• Journal of Korean Electronics
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• v.25 no.7
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• pp.35-35
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• 2005

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1997.04a
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• pp.93-95
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• 1997

• Environmental Engineering Research
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• v.7 no.4
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• pp.239-245
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• 2002

• Proceedings of the PSK Conference
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• 2000.10a
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• pp.199.1-199.1
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• 2000

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.3
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• pp.241-247
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• 2006

We propose a character recognition system to extract the component reference names from printed circuit boards (PCBs) automatically. The names are written in horizontal, vertical, reverse-horizontal and reverse-vertical directions. Also various symbols and figures are included in PCBs. To recognize the character and orientation effectively, we divide the recognizer into two stages: character classification stage and orientation classification stage. The character classification stage consists of two sub-recognizers and a verifier. The rotaion-invarint features of input pattern are then used to identify the character independent of orientation. Each recognizer is implemented as a neural network, and the weight values of verifier are obtained by genetic algorithm. In the orientation classification stage, the input pattern is compared with reference patterns to identify the orientation. Experimental results are presented to verify the usefulness of the proposed system.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.195-200
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• 2008

Hydroxylated polychlorinated biphenyl (OH-PCBs)는 PCB의 CYP-dependent oxidation의 대사물로서 잠재적 독성이 강하고 지질친화성을 가지며 생물군에 지속적인 축적성을 나타낸다. OH-PCBs의 해독화 효능을 조사하기 위하여 channel catfish 간에서 glucuronidation을 통한 해독작용 가능성을 평가하고 biphenyl 구조에 다양한 염소치환의 구조적 차이점에 따른 영향을 비교 분석하여 보았다. Kinetic parameters에서 $K_m$과 $V_{max}$는 $192{\sim}871{\mu}M$, $869{\sim}1774$ pmo1/min/mg으로써 4'-OH-PCB35와 4'-OH-PCB69이 가장 높은 속도의 glucuronidation을 나타냈으며, 구조적 차이점에서 phenolic group에 한 개의 염소치환이 존재할 경우보다 두 개의 염소치환이 존재할 경우에 OH-PCBs(p<0.001)의 glucuronidation에 대한 $V_{max}$를 현저하게 낮추는 결과를 보였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.394-401
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• 2003

We consider a PCB grouping problem arising from the electronic industry. Given a surface mounting device, several types of PCBs and a number of component feeders used to assemble the PCBs. the optimization problem is the PCB grouping problem while minimizing setup time of component feeders. We formulate the problem as an Integer programming model and propose a column generation approach to solve the Integer programming formulation. In this approach we decompose the original problem Into master problem and column generation subproblem Starting with a few columns in the master problem. we generate new columns successively by solving subproblem optimally. To solve the subproblem. we use a branrh-and-rut approach. Computational experiments show that our solution approach gives high quality solutions in a reasonable computing time.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.11a
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• pp.23-27
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• 2000

Simultaneous Switching Noise (SSN) propagated through parallel power and ground planes in high-speed multilayer printed circuit boards (PCBs) causes malfunction of both digital and analog circuits. To reduce SSN, decoupling capacitors are generally used in the PCBs. In this paper, we improve the equivalent circuit model of decoupling capacitor in high-frequency range to analyze the effect of SSN reduction accurately. The analysis is performed by the microwave and RF design system (MDS) method and the finite difference time domain (FDTD) method. We compared the results by the ideal capacitor model with those by the proposed model.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.406-414
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• 1997

A real-time inspection system is developed using line scan cameras. Several improved algorithms are proposed for real-time detection of defects in this automated inspection system. The major improved algorithms include the preprocessing, the threshold decision, and the clustering algorithms. The preprocessing algorithms are for exact binarization and the threshold decision algorithm is for fast detection of defects in 1-D binary images. The clustering algorithm is also developed for fast classifying of the defects. The system is applied to PCBs(Printed Circuit Boards) inspection. The typical defects in PCBs are pits, dent, wrinkle, scratch, and black spots. The results show that most defects are detected and classified successfully.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.35-42
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• 2003

Differential signaling has become a popular choice for high-speed interconnection schemes on Printed Circuit Boards (PCBs), offering superior immunity to external noise. However, conventional differential transmission lines on PCBs have problems, such as crosstalk and radiated emission. To overcome these, we propose a Twisted Differential Line (TDL) structure on a multi-layer PCB. Its improved immunity to crosstalk noise and the reduced radiated emission has been successfully demonstrated by measurement. The proposed structure is proven to transmit 3 Gbps digital signals with a clear eye-pattern. Furthermore, it is subject to much less crosstalk noise and achieves a 13 dB suppression of radiated emission. Index Terms - Twisted Differential Line, Differential Signaling, Crosstalk, Radiated Emission, Transmission Line, Twisted Pair