• Journal of the Korean Society for Precision Engineering
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• v.19 no.7
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• pp.97-105
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• 2002

The use of rapid prototyping (RP) has reduced time to market, cut total costs and improved product quality by giving design and manufacturing teams the opportunity to verify and fine tune designs before committing them to expensive tooling and fabrication. In order to improve their unique characteristics according to the working principles, Variable Lamination Manufacturing process (VLM-ST) and corresponding CAD/CAM software (VLM-Slicer) is developed. The objective of this study is to improve the accuracy of VLM-ST process, and it can be done by offset fur cutting error correction, cutting path overrun fur sharp edge and reference shape generation for off-line stacking. It has been shown that, through the verification experiments for given practical shapes, the proposed algorithms are effective for diverse categories of three-dimensional shapes.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.122-129
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• 2005

Shoe with leather upper such as safety and golf shoe requires a roughing process where the upper is roughed fur helping outsole to be cemented well. It is an important and basic process for production of leather shoe but is not automated yet. Thus, there are problems that the defect rate is high and the quality of roughed surface is not uniform. In order to solve such problems, the interest in automation of roughing process is being increased and this paper introduces CAM system for 5-axis automatic roughing machine as one part of automation of roughing process. The CAM system developed interpolates a B-spline curve using points measured from the Roughing Path Measurement System. The B-spline curve is used to generate the tool path and orientation data fer a roughing tool which has not only stiffness but also flexibility to rough the inclined surface efficiently. For productivity, the upper of shoe is machined by side of the roughing tool and tool offset is applied to the roughing tool for machining of inclined surface. The generated NC code was applied to 5-axis polishing machine for the test. The upper of shoe was roughed well along the roughing path data from CAM and the roughed surface was proper fur cementing of the outsole.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.3_4
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• pp.354-363
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• 2003

In this research, an internet-based fabric information system has been developed. Recently, the numbers of textile industries which have their own homepages to advertise their product fabrics fur apparel through the Internet and textile e-Commerce web sites rapidly increase. Unfortunately, traditional fabric information systems based on direct meeting and trust cannot give sufficient information to numerous visitors of the Internet sites including fabric buyers for apparel. They can just view 3-dimensional fabric images and text-based specifications such as fabric density, composition, colors, weight, etc. To solve these problems, the new fabric information system fur apparel has been developed. The web-based fabric information system is composed of the following six modules; $\circled1$ fabric database management system, $\circled2$ a 3-D fabric drape image viewer to illustrate fabric appearances, $\circled3$ a virtual wearing system to apply a fabric to garment designs, $\circled4$ a fabric property viewer to confirm fabric characteristics, $\circled5$ a QC (quality control) document generator to manufacture high qualify garments with a fabric, and$\circled6$actual display mall to view actual fabrics. The fabric information system is simply performed by visitors clicking the buttons hyper-linked with JAVA applets on web browser. The web-based fabric information system enables the web site visitors to understand fabrics shown on the Internet in more details.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1220-1227
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• 2001

The condensation pressure drop fur refrigerant R-22 flowing in the plate and shell heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated trapezoid shape of a chevron angel of $45^{\circ}$. The condensing R-22 flowing down in one channel exchanges heat with the cold water flowing up in the other channel. The effects of the mean vapor quality, mass flux, average imposed heat flux and system pressure of R-22 on the pressure drop were explored in detail. The quality change of R-22 between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.05. The present data showed that pressure drop increases with the vapor quality. At a higher mass flux, pressure drop is higher for the entire range of the vapor quality. Also, a rise in the average imposed heat flux causes an slight increase in the Pressure drop. Finally, at a higher system pressure the pressure drop is found to be slightly lower. Correlation is also provided for the measured pressure drops in terms of the friction factor.

• Journal of the military operations research society of Korea
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• v.33 no.1
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• pp.31-42
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• 2007

While Defense Agency fur Technology and Quality(DTaQ) has been utilized a risk assessment method as a quality assurance activity for defense goods since 1999, a risk assessment method is known to be ineffective to identify defective items. The objective of this study is to propose the new evaluation method, that adjusts a relative priority of evaluation elements using AHP(Analytic Hierarchy Process). Newly evaluated scores have been applied to the risk assessment result of 2005 defective items to test a validity of the new evaluation model. The new model is capable to identify more high and medium risk-level items than the current method. The company risk-level gets more scores than the item risk-level in the new model.

• Journal of Broadcast Engineering
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• v.13 no.3
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• pp.388-400
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• 2008

This paper introduces a cost-effective method fur improving anchor picture quality of a multiview video coding scheme that is mainly based on chroma compensation. Proposed method is applied to both INTER $16{\times}16$ and SKIP modes in only anchor P-pictures. By testing using JVT common test conditions, simulation results show that proposed method can obtain the average BD-PSNR gains fur U and V as 0.136 dB and 0.127 dB, respectively, while maintaining almost same performance for Y (luminance). For the range of low bit-rates, it is observed that average BD-PSNR gains of Y, U, and V are 0.141 dB, 0.494 dB and 0.525 dB, respectively. Necessary computational complexity is very marginal because the number of anchor P-pictures is only 4.18% in comparison with whole coded sequences, however it can be found that the proposed method can significantly improve the coding efficiencies of color components.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.27-29
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• 2004

Orbital TIG welding process being used fur the new construction, the repair of nuclear piping system ana other critical piping. When weld quality is important or there are a large number of similar weld to be made or when access is restricted with manual torch, Orbital TIG welding is most effective process because of practical for out-of-position and high weld quality. Furthermore, typically superior to manual TIG welding process where the pipe remains in place and the tungsten electrode orbits the weld. As smaller and more compact welding head is being developed, could operate in tight spaces and lend itself to this type of application better than any other welding process. Orbital TIG welding has become more and more field practical process.

• 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 Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.59-60
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• 2006

It is bringing out the importance of automated LCD testing equipment that satisfy a definite quality, confidence and testing speed, as LCD enterprises are recently expanding the production and facility investment in proportion to the sudden increase of LCD demand. So far, LCD inspection is however conducted by manual, or the confidence of existing testing equipment falls short of LCD enterprises's standard. It is therefore important to develop the testing equipment that determines the quality of product for production of an excellent LCD.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.477-481
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• 2002

Grinding which is the final finishing step in the machining processes plays an important role fur precision manufacturing because it directly affect the product quality. Since the ground surface is affected by the states of grains and voids on the grinding wheel surface, the wheel should be dressed before the machined surface deteriorates over a quality limit. This paper describes a systematic approach to decide a proper dressing chance. A fabricated eddy current sensor and CCD camera are used to measure the loading on the working wheel surface and to visualize the wheel surface states respectively. The dressing chance can be properly decided through the relation between the variation of the thresholding image of the wheel and the machined surface roughness as the variation of the eddy current sensor output is greater than the detected value previously.