• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• 제22권1호
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• pp.10-15
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• 2011

In this review, we have provided an overview of the environmental risk factors for attention deficit hyperactivity disorder (ADHD), focusing on the major environmental toxicants related to the disorder. Researchers have indicated that since the characteristics of ADHD are complex, the disorder’s etiology involves multiple genes of moderate effect interacting with environmental factors. The possible roles of prenatal and perinatal exposure have been the main focus of research on environmental risk factors for ADHD. Among environmental toxicants, we reviewed the potential effects on the development of ADHD of exposure to lead, nicotine, alcohol, polychlorinated biphenyls (PCBs), and dioxin. Further, for the each neurotoxicant, clinical prevention or intervention strategies aimed at reducing a child’s risk from environmental toxic insults have been presented.

• 경영과정보연구
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• 제34권2호
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• pp.67-78
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• 2015

본 연구는 작업 순서에 따라 달라지는 준비비용을 갖는 인쇄회로기판의 생산 일정계획 문제를 다룬다. 본 연구에서 다루는 문제는 생산할 인쇄회로기판의 유형들이 주어져있으며, 이는 한 대의 부품장착 설비를 통해 생산되는 환경에서, 작업 투입 순서에 따라 달라지는 준비 비용의 총합을 최소화는 작업 투입순서를 결정하는 것이다. 이 문제는 NP-hard로 알려져 있으며, 이에 해를 도출하기 위한 메타 휴리스틱 기법을 제시한다.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.1-4
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• 2006

Recently, Ball Grid Arrays(BGAs) are getting used more frequently for a package type. The connectors on a BGA consist of a large number of small solder balls in a grid shape on its bottom side. However, since balls of BGAs mounted on PCBs are not visible, inspection before mounting them is indispensable. High speed non-contact 3D measurement technologies are necessary far real-time measurement of ball height, the most important inspection item. In this paper, an accurate 3D data acquisition system for BGAs is proposed that can acquire 3D profile at high speed using a 3D smart camera and laser slit ray projection. Some clipping and morphological filtering operations are employed to remove spiky error data, which occur due to reflections from some ball area to camera direction.

• 품질경영학회지
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• 제25권1호
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• pp.135-141
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• 1997

The Copper-Clad Laminate (CCL) is a main electronic component of specialtype printed circuit boards (PCBs) such as Silver Through Hole PCB. This CCL should have high reliability under the aging test, and usually the test is done at a higher temperature (110-$150^{\circ}C$) than the normal. Then, this test condition of high temperature may cause such quality problems as hole eccentricity and reduction of distance between part holes. After measuring the CCL shrinkage affected by temperature, the correction factor of a press mold was a, pp.ied to solve these problems. The results showed that the tolerance of hole pitch(${\pm}$$100{\mu}m$) was satisfactory and the internal and external failure costs were reduced by 55%.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 추계수산관련학회 공동학술대회발표요지집
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• pp.237-238
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• 2000

최근 산업사회의 발전에 따라 수계 오염문제가 심각하게 대두되고 있다. 따라서 이들 오염물질에 대한 모니터링을 위한 방법들이 강구되고 있으며, 이 중에서 어류 간의 cytochrome P450 호소계는 지방친화성 물질의 오염상태를 평가할 수 있는 물질로 알려지고 있다(Payne et al., 1987). PCBs(Polychlorinated biphenyls)와 HCB(Hexachlorobenzene)는 유기염소계 화합물로서 환경중에 널리 분포하고 있으며, 이중 PCBs는 신경계, 면역계 및 내분비계 등 생체내에 미치는 영향이 크므로 내분비장애물질(endocrine disruptor)로 분류되고 있고, HCB는 독성이 강한 화합물로서 주로 농업에서 fungicide로서 사용되어 왔으며. 다양한 산업 연소과정의 부산물로 발생되고 있다. (중략)

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.51-54
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• 2002

As digital systems continue to use components with faster edge rate and clock speeds, transmission of the digital information can take place many troubles. The increasing requirement for controlled impedance PCBs becomes both a critical success factor and a design challenge. Especially, the noise sources in digital system include the noise in power supply, ground and packaging due to simultaneous switching of signal, signal reflections and distortions on single and multiple transmission lines. This paper simulates the tracks controlled impedance with the test coupon. So, it can saves the design time and supports the economical PCB design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.308-310
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• 1997

In this paper, to anlayze electromagnetic distribution, measure the variation of relative permittivity of Glass-epoxy substrate for Computer-main-board and Tenon substrate for handphone or PCS in the frequency range $100[MHz]{\sim}1[GHz]$, in room temperature. To measure relative permittivity, suggested the Microstripline method. As the frequency increase, the variation of relative permittivity of Glass-epoxy is bigger than Tefoln's. And simulate the electromagnetic distribution on the PCBs in the infinite region applying the open boundary condition with these results by Finite Element Method.

• 산업공학
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• 제18권3호
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• pp.297-307
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• 2005

PCB assembly is a complicated and difficult process to optimize due to the necessity of simultaneous consideration of component’s rack assignment and board mounting sequencing. An efficient PCB assembly method is developed by using neighboring positioned identical components information as well as quantity and size of the components. It is found that same type of components are located closely each other by checking real PCBs and interviewing with PCB designers in practice. Better performance of the developed procedure is obtained along with more number of total components and more number of neighboring positioned identical components cases. Simulation models are developed using Visual C++ for performance evaluation purposes of the suggested heuristic.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제6권3호
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• pp.135-140
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• 2017

SMT장비는 전자 부품을 흡착하여 PCB상에 정확히 실장 하는 장비이다. 이를 위해서는 중간 위치에 설치된 카메라 앞에서 정지하여 비전검사를 한 후 실장 위치로 이동한다. 본 논문에서는 카메라 앞에서 멈추어 비전 검사를 한 후 실장하는 방법(stop-motion)과 카메라 앞에서 움직이면서 비전 검사를 한 후 실장하는 방법(fly-motion)을 비교하였다. 그 결과 fly-motion의 시간 효율이 stop-motion보다 9% 증가한 것을 보여주었다.

• 한국표면공학회지
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• 제46권4호
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• pp.158-161
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• 2013

Recently, the weight reduction and miniaturization of the electronics have placed great emphasis. The miniaturization of PCB (Printed Circuit Board) as main component among the electronic components has also become progressed. The use of acid copper plating process for Via-Filling effectively forms interlayer connection in build-up PCBs with high-density interconnections. However, in the case of copper-via filled in a bath, which is greatly dependent on the effects of additives. This paper discusses effects of Cl ion on the filling of PCB vias with electrodeposited copper based on both electrochemical experiment and practical observation of cross sections of vias.