• 설비공학논문집
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• 제25권12호
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• pp.654-659
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• 2013

This paper presents a numerical optimization of louvered fins to enhance the JF factor in terms of the design parameters, including the fin pitch, the number of louvers, the louver angle, the fin thickness, and the re-direction louver length. We carried out a parametric study to select the three most important parameters affecting the JF factor, which were the fin pitch, number of louvers, and the louver angle. We optimally designed the louvered fin by using 3rd-order full factorial design, the kriging method, and a micro genetic algorithm. Consequently, the JF factor of the optimum model increased by 16% compared to that of the base model. Moreover, the optimum model reduced the pressure drop by 17% with a comparable heat transfer rate.

• 대한기계학회논문집B
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• 제28권7호
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• pp.879-886
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• 2004

A numerical optimization has been carried out to determine the shape of the three-dimensional channel with oblique ribs attached on both walls to enhance turbulent heat transfer. The response surface based optimization is used as an optimization technique with Reynolds-averaged Navier-Stokes analysis of fluid flow and heat transfer. Shear stress transport (SST) turbulence model is used as a turbulence closure. Numerical results fur heat transfer rate show good agreements with experimental data. four dimensionless variables such as, rib pitch-to-rib height ratio, rib height-to-channel height ratio, streamwise rib distance on opposite wall to rib pitch ratio, and the attack angle of the rib are chosen as design variables. The objective function is defined as a linear combination of heat-transfer and friction-loss related coefficients with a weighting factor. D-optimal method is used to determine the training points as a means of design of experiment. Sensitivity of the objective parameters to each design variable has been analyzed. And, optimal values of the design variables have been obtained in a range of the weighting factor.

• 소성∙가공
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• 제31권5호
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• pp.302-308
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• 2022

In this study, the weight of the platen was reduced using the structural strength analysis and topology optimization design of the extruder by finite element analysis. The main components of the extruder such as the stem and billet, were modeled, and the maximum stress and safety factor were verified through structural strength analysis. Based on the results of the structural strength analysis, the optimal phase that satisfies the limitation given to the design area of the structure and maximizes or minimizes the objective function was obtained through a numerical method. The platen was redesigned with a phase-optimal shape, the weight was reduced by 40% (from the initial weight of 11.1 tons to 6.6 tons), and the maximum stress was 147.49 MPa safety factor of 1.86.

• 한국소음진동공학회논문집
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• 제14권1호
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• pp.3-9
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• 2004

This paper introduces the experimental analysis of the resonator in the rolling piston type compressor for air conditioner. The resonator located between cylinder and hearing is a major factor in the noise reduction of the rotary compressor. Several shapes for the resonator which can be built in the space limitations are derived. Then optimal resonator type for the noise reduction is determined by noise tests. 6 design parameters of the type are found and optimal level for each design factor is deduced from Taguchi method.

• 대한산업공학회지
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• 제39권5호
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• pp.367-373
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• 2013

In this article, we deal with a design problem for determining the levels of noise factors in the Taguchi method. First, the proposed levels by Taguchi method is reviewed in case of smaller-the-better performance characteristics. We obtain the optimal levels of noise factors minimizing the mean square error of SN(signal to Noise) ratio and compare the optimal levels with the levels proposed by Taguchi method under the first and second order models. Secondly, the concept of V-optimality is applied to determining the levels of noise factors.

• 품질경영학회지
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• 제45권4호
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• pp.889-902
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• 2017

Purpose: The orthogonality and trace optimal properties are desirable for constructing designs of experiments. This article focuses on the determination of the sizes of experiments for the balanced trace optimal resolution-V fractional factorial designs for 2-level factorial designs, which have near-orthogonal properties. Methods: In this paper, first we introduce the trace optimal $2^t$ fractional factorial designs for $4{\leq}t{\leq}7$, by exploiting the partially balanced array for various cases of experimental sizes. Moreover some orthogonality criteria are also suggested with which the degree of the orthogonality of the designs can be evaluated. And we appraise the orthogonal properties of the introduced designs from various aspects. Results: We evaluate the orthogonal properties for the various experimental sizes of the balanced trace optimal resolution-V fractional factorial designs of the 2-level factorials in which each factor has two levels. And the near-orthogonal 2-level balanced trace optimal resolution-V fractional factorial designs are suggested, which have adequate sizes of experiments. Conclusion: We can construct the trace optimal $2^t$ fractional factorial designs for $4{\leq}t{\leq}7$ by exploiting the results suggested in this paper, which have near-orthogonal property and appropriate experimental sizes. The suggested designs can be employed usefully especially when we intend to analyze both the main effects and two factor interactions of the 2-level factorial experiments.

• 한국전기전자재료학회논문지
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• 제33권4호
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• pp.297-302
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• 2020

A coverglass pattern was designed to improve the annual electrical energy production of a building-integrated photovoltaic (BIPV) module installed in the exterior walls of buildings. The transmittance pattern was calculated using ray tracing, and the results were derived by optimizing the simulation using Taguchi's method. We obtained the optimal pattern by analyzing the conventional patterns for improving the transmittance and derived design factors by quantifying the pattern. By calculating the influence of electrical energy on each design factor, we obtained the optimal coverglass pattern that produced the maximum annual electrical energy. The annual electrical energy production improved by approximately 11.79% compared to the non-patterned coverglass.

• Journal of Electrical Engineering and Technology
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• 제8권3호
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• pp.581-587
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• 2013

Among different linear motors, single-sided linear induction motors have been widely used in industry due to their simplicity and low construction cost. However, these types of motors suffer from low efficiency and power factor. In this paper, an effective procedure is proposed to design single-sided linear induction motors. The designed motor is simulated in MATLAB software in order to investigate the effect of design parameters on the performance of the machine. Regarding the obtained results, the Genetic Algorithm is employed to optimize the design considering product of efficiency and power factor as objective function. The results show significant improvement of the performance. Finally, experimental results and 2D finite element method is used to validate the model parameters and the optimization results.

• 한국구조물진단유지관리공학회 논문집
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• 제2권4호
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• pp.194-200
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• 1998

Risk, probability of failure, which includes various uncertainties and influential factors of performance should be accounted for in engineering system. Recently, several different methods to analysis risk evaluation evolved and one of the practical method is FOSM (First Order Second Moment Method ). FOSM method is derived in terms of terms coefficient of variance to uncertainties which influence various factor. For risk evaluation and uncertainty analysis in hydraulic design system, load-capacity relationship is adopted in this paper. Sample catchment with design of sewer system is applied, which plots safety factor vs. risk. Risk evaluation and uncertainty analysis are very to important develop optimal design model in hydraulic system

• 품질경영학회지
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• 제45권2호
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• pp.293-306
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• 2017

Purpose: In this study, an optimal design level of influencing factors on semiconductor polishing process was determined to minimize flexion of both sides on wafers. Methods: First, significant interactions are determined by the stepwise regression method. ANOVA analysis on SN ratio and mean of dependent variable are performed to draw mean adjustment factors. In addition, the optimal levels of mean adjustment factors are decided by comparing means of each level of mean adjustment factors. Results: As a result of ANOVA, a mean adjustment factor was determined as a width of formed flexion on the plate. The mean of the difference has the nearest to 0 in the case when the width of formed flexion has level 2 (4mm). Conclusion: Optimal design levels of semiconductor polishing process are determined as follows; (i) load applied to the wafer carrier has a level 1 (3psi), (ii) load applied to the wafer has a level 1(3psi), (iii) the amount of slurry supplied during polishing has a level 3 (300 co/min), (iv) the width of formed flexion on the plate has level 2 (4mm).