• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.318-322
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• 2004

This study was conducted to derive the regional design rainfall by the regional frequency analysis based on the regionalization of the precipitation. For the estimation of the regional design rain(all, classification of the climatologically and geographically homogeneous regions should be preceded preferentially The optimal regionalization of the precipitation data were classified by the above mentioned conditions for all over the regions except Jeju and Ulleung islands in Korea. Relative root mean square error(RRMSE), relative bias(RBIAS) and relative reduction(RR) in RRMSE for the design rainfall were computed and compared between the regional and at-site frequency analysis. Consequently, optimal design rainfalls following the classified regions and consecutive durations were derived by the regional frequency analysis using GEV distribution which was identified to be more optimal one than the other applied distributions.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.343-346
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• 2005

The isolated strain, SC2-1 was Gram-positive, catalase positive, facultatively anaerobic, oxidase negative, motile and small rods. The strain utilized sucrose, dextrose, fructose, mannitol and maltose as a sole carbon and energy source and sodium chloride required for the bacteria growth. The radical scavenging activity of the culture supernatants was determined by DPPH (1,1-diphenyl-2-picrylhydrazyl) method. This bacterium was identified based on cellular fatty acids analysis and 16S rDNA sequencing then named Exiguobacterium sp. SC2-1. The optimum culture conditions for production of antioxidant were $25^{\circ}C,$ pH 7.8 and NaCl concentration were 4%. The modified optimal medium compositions were maltose 2.5% (w/v), yeast extract 1.5% (w/v) and $KH_2PO_4$ 0.05% (w/v). Free radical scavenging activity of under optimal culture conditions were 93%.

• 한국환경과학회지
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• 제16권11호
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• pp.1247-1255
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• 2007

Soil biofiltration is an environmentally-sound technology for elimination of VOCs, odorous and $NO_X$ compounds from a low concentration, high volume waste gas streams because of its simplicity and cost-effectiveness. This study investigated the optimal mixture fraction of briquet ash, compost, soil and loess for $NO_X$ degradation. Extreme vertices design was used to examine the role of four components on $NO_X$ degradation. Under our experimental conditions, 74.5% of $NO_X$ degradation was observed, using a model mixture(25% briquet ash, 10% compost, 30% soil and 40% loess) containing 100 ppb of NO. It was shown that experimental design analysis could allow selecting optimal conditions in such biodegradation processes in this study.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.51-56
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• 2006

A computer code was developed to simulate both the thermal stresses introduced during the post-filling stage and the in-plane deformation after ejection process by finite element method based on the plane stress theory. The computer simulation was applied to the mold design of a 2 inch light guide plate (LGP) for thin film transistor (TFT)-liquid crystal displays (LCD). With injection molding experiments based on the design of experiments (DOE) technique, the influences of the processing conditions in injection molding on brightness and uniformity of the LGP were investigated, and the optimal processing parameters were selected to increase the brightness and uniformity. The verification experiment showed that the brightness and uniformity of the LGP were increased dramatically under the selected optimal processing conditions.

• 소성∙가공
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• 제11권4호
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• pp.363-370
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• 2002

In this study, an optimal design technique was investigated for determining appropriate dimensions of components of the die set used in the extrusion process. For this, an axi-symmetric elastic finite element program for the analysis of deformation of the shrink fitted die set was developed with the Lagrange multiplier method to implement the constraint condition of shrink fit of stress ring. By coupling the rigid-viscoplastic analysis of extrusion process by CAMPform and elastic analysis of the die set, the optimization study was made by employing optimization program DOT. Considering the various assembly conditions, optimal design was determined for a single stress ring case. It is construed that the proposed design method can be beneficial for improving the tool life of cold extrusion die set at practice.

• 한국공작기계학회논문집
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• 제12권2호
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• pp.9-16
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• 2003

A strategy of the optimal shape design with FEA(Finite Element Analysis) for 2-D structure is proposed by comparing subproblem approximation method with first order approximation method. A cantilever beam with two different loading conditions, a concentrated load and an evenly distribute load, and truss structure with a concentrated loading condition are implemented to optimize the shape. It gives a good design strategy on the optimal truss structure as well as the optimal cantilever beam shape. It is found that the convergence is quickly finished with the iteration number below ten. Optimized shapes of cantilever beam and truss structure are shown with stress contour plot by the results of the subproblem approximation method and the first order approximation methd.

• 한국공작기계학회논문집
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• 제13권4호
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• pp.1-8
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• 2004

Various controllable parameters of an experiment have influence on grinding process. In order to get good products with a high quality, these parameters should be considered whether each parameter has relations to the quality. This paper describes the use of the design of experiments to minimize geometric error in surface grinding. Controllable parameters for the design of experiments were selected as spindle speed, table speed, depth of cut and grain size. From the experimental results, a degree of influence between these parameters and the geometric error was evaluated. An optimal set of grinding conditions was obtained by means of analysis of variance(ANOVA).

• 소성∙가공
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• 제13권3호
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• pp.230-235
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• 2004

A new design based on the appropriate geometry of molded part and type of runner system under the optimal processing conditions was proposed to minimize the micro weld lines on the sub deco surface molded by two shot molding. Theoretical and experimental studies were conducted to examine the cause of the weld lines during the overmolding process in two shot molding. Various dimensions and geometries of substrate$(1^{st}shot)$ and the wall thickness of overmold$(2^{nd}shot)$ have been proposed to avoid the weld lines which are the most inevitable appearance defects occurred on the sub deco. The each design proposal was analyzed by mold flow analysis after part modeling. The analysis results were compared with molded part from mass production tool. It could be seen that from the analysis that the proper geometry of plastic part and type of runner system considering pressure drop under the optimal processing conditions were the most influential factors to avoid weld lines occured on the sub deco.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.364-367
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• 2005

This study investigated the production of antioxidant from Actinomyces culture supernatant. For the research of the natural marine antioxidant, several bacteria were isolated from the coast of Je-ju in Korea. An actinomycetes strains, S-1 was identified to a genus level 16S ribosomal DNA sequence and fatty acid analysis. From these results and other characteristics described in the Bergey's Manual, this strain was identificated as a Nocardiopsis dassonvillei. Strain S-1 showed high activity of 1,1-diphenyl-2-prcrylhydrazyl radical scavenging. The hydroxyl radical scavenging ability of Nocardiopsis sp. S-1 supernatant was 53%. Nutritional and cultural conditions for the production of antioxidant by this organism under shake-flask conditions have optimized. Similary initial medium pH 7.6, incubation temperature of $25^{\cicr}C$, sodium chloride concentration 2.5 and incubation time of 8 day were found to be optimal.

• Journal of Ginseng Research
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• 제40권3호
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• pp.229-236
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• 2016

Background: Extraction conditions greatly affect composition, as well as biological activity. Therefore, optimization is essential for maximum efficacy. Methods: Korean Red Ginseng (KRG) was extracted under different conditions and antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content evaluated. Optimized extraction conditions were suggested using response surface methodology for maximum antioxidant activity and extraction yield. Results: Analysis of KRG extraction conditions using response surface methodology showed a good fit of experimental data as demonstrated by regression analysis. Among extraction factors, such as extraction solvent and extraction time and temperature, ethanol concentration greatly affected antioxidant activity, extraction yield, and ginsenoside Rg1 and phenolic content. The optimal conditions for maximum antioxidant activity and extraction yield were an ethanol concentration of 48.8%, an extraction time 73.3 min, and an extraction temperature of $90^{\circ}C$. The antioxidant activity and extraction yield under optimal conditions were 43.7% and 23.2% of dried KRG, respectively. Conclusion: Ethanol concentration is an important extraction factor for KRG antioxidant activity and extraction yield. Optimized extraction conditions provide useful economic advantages in KRG development for functional products.