• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.351-354
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• 2003

Titanium alloys are a vital element for developing advanced structural components, especially in aerospace applications. However, process design for successful forming of titanium alloy is a difficult task, which is to be achieved within a very narrow range of process parameters. Presented in this paper is a finite element - based optimal design technique as applied to ductile fracture minimization process design in backward extrusion of titanium alloys.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.359-364
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• 1993

As advanced method for the automatic generation of parametric models in computer-aided design systems is required for most of two-dimensional model which is represented as a set of geometric elements, and constr- aining scheme formulas. The development system uses geometirc constrainis and topology parameters which are derived from feature recognition and grouping the design entities into optimal ones from pre-designed drawings. The aim of this paper is to present guidelines for the application and development of parametric design modules for the standard parts in mechaniscal system, the basic constitutional part of mold base, and other 2D features.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.467-468
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.372-378
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• 2005

Finite element analysis of concrete slab system in apartment building was executed using the tables of orthogonal arrays, and optimal design process was proposed. At first, experimental results show that sound peak components to influence the overall level and the rating of floor impact sound insulation were coincident with natural frequencies of the reinforced concrete slab. Finite element model of concrete slab was compared with experimental results, and well corresponded with an error of less than 10%. The tables of orthogonal arrays were used for finite element analysis with 8 factors. 3 related to material properties and 5 related to slab shape parameters and its results were analyzed by statistical method, ANOVA. The most effective factor among them was slab thickness, and main effect factor from slab shape parameters was different from each natural frequency. The interaction was found in the higher mode over $3^{rd}$ natural frequency. From main effect plot and interaction plot, the optimal design factor to increase the natural frequency was determined.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.44-51
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• 2006

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product for the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.18-21
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• 2008

Acoustic design parameters of a half-wave resonator are studied experimentally for acoustic stability in a model combustor. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of damping factor and sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. The diameter and the number of a half-wave resonator, its distribution are selected as design parameters for optimal tuning of the resonator. Acoustic damping capacity increases as the resonators with diameter increases. The optimum number of resonators or the optimum open-area ratio decreases as boundary absorption decreases.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.2
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• pp.145-152
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• 1999

This paper presents an optimal design method for fuzzy logic controllers using genetic algorithms. In general, the design of fuzzy logic controllers has difficulties in the acquisition of exper's knowledge and relies to a great extent on empirical and heuristic knowledge which, in many cases, cannot be objectively justified. So, the performance of the controller can be degraded in the case of plant parameter variations or unpredictable incident which the designer may have ignored, and parameters of the fuzzy logic controller obtained by expert's control action may not be global. To solve these problems, the proposed method using genetic algorithms in this paper, can tune the parameters of fuzzy logic controller including scaling factors and determine the appropriate number of fuzzy reles systematically and automatically. We provide the second drder dead time plant and inverted pendulum system to evaluate the feasibility and generality of our proposed method. Comparison shows that the proposed controller can producd higher accuracy and a smaller number of fuzzy rules than manually tuned fuzzy logic controller.

• Journal of the Semiconductor & Display Technology
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• v.11 no.1
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• pp.73-78
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• 2012

In this study, the optimal process condition was induced about the pillar arrangement process of applying the screen printing method in the manufacture process of vacuum glazing panel. The high precision screen printing is technology which pushes out the paste and spreads it by using the squeegee on the stainless steel plate in which the pattern is formed. The screen printing method is much used in the flat panel display field including the LCD, PDP, FED, organic EL, and etc for forming the high precision micro-pattern. Also a number of studies of screen printing method have been conducted as the method for the cost down through the improvement of productivity. The screen printing method has many parameters. So we used Taguchi method in order to decrease test frequencies and optimize this parameters efficiently. In this study, experiments of pillar arrangement were performed by using Taguchi experimental design. We analyzed experimental results and obtained optimal conditions which are 4 m/s of squeegee speed, $40^{\circ}$ of squeegee angle and distance between metal mask and glass.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.769-772
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• 2005

This paper deals with the aspects of die design for the multistage fine tooth hub gear in the cold forging process. In order to manufacture the cold forged product fur the precision hub gear used as the ARD 370 system of bicycle, it examines the influences of different designs on the metal flow through experiments and FE-simulation. To find the combination of design parameters which minimize the damage value, the low gear length, upper gear length and inner diameter as design parameters are considered. An orthogonal fraction factorial experiment is employed to study the influence of each parameter on the objective function or characteristics. The optimal punch shape of fine tooth hub gear is designed using the results of FE-simulation and the artificial neural network. To verify the optimal punch shape, the experiments of the cold forging of the hub gear are executed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.11-14
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• 2008

Acoustic design parameters of a half-wave resonator are studied experimentally for acoustic stability in a model acoustic tube. According to standard acoustic-test procedures, acoustic-pressure signals are measured. Quantitative acoustic properties of sound absorption coefficient are evaluated and thereby, the acoustic damping capacity of the resonator is characterized. The diameter and the number of a half-wave resonator and the diameter of the tube are selected as design parameters for optimal tuning of the resonator. Optimum acoustic damping capacity is observed at smaller open area ratio as the resonator diameter increases.