• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.267-272
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• 2007

This paper proposes a new approach fur the detection of facial feature regions using the characteristic of DCT(discrete cosine transformation) thatconcentrates the energy of an image into lower frequency coefficients. Since the facial features are pertained to relatively high frequency in a face image, the inverse DCT after removing the DCT's coefficients corresponding to the lower frequencies generates the image where the facial feature regions are emphasized. Thus the facial regions can be easily segmented from the inversed image using any differential operator. In the segmented region, facial features can be found using face template. The proposed algorithm has been tested with the image MIT's CBCL DB and the Yale facedatabase B. The experimental results have shown superior performance under the variations of image size and lighting condition.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.13-19
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• 2007

This study relates to a new high-speed drive method for the full-HD PDP with 1080 horizontal scanning lines. The characteristics of the new drive method is evaluated considering the characteristics of the display discharge by the high-speed addressing. In this drive method, if the width of the address pulse narrows, the relati0[V]e discharge strength and the discharge time lag of the first display discharge are received the influence of it. Though the change in the applied position of the address pulse is unrelated to the discharge strength, it influences at the discharge time lag. However, the stable display discharges can be induced regardless of the address pulse position and width if the address pulse position is within [$6{\mu}s$] and the width is up to [$0.7{\mu}s$]. From the experiments, it has been understood that the high-speed drive technique with the address pulse of narrow width is sensitively influenced by the space charge because of the insufficiency of wall charge.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.54-60
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• 2007

We constructed a fiber-optic temperature sensor system using a sensor array with 15 fiber Bragg gratings for distributed temperature monitoring in electrical power systems. A polynomial fitting algorithm was used to compensate the nonlinear action of the MEMS tuneable wavelength filter used for Bragg wavelength demodulation Fixed passband wavelengths from a Fabry-Perot ITU filter were used as reference wavelengths for the fitting algorithm which obtained constant accuracy regardless of the wavelength scanning range and frequency. About 0.18[%] of linearity error compared to reference thermocouple thermometer has been obtained in the preliminary experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.2
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• pp.28-33
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• 2003

The piezoelectric transformer converters electrical energy into mechanical energy, It is high efficiency and small size transformer for high output voltage. The piezoelectric transformer operates the resonance frequency and the output voltage waveform is close to sine wave. Therefore, it is suitable for driving the LCD backlight in the notebook computer. In this paper, we discussed about the inverter which os driving piezoelectric transformer by generating sine wave through LC resonance after converting input DC voltage to the gate signal of FET. As the result of experiments, it was showed that the resonance frequency and voltage gain of the piezoelectric transformer was proportional to the load variation, and voltage gain was independent of the input voltage variation.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06b
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• pp.301-303
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• 2006

본 논문은 중립 표정과 같은 표정 측정의 기준이 되는 단서 없이 다양한 내적상태 안에서 얼굴표정을 인식할 수 있는 개선된 시스템을 제안한다. 표정정보를 추출하기 위한 전처리작업으로, 백색화(whitening) 단계가 적용되었다. 백색화 단계는 영상데이터들의 평균값이 0이며, 단위분산값으로 균일한 분포를 갖도록 하여 조명 변화에 대한 민감도를 줄인다. 백색화 단계 수행 후 제 1 주성분이 제외된 나머지 주성분들로 이루어진 PCA표상을 표정정보로 사용함으로써 중립 표정에 대한 단서 없이 얼굴표정의 특징추출을 가능하게 하였다. 본 실험 결과는 83개의 내적상태와 일치되는 다양한 얼굴표정들에서 임의로 선택된 표정영상들의 얼굴표정 인식을 수행함으로써 다양하고 자연스런 얼굴 표정인식을 가능하게 하였다.

• Convergence Security Journal
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• v.2 no.2
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• pp.99-108
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• 2002

In this paper, I propose a reference image updating algorithm for Intruder Detection System using a difference image method that can reliably separate moving objects from noisy background in the image sequence received from a camera at the fixed position. The proposed algorithm consists of four process determines threshold value and quantization, segmentation of a moving object area, generation of adaptive temporary image that removes a moving object area, and updates reference image using median filtering. The test results show that the proposed algorithm can generate reference image very effectively in the noisy environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.1
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• pp.109-117
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• 2000

A full bridge type double resonant high frequency resonant inverter to give VVVF function in the inverter used as power source of induction heating at high frequency is presented in this paper. This proposed inverter can reduce distribution of the switching current because of using the current of serial resonant circuit to the input current of the parallel one and this paper also realize the output control of independence irrespective of the switching frequency using Phase-shift. The analysis of the proposed circuit is generally described by using the normalized parameters. Also, the principle of basic operating and the its characteristics are estimated by the parameters, such as switching frequency, the variation of phase angle ($\phi$) of Phase-shift.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.104-110
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• 2007

Temperature rise characteristics of medium voltage class transformers and dielectric characteristics of its insulation oil according to the loading rate were investigated using the transformer that has thermocouples embedded in the windings. The hottest-spot of the transformer locates at about 2/3 height of the windings where they adjoin each other among the 3 phase windings. The temperature difference between the hottest-spot and top-oil is about $17[^{\circ}C]$ and the value keeps uniformly in short time after changing the loading rate. Capacitance of the oil varies in inverse proportion to temperature and the inclination rate is about -0.0106 that is not dependent on the aging rate. On the other hand the capacitance is increased depending on the aging rate, so the capacitance characteristics of the oil could be applied to the diagnostic technique.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.68-79
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• 2003

In this paper, we propose a system that detects the current speaker in multi-speaker video conference by using lip motion. First, the system detects the face and lip area of each of the speakers using face color and shape information. Then, to detect the current speaker, it calculates the change between the current frame and the previous frame. To accomplish this, we used two CCD cameras. One is a general CCD camera, the other is a PTZ camera controlled by RS-232C serial port. The result is a system capable of detecting the face of current speaker in a video feed with more than three people, regardless of orientation of the faces. With this system, it only takes 4 to 5 seconds to zoom in on the speaker from the initial image. Also, it is amore efficient image transmission system for such things as video conference and internet broadcasting because it offers a face area screen at a resolution of 320X240, while at the same time providing a whole background screen.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.121-128
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• 2009

Iris recognition is a biometric technology which can identify a person using the iris pattern. Recently, iris information is used in many fields such as access control and information security. It is important for the iris recognition system to extract the feature which is invariant to changes in iris patterns. Those changes can be occurred by the influence of lights, changes in the size of the pupil. In this paper, we propose a novel method based on vector summation of gradient orientation vectors. Experimental results show that the proposed method reduces processing time with simple vector calculation, requires small feature space and has comparable performance to the well-known previous methods.