• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.6
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• pp.49-55
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• 2004

The increase of computing power makes stochastic optimization algorithms available in structural design. One of the stochastic algorithms, simulated annealing algorithm, has been applied to various structural optimization problems. By applying several cooling schedules such as simulated annealing (SA), Boltzmann annealing (BA), fast annealing (FA) and adaptive simulated annealing (ASA), truss structures are optimized to improve the quality of objective functions and reduce the number of function evaluations. In this paper, many cooling parameters have been applied to the cooling schedule of ASA. The influence of cooling parameters is investigated to find the rules of thumb for using ASA. Tn addition, the cooling schedule combined with BA and ASA is applied to the optimization of ten bar-truss and twenty five bar-truss structure.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1322-1326
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• 2010

확산-유추 지형학적 순간단위도는 통계물리적인 모형으로 이론적 물리적으로 뛰어난 모형임에도 불구하고 유역의 동적 매개변수인 특성유속과 확산계수의 산정이 어려워 실제적인 사용이 제한되어 왔다. 이러한 난제를 해결하기 위하여 본 연구에서는 금강수계의 보청천 산성유역을 대상으로 전역최적화 기법인 SCE-UA를 이용하여 확산-유추 지형학적 순간단위도 모형의 동적 매개변수 산정하였으며, 모형의 재현성을 3개의 수문사상을 이용하여 검토하였다. 매개변수의 최적화 결과 차수 단계별 특성유속 및 확산계수의 증감은 변동을 보이지만, 전체적인 경향성은 특성유속의 경우 하천차수가 커질수록, 즉 하류방향에 대해 증가 경향을 나타내며, 반대로 확산계수는 감소되는 경향을 나타냈다. 본 연구에서 적용한 최적화 방법에 향후 지체시간, 분산 및 왜곡도 등의 통계적인 제약조건과 동적 매개변수의 공간적 변화 등의 물리적인 의미를 갖는 제약조건 등이 결합된다면 좀 더 발전된 모형으로 개선될 수 있을 것으로 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.781-788
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• 2008

This study shows how to find out optimum co-substrate conditions and continuous operating parameters for maximum acidification of three different organic wastes - livestock wastewater, sewage sludge and food waste. Design of experiments and statistical analysis were revealed as appropriate optimization schemes in this study. Analyses of data obtained from batch tests demonstrated the optimum substrate mixing ratio, which was determined by maximum total volatile fatty acids(TVFA) increase and soluble chemical oxygen demand(SCOD) increase simultaneously. Suggested optimum mixing ratio of livestock wastewater, sewage sludge and food waste was 0.4 : 1.0 : 1.1 based on COD, respectively. Response surface methodology(RSM) contributed to find out optimum operating parameter - hydraulic retention time(HRT) and substrate concentration - for the semi-continuous acidogenic fermentation of mixed organic wastes. The optimum condition for maximum TVFA increase was 2 days of HRT and 29,237 mg COD/L. Empirical equations obtained through regression analysis could predict that TVFA increase would be 73%. To confirm the validity of the statistical experimental strategies, a confirmation experiment was conducted under the obtained optimum conditions, and relative error between theoretical and experimental results was within 4%. This result reflects that using statistical and RSM technique can be effectively used for the optimization of real waste treatment processes.

• Bioindustry News
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• v.10 no.1
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• pp.10-14
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• 1997

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.615-619
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• 2019

Statistical design of experiments was performed to optimize MOF-235 synthesis process. Concentrations of terephthalic acid (TPA), iron (III) chloride hexahydrate, N,N-dimethylformamide (DMF) and ethanol were important factors to develop the crystal structure of MOF-235. MOF-235 was synthesized with various concentrations of the listed chemicals above and the crystallinity was measured by XRD. The effect of the composition on the synthesis of MOF-235 was evaluated using a statistical analysis. For the variance analysis using F-test, the concentration of ethanol showed the greatest effect on the crystallinity and TPA the least influential. A regression model for predicting the crystallinity of MOF-235 was derived and the prediction results for two synthetic variables were presented using contour plots. Finally, the crystallinity was predicted by a mixture method with $FeCl_3$, ethanol and DMF.

• Journal of Life Science
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• v.21 no.8
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• pp.1083-1093
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• 2011

A microorganism utilizing rice hulls as a substrate for the production of carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus lincheniformis by analyses of its 16S rDNA sequences. The optimal carbon and nitrogen sources for production of CMCase were found to be rice hulls and ammonium nitrate. The optimal conditions for cell growth and the production of CMCase by B. lincheniformis LBH-52 were investigated using the response surface method (RSM). The analysis of variance (ANOVA) of results from central composite design (CCD) indicated that a highly significant factor ("probe>F" less than 0.0001) for cell growth was rice hulls, whereas those for production of CMCase were rice hulls and initial pH of the medium. The optimal conditions of rice hulls, ammonium nitrate, initial pH, and temperature for cell growth extracted by Design Expert Software were 48.7 g/l, 1.8 g/l, 6.6, and 35.7$^{\circ}C$, respectively, whereas those for the production of CMCase were 43.2 g/l, 1.1 g/l, 6.8, and 35.7$^{\circ}C$. The maximal production of CMCase by B. lincheniformis LBH-52 from rice hulls under optimized conditions was 79.6 U/ml in a 7 l bioreactor. In this study, rice hulls and ammonium nitrate were developed to be substrates for the production of CMCase by a newly isolated marine microorganism, and the time for production of CMCase was reduced to 3 days using a bacterial strain with submerged fermentation.

• KSBB Journal
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• v.20 no.3
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• pp.215-219
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• 2005

Production of alkaline pretense by Bacillus clausii I-52 was optimized by experimental design methods. Among 7 medium components, three (wheat flour, sodium citrate, sodium carbonate) were selected as components affecting the pretense activity significantly by Plackett-Burman methods. Furthermore the ranges of effective concentrations were determined by Box-Behnken methods. The objective function describing the alkaline pretense production was obtained and optimum concentration of 3 components was determined by using response-surface methods (RSM). Theoretical maximum production was 74000 U/mL (Wheat flour: 0 g/L, Sodium citrate: 5 g/L, Sodium carbonate: 10 g/L). With the optimized medium composition, 92000 U/mL alkaline protease was produced experimentally, resulting in $90\%$ increase compared to before-optimization production (49000 U/mL).

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1752-1756
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• 2007

정교한 강우-유출 모의를 위해서는 적절한 매개변수의 추정이 필수적이며, 매개변수 추정 방법은 시행착오(trial and error)에 의한 수동보정법과 최적화방법을 사용한 자동보정법으로 구분할 수 있다. 모형의 매개변수의 수가 많은 경우 수동보정법에 의한 매개변수 추정은 매우 어렵다. 자동 보정법에 사용되는 최적화방법은 Rosenbrock 알고리즘, patten search, 컴플렉스(complex) 방법, Powell 방법 등과 같은 지역최적화 방법과 전역최적화 방법으로 나눌 수 있다. 그러나 기존 방법론들은 매개변수의 최적화를 추적하기 위한 알고리즘이 대부분이며 이들 매개변수에 관련된 불확실성을 평가하는데는 미흡한 단접이 있다. 이러한 점에서 본 연구에서는 강우-유출모형의 매개변수 추정에 있어서 불확실성을 평가할 수 있는 새로운 방법론을 검토하고자 한다. 매개변수와 관련된 불확실성을 평가하기 위한 방법은 여러 가지가 있으나 통계적으로 매우 우수한 능력을 보이는 Hierarchical Bayesian 알고리즘을 Probability-Distributed 강우-유출 모형에 적용하였다. 본 방법론은 최적화와 동시에 각 매개변수에 관련된 사후분포(posterior distribution)의 추정이 가능하므로 모형이 갖는 불확실성을 효과적으로 평가할 수 있다. 따라서, 수자원 관리에 있어서 불확실성을 고려할 수 있으므로 보다 수리수문학적 위험도를 저감할 수 있을 것으로 판단된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.8B
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• pp.691-698
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• 2003

Throughput response characteristics depending on the network bandwidth allocation need to be modeled to devise adaptive control mechanism to support QoS of the network. Thus, two models are proposed in this study. The first one is a dynamic system model and the other one is a stochastic model. The dynamic system model is developed to represent dynamic characteristics of the network and the stochastic model is developed to represent distribution of measured throughput data. An optimization technique is used for decision of proposed model's factor. The result confirms that the characteristics of proposed models are similar with actual network's characteristics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.4
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• pp.592-601
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• 2015

Rubus coreanus is known as Korean black raspberry, native to Korea, Japan, and China. Preliminary studies evaluating their potential for cancer treatment in mammalian test systems are ongoing. In recent years, interest has been renewed due to their high levels of anthocyanins. Anthocyanins in black raspberry are important due to their potential health benefits as dietary antioxidant, anti-inflammatory compound, and as a chemopreventive agent. In the present study, Saccharomyces cerevisiae BA29 was isolated from black raspberry fruit and fruit juice as a biogenic amine non-producing strain for manufacturing of black raspberry wine, after which we investigated its characteristics: biogenic amine-producing ability, cell growth ability, alcohol-fermentation ability, and resistance to alcohol, glucose, and sulfur dioxide. Based on preliminary experiments, we optimized culture medium compositions for improving dried cell weight of S. cerevisiae BA29 by response surface methodology (RSM) as a statistical method. Design for RSM used a central composite design, and molasses with the industrial applicability was used as a carbon source. Through statistical analysis, we obtained optimum values as follows: molasses 200 g/L, peptone 30 g/L, and yeast extract 40 g/L. For the model verification, we confirmed about 3-fold improvement of dried cell weight from 6.39 to 20.9167 g/L compared to basal yeast peptone dextrose medium. Finally, we manufactured black raspberry wine using S. cerevisiae BA29 and produced alcohol of 20.33%. In conclusion, S. cerevisiae isolated from black raspberry fruit and juices has a great potential in the fermentation of black raspberry wine.