• The Journal of Engineering Geology
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• v.20 no.1
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• pp.61-70
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• 2010

In case of groundwater recharge estimation using water table fluctuation method, specific yield affects the accuracy and confidence level of recharge rate. Nevertheless, there have been few studies on the method for the accurate estimation of specific yield in Korea. Specific yield estimated from the relationship between rainfall and groundwater levels is reasonable compared to the other methods. However, lots of factors such as artificial pumping, evapotranspiration by the plants, and a sudden increase in water levels by a heavy rainfall can affect the pattern of groundwater levels' fluctuation and make an over-estimated or under-estimated specific yield. This study obtained a reasonable specific yield by using a daily or 12 hourly average of rainfall and groundwater levels measured in a dry season.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.311-314
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• 2003

This research recognized change of the specific yield(Sy) by groundwater level in small size tube well of the farm village area. The result research basin aquifer could quality that the specific yield according to geological quality of aquifer changes showed value of $0.0004{\sim}0.081$ extents according to groundwater level decline.

• Biotechnology and Bioprocess Engineering:BBE
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• v.1 no.1
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• pp.22-25
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• 1996

An Exponetial feeding strategy has been frequently used in fed-batch fermentation of recombinant E. coli. In this feeding scheme, growth yield and initial cell concentration, which can be erroneously determined, are needed to calculate the feed rate for controlling specific growth rate at the set point. The effect of the incorrect growth yield and initial cell concentration on the control of the specific growth rate was theoretically analyzed. Insignificance of the correctness of those parameters for the control of the specific growth rate was shown theoretically and experimentally.

• Agricultural and Biosystems Engineering
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• v.7 no.1
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• pp.18-26
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• 2006

In-field site-specific nitrogen (N) management increases crop yield, reduces N application to minimize the risk of nitrate contamination of ground water, and thus reduces farming cost. Real-time N sensing and fertilization is required for efficient N management. An 'on-the-go' site-specific N management system was developed and evaluated for the supplemental N application to com (Zea mays L.). This real-time N sensing and fertilization system monitored and assessed N fertilization needs using a vision-based spectral sensor and controlled the appropriate variable N rate according to N deficiency level estimated from spectral signature of crop canopies. Sensor inputs included ambient illumination, camera parameters, and image histogram of three spectral regions (red, green, and near-infrared). The real-time sensor-based supplemental N treatment improved crop N status and increased yield over most plots. The largest yield increase was achieved in plots with low initial N treatment combined with supplemental variable-rate application. Yield data for plots where N was applied the latest in the season resulted in a reduced impact on supplemental N. For plots with no supplemental N application, yield increased gradually with initial N treatment, but any N application more than 101 kg/ha had minimal impact on yield.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.23-30
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• 2000

A calculation technique which estimates natural recharge was proposed and prepared with the existing techniques. And the necessity to obtain representative averages of 'specific yield' was discussed.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.1
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• pp.67-71
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• 2004

Ten improved mulberry varieties (Vl, C1730, C2016, C2017, Anantha, RFS-175, Thallaghatapura, Vishala, S1 and S1635) were evaluated through enzyme assay and estimation of soluble protein content followed by regression analysis, grown under irrigated conditions in the alluvial soils of Gangetic plains of West Bengal in India for five successive crops in a year, The nitrate reductase (EC No. 1.6.6.1) activity (NRA, $\mu$mol N $O_2$- $h^{-1}$ $g^{-1}$ fr, wt.), total soluble protein (mg $g^{-1}$ fr, wt.) was estimated which showed to vary significantly in the tested varieties. In addition to these, the other parameters like unit leaf fresh and dry weight (g), moisture ％, unit leaf area ($\textrm{cm}^2$), specific leaf weight (g c $m^{-2}$ ), total soluble sugar (mg $g^{-1}$ fr, wt.), leaf yield/plant (kg), shoot yield/plant (kg) and net photosynthetic rate (NPR, $\mu$㏖ $m^{2}$ $s^{-1}$ ) were also studied which showed to vary significantly in tested varieties. Among them, S1635, haying higher NRA (13.25 $\mu$㏖ N $O_2$- $h^{-l}$ $g^{-1}$ fr, wt.), total soluble protein (39.63mg $g^{-1}$ fr, wt.), NPR(16.66 $\mu$㏖ $m^{-2}$ $s^{-1}$ ), total soluble sugar (48.44 mg $g^{-1}$ fr. wt.), leaf yield/plant (0.689 kg) and shoot yield/plant (1.135 kg) showed its superiority over other tested varieties. Regression and correlation coefficients were analysed, and a strong positive correlation was found between NRA ＆ total soluble protein, NRA ＆ NPR, NRA ＆ total soluble sugar, NRA af unit leaf weight, NRA ＆ specific leaf weight, NRA ＆ leaf yield/plant, NRA ＆ shoot yield/plant, NPR ＆ leaf yield and NPR ＆ specific leaf weight.t.

• Economic and Environmental Geology
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• v.41 no.1
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• pp.115-131
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• 2008

The aim of this study is to analyze relationships between topography/geology which affects physically groundwater regime and groundwater yield properties in Pohang City using Geographic Information System (GIS). For the purpose, topographic factors such as ground elevation, ground elevation difference, ground slope, and ground regional slope, and hydrogeologic unit, and groundwater yield properties factors such as transmissivity, specific capacity, and well yield, were constructed to spatial data base. Then the relationships between topography, geology and groundwater yield properties were analyzed quantitatively using GIS overlay technique. As the results, ground-water yield of unconsolidated sediments and porous volcanic rocks is the highest among the hydrogeologic units of study area, and clastic sedimentary rock is the lowest. There are positive relationship between the elevation and elevation difference and the groundwater yield properties and negative relationship between the topographic slope and the groundwater yield properties.

• Journal of Korea Water Resources Association
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• v.37 no.8
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• pp.687-693
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• 2004

The MODFLOW simulated results with varying input parameter values were compared and analyzed. To understand the relative importance of the input parameters, sensitivity analysis was carried out. The amount of sustainable yield was analyzed with respect to the hydraulic conductivity, specific yield, specific storage, aquifer thickness and the distance of the wells from the river. The results of sensitivity analysis showed that inflow from the river and the aquifer storage were sensitive to the specific yield and aquifer thickness. Sustainable yield was sensitive to the hydraulic conductivity and aquifer thickness. The results of this study can be used as a basic information for groundwater development and management plannings considering regional characteristics.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.313-316
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• 2000

The effects of initial sugar concentration and the various nitrogen sources on the fermentation characteristics of Thraustochytrium aureum were investigated. The sugar conversion ratios decrease with increase in the initial sugar concentration regardless of the kinds of nitrogen sources. The specific growth rate, the biomass yield, and the DHA yield also decreased but approached constant values higher than the concentration of 30g/L. The sugar conversion ratios and the specific growth rate showed the highest values in case of using the yeast extract as nitrogen source. It was difficult to conclude that the variation of nitrogen source had some effects on the biomass yield. However, the initial sugar concentration had a rather effects on the biomass yield for the sugar concentration of 40 g/L showed 0.27. The nitrogen source that showed the greatest yield of DHA was sodium glutamate.

• Journal of Environmental Science International
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• v.25 no.10
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• pp.1433-1444
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• 2016

South Korea is a maritime nation, surrounded by water on three sides; hence, it is important to preserve in a sustainable manner. Most areas, especially those bordering the East Sea, have been suffering from severe coastal erosion. Information on the sediment yield of a river basin is an important requirement for water resources development and management. In Korea, data on suspended sediment yield are limited owing to a lack of logistic support for systematic sediment sampling activities. This paper presents an integrated approach to estimate the sediment yield for ungauged coastal basins by using a soil erosion model and a sediment delivery rate model in a geographic information system (GIS)-based platform. For applying the sediment yield model, a basin specific parameter was validated on the basis of field data, that, ranging from 0.6 to 1.2 for the 19 gauging stations. The calculated specific sediment yield ranged from 17 to $181t/km^2.yr$ in the various basin sizes of Korea. We obtained reasonable sediment yield values when comparing the measured data trends around the world with those in Korean basins.