• Journal of the Korea Safety Management & Science
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• v.5 no.4
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• pp.169-185
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• 2003

Recently many researchers contributed to the understanding of Quality Control System, but the use of economics in the design of quality assurance system is limited in treatment of the relationship between the average incoming quality level (or average process quality level) of the incoming lot and the average outgoing quality level of this lot. In this study, a traditional concept of sampling inspection plan for the quality assurance system is extended to a consideration of economic aspects in total production system by representing and analyzing the effects between proceeding and succeeding production process including inspection process. This approach recognizes that the decision at each manufacturing process (or assembly process), is to be determined not only by the cost and the average outgoing quality level of that process, but also by the input parameters of the cost and the incoming quality to the succeeding process. By analyzing the effects of the average incoming and outgoing quality, manufacturing or assembly process quality level and sampling inspection plan on the production system, mathematical models and solution technique to minimize the total production cost for a general product manufacturing system with specified average outgoing quality limit are suggested.

• Journal of Korea Foundry Society
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• v.15 no.4
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• pp.377-387
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• 1995

Partial squeeze die casting is a special die casting process which combines squeeze technique to conventional die casting. The influence of squeeze pressure $(1500-3000kg/cm^2)$ and time-lags(0.5-2.0sec) on defect control, density and microstructure of ADC12 alloy die casts has been studied by appling partial squeeze die casting to air compressure front housing production. Defect free, maximum density of $2.736kg/cm^3$ with sound microstructure of ADC12 alloy die cast has been obtained by partial squeeze die casting technique at the pressure of $2000-2500kg/cm^2$ and time-lags of 1.0-2.0sec.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.361-369
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• 1999

New method of control based upon a physical model of the Stepanov growth technique has been developed. The controller keeps the system stable and completely denies operator's interference into the process. The system demonstrates very reliable results under commercial production of shaped sapphire crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.437-440
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• 1999

New method of control based upon a physical model of the Stepanov growth technique has been developed. The controller keeps the system stable and completely denies operator's interference into the process. The system demonstrates very reliable results under commercial production of shaped sapphire crystals.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.182-188
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• 2000

High-frequency electric resistance welding (HERW) technique is one of the most productive manufacturing method currently available for pipe and tube production because of its high welding speed. In this process, a heat input is controlled by skilled operators observing color and shape of bead but such a manual control can not provide reliability and stability required for manufacturing pipes of high grade quality because of a variety of bead shapes and noisy environment. In this paper, in an effort to provide reliable quality inspection, we propose a neural network-based method for classification of bead shape. The proposed method utilizes the structure of Kohonen network and is designed to learn the skill of the expert operators and to provide a good solution to classify bead shapes according to their welding conditions. This proposed method is implemented on the real pipe manufacturing process, and a series of experiments are performed to show its effectiveness.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.171-171
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• 2000

We have developed m innovative surface inspection system for automated quality control for steel products in POSCO. We had ever installed the various kinds of surface inspection systems, such as a linear CCD and a laser typed surface inspection systems at cold rolled strips production lines. But, these systems cannot fulfill the sufficient detection and classification rate, and real time processing performance. In order to increase detection and classification rate, we have used the Dark, Bright and Transition Field illumination and area type CCD camera, and fur the real time image processing, parallel computing has been used. In this paper, we introduced the automatic surface inspection system and real time image processing technique using the Object Detection, Defect Detection, Classification algorithms and its performance obtained at the production line.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.61-65
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• 2004

As technique that can contribute in quality improvement in design process to overcome shortcoming of traditional quality control, call design or development department quality control activity that is achieved to reduce gun damage shuddering at circle minimizing change or side effect of product performance as off-line quality control. This paper discuss optimal process design of investment projects expansion and replacement investment on each line or individual in the production. Generally optimal plant design has add to a few method by Subsidiary means with use a especial method. And then in this paper, a Robust design is presented, which may be effective to the processes appraisal or improvement. We propose that should make a optimal plant design model for reducing field failure rate to assign by real data on different factors in plant system. Using this model, robust design of taguchi method used in this comprehensive method for reducing field failure rate in plant system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.181-182
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• 2015

The production technologies of free-form concrete panels are emerging to satisfy the need of modern complex shaped in architectural design. This study aims for introducing and improvising the innovative technique called Rod type mold that overcomes the difficulties in some extent by enabling the mold to be used many times, making the shape of the mold adjustable in a flexible way and describing its production process to provide the alternative solution for the construction of free-form mold with considering the features including reusability and optimization cost across its production process. In this study, the freeform concrete panel shape was designed and experiment was done using computerized numeric control machine and rod type mold. The problems appeared on achieving desired shape while operating on rod type mold. The process of identifying all the root causes and contributing causes that may have generated an undesirable condition were done. Consequently, the conical or semicircular shaped was proposed for the end of Numerical control rod and replaced it with the existing flat shaped end to avoid the detachable problem and to improve rod type mold performance.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.704-709
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• 2004

This paper presents the laser processing to adjust the roll and pitch directions of the flex suspension assembly for hard disk drive production. The adjustment is accomplished using a number of laser beam projections that can be approximated using the regression model of the existing measured roll and pitch directions. Information derived from the analysis can be applied to control the quality of flex suspension assembly. The performances of the proposed technique were observed using the flex suspension assembly plant in Thailand as an illustrative case study. The experimental results are given to support the improving manufacturing yields and some economic benefits of the proposed technique.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.1
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• pp.46-52
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• 1998

This paper describes a current-shaping method for the production of constant torque of SRM under the nonlinear magnetic saturation condition. A current detection technique in the inductance increasing region and an approximation technique for modeling of nonlinear inductance profile are adopted. In the proposed system, a single switching angle control and voltage control is used to shape the current waveform for the generation of flat torque at any given load condition. Finally the validity of the proposed method was verified using a constructed 3HP 6/4 SRM.