• Sim-seong Yeon-gu
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• v.31 no.2
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• pp.215-220
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• 2016

• 월간 기계설비
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• s.293
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• pp.72-82
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• 2014

대구는 60~70년대 골목마다 '드르륵 드르륵' 재봉틀 소리가 들릴 정도로 섬유산업의 메카로서 우리나라 경제발전을 견인했다. 그러나 섬유산업이 쇠퇴하면서 대구는 20여년 째 장기적인 침체를 겪고 있다. 이에 따라 대구광역시는 섬유산업을 비롯 마케팅, 문화, 비즈니스를 집적화 한 융합 공간을 통해 섬유도시 대구의 정통성과 한국섬유의 고급 브랜드 이미지 창출, 글로벌 마케팅 기지 역할을 할 대구 텍스타일 콤플렉스(DTC, Daegu Textile Complex) 건립사업을 지난 2010년부터 추진하여 내년 4월 개관을 앞두고 있다. DTC는 대구시 동구 봉무동 이시아폴리스 부지 1만3천$730m^2$에 지하 2층 지상 9층 규모(연면적 $49,667.96m^2$)로 1,200억원(국비 720억원, 시비 427억원, 민자 53억원)이 투입됐다. 본지는 지난 11월 10일 준공검사를 끝내고 마무리 작업에 한창인 DTC의 현장에서 기계설비 및 소방공사를 담당한 (주)백산이엔씨(대표 김주환) 서광주 현장소장과 시공사인 화성산업(주)(대표 이홍중) 김경표 현장소장을 만났다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.117-125
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• 2013

Variations of springback in stamped parts are induced by the uncontrollable noises including the variation of incoming material properties, lubrication and other forming process parameters. Reduction of springback variation is very important during springback compensation processes on stamping dies and assembly processes. To reduce the variation of springback, a robust optimization methodology which uses complex method combined with orthogonal array is proposed. The proposed method is applied to the robust design of U-channel die for the reduction of side wall curl. It is shown that the drawbead and die radius of U-channel draw die can be effectively optimized by the proposed method.

• Journal of Drive and Control
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• v.11 no.4
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• pp.32-38
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• 2014

The hydraulic fuse, which responds to the suddenly increased flow on rupture of a line and shuts off the fluid flow, would prevent large spillage of liquid. The quick-acting hydraulic fuse, which is mainly composed of a poppet, a seat, and a spring, must be designed to minimize the leaked flow and to prevent high collision speed between the poppet and seat during fuse operation on a line rupture. The optimal design parameters of a quick-acting hydraulic fuse were searched using the genetic algorithm and the complex method that are kinds of constrained direct search methods. The dynamic behavior of a quick-acting hydraulic fuse was researched using computer simulations that applied the obtained optimal design parameters.

• Journal of Drive and Control
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• v.9 no.3
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• pp.29-36
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• 2012

The hydraulic cylinder is used for actuating the roller-link type rotating floodgate which controls the volume of water in the reservoir. The locating points of hydraulic cylinder are restricted to the limited space and determined to minimize the cylinder force necessary for actuating the floodgate. Generally, the head end point of cylinder is fixed at underground and the rod end point of cylinder is connected to the support link. Therefore there exist three design variables to be determined to minimize the cylinder force within the rotating range of floodgate. First, the mathematical model of the roller-link type rotating floodgate is derived to find the cylinder force corresponding to the floodgate angle. Then, the optimal locating point of hydraulic cylinder is searched using the complex method that is one kind of constrained direct search method.

• Journal of the Korea Institute of Building Construction
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• v.7 no.3
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• pp.16-22
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• 2007

• 시스템엔지니어링워크숍
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• s.6
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• pp.147-149
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• 2005

• Korean Architects
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• s.514
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• pp.28-33
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• 2012

• Journal of Internet Computing and Services
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• v.4 no.3
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• pp.39-46
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• 2003

Generally, the existing watermarking techniques for copyright protection of a digital image are fragile in geometric distortion and all watermark extractions need the same time regardless of degree of distortion. In this paper, we propose the incremental watermarking technique that used a Complex Wavelet Transform(CWT) in order to solve these problems. The proposed incremental watermarking technique embeds a watermark in a phase component after a CWT with an original image, and a watermark is extracted from an watermarked image by stages. A watermark owner can insist on copyright of an image after comparing a correlation between the extracted watermark and the original watermark if it is larger than the threshold. Also, the incremental watermark extraction determines the extraction time of a watermark by the level of distortion. The proposed technique through performance evaluation displayed that it was robust in geometric distortion than the existing watermarking technique.

• Polymer(Korea)
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• v.36 no.3
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• pp.309-314
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• 2012

To control degradation rate of biodegradable poly(lactide)s (PLA), the stereochemical PLAs with different ratios of $d$-lactide and $l$-lactide units were synthesized by the ring open polymerization and a degradation behavior was measured by a Langmuir film balance. Degradation rates of mixture monolayers on alkaline subphase were investigated as a function of optical purity of mixture component, 100, 99, 97 and 95%. As increasing their optical purity, melting temperatures of mixtures from stereocomplexation increased. The degradation rate of mixture monolayer with 100% optical purity was much slower than that of each homopolymer one and the others showed 2 step degradation behaviors. In the first step, the degradation which is faster than that of each homopolymer occurs in the uncomplexed region, and secondly, the degradation occurred in the complexed region which showed similar degradation rate to that of 100% optical purity. These results indicate that the alkaline degradation of stereochemical PLAs could be controlled by stereochemistry and stereocomplexation between enantiomer PLAs.