• The Korean Journal of Ecology
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• 제8권3호
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• pp.133-140
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• 1985

Aboveground net productions of four stands in the coastal salt marsh of Incheon were estimated with three different methods: first method was to measure peak live standing crop; second to measure both live and dead standing crops; thrid to measure live and dead standing crops and dead disappearance as well. Net productions estimated by the first method were lowest with a difference of 28~50% from those by the third method. Whereas estimates by the second method approximated considerably to those by the third method with a difference of 4~15%. The third method figured out the highest values and seemed to be most appropriate in estimating net production of herbaceous community. Form these results it is known that live standing crop, dead standing crop and dead disappearance respectively accounted for about 60, 30, 10% of net production estimated by the third method. Annual net productions estimated by the third method for Suaeda japonica-Salicornia herbacea, Artemisia scoparia-Limonium tetragonum, Calamagrostis epigeios, and Sonchus brachyotus-Setaria viridis stand were 650, 1, 080, 1, 409 and 1, 126 g.$m^{-2}.yr^{-1}$, respectively.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.447-449
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• 2003

Remotely sensed data can be used to estimate biomass production using methodologies relating vegetation indices to light absorption or to leaf photosynthetic capacity. The considerations of both light absorption and photosynthetic capacity in remote sensing-based modeling to estimate biomass production or NPP was introduced based upon Monteith model NPP is one of a evaluation of land degradation. NPP was estimated from annual maximum NDVI by MODIS data. It was known that NPP of the grassland that except the forest and the farming ground was distributed between 50-200g /m2.

• Korean Journal of Hydrosciences
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• 제3권
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• pp.81-96
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• 1992

This study represents the methodology for feasibility analysis of small hydro power SHP plant. Cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP candidate site. The perfomance prediction model and construction cost estimation model for tunnel-type SHP plant were developed. Eight tunnel -type SHP candidate sites existing on Han-river were selected and surveyed for actual site reconnaissance. The performance characteristics and economical feasibility for these sites were analyzed by using developed models. As a result, it was found that the optimum design flowrate with the lowest unit generation cost for tunel-type SHP candidate site were the flowrate concerming with between 20% and 30% of time ratio on the flow duration curve. Additionally, primary design specifications such as design flowrate, effective head, capacity, annual averageload factor, annual electricity production were estimated and discussed for eight surveyed SHP candidate sites.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.494-497
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• 2012

A methodology to predict the output performance of small hydro power using treated effluent in wastewater treatment plant has been studied. Existing plant located Kyunggi-Do were selected and the output performance characteristics for these plants were analyzed. As a result, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power in wastewater treatment plant. Additionally, primary design specifications such as design flowrate, capacity, operational rate and annual electricity production were estimated and discussed.

• Fisheries and Aquatic Sciences
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• 제12권2호
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• pp.118-129
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• 2009

To develop a sustainable management model for oyster farming in Pukman Bay, Korea, we estimated the carrying capacity for oyster farming using food availability data. Optimal culture densities were calculated to be 124-133 individuals per unit flux area ($m^2$) and 310-330 individuals per string. The present annual production is approximately 1,038 tons/year, which is 87% of the estimated maximum yield of 1,193 tons/year. Therefore, considering annual fluctuations and a critical buffer to reduce ecological impacts, the current level is within optimal conditions. During periods of increased water temperature, energy demand was largely met by high primary production. The food supply significantly decreased as the harvest season approached, and 10 out of 21 oyster farms had a deficient food supply for at least 1 month. Therefore, these farms (39% of the farms within the bay) exceeded optimal densities.

• 한국수소및신에너지학회논문집
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• 제14권1호
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• pp.61-68
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• 2003

This paper presents the methodology to analyze flow duration characteristics and performance prediction technique for small hydro power(SHP) Plants and its application. The flow duration curve can be decided by using monthly rainfall data at the most of the SHP sites with no useful hydrological data. It was proved that the monthly rainfall data can be characterized by using the cumulative density function of Weibull distribution and Thiessen method were adopted to decide flow duration curve at SHP plants. And, the performance prediction technique has been studied and development. One SHP plant was selected and performance characteristics was analyzed by using the developed technique, Primary design specfications such as design flowrate, plant capacity, operational rate and annual electricity production for the SHP plant were estimated, It was found that the methodology developed in this study can be a useful tool to predict the performance of SHP plants and candidate sites in Korea.

• 한국습지학회지
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• 제9권2호
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• pp.45-55
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• 2007

우포늪에서 2005년 5월부터 2006년 3월까지 수생 및 습생 관속식물을 대상으로 식물상과 생활형별 분포현황, 현존식생도 및 생활형별 분포 면적, 생활형별 연순생산성 및 1차생산을 조사하였다. 조사지역에 분포하는 수생 및 습생 관속식물은 우포 263종류, 목포 233종류, 사지포 244종류, 쪽지벌 182종류, 토평천 상류 190종류, 토평천 하류 178종류 등으로 85과 224속 287종 42변종 4품종 등 총 333 종류가 확인되었다. 관속식물을 생활형별로 구분하면 수생식물 38종류, 습생식물 108종류, 육상식물 187종류 등이고, 수생식물을 생활형별로 구분하면 정수식물 20종류 부엽식물 6종류 부수식물 5종류 침수식물 7종류 등으로 구분되었다. 우포늪의 식물군락은 27개 군락으로 구분되었으며, 현존식생도에 나타난 군락별 분포 면적은 마름-붕어마름 군락이 60.64 ha로 가장 넓고, 다음으로 생이가래-붕어마름 군락 32.91 ha, 줄 군락 30.05 ha 등의 순이었으며 생활형별로는 부수식물이 차지하는 면적이 172.6 ha(47.9%)로 가장 넓었다. 수생 및 습생 관속식물의 1차 생산량은 총 1,383.3 ton이고, 그 중 수생식물은 정수식물 564.1 ton(40.8%), 부수식물484.1 ton(34.9%), 부엽식물 146.7 ton(10.6%), 침수식물 1.3 ton(0.5%) 등의 순이었으며, 습생식물의 1차생산량은 182.1 ton(13.2%)이었다. 이들 수생 및 습생식물들은 대부분 현재의 늪 환경에 적응된 종이므로 늪의 육상화가 진행될 경우 종조성의 변화를 포함하여 생태계에 미치는 악영향이 예상되므로 늪의 보전 대책 및 보존 방안이 요망된다.

• Journal of Plant Biology
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• 제18권3호
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• pp.101-108
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• 1975

The nitrogen economy and primary production of a Helianthus annuus "Manchurian" population were studied with special reference to the pattern of seasonal changes of vertical distributions of dry matter and nitrogen quantities, and its quantitative significance was discussed in relation to the pattern of the plant population growth, distribution ratios among organs, and turnover rates of dry matter and nitrogen. The population was established in plant density of 11.1plant/$m^2$ at the experimdntal field of Kyungpook National University, Daegu. During the period of population developemnt (April-September, 1973), the annual inflow rates and outflow rates of dry matter and nitrogen were 5560 gDM/$m^2$/year and 89 gN/$m^2$/year, respectively. The distribution ratios of dry matter and nitrogen to leaves were 28% and 45%, to stems 48% and 18%, to roots 13% and 5%, and to flowers and seeds 11% and 32%, respectively. The maximum turnover rates of inflow of dry matter and nitrogen were attained in May-June, and were 216%/month and 210%/month, respectively. The amount of nitrogen demand was 52gN/$m^2$/year (58%) for the foliage growth, 13 gN/$m^2$/year(15%) for the stem growth, 20 gN/$m^2$/year(23%) for the reproductive organs, and 4 gN/$m^2$/year(4%) for the growth of the underground parts. The amount of nitrogen supply by the nitrogen withdrawn from senescing leaves and stems was 25gN/$m^2$/year(28%) and the amount of nitrogen absorption by the root from the environmental soil was 64 gN/$m^2$/year(72%). The ratiio of the a mount of produced dry matter to that of assimilated nitrogen during a year was calculated for this annual plant population as 60, which can be used as the nitrogen utility index.ity index.

• The Korean Journal of Ecology
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• 제12권4호
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• pp.245-256
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• 1989

Nitrogen cycling was in vestigated in Piuns koraiensis plantations with different ages, 1, 2, 3, 6, 9 and 11 years, which were reforested after clear-cutting. Annual N input by bulk precipitation was 10kg., and output by runoff decreased as the plantation aged, especially in-N. The standing N content of the whole vegetation increased approximately 5 times through 11 years. Understory surpassed P. koraiensis plants in the distribution of standing N content for the initial 9 years, but reversed thereafter. Annual N uptake of P. koraiensis plants increased greatly through 11 years, but that of understory increased somewhat until 9 years and decreased thereafter. The maximum N uptake of the whole vegetation was made in the 9-yr-old plantation. In the 1-yr-old one, 59% of the maximum was already absorbed by understory which mainly consisted to herbs. The recycling coefficient, ratio of annual return to rptake, of the whole vegetation decreased as the plantation aged and the value of understory was greater than that of P koraiensis plants. On the contrary, the N use efficiency, ratio of the net primary production to N uptake, of the whole vegetation increased as the plantation aged and the value of understory was less than that of P. koraiensis plants. Consequently, it is emphasized that understory played an important role in such plantation reforesred after clear-cutting for the initial 9 years.

• The Korean Journal of Ecology
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• 제28권5호
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• pp.265-270
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• 2005

삼림생태계의 유기탄소 분포를 파악하기 위하여, 공주지역 상수리나무림에서 연순생산량, 연간 낙엽생산량, 임상 낙엽층의 유기탄소량, 토양의 유기탄소량, 연간 토양호흡량을 조사하였다. 조사기간 중 상수리나무림의 순일차생산량은 15.84 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$으로 추정되었으며, 잎과 생식기관, 가지, 줄기, 뿌리에 각각 1.71, 4.03, 7.34, 2.76 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$이 배분되었다. 연간 낙엽생산량은 5.21 $ton{\cdot}ha^{-1}{\cdot}yr^{-1}$이었으며, 생산된 낙엽을 통해 연간 임상으로 이입되는 유기탄소량은 2.35 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$이었다. 상수리나무 임상 낙엽층의 평균 유기탄소량은 6.06 ton C/ha로 조사되었으며, L층의 유기탄소량은 동절기에서 하절기로 갈수록 감소하는 경향을 보였다. 토양층별 유기탄소 함량은 표층에서 하층으로 갈수록 낮아졌으며, 본 상수리나무림 토양의 단위면적당 유기탄소량은 165.19 ton C/ha로 조사되었다. 상수리나무림은 토양호흡을 통해 연간 11.24 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$를 대기 중으로 방출하였다. 조사지 상수리나무림은 대기 중으로부터 연간 4.60 ton $C{\cdot}ha^{-1}{\cdot}yr^{-1}$을 순흡수 하였다.