• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.557-566
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• 2005

In preparation of steamed foam-cakes, effects of whipping time, amount of wheat flour, and amounts of emulsifier on physical properties of the steamed foam cakes were investigated using RSM (response surface methodology). The three independent variables selected for the RSM experiment were whipping time $(X_1)$, amount of wheat flour $(X_2)$, and amounts of wheat flour $(X_2)$, and concentration of emulsifier $(X_3)$ were set for single-stage mixing, respectively. A rotatable central composite design was used for treatment arrangement. The responses from the product for loaf volume, color values and textural properties were analysed. In the analysis of variance for the foam cakes prepared by single-stage method, significant interactions were observed between independent variables (experimental factors) and physical property like loaf volume (p<0.05); textural properties like hardness, gumminess, and chewiness (p<0.05). Among independent variables, concentration of emulsifier had the most effects on physical properties while whipping time. The ordinary points in surface response showed maximal points with physical property like colorimetric b value while other properties revealed saddle points. The 3-dimensional response surface graphs of the predicted regression models displayed decreasing loaf volumes with increasing whipping times and emulsifier concentrations beyond optimum levels. The optimum conditions for best loaf volume and textural property (hardness, gummimess and chewiness) of the products selected by extracting intersectional areas of the contour maps that commonly overlapped all characteristics were; $11\~13$ min whipping time, $470\~486\;g$ amount of wheat flour, and $19\~20\;g$ emulsifier concentration, in case of single-stage method. The median values extracted from the RSM experimental results for optimum manufacturing conditions for single-stage method, i.e., 12 min whipping time, 478 g amount of wheat flour, and 20 g emulsifier concentration were empirically proven to fit the predicted levels of physical properties from the final foam cakes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2401-2409
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• 2013

Reliability analysis with response surface method (RSM) was peformed for a offshore wind turbine (OWT) monopile, which is one of mostly used foundations under 25m seawater depth in the world. The behaviors of a real OWT monopile installed into sandy soils subjected to offshore environmental loads such as wind and wave were analysed using reliability design program (HSRBD) developed in KIOST. Sensitivity analysis of design variables for a OWT monopile with 6m diameter showed that the larger in pile diameter the smaller in probability of failure ($P_f$) of a horizontal deflection and a rotational angle at a pile top, but at a greater than 7m of pile diameter, the reduction rate of $P_f$ was almost constant. It is a necessary that appropriate local design criteria should be designated as soon as possible because there were significant differences on horizontal deflections; $P_f$ was 60% at a minimum criteria 15mm deflection, however, 1.5% $P_f$ when 60mm deflection using 1% of pile diameter from local design criterion standard. Finally, friction angle of sand among many design variables was found most influential design factor in OWT monopile design, and a sensitivity analysis is found an important process to understand which design variables can mostly reduce $P_f$ with a optimum design for maintaining OWT stability.

• Design & Manufacturing
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• v.11 no.2
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• pp.1-8
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• 2017

In this study, we applied microcellular foaming injection molding process to improve the performance of system air-conditioner drain fan which had been produced by injection molding process and studied the optimization of process conditions through 6-sigma process and response surface method (RSM) to reduce weight and deformation of products. Additive type, melt temperature, mold temperature, and injection screw shape were selected as the factor affecting the weight and deformation of the products by carrying out analysis of trivial many through ANOVA and design of experiment (DOE) method. Among the effect factor, we set the addictive type to Long G/F and screw shape to foaming screw which had the highest level of weight reduction and deformation reduction. The amount of foaming agent gas was set at 60 ml, which was the limit beyond which the weight of product did not decrease any more. For melt temperature and mold temperature, we studied the conditions where both weight and deformation were minimized using the RSM. As a result, we set the melt temperature to $250^{\circ}C$, fixed mold temperature to $20^{\circ}C$, and moving mold temperature to $40^{\circ}C$. The improvement effect was analyzed by appling the selected optimal conditions to the production process using the microcellular foaming injection molding. The results showed that the mean weight of product was measured to be 1,420g which was 19% lower than that measured in the current process. The standard deviations of the weights were found to be similar to those in the current process and it showed a low dispersion. The mean deformation was measured to be 0.9237mm, which represented a 57% reduction compared to the mean deformation in the current process, and the standard deviation decreased from 0.3298mm to 0.1398mm. Moreover, we analyzed the process capability for deformation, and the results showed that the short-term process capability increased from 2.73 to 6.60 which was even higher than targeted level of 6.0.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.2
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• pp.29-43
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• 2019

The calibration of microscopic traffic simulation models has received much attention in the simulation field. Although no standard has been established for it, a genetic algorithm (GA) has been widely employed in recent literature because of its high efficiency to find solutions in such optimization problems. However, the performance still falls short in simulation analyses to support fast decision making. This paper proposes a new calibration procedure using a dual GA and central composite design (CCD) in order to improve the efficiency. The calibration exercise goes through three major sequential steps: (1) experimental design using CCD for a quadratic response surface model (RSM) estimation, (2) 1st GA procedure using the RSM with CCD to find a near-optimal initial population for a next step, and (3) 2nd GA procedure to find a final solution. The proposed method was applied in calibrating the Gipps car-following model with respect to maximizing the likelihood of a spacing distribution between a lead and following vehicle. In order to evaluate the performance of the proposed method, a conventional calibration approach using a single GA was compared under both simulated and real vehicle trajectory data. It was found that the proposed approach enhances the optimization speed by starting to search from an initial population that is closer to the optimum than that of the other approach. This result implies the proposed approach has benefits for a large-scale traffic network simulation analysis. This method can be extended to other optimization tasks using GA in transportation studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.8
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• pp.654-659
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• 2008

This paper is to suggest a concept design of the permanent magnet type magnetic resonance imaging (MRI) device based on the parameter optimization method. Pulse currents in the gradient coils will introduce the effect of eddy currents in the ferromagnetic material, which will worsen the quality of imaging. In order to equalize the magnetic flux in the MRI device for good imaging, the eddy current effect in the ferromagnetic material must be taken into account. This study attempts to use the design of experiment (DOE) and the response surface method (RSM) for equalizing the magnetic flux of the permanent magnet type MRI device using that the magnetic flux can be calculated directly using a commercial finite element analysis package. As a result, optimal shapes of the pole and the yoke of the PM type MRI device can be obtained. The commercial package, ANSYS, is used for analyzing the magnetic field problem and obtaining the resultant magnetic flux.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.745-752
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• 2012

Transverse flux machine (TFM) has been proved to be very suitable for high-torque, low-speed, and direct-drive situation in industry. But the complex structures and costly permanent magnets (PMs) are two key limitations of its wide range of applications. This paper proposes a new claw pole TFM (ACPTFM) which features an assembled claw pole stator and using the lamination steels material to overcome the complex structures. By combining response surface methodology (RSM) with design of experiment, an optimum design method is put forward to improve the PM's contribution to the torque in order to save the PM's amount. The optimum design results demonstrate the validity of the proposed optimum design method and the optimized model. Eventually, the finite-element analysis (FEA) calculation method, which is used in the optimization process, is verified by the experiments in a prototype.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.1
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• pp.167-174
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• 2005

The design for cold extrusion dies is very important, because the die insert is subjected to very high radial and hoop stresses. The design of cold extrusion dies has many constrained conditions. In this paper, the used assumptions are such that the yield strength of each ring is selected according to the allowable tensile or compressive hoop stress in each ring and the maximum allowable inner pressure, when yielding occurs in one ring of the dies, is obtained by the proposed equation. In order to obtain design variables, such as diameter ratios and interferences, using the maximum inner pressure, the flexible tolerance method was used for shrink-fitted thick-walled cylinders. ANSYS APDL was used to perform the repeated analysis of deformation of the dies due to the variation of the design variables. The response surface methodology is utilized to analyze the relationship between the design variables and the maximum radial displacement of the die insert during extrusion. From the results, it is found that outer diameter of the die insert has the largest effect on the minimization of maximum radial displacement at the inner surface of the dies.

• Journal of Electrical Engineering and Technology
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• v.12 no.5
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• pp.1842-1850
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• 2017

Reducing the noise and vibration of the BLDC motors is very essential for some special applications. In this paper, a new structural design is introduced to increase the natural frequencies of the stator in BLDC motors as increasing the natural frequencies can reduce the severe effects of the structural resonances, including high levels of noise and vibration. The design is based on placing a single hole on definite regions at the stator cross sectional area (each region contains one tooth and its upper parts in the stator yoke) in an optimum way by which the natural frequencies at different modes are shifted to the higher values. The optimum diameter and locations for the holes are extracted by the Response Surface Methodology (RSM) and the modal analyses in the iterative process are done by Finite Element Method (FEM). Moreover, the motor performance by the optimum stator structure is analyzed by FEM and compared with the prototype motor. Preventing the stator magnetic saturation and the motor cogging torque enhancement are the two constraints of the optimization problem. The optimal structural design method is applied experimentally and the validity of the design method is confirmed by the simulated and experimental results.

• Journal of the Korea Institute of Building Construction
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• v.13 no.6
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• pp.565-578
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• 2013

Batch production is common in repetitive construction projects, and it is not unusual for different batch sizes to be used by contractors in one project. While several scheduling methods, such as the Linear Scheduling Method (LSM) and the Repetitive Scheduling Method (RSM) have been proposed and used, no mathematical method for repetitive construction projects has been developed, and it is difficult to consider different batch sizes with the existing methods. An original mathematical algorithm for scheduling repetitive projects with different batch sizes is proposed in this study. This algorithm is illustrated with assumptions of resource continuity and single path in a project and introduces new terms, control batch and critical batch. The algorithm logics and mathematical equations are validated by comparison with the outcomes from a graphical scheduling approach through a simple and practical hypothetic project. As a result, it is expected that the proposed algorithm can be easily adapted and extended to computer software for scheduling, and can be a starting point for research on batch size management in repetitive construction projects.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.797-804
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• 2012

Magnesium has a long tradition of use as a lightweight material in the field of automotive industry. This paper presents the design optimization process of Mg armrest frame to minimize its weight by replacing the steel frame. formerly, the analysis of steel armrest frame was peformed to determine the design specifications for Mg armrest frame. The initial design of Mg armrest frame was carried out by topological optimization technique. After six types of design variables and four types of response variables were defined, DOE(Design of Experiment) and RSM (Response Surface Method) were applied in order to measure sensitivity of design variables and realize optimization through regression model. After design optimization, the weight of the optimized Mg armrest frame was reduced by about 3% compared to the initial design of the Mg frame and was decreased by 41.7% in comparison with that of the steel frame. Some prototypical armrest frames were also made by die casting process and tested. The results were satisfying for its design specifications.