• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.6
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• pp.30-38
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• 1998

In this paper, a new CMOS current-mode integrator is proposed that can apply the basic building block of the low-voltage high frequency current-mode active filter. And tuning circuits that control the gain and unity gain frequency of them is designed. The proposed integrator is composed of the CMOS complementary circuit which can extend transconductance of an integrator. Therefore, the unity gain frequency which is determined transconductance and MOSFET gate capacitance can be expanded by the proposed integrator. The unity gain frequency of the proposed integrator is increased about two times larger than that of the conventional continuous-time integrator with NMOS-gm. And also, cut-off frequency and gain of the active filter can be controlled with the designed tuning circuit. From the result, we can reduce errors on fabrication. And then, 3rd-order low-pass active filter is designed as an application circuits. These results are verified by the small signal analysis and the 0.8$\mu\textrm{m}$ parameter HSPICE simulation.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1069-1079
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• 2005

Though there have been many methods to detect features in spatial domain, in the case of a compressed image it has to be decoded, processed and encoded again. Alternatively, we can manipulate a compressed image directly in the Discrete Cosine Transform (DCT) domain that has been used for compressing videos or images in the standards like MPEG and JPEG. In our previous work we proposed a model-based discontinuity evaluation technique in the DCT domain that had problems in the rotated or non-ideal discontinuities. In this paper, we propose a fuzzy filtering technique that consists of height fuzzification, direction fuzzification, and forty filtering of discontinuities. The enhancement achieved by the fuzzy tittering includes the linking, thinning, and smoothing of discontinuities in the DCT domain. Although the detected discontinuities are rough in a low-resolution image for the size (8${\times}$8 pixels) of the DCT block, experimental results show that this technique is fast and stable to enhance the qualify of discontinuities.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2662-2670
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• 2009

The effect of the reflector type for the SAW filter on the characteristics of the slanted finger IDT filter have been studied by computer simulation. The IDT was evaporated by Aluminum-Copper alloy. The design condition was optimized by the phase shift of the SAWfilter for WCDMA. We have employed that the number of pairs of the input and output IDT are 50 pairs and the thickness are $5,000{\AA}$, and the width and the space of reflector are $3.6{\mu}m$ and $2.0{\mu}m$, respectively. Frequency response of the fabricated SFIT filter has the property that the center frequency is about 190MHz and bandwidth at the 3dB is probably 8.2MHz. And we could obtain that the return loss is less then 16dB, the ripple characteristics is probably 4dB and the triple transit echo is less then 18dB after when we have matched impedance.

• Journal of Satellite, Information and Communications
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• v.5 no.1
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• pp.32-37
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• 2010

The algorithm of multiple channel signal processing requires the flexibility of variable frequency band, efficient allocation of transmission power, and flexible frequency band reallocation to satisfy various service types which requires different transmission rates and frequency band. There are three methods including per-channel approach, multiple tree approach, and block approach performing frequency band reallocation method by channelization and dechannelization in the multiple-channel signal. This paper proposes an improved per-channel approach for converting the frequency band of multiple carrier signals efficiently. The proposed algorithm performs decimation and interpolation using CIC(cascaded integrator comb filter), half-band filter, and FIR filter. In addition, it performs filtering of each sub-channel, and reallocates channel band through FIR low-pass filter in the multiple-channel signal. The computer simulation result shows that the perfect reconstruction of output signal and the flexible frequency band reallocation is performed efficiently by the proposed algorithm.

• Journal of KIISE:Software and Applications
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• v.34 no.6
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• pp.539-548
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• 2007

Mobile content adaptation is a technology of effectively representing the contents originally built for the desktop PC on wireless mobile devices. Previous approaches for Web content adaptation are mostly device-dependent. Also, the content transformation to suit to a smaller device is done manually. Furthermore, the same contents are provided to different users regardless of their individual preferences. As a result, the user has difficulty in selecting relevant information from a heavy volume of contents since the context information related to the content is not provided. To resolve these problems, this paper proposes an enhanced method of Web content adaptation for mobile devices. In our system, the process of Web content adaptation consists of 4 stages including block filtering, block title extraction, block content summarization, and personalization through learning. Learning is initiated when the user selects the full content menu from the content summary page. As a result of learning, personalization is realized by showing the information for the relevant block at the top of the content list. A series of experiments are performed to evaluate the content adaptation for a number of Web sites including online newspapers. The results of evaluation are satisfactory, both in block filtering accuracy and in user satisfaction by personalization.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2005.11a
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• pp.201-204
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• 2005

동영상에서 얼굴을 인식하는 기술은 Eigen-Face를 이용하는 방법, 템플릿을 이용하는 방법 등과 같이 다양한 방법이 연구되어지고 있다. 하지만 이들 기법들이 모두 동영상에서 얼굴영역을 검출했을지는 모르지만 얼굴영역이 영상에서 차지하는 위치와 크기를 일정하게 제한하고 있다. 그 중에서 입력되는 영상이 촬영 도구로부터 제한된 거리에서 촬영되어 얻어 지거나 실험을 통해 얻어진 영상을 이용하여 얼굴영역을 검출한다. 하지만 실제 다양한 응용분야에서 얼굴영역 검출 기술을 이용하기 위해서는 이러한 제한된 입력 영상뿐만이 아니라 어떠한 환경에서의 입력 영상에서도 얼굴영역을 검출할 수 있어야 한다. 본 논문은 근거리뿐만이 아니라 원거리에서 획득한 영상에서도 얼굴영역을 검출할 수 있으며, 얼굴의 특징 추출과 예측기법을 통하여 보다 향상된 얼굴영역 검출을 할 수 있다. 움직임 정보와 얼굴색상정보를 이용하여 8x8블록을 만들고 이런 블록 정보들을 특정한 규칙에 적용함으로써 얼굴영역을 후보를 검출하게 된다. 그리고 후보 얼굴영역의 고유한 특징들을 추출하고 칼만 필터를 적용한 예측기법을 통하여 얼굴영역 판단하게 된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1387-1394
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• 2011

In this paper, a low-area symbol timing offset synchronization structure for WLAN Modem is proposed. Using CSD(Canonic Signed Digit) coefficients and CSS(Common Sub-expression Sharing) technique for the filter implementation, efficient structure for multiplication block can be obtained. Function simulation for proposed structure is done by using the preamble with timing offset. Through Verilog-HDL coding and synthesis, it is shown that the proposed symbol timing offset synchronization structure can be implemented with low-area semiconductor.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.6
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• pp.81-88
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• 2004

In this paper, we propose a new objective quality assessment method considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.113-122
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• 2006

In this paper, we propose a fuzzy method to control bit-rate in the DCT Domain. The method consists of a bit-rate allocation with fuzzy measures and a least-distortion bit-rate reduction. Fuzzy measures are calculated by the code length, the discontinuity ambiguity, and the neighborhood momentum in each DCT block. These measures are summed with weights and form a reduction fuzziness to indicate the degree of preferable reduction. Using the reduction fuzziness. each DCT block is filtered by the least-distortion reduction method to adjust the bit-rate for the target bandwidth. In the experiment, we show the results that the transcoded video quality by the method is better and the bandwidth is more regular than those of existing methods in both visually and quantitatively.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.102-107
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• 2000

In general text compression techniques cannot be used directly in image compression because the model of text and image are different Recently, a new class of text compression, namely, block-sorting algorithm which involves Burrows and Wheeler transformation(BWT) gives excellent results in text compression. However, if we apply it directly into image compression, the result is poor. So, we propose simple method in order to improve the lossless compression performance of image. The proposed method can be divided into three steps. It is decomposed into ten subbands with the help of symmetric short kernel filter. The resulting subbands are block-sorted according to the method by BWT, and the redundancy is removed with the help of an adaptive arithmetic coder. Experimental results show that the proposed method is better than lossless JPEG and LZ-based compression method(PKZIP).