• Journal of the Korean Data and Information Science Society
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• v.24 no.1
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• pp.53-62
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• 2013

Currently we have 11 climatological stations registered in World Meteorological Organization. Geographically, these stations are unevenly distributed in Korea and are mainly located on seaside. Therefore station's density analysis should be performed to produce the high-quality climatological data. Using the correlation integral method, the density of climatological stations can be measured by the estimation of fractal dimension. In this study, new climatological stations having the higher fractal dimension were selected. Sequential or simultaneous selection method were carried out until 3 new stations were selected based on the fractal dimension.

• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.149-158
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• 2006

A review has been made on what kind of method can be applied to predict the dynamic derivatives of the separated PLF(Payload Fairing) halves of a launch vehicle in consideration of technology and budget. An optimal approach is selected considering the geometric characteristics of the PLF halves, the aerodynamic conditions and the required accuracy. The time history of aerodynamic force/moment coefficients are obtained for the forced harmonic motions by solving the unsteady Euler equations derived with respect to the inertial reference frame. and the dynamic derivatives are deduced by integration of the aerodynamic coefficients for one period. In this research, the dynamic derivatives are presented for 0.6$\leq$ M $\leq$2.0, $-180^{\circ}$ $\leq$$\alpha$ $\leq$$180^{\circ}$ and $-90 ^{\circ}$$\leq$$\beta$$\leq$$90 ^{\circ}$.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.20-25
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• 2014

There are several severe problems for LED device, the next generation's economy green lighting: as the temperature increases, the lamp efficiency decreases; if the temperature is over $80^{\circ}C$, the lifetime of lighting decreases; Red Shift phenomenon that wavelength of spectrum line moves toward long wavelength occurs; and optical power decreases as $T_j$ increases. Thus, Heat sink design that can minimize the heat of LED device is currently in progress. While the thermal resistance of COB Type LED was reduced by direct coupling of LED chip to the board, residential 13.5W requires Heat sink in order resolve heat issue. This study designed Heat Sink suitable for residential 13.5W COB LED down-light and selected the optimum Fin thickness through flow simulation that packaged the designed Heat Sink and 13.5W COB. And finally it analyzed and evaluated the thermal modes using contacting thermometer.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.485-490
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• 2011

Tetrafluoromethane($CF_4$) has been used as etching and chamber cleaning gases for semiconductor manufacturing processes. These gases need to be removed efficiently because of their strong absorption of infrared radiation and long atmospheric lifetime which causes the global warming effect. We have developed a waterjet gliding arc plasma system in which plasma is combined with waterjet and investigated optimum operating conditions for efficient $CF_4$ destruction through enlarging discharge region and producing large amount of OH radicals. The operating conditions are waterjet flow rate, initial $CF_4$ concentration, total gas flow rate, specific energy input. Through the parametric studies, the highest $CF_4$ destruction of 97% was achieved at 2.2% $CF_4$, 7.2 kJ/L SEI, 9 L/min total gas flow rate and 25.5 mL/min waterjet flow rate.

• KSBB Journal
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• v.16 no.4
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• pp.430-434
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• 2001

Microorganisms of livestock wastewater were microscopically examined to identify bacillus types with optimal absorbance at 630 nm. Growth cuties of microorganisms at various levels of livestock wastewater (5, 10, 20, 30, 40, 50%) and different temperatures (20$\^{C}$ , 37$\^{C}$) were prepared to determine dilution at which microorganisms did not grow within 1 hour of inoculation, regardless of levels and temperatures. Heat treatment of livestock wastewater at 10 0$\^{C}$ for 2 minutes was good enough to inhibit the growth of microorganisms at 20$\^{C}$ and 37$\^{C}$. A good linear relationship was obtained between levels of livestock wastewater and absorbance at 630 nm (R=98.88%) and dry cell weight (98.98%). The dry cell weight of microorganisms in livestock wastewater was 0.375 g/L.

• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.396-399
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• 2007

Organic residue and carbonized solid producing from the thermal degradation gave a influence on oil conversion, formation of styrene and side products such as ${\alpha}-methyl$ styrene, ethyl benzene, dimer. Thus, new reaction system using wetted-wall type reactor was proposed and examined on influence of various parameters such as reaction temperature, feeding rate and removal velocity of formed vapor. Optimum condition were obtained from continuous thermal degradation using wetted-wall type reactor and styrene was continuously obtained as the yield up 65%.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.3
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• pp.360-365
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• 2003

In this paper, GMDH(Croup Method of Data Handling) algorithm which is proved to be more excellent in efficiency and accuracy of practical use of data is applied to electric power demand forecasting. As a result, it became much easier to make a choice of input data and make an exact prediction based on a lot of data. Also, we considered both economy factors(GDP, export, import, number of employee, number of economically active population and consumption of oil) and climate factors(average temperature) when forecasting. We assumed target forecast period from first quarter 1999 to first quarter 2001, and suggested more accurate forecasting method of electric power demand by using 3-step computer simulation processes(first process for selecting optimum input period, second for analyzing time relation of input data and forecast value, and third for optimizing input data) for improvement of forecast precision. The proposed method can get 0.96 percent of mean error rate at target forecast period.

• Korean Journal of Agricultural Science
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• v.14 no.1
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• pp.144-155
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• 1987

A potent fungus producing milk clotting enzyme with fairly weak proteolytic activity was isolated from various soil and sewage, which the selected strain, SA-101, was identified as Mucor sp. with microbiological characteristics. Its milk clotting enzyme production was maximized when grown on 10g of wheat bran media added to 8ml of tap water containing 0.1M HCl for 60hrs at $30^{\circ}C$. This enzyme production was stimulated by addition of 6% lactose, 0.05% NaCl and reached a maximal level of 9810 unit/g wheat bran. The crude enzyme product could be produced effectively by salting out with ammonium sulfate fractionation and lyophilization. The ratio of milk clotting activity to proteolytic activity of crude enzyme product was lower than Hansen rennet, but resembled to Meito rennet. The optimal temperature of milk clotting activity of crude enzyme product was abound $60^{\circ}C$ on a substrate of 10% reconstituted skim milk containing 1/100M $CaCl_2$.

• Korean Journal of Agricultural Science
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• v.21 no.1
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• pp.11-21
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• 1994

The halophile, Micrococcus sp. which produces RNase was isolated from salted and fermented food. The optimum growth condition of the Micrococcus sp. in pH 7.0 of complex medium containing 2M NaCl, and at $35^{\circ}C$. Optimum condition for enzyme production by this strain was when it was grown in the CM medium, containing 2% yeast extract, 1.5% casamino acid and 2M NaCl in the initial pH 8.5 for 2 days. The maximal RNase activity was observed at pH 8.0 and $55^{\circ}C$. The Km value for RNA was determined to be 5mg/ml by Lineweaver-Burk plot. The RNase activity in the absence of NaCl was maximum, but it was completely lost by adding of 1.25M NaCl and it was increased above 1.25M to 2.5M NaCl. When 2.5M NaCl was added, the activity of RNase showed 45% of maximum value.

• Spatial Information Research
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• v.14 no.3 s.38
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• pp.271-284
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• 2006

This study suggests the adjustment method of cadastral non-coincidence using spatial data referenced digital cadastral map and a present state. In designing the methodology, we should introduce the semi-automatic method for guaranteeing the stability and the accuracy at the arrangement of cadastral non-coincidence based on some cadastral specialist. This study could mainly show you rotation type, bias type, and rotation/bias type among cadastral non-coincidence types. We selected the matching reference point through the prototype system which automatically arranges in the study area. And then, we analysis the optimum rotation ratio(-0.4%). Finally, this paper show you calibrating cadastral non-coincidence using the rotation ratio. The methodology of this study has a limitation for arranging in case of cadastral non-coincidence by the area variation and some irregular types with unknown reason. Therefore, this case should be surveyed in direct method.