤에 이른다. 이 중 미역, 김, 다시마는 주요 양식 대상종으로 주로 식품으로 소비되고 있는 해조류들이다. 최근 해조를 위시한 해양생물에는 육상생물과는 다른 약효활성이 있는 것으로 주목받아 많은 연구가 진행되고 있다(박종철 등, 2000, Unson, M. D. et al., 1993). 항균활성을 나타내는 본체는 다양하여 GRP(galactose-rich polysaccharide)(Gerlach, D. et al., 1994), flavonoid (Calzada, F., 1999) 등 여러 대상으로 연구되고 있다. (중략)

• Journal of Korean Society for Geospatial Information Science
• /
• v.21 no.4
• /
• pp.65-71
• /
• 2013

Wind shear means the variation of wind speed according to the height. Wind shear is the important factor affecting the energy production of wind turbines. Power Law is used to extrapolate wind speed data. Normally, a Power Law exponent of 0.143 is used and this is referred to as the 1/7th Power Law. The Power Law exponent is affected by atmospheric stability and surface roughness of the site. Thus, it is necessary to calculate the Power Law exponent of the site exactly for an accurate estimation of wind energy. In this study, wind resources were measured at the three Met-masts which were located in the coastal area of northeastern Jeju Island. The Power Law exponents of the sites were calculated and proposed using measured data. They were 0.141 at Handong, 0.138 at Pyeongdae, and 0.1254 at Udo. We compared annual energy productions which are calculated using a Power Law exponent of 0.143, the proposed value of the Power Law exponents for each site, and the measured data. As a result, the cases of calculating using the proposed values were more similar to the cases using the measured data than the cases using the 0.143 value. Finally, we found that the propsed values of the Power Law exponent are available to more accurately estimate wind resources.

• The Korean Journal of Malacology
• /
• v.13 no.2
• /
• pp.193-201
• /
• 1997

1990년 3월부터 1991년 2월까지 전라북도 군산 연안에 서식하는 동죽을 채집하여, 순간성장율, 순간사망율, 평균 생체량, 연간 생물생산력에 대하여 조사하였다. 치패는 각장 약 0.75 mm가 7월에 처음 채집되었으며, 0-5세의 6개 cohort로 구분되었다. 순간성장률은 여름철에 ？고 겨울철에 낮았지만, 순간사망률은 여름철에 높았다. 조사지역에서 동쪽 개체군의 연간평균 생체량은 3.865 g/$m^2$이었으며, 연간생산량은 3.933 g/$m^2$이었고, 연간 회전율은 1.020, 회전시간은 0.986년으로 추정되었다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.58.2-58.2
• /
• 2011

본 연구에서는 5MW급 수평축 풍력터빈 블레이드에 대해 국내 서남해안의 풍속특성을 고려한 최적설계를 수행 하였다. 최적설계를 수행하기 위해 블레이드 해석은 Blade Element and Momentum Theory를 이용 하였으며, 설계 시 적용된 기저형상은 NREL에서 제안한 5MW급 풍력터빈 블레이드을 선정하였다. 최적설계를 수행하기 전 설계에 사용된 설계변수들이 풍속에 대해 어떠한 경향을 가지고 있는지 알아보기 위해 Parametric Study를 수행 하였으며, 최적설계는 다목적 최적화 유전 알고리즘인 NSGA-II를 이용하여 평균풍속이 낮은 서남해안의 연간에너지 생산량과 설비이용률을 최대화하였다. 최적화 결과들로부터 설계 조건에 맞는 최적해를 도출 할 수 있었으며, 이를 통해 기저형상의 연간에너지 생산량 및 설비이용률을 보다 향상 시킬 수 있었다.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.6
• /
• pp.545-550
• /
• 2012

Wind resource assessment is necessary when designing wind farm. To get the assessment, we must use a long term(20 years) observed wind data but it is so hard. so that we usually measured more than a year on the planned site. From the wind data, we can calculate wind energy related with the wind farm site. However, it calculate wind energy to collect the long term data from Met-mast(Meteorology Mast) station on the site since the Met-mast is unstable from strong wind such as Typhoon or storm surge which is Non-periodic. To solve the lack of the long term data of the site, we usually derive new data from the long term observed data of AWS(Automatic Weather Station) around the wind farm area using mathematical interpolation method. The interpolation method is called MCP(Measure-Correlative-Predict). In this study, based on the MCP Regression Model proposed by us, we estimated the wind energy at Handong site using AEP(Annual Energy Production) from Gujwa AWS data in Jeju. The calculated wind energy at Handong was shown a good agreement between the predicted and the measured results based on the linear regression MCP. Short term AEP was about 7,475MW/year. Long term AEP was about 7,205MW/year. it showed an 3.6% of annual prediction different. It represents difference of 271MW in annual energy production. In comparison with 20years, it shows difference of 5,420MW, and this is about 9 months of energy production. From the results, we found that the proposed linear regression MCP method was very reasonable to estimate the wind resource of wind farm.

• The Korean Journal of Ecology
• /
• v.28 no.5
• /
• pp.265-270
• /
• 2005

In order to investigate the organic carbon distribution, net primary production, annual litter production, organic carbon in litter layer, soil organic carbon and soil respiration were studied in an oak forest, Kongju, Chungnam Province in Korea. Net primary production was estimated to 15.84 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$. The amount of carbon allocated to leaf and reproductive organ, branch, stem and root was 1.71, 4.03, 7.34, 2.76 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$ respectively. Annual litter production was 5.21 $ton{\cdot}ha^{-1}{\cdot}yr^{-1}$, which amounted to 2.35 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$. Average amount of organic carbon in litter layer (L+F) was 6.06 ton C/ha, and that of L layer decreased from winter through summer. Soil organic carbon decreased along the soil depth. Average amount of soil organic carbon in this oak forest was 165.19 ton C/ha. The amount of carbon evolved through soil respiration was 11.24 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$. Net amount of 4.60 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$ was absorbed from the atmosphere by this oak forest.

• Bulletin of Korea Environmental Preservation Association
• /
• v.10 no.10
• /
• pp.16-24
• /
• 1988

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.02a
• /
• pp.131-136
• /
• 2003

쌀은 우리 국민의 주식이자 단일 작물로써 재배면적이 가장 많은 105-110만㏊ 수준에 연간 생산량도 500만톤 이상을 꾸준히 유지하고 있는 중요한 식량작물이자 농가의 주 소득원이다. 그러나 이렇게 쌀의 생산량은 꾸준한데 비해 국민의 식생활이 점차 인스턴트 화되고 육류소비가 증가하면서 연간 쌀 소비량이 1990년 119.6kg에서 2002년 87.0kg으로 급격히 감소추세를 보임으로써 2002년도 기준으로 약 1,190만석의 재고가 발생하고 있다. 더욱이 WTO출범이후 MMA 물량이 2002년 125만석에 이르렀고, 2005년 이후 더욱 증가 할 것으로 예상되고 있어 국내 쌀 시장은 이제 과잉공급시대에 직면하고 있다. (중략)

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.647-648
• /
• 2008

풍력발전기 최적 설계시, 해석특성상 발생하는 막대한 계산 시간문제를 개선하기 위해, 본 논문에서는 최대 연간 에너지 생산량(AEP)을 위한 풍력발전기 최적설계를 빠른 탐색 기법인 MADS(Mesh Adaptive Direct Search)를 기반으로 최적화를 수행하였다. 또한, MADS와, 병렬 분산컴퓨팅 시스템과 결합된 유전알고리즘(Genetic Algorithms)간의 최적화 수행시간을 비교하였다.