• Title, Summary, Keyword: net production

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A comparison of Production and Solar Energy Utilization among Young Pinus koraiensis Plantations of Different Ages (잣나무 유림의 수령에 따른 생산량 및 태양에너지 이용효율 비교)

  • Kim, Yong-Tage;Seung-Woo Lee;Joon-Ho Kim
    • The Korean Journal of Ecology
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    • v.11 no.2
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    • pp.83-95
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    • 1988
  • Phytomass, annual net production, respiration, annual gros production and litter fall were estimated in young Korean pine (Pinus koraiensis) plantations reforested 1,2,3,6,9 and 11 years ago, respectivly. The estimated phytomasses in terms of allometry were 0.07, 0.44, 0.58, 13.37, 32.26 and 48.42ton/ha/yr for annual net production and those of understory with harvest method were 3.70, 4.52, 5.28, 6.72, 7.56 and 5.72ton/ha for standing phytomass and 5.01, 4.71, 5.52m 6.15, 4.51 and 2.08 ton/ha/yr for annual net production at 1,2,3,6,9 and 11 year old plantation, respectively. Although the standing phytomass of understory increased gradually until 9 years thereafter decreased, that of white pine increased suddenly from 6 years after reforestation. The ratios of the annyal net production of understory to that of white pine were 71.57, 1.48 and 0.23 at 1,6 and 11 year old plantations, respectively. The net production in calorie value for whole vegetation of the plantations, respectively. The net production in calorie value for whole vegetation of the plantations increased until 9 years thereafter decreased; i.e. 224, 221, 280, 466, 527 and 494X105 kcal/ha/yr at 1,2,3,6,9 and 11 year old plantation, respectivey. The ratio of annual net production to annual gross production of the undersoty was lower than that of the pine at the same plantation age. Efficiency of solat energy untilization for net production by the pine was lower than that by understory y\until six ear old plantation but that was vice versa over 9 year old plantation. That for gross producrion by the pine was lower than that by the unsersotry at all plantations.

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Predicting Net Income for Cultivation Plan Consultation

  • Lee, Soong-Hee;Yoe, Hyun
    • Journal of information and communication convergence engineering
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    • v.18 no.3
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    • pp.167-175
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    • 2020
  • The net income per unit area from crop production could be the most critical consideration for agricultural producers during cultivation planning. This paper proposes a scheme for predicting the net income per unit area based on machine learning and related calculations. This scheme predicts rice production and operation costs by applying climate and price index data. The rice price is also predicted by applying rice production and operation cost data. Finally, these predicted results are employed to calculate the predicted net income, which is compared with the actual net income. Consequently, the proposed scheme shows a meaningful degree of conformity, which indicates the potential of machine learning for predicting various aspects of agricultural production.

Biomass and Net Primary Production of Quercus acutissima Natural Forest Ecosystems in Pohang (포항 지역의 상수리나무 천연림 생태계의 물질생산에 관한 연구)

  • 박관수;권기원;송호경
    • Journal of Korea Foresty Energy
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    • v.21 no.1
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    • pp.25-31
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    • 2002
  • This study was carried out to estimate aboveground biomass and net primary production in an average 37-year-old Quercus acutissima stand of Pohang area. Ten sample trees were cut in the forest and soil samples were collected in August, 2001. Estimation for aboveground biomass and net primary production was made by the equation model Wt=$aD^b$ where Wt is ovendry weight in kg and D is DBH in cm. Total aboveground biomass was 115.47ton/ha in the study forest. The proportion of each tree component to total aboveground biomass was high in order of bolewood(63.9%), branches(19.8%), bolebark(16.2%) and leaves(1.2%) in the study forest. Aboveground total net primary production was estimated at 7.89ton/ha in the study area. The proportion of each tree component to total net primary production was high in order of bolewood, bolebark, branch, and leaves.

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Multistage Fuzzy Production Systems Modeling and Approximate Reasoning Based on Fuzzy Petri Nets (다단계 퍼지추론 시스템의 퍼지 페트리네트 모델링과 근사추론)

  • 전명근
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.12
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    • pp.84-94
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    • 1996
  • In this work, a fuzzy petri net model for modeling a general form of fuzzy production system which consists of chaining fuzzy production rules and so requires multistage reasoning process is presented. For the obtained fuzzy petri net model, the net will be transformed into some matrices, and also be systematically led to an algebraic form of a state equation. Since it is fond that the approximate reasoning process in fuzzy systems corresponds to the dynamic behavior of the fuzzy petri net, it is further shown that the multistage reasoning process can be carried out by executing the state equation.

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A preparatory study on fish behavioral properties in a set-net

  • KANG, Myounghee;LIU, Jenming;HASSAN, Raja Bidin bin Raja;FAJARYANTI, Rina;HWANG, Bokyu
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.56 no.2
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    • pp.105-113
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    • 2020
  • The fish influx and behavioral properties at a set-net off Goseong, South Korea were investigated using an imaging sonar. As a result, the average influx of fish was 33.9% at day time and 66.1% at night time, respectively, which indicated that a majority of fish entered into a playground in the set-net at night. The fish behavioral properties such as target (fish) length, range, orientation and major-axis angle were examined and compared among survey dates (4, 5, and 6 June 2019) using the statistical analysis tool (analysis of variance, ANOVA). The behavioral properties presented differently sometime of survey dates. This is preparatory study to support fish behavior properties in a set-net. It is expected that more elaborated behavioral information of fishes in the set-net is beneficial for designing and deploying a set-net fishing gear as well as general fish behavior research in the future.

Comparison of Estimation Methods for Primary Net Production at Herbaceous Coastal Marsh Vegetation (海安 鹽濕地 植生의 純生産性 推定法의 比較)

  • Ryu, Beung Tae;Joon-Ho Kim
    • The Korean Journal of Ecology
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    • v.8 no.3
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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.

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Biomass and Net Production of a Natural Quercus mongolica Forest in Namsan, Seoul (서울 남산지역 신갈나무 천연림의 물질생산)

  • Park In-Hyeop;Kim Dong-Yeob;Son Yow-han;Yi Myong-Jong;Jin Hyun-O;Choi Yun-Ho
    • Korean Journal of Environment and Ecology
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    • v.19 no.3
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    • pp.299-304
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    • 2005
  • Biomass and net production of the three 46-to 52-year-old natural Queycus mongojica stands were investigated in Namsan Park at Seoul. Total above- and belowground biomass including understory vegetation for the three stands ranged from 14776t1ha to 278.48t/ha and total net production ranged from 6.96t/ha/yr to 11.11t/yr. Understory vegetation biomass for the three stands ranged from $0.14\%\;to\;1.14\%$ of total biomass. Biomass accumulation ratio for the three stands ranged from 20.72 to 25.07 and net assimilation ratio as an index of foliage photosynthetic efficiency ranged from 2.79 to 3.34. Net production and net assimilation ratio of this study stands which were located in Namsan Park of central Seoul were low compared to the natural Quercus mongojica forests in other districts in Korea.

Study on the by-catch prevention device of spring frame net trap for conger eel, Conger myriaster (붕장어 그물통발의 혼획 방지기구 개발에 관한 기초적 연구)

  • Kim, Wook-Sung;Lee, Ju-Hee;Kwon, Byeong-Guk;Yoo, Jae-Bum;Kim, Bu-Yeung;Kim, Byung-Soo;Lee, Hye-Ok;Cho, Young-Bok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.42 no.1
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    • pp.1-10
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    • 2006
  • Present study was conducted to improve the spring frame net trap for conger eel, Conger myriaster which prevents by-catch and protects immature fish. A series of comparative fishing experiment was carried out in water off the south-east coast of Korea from Nov. 2004 to Jul. 2005. And analyzed the amount of catch, by-catch rate, and CPUE, etc. of experimental traps which were the spring frame net traps, sorted four types of flappers. And the compared gear was a plastic conger eel pot. The conclusions were as follows. By-catch rates of spring frame net trap with the compressed flapper bound by nylon mono-filament was about 0-3%. CPUE of spring frame net trap with the compressed flapper was about 50-60% lower than that of traditional and plastic pot. And in case of conger eel that the total length is over 350mm, CPUE was little different on each type of flapper of every mesh size.

Operational Strategy of Anaerobic Digesters Considering Energy Balance (에너지수지를 고려한 혐기성소화시설의 운영방안)

  • Hong, Seong-Gu;Kwun, Soon-Kuk
    • Journal of The Korean Society of Agricultural Engineers
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    • v.50 no.4
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    • pp.59-66
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    • 2008
  • Anaerobic digestion system is getting more attractive in that it produces biogas in the process of organic waste stabilization. Net energy production is important when biogas production is concerned. In this study, net energy production was evaluated with respect to biogas production and heat losses in a hypothetical digester. Under the condition of digester operation with slurry inflow of 5% of TS, additional fuel is required to maintain digester temperature during the winder season. Substrate therefore, needs to have higher VS contents through co-digestion of silage or food waste that has greater values of methane production rate. Heating input slurry is important in cold season, which covers over 80% of heating requirement. Heat recovery from digestate is valuable to reduce the use of biogas for heating. It seems desirable to minimize slurry inflow when temperature is very low. Psychrophilic digestion may be a feasible option for reducing heating requirement.

Simulation of fish reaction against cage net with an individual fish behaviour model (개체기반 어군행동모델을 이용한 가두리망 내의 양식 어류의 유영행동 시뮬레이션)

  • Hwang, Bo-Kyu;Shin, Hyeon-Ok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.47 no.4
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    • pp.419-427
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    • 2011
  • Simulation technique for the fish behavior was applied to estimate fish school movement in the cage net. Individual-based fish behavior model (Huth and Wessel, 1991) was evaluated in a free area to understand the characteristics for the model, and the movement in the cage net was simulated by defining the fish reaction against the displacement of cage net. As a result, the distance to the net was not considerably changed and the space among fishes in cage net was slightly decreased by reducing the net space. Swimming area was, however, significantly affected by changing the net space and the relationship between swimming area and net displacement was theoretically estimated as y=-0.21x+1.02 ($R^2$=0.96). these results leads the conclusion that individual-based model was appropriated to describe the fish school reaction in the cage net and be able to use for evaluating the influence on cultured fish.