• Proceedings of the KWS Conference
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• 2002.10a
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• pp.366-371
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• 2002

Because of the environmental problems, automotive companies are trying to reduce the weight of car body. Therefore, TRIP(TRansformation Induced Plasticity) steels, which have high strength and ductility have been developed. Welding process is a complex process; therefore deciding the optimal welding conditions on the basis of experimental data is an effective method. However, trial-and-error method to decide the optimal conditions requires too many experiments. To overcome these problems, response surface methodology was used. Response surface methodology is a collection of mathematical and statistical techniques that are used in the modeling and analysis of problems in which a response of interest is influenced by several variables and the objective is to optimize this response. This method was applied to the resistance spot welding process of the TRIP steel to optimize the welding parameters.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2786-2795
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• 2000

Recently, the technology for internal polishing is needed for ultra-clean machining for the prevention of corrosion and pollution of parts is the area of high technology industries such as semiconductor, electronics, telecommunication optics, aerospace, and motors. In this study, an internal polishing system using the magnetic force was developed for the production of ultra-clean tubes with averaged surface roughness ranging from 0.2㎛ to 0.05㎛ or less, and magnetic abrasives composed of WC/Co powder were developed, After finding the optimal condition on each, machining characteristics using newly developed abrasive were analyzed. Form the results obtained by experimental design method, the optimal polishing condition was analyzed and, thhereafter internal polishing was done.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.43-50
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• 2009

Semi dry cutting known as MQL (Minimum Quantity Lubrication) machining is widely spreaded into the machining shops nowadays. The objective of this research is to suggest how to derive optimum cutting conditions for the milling process in MQL machining. To reach these goals, a bunch of finish milling experiments was carried out while varying cutting speed, feed rate, oil quantity, depth of cut and so on with MQL. Then, response surface analysis was introduced for the variance analysis and the regression model with the experimental data. Finally, desirability function based on regression model was used to obtain optimal cutting parameters and verification experiment was done.

• Transactions of the Korean Society of Automotive Engineers
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• v.1 no.3
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• pp.63-73
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• 1993

In this paper, fuzzy control algorithm for the speed ratio control of the electro-hydraulic rig type continuously variable transmission(CVT) was proposed and the CVT performance tests were carried out for the optimal operation of the engine simulator. The experimental results for the constant throttle and the acceleration modes showed that the engine can be run on the optimum operating line, representing the power and economy mode, by the fuzzy control of the CVT speed ratio. Comparing the PID control with the fuzzy control, it was found that the fuzzy control showed better performance with the faster rising time and smaller steady state error. The result of this study can be used as basic design materials for developing the transmission control unit of the CVT.

• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.1-6
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• 2004

In this paper, the performance of a wave absorbing system using an inclined punching plate, was investigated. Using the multi-domain boundary element method (BEM), the reflection coefficients of an inclined punching plate were tested with various design parameters, such as inclined angle, porosity, and wave frequencies. To confirm the numerical solutions, the systematic model test was conducted at 2-D tank and square tank. The numerical results were in good agreement with the experimental results within the entire frequency range. It was found that an inclined punching plate had an excellent wave absorbing efficiency, compared to a horizontal one. Also, the optimal range of an inclined angle had an excellent wave absorbing efficiency, compared to a horizontal one the optimal range of the inclined angle is 10°<β<20°. The developed wave absorber was installed at KRISO's square basin, and is working effectively for various model tests.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.720-722
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• 2000

Single phase series commutator motors is widely used in various home appliances, such as vacuum cleaner, electric mixers, electrical tools, etc. This paper deals with the characteristics of single phase series commutator motors of which parameters varied with stator turns and stack length to find optimal electric and magnetic loading. We try to measure these data through the experiments with several prototype motors. The experimental results show some specific stator turns and stack length with which this motor has the highest efficiency.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.182-183
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• 2019

In this study, the optimization of mixing proportion of press-forming board with blast furnace slag, pearlite and bottom ash was investigated using the response surface methodology. Ten Mixing proportions of specimens were designed by the response surface design, and then flexural failure load, moisture content and water absorption of specimens were measured. As a result of the reaction surface analysis based on the experimental results, it was possible to derive the optimal mixing proportion with the satisfaction of 93%.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.694-697
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• 2001

A optimal soft switching technique for A/DC full bridge converter is proposed. variable soft switching single stage AC/DC full bridge converter with unit power factor are presented in this paper. Using soft switching, we can reduce a switching losses. As a result, achieving good power factor and achieving a good efficiency. We search a optimal soft switching technique in this paper and to verify the theoretical analysis of the presented AC/DC full bridge converter, a design example is given with its Pspice and Psim simulation and experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.623-628
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• 2000

This paper deals with an analysis and reduction of escalator vibration by using the response surface model. Optimization of the escalator vibration is performed by minimization of the vibration responses which are measured at steps. The response surface models of the factors are constructed by using the experimental data based on the D optimal design method. The multi-objective optimization is also performed by applying desirability function and overlaid contour plot techniques. The optimal solution, which is obtained for a typical escalator system, is applied to reduce the escalator vibration.

• International Journal of Korean Welding Society
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• v.2 no.2
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• pp.47-50
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• 2002

Because of the environmental problems, automotive companies are trying to reduce the weight of car body. Therefore, TRIP(TRansformation Induced Plasticity) steels, which have high strength and ductility have been developed. Welding process is a complex process; therefore deciding the optimal welding conditions on the basis of experimental data is an effective method. However, trial-and-error method to decide the optimal conditions requires too many experiments. To overcome these problems, response surface methodology was used. Response surface methodology is a collection of mathematical and statistical techniques that are used in the modeling and analysis of problems in which a response of interest is influenced by several variables and the objective is to optimize this response. This method was applied to the resistance spot welding process of the TRIP steel to optimize the welding parameters.