• 한국전자통신학회논문지
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• 제6권4호
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• pp.517-522
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• 2011

수작업에 의한 기존의 프로젝션(projection) 용접시스템은 작업자의 부주의로 인한 불량이 자주 발생한다. 본 논문에서는 비전카메라를 사용하여 부품과 제품의 인식, 용접 및 수량 관리를 자동으로 수행하는 프로젝션 용접시스템을 제안한다. 제안 시스템은 비전카메라를 사용하여 용접에 사용되는 부품의 유무와 놓인 상태를 검사한다. 그리고 부품의 용접 후에는 제품 수량 카운터와 드레싱 등의 항목을 자동 갱신한다. 기존 시스템과의 비교 실험을 통해 불량률을 감소시키고 생산성을 높일 수 있음을 보인다.

• 한국경영과학회지
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• 제20권1호
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• pp.27-34
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• 1995

In this paper, we have developed a model to determine the input quantity to be processed at each stage of a multi-stage production system in which the yield at each stage may be random and may need reworking at this stage. Yield randomness. especially in a semiconductor industry, is a most challenging problem for production control. The demand for flnal product is uncertain. We have extended the model proposed in Park and Kim[9] to consider a multiple number of reworkings which can be done at any stage prior to or tat the stage whose output in bad, depending on the level of the defect.

• 소성∙가공
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• 제10권6호
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• pp.449-456
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• 2001

The concept of stress wave was introduced through the quantized kinetic energy which is related to the potentional energy change of atom, molecular bond energy. Differentiated molecular bond energy $\varphi$() by the lst order displacement u becomes force F(F = d$\varphi$($u_i$)/du), if resversely stated, causing physically atomic displacement $u_i$. Such physical phenomena lead stress(force/area of applied force) can be expressed by wave equation of linearly quantized physical property. Through the stress wave concept, formation of dislocation, which could not explained easily from a theory of continuum mechanics, can be explained. Moreover, this linearly quantized stress wave equation with a stress concept for grains in a crystalline solid was applied to three typical metallic microstructures and a simple shape. The result appears to be a product from well treated equations of a quantized stress wave. From this result, it can be expected to answer the reason why the defect free and very fine diameters of long crystalline shapes exhibit ideal tensile strength of materials.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.341-344
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• 2006

Finite element analysis and verification experiments were performed in order to find cause of defects such as folding and improper radius around the root area of the thread rolled stud bolts. Thread rolling experiments under several conditions were also carried out to understand the effect of process parameters, such as the rotation speed of the dies and the hardness of the work pieces, on the product quality. Folding defects at the top of thread are attributed to the higher hardness of the work piece and higher rotation speed of the rolling die. It was also found that the radius of screw mainly determined by the radius of the die.

• Journal of Advanced Marine Engineering and Technology
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• 제30권6호
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• pp.731-739
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• 2006

Corrosion and lassitude are very important in the metal construction Currently, the shot peening is used much for removing the defect on the surface, improving the fatigue strength on surface. In this study. the influence of shot peening to the corrosion property were investigated in 3.5% NaCl, 10% HNO3 + 3% HF. 6% FeC13. The immersion test was performed on two kind of specimen(Removed corrosion product. RCP and Continuous immersed specimen: CIS). The immersion periods was 3600hours. Corrosion potential. weight loss, and fatigue crack growth characteristics were investigated. The result, shot peening in corrosion potential showed stable potential. Also, shot peening displayed small Weight loss than un peening. And Fatigue crack resistivity of shot peening in corrosion solution's fatigue crack appeared greatly than un peening.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2005년도 제22차 정기총회 및 학술발표회
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• pp.8-16
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• 2005

비만유전자의 산물인 렙틴은 주로 지방세포에서 생성 분비된다. 렙틴은 뇌 시상하부에 작용하여 식이섭취량을 줄이고 에너지발산을 증가시켜 궁극적으로 체중을 감소시킨다. 따라서 렙틴 또는 렙틴 수용체의 이상은 극도의 대사증후군을 유발한다. 현재까지 렙틴에 관한 연구의 대부분은 사람을 포함한 포유류에서 수행되었다. 렙틴의 생리적 작용은 만복인자뿐만이 아니다. 본고에서는 현재까지 발표된 논문을 중심으로 닭에서 식이섭취, 면역, 지방대사, 번식과 발달, 그리고 스트레스에 관한 렙틴의작용을 검토했다.

• 품질경영학회지
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• 제25권1호
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• pp.56-68
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• 1997

The object of multiresponse optimization is to determine conditions on hte independent variables that lead to optimal or nearly optimal values of the response variables. Derringer and Suich (1980) extended Harrington's (1965) procedure by introducing more general transformations of the response into desirability functions. The core of the desirability a, pp.oach condenses a multivariate optimization into a univariate one. But because of the subjective nature of this a, pp.oach, inexperience on the part of the user in assessing a product's desirability value may lead to inaccurate results. To compensate for this defect, a weighted desirability function is introduced which takes into consideration the vriances of the responses.

• International Journal of Precision Engineering and Manufacturing
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• 제2권4호
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• pp.23-29
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• 2001

The compression behavior of semi-solid materials is studied from a viewpoint of yield criteria and analysis methods. To describe the behavior of materials in semi-solid state, several theories have been proposed by extending the concept of plasticity of porous compressible materials. In the present work, the upper-bound method and the finite element method are used to model the simple compression process using yield criteria of Kuhn and Doraivelu. Segregation between solid and liquid which cause defect of product is analysed for Sn-15%Pb and A356 alloys during deformation in semi-solid state. The comparison of analyses is made according to yield criteria and analysis methods. In addition, the analysis result for semi-solid dendritic Sn-15%Pb alloy is compared with the experimental result of Charreyron et al..

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.444-449
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• 1996

The semiconductor, which is precision product, requires many inspection processes. The surface conditions of the semiconductor chip affect on the functions of the semiconductors. The defects of the chip surface are cracks or voids. As general inspection method requires many inspection procedure, the inspection system which searches immediately and precisely the defects of the semiconductor chip surface is required. We suggest the detection algorithm for inspecting the surface defects of the semiconductor surface. The proposed algorithm first regards the semiconductor surface as random texture and point spread function, and secondly presents the character of texture by linear estimation theorem. This paper assumes that the gray level of each pixel of an image is estimated from a weighted sum of gray levels of its neighbor pixels by linear estimation theorem. The weight coefficients are determined so that the mean square error is minimized. The obtained estimation window(two-dimensional estimation window) characterizes the surface texture of semiconductor and is used to discriminate the defects of semiconductor surface.

• 대한안전경영과학회지
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• 제6권3호
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• pp.197-209
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• 2004

A company wishes to obtain a competitive edge by adopting an efficient logistics information system to control the logistics management process. The elements of the competitive edges a company targets are to maintain good quality, reduce cost and on-time delivery and those competitive edges are closely related to the cycle time of a product. The logistics information system in a company is also closely tied with other business activities than the logistics itself. Therefore it is essential to choose a system that will help rationalize the logistics but also overall business operations along the supply chain from manufacturing to distribution of the products. This paper aims to research and analyze a problem with a logistics information system through case study and to suggest a logistics information system with RFID in place adopted to eliminate problems such as damages, loss and defect rates.