• Corrosion Science and Technology
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• v.20 no.2
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• pp.77-84
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• 2021

This study aims to optimize the DL-EPR test solution for duplex stainless steel S31083 using the Taguchi design. The test solution parameters applied to the Taguchi design are H₂SO₄, NaCl, KSCN concentration, and temperature. In the experimental design, an orthogonal array of 4 levels 4 factor L₁₆(4⁴) was used. Output values for the orthogonal array were used for resolution (degree of sensitization) and selective etch (I_a) values. The optimal test solution conditions were selected by comparing the normalized S/N ratio for the two reaction properties. As a result, the H₂SO₄ and NaCl were identified as the main factors influencing the sensitivity measurement, but the delta statistics showed that the KSCN concentration and temperature had relatively low influence. The optimal condition was identified as 1.5 M H₂SO₄+0.03 M KSCN+1.5M NaCl at 30 ℃. The degree of sensitization presented a tendency to depend on the heat treatment temperature and time in the optimal test solution. This investigation confirmed the possibility of optimizing the experiment solution for the DL-EPR test of stainless steel using the Taguchi technique.

• Journal of the Korean Statistical Society
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• v.31 no.3
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• pp.277-299
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• 2002

Most statistical designs, such as orthogonal designs and optimal designs, are based on a specific statistical model. It is very often that the experimenter does not completely know the underlying model between the response and the factors. In computer experiments, the underlying model is known, but too complicated. In this case we can treat the model as a black box, or model to be unknown. Both cases need a space filling design. The uniform design is one of space filling designs and seeks experimental points to be uniformly scattered on the domain. The uniform design can be used for computer experiments and also for industrial experiments when the underlying model is unknown. In this paper we shall introduce the theory and method of the uniform design and related data analysis and modelling methods. Applications of the uniform design to industry and other areas are discussed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.5
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• pp.328-341
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• 2014

The object of this paper is to develop optimal optical filter, which can be used to identify the financial account and read the information. The five factors which affect the performance of the optical filter are identified as optical glass type, existence of Fe, Photo pic coating type, and coating form. In this study we seek to determine the optimal combination for the best design of the optical filter. For each combination, the performances of optical filter are investigated using the proper experimental equipments and methods. White-state voltage, black-state voltage, and black-state error rate are used for the performance measures. Through the statistical analysis of the performance data collected, we have determined the optimal design of the optical filter.

• Transactions of Materials Processing
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• v.8 no.5
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• pp.471-481
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• 1999

The properties of deformed products are generally dependent upon the distribution of microstureture. It is, therefore, necessary to make the distribution of microstureture uniform in order to achieve the best balance of properties in the final product. This is often a demanding task, even for conventional materials. It is become essential to achieving mechanical integrity and a desired combination of microstructure and properties. The objective mechanical integrity and a desired combination of microsttucture and properties. The objective of this study is to design the optimal die profile which can yield more uniform microstructure in hot extruded product. The microstructure evolution, such as dynamic and static recrystallization as well as grain growth, is investigated using the program com-bined with yada and Senuma's empirical equations and rigid-thermoviscoplastic finite element method. The die profile of hot extrusion is represented by Bezier-curve to define all available profile. In order to obtain the optimal die profile which yields uniform microstructure in the product the FPS(Flexible Polyhedron Search) method is applied to the present study. To validate the result of present study the experimental hot extrusion is performed and the result is compared with that of simulation.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.3
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• pp.218-223
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• 2012

A rigorous electro-optical simulation and ray tracing for an electric field driven liquid crystal Fresnel lens was proposed to obtain design parameters of the electrode pattern of the Fresnel lens. The optimal design was carried out using Taguchi's experimental method for 17.1"($368{\times}229.5$ mm) wide LCD panels with 9 views. For the calculation of the distribution of liquid crystal molecules and the optical transmission of the panel, finite difference method and extended Jones matrix method were used to deal effectively with highly nonlinear and complicated motional equations of the liquid crystal molecules and to obtain the oblique transmission characteristics of the LCD panel. As simulation results, the optimal lengths of the 3 electrodes of the Fresnel lens are 4.0 ${\mu}m$, 30 ${\mu}m$ and 83 ${\mu}m$, respectively, and the locations of the second and third electrodes are 32.9-33.0 ${\mu}m$ and 45.9-46.0 ${\mu}m$, respectively. The optimal applied voltage of the 3 electrodes are found to be 5.75 V, 7.80 V and 11.9 V, respectively.

• Journal of Power Electronics
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• v.15 no.1
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• pp.160-176
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• 2015

This paper presents a method of designing optimal integer- and fractional-order proportional-integral-derivative (FOPID) controllers for a boost converter to gain a set of favorable characteristics at various operating points. A Pareto-based multi-objective optimization approach called strength Pareto evolutionary algorithm (SPEA) is used to obtain fast and low overshoot start-up and dynamic responses and switching stability. The optimization approach generates a set of optimal gains called Pareto set, which corresponds to a Pareto front. The Pareto front is a set of optimal results for objective functions. These results provide designers with a trade-off look-up table, in which they can easily choose any of the optimal gains based on design requirements. The SPEA also overcomes the difficulties of tuning the FOPID controller, which is an extension to the classic integer-order PID controllers and potentially promises better results. The proposed optimized FOPID controller provides an excellent start-up response and the desired dynamic response. This paper presents a detailed comparison of the optimum integer- and the fractional-order PID controllers. Extensive simulation and experimental results prove the superiority of the proposed design methodology to achieve a wide set of desired technical goals.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.1
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• pp.101-105
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• 2011

Determination of ultrasonic frequency and experimental design approach to optimization of ultrasonic soil-washing process for remediation of diesel contaminated soil were investigated. Ultrasonic frequencies of 35, 72, and 100 kHz were used for determination of optimal frequency. $MINITAB^{(R)}$ program was used for experimental design of optimal washing condition. The optimal ultrasonic frequency was 35 kHz. Even though the number of cavitation bubble is little, however cavitation bubbles involving larger energy compared with high frequency was generated. Therefore, the removal efficiency at low frequency was higher than at high frequency. However the input energy has to be considered when the process is applied. The statistical tests from a factorial experiment shows that the application of ultrasound and mechanical mixing are the most important factor for design of an ultrasonic soil washing process. The lab-scale experiments are required to get the optimal condition of ultrasound and mechanical mixing for application of ultrasonic soil washing process.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.226-231
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• 2004

Press fitting method for joining of a hybrid tube and steel ring with small teeth for automotive aluminum/composite hybrid propeller shaft was devised to improve reliability and to reduce manufacturing cost, compared to other joining methods such as an adhesively bonded joint, bolted joint or welded joint. To obtain high strength of the press fit joint, an optimal design method for the teeth was devised with respect to number and shape of the steel teeth. Torsional static, fatigue tests and finite element analysis of the press fit joint were performed with respect to experimental variables. The developed optimal design method predicted well the static torque capability and failure mode of the press fit joint. Also, it provided design guide line of press fit joint for improving torsional static and fatigue characteristics.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.1-8
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• 2004

Various controllable parameters of an experiment have influence on grinding process. In order to get good products with a high quality, these parameters should be considered whether each parameter has relations to the quality. This paper describes the use of the design of experiments to minimize geometric error in surface grinding. Controllable parameters for the design of experiments were selected as spindle speed, table speed, depth of cut and grain size. From the experimental results, a degree of influence between these parameters and the geometric error was evaluated. An optimal set of grinding conditions was obtained by means of analysis of variance(ANOVA).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.106-109
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• 2001

The use of ceramic inserts in hot extrusion dies offers significant technical and economic advantages over other forms of manufacture. These potential benefits can however only be realized by optimal design of the tools so that the ceramic inserts are not subjected to stresses that lead to their premature failure. In this paper, process simulation and stress analysis are thus combined during the design, and a data exchange program has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process. The stress analysis of the dies is used to determine the stress conditions on the ceramic insert by considering contact and interference effects under both mechanical and thermal loads. The results are compared with the experimental ones for verification.