• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.1
• /
• pp.114-120
• /
• 2010

Optimization of the turning process has been concentrated on the selection of the optimal cutting parameters, such as cutting speed, feed rate and depth of cut. However, optimization of the cutting parameters does not necessarily guarantee the maximum profit. For the maximization of the profit, parameters other than cutting parameters have to be taken care of. In this study, 8 price-related parameters were considered to maximize the profit of the product. Regression equations obtained from RSM technique to relate the cutting parameters and maximum cutting volume with a given insert were used. The experiments with four combinations of cutting inserts and material were executed to compare the results that made the profit and cutting volume maximized. The results showed that the cutting parameters for volume and profit maximization were totally different. Contrary to our intuition, global optimization was achieved when the number of inserts change was larger than those for volume maximization. It is attributed to the faster cutting velocity, which decreases processing time and increasing the number of tool used and the total tool changing time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.05a
• /
• pp.404-409
• /
• 2004

A compressor loop pipe is the most important part in a refrigerator from the view of structural vibration and noise. Vibration energy generated from a compressor's inner body is transmitted to the shell and outside through the loop pipe. For this reason it is very important to design a compressor loop pipe. But, for geometrical complexity and dynamic nonlinearity of the loop pipe, analysis and design of the loop pipe is very difficult. So the statistical and experimental methods have to be used for design of this system. The response surface method (RSM) becomes a popular meta-modeling technique f3r the complex system as this loop pipe. As starting point of loop pile's optimization, FEA model and simple experimental model are used instead of the real loop pipe model. After RS model was constructed, using sensitivity-based optimizer performed optimization for the loop pipe. And the moving least square method (MLSM) was applied to reduce the approximation error.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.6
• /
• pp.902-908
• /
• 2018

Optimization of the culture medium to maximize menaquinone-7 (MK-7) production by Bacillus subtilis strain KCTC 12392BP in static culture was carried out using statistical experimental methods, including one factor at a time, fractional factorial design, and response surface methodology (RSM). Maltose (carbon source), tryptone (nitrogen source), and glycerol (activator) were identified as the key medium components for MK-7 synthesis by the fractional factorial design, and were selected for statistical optimization by RSM. The statistical analysis indicated that, in the range that was studied, maltose, tryptone, and glycerol were all critical factors having profound effects on the production of MK-7, with their coefficients for linear and quadratic all significant at the p < 0.05 level. The established model was efficient and feasible, with a determination coefficient ($R^2$) of 0.9419. The predicted concentrations of maltose, tryptone, and glycerol in the optimal medium were determined as 36.78, 62.76, and 58.90 g/l, respectively. In this optimized medium, the maximum yield of MK-7 reached a remarkably high level of $71.95{\pm}1.00{\mu}g/ml$ after 9 days of static fermentation, which further verified the practicability of this optimized strategy.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.2
• /
• pp.211-216
• /
• 2018

This paper presents a numerical optimization technique and switching phase control technique aiming at improvement of efficiency of the low voltage BLDC motor. The optimization technique is performed using the generalized sensitivity technique, response surface method(RSM) and sampling minimization technique. In order to minimize current consumption of the BLDC motor, the switching method of the driving device is optimized using RSM with finite element analysis. The ratings of BLDC motor are 50 W, 24 V, 1200 rpm. As optimizing results, the input current is reduced from 2.78 to 2.51 [A] when the switching phase is shifted by -2.65 [DEG_ELC] at the rated driving speed of 1200 [rpm]. It is confirmed that the proposed method reduces the consuming current of the low voltage BLDC motor through switching phase control method using the numerical optimization method.

• Journal of Power Electronics
• /
• v.15 no.2
• /
• pp.479-486
• /
• 2015

The application of soft-switching techniques is increasing in the DC/DC converter area. It is important to design soft-switching parameters to ensure the converter operates properly and efficiently. An optimized design method is presented in this paper. The objective function is the total power loss of a converter, while the variables are soft-switching parameters and the constraints are the electrical requirements for soft-switching. Firstly, a response surface methodology (RSM) model with a high precision is built, and the rough optimized parameters can be obtained with the help of a genetic algorithm (GA) in the solution space determined by the constraints. Secondly, a re-optimization is conducted with a SPICE model and a GA, and accurate optimized parameters can be obtained. Simulation and experiment results show that the proposed method performs well in terms of a wide adaptability, efficiency, and global optimization.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.8 no.3
• /
• pp.211-220
• /
• 2003

This paper presents an implementation of direct torque control (DTC) of Reluctance Synchronous Motor (RSM) with an efficiency optimization. The equipment circuit in Reluctance Synchronous Motor which consider with iron losses is theoretically analyzed and the optimal current ration between torque current and exiting current analytically derived to drive RSM at maximum efficiency. For RSM, torque dynamics can be maintained even with controlling the flux level because a torque is directly proportional to the stator current unlike induction motor. The experimental results are presented to validate the applicability of the proposed method. The developed control system show high efficiency features with 1.0 Kw RSM having 2.57 ratio of d/q reluctance.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1210-1211
• /
• 2011

The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as PM length, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combination computation of two dimensional (2-D) finite element analysis (FEA) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized to predict the global optimal solution based on the FEA calculated results of the detect forces for different combinations of factors. With the help of the combination computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces.

• Proceedings of the KIEE Conference
• /
• 2004.10a
• /
• pp.123-125
• /
• 2004

This paper presents the application of response surface methodology (RSM) to design optimization for two types of synchronous reluctance motors (SynRMs); one has 12 slots with distributed winding, and the other has 6 slots with concentrated winding, to improve the ratio between torque ripple and average torque. The usefulness of RSM in optimization problem of SynRM is verified as compared with the results of finite element analysis. In the end, the optimized two SynRMs are compared with SynRM currently used in air-conditioning compressor in connection with torque performance and loss.

• Microbiology and Biotechnology Letters
• /
• v.25 no.2
• /
• pp.207-211
• /
• 1997

Media optimization for the production of thermostable protease specifically hydrolyzing defatted soybean meal (DSM) from Bacillus licheniformis NS70 was performed by two methods, one-at-a-time method and response surface methodology (RSM). The best carbon source and nitrogen source for the protease production were lactose and DSM, respectively. The maximum protease production estimated by RSM was 606 U/L at 1.11% lactose and 0.43% DSM, the value of which was nearly consistent to the experimental value of 599 U/L. Yeast extract suppressed the protease production. The medium pH was slightly increased at the beginning stage of fermentation, and it tended to decrease after 8 hours. The optimal pH for the protease production was 7.2 in the batch fermentation.

• Culinary science and hospitality research
• /
• v.23 no.5
• /
• pp.67-76
• /
• 2017

This study investigated the quality characteristics of melon jam with RSM. The melon jam was prepared with 50~65% sugar, 0.5~2.0% pectin, and 0.1~0.5% citric acid. Sugar and pectin caused the increase in sweetness, Hunter's colorimetric characteristics (a, b), and firmness. Citric acid caused decrease in pH, sweetness, firmness. Sensory evaluation results showed that preferences for the melon jam increased as sugar, pectin, and citric acid approached their optimum values and then decreased as they exceeded optimum levels. Consequently, the proposed optimum levels in the ingredient formulation for manufacture of the standard melon jam were 59.0% sugar, 1.4% pectin, and 14.9% citric acid, as based on both numerical and graphic statistical analyses. Ultimately, this study was expected to contribute to the commercialization of melon jams of high quality.