• 공업화학
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• 제30권3호
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• pp.337-344
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• 2019

본 연구에서는 금은화와 회화나무꽃으로부터 항산화성분을 추출하는 용매추출공정의 최적화를 위해 반응표면분석법 중 중심합성계획모델을 이용하였다. 반응표면분석법의 반응치로는 추출수율과 DPPH 라디칼소거활성을 설정하였고, 독립변수로는 추출시간, 주정/초순수 부피비, 추출온도 등을 설정하였다. 중심합성계획모델로 최적화과정을 수행한 결과 금은화의 경우 최적조건은 추출시간(2.08 h), 주정/초순수의 부피비(41.53 vol.%), 추출온도($55.08^{\circ}C$)이었으며, 이 때 수율(37.38 wt.%), DPPH 라디칼소거활성(40.37%) 값을 나타내었다. 또한 회화나무꽃의 경우 추출시간(2.13 h), 주정/초순수의 부피비(62.89 vol.%), 추출온도($50.42^{\circ}C$)에서 개별 최대값인 수율(35.43 wt.%), DPPH 라디칼소거활성(55.27%) 값을 나타내었다.

• 한국산학기술학회논문지
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• 제20권6호
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• pp.557-564
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• 2019

매입형 영구자석 동기전동기(IPMSM : Interior Permanent Magnet Synchronous Motor, 이하 IPMSM)의 회전자 자석의 크기 및 위치와 고정자 슬롯의 크기는 출력 토크 및 토크 리플률 특성에 영향을 준다. 본 논문은 반응표면분석법(RSM : Response Surface Methodology, 이하 RSM)을 이용한 IPMSM의 토크와 토크 리플률(ripplerate) 향상을 위한 최적설계 방법에 대해 다룬다. 토크 출력과 토크 리플률에 영향을 주는 설계변수에 대하여 Plackett-Burmann(PB, 이하 PB)의 민감도 분석을 통해 토크 출력 및 토크 리플 두 가지 목적함수에 영향이 큰 설계변수를 도출하였다. 도출된 목적함수로부터 2차 설계변수를 선정하였으며 중심합성계획법(CCD : Central Composite Design, 이하 CCD)에 따른 실험계획표 정의 및 해석결과를 통해 RSM의 2차 회귀모형 함수를 추정하였다. 2차 회귀모형함수는 분산분석표(ANOVA table)를 활용한 검증 기준을 통해 신뢰성을 가짐을 확인하였다. 실험계획표에 따른 해석은 유한요소법(FEM : Finite Element Method, 이하 FEM) 해석 소프트웨어인 JMAG을 통하여 실험 결과를 확인하였다. 최적화된 최종 설계변수를 적용한 IPMSM의 최적설계 결과는 토크와 토크 리플률을 모두 고려할 경우, 토크 출력은 11.5 % 증가하였으며 토크 리플률은 9.1 % 감소하였다.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1995년도 춘계공동학술대회논문집; 전남대학교; 28-29 Apr. 1995
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• pp.787-796
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• 1995

A man model is a useful design tool for the evaluation of man machine systems and products. An arm reach trajectory prediction for such a model will be specifically useful to present human activities and, consequently, could increase the accuracy and reality of the evaluation. In this study, a three-dimensional reach trajectory prediction model was developed using an inverse kinematics technique. The upper body was modeled as a four link open kinematic chain with seven degrees of freedom. The Resolved Motion Method used for the robot kinematics problem was used to predict the joint movements. The cost function of the perceived discomfort developed using the central composite design was also used as a performance function. This model predicts the posture by moving the joints to minimize the discomfort on the constraint of the end effector velocity directed to a target point. The results of the pairwise t-test showed that all the joint coordinates except the shoulder joint's showed statistically no differences at .alpha. = 0.01. The reach trajectory prediction model developed in this study was found to accurately simulate human arm reach trajectory and the model will help understand the human arm reach movement.

• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.110-117
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• 2008

Three kinds of prenylated flavonols, icariside I, icariside II, and icaritin, were isolated from an icariin hydrolysate and their effects on melanogenesis evaluated based on mushroom tyrosinase inhibition and quantifying the melanin contents in melanocytes. Although none of the compounds had an effect on tyrosinase activity, icariside II and icaritin both effectively inhibited the melanin contents with an $IC_{50}$ of 10.53 and $11.13{\mu}M$, respectively. Whereas icariside II was obtained from a reaction with ${\beta}$-glucosidase and cellulase, the icariin was not completely converted into icariside II. Thus, for the high-purity production of icariside II, the reaction was optimized using the response surface methodology, where an enzyme concentration of 5.0mg/ml, pH 7, $37.5^{\circ}C$, and 8 h reaction time were selected as the central conditions for the central composite design (CCD) for the enzymatic hydrolysis of icariin into icariside II using cellulase. Empirical models were developed to describe the relationships between the operating factors and the response (icariside II yield). A statistical analysis indicated that all four factors had a significant effect (p<0.01) on the icariside II production. The coefficient of determination $(R^2)$ was good for the model (0.9853), and the optimum production conditions for icariside II was an enzyme concentration of 7.5mg/ml, pH 5, $50^{\circ}C$, and 12 h reaction time. A good agreement between the predicted and experimental data under the designed optimal conditions confirmed the usefulness of the model. A laboratory pilot scale was also successful.

• Korean Chemical Engineering Research
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• 제53권2호
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• pp.199-204
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• 2015

지방산 생산을 위한 돈지의 아임계수 가수분해 공정을 최적화하기 위하여 17-run 중심합성법(central composite design)에 기초한 반응표면법(response surface methodology)이 사용되었다. 반응 온도, 오일 대비 물의 몰 비, 반응 시간과 같은 변수 및 이들의 상관관계가 지방산 함량에 미치는 영향을 조사하였으며, 지방산 함량을 예측하기 위하여 2차 다항 회귀방정식이 제안되었다. 최대 지방산 함량을 얻을 수 있는 반응 조건은 $288.5^{\circ}C$, 39.5몰 비, 29.5분이었으며, 이 조건에서의 예측 및 실제 지방산 함량은 각각 97.06% 및 96.99%였다.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.197-201
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• 2005

A novel chitinase-producing bacterial strain of Pantoea dispersa was isolated from the sea near Bhavnagar, India for efficient disposal of chitinous waste from the seafood processing industry. The medium components were optimized by using a cubic model in the central composite design for increasing chitinase production. The optimal concentrations for higher production of chitinase were (g l-1) chitin, 10.0; urea, 0.35; MgSO4 7H2O, 0.08, and CaCl2, 0.15. Here, peptone (0.05 g l-1) was used as a constant variant in all trials. Using a statistical optimization method, the chitinase production was found to increase from 108 to 486.4 units ml-1. Chitin was prepared from the crustacean waste, and Fourier Transform Infrared (FTIR) Spectroscopy was used to characterize the isolated chitin. Chitinous waste degradation was studied in terms of chitinase production.

• 한국생산제조학회지
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• 제22권2호
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• pp.241-247
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• 2013

The doctor blade is equipped in a toner cartridge and is a device to maintain the uniform thickness of a toner by controlling the pressure on the developing roller. The contact pressure between the developing roller and the doctor blade is one of the significant factors for image quality and durability of toner cartridge. The purpose of this study is to develop approximation model in order to minimize the time and cost which are needed much required in making optimal design of the doctor blade. Central composite design was used for the design of experiment and response surface design was used for approximation. The data for contact pressure were acquired through finite element analysis and data of image density and toner weight were acquired through experiment. The approximation model developed in this study has presented very high fitness.

• 한국기계가공학회지
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• 제12권2호
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• pp.68-74
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• 2013

In this paper, an average surface roughness, $R_a$, was measured by optical measurement and its mathematical model according to spindle speed and feedrate was obtained by least square method. Also, its result is compared and investigated with real measured average surface roughness. The optical measurement of surface roughness is performed by CLSM(confocal laser scanning microscope) and the captured HEI(height encoded image) data is used as an original data for the generation of average surface roughness and its mathematical plane or contour surface of surface roughness. Using this polynomial model with two independent variables, the behavior of an average surface roughness is investigated and analyzed with an experimental modeling of least square algorithm. And it can be used for the prediction of $R_a$ in different condition of machining.

• 대한환경공학회지
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• 제37권6호
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• pp.357-362
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• 2015

새로운 형태의 $TiO_2$가 합성된 코코넛 껍질 분말 복합체를 제조하기 위해 솔-젤 합성법과 열처리를 사용하였고, 제조된 TCSPC는 MB를 대상으로 제거효율을 평가하였다. TCSPC를 제조하기 위한 최적의 조건은 반응표면분석법의 중심합성설계법을 사용하여 조사하였다. 소성온도가 $400^{\circ}C$에서 $600^{\circ}C$ 증가함에 따라 BET 비표면적은 $254m^2/g$에서 $398m^2/g$로 증가하고 기공용적, 기공률 또한 증가하며, 그 이유는 소성공정 시 발생한 열분해(pyrolysis)에 의해 코코넛 껍질 분말이 가지고 있는 헤미셀룰로우스, 셀룰로우스, 그리고 리그닌과 같은 물질들의 polymerization 반응 때문인 것으로 판단된다. 코코넛 껍질 분말의 양이 10 g에서 20 g으로 증가 할수록 BET 비표면적은 $303m^2/g$에서 $398m^2/g$로 증가하였으며, 30 g으로 증가 시에는 BET 비표면적은 $345m^2/g$으로 감소하는 경향을 나타내었다. Response optimization을 사용하여 얻은 최적의 합성조건은 소성온도 $642^{\circ}C$, 코코넛 껍질 분말 주입량이 22.7 g으로 나타났다.

• 대한기계학회논문집A
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• 제25권12호
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• pp.1960-1965
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• 2001

In the practical design, it is important to extract the design space information of a complex system in order to optimize the design because the design contains huge amount of design conflicts in general. In this research FEA (finite element analysis) has been successfully implemented and integrated with a statistical approach such as DOE (design of experiments) based RSM (response surface model) to optimize the thermal deformation of an automotive disk brake. The DOE is used for exploring the engineer's design space and for building the RSM in order to facilitate the effective solution of multi-objective optimization problems. The RSM is utilized as an efficient means to rapidly model the trade-off among many conflicting goals existed in the FEA applications. To reduce the computational burden associated with the FEA, the second-order regression models are generated to derive the objective functions and constraints. In this approach, the multiple objective functions and constraints represented by RSM are solved using the sequential quadratic programming to archive the optimal design of disk brake.