• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.148-151
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• 2009

This paper presents an experimental study of deep-drawing and rubber-pad forming process using titanium alloy sheet. The process and results of the work carried out to investigate the capability of the process and to optimize th process parameters to ensure a sound forming. Room and high temperature tensile tests were carried out at various process conditions and microstructural evaluation was investigated. The experimental investigation was done using 150 ton hydraulic press to produce a deep-drawn part. Both graphite lubricant and polyethylene sheet were essential for defect-free product. Regarding the rubber-pad forming, reasonable formability was obtained only for pure-Ti not for Ti-6Al-4V.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.102-106
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• 2009

Thermal energy control is a important factor in a large size casting and forging. Good control of thermal energy makes characteristics and defect of large cast-forged part, such as large sized forged shell. We have studied about not only large size ring forging process and after heat treatment by FEM simulation. Also, changes of temperature and microstructure for forged shell were predicted. Therefore, we can choose the proper heat treatment condition by FEA. The sectional properties confirmed by practical experiment and evaluation have presented possibilities of process design by computational analysis.

• Proceedings of the Safety Management and Science Conference
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• 2004.05a
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• pp.299-302
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• 2004

Today, several manufacture enterprises are endeavoring constantly to receive order winners of subsidiary company product. There are tendencies to occupy competitive advantage in high position in price competition and in quality etc. But, it is not easy to keep it even if price has been cheap recently. Also, it is hard to be competitive advantage element more, because production smoothing was made much even if there is in quality. To keep or improve present competitive power, the due date rate is becoming importance. Several techniques with MRP, MRP II appeared in the 1970s by method to improve the these due date rate. These techniques have some defects to due date. Therefore, in this paper, MRP wishes to receive the due date rate that is improved more by supplementing having these defect by DBR of TOC.

• IE interfaces
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• v.20 no.1
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• pp.87-93
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• 2007

Burn-in is an engineering method for screening out products containing reliability defects which would cause early failures in field operation. Previously, various burn-in models have been proposed mainly focused on the trade-off of shop repair cost and warranty cost ignoring manufacturing yield. From the view point of a manufacturer, however, burn-in decreases warranty cost at the expense of yield reduction. In this paper, we provide a general model quantifying a trade-off between product yield and reliability, in which any defect distribution from previous yield models can be used. A profit function is expressed in burn-in environments for determining an optimal burn-in time. Finally, the method is illustrated with gate oxide failures which is an important reliability concerns for VLSI CMOS circuits.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.12
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• pp.671-678
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• 2003

This paper proposes an expert system to generate automatically the test table of test system which can highly enhance the quality and productivity of product by inspecting quickly and accurately the defect device on the electronic circuit board tested. The expert system identifies accurately the tested components and the circuit patterns by tracing automatically the connectivity of circuit from electronic circuit database. And it generates automatically the test table to detect accurately the missing components, the misplaced components, and the wrong components for analog components such as resistance, coil, condenser, diode, and transistor, based on the experience knowledge of veteran expert. It is implemented in C computer language for the purpose of the implementation of the inference engine using the dynamic memory allocation technique, the interface with the electronic circuit database and the hardware direct control. And, the validity of the builded expert system is proved by simulating for a typical electronic board model.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.164-169
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• 2002

Recently, LCD(Liquid Crystal Display) is the display product widely used on various fields of industry. This is generally composed of many parts. Among many parts, polarizer film control the intensity of the transmitted light according to the degree of rotation of the polarizer axis. Therefore, this film must be free from defects. But it contains many defects such as the defects caused by dust or different thing, adhesive badness, scratch. Presently, the inspection of these defects is depending on the sight of operator. In this paper, we propose the vision system composed of telecentric lens and optical mirror. This system use the coaxial illumination and the light is specularly reflected on the optical mirror. And we develop the image processing algorithm using the threshold and morphological technique.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.45
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• pp.375-381
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• 1998

For products that are subject to inspections that lead to either acceptance or rejection, the p chart or control chart for proportion defective is applicable. The charting technique approach to quality control aims at alerting its user to any presentations in the properties of a manufactured product. This article presents an important tool available for quality control of a production process at the occurrence of defects in manufactured products at view low levels to improve the efficiency of the manufacturing productivity and to satisfy customer through the reduction of defect rates. To understand the consequences of the level of quality on competitive position, a more technical perspective is needed.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.409-412
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• 2002

The software complexity model makes an estimated of the product software. For a practice of software managed, need to guideline of the static analysis. Especially, Software complexity model introduced for the estimation of software quantity. In case of measurement the software matrices, its need for us to analysis of software qualify and products. In this paper, we represent that the analysis of function point, control structure and interface, volume matrices in various aspect of switching software. Others, their results utilized similar of project and system development.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.131-142
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• 2001

A wrinkling is the instability phenomenon influenced by material properties, shape geometry, forming conditions, stress state, etc. The wrinkling is considered as a critical defect in appearance of product. Many wrinkling prediction methods using thickness strain distribution and farming analysis have been proposed. The wrinkling, however, is not easily predicted precisely by these methods. In this study, the region in the biaxial plane stress state is modeled with a rectangular plate introducing the effective dimension, and critical stress values for the wrinkling are calculated. Prediction index for the wrinkling is then evaluated by normalizing the actual stress with respect to the critical stress. In order to show the validity and efficiency of the method proposed, the wrinkling prediction for a squared sheet in the uniaxial tensile stress and auto-body front finder panel is performed.

• International Journal of Quality Innovation
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• v.7 no.1
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• pp.90-97
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• 2006

The process of producing software differs in many aspects from that of traditional manufacturing. Software is not manufactured in the classical sense. Development of software more closely resembles the development effort that goes into design new product [1-3]. In this article, we first describe the foundations of process improvement, which all processes can share. The process improvement differences between software and manufacturing process are then discussed, and a defect driven process inspection and improvement is introduced. Based on the discussion, two experiments were designed and the results of the results were collected. Through the comparison, we found that some efficient quality improvement approaches can be easily adapted in the software improvement and that the inspection efficiency is also significant.