• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.2335-2338
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• 2003

This paper presents a real-time PCB (Printed Circuit Board) vision inspection system. This system can detect the OPEN and SHORT of the PCB which of the line width is 150$\mu\textrm{m}$. Our PCB inspection system is based on the referential method. Since the size of the captured PCB image is very large, the image is divided into 512${\times}$512 images to apply the accurate alignment efficiently. To correct the misalignment between the reference image and the inspection image, pattern matching is performed. In order to implement the proposed algorithm in real-time, we use the SIMD instruction and the double buffering structures. Our experiential results show the effectiveness of the developed inspection algorithm.

• Proceedings of the Korean Institute of Interior Design Conference
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• 1999.04a
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• pp.3-6
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• 1999

The purpose of this study is to analyze the characteristics of exhibition circulation through the movement pattern. It looks into the factoers under the influence with the visitor's movement. The method of analysis of investigation by following after visitors. The viewing behavioral of exhibition based on the time, speed, proportion of appreciation is classfied into three types of the profound, the general, the passing viewers. The characteristics of the viewing form of these patterns largely depend on the space elements which are the structure form. And particularly the position of exit, the width of exhibition space and the connection of exhibition space stand out the disparity of the factor of the spatial structure These three patterns bring about a lot of encounter in the exhibition space according to the difference of these routes consequently. So appropriate to the each pattern can offer visitors to more effective environment of exhibition.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.4
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• pp.551-561
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• 1997

Mixed convection of air in a horizontal concentric cylindrical annulus is investigated numerically. Isothermal boundary conditions are prescribed at the inner and outer cylinders, with the inner cylinder being warmer. The forced flow is induced by the outer cylinder which is rotating slowly with constant angular velocity with its axis at the center of the annulus. The effect of the forced flow on the flow pattern and heat transfer of natural convection is investigated for the annulus of (inner-cylinder radius/gap width) = 1. There appear two eddies, one eddy or no eddy according to the Rayleigh and Reynolds numbers. Map of the three flow regimes is constructed on the Ra-Re plane. (author). 28 refs., 9 figs., 2 tabs.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.213-219
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• 2004

This paper proposes speaker recognition algorithm which includes the pitch parameter for the peak and valley. The time-frequency hybrid method for pitch extraction is valuable in that it can improve resolution in the time domain and accuracy in the frequency domain at the same time. It makes reference pattern using membership function and performs vocal track recognition of common character using fuzzy pattern matching in order to include time variation width for non-linear utterance for proposed method, speaker recognition experiments are carried out using vowels and number sounds.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.63-69
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• 1998

A new current controlled PWM technique with NPC structure is proposed in this paper. A current controlled PWM technique with neutral-point-clamped pulse-width modulation inverter composed of main switching devices which operates as switch for PWM and auxiliary switching devices to clamp the output terminal potential to the neutral point potential is described. The proposed current controller has a first and second current band. The switching pattern will be made by the first current band. According to the second current band, the output state of the switching pattern is changed into positive and negative state. This inverter output contains less harmonic content and lower switching frequency than that of conventional current controlled PWM technique at the same current limit. Two inverters are compared analytically and the performance is investigated by the computer simulation.

• Journal of the Optical Society of Korea
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• v.3 no.1
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• pp.15-19
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• 1999

The formation of spontaneous transverse optical patterns was investigated in a single feedback mirror system using nematic liquid crystals as nonlinear optical media. By varying the size of an input beam and the feedback distance, we obtained various interesting transverse optical patterns as well as the hexagonal pattern which are predicted theoretically assuming plane wave input. We can explain theoretically these characteristics of various pattern by introducing a ratio of the beam half width and spatial wavelength of the patterns. We have observed that as this ratio increased, the number of spot constituting the patterns also increased. Finally the patte군 evolved into the sucessive hexagon in the transverse plane.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.229-234
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• 2005

The dynamic crack growth in ductile steel is investigated by means of the impact loaded 3 point bending (3PB) specimens. Results from experiments and numerical simulations are compared to each other. A modified 3PB specimen designed with the reduced width at its ends has been developed in order to avoid the initial compressive loading of the crack tip and also to avoid the uncertain boundary conditions at the impact heads. Numerical simulations of the experiments are made by using a finite element method (FEM) code, ABAQUS. The high speed photography is used to obtain the crack growth and the data of the crack tip opening displacement (CTOD). The direct measurements of the relative rotations of two specimen halves are made by using the Moire interference pattern.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.5
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• pp.199-204
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• 2002

In order to recognize the deterioration of insulation system by partial discharge (PD), the characteristics of PD patterns which are occurring at the interface between epoxy and rubber materials in extra high voltage cable joints, have been investigated. The artificial defects such as voids, metal particles, insulation fiber and water impregnated insulation fiber are planted between the interfaces. A high frequency partial discharge detection system was used for measuring PD signals. An analysis of the PD patterns is focused on the shape of PD pattern, phase, width and time-dependence for each artificial defect. The PD Patterns in each defect show the different behaviors and it is suggested that the precise discrimination of PD patterns could be used for the diagnosis of deterioration in the insulation systems.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1055-1059
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• 1998

The correlation between the propagation of electrical tree and distributions of partial discharge(PD) pulses accompanying with electrical tree of bush type in low density polyethylene were discussed. We measured the growth of electrical tree by using optical microscope and PD data simultaneously. The PD data detected and analyzed were PD magnitude, repetition rate, average discharge power, average phase angle, and $\psi$-q-n distribution pattern. The average discharge power and repetition rate of PD had good linear relation with area of tree. Repetition rate and peak discharge magnitude and width of discharge phase angle increased with the tree.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.522-533
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• 1999

This paper proposes speaker recognition algorithm which includes both the pitch parameter and the fuzzy inference. This study proposes a pitch detection method PVPF(peak and valley pitch detection fuction) by means of comparing spectra which utilizes the transform characteristics between time and frequency. In this paper, makes reference pattern using membership function and performs vocal tract recognition of common character using fuzzy pattern matching in order to include time variation width for non-linear utterance time.